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Sample records for rostral intralaminar thalamic

  1. High field fMRI reveals thalamocortical integration of segregated cognitive and emotional processing in mediodorsal and intralaminar thalamic nuclei

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    Coraline Danielle Metzger

    2010-11-01

    Full Text Available Thalamocortical loops, connecting functionally segregated, higher order cortical regions and basal ganglia, have been proposed not only for well described motor and sensory regions, but also for limbic and prefrontal areas relevant for affective and cognitive processes. These functions are, however, more specific to humans, rendering most invasive neuroanatomical approaches impossible and interspecies translations difficult. In contrast, non invasive imaging of functional neuroanatomy using fMRI allows for the development of elaborate task paradigms capable of testing the specific functionalities proposed for these circuits. Until recently, spatial resolution largely limited the anatomical definition of functional clusters at the level of distinct thalamic nuclei. Since their anatomical distinction seems crucial not only for the segregation of cognitive and limbic loops but also for the detection of their functional interaction during cognitive-emotional integration, we applied high resolution fMRI on 7 Tesla.Using an event related design, we could isolate thalamic effects for preceding attention as well as experience of erotic stimuli. We could demonstrate specific thalamic effects of general emotional arousal in mediodorsal nucleus and effects specific to preceding attention and expectancy in intralaminar centromedian/parafascicular complex (CM/PF. These thalamic effects were paralleled by specific coactivations in the head of caudate nucleus as well as segregated portions of rostral or caudal cingulate cortex and anterior insula supporting distinct thalamo-striato-cortical loops. In addition to predescribed effects of sexual arousal in hypothalamus and ventral striatum, high resolution fMRI could extent this network to paraventricular thalamus encompassing laterodorsal and parataenial nuclei. We could lend evidence to segregated subcortical loops which integrate cognitive and emotional aspects of basic human behaviour such as sexual

  2. High Field fMRI Reveals Thalamocortical Integration of Segregated Cognitive and Emotional Processing in Mediodorsal and Intralaminar Thalamic Nuclei

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    Metzger, C. D.; Eckert, U.; Steiner, J.; Sartorius, A.; Buchmann, J. E.; Stadler, J.; Tempelmann, C.; Speck, O.; Bogerts, B.; Abler, B.; Walter, M.

    2010-01-01

    Thalamocortical loops, connecting functionally segregated, higher order cortical regions, and basal ganglia, have been proposed not only for well described motor and sensory regions, but also for limbic and prefrontal areas relevant for affective and cognitive processes. These functions are, however, more specific to humans, rendering most invasive neuroanatomical approaches impossible and interspecies translations difficult. In contrast, non-invasive imaging of functional neuroanatomy using fMRI allows for the development of elaborate task paradigms capable of testing the specific functionalities proposed for these circuits. Until recently, spatial resolution largely limited the anatomical definition of functional clusters at the level of distinct thalamic nuclei. Since their anatomical distinction seems crucial not only for the segregation of cognitive and limbic loops but also for the detection of their functional interaction during cognitive–emotional integration, we applied high resolution fMRI on 7 Tesla. Using an event-related design, we could isolate thalamic effects for preceding attention as well as experience of erotic stimuli. We could demonstrate specific thalamic effects of general emotional arousal in mediodorsal nucleus and effects specific to preceding attention and expectancy in intralaminar centromedian/parafascicular complex. These thalamic effects were paralleled by specific coactivations in the head of caudate nucleus as well as segregated portions of rostral or caudal cingulate cortex and anterior insula supporting distinct thalamo–striato–cortical loops. In addition to predescribed effects of sexual arousal in hypothalamus and ventral striatum, high resolution fMRI could extent this network to paraventricular thalamus encompassing laterodorsal and parataenial nuclei. We could lend evidence to segregated subcortical loops which integrate cognitive and emotional aspects of basic human behavior such as sexual processing. PMID:21088699

  3. Phase-dependent activity of neurons in the rostral part of the thalamic reticular nucleus with saccharin intake in a cue-guided lever-manipulation task.

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    Aoki, Ryuhei; Kato, Risako; Fujita, Satoshi; Shimada, Jun; Koshikawa, Noriaki; Kobayashi, Masayuki

    2017-03-01

    Neurons in the rostral part of the thalamic reticular nucleus (rTRN) receive somatosensory and motor information and regulate neural activities of the thalamic nuclei. Previous studies showed that when activity in visual TRN neurons is suppressed prior to the visual stimuli in a visual detection task, the performance of the task improves. However, little is known about such changes in the rTRN preceding certain events. In the present study, we performed unit recordings in the rTRN in alert rats during a cue-guided lever-manipulation task in which saccharin was provided as a reward. Changes in neural activity during saccharin intake were observed in 56% (51 of 91) of the recorded neurons; the firing rates increased in 21 neurons and decreased in 23 neurons. Seven neurons both increased and decreased their firing rates during saccharin intake. Changes in firing rates during the reward-waiting stage between task termination and saccharin intake were also observed in 73% (37 of 51) of the neurons that responded to saccharin intake. Increased activity during saccharin intake did not correlate with increased activity during lever-manipulation or activity during the reward-waiting stage. However, decreased activity during saccharin intake was correlated with activity during the reward-waiting stage. These results suggest that rTRN neurons have phase-dependent changes in their activity and regulate the thalamic activities. Furthermore, the decreased activity of rTRN neurons before reward may contribute to refine somatosensory and motor information processing in the thalamic nuclei depending on the status of mind such as expectation and attention. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The intralaminar thalamus – an expressway linking visual stimuli to circuits determining agency and action selection

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    Simon eFisher

    2014-04-01

    Full Text Available Anatomical investigations have revealed connections between the intralaminar thalamic nuclei and areas such as the superior colliculus that receive short latency input from visual and auditory primary sensory areas. The intralaminar nuclei in turn project to the major input nucleus of the basal ganglia, the striatum, providing this nucleus with a source of subcortical excitatory input. Together with a converging input from the cerebral cortex, and a neuromodulatory dopaminergic input from the midbrain, the components previously found necessary for reinforcement learning in the basal ganglia are present. With this intralaminar sensory input, the basal ganglia are thought to play a primary role in determining what aspect of an organism’s own behavior has caused salient environmental changes. Additionally, subcortical loops through thalamic and basal ganglia nuclei are proposed to play a critical role in action selection. In this mini review we will consider the anatomical and physiological evidence underlying the existence of these circuits. We will propose how the circuits interact to modulate basal ganglia output and solve common behavioral learning problems of agency determination and action selection.

  5. A role for midline and intralaminar thalamus in the associative blocking of Pavlovian fear conditioning.

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    Sengupta, Auntora; McNally, Gavan P

    2014-01-01

    Fear learning occurs in response to positive prediction error, when the expected outcome of a conditioning trial exceeds that predicted by the conditioned stimuli present. This role for error in Pavlovian association formation is best exemplified by the phenomenon of associative blocking, whereby prior fear conditioning of conditioned stimulus (CS) A is able to prevent learning to CSB when they are conditioned in compound. The midline and intralaminar thalamic nuclei (MIT) are well-placed to contribute to fear prediction error because they receive extensive projections from the midbrain periaqueductal gray-which has a key role in fear prediction error-and project extensively to prefrontal cortex and amygdala. Here we used an associative blocking design to study the role of MIT in fear learning. In Stage I rats were trained to fear CSA via pairings with shock. In Stage II rats received compound fear conditioning of CSAB paired with shock. On test, rats that received Stage I training expressed less fear to CSB relative to control rats that did not receive this training. Microinjection of bupivacaine into MIT prior to Stage II training had no effect on the expression of fear during Stage II and had no effect on fear learning in controls, but prevented associative blocking and so enabled fear learning to CSB. These results show an important role for MIT in predictive fear learning and are discussed with reference to previous findings implicating the midline and posterior intralaminar thalamus in fear learning and fear responding.

  6. A role for midline and intralaminar thalamus in the associative blocking of Pavlovian fear conditioning

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    Auntora eSengupta

    2014-05-01

    Full Text Available Fear learning occurs in response to positive prediction error, when the expected outcome of a conditioning trial exceeds that predicted by the conditioned stimuli present. This role for error in Pavlovian association formation is best exemplified by the phenomenon of associative blocking, whereby prior fear conditioning of conditioned stimulus (CS A is able to prevent learning to CSB when they are conditioned in compound. The midline and intralaminar thalamic nuclei (MIT are well placed to contribute to fear prediction error because they receive extensive projections from the midbrain periaqueductal gray – which has a key role in fear prediction error – and project extensively to prefrontal cortex and amygdala. Here we used an associative blocking design to study the role of MIT in fear learning. In Stage I rats were trained to fear CSA via pairings with shock. In Stage II rats received compound fear conditioning of CSAB paired with shock. On test, rats that received Stage I training expressed less fear to CSB relative to control rats that did not receive this training. Microinjection of bupivacaine into MIT prior to Stage II training had no effect on the expression of fear during Stage II and had no effect on fear learning in controls, but prevented associative blocking and so enabled fear learning to CSB. These results show an important role for MIT in predictive fear learning and are discussed with reference to previous findings implicating the midline and posterior intralaminar thalamus in fear learning and fear responding.

  7. Neuropsychological correlates of a right unilateral lacunar thalamic infarction

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    Werf, Y; Weerts, J; Jolles, J; Witter, M; Lindeboom, J; Scheltens, P.

    1999-01-01

    OBJECTIVES—To report on a patient with a lacunar infarction in the right intralaminar nuclei of the thalamus. The role of the thalamic intralaminar nuclei in cognitive function is as yet insufficiently known. The patient described has shown signs of apathy and loss of initiative, in combination with cognitive deficits, which have persisted essentially unaltered up to the present day since an abrupt onset 17 years ago.
METHODS—High resolution MRI was performed to show the extent of the lesion; a combination of published and experimental neuropsychological techniques was administered to show the nature of the cognitive defects; Single photon emission computed tomography (SPECT) was employed to obtain a measure of cortical perfusion.
RESULTS—Brain MRI disclosed an isolated lacunar infarction in the dorsal caudal intralaminar nuclei of the thalamus. Neuropsychological evaluation indicated problems with attention and concentration, executive disturbances, and memory deficits both in the visual and verbal domains. The memory deficits could not be attributed to problems in the early stages of information processing, and are hence regarded as resulting from a failure of retrieval rather than encoding or storage. Brain SPECT disclosed a hypoperfusion of the right frontal cortex.
CONCLUSION—The data indicate that the cognitive profile is the result of a dysfunction of executive functions. This is corroborated by the finding of decreased blood flow in the right frontal cortex, and by evidence from the neuroanatomical literature. Thus the dysexecutive symptoms are thought to be caused by disconnection of the prefrontal cortex from the brainstem activating nuclei through the strategic localisation of the right thalamic infarction.

 PMID:9886448

  8. Mediodorsal thalamic nucleus receives a direct retinal input in marmoset monkey (Callithrix jacchus): a subunit B cholera toxin study.

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    de Sousa, Twyla Barros; de Santana, Melquisedec Abiaré Dantas; Silva, Alane de Medeiros; Guzen, Fausto Pierdoná; Oliveira, Francisco Gilberto; Cavalcante, Judney Cley; Cavalcante, Jeferson de Souza; Costa, Miriam Stela Maris Oliveira; Nascimento, Expedito Silva do

    2013-01-01

    The mediodorsal thalamic nucleus is a prominent nucleus in the thalamus, positioned lateral to the midline nuclei and medial to the intralaminar thalamic complex in the dorsal thalamus. Several studies identify the mediodorsal thalamic nucleus as a key structure in learning and memory, as well as in emotional mechanisms and alertness due to reciprocal connections with the limbic system and prefrontal cortex. Fibers from the retina to the mediodorsal thalamic nucleus have recently been described for the first time in a crepuscular rodent, suggesting a possible regulation of the mediodorsal thalamic nucleus by visual activity. The present study shows retinal afferents in the mediodorsal thalamic nucleus of a new world primate, the marmoset (Callithrix jacchus), using B subunit of cholera toxin (CTb) as an anterograde tracer. A small population of labeled retinofugal axonal arborizations is consistently labeled in small domains of the medial and lateral periphery of the caudal half of the mediodorsal nucleus. Retinal projections in the mediodorsal thalamic nucleus are exclusively contralateral and the morphology of the afferent endings was examined. Although the functional significance of this projection remains unknown, this retina-mediodorsal thalamic nucleus pathway may be involved in a wide possibility of functional implications.

  9. Determinación experimental de la tenacidad de fractura intralaminar en materiales compuestos laminados

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    Herráez Matesanz, Miguel

    2012-01-01

    Composite Materials are subject to a wide variety of damage modes. The most common damage modes are intralaminar cracking, delamination or interlaminar cracking, debonding fiber-matrix, and finally fiber breakage. All damage modes cause mechanical properties reduction. This is the case of intralaminar cracks, which are studied in this work. First, this research sets the matrix cracking problem of a composite laminate in terms of Fracture Mechanics throughout the introduction of the in-situ st...

  10. Thalamic semantic paralexia

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    Michael Hoffmann

    2012-03-01

    Full Text Available Alexia may be divided into different subtypes, with semantic paralexia being particularly rare. A 57 year old woman with a discreet left thalamic stroke and semantic paralexia is described. Language evalution with the Boston Diagnostic Aphasia Battery confirmed the semantic paralexia (deep alexia. Multimodality magnetic resonance imaging brain scanning excluded other cerebral lesions. A good recovery ensued.

  11. Thalamic semantic paralexia

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    Hoffmann, Michael

    2012-01-01

    Alexia may be divided into different subtypes, with semantic paralexia being particularly rare. A 57 year old woman with a discreet left thalamic stroke and semantic paralexia is described. Language evalution with the Boston Diagnostic Aphasia Battery confirmed the semantic paralexia (deep alexia). Multimodality magnetic resonance imaging brain scanning excluded other cerebral lesions. A good recovery ensued. PMID:22593810

  12. Thalamic alexia with agraphia

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    Fábio Henrique de Gobbi Porto

    2012-02-01

    Full Text Available Alexia with agraphia is defined as an acquired impairment affecting reading and writing ability. It can be associated with aphasia, but can also occur as an isolated entity. This impairment has classically been associated with a left angular gyrus lesion In the present study, we describe a case involving a patient who developed alexia with agraphia and other cognitive deficits after a thalamic hemorrhage. In addition, we discuss potential mechanisms of this cortical dysfunction syndrome caused by subcortical injury. We examined a patient who presented with alexia with agraphia and other cognitive deficits due to a hemorrhage in the left thalamus. Neuropsychological evaluation showed attention, executive function, arithmetic and memory impairments. In addition, language tests revealed severe alexia with agraphia in the absence of aphasia. Imaging studies disclosed an old thalamic hemorrhage involving the anterior, dorsomedial and pulvinar nuclei. Tractography revealed asymmetric thalamocortical radiations in the parietal region (left - right, and single photon emission computed tomography demonstrated hypoperfusion in the left thalamus that extended to the frontal and parietal cortices. Cortical cognitive deficits, including alexia with agraphia, may occur as the result of thalamic lesions. The probable mechanism is a diaschisis phenomenon involving thalamic tract disconnections.

  13. Thalamic alexia with agraphia.

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    de Gobbi Porto, Fábio Henrique; d'Ávila Freitas, Maria Isabel; de Oliveira, Maira Okada; Lucato, Leandro Tavares; Orsini, Marco; de Menezes, Sara Lúcia Silveira; Magaldi, Regina Miksian; Porto, Cláudia Sellitto; Dozzi Brucki, Sonia Maria; Nitrini, Ricardo

    2012-01-09

    Alexia with agraphia is defined as an acquired impairment affecting reading and writing ability. It can be associated with aphasia, but can also occur as an isolated entity. This impairment has classically been associated with a left angular gyrus lesion In the present study, we describe a case involving a patient who developed alexia with agraphia and other cognitive deficits after a thalamic hemorrhage. In addition, we discuss potential mechanisms of this cortical dysfunction syndrome caused by subcortical injury. We examined a patient who presented with alexia with agraphia and other cognitive deficits due to a hemorrhage in the left thalamus. Neuropsychological evaluation showed attention, executive function, arithmetic and memory impairments. In addition, language tests revealed severe alexia with agraphia in the absence of aphasia. Imaging studies disclosed an old thalamic hemorrhage involving the anterior, dorsomedial and pulvinar nuclei. Tractography revealed asymmetric thalamocortical radiations in the parietal region (left alexia with agraphia, may occur as the result of thalamic lesions. The probable mechanism is a diaschisis phenomenon involving thalamic tract disconnections.

  14. Thalamic alexia with agraphia

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    de Gobbi Porto, Fábio Henrique; d'Ávila Freitas, Maria Isabel; de Oliveira, Maira Okada; Lucato, Leandro Tavares; Orsini, Marco; de Menezes, Sara Lúcia Silveira; Magaldi, Regina Miksian; Porto, Cláudia Sellitto; Dozzi Brucki, Sonia Maria; Nitrini, Ricardo

    2012-01-01

    Alexia with agraphia is defined as an acquired impairment affecting reading and writing ability. It can be associated with aphasia, but can also occur as an isolated entity. This impairment has classically been associated with a left angular gyrus lesion In the present study, we describe a case involving a patient who developed alexia with agraphia and other cognitive deficits after a thalamic hemorrhage. In addition, we discuss potential mechanisms of this cortical dysfunction syndrome caused by subcortical injury. We examined a patient who presented with alexia with agraphia and other cognitive deficits due to a hemorrhage in the left thalamus. Neuropsychological evaluation showed attention, executive function, arithmetic and memory impairments. In addition, language tests revealed severe alexia with agraphia in the absence of aphasia. Imaging studies disclosed an old thalamic hemorrhage involving the anterior, dorsomedial and pulvinar nuclei. Tractography revealed asymmetric thalamocortical radiations in the parietal region (left alexia with agraphia, may occur as the result of thalamic lesions. The probable mechanism is a diaschisis phenomenon involving thalamic tract disconnections. PMID:22593808

  15. Ten deg off-axis tensile test for intralaminar shear characterization of fiber composites

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    Chamis, C. C.; Sinclair, J. H.

    1976-01-01

    A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the intralaminar shear characterization of unidirectional composites. Composite mechanics, a combined-stress failure criterion, and a finite element analysis were used to determine theoretically the stress-strain variation across the specimen width and the relative stress and strain magnitudes at the 10 deg plane. Strain gages were used to measure the strain variation across the specimen width at specimen midlength and near the end tabs. Specimens from Mod-I/epoxy, T-300/epoxy, and S-glass/epoxy were used in the experimental program. It was found that the 10 deg off-axis tensile test specimen is suitable for intralaminar shear characterization and it is recommended that it should be considered as a possible standard test specimen for such a characterization.

  16. Thalamic Lesions: A Radiological Review

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    Dimitri Renard

    2014-01-01

    Full Text Available Background. Thalamic lesions are seen in a multitude of disorders including vascular diseases, metabolic disorders, inflammatory diseases, trauma, tumours, and infections. In some diseases, thalamic involvement is typical and sometimes isolated, while in other diseases thalamic lesions are observed only occasionally (often in the presence of other typical extrathalamic lesions. Summary. In this review, we will mainly discuss the MRI characteristics of thalamic lesions. Identification of the origin of the thalamic lesion depends on the exact localisation inside the thalamus, the presence of extrathalamic lesions, the signal changes on different MRI sequences, the evolution of the radiological abnormalities over time, the history and clinical state of the patient, and other radiological and nonradiological examinations.

  17. Topography of thalamic projections requires attractive and repulsive functions of Netrin-1 in the ventral telencephalon.

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    Ashton W Powell

    2008-05-01

    Full Text Available Recent studies have demonstrated that the topography of thalamocortical (TC axon projections is initiated before they reach the cortex, in the ventral telencephalon (VTel. However, at this point, the molecular mechanisms patterning the topography of TC projections in the VTel remains poorly understood. Here, we show that a long-range, high-rostral to low-caudal gradient of Netrin-1 in the VTel is required in vivo for the topographic sorting of TC axons to distinct cortical domains. We demonstrate that Netrin-1 is a chemoattractant for rostral thalamic axons but functions as a chemorepulsive cue for caudal thalamic axons. In accordance with this model, DCC is expressed in a high-rostromedial to low-caudolateral gradient in the dorsal thalamus (DTh, whereas three Unc5 receptors (Unc5A-C show graded expression in the reverse orientation. Finally, we show that DCC is required for the attraction of rostromedial thalamic axons to the Netrin-1-rich, anterior part of the VTel, whereas DCC and Unc5A/C receptors are required for the repulsion of caudolateral TC axons from the same Netrin-1-rich region of the VTel. Our results demonstrate that a long-range gradient of Netrin-1 acts as a counteracting force from ephrin-A5 to control the topography of TC projections before they enter the cortex.

  18. A finite element modeling of posterior atlantoaxial fixation and biomechanical analysis of C2 intralaminar screw fixation

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    Ma Xuexiao; Peng Xianbo; Xiang Hongfei; Zhang Yan; Zhang Guoqing; Chen Bohua

    2014-01-01

    Background The objective of this study was to use three-dimensional finite element (FE) models to analyze the stability and the biomechanics of two upper cervical fixation methods:the C2 intralaminar screw method and the C2 pedicle screw method.Methods From computed tomography images,a nonlinear three-dimensional FE model from C0 (occiput) to C3 was developed with anatomic detail.The C2 intralaminar screw and the C2 pedicle screw systems were added to the model,in parallel to establish the interlaminar model and the pedicle model.The two models were operated with all possible states of motion and physiological loads to simulate normal movement.Results Both the C2 intralaminar screw method and the C2 pedicle screw method significantly reduced motion compared with the intact model.There were no statistically significant differences between the two methods.The Von Mises stresses of the internal and external laminar walls were similar between the two methods.Stability was also similar.Conclusions The C2 intralaminar screw method can complement but cannot completely replace the C2 pedicle screw method.Clinicians would need to assess and decide which approach to adopt for the best therapeutic effect.

  19. Complex neurological symptoms in bilateral thalamic stroke due to Percheron artery occlusion

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    Caruso, Paola; Manganotti, Paolo; Moretti, Rita

    2017-01-01

    The artery of Percheron is a rare anatomical variant where a single thalamic perforating artery arises from the proximal posterior cerebral artery (P1 segment) between the basilar artery and the posterior communicating artery and supplies the rostral mesencephalon and both paramedian territories of the thalami. Almost one-third of human brains present this variant. Occlusion of the artery of Percheron mostly results in a bilateral medial thalamic infarction, which usually manifests with altered consciousness (including coma), vertical gaze paresis, and cognitive disturbance. The presentation is similar to the “top of the basilar syndrome”, and early recognition should be prompted. We describe the case of a young female with this vessel variant who experienced a bilateral thalamic stroke. Magnetic resonance angiography demonstrated bilateral thalamic infarcts and a truncated artery of Percheron. Occlusion of the vessel was presumably due to embolism from a patent foramen ovale. Thrombolysis was performed, with incomplete symptom remission, cognitive impairment, and persistence of speech disorders. Early recognition and treatment of posterior circulation strokes is mandatory, and further investigation for underlying stroke etiologies is needed. PMID:28053539

  20. Thalamic metabolic alterations with cognitive dysfunction in idiopathic trigeminal neuralgia: a multivoxel spectroscopy study

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    Wang, Yuan; Bao, Faxiu; Ma, Shaohui; Guo, Chenguang; Jin, Chenwang; Zhang, Ming [First Affiliated Hospital of Xi' an Jiaotong University, Department of Medical Imaging, Xi' an, Shaanxi (China); Li, Dan [First Affiliated Hospital of Xi' an Jiaotong University, Department of Respiratory and Critical Care Medicine, Xi' an, Shaanxi (China)

    2014-08-15

    Although abnormalities in metabolite compositions in the thalamus are well described in patients with idiopathic trigeminal neuralgia (ITN), differences in distinct thalamic subregions have not been measured with proton magnetic resonance spectroscopy ({sup 1}H-MRS), and whether there are correlations between thalamic metabolites and cognitive function still remain unknown. Multivoxel MRS was recorded to investigate the metabolic alterations in the thalamic subregions of patients with ITN. The regions of interest were localized in the anterior thalamus (A-Th), intralaminar portion of the thalamus (IL-Th), posterior lateral thalamus (PL-Th), posterior medial thalamus (PM-Th), and medial and lateral pulvinar of the thalamus (PuM-Th and PuL-Th). The N-acetylaspartate to creatine (NAA/Cr) and choline to creatine (Cho/Cr) ratios were measured in the ITN and control groups. Scores of the visual analogue scale (VAS) and the Montreal Cognitive Assessment (MoCA) were analyzed to correlate with the neuroradiological findings. The NAA/Cr ratio in the affected side of PM-Th and PL-Th in ITN patients was statistically lower than that in the corresponding regions of the thalamus in controls. The NAA/Cr ratio in the affected PM-Th was negatively associated with VAS and disease duration. Furthermore, decreases of NAA/Cr and Cho/Cr were detected in the affected side of IL-Th, and lower Cho/Cr was positively correlated with MoCA values in the ITN group. Our result of low level of NAA/Cr in the affected PM-Th probably serves as a marker of the pain-rating index, and decreased Cho/Cr in IL-Th may be an indicator of cognitive disorder in patients with ITN. (orig.)

  1. Altered thalamic functional connectivity in multiple sclerosis

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    Liu, Yaou; Liang, Peipeng; Duan, Yunyun; Huang, Jing; Ren, Zhuoqiong; Jia, Xiuqin [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Dong, Huiqing; Ye, Jing [Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Shi, Fu-Dong [Department of Neurology and Tianjin Neurological Institute, Tianjin Medical University General Hospital, Tianjin 300052 (China); Butzkueven, Helmut [Department of Medicine, University of Melbourne, Parkville 3010 (Australia); Li, Kuncheng, E-mail: kunchengli55@gmail.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China)

    2015-04-15

    Highlights: •We demonstrated decreased connectivity between thalamus and cortical regions in MS. •Increased intra- and inter-thalamic connectivity was also observed in MS. •The increased functional connectivity is attenuated by increasing disease duration. -- Abstract: Objective: To compare thalamic functional connectivity (FC) in patients with multiple sclerosis (MS) and healthy controls (HC), and correlate these connectivity measures with other MRI and clinical variables. Methods: We employed resting-state functional MRI (fMRI) to examine changes in thalamic connectivity by comparing thirty-five patients with MS and 35 age- and sex-matched HC. Thalamic FC was investigated by correlating low frequency fMRI signal fluctuations in thalamic voxels with voxels in all other brain regions. Additionally thalamic volume fraction (TF), T2 lesion volume (T2LV), EDSS and disease duration were recorded and correlated with the FC changes. Results: MS patients were found to have a significantly lower TF than HC in bilateral thalami. Compared to HC, the MS group showed significantly decreased FC between thalamus and several brain regions including right middle frontal and parahippocampal gyri, and the left inferior parietal lobule. Increased intra- and inter-thalamic FC was observed in the MS group compared to HC. These FC alterations were not correlated with T2LV, thalamic volume or lesions. In the MS group, however, there was a negative correlation between disease duration and inter-thalamic connectivity (r = −0.59, p < 0.001). Conclusion: We demonstrated decreased FC between thalamus and several cortical regions, while increased intra- and inter-thalamic connectivity in MS patients. These complex functional changes reflect impairments and/or adaptations that are independent of T2LV, thalamic volume or presence of thalamic lesions. The negative correlation between disease duration and inter-thalamic connectivity could indicate an adaptive role of thalamus that is

  2. Comparison of Intralaminar and Interlaminar Mode-I Fracture Toughness of Unidirectional IM7/8552 Graphite/Epoxy Composite

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    Czabaj, Michael W.; Ratcliffe, James

    2012-01-01

    The intralaminar and interlaminar mode-I fracture-toughness of a unidirectional IM7/8552 graphite/epoxy composite were measured using compact tension (CT) and double cantilever beam (DCB) test specimens, respectively. Two starter crack geometries were considered for both the CT and DCB specimen configurations. In the first case, starter cracks were produced by 12.5 micron thick, Teflon film inserts. In the second case, considerably sharper starter cracks were produced by fatigue precracking. For each specimen configuration, use of the Teflon film starter cracks resulted in initially unstable crack growth and artificially high initiation fracture-toughness values. Conversely, specimens with fatigue precracks exhibited stable growth onset and lower initiation fracture toughness. For CT and DCB specimens with fatigue precracks, the intralaminar and interlaminar initiation fracture toughnesses were approximately equal. However, during propagation, the CT specimens exhibited more extensive fiber bridging, and rapidly increasing R-curve behavior as compared to the DCB specimens. Observations of initiation and propagation of intralaminar and interlaminar fracture, and the measurements of fracture toughness, were supported by fractographic analysis using scanning electron microscopy.

  3. Development of Rostral Prefrontal Cortex and Cognitive and Behavioural Disorders

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    Dumontheil, Iroise; Burgess, Paul W.; Blakemore, Sarah-Jayne

    2008-01-01

    Information on the development and functions of rostral prefrontal cortex (PFC), or Brodmann area 10, has been gathered from different fields, from anatomical development to functional neuroimaging in adults, and put forward in relation to three particular cognitive and behavioural disorders. Rostral PFC is larger and has a lower cell density in…

  4. Hypersexuality following bilateral thalamic infarction: case report.

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    Mutarelli, Eduardo G; Omuro, Antonio M P; Adoni, Tarso

    2006-03-01

    Hypersexuality is a rare but well recognized condition following brain injury. It has been described secondarily to dysfunction in the hypothalamus, the temporal and frontal lobes. We report a 63 year-old man that developed neuropsychological disturbances with hypersexuality as a prominent feature, disinhibition and moderate memory loss, hypersomnia and irritability after a bilateral paramedian thalamic infarction. A SPECT showed frontal hypoperfusion. We believe that these findings are expression of frontal-subcortical circuits dysfunction, particularly the orbitofrontal circuit, secondary to dorso medial thalamic infarction which probably plays a role in the determination of human sexual behavior. This case favors a thalamic modulation of frontal function.

  5. Preoperative shunts in thalamic tumours.

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    Goel A

    2000-10-01

    Full Text Available Thirty one patients with thalamic glioma underwent a pre-tumour resection shunt surgery. The procedure was uneventful in 23 patients with relief from symptoms of increased intracranial pressure. Eight patients worsened after the procedure. The level of sensorium worsened from excessively drowsy state to unconsciousness in seven patients. Three patients developed hemiparesis, 4 developed paresis of extra-ocular muscles and altered pupillary reflexes, and 1 developed incontinence of urine and persistent vomiting. Alteration in the delicately balanced intracranial pressure and movements in the tumour and vital adjacent brain areas could be the probable cause of the worsening in the neurological state in these 8 patients. On the basis of these observations and on review of literature, it is postulated that the ventricular dilatation following an obstruction in the path of the cerebrospinal fluid flow by a tumour could be a natural defense phenomenon of the brain.

  6. Cataleptic postures in thalamic hemorrhage: case report

    Directory of Open Access Journals (Sweden)

    Saposnik Gustavo

    2001-01-01

    Full Text Available We report a case of catalepsy associated with thalamic hemorrhage. A 72 year-old hypertensive woman had acute onset of right-sided weakness and speech disturbances. She was on anticoagulants because of aortic valve replacement. When postures were imposed, the patient maintained the left upper limb raised for several minutes, even in uncomfortable or bizarre positions. A CT scan of the head revealed a left thalamic hemorrhage. Cataleptic postures have been reported in few cases with acute stroke.

  7. Subcortical volume analysis in traumatic brain injury: the importance of the fronto-striato-thalamic circuit in task switching.

    Science.gov (United States)

    Leunissen, Inge; Coxon, James P; Caeyenberghs, Karen; Michiels, Karla; Sunaert, Stefan; Swinnen, Stephan P

    2014-02-01

    Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, ample evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus. To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions. Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit.

  8. Thalamic changes with mesial temporal sclerosis: MRI

    Energy Technology Data Exchange (ETDEWEB)

    Deasy, N.P.; Jarosz, J.M.; Cox, T.C.S. [Department of Neuroradiology, King' s College Hospital, London (United Kingdom); Elwes, R.C.D. [Department of Neurology, King' s College Hospital, London (United Kingdom); Polkey, C.E. [Department of Neurosurgery, King' s College and Maudsley Hospitals, London (United Kingdom)

    2000-05-01

    We reviewed the preoperative images of 28 patients with pathologically proven mesial temporal sclerosis, to assess thalamic asymmetry and signal change. A further 25 nonsurgical patients with temporal lobe epilepsy and unequivocal, unilateral changes of mesial temporal sclerosis, and 20 controls, were also reviewed. None of the control group had unequivocal asymmetry of the thalamus. There was an ipsilateral asymmetrically small thalamus in five (18 %) of the surgical group and in three (12 %) of the nonsurgical patients. In four cases there was thalamic signal change. In three patients with thalamic volume loss there was ipsilateral hemiatrophy. All patients with an asymmetrically small thalamus had an asymmetrically small fornix and all but one a small ipsilateral mamillary body. (orig.)

  9. Thalamic Bursts Down-regulate Cortical Theta and Nociceptive Behavior.

    Science.gov (United States)

    LeBlanc, Brian W; Cross, Brent; Smith, Kelsey A; Roach, Catherine; Xia, Jimmy; Chao, Yu-Chieh; Levitt, Joshua; Koyama, Suguru; Moore, Christopher I; Saab, Carl Y

    2017-05-30

    We tested the relation between pain behavior, theta (4-8 Hz) oscillations in somatosensory cortex and burst firing in thalamic neurons in vivo. Optically-induced thalamic bursts attenuated cortical theta and mechanical allodynia. It is proposed that thalamic bursts are an adaptive response to pain that de-synchronizes cortical theta and decreases sensory salience.

  10. Evolution of mammalian sensorimotor cortex: Thalamic projections to parietal cortical areas in Monodelphis domestica

    Directory of Open Access Journals (Sweden)

    James Clinton Dooley

    2015-01-01

    Full Text Available The current experiments build upon previous studies designed to reveal the network of parietal cortical areas present in the common mammalian ancestor. Understanding this ancestral network is essential for highlighting the basic somatosensory circuitry present in all mammals, and how this basic plan was modified to generate species specific behaviors. Our animal model, the short-tailed opossum (Monodelphis domestica, is a South American marsupial that has been proposed to have a similar ecological niche and morphology to the earliest common mammalian ancestor. In this investigation, we injected retrograde neuroanatomical tracers into the face and body representations of primary somatosensory cortex (S1, the rostral and caudal somatosensory fields (SR and SC, as well as a multimodal region (MM. Projections from different architectonically defined thalamic nuclei were then quantified. Our results provide further evidence to support the hypothesized basic mammalian plan of thalamic projections to S1, with the lateral and medial ventral posterior thalamic nuclei (VPl and VPm projecting to S1 body and S1 face, respectively. Additional strong projections are from the medial division of posterior nucleus (Pom. SR receives projections from several midline nuclei, including the medial dorsal, ventral medial nucleus, and Pom. SC and MM show similar patterns of connectivity, with projections from the ventral anterior and ventral lateral nuclei, VPm and VPl, and the entire posterior nucleus (medial and lateral. Notably, MM is distinguished from SC by relatively dense projections from the dorsal division of the lateral geniculate nucleus and pulvinar. We discuss the finding that S1 of the short-tailed opossum has a similar pattern of projections as other marsupials and mammals, but also some distinct projections not present in other mammals. Further we provide additional support for a primitive posterior parietal cortex which receives input from multiple

  11. Language disturbances from mesencephalo-thalamic infarcts. Identification of thalamic nuclei by CT-reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarino, L.G.; Nicolai, A.; Valassi, F. (Ospedale Civile di Gorizia (Italy). Div. di Neurologia); Biasizzo, E. (Ospedale di Udine (Italy). Servizio di Neuroradiologia)

    1991-08-01

    The authors report the cases of two patients with CT-documented paramedian mesencephalo-thalamic infarcts, showing language disturbances. The first patient showed a non fluent, transcortical motor-like aphasia, the other had a fluent but severely paraphasic language disorder. The CT study disclosed that it was the dorso-median thalamic nucleus that was mostly involved in both cases. These findings agree with a few previous pathological studies suggesting that the paramedian thalamic nuclei, particlularly the dorso-median nucleus may play some role in language disturbances. However the anatomical basis for thalamic aphasia remains speculative, taking into account the importantce of cortical connections in the origin of subcortical neuropsychological disturbances. (orig.).

  12. Thalamic pain alleviated by stellate ganglion block

    Science.gov (United States)

    Liao, Chenlong; Yang, Min; Liu, Pengfei; Zhong, Wenxiang; Zhang, Wenchuan

    2017-01-01

    Abstract Rationale: Thalamic pain is a distressing and treatment-resistant type of central post-stroke pain. Although stellate ganglion block is an established intervention used in pain management, its use in the treatment of thalamic pain has never been reported. Patient concerns: A 66-year-old woman presented with a 3-year history of severe intermittent lancinating pain on the right side of the face and the right hand. The pain started from the ulnar side of the right forearm after a mild ischemic stroke in bilateral basal ganglia and left thalamus. Weeks later, the pain extended to the dorsum of the finger tips and the whole palmar surface, becoming more severe. Meanwhile, there was also pain with similar characteristics emerging on her right face, resembling atypical trigeminal neuralgia. Diagnoses: Thalamic pain was diagnosed. Interventions: After refusing the further invasive treatment, she was suggested to try stellate ganglion block. Outcomes: After a 3-day period of pain free (numerical rating scale: 0) postoperatively, she reported moderate to good pain relief with a numerical rating scale of about 3 to 4 lasting 1 month after the first injection. Pain as well as the quality of life was markedly improved with less dose of analgesic agents. Lessons: Stellate ganglion block may be an optional treatment for thalamic pain. PMID:28151918

  13. Morphological Abnormalities of Thalamic Subnuclei in Migraine

    DEFF Research Database (Denmark)

    Magon, Stefano; May, Arne; Stankewitz, Anne

    2015-01-01

    techniques in substantial patient populations are lacking. In the present study, we investigated changes of thalamic volume and shape in a large multicenter cohort of patients with migraine. High-resolution T1-weighted MRI data acquired at 3 tesla in 131 patients with migraine (38 with aura; 30.8 ± 9 years...

  14. Receptive field properties of trigeminothalamic neurons in the rostral trigeminal sensory nuclei of cats.

    Science.gov (United States)

    Ro, J Y; Capra, N F

    1994-01-01

    This study described topographic and receptive field representation in the region of the rostral trigeminal nuclei, and evaluated whether thalamic neurons from the principal sensory nucleus relay muscle afferent information to the thalamus. Extracellular single-unit activity was recorded from anesthetized cats. Units were tested for responses to natural stimuli (i.e., air bursts, brushing, light pressure, and pinch) applied to the face and oral cavity, electrical stimulation of the masseter nerve, and ramp-and-hold movements of the jaw. The receptive fields and physiological properties for 110 units were studied; we were able to verify the recording site for 96 of these units. Most of the units had discrete receptive fields in the oral cavity, skin, hair, and masseter muscle. Only 2 units received convergent inputs. Stimulation of the ipsilateral and contralateral ventroposteromedial nucleus of the thalamus was performed to identify antidromically activated units. The results showed that the dorsal principal sensory nucleus received its input primarily from the oral cavity. Most of the units (85%) that were activated by antidromic stimulation from the ipsilateral thalamus were located in this nucleus. In contrast, 82% of the units that projected to the contralateral thalamus were located in the ventral principal sensory nucleus. A complete somatotopic representation of the ipsilateral face and oral cavity was observed in the ventral principal sensory nucleus. Although 24 units had muscle receptive fields, none were activated by stimulation of the ipsilateral thalamus, and only 1 responded to stimulation of the contralateral thalamus. Most of the units that were not antidromically driven were recorded outside of the cytoarchitectural boundaries of the principal sensory nucleus. Retrograde labeling of the rostral trigeminal nuclei indicated that most of the neurons in the dorsal principal sensory nucleus projected to the ipsilateral thalamus, whereas those in the

  15. Hypersexuality following bilateral thalamic infarction: case report

    OpenAIRE

    Mutarelli Eduardo G; Omuro Antonio M.P.; Adoni Tarso

    2006-01-01

    Hypersexuality is a rare but well recognized condition following brain injury. It has been described secondarily to dysfunction in the hypothalamus, the temporal and frontal lobes. We report a 63 year-old man that developed neuropsychological disturbances with hypersexuality as a prominent feature, disinhibition and moderate memory loss, hypersomnia and irritability after a bilateral paramedian thalamic infarction. A SPECT showed frontal hypoperfusion. We believe that these findings are expre...

  16. Functional connectivity of the human rostral and caudal cingulate motor areas in the brain resting state at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Christophe [CHNO des Quinze-Vingts, UPMC Paris 6, Service de NeuroImagerie, Paris (France)

    2010-01-15

    Three cingulate motor areas have been described in monkeys, the rostral, dorsal, and ventral cingulate motor areas, and would control limbic-related motor activity. However, little anatomical data are available in human about the functional networks these cingulate areas underlie. Therefore, networks anchored in the rostral and caudal cingulate motor areas (rCMA and cCMA, respectively) were studied in human using functional connectivity during the brain resting state. Since the rCMA and cCMA are located just under the pre-supplementary and supplementary motor areas (pre-SMA and SMA), the pre-SMA- and SMA-centered networks were also studied to ensure that these four circuits were correctly dissociated. Data from 14 right-handed healthy volunteers were acquired at rest and analyzed by region of interest (ROI)-based functional connectivity. The blood oxygenation level-dependent (BOLD) signal fluctuations of separate ROIs located in rCMA, cCMA, pre-SMA, and SMA were successively used to identify significant temporal correlations with BOLD signal fluctuations of other brain regions. Low-frequency BOLD signal of the CMA was correlated with signal fluctuations in the prefrontal, cingulate, insular, premotor, motor, medial and inferior parietal cortices, putamen and thalamus, and anticorrelated with the default-mode network. rCMA was more in relation with prefrontal, orbitofrontal, and language-associated cortices than cCMA more related to sensory cortex. These cingulate networks were very similar to the pre-SMA- and SMA-centered networks, although pre-SMA and SMA showed stronger correlation with the prefrontal and inferior parietal cortices and with the cerebellum and the superior parietal cortex, respectively. The human cingulate motor areas constitute an interface between sensorimotor, limbic and executive systems, sharing common cortical, striatal, and thalamic relays with the overlying premotor medial areas. (orig.)

  17. Neurological manifestations and PET studies of the thalamic vascular lesions

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Shinji; Kawamura, Mitsuru; Hirayama, Keizo [Chiba Univ. (Japan). School of Medicine

    1995-02-01

    We divided 38 patients with cerebrovascular disease of the thalamus into 5 groups according to the site of the thalamic lesions as confirmed by X-ray CT and/or MRI. In 16 patients, we examined the cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) by positron emission tomography (PET). In the anteromedial thalamic lesion group, patients displayed disturbances of spontaneity, memory, reading and writing. CBF and CMRO{sub 2} were decreased in the frontal, parietal and temporal lobes on the side of the lesion. In the dorsolateral thalamic lesion group, ataxic hemiparesis was a characteristic symptom. CBF and CMRO{sub 2} were decreased in frontoparietal lobes on the side of the lesion. In the group with lesions confined to the nucleus ventralis posterioris thalami, the main symptoms were sensory disturbance, with cheiro-oral sensory syndrome being particularly evident. CBF and CMRO{sub 2} were decreased in the parietal lobe on the side of the lesion. In the group with posterolateral thalamic lesions without pulvinar involvement, patients exhibited thalamic syndrome without thalamic pain. CBF and CMRO{sub 2} were decreased in the frontoparietal and temporal lobes on the side of the lesion. In contrast, in the group with posterolateral thalamic lesions with pulvinar involvement, all patients showed thalamic pain. The decrease in CBF and CMRO{sub 2} extended to the inferomedial region of the temporal lobe in addition to the area of decreased CBF and CMRO{sub 2} observed in the group with posterolateral thalamic lesions without pulvinar involvement. Based on these results, we speculate that the neurological manifestations of thalamic vascular disease are associated with a decrease in cortical CBF and CMRO{sub 2} secondary to the thalamic lesions. (author).

  18. Expression of 10 GABA(A) receptor subunit messenger RNAs in the motor-related thalamic nuclei and basal ganglia of Macaca mulatta studied with in situ hybridization histochemistry.

    Science.gov (United States)

    Kultas-Ilinsky, K; Leontiev, V; Whiting, P J

    1998-07-01

    In situ hybridization histochemistry technique with [35S]UTP-labelled riboprobes was used to study the expression pattern of 10 GABA(A) receptor subunit messenger RNAs in the basal ganglia and motor thalamic nuclei of rhesus monkey. Human transcripts were used for the synthesis of alpha2, alpha4, beta2, beta3, gamma1 and delta subunit messenger RNA probes. Rat complementary DNAs were used for generating alpha1, alpha3, beta1 and gamma2 subunit messenger RNA probes. Nigral, pallidal and cerebellar afferent territories in the ventral tier thalamic nuclei all expressed alpha1, alpha2, alpha3, alpha4, beta1, beta2, beta3, delta and gamma2 subunit messenger RNAs but at different levels. Each intralaminar nucleus displayed its own unique expression pattern. In the thalamus, gamma1 subunit messenger RNA was detected only in the parafascicular nucleus. Comparison of the expression patterns with the known organization of GABA(A) connections in thalamic nuclei suggests that (i) the composition of the receptor associated with reticulothalamic synapses, except for those in the intralaminar nuclei, may be alpha1alpha4beta2delta, (ii) receptors of various other subunit compositions may operate in the local GABAergic circuits, and (iii) the composition of receptors at nigro- and pallidothalamic synapses may differ, with those at nigrothalamic probably containing beta1 and gamma2 subunits. In the medial and lateral parts of the globus pallidus, the subthalamic nucleus and the substantia nigra pars reticularis, the alpha1, beta2 and gamma2 messenger RNAs were co-expressed at a high level suggesting that this subunit composition was associated with all GABAergic synapses in the direct and indirect striatal output pathways. Various other subunit messenger RNAs were also expressed but at a lower level. In the substantia nigra pars compacta the most highly expressed messenger RNAs were alpha3, alpha4 and beta3; all other subunit messenger RNAs studied, except for gamma1, alpha1 and

  19. A tall rostral hook in a medieval horse premolar tooth.

    Science.gov (United States)

    Viranta, Suvi; Mannermaa, Kristiina

    2017-06-01

    Development of dental abnormalities due to improper occlusal wear is common among modern domestic horses. This phenomenon often is attributed to jaw conformation. Rostral mandibular hooks may develop in horses with underjet or mandibular prognathism, a condition where the lower jaw protrudes forward, beyond the upper jaw. Less abrasive diet, free of phytoliths and matrix-like plant fibers, also may promote enamel and focal overgrowths of equine dentition. Here we report a rostral mandibular hook in a lower premolar tooth of a medieval horse, found in a spring deposit in Levänluhta, Osthrobothnia, Finland. To our knowledge, this is the first such report from a medieval horse. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. MR imaging of psychosurgery: rostral atrophy following stereotacic subcaudate tractotomy.

    Science.gov (United States)

    Cauley, K A; Waheed, W; Salmela, M; Filippi, C G

    2010-11-01

    There are few reports of MR imaging findings following psychosurgery. Here, we report the findings of 3T MR imaging of the sequelae of stereotactic subcaudate tractotomy (SST). Rostral atrophy is noted on conventional imaging. Diffusion tensor (DT) tractography demonstrated no communicating white matter tracts between the inferior frontal lobes, which appeared normally as thick fibre bundles in age-matched controls. DT tractography provides a unique tool for the evaluation of sequelae of ablative psychosurgical procedures.

  1. [Increased level of Gerstmann's syndrome secondary to thalamic hematoma].

    Science.gov (United States)

    Casado, J L; Jarrín, S; Madrid, A; Gil-Peralta, A

    1995-01-01

    A patient developed enlarged Gerstmann syndrome after left thalamic haematoma. Single photon emission computerised tomography (SPECT) showed left parietal-temporal cortical hypocapture. These findings would lead us to believe that the clinical picture of our patient was due to a thalamic-cortical diaschitic phenomenon.

  2. Dengue fever with unusual thalamic involvement.

    Science.gov (United States)

    Mallick, Asim Kumar; Purkait, Radheshyam; Sinhamahapatra, Tapan Kumar

    2012-01-01

    Dengue is the most important mosquito-borne viral disease in the world and is caused by four distinct viruses (type 1 to 4) that are closely related antigenically. Infection by dengue virus may be asymptomatic or may lead to undifferentiated fever, dengue fever or dengue haemorrhagic fever. Recent observations indicate that the clinical profile of dengue is changing and the neurological complications are being reported more frequently. The neurological features includeheadache, seizures, neck stiffness, depressed sensorium, behavioural disorders, delirium, paralysis and cranial nerve palsies. Such neurological symptoms in dengue fever wereattributed to cerebral oedema, haemorrhage, haemoconcentration due to increasing vascular permeability, coagulopathy and release of toxic substances. Cerebral oedema, encephalitis-like changes (oedema and scattered focal lesions), intracranial haemorrhages as well as selective involvement of bilateral hippocampus in dengue infection have been reported previously on selective neuro-imaging but thalamic involvement is rare. We here report a case of a typical presentation of encephalopathy with left sided complete hemiplegia due to thalamic involvement in dengue infection.

  3. Central Thalamic Deep-Brain Stimulation Alters Striatal-Thalamic Connectivity in Cognitive Neural Behavior.

    Science.gov (United States)

    Lin, Hui-Ching; Pan, Han-Chi; Lin, Sheng-Huang; Lo, Yu-Chun; Shen, Elise Ting-Hsin; Liao, Lun-De; Liao, Pei-Han; Chien, Yi-Wei; Liao, Kuei-Da; Jaw, Fu-Shan; Chu, Kai-Wen; Lai, Hsin-Yi; Chen, You-Yin

    2015-01-01

    Central thalamic deep brain stimulation (CT-DBS) has been proposed as an experimental therapeutic approach to produce consistent sustained regulation of forebrain arousal for several neurological diseases. We investigated local field potentials (LFPs) induced by CT-DBS from the thalamic central lateral nuclei (CL) and the striatum as potential biomarkers for the enhancement of lever-pressing skill learning. LFPs were simultaneously recorded from multiple sites in the CL, ventral striatum (Vstr), and dorsal striatum (Dstr). LFP oscillation power and functional connectivity were assessed and compared between the CT-DBS and sham control groups. The theta and alpha LFP oscillations were significantly increased in the CL and striatum in the CT-DBS group. Furthermore, interhemispheric coherences between bilateral CL and striatum were increased in the theta band. Additionally, enhancement of c-Fos activity, dopamine D2 receptor (Drd2), and α4-nicotinic acetylcholine receptor (α4-nAChR) occurred after CT-DBS treatment in the striatum and hippocampus. CT-DBS strengthened thalamic-striatal functional connectivity, which demonstrates that the inter-regional connectivity enhancement might contribute to synaptic plasticity in the striatum. Altered dopaminergic and cholinergic receptors resulted in modulation of striatal synaptic plasticity's ability to regulate downstream signaling cascades for higher brain functions of lever-pressing skill learning.

  4. Central Thalamic Deep-Brain Stimulation Alters Striatal–Thalamic Connectivity in Cognitive Neural Behavior

    Directory of Open Access Journals (Sweden)

    Hui-Ching eLin

    2016-01-01

    Full Text Available Central thalamic deep brain stimulation (CT-DBS has been proposed as an experimental therapeutic approach to produce consistent sustained regulation of forebrain arousal for several neurological diseases. We investigated local field potentials (LFPs induced by CT-DBS from the thalamic central lateral nuclei (CL and the striatum as potential biomarkers for the enhancement of lever-pressing skill learning. LFPs were simultaneously recorded from multiple sites in the CL, ventral striatum (Vstr, and dorsal striatum (Dstr. LFP oscillation power and functional connectivity were assessed and compared between the CT-DBS and sham control groups. The theta and alpha LFP oscillations were significantly increased in the CL and striatum in the CT-DBS group. Furthermore, interhemispheric coherences between bilateral CL and striatum were increased in the theta band. Additionally, enhancement of c-Fos activity, dopamine D2 receptor (Drd2 and 4-nicotinic acetylcholine receptor (4-nAChR occurred after CT-DBS treatment in the striatum and hippocampus. CT-DBS strengthened thalamic-striatal functional connectivity, which demonstrates that the inter-regional connectivity enhancement might contribute to synaptic plasticity in the striatum. Altered dopaminergic and cholinergic receptors resulted in modulation of striatal synaptic plasticity’s ability to regulate downstream signaling cascades for higher brain functions of lever-pressing skill learning.

  5. Location of the rostral end of the longitudinal brain axis: review of an old topic in the light of marking experiments on the closing rostral neuropore.

    Science.gov (United States)

    Puelles, L; Domenech-Ratto, G; Martinez-de-la-Torre, M

    1987-11-01

    The rostral end of the forebrain was classically defined on the basis of descriptive data. Different assumptions on the mode of closure of the rostral neuropore caused three different theories of the rostral end of the forebrain to be formulated (His 1893a; von Kupffer, '06; Johnston, '09). Some recent descriptive and experimental data have put these theories into question. A piece of black nylon thread was inserted through the rostral neuropore of chick embryos and was fixed to its ventral lip. These operations were done at all intermediate stages during the process of closure of the rostral neuropore. The embryos were sacrificed at a later stage, by which time the neuropore had disappeared. In the cleared specimens the threads always lay at the same site, namely the upper border of lamina terminalis, irrespective of the stage at which the marker was inserted. These results stand against His's conception (1893a,b) of a sutura terminalis and support the single mechanism of sutura dorsalis during closure of the rostral neuropore. The marking data therefore imply that the topologic rostral end of the forebrain lies at the upper limit of lamina terminalis, as proposed by von Kupffer, '06).

  6. Isolated thalamic tuberculoma presenting as ataxic hemiparesis

    Science.gov (United States)

    Sahu, Ritesh; Patil, Tushar B; Kori, Prakash; Shukla, Rakesh

    2013-01-01

    Lacunar syndrome is a neurodeficit secondary to a deep cerebral lesion, usually because of microatheroma of small arteries. Ataxic hemiparesis (AH) is a lacunar syndrome with unilateral pyramidal weakness and ipsilateral ataxia. Thalamic tuberculoma, as a cause of AH, has not been previously described in the literature. We describe an elderly man who presented with left hemiparesis and ipsilateral ataxia. Clinical examination revealed upper motor neuron left facial paresis and left-sided hemiparesis. The patient had incoordination in left upper and lower limbs. Mantoux test was positive and erythrocyte sedimentation rate was elevated. MRI of brain showed a conglomerated hypointense lesion in the right thalamus with a peripheral hyperintensity on T1-weighted imaging and a hyperintense lesion in T2-weighted imaging with significant perilesional oedema, suggesting a tuberculoma. The patient was treated with antitubercular therapy and was symptomatically better at the 9 months follow-up. PMID:23580686

  7. Hypersexuality and dysexecutive syndrome after a thalamic infarct.

    Science.gov (United States)

    Spinella, Marcello

    2004-12-01

    Hypersexuality can result from insults to several neuroanatomical structures that regulate sexual behavior. A case is presented of an adult male with a thalamic infarct resulting in a paramedian thalamic syndrome, consisting of hypersomnolence, confabulatory anterograde amnesia (including reduplicative paramnesia), vertical gaze deficits, and hypophonic speech. A dysexecutive syndrome also manifested, consisting of social disinhibition, apathy, witzelsucht, motor inhibition deficits, and environmental dependence. Hypersexuality uncharacteristic of his premorbid behavior was evident in instances of exhibitionism, public masturbation, and verbal sexual obscenities. In contrast to the few previous reports of hypersexuality following thalamic infarct, this case neither involved mania nor hemichorea. The relevance of the mediodorsal thalamic nucleus in limbic and prefrontal circuits is discussed.

  8. Vivax malaria:a rare cause of thalamic bleed

    Institute of Scientific and Technical Information of China (English)

    Jaydeep Sarkar; Biku Naik; Atul Gawande; Atul Goel

    2012-01-01

    Most common cause of thalamic bleed is hypertension; other causes are arteriovenous malformation, aneurysm, bleeding diathesis, drugs, amyloid angiopathy, tumor etc.We present a case ofPlasmodium vivax (P. vivax) malaria with unusual site of bleeding i.e. left thalamus of brain.To the best of our knowledge, this is the first reported case of thalamic bleed caused by vivax malaria in absence of severe thrombocytopenia/disseminated intravascular coagulation (DIC).

  9. Cocaine dependence and thalamic functional connectivity: a multivariate pattern analysis

    Directory of Open Access Journals (Sweden)

    Sheng Zhang

    2016-01-01

    Full Text Available Cocaine dependence is associated with deficits in cognitive control. Previous studies demonstrated that chronic cocaine use affects the activity and functional connectivity of the thalamus, a subcortical structure critical for cognitive functioning. However, the thalamus contains nuclei heterogeneous in functions, and it is not known how thalamic subregions contribute to cognitive dysfunctions in cocaine dependence. To address this issue, we used multivariate pattern analysis (MVPA to examine how functional connectivity of the thalamus distinguishes 100 cocaine-dependent participants (CD from 100 demographically matched healthy control individuals (HC. We characterized six task-related networks with independent component analysis of fMRI data of a stop signal task and employed MVPA to distinguish CD from HC on the basis of voxel-wise thalamic connectivity to the six independent components. In an unbiased model of distinct training and testing data, the analysis correctly classified 72% of subjects with leave-one-out cross-validation (p < 0.001, superior to comparison brain regions with similar voxel counts (p < 0.004, two-sample t test. Thalamic voxels that form the basis of classification aggregate in distinct subclusters, suggesting that connectivities of thalamic subnuclei distinguish CD from HC. Further, linear regressions provided suggestive evidence for a correlation of the thalamic connectivities with clinical variables and performance measures on the stop signal task. Together, these findings support thalamic circuit dysfunction in cognitive control as an important neural marker of cocaine dependence.

  10. Intramedullary projections of the rostral nucleus of the solitary tract in the rat : Gustatory influences on autonomic output

    NARCIS (Netherlands)

    Streefland, C; Jansen, K

    1999-01-01

    The efferent connections of the rostral nucleus of the solitary tract (NTS) in the rat were studied by anterograde transport of Phaseolus vulgaris leucoagglutinin. Rostral to the injection site, fibers travel through the rostral parvocellular reticular formation and deflect medially or laterally aro

  11. Thalamic mediation of hypoxic respiratory depression in lambs.

    Science.gov (United States)

    Koos, Brian J; Rajaee, Arezoo; Ibe, Basil; Guerra, Catalina; Kruger, Lawrence

    2016-04-01

    Immaturity of respiratory controllers in preterm infants dispose to recurrent apnea and oxygen deprivation. Accompanying reductions in brain oxygen tensions evoke respiratory depression, potentially exacerbating hypoxemia. Central respiratory depression during moderate hypoxia is revealed in the ventilatory decline following initial augmentation. This study determined whether the thalamic parafascicular nuclear (Pf) complex involved in adult nociception and sensorimotor regulation (Bentivoglio M, Balerecia G, Kruger L. Prog Brain Res 87: 53-80, 1991) also becomes a postnatal controller of hypoxic ventilatory decline. Respiratory responses to moderate isocapnic hypoxia were studied in conscious lambs. Hypoxic ventilatory decline was compared with peak augmentation. Pf and/or adjacent thalamic structures were destroyed by the neuron-specific toxin ibotenic acid (IB). IB lesions involving the thalamic Pf abolished hypoxic ventilatory decline. Lesions of adjacent thalamic nuclei that spared Pf and control injections of vehicle failed to blunt hypoxic respiratory depression. Our findings reveal that the thalamic Pf region is a critical controller of hypoxic ventilatory depression and thus a key target for exploring molecular concomitants of forebrain pathways regulating hypoxic ventilatory depression in early development.

  12. UP states protect ongoing cortical activity from thalamic inputs.

    Directory of Open Access Journals (Sweden)

    Brendon O Watson

    Full Text Available Cortical neurons in vitro and in vivo fluctuate spontaneously between two stable membrane potentials: a depolarized UP state and a hyperpolarized DOWN state. UP states temporally correspond with multineuronal firing sequences which may be important for information processing. To examine how thalamic inputs interact with ongoing cortical UP state activity, we used calcium imaging and targeted whole-cell recordings of activated neurons in thalamocortical slices of mouse somatosensory cortex. Whereas thalamic stimulation during DOWN states generated multineuronal, synchronized UP states, identical stimulation during UP states had no effect on the subthreshold membrane dynamics of the vast majority of cells or on ongoing multineuronal temporal patterns. Both thalamocortical and corticocortical PSPs were significantly reduced and neuronal input resistance was significantly decreased during cortical UP states -- mechanistically consistent with UP state insensitivity. Our results demonstrate that cortical dynamics during UP states are insensitive to thalamic inputs.

  13. Global suppression of electrocortical activity in unilateral perinatal thalamic stroke.

    LENUS (Irish Health Repository)

    Kharoshankaya, Liudmila

    2014-07-01

    We present an unusual case of persistent generalized electroencephalography (EEG) suppression and right-sided clonic seizures in a male infant born at 40(+2) weeks\\' gestation, birthweight 3240g, with an isolated unilateral thalamic stroke. The EEG at 13 hours after birth showed a generalized very low amplitude background pattern, which progressed to frequent electrographic seizures over the left hemisphere. The interictal background EEG pattern remained grossly abnormal over the next 48 hours, showing very low background amplitudes (<10μV). Magnetic resonance imaging revealed an isolated acute left-sided thalamic infarction. This is the first description of severe global EEG suppression caused by an isolated unilateral thalamic stroke and supports the role of the thalamus as the control centre for cortical electrical activity.

  14. Thalamic circuit mechanisms link sensory processing in sleep and attention

    Directory of Open Access Journals (Sweden)

    Zhe eChen

    2016-01-01

    Full Text Available The correlation between sleep integrity and attentional performance is normally interpreted as poor sleep causing impaired attention. Here, we provide an alternative explanation for this correlation: common thalamic circuits regulate sensory processing across sleep and attention, and their disruption may lead to correlated dysfunction. Using multi-electrode recordings in mice, we find that rate and rhythmicity of thalamic reticular nucleus (TRN neurons are predictive of their functional organization in sleep and suggestive of their participation in sensory processing across states. Surprisingly, TRN neurons associated with spindles in sleep are also associated with alpha oscillations during attention. As such, we propose that common thalamic circuit principles regulate sensory processing in a state-invariant manner and that in certain disorders, targeting these circuits may be a more viable therapeutic strategy than considering individual states in isolation.

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  3. Bilateral thalamic infarction with psychiatric symptoms: case report

    Directory of Open Access Journals (Sweden)

    Betül Tekin Güveli

    2016-04-01

    Full Text Available Introduction: Thalamus is a mass of gray matter, which plays a role in the transmission of sensory and motor information to the primary sensory and motor centers of the cerebral cortex, cerebellum and basal ganglia. Vascular lesions of thalamus may occur in different syndromes depending on the affected nuclei. In this report, a case with acute evolving personality and behavior changes and detected bilateral thalamic infarction will be presented. Case: A 40-year-old male patient was brought to the psychiatric ER with complaints of acute excessive sleep and behavioral changing. His neurological examination was normal except for limited cooperation and dysarthria. There was hyperintensity in bilateral paramedian thalamic regions in diffusion MRI and hypointensity in the right side in the ADC. During clinical observation the patient occasionally had visual hallucinations and attempted suicide. The psychiatrist diagnosed the patient with psychotic disorder due to his general medical condition and olanzapine 10 mg / day was prescribed. Etiological tests were normal. The patient was discharged after clinical improvement on the tenth day of hospitalization. Conclusion: Bilateral thalamic infarcts are very rare in all ischemic cerebrovascular diseases and typically result in changing of consciousness, gaze palsy and memory. The most common etiological cause of bilateral thalamic infarct is cardioembolism and the prognosis is generally good. Thalamic infarcts have a clinical spectrum varying according to the location of the lesion and may even just be present with psychiatric symptoms. In acute or subacute personality and behavior changes in a patient with no history of psychiatric disorders, thalamic lesions should be considered.

  4. Pulsatile compression of the rostral ventrolateral medulla in hypertension.

    Science.gov (United States)

    Morimoto, S; Sasaki, S; Miki, S; Kawa, T; Itoh, H; Nakata, T; Takeda, K; Nakagawa, M; Naruse, S; Maeda, T

    1997-01-01

    The rostral ventrolateral medulla (RVLM) has been known to be a major regulating center of sympathetic and cardiovascular activities. An association between essential hypertension and neurovascular compression of the RVLM has been reported in clinical observations, including magnetic resonance imaging (MRI) studies. To reconfirm this relationship, we performed MRI using a high-resolution 512 x 512 matrix in patients with essential and secondary hypertension and in normotensive subjects. The duration of hypertension and the degree of organ damage by hypertension were not significantly different between the two hypertension groups. Neurovascular compression of the RVLM was observed in 74% of the essential hypertension group, and the incidence of compression was significantly higher than in the secondary hypertension group (11%) or in the normotensive group (13%) (P model has already been reported, its underlying mechanism is not well known. Accordingly, we performed experiments to investigate whether pulsatile compression of the RVLM would increase arterial pressure and to elucidate the mechanism of the pressor response in rats. Sympathetic nerve activity, arterial pressure, heart rate, and plasma levels of epinephrine and norepinephrine were increased by pulsatile compression of the RVLM. The pressor response was abolished by intravenous treatment with hexamethonium or RVLM injection of kainic acid. In summary, the results from the MRI studies suggest that neurovascular compression of the RVLM is, at least in part, causally related to essential hypertension. This was supported by the results from experimental studies using rats indicating that pulsatile compression of the RVLM increases arterial pressure by enhancing sympathetic outflow.

  5. A thalamic reticular networking model of consciousness

    Directory of Open Access Journals (Sweden)

    Min Byoung-Kyong

    2010-03-01

    Full Text Available Abstract [Background] It is reasonable to consider the thalamus a primary candidate for the location of consciousness, given that the thalamus has been referred to as the gateway of nearly all sensory inputs to the corresponding cortical areas. Interestingly, in an early stage of brain development, communicative innervations between the dorsal thalamus and telencephalon must pass through the ventral thalamus, the major derivative of which is the thalamic reticular nucleus (TRN. The TRN occupies a striking control position in the brain, sending inhibitory axons back to the thalamus, roughly to the same region where they receive afferents. [Hypotheses] The present study hypothesizes that the TRN plays a pivotal role in dynamic attention by controlling thalamocortical synchronization. The TRN is thus viewed as a functional networking filter to regulate conscious perception, which is possibly embedded in thalamocortical networks. Based on the anatomical structures and connections, modality-specific sectors of the TRN and the thalamus appear to be responsible for modality-specific perceptual representation. Furthermore, the coarsely overlapped topographic maps of the TRN appear to be associated with cross-modal or unitary conscious awareness. Throughout the latticework structure of the TRN, conscious perception could be accomplished and elaborated through accumulating intercommunicative processing across the first-order input signal and the higher-order signals from its functionally associated cortices. As the higher-order relay signals run cumulatively through the relevant thalamocortical loops, conscious awareness becomes more refined and sophisticated. [Conclusions] I propose that the thalamocortical integrative communication across first- and higher-order information circuits and repeated feedback looping may account for our conscious awareness. This TRN-modulation hypothesis for conscious awareness provides a comprehensive rationale regarding

  6. Transcranial magnetic stimulation reveals complex cognitive control representations in the rostral frontal cortex.

    Science.gov (United States)

    Bahlmann, J; Beckmann, I; Kuhlemann, I; Schweikard, A; Münte, T F

    2015-08-06

    Convergent evidence suggests that the lateral frontal cortex is at the heart of a brain network subserving cognitive control. Recent theories assume a functional segregation along the rostro-caudal axis of the lateral frontal cortex based on differences in the degree of complexity of cognitive control. However, the functional contribution of specific rostral and caudal sub-regions remains elusive. Here we investigate the impact of disrupting rostral and caudal target regions on cognitive control processes, using Transcranial Magnetic Stimulation (TMS). Participants performed three different task-switching conditions that assessed differences in the degree of complexity of cognitive control processes, after temporally disrupting rostral, or caudal target regions, or a control region. Disrupting the rostral lateral frontal region specifically impaired behavioral performance of the most complex task-switching condition, in comparison to the caudal target region and the control region. These novel findings shed light on the neuroanatomical architecture supporting control over goal-directed behavior.

  7. Trephination of the equine rostral maxillary sinus: efficacy and safety of two trephine sites.

    Science.gov (United States)

    Barakzai, Safia Z; Kane-Smyth, Justine; Lowles, Joanna; Townsend, Neil

    2008-04-01

    To examine 2 rostral maxillary sinus (RMS) trephine sites for safety and efficacy using skulls of horses of varying age. Descriptive study. Cadaveric equine skulls (n=40). Two RMS trephination sites (rostral, caudal) were made in each skull. Radiographic projections using markers at each site were used to determine if sites were within the RMS and directly overlying a cheek tooth. Sinusotomy in 14 skulls was used to determine correlation between radiographic and anatomic location of trephine sites, and of the rostrolateral aspect of the maxillary septum. Age-related risk of trephine site being directly over a cheek tooth was determined using logistic regression. Trephine site was within the RMS in 98% of skulls using the rostral portal and 68% using the caudal portal. The rostral site was over a cheek tooth in 18% of skulls compared with 10% using the caudal site. There was a significant negative relationship between the trephine site overlying a tooth and horse age for rostral (P=.02) and caudal (P=.03) sites. The radiographic appearance of the maxillary septum correlated to the rostrolateral portion of the septum in 12 of 14 skulls that had sinusotomy. The rostral RMS trephine portal is more reliable than the caudal site for entering the RMS. Horses trephine site overlying a cheek tooth and we advise that RMS trephination in this age group be performed with radiographic guidance.

  8. [Complete recovery from transient coma in bilateral paramedian thalamic infarctions].

    Science.gov (United States)

    Casado, J L; Arenas, C; Serrano, V; Moreno Rojas, A; Gil-Néciga, E; Gil-Peralta, A

    1995-01-01

    Bilateral paramedian thalamic infarcts (BPTI) can begin clinically with transient coma, after which symptoms of fluctuating hypersomnolence, irrational behaviour, or amnesic states may be observed. We present two patients with BPTI who began with coma, recovering spontaneously in under eight hours, with no accompanying symptoms.

  9. Hypertensive thalamic hemorrhage. Clinical symptoms and outcomes in 40 cases

    Energy Technology Data Exchange (ETDEWEB)

    Munaka, Masahiro; Nishikawa, Michio; Hirai, Osamu; Kaneko, Takaaki; Watanabe, Syu; Fukuma, Jun; Handa, Hajime

    1988-12-01

    In the past six years, we have had experience with 40 patients with hypertensive thalamic hemorrhages, as verified by CT scan at our hospital within 24 hours. These patients were classified into the following three groups according to the location of the bleeding point and the size of the hematoma: (1) anteromedial (4 cases), (2) posterolateral (16 cases), and (3) massive (20 cases). The (1) and (2) hematomas were small (less than 3 cm in diameter), while those in (3) were large (more than 3 cm in diameter). Twenty cases (50% of all the thalamic hematomas) were small hematomas. The characteristic clinical symptoms of the anteromedial type were a mild disturbance of consciousness and thalamic dementia, while those of the posterolateral type were motor and sensory disturbance, and thalamic aphasia, respectively. Twenty cases (50%) were large hematomas. The clinical symptoms of these cases were mainly consciousness disturbance; 7 of them expired. Based on this experience, it may be considered that the patients whose hematoma size was larger than 3 cm had a poor prognosis and that the patients with the posterolateral type had a poor functional diagnosis.

  10. Impulse sequences of thalamic neurons — An attempted theoretical interpretation

    NARCIS (Netherlands)

    Hoopen, M. ten

    1966-01-01

    1. In the literature interval distributions of thalamic nerve cell activity have been reported, that sometimes showed a preponderance of brief intervals followed by one or more peaks at a longer interval. These results have been compared with those of a model. 2. The model assumes that impulses via

  11. Disrupted thalamic prefrontal pathways in patients with idiopathic dystonia

    NARCIS (Netherlands)

    Bonilha, Leonardo; de Vries, Paulien M.; Hurd, Mark W.; Rorden, Chris; Morgan, Paul S.; Besenski, Nada; Bergmann, Kenneth J.; Hinson, Vanessa K.

    2009-01-01

    There are quantifiable abnormalities in water diffusion properties of the white matter in thalamic and prefrontal areas in patients with idiopathic dystonia (ID). However, it is unclear which pathways are disrupted in these patients. Using probabilistic tractography of high resolution DTI, we recons

  12. Essential Thalamic Contribution to Slow Waves of Natural Sleep

    Science.gov (United States)

    David, François; Schmiedt, Joscha T.; Taylor, Hannah L.; Orban, Gergely; Di Giovanni, Giuseppe; Uebele, Victor N.; Renger, John J.; Lambert, Régis C.; Leresche, Nathalie

    2013-01-01

    Slow waves represent one of the prominent EEG signatures of non-rapid eye movement (non-REM) sleep and are thought to play an important role in the cellular and network plasticity that occurs during this behavioral state. These slow waves of natural sleep are currently considered to be exclusively generated by intrinsic and synaptic mechanisms within neocortical territories, although a role for the thalamus in this key physiological rhythm has been suggested but never demonstrated. Combining neuronal ensemble recordings, microdialysis, and optogenetics, here we show that the block of the thalamic output to the neocortex markedly (up to 50%) decreases the frequency of slow waves recorded during non-REM sleep in freely moving, naturally sleeping-waking rats. A smaller volume of thalamic inactivation than during sleep is required for observing similar effects on EEG slow waves recorded during anesthesia, a condition in which both bursts and single action potentials of thalamocortical neurons are almost exclusively dependent on T-type calcium channels. Thalamic inactivation more strongly reduces spindles than slow waves during both anesthesia and natural sleep. Moreover, selective excitation of thalamocortical neurons strongly entrains EEG slow waves in a narrow frequency band (0.75–1.5 Hz) only when thalamic T-type calcium channels are functionally active. These results demonstrate that the thalamus finely tunes the frequency of slow waves during non-REM sleep and anesthesia, and thus provide the first conclusive evidence that a dynamic interplay of the neocortical and thalamic oscillators of slow waves is required for the full expression of this key physiological EEG rhythm. PMID:24336724

  13. Comparison of sinoscopic techniques for examining the rostral maxillary and ventral conchal sinuses of horses.

    Science.gov (United States)

    Perkins, Justin D; Bennett, Cees; Windley, Zoë; Schumacher, Jim

    2009-07-01

    To develop a reliable technique for sinoscopic examination of the ventral conchal (VCS) and rostral maxillary sinuses (RMS) of horses Descriptive study Cadaveric equine heads (n=40) The VCS and RMS were examined endoscopically using: (1) rostral trephination of the RMS (rostral RMS approach); (2) caudal trephination of the RMS (caudal RMS approach); (3) conchofrontal sinus (CFS) trephination followed by RMS trephination at a site identified by endoscopic transillumination of the maxillary bone at the most rostral aspect of the caudal maxillary sinus (CMS) (light-indicated RMS approach); (4) CFS trephination with fenestration of the ventral conchal bulla (VCB; frontal VCB approach); (5) CMS trephination with VCB fenestration (caudal VCB approach); and (6) CFS and CMS trephination with VCB fenestration (combined VCB approach). Success in observing the rostral and caudal aspects of the VCS and RMS with each approach were: (1) rostral RMS approach (0 horses; 16 horses [40%]); (2) caudal RMS approach (0 horses; 11 horses [28%]); (3) light-indicated RMS approach (3 horses [8%]; 24 horses [60%]); (4) frontal VCB approach (24 horses [60%]; 29 horses [73%] respectively); (5) caudal VCB approach (16 horses [40%] both structures); and (6) combined VCB approach (27 horses [68%]; 35 horses [88%]). Trephination into the CFS coupled with fenestration of the VCB provided consistent access to both the rostral and caudal aspects of the RMS and VCS. A trephine hole into the RMS provided poor access to the VCS, and placed the reserve crowns of the maxillary cheek teeth at risk of damage. The RMS and VCS can be best examined endoscopically using approaches with fenestration of the VCB.

  14. Experimental Cerebral Malaria Spreads along the Rostral Migratory Stream

    Science.gov (United States)

    Hoffmann, Angelika; Pfeil, Johannes; Alfonso, Julieta; Kurz, Felix T.; Sahm, Felix; Heiland, Sabine; Monyer, Hannah; Bendszus, Martin; Mueller, Ann-Kristin; Helluy, Xavier; Pham, Mirko

    2016-01-01

    It is poorly understood how progressive brain swelling in experimental cerebral malaria (ECM) evolves in space and over time, and whether mechanisms of inflammation or microvascular sequestration/obstruction dominate the underlying pathophysiology. We therefore monitored in the Plasmodium berghei ANKA-C57BL/6 murine ECM model, disease manifestation and progression clinically, assessed by the Rapid-Murine-Coma-and-Behavioral-Scale (RMCBS), and by high-resolution in vivo MRI, including sensitive assessment of early blood-brain-barrier-disruption (BBBD), brain edema and microvascular pathology. For histological correlation HE and immunohistochemical staining for microglia and neuroblasts were obtained. Our results demonstrate that BBBD and edema initiated in the olfactory bulb (OB) and spread along the rostral-migratory-stream (RMS) to the subventricular zone of the lateral ventricles, the dorsal-migratory-stream (DMS), and finally to the external capsule (EC) and brainstem (BS). Before clinical symptoms (mean RMCBS = 18.5±1) became evident, a slight, non-significant increase of quantitative T2 and ADC values was observed in OB+RMS. With clinical manifestation (mean RMCBS = 14.2±0.4), T2 and ADC values significantly increased along the OB+RMS (p = 0.049/p = 0.01). Severe ECM (mean RMCBS = 5±2.9) was defined by further spread into more posterior and deeper brain structures until reaching the BS (significant T2 elevation in DMS+EC+BS (p = 0.034)). Quantitative automated histological analyses confirmed microglial activation in areas of BBBD and edema. Activated microglia were closely associated with the RMS and neuroblasts within the RMS were severely misaligned with respect to their physiological linear migration pattern. Microvascular pathology and ischemic brain injury occurred only secondarily, after vasogenic edema formation and were both associated less with clinical severity and the temporal course of ECM. Altogether, we identified a distinct spatiotemporal

  15. Assessing the risk of central post-stroke pain of thalamic origin by lesion mapping.

    Science.gov (United States)

    Sprenger, Till; Seifert, Christian L; Valet, Michael; Andreou, Anna P; Foerschler, Annette; Zimmer, Claus; Collins, D Louis; Goadsby, Peter J; Tölle, Thomas R; Chakravarty, M Mallar

    2012-08-01

    Central post-stroke pain of thalamic origin is an extremely distressing and often refractory disorder. There are no well-established predictors for pain development after thalamic stroke, and the role of different thalamic nuclei is unclear. Here, we used structural magnetic resonance imaging to identify the thalamic nuclei, specifically implicated in the generation of central post-stroke pain of thalamic origin. Lesions of 10 patients with central post-stroke pain of thalamic origin and 10 control patients with thalamic strokes without pain were identified as volumes of interest on magnetic resonance imaging data. Non-linear deformations were estimated to match each image with a high-resolution template and were applied to each volume of interest. By using a digital atlas of the thalamus, we elucidated the involvement of different nuclei with respect to each lesion. Patient and control volumes of interest were summed separately to identify unique areas of involvement. Voxelwise odds ratio maps were calculated to localize the anatomical site where lesions put patients at risk of developing central post-stroke pain of thalamic origin. In the patients with pain, mainly lateral and posterior thalamic nuclei were affected, whereas a more anterior-medial lesion pattern was evident in the controls. The lesions of 9 of 10 pain patients overlapped at the border of the ventral posterior nucleus and the pulvinar, coinciding with the ventrocaudalis portae nucleus. The lesions of this area showed an odds ratio of 81 in favour of developing thalamic pain. The high odds ratio at the ventral posterior nucleus-pulvinar border zone indicates that this area is crucial in the pathogenesis of thalamic pain and demonstrates the feasibility of identifying patients at risk of developing central post-stroke pain of thalamic origin early after thalamic insults. This provides a basis for pre-emptive treatment studies.

  16. Convulsive Movements in Bilateral Paramedian Thalamic and Midbrain Infarction

    Directory of Open Access Journals (Sweden)

    Kazuo Yamashiro

    2011-11-01

    Full Text Available Although some previous reports have described convulsive movements in bilateral paramedian thalamic and midbrain infarction, little is known about their nature. A 71-year-old man presented with impaired consciousness and clonic movements of both arms. Each series of movements lasted 10 to 20 s and occurred at 2- to 3-min intervals, which disappeared after intravenous administration of diazepam and phenytoin. Magnetic resonance imaging showed acute bilateral paramedian thalamic and midbrain infarction. A review of the literature revealed that convulsive movements were observed mostly at the onset of infarction. Clonic movements appeared frequently in the limbs, particularly in both arms. Clinical observations and results of animal experiments suggest that these seizures might originate from the mesencephalic reticular formation. Physicians should recognize this condition, because not only seizure control but also early management of ischemic stroke is required.

  17. Dopamine, fronto-striato-thalamic circuits and risk for psychosis.

    Science.gov (United States)

    Dandash, Orwa; Pantelis, Christos; Fornito, Alex

    2017-02-01

    A series of parallel, integrated circuits link distinct regions of prefrontal cortex with specific nuclei of the striatum and thalamus. Dysfunction of these fronto-striato-thalamic systems is thought to play a major role in the pathogenesis of psychosis. In this review, we examine evidence from human and animal investigations that dysfunction of a specific dorsal fronto-striato-thalamic circuit, linking the dorsolateral prefrontal cortex, dorsal (associative) striatum, and mediodorsal nucleus of the thalamus, is apparent across different stages of psychosis, including prior to the onset of a first episode, suggesting that it represents a candidate risk biomarker. We consider how abnormalities at distinct points in the circuit may give rise to the pattern of findings seen in patient populations, and how these changes relate to disruptions in dopamine, glutamate and GABA signaling. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Clinical observations on treating thalamic hemorrhage into ventricle

    Institute of Scientific and Technical Information of China (English)

    Dong Aiqin; Lv Xiudong; Wang Huagang

    2000-01-01

    Objective To investigate the treatment of severe patients with thalamic hemorrhage into ventricles. Method 12 cases with thalamic hemorrhage into ventricular system were studied, 9 male, 3 femaie, with a mean age of 64 years. All patients were unconscious. The average size of hematoma was 65 ml. Besides general comprehensive care, they received ventricular puncture for ingertion of drainage tape into the cerebral ventricle, infusion with urokinase for clotlysis, lumbar puncture for letting out some cerebrospinal fluid and injection of dexemethasone. Result The patients' clinical symptoms and signs were obviously improved.. The CT scan also demonstrated that hematomas were removed faster. The effective rate was 83.3 per cent, with a murtality of 16.7 per cent. Cohclusion This kind of therapy can increase the clinical cure rate. decrease the disability rate and death rete.

  19. Differential diagnosis of bilateral thalamic lesions; Differenzialdiagnose bilateral Thalamuslaesionen

    Energy Technology Data Exchange (ETDEWEB)

    Linn, J.; Brueckmann, H. [Universitaetsklinikum Muenchen (Germany). Abt. fuer Neuroradiologie; Hoffmann, L.A. [Universitaetsklinikum Muenchen (Germany). Inst. fuer Klinische Neuroimmunologie; Danek, A. [Universitaetsklinikum Muenchen (Germany). Klinik und Poliklinik fuer Neurologie

    2007-03-15

    A multitude of different diseases can result in bilateral thalamic lesions. These include vascular pathologies requiring prompt therapeutic intervention, such as basilar thrombosis or thrombosis of the internal cerebral veins, as well as tumors, infectious or demyelinating diseases, and toxic-metabolic lesions. Therefore, detailed knowledge of the typical radiological findings for the various diseases is essential for determining the correct diagnosis. This review provides a synopsis of the radiological findings for the most important bithalamic lesions and an overview of the literature.

  20. Thalamic volume as a biomarker for disorders of consciousness

    Science.gov (United States)

    Rubeaux, Mathieu; Mahalingam, Jamuna Jayashri; Gomez, Francisco; Nelson, Marvin; Vanhaudenhuyse, Audrey; Bruno, Marie-Aurélie; Gosseries, Olivia; Laureys, Steven; Soddu, Andrea; Lepore, Natasha

    2015-01-01

    Disorders of consciousness (DOC) may be characterized by the degree at which consciousness is impaired, and include for example vegetative state (VS) and minimally conscious state (MCS) patients. Using a reliable marker as a measure of the level of consciousness in such patients is of utmost necessity and importance for their appropriate diagnosis and prognosis. Identification of VS and MCS states based on their behaviors sometimes leads to incorrect inferences due to the influence of a range of factors like motor impairment, fluctuating arousal levels and rapidly habituating responses to name a few.1 The extent of damage in the thalamus, a structure known for its role in arousal regulation, may provide an imaging biomarker to better differentiate between VS and MCS. In this study, we manually segmented the thalamus from T1-weighted brain MRI images in a large cohort of 19 VS and 23 MCS subjects that were examined using the French version of the Coma Recovery Scale Revised (CRS-R).2 This scale is the most trustworthy behavioural diagnosis tool3 for patients with DOC available. The aim was to determine whether a relationship between thalamus volume and consciousness level exists. Results show that total thalamic volume tends to decrease over time after a severe brain injury. Moreover, for subjects in chronic state, the thalamic volume seems to differ with respect to the degree of consciousness that was diagnosed. Finally, for these same chronic patients, the total thalamic volume is varying linearly as a function of the CRS-R score obtained, indicating that thalamic volume may be used as a biomarker to measure the level of consciousness.

  1. How do mammillary body inputs contribute to anterior thalamic function?

    Science.gov (United States)

    Dillingham, Christopher M.; Frizzati, Aura; Nelson, Andrew J.D.; Vann, Seralynne D.

    2015-01-01

    It has long been assumed that the main function of the mammillary bodies is to provide a relay for indirect hippocampal inputs to the anterior thalamic nuclei. Such models afford the mammillary bodies no independent role in memory and overlook the importance of their other, non-hippocampal, inputs. This review focuses on recent advances that herald a new understanding of the importance of the mammillary bodies, and their inputs from the limbic midbrain, for anterior thalamic function. It has become apparent that the mammillary bodies’ contribution to memory is not dependent on afferents from the subicular complex. Rather, the ventral tegmental nucleus of Gudden is a vital source of inputs that support memory processes within the medial mammillary bodies. In parallel, the lateral mammillary bodies, via their connections with the dorsal tegmental nucleus of Gudden, are critical for generating head-direction signals. These two parallel, but distinct, information streams converge on the anterior thalamic nuclei and support different aspects of spatial memory. PMID:25107491

  2. Reproducibility of thalamic segmentation based on probabilistic tractography.

    Science.gov (United States)

    Traynor, Catherine; Heckemann, Rolf A; Hammers, Alexander; O'Muircheartaigh, Jonathan; Crum, William R; Barker, Gareth J; Richardson, Mark P

    2010-08-01

    Reliable identification of thalamic nuclei is required to improve targeting of electrodes used in Deep Brain Stimulation (DBS), and for exploring the role of thalamus in health and disease. A previously described method using probabilistic tractography to segment the thalamus based on connections to cortical target regions was implemented. Both within- and between-subject reproducibility were quantitatively assessed by the overlap of the resulting segmentations; the effect of two different numbers of target regions (6 and 31) on reproducibility of the segmentation results was also investigated. Very high reproducibility was observed when a single dataset was processed multiple times using different starting conditions. Thalamic segmentation was also very reproducible when multiple datasets from the same subject were processed using six cortical target regions. Within-subject reproducibility was reduced when the number of target regions was increased, particularly in medial and posterior regions of the thalamus. A large degree of overlap in segmentation results from different subjects was obtained, particularly in thalamic regions classified as connecting to frontal, parietal, temporal and pre-central cortical target regions.

  3. Adaptive coding of action values in the human rostral cingulate zone

    NARCIS (Netherlands)

    Jocham, G.; Neumann, J.; Klein, T.A.; Danielmeier, C.; Ullsperger, M.

    2009-01-01

    Correctly selecting appropriate actions in an uncertain environment requires gathering experience about the available actions by sampling them over several trials. Recent findings suggest that the human rostral cingulate zone (RCZ) is important for the integration of extended action-outcome associat

  4. Frontal and rostral anterior cingulate (rACC) theta EEG in depression: implications for treatment outcome?

    NARCIS (Netherlands)

    Arns, M.W.; Etkin, A.; Hegerl, U.; Williams, L.M.; DeBattista, C.; Palmer, D.M.; Fitzgerald, P.B.; Harris, A.; deBeuss, R.; Gordon, E.

    2015-01-01

    In major depressive disorder (MDD), elevated theta current density in the rostral anterior cingulate (rACC), as estimated by source localization of scalp-recorded electroencenphalogram (EEG), has been associated with response to antidepressant treatments, whereas elevated frontal theta has been link

  5. Neurotrophic requirements of rat embryonic catecholaminergic neurons from the rostral ventrolateral medulla

    NARCIS (Netherlands)

    Copray, JCVM; Gibbons, H; van Roon, WMC; Comer, AM; Lipski, J

    1999-01-01

    The factors that regulate the ontogeny and differentiation of C1 adrenergic neurons located in the rostral ventrolateral medulla (RVLM) are completely unknown. In the present study, we have investigated the effects of a number of neurotrophic factors on the survival of E18-19 rat C1 adrenergic neuro

  6. Social and Nonsocial Functions of Rostral Prefrontal Cortex: Implications for Education

    Science.gov (United States)

    Gilbert, Sam J.; Burgess, Paul W.

    2008-01-01

    In this article, we discuss the role of rostral prefrontal cortex (approximating Brodmann Area 10) in two domains relevant to education: executive function (particularly prospective memory, our ability to realize delayed intentions) and social cognition (particularly our ability to reflect on our own mental states and the mental states of others).…

  7. Social and Nonsocial Functions of Rostral Prefrontal Cortex: Implications for Education

    Science.gov (United States)

    Gilbert, Sam J.; Burgess, Paul W.

    2008-01-01

    In this article, we discuss the role of rostral prefrontal cortex (approximating Brodmann Area 10) in two domains relevant to education: executive function (particularly prospective memory, our ability to realize delayed intentions) and social cognition (particularly our ability to reflect on our own mental states and the mental states of others).…

  8. Regenerative approach to bilateral rostral mandibular reconstruction in a case series of dogs

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    Boaz eArzi

    2015-03-01

    Full Text Available Extensive rostral mandibulectomy in dogs typically results in instability of the mandibles that may lead to malocclusion, difficulty in eating and drinking, food prehension, and pain of the temporomandibular joint. Large rostral mandibular defects are challenging to reconstruct due to the complex geometry of this region. In order to restore mandibular continuity and stability following extensive rostral mandibulectomy, we developed a surgical technique using a combination of intraoral and extraoral approaches, a locking titanium plate and a compression resistant matrix (CRM infused with rhBMP-2. Furthermore, surgical planning that consisted of computed tomographic (CT scanning and 3D model printing were utilized. We describe a regenerative surgical technique for immediate or delayed reconstruction of critical-size rostral mandibular defects in 5 dogs. Three dogs had healed with intact gingival covering over the mandibular defect and had immediate return to normal function and occlusion. Two dogs had the complication of focal plate exposure and dehiscence, which was corrected with mucosal flaps and suturing; these dogs have since healed with intact gingival covering over the mandibular defect. Mineralized tissue formation was palpated clinically within 2 weeks and solid bone formation within 3 months. Computed tomography findings at 6 months postoperatively demonstrated that the newly regenerated mandibular bone had increased in mineral volume with evidence of integration between the native bone, new bone and CRM compared to the immediate postoperative CT. We conclude that rostral mandibular reconstruction using a regenerative approach provides an excellent solution for restoring mandibular continuity and preventing mandibular instability in dogs.

  9. Altered thalamocortical and intra-thalamic functional connectivity during light sleep compared with wake.

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    Hale, Joanne R; White, Thomas P; Mayhew, Stephen D; Wilson, Rebecca S; Rollings, David T; Khalsa, Sakhvinder; Arvanitis, Theodoros N; Bagshaw, Andrew P

    2016-01-15

    The transition from wakefulness into sleep is accompanied by modified activity in the brain's thalamocortical network. Sleep-related decreases in thalamocortical functional connectivity (FC) have previously been reported, but the extent to which these changes differ between thalamocortical pathways, and patterns of intra-thalamic FC during sleep remain untested. To non-invasively investigate thalamocortical and intra-thalamic FC as a function of sleep stage we recorded simultaneous EEG-fMRI data in 13 healthy participants during their descent into light sleep. Visual scoring of EEG data permitted sleep staging. We derived a functional thalamic parcellation during wakefulness by computing seed-based FC, measured between thalamic voxels and a set of pre-defined cortical regions. Sleep differentially affected FC between these distinct thalamic subdivisions and their associated cortical projections, with significant increases in FC during sleep restricted to sensorimotor connections. In contrast, intra-thalamic FC, both within and between functional thalamic subdivisions, showed significant increases with advancement into sleep. This work demonstrates the complexity and state-specific nature of functional thalamic relationships--both with the cortex and internally--over the sleep/wake cycle, and further highlights the importance of a thalamocortical focus in the study of sleep mechanisms.

  10. Developmental Alterations of Frontal-Striatal-Thalamic Connectivity in Obsessive-Compulsive Disorder

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    Fitzgerald, Kate Dimond; Welsh, Robert C.; Stern, Emily R.; Angstadt, Mike; Hanna, Gregory L.; Abelson, James L.; Taylor, Stephan F.

    2011-01-01

    Objective: Pediatric obsessive-compulsive disorder is characterized by abnormalities of frontal-striatal-thalamic circuitry that appear near illness onset and persist over its course. Distinct frontal-striatal-thalamic loops through cortical centers for cognitive control (anterior cingulate cortex) and emotion processing (ventral medial frontal…

  11. Thalamic activity and biochemical changes in individuals with neuropathic pain following spinal cord injury

    Science.gov (United States)

    Gustin, S.M.; Wrigley, P.J.; Youssef, A.M.; McIndoe, L.; Wilcox, S.L.; Rae, C.D.; Edden, R; Siddall, P.J.; Henderson, L.A.

    2015-01-01

    There is increasing evidence relating thalamic changes to the generation and/or maintenance of neuropathic pain. We have recently reported that neuropathic orofacial pain is associated with altered thalamic anatomy, biochemistry and activity, which may result in disturbed thalamocortical oscillatory circuits. Despite this evidence, it is possible that these thalamic changes are not responsible for the presence of pain per se, but result as a consequence of the injury. To clarify this subject, we compared brain activity and biochemistry in 12 people with below-level neuropathic pain after complete thoracic spinal cord injury to 11 people with similar injuries and no neuropathic pain and 21 age and gender matched healthy controls. Quantitative arterial spinal labelling was used to measure thalamic activity and magnetic resonance spectroscopy was used to determine changes in neuronal variability quantifying N-acetylaspartate and alterations in inhibitory function quantifying gamma amino butyric acid. This study revealed that the presence of neuropathic pain is associated with significant changes in thalamic biochemistry and neuronal activity. More specifically, the presence of neuropathic pain following spinal cord injury is associated with significant reductions in thalamic N-acetylaspartate, gamma amino butyric acid content and blood flow in the region of the thalamic reticular nucleus. Spinal cord injury on its own did not account for these changes. These findings support the hypothesis that neuropathic pain is associated with altered thalamic structure and function, which may disturb central processing and play a key role in the experience of neuropathic pain. PMID:24530612

  12. Developmental Alterations of Frontal-Striatal-Thalamic Connectivity in Obsessive-Compulsive Disorder

    Science.gov (United States)

    Fitzgerald, Kate Dimond; Welsh, Robert C.; Stern, Emily R.; Angstadt, Mike; Hanna, Gregory L.; Abelson, James L.; Taylor, Stephan F.

    2011-01-01

    Objective: Pediatric obsessive-compulsive disorder is characterized by abnormalities of frontal-striatal-thalamic circuitry that appear near illness onset and persist over its course. Distinct frontal-striatal-thalamic loops through cortical centers for cognitive control (anterior cingulate cortex) and emotion processing (ventral medial frontal…

  13. Symmetrical infantile thalamic degeneration with focal cytoplasmic calcification.

    Science.gov (United States)

    Ambler, M; O'Neil, W

    1975-10-27

    Infantile thalamic degeneration is a rare clinico-pathological entity. Restricted location of the lesion and peculiar cytopathological changes serve to distinguish this disorder from other common encephalopathies. Optical and ultrastructural studies demonstrate cytoplasmic calcopherules in previously viable cells. According to current concepts of acute cellular reactions to injury and mechanism of intracellular calcification, the cytological changes cannot be attributed to either hypoxic ischemic cell change or dystrophic calcification. By analogy to other human and pathological material, the most likely basis for nondystrophic calcopherule formation is toxic or infectious injury with local synthesis, or autophagic or phagolysosomal degradation of cellular debris of specific chemical composition favoring calcium deposition.

  14. Alexia without agraphia following biopsy of a left thalamic tumor.

    Science.gov (United States)

    Tamhankar, Madhura A; Coslett, Harry B; Fisher, Michael J; Sutton, Leslie N; Liu, Grant T

    2004-02-01

    Alexia without agraphia is a rare disconnection syndrome characterized by the loss of reading ability with retention of writing and verbal comprehension. We report a patient who developed alexia without agraphia after undergoing a biopsy for a malignant glioma involving the left thalamus. A 15-year-old right-handed male presented with 3 days of severe headache, and vomiting, and 1 month of blurry vision in his right visual field. Magnetic resonance imaging of the brain disclosed a large exophytic mass originating in the left thalamus, with mass effect and hydrocephalus. The patient underwent biopsy of the left thalamic mass via a transcallosal approach. Postoperatively, the patient complained of inability to read or identify letters. Examination revealed alexia without agraphia. The syndrome of alexia without agraphia can be rarely caused after surgery. A transcallosal procedure through the splenium of the corpus callosum may disrupt the visual association fibers traveling from the right occipital cortex to the left angular gyrus. In our case the syndrome occurred because of a preexisting right homonymous hemianopia resulting from a left thalamic tumor.

  15. Thalamic, brainstem, and cerebellar glucose metabolism in the hemiplegic monkey

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    Shimoyama, I.; Dauth, G.W.; Gilman, S.; Frey, K.A.; Penney, J.B. Jr.

    1988-12-01

    Unilateral ablation of cerebral cortical areas 4 and 6 of Brodmann in the macaque monkey results in a contralateral hemiplegia that resolves partially with time. During the phase of dense hemiplegia, local cerebral metabolic rate for glucose (1CMRG1c) is decreased significantly in most of the thalamic nuclei ipsilateral to the ablation, and there are slight contralateral decreases. The lCMRGlc is reduced bilaterally in most of the brainstem nuclei and bilaterally in the deep cerebellar nuclei, but only in the contralateral cerebellar cortex. During the phase of partial motor recovery, lCMRGlc is incompletely restored in many of the thalamic nuclei ipsilateral to the ablation and completely restored in the contralateral nuclei. In the brainstem and deep cerebellar nuclei, poor to moderate recovery occurs bilaterally. Moderate recovery occurs in the contralateral cerebellar cortex. The findings demonstrate that a unilateral cerebral cortical lesion strongly affects lCMRGlc in the thalamus ipsilaterally and in the cerebellar cortex contralaterally, but in the brainstem bilaterally. Partial recovery of lCMRGlc accompanies the progressive motor recovery. The structures affected include those with direct, and also those with indirect, connections to the areas ablated.

  16. Thalamic shape abnormalities in antipsychotic naïve schizophrenia

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    Vijay Danivas

    2013-01-01

    Full Text Available Background: Neurodevelopmental hypothesis of schizophrenia states abnormal pruning as one of the pathogenetic mechanism in schizophrenia. Though thalamic volume abnormalities have been documented, the shape differences of thalamus in antipsychotic-free schizophrenia in comparison with age- and sex-matched healthy volunteers need validation. Materials and Methods: We examined antipsychotic naïve schizophrenia patients ( n=60 and age- and sex-matched healthy volunteers ( n=44. The thalamic shape abnormalities were analyzed from their coded structural magnetic resonance imaging (MRI data using three-dimensional automated image analysis software, FMRIB′s (Oxford Center for the functional MRI of the brain tools-FIRST (FMRIB′s Integrated Registration and Segmentation Tool by creating deformable mesh model. Correlation with the psychopathology scores was carried out using F-statistics. Results: Patients with schizophrenia showed significant inward deformations in the regions corresponding to anterior, ventromedial, mediodorsal, and pulvinar nuclei. There was a direct correlation between negative syndrome score and the deformation in the right mediodorsal and right pulvinar nuclei. Conclusion: The inward deformations of thalamus in antipsychotic naive schizophrenia patients correspond to those nuclei which have reciprocal connections with frontal, superior temporal, and anterior cingulate regions and support the neurodevelopmental hypothesis of schizophrenia.

  17. A case of thalamic hemorrhage-induced diaschisis

    Institute of Scientific and Technical Information of China (English)

    Gang Yao; Yuhong Man; Xijing Mao; Tingmin Yu

    2011-01-01

    Diaschisis refers to a disturbance (inhibition or facilitation) of function in an area remote from the site of a primary brain lesion. Previous studies have confirmed that regional cerebral blood flow and metabolism are noticeably decreased in an infarct region. Transient excessive perfusion appears in the ischemic penumbra, and diaschisis occurs in an area remote from the lesion site, showing decreased regional cerebral blood flow and metabolism. Mirror diaschisis refers to a decrease in oxygen metabolism and blood flow in the "mirror image area" to the infarct regions in the contralateral hemisphere. In this study, a patient with right thalamic hemorrhage was affected with right arm and leg numbness. At 4 months before onset, magnetic resonance imaging of the head demonstrated lacunar infarcts in the left thalamus; therefore the right arm and leg numbness was not associated with lacunar infarcts in the left thalamus. At 8 days following onset, magnetic resonance imaging reexamination did not reveal the focus that could induce right arm and leg numbness and weakness. Thus, it is suggested in this study that the onset of this disease can be explained by mirror diaschisis. That is, right thalamic hemorrhage leads to decreased blood flow and metabolic disturbance in the contralateral thalamus, resulting in right arm and leg numbness.

  18. Early adverse events, HPA activity and rostral anterior cingulate volume in MDD.

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    Michael T Treadway

    Full Text Available BACKGROUND: Prior studies have independently reported associations between major depressive disorder (MDD, elevated cortisol concentrations, early adverse events and region-specific decreases in grey matter volume, but the relationships among these variables are unclear. In the present study, we sought to evaluate the relationships between grey matter volume, early adverse events and cortisol levels in MDD. METHODS/RESULTS: Grey matter volume was compared between 19 controls and 19 individuals with MDD using voxel-based morphometry. A history of early adverse events was assessed using the Childhood Trauma Questionnaire. Subjects also provided salivary cortisol samples. Depressed patients showed decreased grey matter volume in the rostral ACC as compared to controls. Rostral ACC volume was inversely correlated with both cortisol and early adverse events. CONCLUSIONS: These findings suggest a key relationship between ACC morphology, a history of early adverse events and circulating cortisol in the pathophysiology of MDD.

  19. Developmental synergy between thalamic structure and interhemispheric connectivity in the visual system of preterm infants

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    Rafael Ceschin

    2015-01-01

    Full Text Available Thalamic structural co-variation with cortical regions has been demonstrated in preterm infants, but its relationship to cortical function and severity of non-cystic white matter injury (non-cystic WMI is unclear. The relationship between thalamic morphology and both cortical network synchronization and cortical structural connectivity has not been established. We tested the hypothesis that in preterm neonates, thalamic volume would correlate with primary cortical visual function and microstructural integrity of cortico-cortical visual association pathways. A total of 80 term-equivalent preterm and 44 term-born infants underwent high-resolution structural imaging coupled with visual functional magnetic resonance imaging or diffusion tensor imaging. There was a strong correlation between thalamic volume and primary visual cortical activation in preterms with non-cystic WMI (r = 0.81, p-value = 0.001. Thalamic volume also correlated strongly with interhemispheric cortico-cortical connectivity (splenium in preterm neonates with a relatively higher severity of non-cystic WMI (p-value < 0.001. In contrast, there was lower correlation between thalamic volume and intrahemispheric cortico-cortical connectivity, including the inferior longitudinal fasciculus and inferior frontal orbital fasciculus. This study shows distinct temporal overlap in the disruption of thalamo-cortical and interhemispheric cortico-cortical connectivity in preterm infants suggesting developmental synergy between thalamic morphology and the emergence of cortical networks in the last trimester.

  20. An Analysis of the Characteristics of Aphasia Caused by The Thalamic Stroke

    Institute of Scientific and Technical Information of China (English)

    Lu Chongxia

    2000-01-01

    The aphasia of 21 patients with thalamic stroke was din ically classified and analysed with the method of standard Chinese aphasic test, and the possible relationship between the thalamic damage and aphasia was discussed. The results showed that the notable characteris tics of the aphasia caused by thalamic stroke was subcortical aphasia and the language dominance of thalamus mainly located at the left side, but the right side of thalamus was also involved with language. The data in dicated that the thalamus is a constituent part in nervous network of lan guage.

  1. Effects of donepezil on behavioural manifestations of thalamic infarction: a single case observation

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    Rodrigo eRiveros

    2011-03-01

    Full Text Available Objective: To examine the effect of donepezil for the treatment of cognitive and behavioural disorders associated with thalamic lesions in a 45 years old male who suffered an infarct in the left thalamus. Background: Recent studies suggest that donepezil may improve executive functions impairments due to subcortical ischemic lesionsMethod: The crossover effects of donepezil were analyzed in a single case of thalamic infarction with cognitive and behavioural alterations. Results: Significant behavioural modifications related to improved performances in executive functions were observed with the treatment. Conclusions: The results suggest that donepezil may have significant effect on executive functions that can alter behavioural outcomes after thalamic infarctions

  2. Positive Apraclonidine Test in Horner Syndrome Caused by Thalamic Hemorrhage.

    Science.gov (United States)

    Kauh, Courtney Y; Bursztyn, Lulu L C D

    2015-09-01

    Reversal of anisocoria following instillation of apraclonidine 0.5% has been reported in Horner syndrome caused by lesions of the central and peripheral nervous system. The shortest documented latency between symptom onset and a positive apraclonidine test is 36 hours, occurring in a patient with a pontomedullary infarct. We present the case of a 69-year-old man with Horner syndrome due to thalamic hemorrhage in whom apraclonidine testing demonstrated reversal of anisocoria 4 days after symptom onset. This is the first reported case of a positive apraclonidine test in a Horner syndrome caused by a lesion at this site. It suggests that apraclonidine testing is useful in confirming the diagnosis within days of onset even in a lesion located at the most proximal portion of the oculosympathetic pathway.

  3. Hemiballismus That Develops upon Thalamic Hemorrhage: A Case Report

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    Aybala Neslihan Alagöz

    2016-04-01

    Full Text Available Hemichorea is characterized by sudden, spasmodic, irregular, short-term finger, hand, arm, face, tongue or head movements including one half of body. Ballismus concept defines the high-amplitude, violent, centrifugal or throwing motions. Hemichorea-hemiballismus are the most frequently reported movement disorders in patients with acute stroke. Even if it is believed to occur depending on the effect on contralateral subthalamic nucleus; it has been reported that in the following years there have been choreic and ballistic movements in various lesions intersecting the afferent and efferent subtalamopalidal paths of basal ganglion. In this article; hemiballismus, which has developed after thalamic hemorrhage, of an 63 year old female patient is presented.

  4. Transmissibility studies of vacuolar changes in the rostral colliculus of pigs

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    Spencer Yvonne I

    2009-09-01

    Full Text Available Abstract Background Histopathological examinations of brains from healthy pigs have revealed localised vacuolar changes, predominantly in the rostral colliculus, that are similar to the neuropil vacuolation featured in the transmissible spongiform encephalopathies and have been described in pigs challenged parenterally with the agent causing bovine spongiform encephalopathy (BSE. Feedstuff containing BSE-contaminated meat and bone meal (MBM may have been fed to pigs prior to the ban of mammalian MBM in feed of farmed livestock in the United Kingdom in 1996, but there is no evidence of the natural occurrence of a transmissible spongiform encephalopathy (TSE in the domestic pig. Furthermore, experimental transmission of BSE to pigs by the oral route has been unsuccessful. A study was conducted to investigate whether the localised vacuolar changes in the porcine brain were associated with a transmissible aetiology and therefore biologically significant. Two groups of ten pigs were inoculated parenterally with vacuolated rostral colliculus from healthy pigs either born before 1996 or born after 1996. Controls included ten pigs similarly inoculated with rostral colliculus from New Zealand-derived pigs and nine pigs inoculated with a bovine BSE brain homogenate. Results None of the pigs inoculated with rostral colliculus developed a TSE-like neurological disease up to five years post inoculation when the study was terminated, and disease-associated prion protein, PrPd, was not detected in the brains of these pigs. By contrast, eight of nine BSE-inoculated pigs developed neurological signs, two of which had detectable PrPd by postmortem tests. No significant histopathological changes were detected to account for the clinical signs in the PrPd-negative, BSE-inoculated pigs. Conclusion The findings in this study suggest that vacuolation in the porcine rostral colliculus is not caused by a transmissible agent and is probably a clinically insignificant

  5. Thalamic Volume Is Reduced in Cervical and Laryngeal Dystonias

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    Waugh, Jeff L.; Kuster, John K.; Levenstein, Jacob M.; Makris, Nikos; Multhaupt-Buell, Trisha J.; Sudarsky, Lewis R.; Breiter, Hans C.; Sharma, Nutan; Blood, Anne J.

    2016-01-01

    Background Dystonia, a debilitating movement disorder characterized by abnormal fixed positions and/or twisting postures, is associated with dysfunction of motor control networks. While gross brain lesions can produce secondary dystonias, advanced neuroimaging techniques have been required to identify network abnormalities in primary dystonias. Prior neuroimaging studies have provided valuable insights into the pathophysiology of dystonia, but few directly assessed the gross volume of motor control regions, and to our knowledge, none identified abnormalities common to multiple types of idiopathic focal dystonia. Methods We used two gross volumetric segmentation techniques and one voxelwise volumetric technique (voxel based morphometry, VBM) to compare regional volume between matched healthy controls and patients with idiopathic primary focal dystonia (cervical, n = 17, laryngeal, n = 7). We used (1) automated gross volume measures of eight motor control regions using the FreeSurfer analysis package; (2) blinded, anatomist-supervised manual segmentation of the whole thalamus (also gross volume); and (3) voxel based morphometry, which measures local T1-weighted signal intensity and estimates gray matter density or volume at the level of single voxels, for both whole-brain and thalamus. Results Using both automated and manual gross volumetry, we found a significant volume decrease only in the thalamus in two focal dystonias. Decreases in whole-thalamic volume were independent of head and brain size, laterality of symptoms, and duration. VBM measures did not differ between dystonia and control groups in any motor control region. Conclusions Reduced thalamic gross volume, detected in two independent analyses, suggests a common anatomical abnormality in cervical dystonia and spasmodic dysphonia. Defining the structural underpinnings of dystonia may require such complementary approaches. PMID:27171035

  6. Thalamic Volume Is Reduced in Cervical and Laryngeal Dystonias.

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    Jeff L Waugh

    Full Text Available Dystonia, a debilitating movement disorder characterized by abnormal fixed positions and/or twisting postures, is associated with dysfunction of motor control networks. While gross brain lesions can produce secondary dystonias, advanced neuroimaging techniques have been required to identify network abnormalities in primary dystonias. Prior neuroimaging studies have provided valuable insights into the pathophysiology of dystonia, but few directly assessed the gross volume of motor control regions, and to our knowledge, none identified abnormalities common to multiple types of idiopathic focal dystonia.We used two gross volumetric segmentation techniques and one voxelwise volumetric technique (voxel based morphometry, VBM to compare regional volume between matched healthy controls and patients with idiopathic primary focal dystonia (cervical, n = 17, laryngeal, n = 7. We used (1 automated gross volume measures of eight motor control regions using the FreeSurfer analysis package; (2 blinded, anatomist-supervised manual segmentation of the whole thalamus (also gross volume; and (3 voxel based morphometry, which measures local T1-weighted signal intensity and estimates gray matter density or volume at the level of single voxels, for both whole-brain and thalamus.Using both automated and manual gross volumetry, we found a significant volume decrease only in the thalamus in two focal dystonias. Decreases in whole-thalamic volume were independent of head and brain size, laterality of symptoms, and duration. VBM measures did not differ between dystonia and control groups in any motor control region.Reduced thalamic gross volume, detected in two independent analyses, suggests a common anatomical abnormality in cervical dystonia and spasmodic dysphonia. Defining the structural underpinnings of dystonia may require such complementary approaches.

  7. Prenatal thalamic waves regulate cortical area size prior to sensory processing

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    Moreno-Juan, Verónica; Filipchuk, Anton; Antón-Bolaños, Noelia; Mezzera, Cecilia; Gezelius, Henrik; Andrés, Belen; Rodríguez-Malmierca, Luis; Susín, Rafael; Schaad, Olivier; Iwasato, Takuji; Schüle, Roland; Rutlin, Michael; Nelson, Sacha; Ducret, Sebastien; Valdeolmillos, Miguel; Rijli, Filippo M.; López-Bendito, Guillermina

    2017-01-01

    The cerebral cortex is organized into specialized sensory areas, whose initial territory is determined by intracortical molecular determinants. Yet, sensory cortical area size appears to be fine tuned during development to respond to functional adaptations. Here we demonstrate the existence of a prenatal sub-cortical mechanism that regulates the cortical areas size in mice. This mechanism is mediated by spontaneous thalamic calcium waves that propagate among sensory-modality thalamic nuclei up to the cortex and that provide a means of communication among sensory systems. Wave pattern alterations in one nucleus lead to changes in the pattern of the remaining ones, triggering changes in thalamic gene expression and cortical area size. Thus, silencing calcium waves in the auditory thalamus induces Rorβ upregulation in a neighbouring somatosensory nucleus preluding the enlargement of the barrel-field. These findings reveal that embryonic thalamic calcium waves coordinate cortical sensory area patterning and plasticity prior to sensory information processing. PMID:28155854

  8. Thalamus parcellation using multi-modal feature classification and thalamic nuclei priors

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    Glaister, Jeffrey; Carass, Aaron; Stough, Joshua V.; Calabresi, Peter A.; Prince, Jerry L.

    2016-03-01

    Segmentation of the thalamus and thalamic nuclei is useful to quantify volumetric changes from neurodegenerative diseases. Most thalamus segmentation algorithms only use T1-weighted magnetic resonance images and current thalamic parcellation methods require manual interaction. Smaller nuclei, such as the lateral and medial geniculates, are challenging to locate due to their small size. We propose an automated segmentation algorithm using a set of features derived from diffusion tensor image (DTI) and thalamic nuclei location priors. After extracting features, a hierarchical random forest classifier is trained to locate the thalamus. A second random forest classifies thalamus voxels as belonging to one of six thalamic nuclei classes. The proposed algorithm was tested using a leave-one-out cross validation scheme and compared with state-of-the-art algorithms. The proposed algorithm has a higher Dice score compared to other methods for the whole thalamus and several nuclei.

  9. Multiple clusters of release sites formed by individual thalamic afferents onto cortical interneurons ensure reliable transmission.

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    Bagnall, Martha W; Hull, Court; Bushong, Eric A; Ellisman, Mark H; Scanziani, Massimo

    2011-07-14

    Thalamic afferents supply the cortex with sensory information by contacting both excitatory neurons and inhibitory interneurons. Interestingly, thalamic contacts with interneurons constitute such a powerful synapse that even one afferent can fire interneurons, thereby driving feedforward inhibition. However, the spatial representation of this potent synapse on interneuron dendrites is poorly understood. Using Ca imaging and electron microscopy we show that an individual thalamic afferent forms multiple contacts with the interneuronal proximal dendritic arbor, preferentially near branch points. More contacts are correlated with larger amplitude synaptic responses. Each contact, consisting of a single bouton, can release up to seven vesicles simultaneously, resulting in graded and reliable Ca transients. Computational modeling indicates that the release of multiple vesicles at each contact minimally reduces the efficiency of the thalamic afferent in exciting the interneuron. This strategy preserves the spatial representation of thalamocortical inputs across the dendritic arbor over a wide range of release conditions.

  10. Fast cortical oscillation after thalamic degeneration: pivotal role of NMDA receptor.

    Science.gov (United States)

    Kyuhou, Shin-ichi; Gemba, Hisae

    2007-04-27

    We examined electrophysiological and molecular changes of the thalamocortical system after thalamic degeneration in Purkinje cell degeneration (pcd) mice. In pcd mice, neurons in specific thalamic nuclei including the ventral medial geniculate nucleus began to degenerate around postnatal day 50, whereas the visual thalamic nucleus and nonspecific thalamic nuclei remained almost intact. In association with the morphological changes, auditory evoked potentials in the primary auditory cortex (AC) began to decrease gradually. Fast Fourier transform analysis of spontaneous cortical field potentials revealed that fast oscillation (FO) around 25 Hz occurred in the AC but not in the visual cortex. Quantitative mRNA analysis demonstrated that expression of the N-methyl-D-aspartate (NMDA) receptor was up-regulated in the AC but not in the visual cortex. Systemic administration of an NMDA antagonist abolished the FO in the AC. These results indicate that increased NMDA activity may cause the FO in the AC of pcd mice.

  11. Endoscopic considerations treating hydrocephalus caused by basal ganglia and large thalamic tumors

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    Jonathan Roth

    2015-01-01

    Conclusions: Endoscopic surgery may potentially play a significant role in the initial management of patients with large basal ganglia and large thalamic tumors causing obstructive hydrocephalus. Technical nuances and individualized goals are crucial for optimal outcomes.

  12. Usefulness of gamma knife pituitary surgery to control thalamic pain after treatment of thalamic malignant lymphoma and report of pathology of gamma knife lesions

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    Utsuki Satoshi

    2009-01-01

    Full Text Available Here, we describe the first reported autopsy findings following gamma knife surgery for thalamic pain. A 62-year-old man presented with thalamic pain after treatment for thalamic malignant lymphoma. He was treated with narcotic drugs, but his pain was uncontrollable. Treatment using gamma knife surgery on the pituitary gland using a maximum dose of 180 Gy, led to the control of his intractable pain with lower doses of drugs. His death was pain-free and was caused by a recurrence of the tumor, six months after gamma knife surgery. An autopsy was performed and necrosis was present in the area of the pituitary gland where it borders the pituitary stalk. Half of the adenohypophysis was not necrotic, and necrosis was not found in the pituitary stalk.

  13. Aphasia or neglect after thalamic stroke: the various ways they may be related to cortical hypoperfusion

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    Rajani eSebastian

    2014-11-01

    Full Text Available Although aphasia and hemispatial neglect are classically labeled as cortical deficits, language deficits or hemispatial neglect following lesions to subcortical regions have been reported in many studies. However, whether or not aphasia and hemispatial neglect can be caused by subcortical lesions alone has been a matter of controversy. It has been previously shown that most cases of aphasia or hemispatial neglect due to acute non-thalamic subcortical infarcts can be accounted for by concurrent cortical hypoperfusion due to arterial stenosis or occlusion, reversible by restoring blood flow to the cortex. In this study we evaluated whether aphasia or neglect occur after acute thalamic infarct without cortical hypoperfusion due to arterial stenosis or occlusion. Twenty patients with isolated acute thalamic infarcts (10 right and 10 left underwent MRI scanning and detailed cognitive testing. Results revealed that 5/10 patients with left thalamic infarcts had aphasia and only 1 had cortical hypoperfusion, whereas 2/10 patients with right thalamic infarcts had hemispatial neglect and both had cortical hypoperfusion. These findings indicate that aphasia was observed in some cases of isolated left thalamic infarcts without cortical hypoerfusion due to arterial stenosis or occlusion (measured with time to peak delays, but neglect occurred after isolated right thalamic infarcts only when there was cortical hypoperfusion due to arterial stenosis or occlusion. Therefore, neglect after acute right thalamic infarct should trigger evaluation for cortical hypoperfusion that might improve with restoration of blood flow. Further investigation in a larger group of patients and with other imaging modalities is warranted to confirm these findings.

  14. Aphasia or Neglect after Thalamic Stroke: The Various Ways They may be Related to Cortical Hypoperfusion.

    Science.gov (United States)

    Sebastian, Rajani; Schein, Mara G; Davis, Cameron; Gomez, Yessenia; Newhart, Melissa; Oishi, Kenichi; Hillis, Argye E

    2014-01-01

    Although aphasia and hemispatial neglect are classically labeled as cortical deficits, language deficits or hemispatial neglect following lesions to subcortical regions have been reported in many studies. However, whether or not aphasia and hemispatial neglect can be caused by subcortical lesions alone has been a matter of controversy. It has been previously shown that most cases of aphasia or hemispatial neglect due to acute non-thalamic subcortical infarcts can be accounted for by concurrent cortical hypoperfusion due to arterial stenosis or occlusion, reversible by restoring blood flow to the cortex. In this study, we evaluated whether aphasia or neglect occur after acute thalamic infarct without cortical hypoperfusion due to arterial stenosis or occlusion. Twenty patients with isolated acute thalamic infarcts (10 right and 10 left) underwent MRI scanning and detailed cognitive testing. Results revealed that 5/10 patients with left thalamic infarcts had aphasia and only 1 had cortical hypoperfusion, whereas 2/10 patients with right thalamic infarcts had hemispatial neglect and both had cortical hypoperfusion. These findings indicate that aphasia was observed in some cases of isolated left thalamic infarcts without cortical hypoerfusion due to arterial stenosis or occlusion (measured with time-to-peak delays), but neglect occurred after isolated right thalamic infarcts only when there was cortical hypoperfusion due to arterial stenosis or occlusion. Therefore, neglect after acute right thalamic infarct should trigger evaluation for cortical hypoperfusion that might improve with restoration of blood flow. Further investigation in a larger group of patients and with other imaging modalities is warranted to confirm these findings.

  15. Thalamic activity and biochemical changes in individuals with neuropathic pain after spinal cord injury.

    Science.gov (United States)

    Gustin, S M; Wrigley, P J; Youssef, A M; McIndoe, L; Wilcox, S L; Rae, C D; Edden, R A E; Siddall, P J; Henderson, L A

    2014-05-01

    There is increasing evidence relating thalamic changes to the generation and/or maintenance of neuropathic pain. We have recently reported that neuropathic orofacial pain is associated with altered thalamic anatomy, biochemistry, and activity, which may result in disturbed thalamocortical oscillatory circuits. Despite this evidence, it is possible that these thalamic changes are not responsible for the presence of pain per se, but result as a consequence of the injury. To clarify this subject, we compared brain activity and biochemistry in 12 people with below-level neuropathic pain after complete thoracic spinal cord injury with 11 people with similar injuries and no neuropathic pain and 21 age- and gender-matched healthy control subjects. Quantitative arterial spinal labelling was used to measure thalamic activity, and magnetic resonance spectroscopy was used to determine changes in neuronal variability quantifying N-acetylaspartate and alterations in inhibitory function quantifying gamma amino butyric acid. This study revealed that the presence of neuropathic pain is associated with significant changes in thalamic biochemistry and neuronal activity. More specifically, the presence of neuropathic pain after spinal cord injury is associated with significant reductions in thalamic N-acetylaspartate, gamma amino butyric acid content, and blood flow in the region of the thalamic reticular nucleus. Spinal cord injury on its own did not account for these changes. These findings support the hypothesis that neuropathic pain is associated with altered thalamic structure and function, which may disturb central processing and play a key role in the experience of neuropathic pain. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  16. Why do lesions in the rodent anterior thalamic nuclei cause such severe spatial deficits?

    Science.gov (United States)

    Aggleton, John P.; Nelson, Andrew J.D.

    2015-01-01

    Lesions of the rodent anterior thalamic nuclei cause severe deficits to multiple spatial learning tasks. Possible explanations for these effects are examined, with particular reference to T-maze alternation. Anterior thalamic lesions not only impair allocentric place learning but also disrupt other spatial processes, including direction learning, path integration, and relative length discriminations, as well as aspects of nonspatial learning, e.g., temporal discriminations. Working memory tasks, such as T-maze alternation, appear particularly sensitive as they combine an array of these spatial and nonspatial demands. This sensitivity partly reflects the different functions supported by individual anterior thalamic nuclei, though it is argued that anterior thalamic lesion effects also arise from covert pathology in sites distal to the thalamus, most critically in the retrosplenial cortex and hippocampus. This two-level account, involving both local and distal lesion effects, explains the range and severity of the spatial deficits following anterior thalamic lesions. These findings highlight how the anterior thalamic nuclei form a key component in a series of interdependent systems that support multiple spatial functions. PMID:25195980

  17. Changes in Activity of the Same Thalamic Neurons to Repeated Nociception in Behaving Mice.

    Science.gov (United States)

    Huh, Yeowool; Cho, Jeiwon

    2015-01-01

    The sensory thalamus has been reported to play a key role in central pain sensory modulation and processing, but its response to repeated nociception at thalamic level is not well known. Current study investigated thalamic response to repeated nociception by recording and comparing the activity of the same thalamic neuron during the 1st and 2nd formalin injection induced nociception, with a week interval between injections, in awake and behaving mice. Behaviorally, the 2nd injection induced greater nociceptive responses than the 1st. Thalamic activity mirrored these behavioral changes with greater firing rate during the 2nd injection. Analysis of tonic and burst firing, characteristic firing pattern of thalamic neurons, revealed that tonic firing activity was potentiated while burst firing activity was not significantly changed by the 2nd injection relative to the 1st. Likewise, burst firing property changes, which has been consistently associated with different phases of nociception, were not induced by the 2nd injection. Overall, data suggest that repeated nociception potentiated responsiveness of thalamic neurons and confirmed that tonic firing transmits nociceptive signals.

  18. Selective importance of the rat anterior thalamic nuclei for configural learning involving distal spatial cues.

    Science.gov (United States)

    Dumont, Julie R; Amin, Eman; Aggleton, John P

    2014-01-01

    To test potential parallels between hippocampal and anterior thalamic function, rats with anterior thalamic lesions were trained on a series of biconditional learning tasks. The anterior thalamic lesions did not disrupt learning two biconditional associations in operant chambers where a specific auditory stimulus (tone or click) had a differential outcome depending on whether it was paired with a particular visual context (spot or checkered wall-paper) or a particular thermal context (warm or cool). Likewise, rats with anterior thalamic lesions successfully learnt a biconditional task when they were reinforced for digging in one of two distinct cups (containing either beads or shredded paper), depending on the particular appearance of the local context on which the cup was placed (one of two textured floors). In contrast, the same rats were severely impaired at learning the biconditional rule to select a specific cup when in a particular location within the test room. Place learning was then tested with a series of go/no-go discriminations. Rats with anterior thalamic nuclei lesions could learn to discriminate between two locations when they were approached from a constant direction. They could not, however, use this acquired location information to solve a subsequent spatial biconditional task where those same places dictated the correct choice of digging cup. Anterior thalamic lesions produced a selective, but severe, biconditional learning deficit when the task incorporated distal spatial cues. This deficit mirrors that seen in rats with hippocampal lesions, so extending potential interdependencies between the two sites.

  19. Posterior hypothalamic receptors involved in the cardiovascular changes elicited by electrical stimulation of the rostral ventrolateral medulla.

    Science.gov (United States)

    Bachelard, H; Rivest, R; Marsden, C A

    1991-07-01

    The posterior hypothalamic receptors involved in the cardiovascular responses to electrical stimulation of the rostral ventrolateral medulla were investigated in urethane-anaesthetized rats. Electrical stimulation of the rostral ventrolateral medulla produced a significant increase in systolic blood pressure. This response was significantly attenuated by the prior administration of d,l-propranolol (20 micrograms), clonidine (8 micrograms), atropine (8 micrograms) or methysergide (10 micrograms) into the posterior hypothalamus, but not by cimetidine (11 micrograms), chlorpheniramine (12 micrograms), naloxone (10 micrograms) or a vasopressin V1 antagonist (100 ng). The effect of clonidine (8 micrograms) on the pressor response to stimulation of the rostral ventrolateral medulla was antagonized by idazoxan (66 micrograms). These results confirm that the cardiovascular changes elicited by stimulation of the rostral ventrolateral medulla area are, in part, centrally modulated by alpha 2 and beta-adrenoceptors in the posterior hypothalamus which exert respectively, inhibitory and stimulatory effect. Furthermore the results indicate the involvement of posterior hypothalamic cholinergic and serotonergic receptors in the pressor response produced by stimulation of the rostral ventrolateral medulla.

  20. Prognostic factors influencing the outcome of thalamic glioma.

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    Pathy S

    2002-01-01

    Full Text Available Retrospective analysis of 27 patients of thalamic glioma including adults and children treated over a period of 7 years from 1991-1997 was done. The study group included 19 males and 8 females; 9 patients were less than 15 years and 18 patients more than 15 years of age at the time of diagnosis. The commonest symptoms were headache and vomiting. 12 patients underwent VP shunt as an initial procedure and 7 underwent total or partial surgical resection. Confirmed histopathological examination was possible in 16 patients; while 12 had low grade astrocytoma, 4 cases had high grade histology. All patients were treated with radiotherapy to a total dose of 50-60 Gy in 25-30 fractions. Median follow up was 9.63 months. The disease free survival in these patients was 28% at 2 years. Prognostic factors which included age, sex, duration of symptoms, surgical procedures, histology and radiotherapy dose were evaluated for significance. A subtotal resection conferred a better prognosis.

  1. Thalamic and parietal brain morphology predicts auditory category learning.

    Science.gov (United States)

    Scharinger, Mathias; Henry, Molly J; Erb, Julia; Meyer, Lars; Obleser, Jonas

    2014-01-01

    Auditory categorization is a vital skill involving the attribution of meaning to acoustic events, engaging domain-specific (i.e., auditory) as well as domain-general (e.g., executive) brain networks. A listener's ability to categorize novel acoustic stimuli should therefore depend on both, with the domain-general network being particularly relevant for adaptively changing listening strategies and directing attention to relevant acoustic cues. Here we assessed adaptive listening behavior, using complex acoustic stimuli with an initially salient (but later degraded) spectral cue and a secondary, duration cue that remained nondegraded. We employed voxel-based morphometry (VBM) to identify cortical and subcortical brain structures whose individual neuroanatomy predicted task performance and the ability to optimally switch to making use of temporal cues after spectral degradation. Behavioral listening strategies were assessed by logistic regression and revealed mainly strategy switches in the expected direction, with considerable individual differences. Gray-matter probability in the left inferior parietal lobule (BA 40) and left precentral gyrus was predictive of "optimal" strategy switch, while gray-matter probability in thalamic areas, comprising the medial geniculate body, co-varied with overall performance. Taken together, our findings suggest that successful auditory categorization relies on domain-specific neural circuits in the ascending auditory pathway, while adaptive listening behavior depends more on brain structure in parietal cortex, enabling the (re)direction of attention to salient stimulus properties.

  2. Reduced thalamic and pontine connectivity in Kleine-Levin syndrome

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    Maria eEngström

    2014-04-01

    Full Text Available The Kleine-Levin syndrome is a rare sleep disorder, characterized by exceptionally long sleep episodes. The neuropathology of the syndrome is unknown and treatment is often inadequate. The aim of the study was to improve understanding of the underlying neuropathology, related to cerebral networks, in Kleine-Levin syndrome during sleep episodes. One patient with Kleine-Levin syndrome and congenital nystagmus, was investigated by resting state functional Magnetic Resonance Imaging during both asymptomatic and hypersomnic periods. Fourteen healthy subjects were also investigated as control samples. Functional connectivity was assessed from seed regions of interest in the thalamus and the dorsal pons. Thalamic connectivity was normal in the asymptomatic patient whereas the connectivity between the brain stem, including dorsal pons, and the thalamus was diminished during hypersomnia. These results suggest that the patient’s nystagmus and hypersomnia might have their pathological origin in adjacent dorsal pontine regions. This finding provides additional knowledge of the cerebral networks involved in the neuropathology of this disabling disorder. Furthermore, these findings regarding a rare syndrome have broad implications and results could be of interest to researchers and clinicians in the whole field of sleep medicine.

  3. Centromedian thalamic nuclei deep brain stimulation in refractory status epilepticus.

    Science.gov (United States)

    Valentín, Antonio; Nguyen, Huy Q; Skupenova, Alena M; Agirre-Arrizubieta, Zaloa; Jewell, Sharon; Mullatti, Nandini; Moran, Nicholas F; Richardson, Mark P; Selway, Richard P; Alarcón, Gonzalo

    2012-10-01

    Refractory status epilepticus (RSE) is associated with high mortality. We report a potential treatment alternative. Deep brain stimulation (DBS) of the centromedian thalamic nuclei (CMN) can be effective in the treatment of RSE. Report of the evolution of RSE after DBS of the CMN in a 27-year-old man. In the course of an encephalopathy of unknown origin, and after a cardiac arrest, the patient developed RSE with myoclonic jerks and generalized tonic-clonic seizures. The EEG showed continuous generalized periodic epileptiform discharges (GPEDS). Five weeks after RSE onset, bilateral DBS of the CMN was started. This treatment was immediately followed by disappearance of tonic-clonic seizures and GPEDS, suggesting a resolution of RSE. The patient continued having multifocal myoclonic jerks, probably subcortical in origin, which resolved after 4 weeks. The patient remained clinically stable for 2 months in a persistent vegetative state. The remission of RSE, the abolition of GPEDS, and the patient survival suggest that DBS of the CMN may be efficacious in the treatment of refractory, generalized status epilepticus. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Efficacy of clonidine in patients with essential hypertension with neurovascular contact of the rostral ventrolateral medulla.

    Science.gov (United States)

    Sakuma, Takao; Morimoto, Satoshi; Aota, Yasuko; Takahashi, Nobuyuki; Toyoda, Nagaoki; Kosaki, Atsushi; Maehara, Minoru; Tanigawa, Noboru; Ikeda, Koshi; Sawada, Satoshi; Iwasaka, Toshiji

    2010-06-01

    The rostral ventrolateral medulla (RVLM) is an important center for regulation of sympathetic nerve activity. Several clinical studies have suggested an association between neurovascular contact (NVC) of RVLM and essential hypertension. Microvascular decompression (MVD) of RVLM decreases blood pressure (BP) in hypertensive patients with NVC of this region. Therefore, MVD could be a useful therapeutic strategy to reduce BP in these patients. However, as MVD is an invasive procedure, it is worthy to seek useful antihypertensive agents for hypertensive patients with NVC. It is reported that sympathetic nerve activity is elevated in patients with hypertension accompanied by NVC of RVLM. It is anticipated that sympatholytic agents could be effective in lowering BP in these patients. In this study, we investigated the efficacy of clonidine, an alpha2 adrenergic agonist, in essential hypertensives with NVC of RVLM. Thirty consecutive essential hypertensive patients with NVC and 30 consecutive essential hypertensive patients without contact were treated with clonidine for 4 weeks, and decreases in BP and plasma norepinephrine levels were compared between the two groups. Decreases in BP and plasma norepinephrine levels were significantly greater in patients with NVC than in those without contact. These results suggest that clonidine exhibits significantly greater reductions of BP and sympathetic nerve activity in essential hypertensive patients with NVC compared with those without contact of the rostral ventrolateral medulla.

  5. Rostral and caudal prefrontal contribution to creativity: A meta-analysis of functional imaging data

    Directory of Open Access Journals (Sweden)

    Gil eGonen-Yaacovi

    2013-08-01

    Full Text Available Creativity is of central importance for human civilization, yet its neurocognitive bases are poorly understood. The aim of the present study was to integrate existing functional imaging data by using the meta-analysis approach. We reviewed 34 functional imaging studies that reported activation foci during tasks assumed to engage creative thinking in healthy adults. A coordinate-based meta-analysis using Activation Likelihood Estimation (ALE first showed a set of predominantly left-hemispheric regions shared by the various creativity tasks examined. These regions included the caudal lateral prefrontal cortex (PFC, the medial and lateral rostral PFC, and the inferior parietal and posterior temporal cortices. Further analyses showed that tasks involving the combination of remote information (combination tasks activated more anterior areas of the lateral PFC than tasks involving the free generation of unusual responses (unusual generation tasks, although both types of tasks shared caudal prefrontal areas. In addition, verbal and non-verbal tasks involved the same regions in the left caudal prefrontal, temporal, and parietal areas, but also distinct domain-oriented areas. Taken together, these findings suggest that several frontal and parieto-temporal regions may support cognitive processes shared by diverse creativity tasks, and that some regions may be specialized for distinct types of processes. In particular, the lateral PFC appeared to be organized along a rostro-caudal axis, with rostral regions involved in combining ideas creatively and more posterior regions involved in freely generating novel ideas.

  6. [Comparative anatomic studies of the vomeronasal complex and the rostral palate of various mammals].

    Science.gov (United States)

    Wöhrmann-Repenning, A

    1984-01-01

    The structures of the rostral palate in regard to the vomeronasal complex of different species of mammals were studied. In all cases, we find a very interesting system of furrows which preserves a connection between the nasopalatine ducts and the preoral surroundings. For rodents, lagomorphs, Solenodon, Setifer, and Echinops, we find a special situation in this part of the palate. Here the incisors are not separated by a diastema nor the oral openings of the nasopalatine ducts are overgrown by a bipartite caudal branch of the rhinarium. The results of the anatomic studies of the vomeronasal complex and the rostral palate of the mammals investigated are discussed: First of all, some elements of the vomeronasal complex needed to be analysed in regard to structure and nomenclature, specifically the cartilago paraseptalis with its outer bar, the cartilago ductus nasopalatini and the cartilago palatina. Because of 2 criterions, the vomeronasal complex could be classified as either primitive or progressive. We find a primitive one in Didelphis, Tupaia, Solenodon, Oryctolagus, and all rodents. In contrast, the other insectivores studied and all primates show progressive structures at their vomeronasal complex. Finally, conclusions in regard to the function of the organs of Jacobson are derived from these studies. The significance of the "flehmen" mechanism for the functioning of the organs is questioned.

  7. The rostral migratory stream and olfactory system: smell, disease and slippery cells.

    Science.gov (United States)

    Curtis, Maurice A; Monzo, Hector J; Faull, Richard L M

    2009-01-01

    In the mammalian brain, olfaction is an important sense that is used to detect odors of different kinds that can warn of off food, to produce a mothering instinct in a flock or group of animals, and to warn of danger such as fire or poison. The olfactory system is made up of a long-distance rostral migratory stream that arises from the subventricular zone in the wall of the lateral ventricle, mainly comprises neuroblasts, and stretches all the way through the basal forebrain to terminate in the olfactory bulb. The olfactory bulb receives a constant supply of new neurons that allow ongoing integration of new and different smells, and these are integrated into either the granule cell layer or the periglomerular layer. The continuous turnover of neurons in the olfactory bulb allows us to study the proliferation, migration, and differentiation of neurons and their application in therapies for neurodegenerative diseases. In this chapter, we will examine the notion that the olfactory system might be the route of entry for factors that cause or contribute to neurodegeneration in the central nervous system. We will also discuss the enzymes that may be involved in the addition of polysialic acid to neural cell adhesion molecule, which is vital for allowing the neuroblasts to move through the rostral migratory stream. Finally, we will discuss a possible role of endosialidases for removing polysialic acid from neural cell adhesion molecules, which causes neuroblasts to stop migrating and terminally differentiate into olfactory bulb interneurons.

  8. Calcium-dependent plateau potentials in rostral ambiguus neurons in the newborn mouse brain stem in vitro

    DEFF Research Database (Denmark)

    Rekling, J C; Feldman, J L

    1997-01-01

    Calcium-dependent plateau potentials in rostral ambiguus neurons in the newborn mouse brain stem in vitro. J. Neurophysiol. 78: 2483-2492, 1997. The nucleus ambiguus contains vagal and glossopharyngeal motoneurons and preganglionic neurons involved in respiration, swallowing, vocalization......, and control of heart beat. Here we show that the rostral compact formation's ambiguus neurons, which control the esophageal phase of swallowing, display calcium-dependent plateau potentials in response to tetanic orthodromic stimulation or current injection. Whole cell recordings were made from visualized...... neurons in the rostral nucleus ambiguus using a slice preparation from the newborn mouse. Biocytin-labeling revealed dendritic trees with pronounced rostrocaudal orientations confined to the nucleus ambiguus, a morphological profile matching that of vagal motoneurons projecting to the esophagus. Single...

  9. A brain slice culture model for studies of endogenous and exogenous precursor cell migration in the rostral migratory stream

    DEFF Research Database (Denmark)

    Tanvig, Mette; Blaabjerg, Morten; Andersen, Rikke K

    2009-01-01

    The rostral migratory stream (RMS) is the main pathway by which newly born subventricular zone (SVZ) cells reach the olfactory bulb (OB) in rodents. This migration has been well studied in vivo, but an organotypic in vitro model would facilitate more experimental investigations. Here we introduce...... a slice culture preparation of the rat forebrain including en suite the rostral part of the lateral ventricle, the RMS and the OB. The preparation was validated with regard to endogenous cell proliferation and migration by tracking bromodeoxyuridine (BrdU)-labelled cells in newly established and 3 and 6...... week old cultures. For testing the migratory abilities of exogenous precursor cells, rat SVZ neurospheres and human neural (HNS1 cells) and mesenchymal (hMSC-TERT) stem cell lines were micrografted to the rostral SVZ of 1 and 7 day old cultures. Two weeks later graft derivatives were identified...

  10. Reduced thalamic volume in preterm infants is associated with abnormal white matter metabolism independent of injury

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    Wisnowski, Jessica L. [Children' s Hospital Los Angeles, Department of Radiology, Los Angeles, CA (United States); University of Pittsburgh, Department of Pediatric Radiology, Children' s Hospital of Pittsburgh of UPMC, Pittsburgh, PA (United States); University of Southern California, Brain and Creativity Institute, Los Angeles, CA (United States); Ceschin, Rafael C. [University of Pittsburgh, Department of Pediatric Radiology, Children' s Hospital of Pittsburgh of UPMC, Pittsburgh, PA (United States); University of Pittsburgh, Department of Biomedical Informatics, Pittsburgh, PA (United States); Choi, So Young [University of Southern California, Brain and Creativity Institute, Los Angeles, CA (United States); Schmithorst, Vincent J. [University of Pittsburgh, Department of Pediatric Radiology, Children' s Hospital of Pittsburgh of UPMC, Pittsburgh, PA (United States); Painter, Michael J. [University of Pittsburgh, Department of Pediatrics, Division of Neurology, Childrens Hospital of Pittsburgh of UPMC, Pittsburgh, PA (United States); Nelson, Marvin D. [Children' s Hospital Los Angeles, Department of Radiology, Los Angeles, CA (United States); Blueml, Stefan [Children' s Hospital Los Angeles, Department of Radiology, Los Angeles, CA (United States); Rudi Schulte Research Institute, Santa Barbara, CA (United States); Panigrahy, Ashok [Children' s Hospital Los Angeles, Department of Radiology, Los Angeles, CA (United States); University of Pittsburgh, Department of Pediatric Radiology, Children' s Hospital of Pittsburgh of UPMC, Pittsburgh, PA (United States)

    2015-05-01

    Altered thalamocortical development is hypothesized to be a key substrate underlying neurodevelopmental disabilities in preterm infants. However, the pathogenesis of this abnormality is not well-understood. We combined magnetic resonance spectroscopy of the parietal white matter and morphometric analyses of the thalamus to investigate the association between white matter metabolism and thalamic volume and tested the hypothesis that thalamic volume would be associated with diminished N-acetyl-aspartate (NAA), a measure of neuronal/axonal maturation, independent of white matter injury. Data from 106 preterm infants (mean gestational age at birth: 31.0 weeks ± 4.3; range 23-36 weeks) who underwent MR examinations under clinical indications were included in this study. Linear regression analyses demonstrated a significant association between parietal white matter NAA concentration and thalamic volume. This effect was above and beyond the effect of white matter injury and age at MRI and remained significant even when preterm infants with punctate white matter lesions (pWMLs) were excluded from the analysis. Furthermore, choline, and among the preterm infants without pWMLs, lactate concentrations were also associated with thalamic volume. Of note, the associations between NAA and choline concentration and thalamic volume remained significant even when the sample was restricted to neonates who were term-equivalent age or older. These observations provide convergent evidence of a neuroimaging phenotype characterized by widespread abnormal thalamocortical development and suggest that the pathogenesis may involve impaired axonal maturation. (orig.)

  11. Membrane Bistability in Thalamic Reticular Neurons During Spindle Oscillations

    Science.gov (United States)

    Fuentealba, Pablo; Timofeev, Igor; Bazhenov, Maxim; Sejnowski, Terrence J.; Steriade, Mircea

    2010-01-01

    The thalamic reticular (RE) nucleus is a major source of inhibition in the thalamus. It plays a crucial role in regulating the excitability of thalamocortical networks and in generating some sleep rhythms. Current-clamp intracellular recordings of RE neurons in cats under barbiturate anesthesia revealed the presence of membrane bistability in ~20% of neurons. Bistability consisted of two alternate membrane potentials, separated by ~17–20 mV. While non-bistable (common) RE neurons fired rhythmic spike-bursts during spindles, bistable RE neurons fired tonically, with burst modulation, throughout spindle sequences. Bistability was strongly voltage dependent and only expressed under resting conditions (i.e. no current injection). The transition from the silent to the active state was a regenerative event that could be activated by brief depolarization, whereas brief hyperpolarizations could switch the membrane potential from the active to the silent state. These effects outlasted the current pulses. Corticothalamic stimulation could also switch the membrane potential from silent to active states. Addition of QX-314 in the recording micropipette either abolished or disrupted membrane bistability, suggesting INa(p) to be responsible for its generation. Thalamocortical cells presented various patterns of spindling that reflected the membrane bistability in RE neurons. Finally, experimental data and computer simulations predicted a role for RE neurons’ membrane bistability in inducing various patterns of spindling in target thalamocortical cells. We conclude that membrane bistability of RE neurons is an intrinsic property, likely generated by INa(p) and modulated by cortical influences, as well as a factor that determines different patterns of spindle rhythms in thalamocortical neurons. PMID:15331618

  12. Frontotemporal dementia with severe thalamic involvement : a clinical and neuropathological study

    Directory of Open Access Journals (Sweden)

    Radanovic Márcia

    2003-01-01

    Full Text Available Frontotemporal dementia (FTD is the third-leading cause of cortical dementia after Alzheimer's disease and Lewy body dementia, and is characterized by a dementia where behavioral disturbances are prominent and appear early in the course of the disease. We report the case of a 58 year-old man affected by dementia with behavioral disturbances, in addition to rigid-hypokinetic and a lower motor neuron syndrome that were present at later stages of the illness. Neuroimaging studies showed frontotemporal atrophy. Neuropathological studies revealed intense thalamic neuronal loss and astrocytic gliosis, as well as moderate frontotemporal neuronal loss, astrocytosis and spongiform degeneration. Thalamic degeneration has previously been described among the wide group of neuropathological features of FTD. The aim of the present study is to show the clinical and neuropathological aspects of thalamic degeneration in FTD, along with its role in behavioral disturbances, a common finding in this condition.

  13. Accelerated forgetting of contextual details due to focal medio-dorsal thalamic lesion

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    Sicong eTu

    2014-09-01

    Full Text Available Effects of thalamic nuclei damage and related white matter tracts on memory performance are still debated. This is particularly evident for the medio-dorsal thalamus which has been less clear in predicting amnesia than anterior thalamus changes. The current study addresses this issue by assessing 7 thalamic stroke patients with consistent unilateral lesions focal to the left medio-dorsal nuclei for immediate and delayed memory performance on standard visual and verbal tests of anterograde memory, and over the long-term (> 24 hrs on an object-location associative memory task. Thalamic patients showed selective impairment to delayed recall, but intact recognition memory. Patients also showed accelerated forgetting of contextual information after a 24 hour delay, compared to controls. Importantly, the mammillothalamic tract was intact in all patients, which suggests a role for the medio-dorsal nuclei in recall and early consolidation memory processes.

  14. Autobiogutobiographical amnesia and cognltive disorder resulgting from bilateral severe thalamic infarction Two cases reports

    Institute of Scientific and Technical Information of China (English)

    Ytt Kai; Yu Feng Qi; Lei Zheng Lin; Zhang Jun

    2000-01-01

    Objective To report two cases of patients with bilateral severe thalamic infarction.which showed autobiographical amnesia and cognitive disorders and to shed light on the mechanisms underlying thc retrograde amenesia. Method The two cases were studied clinically, CT and MRI were performed also, Language and neuropsychological tests were evaluated. Results Two patients with a chronic amnesia and cogntive disorders resulting from bilateral paramedian thalamic infarction showed a pattern of retrograde amnesia personally relevent autobiographical memory were prefoundly impaired .Whereas about the famous people and public events were relatively impaired. The patients almost had no thalamic aphasia.The events the one described showed spontaneously confabulated. Conclusion We think a probable explanation that the disorders at the thematic retrieval fiomwork ievel of memory and the information reconstruction due to a disconnetion of frontal and medial temperal memory systems.

  15. Validation of connectivity-based thalamic segmentation with direct electrophysiologic recordings from human sensory thalamus.

    Science.gov (United States)

    Elias, W Jeffrey; Zheng, Zhong A; Domer, Paul; Quigg, Mark; Pouratian, Nader

    2012-02-01

    Connectivity-based segmentation has been used to identify functional gray matter subregions that are not discernable on conventional magnetic resonance imaging. However, the accuracy and reliability of this technique has only been validated using indirect means. In order to provide direct electrophysiologic validation of connectivity-based thalamic segmentations within human subjects, we assess the correlation of atlas-based thalamic anatomy, connectivity-based thalamic maps, and somatosensory evoked thalamic potentials in two adults with medication-refractory epilepsy who were undergoing intracranial EEG monitoring with intrathalamic depth and subdural cortical strip electrodes. MRI with atlas-derived localization was used to delineate the anatomic boundaries of the ventral posterolateral (VPL) nucleus of the thalamus. Somatosensory evoked potentials with intrathalamic electrodes physiologically identified a discrete region of phase reversal in the ventrolateral thalamus. Finally, DTI was obtained so that probabilistic tractography and connectivity-based segmentation could be performed to correlate the region of thalamus linked to sensory areas of the cortex, namely the postcentral gyrus. We independently utilized these three different methods in a blinded fashion to localize the "sensory" thalamus, demonstrating a high-degree of reproducible correlation between electrophysiologic and connectivity-based maps of the thalamus. This study provides direct electrophysiologic validation of probabilistic tractography-based thalamic segmentation. Importantly, this study provides an electrophysiological basis for using connectivity-based segmentation to further study subcortical anatomy and physiology while also providing the clinical basis for targeting deep brain nuclei with therapeutic stimulation. Finally, these direct recordings from human thalamus confirm early inferences of a sensory thalamic component of the N18 waveform in somatosensory evoked potentials.

  16. Impairments of thalamic resting-state functional connectivity in patients with chronic tinnitus

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian [Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing (China); Chen, Yu-Chen [Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing (China); Center for Hearing and Deafness, University at Buffalo, State University of New York, Buffalo, NY (United States); Feng, Xu [Department of Otolaryngology, Zhongda Hospital, Medical School, Southeast University, Nanjing (China); Yang, Ming; Liu, Bin; Qian, Cheng [Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing (China); Wang, Jian [Department of Physiology, Southeast University, Nanjing (China); School of Human Communication Disorders, Dalhousie University, Halifax, NS (Canada); Salvi, Richard [Center for Hearing and Deafness, University at Buffalo, State University of New York, Buffalo, NY (United States); Teng, Gao-Jun, E-mail: gjteng@vip.sina.com [Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School, Southeast University, Nanjing (China)

    2015-07-15

    Highlights: • Tinnitus patients have aberrant thalamic connectivity to many brain regions. • Decreased thalamic connectivity is linked with tinnitus characteristics. • Thalamocortical connectivity disturbances can reflect tinnitus-related networks. - Abstract: Purpose: The phantom sound of tinnitus is believed to arise from abnormal functional coupling between the thalamus and cerebral cortex. To explore this hypothesis, we used resting-state functional magnetic resonance imaging (fMRI) to compare the degree of thalamocortical functional connectivity in chronic tinnitus patients and controls. Materials and methods: Resting-state fMRI scans were obtained from 31 chronic tinnitus patients and 33 well-matched healthy controls. Thalamocortical functional connectivity was characterized using a seed-based whole-brain correlation method. The resulting thalamic functional connectivity measures were correlated with other clinical data. Results: We found decreased functional connectivity between the seed region in left thalamus and right middle temporal gyrus (MTG), right middle orbitofrontal cortex, left middle frontal gyrus, right precentral gyrus, and bilateral calcarine cortex. Decreased functional connectivity was detected between the seed in the right thalamus and the left superior temporal gyrus (STG), left amygdala, right superior frontal gyrus, left precentral gyrus, and left middle occipital gyrus. Tinnitus distress correlated negatively with thalamic functional connectivity in right MTG; tinnitus duration correlated negatively with thalamic functional connectivity in left STG. Increased functional connectivity between the bilateral thalamus and a set of regions were also observed. Conclusions: Chronic tinnitus patients have disrupted thalamocortical functional connectivity to selected brain regions which is associated with specific tinnitus characteristics. Resting-state thalamic functional connectivity disturbances may play an important role in

  17. Leading role of thalamic over cortical neurons during postinhibitory rebound excitation

    Science.gov (United States)

    Grenier, F.; Timofeev, I.; Steriade, M.

    1998-01-01

    The postinhibitory rebound excitation is an intrinsic property of thalamic and cortical neurons that is implicated in a variety of normal and abnormal operations of neuronal networks, such as slow or fast brain rhythms during different states of vigilance as well as seizures. We used dual simultaneous intracellular recordings of thalamocortical neurons from the ventrolateral nucleus and neurons from the motor cortex, together with thalamic and cortical field potentials, to investigate the temporal relations between thalamic and cortical events during the rebound excitation that follows prolonged periods of stimulus-induced inhibition. Invariably, the rebound spike-bursts in thalamocortical cells occurred before the rebound depolarization in cortical neurons and preceded the peak of the depth-negative, rebound field potential in cortical areas. Also, the inhibitory-rebound sequences were more pronounced and prolonged in cortical neurons when elicited by thalamic stimuli, compared with cortical stimuli. The role of thalamocortical loops in the rebound excitation of cortical neurons was shown further by the absence of rebound activity in isolated cortical slabs. However, whereas thalamocortical neurons remained hyperpolarized after rebound excitation, because of the prolonged spike-bursts in inhibitory thalamic reticular neurons, the rebound depolarization in cortical neurons was prolonged, suggesting the role of intracortical excitatory circuits in this sustained activity. The role of intrathalamic events in triggering rebound cortical activity should be taken into consideration when analyzing information processes at the cortical level; at each step, corticothalamic volleys can set into action thalamic inhibitory neurons, leading to rebound spike-bursts that are transferred back to the cortex, thus modifying cortical activities. PMID:9811903

  18. Rostral horn evolution among agamid lizards of the genus ceratophora endemic to Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Schulte II, James A.; Macey, J. Robert; Pethiyagoda, Rohan; Larson, Allan

    2001-07-10

    The first phylogenetic hypothesis for the Sri Lankan agamid lizard genus Ceratophora is presented based on 1670 aligned base positions (472 parsimony informative) of mitochondrial DNA sequences, representing coding regions for eight tRNAs, ND2, and portions of ND1 and COI. Phylogenetic analysis reveals multiple origins and possibly losses of rostral horns in the evolutionary history of Ceratophora. Our data suggest a middle Miocene origin of Ceratophora with the most recent branching of recognized species occurring at the Pliocene/Pleistocene boundary. Haplotype divergence suggests that an outgroup species, Lyriocephalus scutatus, dates at least to the Pliocene. These phylogenetic results provide a framework for comparative studies of the behavioral ecological importance of horn evolution in this group.

  19. Lucid dreams, an atypical sleep disturbance in anterior and mediodorsal thalamic strokes.

    Science.gov (United States)

    Sagnier, S; Coulon, P; Chaufton, C; Poli, M; Debruxelles, S; Renou, P; Rouanet, F; Olindo, S; Sibon, I

    2015-11-01

    Cognitive, affective, and behavioural disturbances are commonly reported following thalamic strokes. Conversely, sleep disorders are rarely reported in this context. Herein, we report the cases of two young patients admitted for an ischemic stroke located in the territories of the left pre-mammillary and paramedian arteries. Together with aphasia, memory complaint, impaired attention and executive functions, they reported lucid dreams with catastrophic content or conflicting situations. Lucid dreams are an atypical presentation in thalamic strokes. These cases enlarge the clinical spectrum of sleep-wake disturbances potentially observed after an acute cerebrovascular event. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  20. Apathy, cognitive dysfunction and impaired social cognition in a patient with bilateral thalamic infarction.

    Science.gov (United States)

    Ioannidis, Anestis E; Kimiskidis, Vasilios K; Loukopoulou, Eleni; Geroukis, Triantafyllos; Vlaikidis, Nikolaos; Kosmidis, Mary H

    2013-01-01

    We describe the case of a patient with bilateral thalamic lesions due to brain infarcts in the paramedian thalamic artery territories. The patient demonstrated symptoms of apathy (e.g., loss of initiative and interest in others, poor motivation, flattened affect). Neuropsychological assessment 3 and 5 years post-infarct revealed severe deficits in verbal and non-verbal immediate and delayed memory, attention, and executive functioning, with minimal improvement over time. Also, he demonstrated difficulties in social cognition (i.e., perception of facial expressions of others and of sarcasm). These findings are discussed and interpreted in light of current theories regarding the neurobiological substrate of apathy.

  1. Allometric growth of the trunk leads to the rostral shift of the pelvic fin in teleost fishes.

    Science.gov (United States)

    Murata, Yumie; Tamura, Mika; Aita, Yusuke; Fujimura, Koji; Murakami, Yasunori; Okabe, Masataka; Okada, Norihiro; Tanaka, Mikiko

    2010-11-01

    The pelvic fin position among teleost fishes has shifted rostrally during evolution, resulting in diversification of both behavior and habitat. We explored the developmental basis for the rostral shift in pelvic fin position in teleost fishes using zebrafish (abdominal pelvic fins) and Nile tilapia (thoracic pelvic fins). Cell fate mapping experiments revealed that changes in the distribution of lateral plate mesodermal cells accompany the trunk-tail protrusion. Presumptive pelvic fin cells are originally located at the body wall adjacent to the anterior limit of hoxc10a expression in the spinal cord, and their position shifts rostrally as the trunk grows. We then showed that the differences in pelvic fin position between zebrafish and Nile tilapia were not due to changes in expression or function of gdf11. We also found that hox-independent motoneurons located above the pelvic fins innervate into the pelvic musculature. Our results suggest that there is a common mechanism among teleosts and tetrapods that controls paired appendage positioning via gdf11, but in teleost fishes the position of prospective pelvic fin cells on the yolk surface shifts as the trunk grows. In addition, teleost motoneurons, which lack lateral motor columns, innervate the pelvic fins in a manner independent of the rostral-caudal patterns of hox expression in the spinal cord. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. The atypical cadherin Celsr1 functions non-cell autonomously to block rostral migration of facial branchiomotor neurons in mice.

    Science.gov (United States)

    Glasco, Derrick M; Pike, Whitney; Qu, Yibo; Reustle, Lindsay; Misra, Kamana; Di Bonito, Maria; Studer, Michele; Fritzsch, Bernd; Goffinet, André M; Tissir, Fadel; Chandrasekhar, Anand

    2016-09-01

    The caudal migration of facial branchiomotor (FBM) neurons from rhombomere (r) 4 to r6 in the hindbrain is an excellent model to study neuronal migration mechanisms. Although several Wnt/Planar Cell Polarity (PCP) components are required for FBM neuron migration, only Celsr1, an atypical cadherin, regulates the direction of migration in mice. In Celsr1 mutants, a subset of FBM neurons migrates rostrally instead of caudally. Interestingly, Celsr1 is not expressed in the migrating FBM neurons, but rather in the adjacent floor plate and adjoining ventricular zone. To evaluate the contribution of different expression domains to neuronal migration, we conditionally inactivated Celsr1 in specific cell types. Intriguingly, inactivation of Celsr1 in the ventricular zone of r3-r5, but not in the floor plate, leads to rostral migration of FBM neurons, greatly resembling the migration defect of Celsr1 mutants. Dye fill experiments indicate that the rostrally-migrated FBM neurons in Celsr1 mutants originate from the anterior margin of r4. These data suggest strongly that Celsr1 ensures that FBM neurons migrate caudally by suppressing molecular cues in the rostral hindbrain that can attract FBM neurons.

  3. The pressor effect of angiotensin-(1-7 in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

    Directory of Open Access Journals (Sweden)

    Rita C. Oliveira

    2013-01-01

    Full Text Available OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7 in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7 (25 pmol was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium or a vasopressin V1 receptor antagonist [d(CH25 -Tyr(Me-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7 (16 ± 2 mmHg, n = 12, which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7 at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7 at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7 triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.

  4. A stereological study of the mediodorsal thalamic nucleus in Down syndrome

    DEFF Research Database (Denmark)

    Karlsen, A S; Korbo, S; Uylings, H B M

    2014-01-01

    The total number of neurons and glial cells in the mediodorsal thalamic (MDT) nucleus of four aged females with Down syndrome (DS; mean age 69years) was estimated and compared to six age- and sex-matched controls. The MDT nucleus was delineated on coronal sections, and cell numbers (large and small...

  5. Perinatal development of the mammillothalamic tract and innervation of the anterior thalamic nuclei.

    Science.gov (United States)

    Alpeeva, E V; Makarenko, I G

    2009-01-12

    Axonal projections originating from the mammillary bodies represent important pathways that are essential for spatial information processing. Mammillothalamic tract is one of the main efferent projection systems of the mammillary body belonging to the limbic "Papez circuit". This study was aimed to describe the schedule of the mammillothalamic tract development in the rat using carbocyanine dye tracing. It was shown for the first time that fibers of the mammillothalamic tract being the collaterals of the mammillotegmental tract axons start bifurcating from the mammillotegmental tract on E17. The axons of the mammillothalamic tract grow simultaneously and reach the ventral region of the anterior thalamus where they form first terminal arborizations on E20-E21. Ipsilateral projections from the medial mammillary nucleus to the anteromedial and anteroventral thalamic nuclei develop from E20 to P6. Bilateral projections from the lateral mammillary nucleus to the anterodorsal thalamic nuclei develop later, on P3-P6, after the formation of the thalamic decussation of the mammillary body axons. Unique spatial and temporal pattern of the perinatal development of ascending mammillary body projections to the anterior thalamic nuclei may reflect the importance of these connections within the limbic circuitry.

  6. Anterior Thalamic Lesions Alter Both Hippocampal-Dependent Behavior and Hippocampal Acetylcholine Release in the Rat

    Science.gov (United States)

    Savage, Lisa M.; Hall, Joseph M.; Vetreno, Ryan P.

    2011-01-01

    The anterior thalamic nuclei (ATN) are important for learning and memory as damage to this region produces a persistent amnestic syndrome. Dense connections between the ATN and the hippocampus exist, and importantly, damage to the ATN can impair hippocampal functioning. Acetylcholine (ACh) is a key neurotransmitter in the hippocampus, and in vivo…

  7. Silent diabetes mellitus, periodontitis and a new case of thalamic abscess.

    Science.gov (United States)

    Karageorgiou, Ioannis; Chandler, Christopher; Whyte, Martin Brunel

    2014-07-21

    Brain abscess is an unusual complication of uncontrolled diabetes. A solitary thalamic abscess is an uncommon type of brain abscess. We report a case of thalamic abscess, whereupon diabetes mellitus and periodontitis were diagnosed. The diagnosis and management of thalamic abscess, and the interplay of type 2 diabetes and periodontitis are discussed. A 56-year-old, Caucasian, man with no medical or travel history, presented with 5-day symptoms of meningeal irritation. Body mass index 30.6 kg/m(2). CT demonstrated a solitary midline lesion with neoplasia as a differential diagnosis. It was biopsied and cultures grew Streptococcus milleri. He was treated by stereotactic puncture, external drainage and targeted intrathecal and systemic antibiotic therapy. HIV negative but glycated haemoglobin (HbA1c) 10.7% (93 mmol/mol). Dental examination revealed a small molar abscess. Radiological resolution of the thalamic abscess occurred within 2 months. Diabetes improved with 7 weeks of insulin, and maintained on metformin, HbA1c 6.9% (51 mmol/mol). There was no residual neurological disability. 2014 BMJ Publishing Group Ltd.

  8. Thalamic cholinergic innervation is spared in Alzheimer disease compared to Parkinsonian disorders

    Science.gov (United States)

    Kotagal, Vikas; Müller, Martijn L.T.M.; Kaufer, Daniel I.; Koeppe, Robert A.; Bohnen, Nicolaas I.

    2012-01-01

    OBJECTIVE There are two major sources of cholinergic projections in the brain. The nucleus basalis of Meynert provides the principal cholinergic input of the cortical mantle and the pedunculopontine nucleus-laterodorsal tegmental complex (PPN-LDTC; hereafter referred to as PPN) provides the major cholinergic input to the thalamus. Cortical cholinergic denervation has previously been shown to be part of Alzheimer and parkinsonian dementia but there is less information about subcortical thalamic cholinergic denervation. We investigated thalamic cholinergic afferent integrity by measuring PPN-Thalamic (PPN-Thal) acetylcholinesterase (AChE) activity via PET imaging in Alzheimer (AD), Parkinson disease without dementia (PD), Parkinson disease with dementia (PDD) and dementia with Lewy bodies (DLB). METHODS AD (n=13; mean age 75.4±5.5), PD (n=11; age 71.4±6.4), PDD (n=6; age 70.8±4.7), DLB (n=6; age 68.0±8.6) and normal controls (NC; n=14; age 69.0±7.5) subjects underwent AChE [11C]-methyl-4-piperidinyl propionate (PMP) PET imaging. PPN-Thal PET data were analyzed using the Nagatsuka method. RESULTS There were no significant differences in mean age between the groups (F=1.86, p=0.134). Kruskal-Wallis testing demonstrated a significant group effect for PPN-Thal AChE hydrolysis rates (F=9.62, P<0.0001). Compared to NC, reduced thalamic k3 hydrolysis rate was noted in subjects with PDD (−19.8%; AChE k3 hydrolysis rates 0.1072±0.0143 min−1), DLB (−17.4%; 0.1103±0.0112 min−1) and PD (−12.8%; 0.1165±0.0114 min−1). Each of these 3 subgroups were statistically different from AD subjects (−0.7%; 0.1326±0.0095 min−1) who showed relatively spared thalamic k3 hydrolysis rates which were comparable to NC (0.1336±0.0142 min−1). CONCLUSIONS Thalamic cholinergic denervation is present in PD, PDD, and DLB but not in AD. Neurodegenerative involvement of thalamic cholinergic afferent projections may contribute to disease-specific motor and cognitive

  9. Flexible Use of Predictive Cues beyond the Orbitofrontal Cortex: Role of the Submedius Thalamic Nucleus.

    Science.gov (United States)

    Alcaraz, Fabien; Marchand, Alain R; Vidal, Elisa; Guillou, Alexandre; Faugère, Angélique; Coutureau, Etienne; Wolff, Mathieu

    2015-09-23

    The orbitofrontal cortex (OFC) is known to play a crucial role in learning the consequences of specific events. However, the contribution of OFC thalamic inputs to these processes is largely unknown. Using a tract-tracing approach, we first demonstrated that the submedius nucleus (Sub) shares extensive reciprocal connections with the OFC. We then compared the effects of excitotoxic lesions of the Sub or the OFC on the ability of rats to use outcome identity to direct responding. We found that neither OFC nor Sub lesions interfered with the basic differential outcomes effect. However, more specific tests revealed that OFC rats, but not Sub rats, were disproportionally relying on the outcome, rather than on the discriminative stimulus, to guide behavior, which is consistent with the view that the OFC integrates information about predictive cues. In subsequent experiments using a Pavlovian contingency degradation procedure, we found that both OFC and Sub lesions produced a severe deficit in the ability to update Pavlovian associations. Altogether, the submedius therefore appears as a functionally relevant thalamic component in a circuit dedicated to the integration of predictive cues to guide behavior, previously conceived as essentially dependent on orbitofrontal functions. Significance statement: In the present study, we identify a largely unknown thalamic region, the submedius nucleus, as a new functionally relevant component in a circuit supporting the flexible use of predictive cues. Such abilities were previously conceived as largely dependent on the orbitofrontal cortex. Interestingly, this echoes recent findings in the field showing, in research involving an instrumental setup, an additional involvement of another thalamic nuclei, the parafascicular nucleus, when correct responding requires an element of flexibility (Bradfield et al., 2013a). Therefore, the present contribution supports the emerging view that limbic thalamic nuclei may contribute critically to

  10. Thalamic neuron models encode stimulus information by burst-size modulation

    Directory of Open Access Journals (Sweden)

    Daniel Henry Elijah

    2015-09-01

    Full Text Available Thalamic neurons have been long assumed to fire in tonic mode during perceptive states, and in burst mode during sleep and unconsciousness. However, recent evidence suggests that bursts may also be relevant in the encoding of sensory information. Here we explore the neural code of such thalamic bursts. In order to assess whether the burst code is generic or whether it depends on the detailed properties of each bursting neuron, we analyzed two neuron models incorporating different levels of biological detail. One of the models contained no information of the biophysical processes entailed in spike generation, and described neuron activity at a phenomenological level. The second model represented the evolution of the individual ionic conductances involved in spiking and bursting, and required a large number of parameters. We analyzed the models' input selectivity using reverse correlation methods and information theory. We found that n-spike bursts from both models transmit information by modulating their spike count in response to changes to instantaneous input features, such as slope, phase, amplitude, etc. The stimulus feature that is most efficiently encoded by bursts, however, need not coincide with one of such classical features. We therefore searched for the optimal feature among all those that could be expressed as a linear transformation of the time-dependent input current. We found that bursting neurons transmitted 6 times more information about such more general features. The relevant events in the stimulus were located in a time window spanning ~100 ms before and ~20 ms after burst onset. Most importantly, the neural code employed by the simple and the biologically realistic models was largely the same, implying that the simple thalamic neuron model contains the essential ingredients that account for the computational properties of the thalamic burst code. Thus, our results suggest the n-spike burst code is a general property of

  11. Disrupted thalamic resting-state functional connectivity in patients with minimal hepatic encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Rongfeng [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing 210002 (China); Zhang, Long Jiang, E-mail: kevinzhanglongjiang@yahoo.com.cn [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing 210002 (China); Zhong, Jianhui [Department of Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang, Zhiqiang; Ni, Ling; Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing 210002 (China); Lu, Guang Ming, E-mail: cjr.luguangming@vip.163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing 210002 (China)

    2013-05-15

    Background and purpose: Little is known about the role of thalamus in the pathophysiology of minimal hepatic encephalopathy (MHE). The purpose of this study was to investigate whether the thalamic functional connectivity was disrupted in cirrhotic patients with MHE by using resting-state functional magnetic resonance imaging (rs-fMRI). Materials and Methods: Twenty seven MHE patients and twenty seven age- and gender- matched healthy controls participated in the rs-fMRI scans. The functional connectivity of 11 thalamic nuclei were characterized by using a standard seed-based whole-brain correlation method and compared between MHE patients and healthy controls. Pearson correlation analysis was performed between the thalamic functional connectivity and venous blood ammonia levels/neuropsychological tests scores of patients. Results: The ventral anterior nucleus (VAN) and the ventral posterior medial nucleus (VPMN) in each side of thalamus showed abnormal functional connectivities in MHE. Compared with healthy controls, MHE patients demonstrated significant decreased functional connectivity between the right/left VAN and the bilateral putamen/pallidum, inferior frontal gyri, insula, supplementary motor area, right middle frontal gyrus, medial frontal gyrus. In addition, MHE patients showed significantly decreased functional connectivity with the right/left VPMN in the bilateral middle temporal gyri (MTG), temporal lobe, and right superior temporal gyrus. The venous blood ammonia levels of MHE patients negatively correlated with the functional connectivity between the VAN and the insula. Number connecting test scores showed negative correlation with the functional connectivity between the VAN and the insula, and between the VPMN and the MTG. Conclusion: MHE patients had disrupted thalamic functional connectivity, which mainly located in the bilateral ventral anterior nuclei and ventral posterior medial nuclei. The decreased connectivity between thalamus and many

  12. Thalamic neuron models encode stimulus information by burst-size modulation.

    Science.gov (United States)

    Elijah, Daniel H; Samengo, Inés; Montemurro, Marcelo A

    2015-01-01

    Thalamic neurons have been long assumed to fire in tonic mode during perceptive states, and in burst mode during sleep and unconsciousness. However, recent evidence suggests that bursts may also be relevant in the encoding of sensory information. Here, we explore the neural code of such thalamic bursts. In order to assess whether the burst code is generic or whether it depends on the detailed properties of each bursting neuron, we analyzed two neuron models incorporating different levels of biological detail. One of the models contained no information of the biophysical processes entailed in spike generation, and described neuron activity at a phenomenological level. The second model represented the evolution of the individual ionic conductances involved in spiking and bursting, and required a large number of parameters. We analyzed the models' input selectivity using reverse correlation methods and information theory. We found that n-spike bursts from both models transmit information by modulating their spike count in response to changes to instantaneous input features, such as slope, phase, amplitude, etc. The stimulus feature that is most efficiently encoded by bursts, however, need not coincide with one of such classical features. We therefore searched for the optimal feature among all those that could be expressed as a linear transformation of the time-dependent input current. We found that bursting neurons transmitted 6 times more information about such more general features. The relevant events in the stimulus were located in a time window spanning ~100 ms before and ~20 ms after burst onset. Most importantly, the neural code employed by the simple and the biologically realistic models was largely the same, implying that the simple thalamic neuron model contains the essential ingredients that account for the computational properties of the thalamic burst code. Thus, our results suggest the n-spike burst code is a general property of thalamic neurons.

  13. Lack of serotonin reuptake during brain development alters rostral raphe-prefrontal network formation

    Directory of Open Access Journals (Sweden)

    Josefine Storm Witteveen

    2013-10-01

    Full Text Available Besides its ‘classical’ neurotransmitter function, serotonin (5-HT has been found to also act as a neurodevelopmental signal. During development, the 5-HT projection system represents one of the earliest neurotransmitter systems to innervate the brain. One of the targets of the 5-HT projection system, originating in the brainstem raphe nuclei, is the medial prefrontal cortex (mPFC, an area involved in higher cognitive functions and important in the etiology of many neurodevelopmental disorders. Little is known however about the exact role of 5-HT and its signaling molecules in the formation of the raphe-prefrontal network. Using explant essays, we here studied the role of the 5-HT transporter (5-HTT, an important modulator of the 5-HT signal, in rostral raphe-prefrontal network formation. We found that the chemotrophic nature of the interaction between the origin (rostral raphe cluster and a target (mPFC of the 5-HT projection system was affected in rats lacking the 5-HTT (5-HTT-/-. While 5-HTT deficiency did not affect the dorsal raphe 5-HT-positive outgrowing neurites, the median raphe 5-HT neurites switched from a strong repulsive to an attractive interaction when co-cultured with the mPFC. Furthermore, the fasciculation of the mPFC outgrowing neurites was dependent on the amount of 5-HTT. In the mPFC of 5-HTT-/- pups, we observed clear differences in 5-HT innervation and the identity of a class of projection neurons of the mPFC. In the absence of the 5-HTT, the 5-HT innervation in all subareas of the early postnatal mPFC increased dramatically and the number of Satb2-positive callosal projection neurons was decreased. Together, these results suggest a 5-HTT dependency during early development of these brain areas and in the formation of the raphe-prefrontal network. The tremendous complexity of the 5-HT projection system and its role in several neurodevelopmental disorders highlights the need for further research in this largely

  14. Exaggerated sympathoexcitatory reflexes develop with changes in the rostral ventrolateral medulla in obese Zucker rats.

    Science.gov (United States)

    Huber, Domitila A; Schreihofer, Ann M

    2016-08-01

    Obesity leads to altered autonomic reflexes that reduce stability of mean arterial pressure (MAP). Sympathoinhibitory reflexes such as baroreflexes are impaired, but reflexes that raise MAP appear to be augmented. In obese Zucker rats (OZR) sciatic nerve stimulation evokes larger increases in MAP by unknown mechanisms. We sought to determine the autonomic underpinnings of this enhanced somatic pressor reflex and whether other sympathoexcitatory reflexes are augmented. We also determined whether their final common pathway, glutamatergic activation of the rostral ventrolateral medulla (RVLM), was enhanced in male OZR compared with lean Zucker rats (LZR). Sciatic nerve stimulation or activation of the nasopharyngeal reflex evoked larger rises in splanchnic sympathetic nerve activity (SNA) (79% and 45% larger in OZR, respectively; P reflexes were still exaggerated in OZR (167% and 69% larger, respectively, P reflexes and physiological responses to RVLM activation were comparable. These data suggest that the ability of glutamate to activate the RVLM becomes enhanced in adult OZR and may contribute to the development of exaggerated sympathoexcitatory responses independent of impaired baroreflexes. Copyright © 2016 the American Physiological Society.

  15. Role of the oxytocin receptor expressed in the rostral medullary raphe in thermoregulation during cold conditions

    Directory of Open Access Journals (Sweden)

    Yoshiyuki eKasahara

    2015-11-01

    Full Text Available Recent papers have reported that oxytocin (Oxt and the oxytocin receptor (Oxtr may be involved in the regulation of food intake in mammals. We therefore suspected the Oxt/Oxtr system to be involved in energy homeostasis. In previous studies, we found a tendency toward obesity in Oxtr-deficient mice, as well as impaired thermoregulation when these mice were exposed to cold conditions. In the present study, we observed the expression of Oxtr in the rostral medullary raphe (RMR, the brain region known to control thermogenesis in brown adipose tissue. Through immunohistochemistry, we detected neurons expressing Oxtr and c-Fos in the RMR of mice exposed to cold conditions. Up to 40% of Oxtr-positive neurons in RMR were classified as glutamatergic neurons, as shown by immunostaining using anti-VGLUT3 antibody. In addition, mice with exclusive expression of Oxtr in the RMR were generated by injecting an AAV-Oxtr vector into the RMR region of Oxtr-deficient mice. We confirmed the recovery of thermoregulatory ability in the manipulated mice during exposure to cold conditions. Moreover, mice with RMR-specific expression of Oxtr lost the typical morphological change in brown adipose tissue observed in Oxtr-deficient mice. Additionally, increased expression of the β3-adrenergic receptor gene, Adrb3 was observed in brown adipose tissue. These results are the first to show the critical role of RMR Oxtr expression in thermoregulation during cold conditions.

  16. Effect of moxonidine on putative sympathetic neurons in the rostral ventrolateral medulla of the rat.

    Science.gov (United States)

    Granata, Antonio R

    2004-01-01

    We used an intracellular recording technique in vitro to investigate the effects of moxonidine on neurons in the rostral ventrolateral medulla (RVLM) with electrophysiological properties similar to premotor sympathetic neurons in vivo. These neurons were classified as firing regularly and irregularly, according to previous reports. Moxonidine is a sympathoinhibitory and antihypertensive agent that is thought to be a ligand of alpha(2)-adrenergic receptors and imidazoline type-1 receptors in the RVLM. Moxonidine (2-10 microM) was applied to the perfusate on 4 irregularly firing neurons, and 2 regularly firing neurons. Moxonidine (2 microM) produced only minor depolarization in 2 of these neurons. However, on 4 tested neurons, moxonidine (10 microM) elicited a profound inhibitory effect with hyperpolarization (near -20 mV); these neurons practically ceased firing. These changes were partially reversible. The results would indicate that neurons in the RVLM, recorded in vitro and with similar electrophysiological characteristics to a group of neurons previously identified in vivo in the same bulbar region as barosensitive premotor sympathetic neurons, can be modulated by imidazoline-derivative adrenergic agonists. These results could help to understand the hypotensive effects of moxonidine.

  17. Superoxide Mediates Depressive Effects Induced by Hydrogen Sulfide in Rostral Ventrolateral Medulla of Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Haiyun Yu

    2015-01-01

    Full Text Available Hydrogen sulfide (H2S plays a crucial role in the regulation of blood pressure and oxidative stress. In the present study, we tested the hypothesis that H2S exerts its cardiovascular effects by reducing oxidative stress via inhibition of NADPH oxidase activity in the rostral ventrolateral medulla (RVLM. We examined cell distributions of cystathionine-β-synthase (CBS and effects of H2S on reactive oxygen species (ROS and mean arterial blood pressure (MAP in spontaneously hypertensive rats (SHRs. We found that CBS was expressed in neurons of the RVLM, and the expression was lower in SHRs than in Wistar-Kyoto rats. Microinjection of NaHS (H2S donor, S-adenosyl-l-methionine (SAM, a CBS agonist, or Apocynin (NADPH oxidase inhibitor into the RVLM reduced the ROS level, NADPH oxidase activity, and MAP, whereas microinjection of hydroxylamine hydrochloride (HA, a CBS inhibitor increased MAP. Furthermore, intracerebroventricular infusion of NaHS inhibited phosphorylation of p47phox, a key step of NADPH oxidase activation. Since decreasing ROS level in the RVLM reduces MAP and heart rate and increasing H2S reduces ROS production, we conclude that H2S exerts an antihypertensive effect via suppressing ROS production. H2S, as an antioxidant, may be a potential target for cardiovascular diseases.

  18. The rostral migratory stream plays a key role in intranasal delivery of drugs into the CNS.

    Directory of Open Access Journals (Sweden)

    Robert A Scranton

    Full Text Available BACKGROUND: The blood brain barrier (BBB is impermeable to most drugs, impeding the establishment of novel neuroprotective therapies and strategies for many neurological diseases. Intranasal administration offers an alternative path for efficient drug delivery into the CNS. So far, the anatomical structures discussed to be involved in the transport of intranasally administered drugs into the CNS include the trigeminal nerve, olfactory nerve and the rostral migratory stream (RMS, but the relative contributions are debated. METHODS AND FINDINGS: In the present study we demonstrate that surgical transection, and the resulting structural disruption of the RMS, in mice effectively obstructs the uptake of intranasally administered radioligands into the CNS. Furthermore, using a fluorescent cell tracer, we demonstrate that intranasal administration in mice allows agents to be distributed throughout the entire brain, including olfactory bulb, hippocampus, cortex and cerebellum. CONCLUSIONS: This study provides evidence of the vital role the RMS has in the CNS delivery of intranasally administered agents. The identification of the RMS as the major access path for intranasally administered drugs into the CNS may contribute to the development of treatments that are tailored for efficient transport within this structure. Research into the RMS needs to continue to elucidate its limitations, capabilities, mechanisms of transport and potential hazards before we are able to advance this technique into human research.

  19. The role of rostral Brodmann area 6 in mental-operation tasks: an integrative neuroimaging approach.

    Science.gov (United States)

    Hanakawa, Takashi; Honda, Manabu; Sawamoto, Nobukatsu; Okada, Tomohisa; Yonekura, Yoshiharu; Fukuyama, Hidena; Shibasaki, Hiroshi

    2002-11-01

    Recent evidence indicates that classical 'motor' areas may also have cognitive functions. We performed three neuroimaging experiments to investigate the functional neuroanatomy underlying three types of nonmotor mental-operation tasks: numerical, verbal, and spatial. (i) Positron emission tomography showed that parts of the posterior frontal cortex, which are consistent with the pre-supplementary motor area (pre-SMA) and the rostral part of the dorsolateral premotor cortex (PMdr), were active during all three tasks. We also observed activity in the posterior parietal cortex and cerebellar hemispheres during all three tasks. Electrophysiological monitoring confirmed that there were no skeletomotor, oculomotor or articulatory movements during task performance. (ii) Functional magnetic resonance imaging (fMRI) showed that PMdr activity during the mental-operation tasks was localized in the depths of the superior precentral sulcus, which substantially overlapped the region active during complex finger movements and was located dorsomedial to the presumptive frontal eye fields. (iii) Single-trial fMRI showed a transient increase in activity time-locked to the performance of mental operations in the pre-SMA and PMdr. The results of the present study suggest that the PMdr is important in the rule-based association of symbolic cues and responses in both motor and nonmotor behaviors.

  20. Differentiation of papillae and rostral sensory neurons in the larva of the ascidian Botryllus schlosseri (Tunicata).

    Science.gov (United States)

    Caicci, Federico; Zaniolo, Giovanna; Burighel, Paolo; Degasperi, Valentina; Gasparini, Fabio; Manni, Lucia

    2010-02-15

    During the metamorphosis of tunicate ascidians, the swimming larva uses its three anterior papillae to detect the substrate for settlement, reabsorbs its chordate-like tail, and becomes a sessile oozooid. In view of the crucial role played by the anterior structures and their nerve relations, we applied electron microscopy and immunocytochemistry to study the larva of the colonial ascidian Botryllus schlosseri, following differentiation of the anterior epidermis during late embryogenesis, the larval stage, and the onset of metamorphosis. Rudiments of the papillae appear in the early tail-bud stage as ectodermic protrusions, the apexes of which differentiate into central and peripheral bipolar neurons. Axons fasciculate into two nerves direct to the brain. Distally, the long, rod-like dendritic terminations extend during the larval stage, becoming exposed to sea water. After the larva selects and adheres to the substrate, these neurons retract and regress. Adjacent to the papillae, other scattered neurons insinuate dendrites into the tunic and form the net of rostral trunk epidermal neurons (RTENs) which fasciculate together with the papillary neurons. Our data indicate that the papillae are simple and coniform, the papillary neurons are mechanoreceptors, and the RTENs are chemoreceptors. The interpapillary epidermal area, by means of an apocrine secretion, provides sticky material for temporary adhesion of the larva to the substrate.

  1. Medial prefrontal depressor response: involvement of the rostral and caudal ventrolateral medulla in the rat.

    Science.gov (United States)

    Owens, N C; Verberne, A J

    2000-01-14

    The importance of neurones of the caudal and rostral ventrolateral medulla (CVLM and RVLM, respectively) in mediation of the medial prefrontal cortex depressor response was studied in halothane-anaesthetised rats. Blockade of GABA(A) receptors in the RVLM produced by microinjection of bicuculline (50 nl, 2 mM, n = 6) resulted in reversal of the depressor (-9.5 +/- 1.2 mm Hg) and lumbar sympathetic (-6.5 +/- 5.7 units) responses to pressor (+7.8 +/- 3.5 mm Hg) and sympathoexcitatory (+19.3 +/- 12.5 units) responses and simultaneous blockade of baroreceptor reflex-mediated sympathoinhibition. Baroreflex blockade was reflected by a significant reduction in the gain (slope of the blood pressure vs. lumbar sympathetic nerve discharge regression line) of the reflex. Microinjection of the excitatory amino acid antagonist kynurenic acid (100 nl, 50 mM, n = 6) into the CVLM blocked the baroreflex and significantly reduced the depressor (-9.6 +/- 0.4 to -6.9 +/- 0.6 mm Hg) and lumbar sympathetic (-4.0 +/- 2.1 to 2.9 +/- 1.9 units) responses to medial prefrontal cortex stimulation. These results support the hypothesis that the medial prefrontal cortex depressor response is mediated by a pathway which converges at the level of the RVLM and which is only partly dependent on an excitatory input to caudal ventrolateral medullary neurones.

  2. The generation of oligodendroglial cells is preserved in the rostral migratory stream during aging

    Directory of Open Access Journals (Sweden)

    Vivian eCapilla-Gonzalez

    2013-09-01

    Full Text Available The subventricular zone (SVZ is the largest source of newly generated cells in the adult mammalian brain. SVZ-derived neuroblasts migrate via the rostral migratory stream (RMS to the olfactory bulb (OB, where they differentiate into mature neurons. Additionally, a small proportion of SVZ-derived cells contribute to the generation of myelinating oligodendrocytes. The production of new cells in the SVZ decreases during aging, affecting the incorporation of new neurons into the OB. However, the age-related changes that occur across the RMS are not fully understood. In this study we evaluate how aging affects the cellular organization of migrating neuroblast chains, the proliferation, and the fate of the newly generated cells in the SVZ-OB system. By using electron microscopy and immunostaining, we found that the RMS path becomes discontinuous and its cytoarchitecture is disorganized in aged mice (24-month-old mice. Subsequently, OB neurogenesis was impaired in the aged brain while the production of oligodendrocytes was not compromised. These findings provide new insight into oligodendrocyte preservation throughout life. Further exploration of this matter could help the development of new strategies to prevent neurological disorders associated with senescence.

  3. SPINAL CORD MECHANISMS MEDIATING BEHAVIORAL HYPERALGESIA INDUCED BY NEUROKININ-1 TACHYKININ RECEPTOR ACTIVATION IN THE ROSTRAL VENTROMEDIAL MEDULLA

    OpenAIRE

    Lagraize, S. C.; Guo, W; Yang, K.; Wei, F.; Ren, K; Dubner, R.

    2010-01-01

    Hyperalgesia in animal injury models is linked to activation of descending raphespinal modulatory circuits originating in the rostral ventromedial medulla (RVM). A neurokinin-1 (NK-1) receptor antagonist microinjected into the RVM before or after inflammation produced by complete Freund’s adjuvant (CFA) resulted in an attenuation of thermal hyperalgesia. A transient (acute) or a continuous infusion of Substance P (SP) microinjected into the RVM of non-inflamed animals led to similar pain hype...

  4. Clarifying the role of the rostral dmPFC/dACC in fear/anxiety: learning, appraisal or expression?

    Directory of Open Access Journals (Sweden)

    Simon Maier

    Full Text Available Recent studies have begun to carve out a specific role for the rostral part of the dorsal medial prefrontal cortex (dmPFC and adjacent dorsal anterior cingulate cortex (dACC in fear/anxiety. Within a novel general framework of dorsal mPFC/ACC areas subserving the appraisal of threat and concomitant expression of fear responses and ventral mPFC/ACC areas subserving fear regulation, the rostral dmPFC/dACC has been proposed to specifically mediate the conscious, negative appraisal of threat situations including, as an extreme variant, catastrophizing. An alternative explanation that has not been conclusively ruled out yet is that the area is involved in fear learning. We tested two different fear expression paradigms in separate fMRI studies (study 1: instructed fear, study 2: testing of Pavlovian conditioned fear with independent groups of healthy adult subjects. In both paradigms the absence of reinforcement precluded conditioning. We demonstrate significant BOLD activation of an identical rostral dmPFC/dACC area. In the Pavlovian paradigm (study 2, the area only activated robustly once prior conditioning had finished. Thus, our data argue against a role of the area in fear learning. We further replicate a repeated observation of a dissociation between peripheral-physiological fear responding and rostral dmPFC/dACC activation, strongly suggesting the area does not directly generate fear responses but rather contributes to appraisal processes. Although we succeeded in preventing extinction of conditioned responding in either paradigm, the data do not allow us to definitively exclude an involvement of the area in fear extinction learning. We discuss the broader implications of this finding for our understanding of mPFC/ACC function in fear and in negative emotion more generally.

  5. Neural Response Properties of Primary, Rostral, and Rostrotemporal Core Fields in the Auditory Cortex of Marmoset Monkeys

    OpenAIRE

    Bendor, Daniel; WANG, Xiaoqin

    2008-01-01

    The core region of primate auditory cortex contains a primary and two primary-like fields (AI, primary auditory cortex; R, rostral field; RT, rostrotemporal field). Although it is reasonable to assume that multiple core fields provide an advantage for auditory processing over a single primary field, the differential roles these fields play and whether they form a functional pathway collectively such as for the processing of spectral or temporal information are unknown. In this report we compa...

  6. Can chronic remote cortical hypoperfusion induced by thalamic infarction cause damage of tracts passing through those hypoperfused regions?

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    Eloi eMagnin

    2013-10-01

    Full Text Available We report the case of a woman presenting with changes on cerebral imaging a year and a half after a bi-thalamic (predominantly left-sided infarction including lateral and medial thalamic nuclei. Lateral geniculate body and pulvinar were not damaged. Hypoperfusion was observed in left cortical and basal structures. White matter FLAIR hyperintense lesions occurred in the left hemisphere and the occipital region one year and half after stroke. Medial and lateral thalamic nuclei are not highly connected to the occipital cortex. Therefore, in addition to Wallerian degeneration after thalamic stroke, we hypothesize that the chronic left temporal hypoperfusion induced by diaschisis can lead to a lateralized chronic hypoxic damage of the occipital fiber tract (optic radiation that passes through the temporal lobe.

  7. Dynamics of epileptic activity in a peculiar case of childhood absence epilepsy and correlation with thalamic levels of GABA

    Directory of Open Access Journals (Sweden)

    Alberto Leal

    2016-01-01

    Significance: In a clinical case of CAE with EEG and fMRI-BOLD manifestations restricted to one hemisphere, we found an associated increase in thalamic GABA concentration consistent with a role for this abnormality in human CAE.

  8. Feasibility of diffusion tractography for the reconstruction of intra-thalamic and cerebello-thalamic targets for functional neurosurgery: a multi-vendor pilot study in four subjects

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    Andras Jakab

    2016-07-01

    Full Text Available Functional stereotactic neurosurgery by means of deep brain stimulation or ablation provides an effective treatment for movement disorders, but the outcome of surgical interventions depends on the accuracy by which the target structures are reached. The purpose of this pilot study was to evaluate the feasibility of diffusion tensor imaging (DTI based probabilistic tractography of deep brain structures that are commonly used for pre- and perioperative targeting for functional neurosurgery. Three targets were reconstructed based on their significance as intervention sites or as a no-go area to avoid adverse side effects: the connections propagating from the thalamus to (1 primary and supplementary motor areas, (2 to somatosensory areas and the cerebello-thalamic tract. We evaluated the overlap of the reconstructed connectivity based targets with corresponding atlas based data, and tested the inter-subject and inter-scanner variability by acquiring repeated DTI from four volunteers, and on three MRI scanners with similar sequence parameters.Compared to a 3D histological atlas of the human thalamus, moderate overlaps of 35-50% were measured between connectivity- and atlas based volumes, while the minimal distance between the centerpoints of atlas and connectivity targets was 2.5 mm. The variability caused by the MRI scanner was similar to the inter-subject variability, except for connections with the postcentral gyrus where it was higher. While cerebello-thalamic tractography resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners. DTI can be applied in the clinical, preoperative setting to reconstruct the cerebello-thalamic tract and to localize subdivisions within the lateral thalamus. In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv nucleus and the ventral-posterolateral (VPL nucleus. Limitations

  9. Thalamic structures and associated cognitive functions: Relations with age and aging

    Science.gov (United States)

    Fama, Rosemary; Sullivan, Edith V.

    2015-01-01

    The thalamus, with its cortical, subcortical, and cerebellar connections, is a critical node in networks supporting cognitive functions known to decline in normal aging, including component processes of memory and executive functions of attention and information processing. The macrostructure, microstructure, and neural connectivity of the thalamus changes across the adult lifespan. Structural and functional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have demonstrated, regional thalamic volume shrinkage and microstructural degradation, with anterior regions generally more compromised than posterior regions. The integrity of selective thalamic nuclei and projections decline with advancing age, particularly those in thalamofrontal, thalamoparietal, and thalamolimbic networks. This review presents studies that assess the relations between age and aging and the structure, function, and connectivity of the thalamus and associated neural networks and focuses on their relations with processes of attention, speed of information processing, and working and episodic memory. PMID:25862940

  10. Stereological analysis of the mediodorsal thalamic nucleus in schizophrenia: volume, neuron number, and cell types

    DEFF Research Database (Denmark)

    Dorph-Petersen, Karl-Anton; Pierri, Joseph N; Sun, Zhuoxin

    2004-01-01

    The mediodorsal thalamic nucleus (MD) is the principal relay nucleus for the prefrontal cortex, a brain region thought to be dysfunctional in schizophrenia. Several, but not all, postmortem studies of the MD in schizophrenia have reported decreased volume and total neuronal number. However......, it is not clear whether the findings are specific for schizophrenia nor is it known which subtypes of thalamic neurons are affected. We studied the left MD in 11 subjects with schizophrenia, 9 control subjects, and 12 subjects with mood disorders. Based on morphological criteria, we divided the neurons into two...... subclasses, presumably corresponding to projection neurons and local circuit neurons. We estimated MD volume and the neuron number of each subclass using methods based on modern unbiased stereological principles. We also estimated the somal volumes of each subclass using a robust, but biased, approach...

  11. The olfactory thalamus: unanswered questions about the role of the mediodorsal thalamic nucleus in olfaction

    Directory of Open Access Journals (Sweden)

    Emmanuelle eCourtiol

    2015-09-01

    Full Text Available The mediodorsal thalamic nucleus (MDT is a higher order thalamic nucleus and its role in cognition is increasingly well established. Interestingly, components of the MDT also have a somewhat unique sensory function as they link primary olfactory cortex to orbitofrontal associative cortex. In fact, anatomical evidence firmly demonstrates that the MDT receives direct input from primary olfactory areas including the piriform cortex and has dense reciprocal connections with the orbitofrontal cortex. The functions of this olfactory pathway have been poorly explored but lesion, imaging, and electrophysiological studies suggest that these connections may be involved in olfactory processing including odor perception, discrimination, learning, and attention. However, many important questions regarding the MDT and olfaction remain unanswered. Our goal here is not only to briefly review the existing literature but also to highlight some of the remaining questions that need to be answered to better define the role(s of the MDT in olfactory processing.

  12. A change in thalamic function in patients of chronic pain. A functional brain study with SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Mitsuru; Doi, Nagafumi; Isse, Kunihiro [Tokyo Metropolitan Ebara General Hospital (Japan)] [and others

    1999-02-01

    The cerebral blood flow was measured by SPECT using {sup 99m}Tc-ECD as tracer in order to make chronic pain clear physiopathologically. Subjects were 7 cases of central pain (4 cases of thalamus and 3 cases of putamen) and 3 cases of postherpetic neuralgia, who were treated by ECT and had good response in the Tokyo Metropolitan Ebara General Hospital. Reduction of cerebral blood flow in the thalamus was recognized at opposite side of pain (the side with cerebrovascular diseases) in central pain; at both sides in postherpetic neuralgia. In both groups, pain and allodynia disappeared by ECT, and the thalamic cerebral blood flow at opposite side became to be normal. These results suggest that chronic pain was related to decrease thalamic activity at opposite side physiopathologically. (K.H.)

  13. The olfactory thalamus: unanswered questions about the role of the mediodorsal thalamic nucleus in olfaction.

    Science.gov (United States)

    Courtiol, Emmanuelle; Wilson, Donald A

    2015-01-01

    The mediodorsal thalamic nucleus (MDT) is a higher order thalamic nucleus and its role in cognition is increasingly well established. Interestingly, components of the MDT also have a somewhat unique sensory function as they link primary olfactory cortex to orbitofrontal associative cortex. In fact, anatomical evidence firmly demonstrates that the MDT receives direct input from primary olfactory areas including the piriform cortex and has dense reciprocal connections with the orbitofrontal cortex. The functions of this olfactory pathway have been poorly explored but lesion, imaging, and electrophysiological studies suggest that these connections may be involved in olfactory processing including odor perception, discrimination, learning, and attention. However, many important questions regarding the MDT and olfaction remain unanswered. Our goal here is not only to briefly review the existing literature but also to highlight some of the remaining questions that need to be answered to better define the role(s) of the MDT in olfactory processing.

  14. Memory Profiles after Unilateral Paramedian Thalamic Stroke Infarction: A Comparative Study

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    Antonio Carota

    2015-01-01

    Full Text Available We performed extensive neuropsychological assessment of two male patients (matched for age and educational level with similar (localization and size unilateral paramedian ischemic thalamic lesions (AB on the left and SD on the right. Both patients showed severe memory impairments as well as other cognitive deficits. In comparison to SD, AB showed severe impairment of executive functions and a more severe deficit of episodic/anterograde memory, especially in the verbal modality. The findings of this single case study suggest the possibility that the profile and severity of the executive dysfunction are determinant for the memory deficits and depend on from the side of the lesion. In addition to a material-side-specific (verbal versus visual deficit hypothesis, the differential diencephalo-prefrontal contributions in mnestic-processing, in case of paramedian thalamic stroke, might also be explained in terms of their stage-specificity (encoding versus retrieval.

  15. Hypofractionated Stereotactic Radiosurgery in a Large Bilateral Thalamic and Basal Ganglia Arteriovenous Malformation

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    Janet Lee

    2013-01-01

    Full Text Available Purpose. Arteriovenous malformations (AVMs in the basal ganglia and thalamus have a more aggressive natural history with a higher morbidity and mortality than AVMs in other locations. Optimal treatment—complete obliteration without new neurological deficits—is often challenging. We present a patient with a large bilateral basal ganglia and thalamic AVM successfully treated with hypofractionated stereotactic radiosurgery (HFSRS with intensity modulated radiotherapy (IMRT. Methods. The patient was treated with hypofractionated stereotactic radiosurgery to 30 Gy at margin in 5 fractions of 9 static fields with a minimultileaf collimator and intensity modulated radiotherapy. Results. At 10 months following treatment, digital subtraction angiography showed complete obliteration of the AVM. Conclusions. Large bilateral thalamic and basal ganglia AVMs can be successfully treated with complete obliteration by HFSRS with IMRT with relatively limited toxicity. Appropriate caution is recommended.

  16. Leptin into the rostral ventral lateral medulla (RVLM augments renal sympathetic nerve activity and blood pressure

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    Maria J Barnes

    2014-08-01

    Full Text Available Leptin is a hormone released from adipose tissue. While this hormone normally acts to reduce feeding behavior and increase energy expenditure, in obesity, resistance to these effects occurs even though the hormone is released in large amounts. Although leptin no longer works to suppress feeding in the obese, leptin retains its potent effects on other autonomic functions such as blood pressure regulation. Leptin has been associated with hypertension and increased sympathetic autonomic activity. Therefore, leptin is emerging as a major contributor to the hypertensive state observed in obesity. Sympathetic control of blood pressure is maintained principally by autonomic reflex control circuits in the caudal brainstem. The rostral ventral-lateral medulla (RVLM is the primary regulator of the sympathetic nervous system, sending excitatory fibers to sympathetic preganglionic neurons to regulate sympathetic control over resistance vessels and blood pressure. Previous studies from our laboratory have shown that neurons in the ventral lateral medulla express leptin receptors (ObRb. Our present study using pseudo-rabies multi-synaptic retrograde tract tracing and immunohistochemical methods revealed that neurons within the RVLM that send sympathetic projections to the kidney express leptin receptors. Acute microinjection of leptin (1 and 3µg; 40nL into the RVLM evoked a significant increase in Mean Arterial Pressure (MAP and renal sympathetic nerve activity (RSNA. When the 3µg dose of leptin was preceded with a leptin antagonist, (SLAN-4; 1ng, it attenuated the cardiovascular response of leptin. Taken together, these data suggest that leptin’s actions within the RVLM may influence blood pressure and renal sympathetic nerve activity.

  17. EGF-induced expansion of migratory cells in the rostral migratory stream.

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    Olle R Lindberg

    Full Text Available The presence of neural stem cells in the adult brain is currently widely accepted and efforts are made to harness the regenerative potential of these cells. The dentate gyrus of the hippocampal formation, and the subventricular zone (SVZ of the anterior lateral ventricles, are considered the main loci of adult neurogenesis. The rostral migratory stream (RMS is the structure funneling SVZ progenitor cells through the forebrain to their final destination in the olfactory bulb. Moreover, extensive proliferation occurs in the RMS. Some evidence suggest the presence of stem cells in the RMS, but these cells are few and possibly of limited differentiation potential. We have recently demonstrated the specific expression of the cytoskeleton linker protein radixin in neuroblasts in the RMS and in oligodendrocyte progenitors throughout the brain. These cell populations are greatly altered after intracerebroventricular infusion of epidermal growth factor (EGF. In the current study we investigate the effect of EGF infusion on the rat RMS. We describe a specific increase of radixin(+/Olig2(+ cells in the RMS. Negative for NG2 and CNPase, these radixin(+/Olig2(+ cells are distinct from typical oligodendrocyte progenitors. The expanded Olig2(+ population responds rapidly to EGF and proliferates after only 24 hours along the entire RMS, suggesting local activation by EGF throughout the RMS rather than migration from the SVZ. In addition, the radixin(+/Olig2(+ progenitors assemble in chains in vivo and migrate in chains in explant cultures, suggesting that they possess migratory properties within the RMS. In summary, these results provide insight into the adaptive capacity of the RMS and point to an additional stem cell source for future brain repair strategies.

  18. Increased sympathetic nerve activity correlates with neurovascular compression at the rostral ventrolateral medulla.

    Science.gov (United States)

    Sendeski, Mauricio M; Consolim-Colombo, Fernanda Marciano; Leite, Claudia Costa; Rubira, Marcelo Custódio; Lessa, Patricia; Krieger, Eduardo Moacyr

    2006-05-01

    We used microneurography to measure muscle sympathetic nerve activity (MSNA) in 25 hypertensive subjects and correlated these results with the presence or absence of signs of neurovascular compression (NVC) at the rostral ventrolateral (RVL) medulla on MRI. Subjects were divided into 3 groups based on MRI findings: NVC-, no MRI evidence of NVC (N=9); NVC+contact, image showing artery in contact but not compressing the RVL medulla (N=8); and NVC+compression, image showing arterial compression of the RVL medulla (N=8). The MSNA measurements were performed at rest, after a hypothermic stimulus, and during isometric exercise. The MSNA during rest in the NVC+compression group was significantly higher than that in the NVC+contact and NVC- groups (30.4+/-3.4 versus 17.5+/-1.1 and 21.4+/-3.2 spikes per minute, respectively). However, the blood pressure in the NVC+compression group was slightly but not significantly higher than that in the other 2 groups (183+/-7/115+/-8, 174+/-6/108+/-7, and 171+/-5/110+/-5 mm Hg, respectively). The increases in MSNA, blood pressure, and heart rate during the cold pressor and isometric exercise tests were similar. Our results show that, although resting MSNA is elevated in patients with true NVC of the RVL medulla, patients without NVC or with arterial contact but not overt compression of the RVL medulla have similar MSNA. These findings are important for identifying, among hypertensive patients with NVC, individuals who may have associated physiological repercussions, such as increased sympathetic activity.

  19. Activation of rostral ventromedial medulla neurons by noxious stimulation of cutaneous and deep craniofacial tissues.

    Science.gov (United States)

    Khasabov, Sergey G; Malecha, Patrick; Noack, Joseph; Tabakov, Janneta; Okamoto, Keiichiro; Bereiter, David A; Simone, Donald A

    2015-01-01

    The rostral ventromedial medulla (RVM) projects to the medullary and spinal dorsal horns and is a major source of descending modulation of nociceptive transmission. Traditionally, neurons in the RVM are classified functionally as on, off, and neutral cells on the basis of responses to noxious cutaneous stimulation of the tail or hind paw. On cells facilitate nociceptive transmission, off cells are inhibitory, whereas neutral cells are unresponsive to noxious stimuli and their role in pain modulation is unclear. Classification of RVM neurons with respect to stimulation of craniofacial tissues is not well defined. In isoflurane-anesthetized male rats, RVM neurons first were classified as on (25.5%), off (25.5%), or neutral (49%) cells by noxious pinch applied to the hind paw. Pinching the skin overlying the temporomandibular joint (TMJ) altered the proportions of on (39.2%), off (42.2%), and neutral (19.6%) cells. To assess the response of RVM cells to specialized craniofacial inputs, adenosine triphosphate (ATP; 0.01-1 mM) was injected into the TMJ and capsaicin (0.1%) was applied to the ocular surface. TMJ and ocular surface stimulation also resulted in a reduced proportion of neutral cells compared with hind paw pinch. Dose-effect analyses revealed that on and off cells encoded the intra-TMJ concentration of ATP. These results suggest that somatotopy plays a significant role in the functional classification of RVM cells and support the notion that neutral cells likely are subgroups of on and off cells. It is suggested that a portion of RVM neurons serve different functions in modulating craniofacial and spinal pain conditions.

  20. AT1 receptor in rostral ventrolateral medulla mediating blunted baroreceptor reflex in spontaneously hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    Xin-ya GAO; Feng ZHANG; Ying HAN; Han-jun WANG; Ying ZHANG; Rui GUO; Guo-qing ZHU

    2004-01-01

    AIM: To determine the role of AT1 receptor in the rostral ventrolateral medulla (RVLM) in mediating the blunted baroreceptor reflex in spontaneously hypertensive rats (SHR). METHODS: Intravenous injections of graded doses of phenylephrine (1, 5, 10, 20, and 40 μg/kg) increased the blood pressure to elicit the baroreceptor reflex in both SHR and normotensive Wistar rats anesthetized with urethane. The baroreceptor reflex sensitivity (BRS) was determined before and after microinjection of Ang Ⅱ, losartan, or AT1 receptor antisense oligodeoxynucleotides into the RVLM. AT1 receptor protein level in the RVLM was measured by Western blotting. RESULTS: The BRS was significantly decreased in SHR compared with normal rats. Bilateral microinjection of AT1 receptor antagonist losartan (250 nmol/h) into the RVLM partly reversed the blunted BRS in SHR, but had no significant effect on the BRS in normal rats. Ang Ⅱ (1.5 nmol/h) significantly inhibited the BRS in normal rats, which was completely abolished by pretreatment with losartan. However, no significant change in the BRS was observed after microinjection of Ang Ⅱ into the RVLM in SHR. Bilateral microinjection of AT1 receptor antisense oligodeoxynucleotides(ASODN) into the RVLM partially recovered the blunted BRS in SHR after 3 h, but no significant change in the BRS was observed in normal rats. The AT1 receptor protein level significantly decreased after administration of ASODN.CONCLUSION: Blockage of AT1 receptor or inhibition of AT1 receptor protein synthesis in the RVLM enhanced the BRS in SHR, suggesting that the enhanced activities of AT1 receptor in the RVLM contribute to the blunted BRS in SHR.

  1. Trigeminal-Rostral Ventromedial Medulla circuitry is involved in orofacial hyperalgesia contralateral to tissue injury

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    Chai Bryan

    2012-10-01

    Full Text Available Abstract Background Our previous studies have shown that complete Freund’s adjuvant (CFA-induced masseter inflammation and microinjection of the pro-inflammatory cytokine interleukin-1β (IL-1β into the subnucleus interpolaris/subnucleus caudalis transition zone of the spinal trigeminal nucleus (Vi/Vc can induce contralateral orofacial hyperalgesia in rat models. We have also shown that contralateral hyperalgesia is attenuated with a lesion of the rostral ventromedial medulla (RVM, a critical site of descending pain modulation. Here we investigated the involvement of the RVM-Vi/Vc circuitry in mediating contralateral orofacial hyperalgesia after an injection of CFA into the masseter muscle. Results Microinjection of the IL-1 receptor antagonist (5 nmol, n=6 into the ipsilateral Vi/Vc attenuated the CFA-induced contralateral hyperalgesia but not the ipsilateral hyperalgesia. Intra-RVM post-treatment injection of the NK1 receptor antagonists, RP67580 (0.5-11.4 nmol and L-733,060 (0.5-11.4 nmol, attenuated CFA-induced bilateral hyperalgesia and IL-1β induced bilateral hyperalgesia. Serotonin depletion in RVM neurons prior to intra-masseter CFA injection prevented the development of contralateral hyperalgesia 1–3 days after CFA injection. Inhibition of 5-HT3 receptors in the contralateral Vi/Vc with direct microinjection of the select 5-HT3 receptor antagonist, Y-25130 (2.6-12.9 nmol, attenuated CFA-induced contralateral hyperalgesia. Lesions to the ipsilateral Vc prevented the development of ipsilateral hyperalgesia but did not prevent the development of contralateral hyperalgesia. Conclusions These results suggest that the development of CFA-induced contralateral orofacial hyperalgesia is mediated through descending facilitatory mechanisms of the RVM-Vi/Vc circuitry.

  2. Selective optogenetic activation of rostral ventrolateral medullary catecholaminergic neurons produces cardiorespiratory stimulation in conscious mice.

    Science.gov (United States)

    Abbott, Stephen B G; DePuy, Seth D; Nguyen, Thanh; Coates, Melissa B; Stornetta, Ruth L; Guyenet, Patrice G

    2013-02-13

    Activation of rostral ventrolateral medullary catecholaminergic (RVLM-CA) neurons e.g., by hypoxia is thought to increase sympathetic outflow thereby raising blood pressure (BP). Here we test whether these neurons also regulate breathing and cardiovascular variables other than BP. Selective expression of ChR2-mCherry by RVLM-CA neurons was achieved by injecting Cre-dependent vector AAV2-EF1α-DIO-ChR2-mCherry unilaterally into the brainstem of dopamine-β-hydroxylase(Cre/0) mice. Photostimulation of RVLM-CA neurons increased breathing in anesthetized and conscious mice. In conscious mice, photostimulation primarily increased breathing frequency and this effect was fully occluded by hypoxia (10% O(2)). In contrast, the effects of photostimulation were largely unaffected by hypercapnia (3 and 6% CO(2)). The associated cardiovascular effects were complex (slight bradycardia and hypotension) and, using selective autonomic blockers, could be explained by coactivation of the sympathetic and cardiovagal outflows. ChR2-positive RVLM-CA neurons expressed VGLUT2 and their projections were mapped. Their complex cardiorespiratory effects are presumably mediated by their extensive projections to supraspinal sites such as the ventrolateral medulla, the dorsal vagal complex, the dorsolateral pons, and selected hypothalamic nuclei (dorsomedial, lateral, and paraventricular nuclei). In sum, selective optogenetic activation of RVLM-CA neurons in conscious mice revealed two important novel functions of these neurons, namely breathing stimulation and cardiovagal outflow control, effects that are attenuated or absent under anesthesia and are presumably mediated by the numerous supraspinal projections of these neurons. The results also suggest that RVLM-CA neurons may underlie some of the acute respiratory response elicited by carotid body stimulation but contribute little to the central respiratory chemoreflex.

  3. AT1 receptor in rostral ventrolateral medulla mediating blunted baroreceptor reflex in spontaneously hypertensive rats

    Institute of Scientific and Technical Information of China (English)

    Xin-yaGAO; FengZHANG; YingHAN; Han-junWANG; YingZHANG; RuiGUO; Guo-qingZHU

    2004-01-01

    AIM: To determine the role of AT1 receptor in the rostral ventrolateral medulla (RVLM) in mediating the blunted baroreceptor reflex in spontaneously hypertensive rats (SHR). METHODS: Intravenous injections of graded doses of phenylephrine (1, 5, 10, 20, and 40μg/kg) increased the blood pressure to elicit the baroreceptor reflex in both SHR and normotensive Wistar rats anesthetized with urethane. The baroreceptor reflex sensitivity (BRS) was determined before and after microinjection of Ang II, losartan, or AT1 receptor antisense oligodeoxynucleotides into the RVLM. AT1 receptor protein level in the RVLM was measured by Western blotting. RESULTS: The BRS was significantly decreased in SHR compared with normal rats. Bilateral microinjection of AT~ receptor antagonist losartan (250 nmol/h) into the RVLM partly reversed the blunted BRS in SHR, but had no significant effect on the BRS in normal rats. Ang II (1.5 nmol/h) significantly inhibited the BRS in normal rats, which was completely abolished by pretreatment with losartan. However, no significant change in the BRS was observed after microinjection of Ang Ⅱ into the RVLM in SHR. Bilateral microinjection of AT1 receptor antisense oligodeoxynucleotides (ASODN) into the RVLM partially recovered the blunted BRS in SHR after 3 h, but no significant change in the BRS was observed in normal rats. The AT1 receptor protein level significantly decreased after administration of ASODN. CONCLUSION: Blockage of AT1 receptor or inhibition of AT1 receptor protein synthesis in the RVLM enhanced the BRS in SHR, suggesting that the enhanced activities of AT1 receptor in the RVLM contribute to the blunted BRS in SHR.

  4. Leptin Responsive and GABAergic Projections to the Rostral Preoptic Area in Mice.

    Science.gov (United States)

    Zuure, W A; Quennell, J H; Anderson, G M

    2016-03-01

    The adipocyte-derived hormone leptin plays a critical role in the control of reproduction via signalling in hypothalamic neurones. The drivers of the hypothalamic-pituitary-gonadal axis, the gonadotrophin-releasing hormone (GnRH) neurones, do not have the receptors for leptin. Therefore, intermediate leptin responsive neurones must provide leptin-to-GnRH signalling. We investigated the populations of leptin responsive neurones that provide input to the rostral preoptic area (rPOA) where GnRH cell bodies reside. Fluorescent retrograde tracer beads (RetroBeads; Lumafluor Inc., Naples, FL, USA) were injected into the rPOA of transgenic leptin receptor enhanced green fluorescent protein (Lepr-eGFP) reporter mice. Uptake of the RetroBeads by Lepr-eGFP neurones was assessed throughout the hypothalamus. RetroBead uptake was most evident in the medial arcuate nucleus (ARC), the dorsomedial nucleus (DMN) and the ventral premammillary nucleus (PMV) of the hypothalamus. The uptake of RetroBeads specifically by Lepr-eGFP neurones was highest in the medial ARC (18% of tracer-labelled neurones Lepr-eGFP-positive). Because neurones that are both leptin responsive and GABAergic play a critical role in the regulation of fertility by leptin, we next focussed on the location of these populations. To address whether GABAergic neurones in leptin-responsive hypothalamic regions project to the rPOA, the experiment was repeated in GABA neurone reporter mice (Vgat-tdTomato). Between 10% and 45% of RetroBead-labelled neurones in the ARC were GABAergic, whereas uptake of tracer by GABAergic neurones in the DMN and PMV was very low (leptin responsive and GABAergic neurones from the ARC project to the region of the GnRH cell bodies. Our findings suggest that LEPR-expressing GABA neurones from the ARC may be mediators of leptin-to-GnRH signalling.

  5. Caudal topographic nucleus isthmi and the rostral nontopographic nucleus isthmi in the turtle, Pseudemys scripta.

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    Sereno, M I; Ulinski, P S

    1987-07-15

    Isthmotectal projections in turtles were examined by making serial section reconstructions of axonal and dendritic arborizations that were anterogradely or retrogradely filled with HRP. Two prominent tectal-recipient isthmic nuclei--the caudal magnocellular nucleus isthmi (Imc) and the rostral magnocellular nucleus isthmi (Imr)--exhibited strikingly different patterns of organization. Imc cells have flattened, bipolar dendritic fields that cover a few percent of the area of the cell plate constituting the nucleus and they project topographically to the ipsilateral tectum without local axon branches. The topography was examined explicitly at the single-cell level by using cases with two injections at widely separated tectal loci. Each Imc axon terminates as a compact swarm of several thousand boutons placed mainly in the upper central gray and superficial gray layers. One Imc terminal spans less that 1% of the tectal surface. Imr cells, by contrast, have large, sparsely branched dendritic fields overlapped by local axon collaterals while distally, their axons nontopographically innervate not only the deeper layers of the ipsilateral tectum but also ipsilateral Imc. Imr receives a nontopographic tectal input that contrasts with the topographic tectal input to Imc. Previous work on nucleus isthmi emphasized the role of the contralateral isthmotectal projection (which originates from a third isthmic nucleus in turtles) in mediating binocular interactions in the tectum. The present results on the two different but overlapping ipsilateral tecto-isthmo-tectal circuits set up by Imc and Imr are discussed in the light of physiological evidence for selective attention effects and local-global interactions in the tectum.

  6. Effect of Spinal Manipulation Thrust Magnitude on Trunk Mechanical Thresholds of Lateral Thalamic Neurons

    Science.gov (United States)

    Reed, William R.; Pickar, Joel G.; Sozio, Randall S.; Long, Cynthia R.

    2014-01-01

    Objectives High velocity low amplitude spinal manipulation (HVLA-SM), as performed by manual therapists (eg, doctors of chiropractic and osteopathy) results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons. Methods Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields which included the lumbar dorsal-lateral trunk were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in three directions (dorsal-ventral, 45°caudalward, and 45°cranialward) prior to and immediately following the dorsal-ventral delivery of a 100ms HVLA-SM at three thrust magnitudes (control, 55%, 85% body weight; (BW)). Results There was a significant difference in mechanical threshold between 85% BW manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (p=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude. Conclusions This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds. PMID:24928636

  7. Effect of spinal manipulation thrust magnitude on trunk mechanical activation thresholds of lateral thalamic neurons.

    Science.gov (United States)

    Reed, William R; Pickar, Joel G; Sozio, Randall S; Long, Cynthia R

    2014-06-01

    High-velocity low-amplitude spinal manipulation (HVLA-SM), as performed by doctors who use manual therapy (eg, doctors of chiropractic and osteopathy), results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons. Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields, which included the lumbar dorsal-lateral trunk, were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in 3 directions (dorsal-ventral, 45° caudalward, and 45° cranialward) before and immediately after the dorsal-ventral delivery of a 100-millisecond HVLA-SM at 3 thrust magnitudes (control, 55%, 85% body weight). There was a significant difference in mechanical threshold between 85% body weight manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (P=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude. This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that, at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds. Copyright © 2014 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  8. Differential effects of petit mal anticonvulsants and convulsants on thalamic neurones: GABA current blockade.

    OpenAIRE

    COULTER, D. A.; Huguenard, J. R.; PRINCE, D. A.

    1990-01-01

    1. Currents evoked by applications of gamma-aminobutyric acid (GABA) to acutely dissociated thalamic neurones were analysed by voltage-clamp techniques, and the effects of the anticonvulsant succinimides ethosuximide (ES) and alpha-methyl-alpha-phenylsuccinimide (MPS) and the convulsants tetramethylsuccinimide (TMS), picrotoxin, pentylenetetrazol (PTZ), and bicuculline methiodide were assessed. 2. TMS (1 microM-10 microM) reduced responses to iontophoretically applied GABA, as did picrotoxin ...

  9. Clinical Analysis of Thalamic Hemorrhage%丘脑出血的临床分析

    Institute of Scientific and Technical Information of China (English)

    张红莲

    2015-01-01

    Objective To investigate the clinical characteristics, prognosis and the relationship between thalamic hemor hage.Methods The clinical data of 20 patients with thalamic hemor hage and the results of CT examination were analyzed. Results Hypertension was the main cause of thalamic hemor hage;the amount of bleeding was less, and the prognosis was good, the bleeding volume was large and the complications occur ed early and the prognosis was worse. Conclusion The prognosis of thalamic hemor hage and blood pressure, bleeding volume, the complications of upper gastrointestinal bleeding within 24 hours, and whether or not to break into the ventricles of the brain.%目的:探讨丘脑出血的临床特点、预后及两者的关系。方法对20例丘脑出血患者的临床资料及头颅CT检查的结果进行分析。结果高血压是丘脑出血的主要原因;出血量少且局限的丘脑出血预后好、出血量大、并发症出现早且破入脑室的预后差。结论丘脑出血的预后与血压、出血量的多少、24h内出现上消化道出血的并发症及是否与破入脑室有关。

  10. Disrupted Auto-Activation, Dysexecutive and Confabulating Syndrome Following Bilateral Thalamic and Right Putaminal Stroke

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    Lieve De Witte

    2008-01-01

    Full Text Available Objective: Clinical, neuropsychological, structural and functional neuroimaging results are reported in a patient who developed a unique combination of symptoms after a bi-thalamic and right putaminal stroke. The symptoms consisted of dysexecutive disturbances associated with confabulating behavior and auto-activation deficits. Background: Basal ganglia and thalamic lesions may result in a variety of motor, sensory, neuropsychological and behavioral syndromes. However, the combination of a dysexecutive syndrome complicated at the behavioral level with an auto-activation and confabulatory syndrome has never been reported. Methods: Besides clinical and neuroradiological investigations, an extensive set of standardized neuropsychological tests was carried out. Results: In the post-acute phase of the stroke, a dysexecutive syndrome was found in association with confabulating behavior and auto-activation deficits. MRI showed focal destruction of both thalami and the right putamen. Quantified ECD SPECT revealed bilateral hypoperfusions in the basal ganglia and thalamus but no perfusion deficits were found at the cortical level. Conclusion: The combination of disrupted auto-activation, dysexecutive and confabulating syndrome in a single patient following isolated subcortical damage renders this case exceptional. Although these findings do not reveal a functional disruption of the striato-ventral pallidal-thalamic-frontomesial limbic circuitry, they add to the understanding of the functional role of the basal ganglia in cognitive and behavioral syndromes.

  11. Dissociable effects of anterior and mediodorsal thalamic lesions on spatial goal-directed behavior.

    Science.gov (United States)

    Alcaraz, Fabien; Naneix, Fabien; Desfosses, Emilie; Marchand, Alain R; Wolff, Mathieu; Coutureau, Etienne

    2016-01-01

    Goal-directed behaviors are thought to be supported by a neural circuit encompassing the prefrontal cortex, the dorsomedial striatum, the amygdala, and, as more recently suggested, the limbic thalamus. Since evidence indicates that the various thalamic nuclei contribute to dissociable functions, we directly compared the functional contribution of the mediodorsal thalamus (MD) and of the anterior thalamic nuclei (ATN) in a new task assessing spatial goal-directed behavior in a cross-maze. Rats sustaining lesions of the mediodorsal or the anterior thalamus were trained to associate each of the two goal arms with a distinctive food reward. Unlike control rats, both lesioned groups failed to express a bias for the goal arm corresponding to the non-devalued outcome following devaluation by sensory-specific satiety. In addition, MD rats were slower than the other groups to complete the trials. When tested for spatial working memory using a standard non-matching-to-place procedure in the same apparatus, ATN rats were severely impaired but MD rats performed as well as controls, even when spatial or temporal challenges were introduced. Finally, all groups displayed comparable breaking points in a progressive ratio test, indicating that the slower choice performance of MD rats did not result from motivational factors. Thus, a spatial task requiring the integration of instrumental and Pavlovian contingencies reveals a fundamental deficit of MD rats in adapting their choice according to goal value. By contrast, the deficit associated with anterior thalamic lesions appears to simply reflect the inability to process spatial information.

  12. [Typical Patterns of Neuronal Activity in Relay and Nonspecific Thalamic Nuclei in Patients with Spasmodic Torticollis].

    Science.gov (United States)

    Devetiarov, D A; Semenova, U N; Butiaeva, L I; Sedov, A S

    2015-01-01

    Neuronal activity of 50 neurons in nonspecific (Rt, MD) and relay (Voi, Voa) thalamic nuclei was analyzed. Data were obtained by microelectrode technique during 14 stereotactic operations in patients with spasmodic torticollis. Application of Poincare maps and Gap-statistics allowed to reveal 3 main patterns of neuronal activity: irregular single spikes, low-threshold Ca(2+)-dependent rhythmic (3-5 Hz) bursts and combination of bursts and single spikes. In some cases, grouping (in Voi and Rt nuclei) and long burst (in Voa nucleus) patterns were observed. Grouping pattern consist of low-density groups of spikes with tendency to periodicity in range 1-1.5 Hz. Long burst pattern consist of long dense groups of spikes with random length and invariant interburst intervals. Main numerical estimations of 3 most spread patterns of neuronal activity were obtained by parametric analysis. In results, investigated thalamic nuclei significantly distinguished from each other by characteristics of burst activity but average firing rate of these nuclei hadn't significant differences. These data may be useful for functional identification of thalamic nuclei during stereotactic neurosurgery operation in patients with movement disorders.

  13. OCCLUSION OF ARTERY OF PERCHERON: A RARE AETIOLOGY OF BILATERAL THALAMIC INFARCT

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    Mane Makarand, Mane Priyanka, Mohite Rajsinh , Bhattad Prashant, Bangar Kushal, Mahajani Anup

    2015-10-01

    Full Text Available The Artery of Percheron, a rare anatomical variant of brain vascularisation, arises from the posterior cerebral artery. Occlusion of this artery leads to bilateral paramedian thalamic infarct leads to dysfunction of central nervous system. Incidence of bilateral thalamic infarct secondary to occlusion of artery of Percheron is unknown because of its rarity. Here we report a case of 35 year old female presented with altered state of consciousness and the underlying cause was occlusion of Artery of Percheron which leads to bilateral thalamic infarct detected on MRI scanning. It showed hyperintensities on T2W1 and FLAIR, and hypointensity on T1W1, restricted to bilateral ventromedial thalami showing corresponding area of high signal intensity on diffusion weighted images and hypointensity on apparent diffusion coefficient images indicating diffusion restriction, suggestive of infarct. On further investigation magnetic resonance arteriogram (MRA of the brain demonstrated a single common artery arising from the left P1 segment which divided into two branches distally supplying bilateral thalami. Patient became alright after 2 weeks of medical line of treatment.

  14. Thalamic network oscillations synchronize ontogenetic columns in the newborn rat barrel cortex.

    Science.gov (United States)

    Yang, Jenq-Wei; An, Shuming; Sun, Jyh-Jang; Reyes-Puerta, Vicente; Kindler, Jennifer; Berger, Thomas; Kilb, Werner; Luhmann, Heiko J

    2013-06-01

    Neocortical areas are organized in columns, which form the basic structural and functional modules of intracortical information processing. Using voltage-sensitive dye imaging and simultaneous multi-channel extracellular recordings in the barrel cortex of newborn rats in vivo, we found that spontaneously occurring and whisker stimulation-induced gamma bursts followed by longer lasting spindle bursts were topographically organized in functional cortical columns already at the day of birth. Gamma bursts synchronized a cortical network of 300-400 µm in diameter and were coherent with gamma activity recorded simultaneously in the thalamic ventral posterior medial (VPM) nucleus. Cortical gamma bursts could be elicited by focal electrical stimulation of the VPM. Whisker stimulation-induced spindle and gamma bursts and the majority of spontaneously occurring events were profoundly reduced by the local inactivation of the VPM, indicating that the thalamus is important to generate these activity patterns. Furthermore, inactivation of the barrel cortex with lidocaine reduced the gamma activity in the thalamus, suggesting that a cortico-thalamic feedback loop modulates this early thalamic network activity.

  15. Thalamic haemorrhage vs internal capsule-basal ganglia haemorrhage: clinical profile and predictors of in-hospital mortality

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    García-Eroles Luis

    2007-10-01

    Full Text Available Abstract Background There is a paucity of clinical studies focused specifically on intracerebral haemorrhages of subcortical topography, a subject matter of interest to clinicians involved in stroke management. This single centre, retrospective study was conducted with the following objectives: a to describe the aetiological, clinical and prognostic characteristics of patients with thalamic haemorrhage as compared with that of patients with internal capsule-basal ganglia haemorrhage, and b to identify predictors of in-hospital mortality in patients with thalamic haemorrhage. Methods Forty-seven patients with thalamic haemorrhage were included in the "Sagrat Cor Hospital of Barcelona Stroke Registry" during a period of 17 years. Data from stroke patients are entered in the stroke registry following a standardized protocol with 161 items regarding demographics, risk factors, clinical features, laboratory and neuroimaging data, complications and outcome. The region of the intracranial haemorrhage was identified on computerized tomographic (CT scans and/or magnetic resonance imaging (MRI of the brain. Results Thalamic haemorrhage accounted for 1.4% of all cases of stroke (n = 3420 and 13% of intracerebral haemorrhage (n = 364. Hypertension (53.2%, vascular malformations (6.4%, haematological conditions (4.3% and anticoagulation (2.1% were the main causes of thalamic haemorrhage. In-hospital mortality was 19% (n = 9. Sensory deficit, speech disturbances and lacunar syndrome were significantly associated with thalamic haemorrhage, whereas altered consciousness (odds ratio [OR] = 39.56, intraventricular involvement (OR = 24.74 and age (OR = 1.23, were independent predictors of in-hospital mortality. Conclusion One in 8 patients with acute intracerebral haemorrhage had a thalamic hematoma. Altered consciousness, intraventricular extension of the hematoma and advanced age were determinants of a poor early outcome.

  16. Cortically-controlled population stochastic facilitation as a plausible substrate for guiding sensory transfer across the thalamic gateway.

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    Sébastien Béhuret

    Full Text Available The thalamus is the primary gateway that relays sensory information to the cerebral cortex. While a single recipient cortical cell receives the convergence of many principal relay cells of the thalamus, each thalamic cell in turn integrates a dense and distributed synaptic feedback from the cortex. During sensory processing, the influence of this functional loop remains largely ignored. Using dynamic-clamp techniques in thalamic slices in vitro, we combined theoretical and experimental approaches to implement a realistic hybrid retino-thalamo-cortical pathway mixing biological cells and simulated circuits. The synaptic bombardment of cortical origin was mimicked through the injection of a stochastic mixture of excitatory and inhibitory conductances, resulting in a gradable correlation level of afferent activity shared by thalamic cells. The study of the impact of the simulated cortical input on the global retinocortical signal transfer efficiency revealed a novel control mechanism resulting from the collective resonance of all thalamic relay neurons. We show here that the transfer efficiency of sensory input transmission depends on three key features: i the number of thalamocortical cells involved in the many-to-one convergence from thalamus to cortex, ii the statistics of the corticothalamic synaptic bombardment and iii the level of correlation imposed between converging thalamic relay cells. In particular, our results demonstrate counterintuitively that the retinocortical signal transfer efficiency increases when the level of correlation across thalamic cells decreases. This suggests that the transfer efficiency of relay cells could be selectively amplified when they become simultaneously desynchronized by the cortical feedback. When applied to the intact brain, this network regulation mechanism could direct an attentional focus to specific thalamic subassemblies and select the appropriate input lines to the cortex according to the descending

  17. Cortically-Controlled Population Stochastic Facilitation as a Plausible Substrate for Guiding Sensory Transfer across the Thalamic Gateway

    Science.gov (United States)

    Béhuret, Sébastien; Deleuze, Charlotte; Gomez, Leonel; Frégnac, Yves; Bal, Thierry

    2013-01-01

    The thalamus is the primary gateway that relays sensory information to the cerebral cortex. While a single recipient cortical cell receives the convergence of many principal relay cells of the thalamus, each thalamic cell in turn integrates a dense and distributed synaptic feedback from the cortex. During sensory processing, the influence of this functional loop remains largely ignored. Using dynamic-clamp techniques in thalamic slices in vitro, we combined theoretical and experimental approaches to implement a realistic hybrid retino-thalamo-cortical pathway mixing biological cells and simulated circuits. The synaptic bombardment of cortical origin was mimicked through the injection of a stochastic mixture of excitatory and inhibitory conductances, resulting in a gradable correlation level of afferent activity shared by thalamic cells. The study of the impact of the simulated cortical input on the global retinocortical signal transfer efficiency revealed a novel control mechanism resulting from the collective resonance of all thalamic relay neurons. We show here that the transfer efficiency of sensory input transmission depends on three key features: i) the number of thalamocortical cells involved in the many-to-one convergence from thalamus to cortex, ii) the statistics of the corticothalamic synaptic bombardment and iii) the level of correlation imposed between converging thalamic relay cells. In particular, our results demonstrate counterintuitively that the retinocortical signal transfer efficiency increases when the level of correlation across thalamic cells decreases. This suggests that the transfer efficiency of relay cells could be selectively amplified when they become simultaneously desynchronized by the cortical feedback. When applied to the intact brain, this network regulation mechanism could direct an attentional focus to specific thalamic subassemblies and select the appropriate input lines to the cortex according to the descending influence of

  18. Neuroinflammation and oxidative stress in rostral ventrolateral medulla contribute to neurogenic hypertension induced by systemic inflammation

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    Wu Kay LH

    2012-09-01

    Full Text Available Abstract Background In addition to systemic inflammation, neuroinflammation in the brain, which enhances sympathetic drive, plays a significant role in cardiovascular diseases, including hypertension. Oxidative stress in rostral ventrolateral medulla (RVLM that augments sympathetic outflow to blood vessels is involved in neural mechanism of hypertension. We investigated whether neuroinflammation and oxidative stress in RVLM contribute to hypertension following chronic systemic inflammation. Methods In normotensive Sprague-Dawley rats, systemic inflammation was induced by infusion of Escherichia coli lipopolysaccharide (LPS into the peritoneal cavity via an osmotic minipump. Systemic arterial pressure and heart rate were measured under conscious conditions by the non-invasive tail-cuff method. The level of the inflammatory markers in plasma or RVLM was analyzed by ELISA. Protein expression was evaluated by Western blot or immunohistochemistry. Tissue level of superoxide anion (O2·- in RVLM was determined using the oxidation-sensitive fluorescent probe dihydroethidium. Pharmacological agents were delivered either via infusion into the cisterna magna with an osmotic minipump or microinjection bilaterally into RVLM. Results Intraperitoneal infusion of LPS (1.2 mg/kg/day for 14 days promoted sustained hypertension and induced a significant increase in plasma level of C-reactive protein, tumor necrosis factor-α (TNF-α, or interleukin-1β (IL-1β. This LPS-induced systemic inflammation was accompanied by activation of microglia, augmentation of IL-1β, IL-6, or TNF-α protein expression, and O2·- production in RVLM, all of which were blunted by intracisternal infusion of a cycloxygenase-2 (COX-2 inhibitor, NS398; an inhibitor of microglial activation, minocycline; or a cytokine synthesis inhibitor, pentoxifylline. Neuroinflammation in RVLM was also associated with a COX-2-dependent downregulation of endothelial nitric oxide synthase and an

  19. Processing Complex Sounds Passing through the Rostral Brainstem: The New Early Filter Model.

    Science.gov (United States)

    Marsh, John E; Campbell, Tom A

    2016-01-01

    The rostral brainstem receives both "bottom-up" input from the ascending auditory system and "top-down" descending corticofugal connections. Speech information passing through the inferior colliculus of elderly listeners reflects the periodicity envelope of a speech syllable. This information arguably also reflects a composite of temporal-fine-structure (TFS) information from the higher frequency vowel harmonics of that repeated syllable. The amplitude of those higher frequency harmonics, bearing even higher frequency TFS information, correlates positively with the word recognition ability of elderly listeners under reverberatory conditions. Also relevant is that working memory capacity (WMC), which is subject to age-related decline, constrains the processing of sounds at the level of the brainstem. Turning to the effects of a visually presented sensory or memory load on auditory processes, there is a load-dependent reduction of that processing, as manifest in the auditory brainstem responses (ABR) evoked by to-be-ignored clicks. Wave V decreases in amplitude with increases in the visually presented memory load. A visually presented sensory load also produces a load-dependent reduction of a slightly different sort: The sensory load of visually presented information limits the disruptive effects of background sound upon working memory performance. A new early filter model is thus advanced whereby systems within the frontal lobe (affected by sensory or memory load) cholinergically influence top-down corticofugal connections. Those corticofugal connections constrain the processing of complex sounds such as speech at the level of the brainstem. Selective attention thereby limits the distracting effects of background sound entering the higher auditory system via the inferior colliculus. Processing TFS in the brainstem relates to perception of speech under adverse conditions. Attentional selectivity is crucial when the signal heard is degraded or masked: e.g., speech in

  20. Effects of Prolactin and Lactation on A15 Dopamine Neurones in the Rostral Preoptic Area of Female Mice.

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    Brown, R S E; Herbison, A E; Grattan, D R

    2015-09-01

    There are several distinct populations of dopamine neurones in the hypothalamus. Some of these, such as the A12 tuberoinfundibular dopamine neurones and the A14 periventricular dopamine neurones, are known to be regulated by the anterior pituitary hormone prolactin, whereas others, such as the A13 zona incerta dopaminergic neurones, are not. The present study aimed to investigate the role of prolactin in the regulation of a fourth population of hypothalamic dopamine neurones: the A15 dopamine population in the rostral hypothalamus. These neurones may play a role in the regulation of gonadotrophin-releasing hormone (GnRH) secretion, and we hypothesised that they might contribute to the suppression of GnRH release and infertility caused by hyperprolactinaemia. Under basal (low prolactin) conditions, only 8% of A15 dopamine neurones in the anteroventral periventricular nucleus (AVPV) of vehicle-treated dioestrous mice expressed phosphorylated signal transducer and activator of transcription 5 (pSTAT5), as labelled by immunohistochemistry. We have previously shown that this transcription factor can be used as an index of prolactin-receptor activation. Following acute prolactin administration, 35% of AVPV dopamine neurones co-expressed pSTAT5, whereas, during lactation, when endogenous prolactin levels are chronically elevated, 55% of AVPV dopamine neurones expressed pSTAT5. There was also a significant increase in dopamine turnover in the rostral hypothalamus, both in the diagonal band of Broca at the level of the organum vasculosum of the lamina terminalis and in the rostral preoptic area during lactation, with the 3,4-dihydroxyphenylacetic acid/dopamine ratio increasing from 0.28 ± 0.04 and 0.14 ± 0.01 in dioestrous mice to 0.82 ± 0.06 and 0.38 ± 0.03, respectively, in day 7 lactating mice. It is not yet known whether this change is driven by the hyperprolactinaemia of lactation, or another lactation-specific signal. These data demonstrate that the A15

  1. Automatic Measurement of Thalamic Diameter in 2-D Fetal Ultrasound Brain Images Using Shape Prior Constrained Regularized Level Sets.

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    Sridar, Pradeeba; Kumar, Ashnil; Li, Changyang; Woo, Joyce; Quinton, Ann; Benzie, Ron; Peek, Michael J; Feng, Dagan; Kumar, R Krishna; Nanan, Ralph; Kim, Jinman

    2017-07-01

    We derived an automated algorithm for accurately measuring the thalamic diameter from 2-D fetal ultrasound (US) brain images. The algorithm overcomes the inherent limitations of the US image modality: nonuniform density; missing boundaries; and strong speckle noise. We introduced a "guitar" structure that represents the negative space surrounding the thalamic regions. The guitar acts as a landmark for deriving the widest points of the thalamus even when its boundaries are not identifiable. We augmented a generalized level-set framework with a shape prior and constraints derived from statistical shape models of the guitars; this framework was used to segment US images and measure the thalamic diameter. Our segmentation method achieved a higher mean Dice similarity coefficient, Hausdorff distance, specificity, and reduced contour leakage when compared to other well-established methods. The automatic thalamic diameter measurement had an interobserver variability of -0.56 ± 2.29 mm compared to manual measurement by an expert sonographer. Our method was capable of automatically estimating the thalamic diameter, with the measurement accuracy on par with clinical assessment. Our method can be used as part of computer-assisted screening tools that automatically measure the biometrics of the fetal thalamus; these biometrics are linked to neurodevelopmental outcomes.

  2. Comparison of numbers of interneurons in three thalamic nuclei of normal and epileptic rats.

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    Cavdar, Safiye; Bay, Hüsniye Hacioğlu; Yildiz, Sercan D; Akakin, Dilek; Sirvanci, Serap; Onat, Filiz

    2014-06-01

    The inhibitory sources in the thalamic nuclei are local interneurons and neurons of the thalamic reticular nucleus. Studies of models of absence epilepsy have shown that the seizures are associated with an excess of inhibitory neurotransmission in the thalamus. In the present study, we used light-microscopic gamma-aminobutyric acid (GABA) immunocytochemistry to quantify the interneurons in the lateral geniculate (LGN), ventral posteromedial (VPM), and ventral posterolateral (VPL) thalamic nuclei, and compared the values from normal Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS). We found that in both Wistar rats and GAERS, the proportion of interneurons was significantly higher in the LGN than in the VPM and VPL. In the LGN of Wistar rats, 16.4% of the neurons were interneurons and in the GAERS, the value was 15.1%. In the VPM, the proportion of interneurons was 4.2% in Wistar and 14.9% in GAERS; in the VPL the values were 3.7% for Wistar and 11.1% for the GAERS. There was no significant difference between Wistar rats and the GAERS regarding the counts of interneurons in the LGN, whereas the VPM and VPL showed significantly higher counts in GAERS. Comparison of the mean areas of both relay cells and interneuronal profiles showed no significant differences between Wistar rats and GAERS. These findings show that in the VPL and the VPM there are relatively more GABAergic interneurons in GAERS than in Wistar rats. This may represent a compensatory response of the thalamocortical circuitry to the absence seizures or may be related to the production of absence seizures.

  3. Practical CT classification for thalamic hemorrhage. Relationship between localization of hematoma and prognosis

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    Kurita, Hiroki; Furuya, Kazuhide; Segawa, Hiromu; Taniguchi, Tamiki; Sano, Keiji (Fuji Brain Inst. and Hospital, Shizuoka (Japan)); Shiokawa, Yoshiaki

    1994-06-01

    The study was designed to establish CT classification for predicting prognosis of thalamic hemorrhage. A retrospective analysis was made on CT scans from 100 patients with hypertensive thalamic hemorrhage less than 4 cm. Four lines were drawn on axial CT scans at the level of the pineal body: (A) line between the lateral edge of the anterior horn and the midpoint of the third ventricle; (B) vertebral line to the sagittal line from the midpoint of the third ventricle; (C) line between the lateral edge of the trigone and the midpoint of the third ventricle; and (D) line between the lateral edge of the anterior horn and the lateral edge of the trigone. According to the lateral extension, the location of hematoma fell into three types: anterior type in which the center of hematoma was located between lines A and B (type A); posterior type in which the center of hematoma was located between lines B and C and external margin of hematoma was localized medial to line D (type P); postero-lateral type in which the center of hematoma was located between lines B and C and showed lateral extension beyond line D (type PL). Severe hemiparesis was observed in 15.3% for type A, 21.8% for type P, and 59.3% for type PL. Good prognosis was seen in 84.7% for type A, 70.9% for type P, and 12.5% for type PL. Acute disturbance of consciousness was significantly observed in patients with medial extension of hematoma (86.4%) as compared with those without it (21.4%). These results indicated that CT classification is a simple means for predicting functional outcome of motor paresis and consciousness disturbance in patients with thalamic hemorrhage. (N.K.).

  4. Volatile anesthetic action in a computational model of the thalamic reticular nucleus.

    Science.gov (United States)

    Gottschalk, Allan; Miotke, Sam A

    2009-05-01

    Although volatile anesthetics (VAs) modulate the activity of multiple ion channels, the process whereby one or more of these effects are integrated to produce components of the general anesthetic state remains enigmatic. Computer models offer the opportunity to examine systems level effects of VA action at one or more sites. Motivated by the role of the thalamus in consciousness and sensory processing, a computational model of the thalamic reticular nucleus was used to determine the collective impact on model behavior of VA action at multiple sites. A computational model of the thalamic reticular nucleus was modified to permit VA modulation of its ion channels. Isobolographic analysis was used to determine how multiple sites interact. VA modulation of either T-type Ca(2+) channels or gamma-aminobutyric acid type A receptors led to increased network synchrony. VA modulation of both further increased network synchronization. VA-induced decrements in Ca(2+) current permitted greater impact of inhibitory currents on membrane potential, but at higher VA concentrations the decrease in Ca(2+) current led to a decreased number of spikes in the burst generating the inhibitory signal. MAC-awake (the minimum alveolar concentration at which 50% of subjects will recover consciousness) concentrations of both isoflurane and halothane led to similar levels of network synchrony in the model. Relatively modest VA effects at both T-type Ca(2+) channels and gamma-aminobutyric acid type A receptors can substantially alter network behavior in a computational model of a thalamic nucleus. The similarity of network behavior at MAC-awake concentrations of different VAs is consistent with a contribution of the thalamus to VA-induced unconsciousness through action at these channels.

  5. Thalamic gap junctions control local neuronal synchrony and influence macroscopic oscillation amplitude during EEG alpha rhythms

    Directory of Open Access Journals (Sweden)

    Stuart eHughes

    2011-08-01

    Full Text Available Although EEG alpha ( (8-13 Hz rhythms are often considered to reflect an ‘idling’ brain state, numerous studies indicate that they are also related to many aspects of perception. Recently, we outlined a potential cellular substrate by which such aspects of perception might be linked to basic  rhythm mechanisms. This scheme relies on a specialized subset of rhythmically bursting thalamocortical (TC neurons (high-threshold bursting cells in the lateral geniculate nucleus (LGN which are interconnected by gap junctions (GJs. By engaging GABAergic interneurons, that in turn inhibit conventional relay-mode TC neurons, these cells can lead to an effective temporal framing of thalamic relay-mode output. Although the role of GJs is pivotal in this scheme, evidence for their involvement in thalamic  rhythms has thus far mainly derived from experiments in in vitro slice preparations. In addition, direct anatomical evidence of neuronal GJs in the LGN is currently lacking. To address the first of these issues we tested the effects of the GJ inhibitors, carbenoxolone (CBX and 18-glycyrrhetinic acid (18-GA, given directly to the LGN via reverse microdialysis, on spontaneous LGN and EEG  rhythms in behaving cats. We also examined the effect of CBX on  rhythm-related LGN unit activity. Indicative of a role for thalamic GJs in these activities, 18-GA and CBX reversibly suppressed both LGN and EEG  rhythms, with CBX also decreasing neuronal synchrony. To address the second point, we used electron microscopy to obtain definitive ultrastructural evidence for the presence of GJs between neurons in the cat LGN. As interneurons show no phenotypic evidence of GJ coupling (i.e. dye-coupling and spikelets we conclude that these GJs must belong to TC neurons. The potential significance of these findings for relating macroscopic changes in  rhythms to basic cellular processes is discussed.

  6. The importance of combinatorial gene expression in early mammalian thalamic patterning and thalamocortical axonal guidance

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    David J Price

    2012-03-01

    Full Text Available The thalamus is essential for sensory perception. In mammals, work on the mouse has taught us most of what we know about how it develops and connects to the cortex. The mature thalamus of all mammalian species comprises numerous anatomically distinct collections of neurons called nuclei that differ in function, connectivity and molecular constitution. At the time of its initial appearance as a distinct structure following neural tube closure, the thalamus is already patterned by the regional expression of numerous regulatory genes. This patterning, which lays down the blueprint for later development of thalamic nuclei, predates the development of thalamocortical projections. In this review we apply novel analytical methods to gene expression data available in the Allen Developing Mouse Brain Atlas to highlight the complex organized molecular heterogeneity already present among cells in the thalamus from the earliest stages at which it contains differentiating neurons. This early patterning is likely to invest in axons growing from different parts of the thalamus the ability to navigate in an ordered way to their appropriate area in the cerebral cortex. We review the mechanisms and cues that thalamic axons use, encounter and interpret to attain the cortex. Mechanisms include guidance by previously-generated guidepost cells, such as those in the subpallium that maintain thalamic axonal order and direction, and axons such as those of reciprocal projections from intermediate structures or from the cortex itself back towards the thalamus. We show how thalamocortical pathfinding involves numerous guidance cues operating at a series of steps along their route. We stress the importance of the combinatorial actions of multiple genes for the development of the numerous specific identities and functions of cells in this exquisitely complex system and their orderly innervation of the cortex.

  7. Thalamic lesion and epilepsy with generalized seizures, ESES and spike-wave paroxysms--report of three cases.

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    Kelemen, Anna; Barsi, Péter; Gyorsok, Zsuzsanna; Sarac, Judit; Szucs, Anna; Halász, Péter

    2006-09-01

    We report three patients, who have thalamic lesion and secondary generalized epilepsy with generalized spike wave pattern. The first two patients have unilateral perinatal lesion, one with generalized tonic-clonic seizures on awakening the other with Landau-Kleffner-like syndrome. During the course of the disease both children developed electrical status epilepticus in slow wave sleep (ESES). The third patient has a dominantly unilateral thalamic tumor and epilepsy that mimics juvenile myoclonic epilepsy. All the patients have a lesion located in the inferior-medial-posterior part of the thalamus. The role of some thalamic and subthalamic nuclei in the generalized spike-wave electrical pattern patophysiology is discussed, with emphasis on the possible role of the inhibitory system from the zona incerta.

  8. Multimodal quantitative magnetic resonance imaging of thalamic development and aging across the human lifespan: implications to neurodegeneration in multiple sclerosis.

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    Hasan, Khader M; Walimuni, Indika S; Abid, Humaira; Frye, Richard E; Ewing-Cobbs, Linda; Wolinsky, Jerry S; Narayana, Ponnada A

    2011-11-16

    The human brain thalami play essential roles in integrating cognitive, sensory, and motor functions. In multiple sclerosis (MS), quantitative magnetic resonance imaging (qMRI) measurements of the thalami provide important biomarkers of disease progression, but late development and aging confound the interpretation of data collected from patients over a wide age range. Thalamic tissue volume loss due to natural aging and its interplay with lesion-driven pathology has not been investigated previously. In this work, we used standardized thalamic volumetry combined with diffusion tensor imaging, T2 relaxometry, and lesion mapping on large cohorts of controls (N = 255, age range = 6.2-69.1 years) and MS patients (N = 109, age range = 20.8-68.5 years) to demonstrate early age- and lesion-independent thalamic neurodegeneration.

  9. Thalamic GABA levels and occupational manganese neurotoxicity: Association with exposure levels and brain MRI.

    Science.gov (United States)

    Ma, Ruoyun E; Ward, Eric J; Yeh, Chien-Lin; Snyder, Sandy; Long, Zaiyang; Gokalp Yavuz, Fulya; Zauber, S Elizabeth; Dydak, Ulrike

    2017-09-02

    Excessive occupational exposure to Manganese (Mn) has been associated with clinical symptoms resembling idiopathic Parkinson's disease (IPD), impairing cognitive and motor functions. Several studies point towards an involvement of the brain neurotransmitter system in Mn intoxication, which is hypothesized to be disturbed prior to onset of symptoms. Edited Magnetic Resonance Spectroscopy (MRS) offers the unique possibility to measure γ-amminobutyric acid (GABA) and other neurometabolites in vivo non-invasively in workers exposed to Mn. In addition, the property of Mn as Magnetic Resonance Imaging (MRI) contrast agent may be used to study Mn deposition in the human brain. In this study, using MRI, MRS, personal air sampling at the working place, work history questionnaires, and neurological assessment (UPDRS-III), the effects of chronic Mn exposure on the thalamic GABAergic system was studied in a group of welders (N=39) with exposure to Mn fumes in a typical occupational setting. Two subgroups of welders with different exposure levels (Low: N=26; mean air Mn=0.13±0.1mg/m(3); High: N=13; mean air Mn=0.23±0.18mg/m(3)), as well as unexposed control workers (N=22, mean air Mn=0.002±0.001mg/m(3)) were recruited. The group of welders with higher exposure showed a significant increase of thalamic GABA levels by 45% (p<0.01, F(1,33)=9.55), as well as significantly worse performance in general motor function (p<0.01, F(1,33)=11.35). However, welders with lower exposure did not differ from the controls in GABA levels or motor performance. Further, in welders the thalamic GABA levels were best predicted by past-12-months exposure levels and were influenced by the Mn deposition in the substantia nigra and globus pallidus. Importantly, both thalamic GABA levels and motor function displayed a non-linear pattern of response to Mn exposure, suggesting a threshold effect. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Thalamic hemorrhage in a 4-year-old child induced by nephro-vascular hypertension

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    Bianchi, E.; Savasta, S.; Torcetta, F.; Solmi, M.; Beluffi, G.; Gajno, T.M.

    1989-08-01

    A child affected by cardiomyopathy from the age of 12 months suddenly manifested right hemiparesis and dysarthria at the age of 48/12 years. Emergency brain CT showed a hemorrhage in progress in the left thalamic area. A serve from of hypertension was concomitant and resisted all pharmacological treatment. Retrograde transfemural aortography pointed out an atrophy of the right renal artery. This finding, together with the high renin and aldosterone values, indicated a nephrogenic hypertension causing both the cardiomyopathy found at 12 months of age and the endocranial hermorrhage. Right nephrectomy led to the normalization of blood pressure. (orig.).

  11. Regional thalamic neuropathology in patients with hippocampal sclerosis and epilepsy: A postmortem study

    Science.gov (United States)

    Sinjab, Barah; Martinian, Lillian; Sisodiya, Sanjay M; Thom, Maria

    2013-01-01

    Purpose Clinical, experimental, and neuroimaging data all indicate that the thalamus is involved in the network of changes associated with temporal lobe epilepsy (TLE), particularly in association with hippocampal sclerosis (HS), with potential roles in seizure initiation and propagation. Pathologic changes in the thalamus may be a result of an initial insult, ongoing seizures, or retrograde degeneration through reciprocal connections between thalamic and limbic regions. Our aim was to carry out a neuropathologic analysis of the thalamus in a postmortem (PM) epilepsy series, to assess the distribution, severity, and nature of pathologic changes and its association with HS. Methods Twenty-four epilepsy PM cases (age range 25–87 years) and eight controls (age range 38–85 years) were studied. HS was classified as unilateral (UHS, 11 cases), bilateral (BHS, 4 cases) or absent (No-HS, 9 cases). Samples from the left and right sides of the thalamus were stained with cresyl violet (CV), and for glial firbillary acidic protein (GFAP) and synaptophysin. Using image analysis, neuronal densities (NDs) or field fraction staining values (GFAP, synaptophysin) were measured in four thalamic nuclei: anteroventral nucleus (AV), lateral dorsal nucleus (LD), mediodorsal nucleus (MD), and ventrolateral nucleus (VL). The results were compared within and between cases. Key Findings The severity, nature, and distribution of thalamic pathology varied between cases. A pattern that emerged was a preferential involvement of the MD in UHS cases with a reduction in mean ND ipsilateral to the side of HS (p = 0.05). In UHS cases, greater field fraction values for GFAP and lower values for synaptophysin and ND were seen in the majority of cases in the MD ipsilateral to the side of sclerosis compared to other thalamic nuclei. In addition, differences in the mean ND between classical HS, atypical HS, and No-HS cases were noted in the ipsilateral MD (p < 0.05), with lower values observed in

  12. Anterior Thalamic High Frequency Band Activity Is Coupled with Theta Oscillations at Rest

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    Catherine M. Sweeney-Reed

    2017-07-01

    Full Text Available Cross-frequency coupling (CFC between slow and fast brain rhythms, in the form of phase–amplitude coupling (PAC, is proposed to enable the coordination of neural oscillatory activity required for cognitive processing. PAC has been identified in the neocortex and mesial temporal regions, varying according to the cognitive task being performed and also at rest. PAC has also been observed in the anterior thalamic nucleus (ATN during memory processing. The thalamus is active during the resting state and has been proposed to be involved in switching between task-free cognitive states such as rest, in which attention is internally-focused, and externally-focused cognitive states, in which an individual engages with environmental stimuli. It is unknown whether PAC is an ongoing phenomenon during the resting state in the ATN, which is modulated during different cognitive states, or whether it only arises during the performance of specific tasks. We analyzed electrophysiological recordings of ATN activity during rest from seven patients who received thalamic electrodes implanted for treatment of pharmacoresistant focal epilepsy. PAC was identified between theta (4–6 Hz phase and high frequency band (80–150 Hz amplitude during rest in all seven patients, which diminished during engagement in tasks involving an external focus of attention. The findings are consistent with the proposal that theta–gamma coupling in the ATN is an ongoing phenomenon, which is modulated by task performance.

  13. Striatum and globus pallidus control the electrical activity of reticular thalamic nuclei.

    Science.gov (United States)

    Villalobos, Nelson; Oviedo-Chávez, Aldo; Alatorre, Alberto; Ríos, Alain; Barrientos, Rafael; Delgado, Alfonso; Querejeta, Enrique

    2016-08-01

    Through GABAergic fibers, globus pallidus (GP) coordinates basal ganglia global function. Electrical activity of GP neurons depends on their membrane properties and afferent fibers, including GABAergic fibers from striatum. In pathological conditions, abnormal electrical activity of GP neurons is associated with motor deficits. There is a GABAergic pathway from the GP to the reticular thalamic nucleus (RTn) whose contribution to RTn neurons electrical activity has received little attention. This fact called our attention because the RTn controls the overall information flow of thalamic nuclei to cerebral cortex. Here, we study the spontaneous electrical activity of RTn neurons recorded in vivo in anesthetized rats and under pharmacological activation or inhibition of the GP. We found that activation of GP predominantly diminishes the spontaneous RTn neurons firing rate and its inhibition increases their firing rate; however, both activation and inhibition of GP did not modified the burst index (BI) or the coefficient of variation (CV) of RTn neurons. Moreover, stimulation of striatum predominantly diminishes the spiking rate of GP cells and increases the spiking rate in RTn neurons without modifying the BI or CV in reticular neurons. Our data suggest a GP tight control over RTn spiking activity.

  14. Thalamic nuclear abnormalities as a contributory factor in sudden cardiac deaths among patients with schizophrenia

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    Fulvio A. Scorza

    2010-01-01

    Full Text Available Patients with schizophrenia have a two- to three-fold increased risk of premature death as compared to patients without this disease. It has been established that patients with schizophrenia are at a high risk of developing cardiovascular disease. Moreover, an important issue that has not yet been explored is a possible existence of a "cerebral" focus that could trigger sudden cardiac death in patients with schizophrenia. Along these lines, several structural and functional alterations in the thalamic complex are evident in patients with schizophrenia and have been correlated with the symptoms manifested by these patients. With regard to abnormalities on the cellular and molecular level, previous studies have shown that schizophrenic patients have fewer neuronal projections from the thalamus to the prefrontal cortex as well as a reduced number of neurons, a reduced volume of either the entire thalamus or its subnuclei, and abnormal glutamate signaling. According to the glutamate hypothesis of schizophrenia, hypofunctional corticostriatal and striatothalamic projections are directly involved in the pathophysiology of the disease. Animal and post-mortem studies have provided a large amount of evidence that links the sudden unexpected death in epilepsy (SUDEP that occurs in patients with schizophrenia and epilepsy to thalamic changes. Based on the results of these prior studies, it is clear that further research regarding the relationship between the thalamus and sudden cardiac death is of vital importance.

  15. Thalamic mechanisms underlying alpha-delta sleep with implications for fibromyalgia.

    Science.gov (United States)

    Vijayan, Sujith; Klerman, Elizabeth B; Adler, Gail K; Kopell, Nancy J

    2015-09-01

    Alpha-delta sleep is the abnormal intrusion of alpha activity (8- to 13-Hz oscillations) into the delta activity (1- to 4-Hz oscillations) that defines slow-wave sleep. Alpha-delta sleep is especially prevalent in fibromyalgia patients, and there is evidence suggesting that the irregularities in the sleep of these patients may cause the muscle and tissue pain that characterizes the disorder. We constructed a biophysically realistic mathematical model of alpha-delta sleep. Imaging studies in fibromyalgia patients suggesting altered levels of activity in the thalamus motivated a thalamic model as the source of alpha activity. Since sodium oxybate helps to alleviate the symptoms of fibromyalgia and reduces the amount of alpha-delta sleep in fibromyalgia patients, we examined how changes in the molecular targets of sodium oxybate affected alpha-delta activity in our circuit. Our model shows how alterations in GABAB currents and two thalamic currents, Ih (a hyperpolarization-activated current) and a potassium leak current, transform a circuit that normally produces delta oscillations into one that produces alpha-delta activity. Our findings suggest that drugs that reduce Ih conductances and/or increase potassium conductances, without necessarily increasing GABAB conductances, might be sufficient to restore delta sleep. Furthermore, they suggest that delta sleep might be restored by drugs that preferentially target these currents in the thalamus; such drugs might have fewer side effects than drugs that act systemically.

  16. Thalamic input to distal apical dendrites in neocortical layer 1 is massive and highly convergent.

    Science.gov (United States)

    Rubio-Garrido, Pablo; Pérez-de-Manzo, Flor; Porrero, César; Galazo, Maria J; Clascá, Francisco

    2009-10-01

    Input to apical dendritic tufts is now deemed crucial for associative learning, attention, and similar "feedback" interactions in the cerebral cortex. Excitatory input to apical tufts in neocortical layer 1 has been traditionally assumed to be predominantly cortical, as thalamic pathways directed to this layer were regarded relatively scant and diffuse. However, the sensitive tracing methods used in the present study show that, throughout the rat neocortex, large numbers (mean approximately 4500/mm(2)) of thalamocortical neurons converge in layer 1 and that this convergence gives rise to a very high local density of thalamic terminals. Moreover, we show that the layer 1-projecting neurons are present in large numbers in most, but not all, motor, association, limbic, and sensory nuclei of the rodent thalamus. Some layer 1-projecting axons branch to innervate large swaths of the cerebral hemisphere, whereas others arborize within only a single cortical area. Present data imply that realistic modeling of cortical circuitry should factor in a dense axonal canopy carrying highly convergent thalamocortical input to pyramidal cell apical tufts. In addition, they are consistent with the notion that layer 1-projecting axons may be a robust anatomical substrate for extensive "feedback" interactions between cortical areas via the thalamus.

  17. T-type calcium channels consolidate tonic action potential output of thalamic neurons to neocortex.

    Science.gov (United States)

    Deleuze, Charlotte; David, François; Béhuret, Sébastien; Sadoc, Gérard; Shin, Hee-Sup; Uebele, Victor N; Renger, John J; Lambert, Régis C; Leresche, Nathalie; Bal, Thierry

    2012-08-29

    The thalamic output during different behavioral states is strictly controlled by the firing modes of thalamocortical neurons. During sleep, their hyperpolarized membrane potential allows activation of the T-type calcium channels, promoting rhythmic high-frequency burst firing that reduces sensory information transfer. In contrast, in the waking state thalamic neurons mostly exhibit action potentials at low frequency (i.e., tonic firing), enabling the reliable transfer of incoming sensory inputs to cortex. Because of their nearly complete inactivation at the depolarized potentials that are experienced during the wake state, T-channels are not believed to modulate tonic action potential discharges. Here, we demonstrate using mice brain slices that activation of T-channels in thalamocortical neurons maintained in the depolarized/wake-like state is critical for the reliable expression of tonic firing, securing their excitability over changes in membrane potential that occur in the depolarized state. Our results establish a novel mechanism for the integration of sensory information by thalamocortical neurons and point to an unexpected role for T-channels in the early stage of information processing.

  18. Differences in response to serotonergic activation between first and higher order thalamic nuclei.

    Science.gov (United States)

    Varela, C; Sherman, S Murray

    2009-08-01

    Two types of thalamic nuclei have been recognized: first order, which relay information from subcortical sources, and higher order, which may relay information from one cortical area to another. We have recently shown that muscarinic agonists depolarize all first order and most higher order relay cells but hyperpolarize a significant proportion of higher order relay cells. We now extend this result to serotonergic agonists, using rat thalamic brain slices and whole-cell, current- and voltage-clamp recordings from relay cells in various first order (the lateral geniculate nucleus, the ventral posterior nucleus, and the ventral portion of the medial geniculate body) and higher order nuclei (the lateral posterior, the posterior medial nucleus, and the dorsal portion of the medial geniculate body). Similar to the effects of muscarinic agonists, we found that first and most higher order relay cells were depolarized by serotonergic agonists, but 15% of higher order relay cells responded with hyperpolarization. Thus different subsets of higher order relay cells are hyperpolarized by these modulatory systems, which could have implications for the transfer of information between cortical areas.

  19. Thalamic Atrophy Contributes to Low Slow Wave Sleep in Neuromyelitis Optica Spectrum Disorder

    Science.gov (United States)

    Su, Lei; Han, Yujuan; Xue, Rong; Wood, Kristofer; Shi, Fu-Dong; Liu, Yaou; Fu, Ying

    2016-01-01

    Slow wave sleep abnormality has been reported in neuromyelitis optica spectrum disorder (NMOSD), but mechanism for such abnormality is unknown. To determine the structural defects in the brain that account for the decrease of slow wave sleep in NMOSD patients. Thirty-three NMOSD patients and 18 matched healthy controls (HC) were enrolled. Polysomnography was used to monitor slow wave sleep and three-dimensional T1-weighted MRIs were obtained to assess the alterations of grey matter volume. The percentage of deep slow wave sleep decreased in 93% NMOSD patients. Compared to HC, a reduction of grey matter volume was found in the bilateral thalamus of patients with a lower percentage of slow wave sleep (FWE corrected at cluster-level, p 400 voxels). Furthermore, the right thalamic fraction was positively correlated with the decrease in the percentage of slow wave sleep in NMOSD patients (p 200 voxels). Our study identified that thalamic atrophy is associated with the decrease of slow wave sleep in NMOSD patients. Further studies should evaluate whether neurotransmitters or hormones which stem from thalamus are involved in the decrease of slow wave sleep. PMID:28053819

  20. Case of herpes simplex encephalitis(HSE) with a thalamic lesion

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    Fujimori, K.; Koike, R.; Yuasa, T.; Miyatake, T.; Ito, J.

    1987-02-01

    A case of herpes simplex encephalitis (HSE) with thalamic involvement was reported. The patient, a 27-year-old man, was admitted because of abnormal behavior and fever. He exhibited a disturbance of consciousness, meningial signs, and hyperreflexia. A CT scan of the head revealed diffuse brain edema. Acute encephalitis, especially HSE, was suspected, and so the intravenous administration of acyclovir and steroid therapy were started. The titer of herpes simplex Type 1 virus, as measured by CF and ELISA, was found to have increased amounts of serum and cerebrospinal fluid. 5 days after the onset, his consciousness worsened. He could not tell his name and scarely opened his eyes upon pain stimulation. A CT scan at this time showed low-density lesions in the left thalamus, cingulate gyrus, and the posterior portion of the putamen. About 5 days later, his consciousness level was increased, but he was mute. This symptom was thought to be thalamic aphasia, which might be correlative with the low-density lesions shown in the left thalamus by the CT scan. About 30 days after the onset of the disease, his speech became normal, and a CT scan at 51 hospital days showed no abnormality. The etiology of low-density lesions of the left thalamus in the CT scan is speculated to be as follows: firstly, vascular damage of circulation disturbance, and secondly a special affinity of herpes simplex Type 1 virus to the thalamus.

  1. Persistence of disturbed thalamic glucose metabolism in a case of Wernicke-Korsakoff syndrome.

    Science.gov (United States)

    Fellgiebel, Andreas; Scheurich, Armin; Siessmeier, Thomas; Schmidt, Lutz G; Bartenstein, Peter

    2003-10-30

    We report the case of a 40-year-old alcoholic male patient, hospitalized with an acute ataxia of stance and gait, ocular muscle weakness with nystagmus and a global apathetic-confusional state. After admission, an amnestic syndrome with confabulation was also observed and diagnosis of Wernicke-Korsakoff syndrome was made. Under treatment with intravenous thiamine, the patient recovered completely from gaze weakness and ataxia, whereas a severe amnestic syndrome persisted. Fluorodeoxyglucose (FDG) positron emission tomography (PET) showed bilateral thalamic and severe bilateral temporal-parietal hypometabolism resembling a pattern typical for Alzheimer's disease. Longitudinal assessment of the alcohol-abstinent and thiamine-substituted patient revealed improvements of clinical state and neuropsychological performance that were paralleled by recovered cerebral glucose metabolism. In contrast to metabolic rates that increased between 7.1% (anterior cingulate, left) and 23.5% (parietal, left) in cortical areas during a 9-month remission period, thalamic glucose metabolism remained severely disturbed over time (change: left +0.2%, right +0.3%).

  2. Dural arteriovenous fistula-induced thalamic dementia: report of 4 cases.

    Science.gov (United States)

    Holekamp, Terrence F; Mollman, Matthew E; Murphy, Rory K J; Kolar, Grant R; Kramer, Neha M; Derdeyn, Colin P; Moran, Christopher J; Perrin, Richard J; Rich, Keith M; Lanzino, Giuseppe; Zipfel, Gregory J

    2016-06-01

    Nonhemorrhagic neurological deficits are underrecognized symptoms of intracranial dural arteriovenous fistulas (dAVFs) having cortical venous drainage. These symptoms are the consequence of cortical venous hypertension and portend a clinical course with increased risk of neurological morbidity and mortality. One rarely documented and easily misinterpreted type of nonhemorrhagic neurological deficit is progressive dementia, which can result from venous hypertension in the cortex or in bilateral thalami. The latter, which is due to dAVF drainage into the deep venous system, is the less common of these 2 dementia syndromes. Herein, the authors report 4 cases of dAVF with venous drainage into the vein of Galen causing bithalamic edema and rapidly progressive dementia. Two patients were treated successfully with endovascular embolization, and the other 2 patients were treated successfully with endovascular embolization followed by surgery. The radiographic abnormalities and presenting symptoms rapidly resolved after dAVF obliteration in all 4 cases. Detailed descriptions of these 4 cases are presented along with a critical review of 15 previously reported cases. In our analysis of these 19 published cases, the following were emphasized: 1) the clinical and radiographic differences between dAVF-induced thalamic versus cortical dementia syndromes; 2) the differential diagnosis and necessary radiographic workup for patients presenting with a rapidly progressive thalamic dementia syndrome; 3) the frequency at which delays in diagnosis occurred and potentially dangerous and avoidable diagnostic procedures were used; and 4) the rapidity and completeness of symptom resolution following dAVF treatment.

  3. Thalamic Atrophy Contributes to Low Slow Wave Sleep in Neuromyelitis Optica Spectrum Disorder.

    Science.gov (United States)

    Su, Lei; Han, Yujuan; Xue, Rong; Wood, Kristofer; Shi, Fu-Dong; Liu, Yaou; Fu, Ying

    2016-12-01

    Slow wave sleep abnormality has been reported in neuromyelitis optica spectrum disorder (NMOSD), but mechanism for such abnormality is unknown. To determine the structural defects in the brain that account for the decrease of slow wave sleep in NMOSD patients. Thirty-three NMOSD patients and 18 matched healthy controls (HC) were enrolled. Polysomnography was used to monitor slow wave sleep and three-dimensional T1-weighted MRIs were obtained to assess the alterations of grey matter volume. The percentage of deep slow wave sleep decreased in 93% NMOSD patients. Compared to HC, a reduction of grey matter volume was found in the bilateral thalamus of patients with a lower percentage of slow wave sleep (FWE corrected at cluster-level, p 400 voxels). Furthermore, the right thalamic fraction was positively correlated with the decrease in the percentage of slow wave sleep in NMOSD patients (p 200 voxels). Our study identified that thalamic atrophy is associated with the decrease of slow wave sleep in NMOSD patients. Further studies should evaluate whether neurotransmitters or hormones which stem from thalamus are involved in the decrease of slow wave sleep.

  4. Central thalamic deep brain stimulation for support of forebrain arousal regulation in the minimally conscious state.

    Science.gov (United States)

    Schiff, Nicholas D

    2013-01-01

    This chapter considers the use of central thalamic deep brain stimulation (CT/DBS) to support arousal regulation mechanisms in the minimally conscious state (MCS). CT/DBS for selected patients in a MCS is first placed in the historical context of prior efforts to use thalamic electrical brain stimulation to treat the unconscious clinical conditions of coma and vegetative state. These previous studies and a proof of concept result from a single-subject study of a patient in a MCS are reviewed against the background of new population data providing benchmarks of the natural history of vegetative and MCSs. The conceptual foundations for CT/DBS in selected patients in a MCS are then presented with consideration of both circuit and cellular mechanisms underlying recovery of consciousness identified from empirical studies. Directions for developing future generalizable criteria for CT/DBS that focus on the integrity of necessary brain systems and behavioral profiles in patients in a MCS that may optimally response to support of arousal regulation mechanisms are proposed.

  5. Dynamics of action potential initiation in the GABAergic thalamic reticular nucleus in vivo.

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    Fabián Muñoz

    Full Text Available Understanding the neural mechanisms of action potential generation is critical to establish the way neural circuits generate and coordinate activity. Accordingly, we investigated the dynamics of action potential initiation in the GABAergic thalamic reticular nucleus (TRN using in vivo intracellular recordings in cats in order to preserve anatomically-intact axo-dendritic distributions and naturally-occurring spatiotemporal patterns of synaptic activity in this structure that regulates the thalamic relay to neocortex. We found a wide operational range of voltage thresholds for action potentials, mostly due to intrinsic voltage-gated conductances and not synaptic activity driven by network oscillations. Varying levels of synchronous synaptic inputs produced fast rates of membrane potential depolarization preceding the action potential onset that were associated with lower thresholds and increased excitability, consistent with TRN neurons performing as coincidence detectors. On the other hand the presence of action potentials preceding any given spike was associated with more depolarized thresholds. The phase-plane trajectory of the action potential showed somato-dendritic propagation, but no obvious axon initial segment component, prominent in other neuronal classes and allegedly responsible for the high onset speed. Overall, our results suggest that TRN neurons could flexibly integrate synaptic inputs to discharge action potentials over wide voltage ranges, and perform as coincidence detectors and temporal integrators, supported by a dynamic action potential threshold.

  6. Fronto-thalamic volumetry markers of somatic delusions and hallucinations in schizophrenia.

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    Spalletta, Gianfranco; Piras, Fabrizio; Alex Rubino, Ivo; Caltagirone, Carlo; Fagioli, Sabrina

    2013-04-30

    Although the psychotic phenomena of schizophrenia have been extensively investigated, somatic delusions and hallucinations have seldom been reported and their mechanisms are substantially unexplored. Here, we aimed to identify the brain structural correlates of somatic psychotic phenomena using combined volumetry and diffusivity structural neuroimaging techniques. Seventy-five individuals with a DSM-IV-TR diagnosis of schizophrenia and 75 healthy controls (HC) underwent a comprehensive clinical assessment, a high-resolution T1-weighted magnetic resonance imaging and a diffusion tensor imaging protocol using a 3T MRI scanner. Voxel-based volumetry and mean diffusivity (MD) of gray matter (GM) and fractional anisotropy (FA) of white matter (WM) of the whole brain were calculated for each subject. Reduced left fronto-insular GM volume was found in patients with somatic delusions compared with patients without somatic delusions and HC. Increased GM volume was found in the bilateral thalami, primarily in the right ventral-anterior thalamic nucleus projecting to the prefrontal-temporal cortices and the bilateral pars triangularis of the inferior frontal lobe, of patients with somatic hallucinations and HC compared with patients without somatic hallucinations. No differences emerged in GM MD and in WM FA between patients with and without psychotic somatic phenomena (i.e. delusions or hallucinations). These findings provide the first evidence that a frontal-thalamic structural perturbation mediates somatic psychotic phenomena in schizophrenia.

  7. Effects of metabolites of the analgesic agent dipyrone (metamizol) on rostral ventromedial medulla cell activity in mice.

    Science.gov (United States)

    Maione, Sabatino; Radanova, Lilyana; De Gregorio, Danilo; Luongo, Livio; De Petrocellis, Luciano; Di Marzo, Vincenzo; Imming, Peter

    2015-02-05

    The molecular mechanism of action of dipyrone, a widely used antipyretic and non-opioid analgesic drug, is still not fully understood. Actions upon peripheral inflamed tissues as well as the central nervous system, especially upon the PAG-RVM axis, have been suggested. Dipyrone is a prodrug and its activity is due to its immediate conversion to its active metabolites. We tested the effect of two recently discovered metabolites of dipyrone, the arachidonoyl amides of 4-methylaminoantipyrine and 4-aminoantipyrine, on the neurons of the rostral ventromedial medulla (RVM), which are part of the descending pathway of antinociception. These compounds reduced the activity of ON-cells and increased the activity of OFF-cells. Both CB1 and TRPV1 blockade reversed these effects, suggesting that the endocannabinoid/endovanilloid system takes part in the analgesic effects of dipyrone. Copyright © 2015. Published by Elsevier B.V.

  8. The coelacanth rostral organ is a unique low-resolution electro-detector that facilitates the feeding strike.

    Science.gov (United States)

    Berquist, Rachel M; Galinsky, Vitaly L; Kajiura, Stephen M; Frank, Lawrence R

    2015-03-11

    The cartilaginous and non-neopterygian bony fishes have an electric sense typically comprised of hundreds or thousands of sensory canals distributed in broad clusters over the head. This morphology facilitates neural encoding of local electric field intensity, orientation, and polarity, used for determining the position of nearby prey. The coelacanth rostral organ electric sense, however, is unique in having only three paired sensory canals with distribution restricted to the dorsal snout, raising questions about its function. To address this, we employed magnetic resonance imaging methods to map electrosensory canal morphology in the extant coelacanth, Latimeria chalumnae, and a simple dipole 'rabbit ears' antennae model with toroidal gain function to approximate their directional sensitivity. This identified a unique focal region of electrosensitivity directly in front of the mouth, and is the first evidence of a low-resolution electro-detector that solely facilitates prey ingestion.

  9. Different cardiovascular neuron groups in the ventral reticular formation of the rostral medulla in rabbits: single neurone studies.

    Science.gov (United States)

    Kishi, E; Ootsuka, Y; Terui, N

    2000-03-15

    To examine whether the cardiovascular neurons of the ventral medulla consist of functionally different kinds of neurons, single neuronal activity of the ventral medulla, activity of the renal sympathetic nerves (RSNA), blood flow of the ear (EarBF) and arterial pressure (AP) were recorded in urethane-anesthetized, vagotomized and immobilized rabbits during electrical stimulation of the aortic nerve (AN, baroreceptor afferent fibers) and electrical stimulation of the dorsomedial hypothalamus (DMH) that reduced EarBF but less affected on AP and RSNA. The dorsolateral funiculus of the second cervical cord was stimulated to evoke antidromic spikes of medullary neurons. Two kinds of reticulo-spinal neurons were identified. Activities of one kind of neurons were facilitated by stimulation of DMH (latency 48.6+/-27.6 ms, n=11) but they did not respond to stimulation of the AN. Therefore, it was presumed that these neurons controlled vasomotion of the ear through the vasoconstrictor neurons in the spinal cord but did not participate in regulation of systemic AP. Activities of the other neurons were inhibited by stimulation of the AN (latency 47.8+/-8 4 ms, n=16) but they did not respond to the DMH stimulation. These neurons were identical to those reported previously as the RVLM neurons, and they contributed to regulate systemic AP but might not participate in control of cutaneous vascular movement. The former neurons were located medially to the latter in the reticular formation of the rostral ventral medulla. These results provided evidence at the single neuronal level that the cardiovascular neurons in the ventral medulla were consisted of functionally different sympatho-excitatory neurons and they were located at the different sites in the rostral ventral medulla.

  10. Characteristics of rostral solitary tract nucleus neurons with identified afferent connections that project to the parabrachial nucleus in rats.

    Science.gov (United States)

    Suwabe, Takeshi; Bradley, Robert M

    2009-07-01

    Afferent information derived from oral chemoreceptors is transmitted to second-order neurons in the rostral solitary tract nucleus (rNST) and then relayed to other CNS locations responsible for complex sensory and motor behaviors. Here we investigate the characteristics of rNST neurons sending information rostrally to the parabrachial nucleus (PBN). Afferent connections to these rNST-PBN projection neurons were identified by anterograde labeling of the chorda tympani (CT), glossopharyngeal (IX), and lingual (LV) nerves. We used voltage- and current-clamp recordings in brain slices to characterize the expression of both the transient A-type potassium current, IKA and the hyperpolarization-activated inward current, Ih, important determinants of neuronal repetitive discharge characteristics. The majority of rNST-PBN neurons express IKA, and these IKA-expressing neurons predominate in CT and IX terminal fields but were expressed in approximately half of the neurons in the LV field. rNST-PBN neurons expressing Ih were evenly distributed among CT, IX and LV terminal fields. However, expression patterns of IKA and Ih differed among CT, IX, and LV fields. IKA-expressing neurons frequently coexpress Ih in CT and IX terminal fields, whereas neurons in LV terminal field often express only Ih. After GABAA receptor block all rNST-PBN neurons responded to afferent stimulation with all-or-none excitatory synaptic responses. rNST-PBN neurons had either multipolar or elongate morphologies and were distributed throughout the rNST, but multipolar neurons were more often encountered in CT and IX terminal fields. No correlation was found between the biophysical and morphological characteristics of the rNST-PBN projection neurons in each terminal field.

  11. May Functional Imaging be Helpful for Behavioral Assessment in Children? Regions of Motor and Associative Cortico-Subcortical Circuits Can be Differentiated by Laterality and Rostrality.

    Science.gov (United States)

    August, Julia M; Rothenberger, Aribert; Baudewig, Juergen; Roessner, Veit; Dechent, Peter

    2015-01-01

    Cortico-subcortical circuits are organized into the sensorimotor, associative, and limbic loop. These neuronal preconditions play an important role regarding the understanding and treatment of behavioral problems in children. Differencing evidence argues for a lateralized organization of the sensorimotor loop and a bilateral (i.e., non-lateralized) organization of the associative loop. However, a firm behavioral-neurobiological distinction of these circuits has been difficult, specifically in children. Thus, the aim was a comprehensive functional visualization and differentiation of the sensorimotor and the associative circuit during childhood. As a new approach, laterality and rostrality features were used to distinguish between the two circuits within one single motor task. Twenty-four healthy boys performed self-paced index finger tapping with each hand separately during functional magnetic resonance imaging at 3 Tesla. A contrast analysis for left against right hand movement revealed lateralized activation in typical sensorimotor regions such as primary sensorimotor cortex, caudal supplementary motor area (SMA), caudal putamen, and thalamus. A conjunction analysis confirmed bilateral involvement of known associative regions including pre-SMA, rostral SMA, and rostral putamen. A functional visualization of two distinct corticostriatal circuits is provided in childhood. Both the sensorimotor and associative circuit may be discriminated by their laterality characteristics already in minors. Additionally, the results support the concept of a modified functional subdivision of the SMA in a rostral (associative) and caudal (motor) part. A further development of this approach might help to nurture behavioral assessment and neurofeedback training in child mental health.

  12. Remedial action and feedback processing in a time-estimation task: Evidence for a role of the rostral cingulate zone in behavioral adjustments without learning

    NARCIS (Netherlands)

    Veen, F.M. van der; Röder, C.H.; Mies, G.W.; Lugt, A. van der; Smits, M.

    2011-01-01

    The present study examined the role of the rostral cingulate zone (RCZ) in feedback processing, and especially focused on effects of modality of the feedback stimulus and remedial action. Participants performed a time-estimation task in which they had to estimate a 1-second interval. After the estim

  13. Effect of spinal manipulation thrust duration on trunk mechanical activation thresholds of nociceptive-specific lateral thalamic neurons.

    Science.gov (United States)

    Reed, William R; Sozio, Randall; Pickar, Joel G; Onifer, Stephen M

    2014-10-01

    The objective of this preliminary study was to determine if high-velocity, low-amplitude spinal manipulation (HVLA-SM) thrust duration alters mechanical trunk activation thresholds of nociceptive-specific (NS) lateral thalamic neurons. Extracellular recordings were obtained from 18 NS neurons located in 2 lateral thalamic nuclei (ventrolateral [n = 12] and posterior [n = 6]) in normal anesthetized Wistar rats. Response thresholds to electronic von Frey anesthesiometer (rigid tip) mechanical trunk stimuli applied in 3 lumbar directions (dorsal-ventral, 45° caudal, and 45° cranial) were determined before and immediately after the delivery of 3 HVLA-SM thrust durations (time control 0, 100, and 400 milliseconds). Mean changes in mechanical trunk activation thresholds were compared using a mixed model analysis of variance. High-velocity, low-amplitude spinal manipulation duration did not significantly alter NS lateral thalamic neurons' mechanical trunk responses to any of the 3 directions tested with the anesthesiometer. This study is the first to examine the effect of HVLA-SM thrust duration on NS lateral thalamic mechanical response thresholds. High-velocity, low-amplitude spinal manipulation thrust duration did not affect mechanical trunk thresholds. Copyright © 2014 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

  14. Functional characterization and expression of thalamic GABA(B) receptors in a rodent model of Parkinson's disease

    NARCIS (Netherlands)

    de Groote, C; Wullner, U; Loschmann, PA; Luiten, PGM; Klockgether, T

    1999-01-01

    Increased GABAergic neurotransmission of the basal ganglia output nuclei projecting to the motor thalamus is thought to contribute to the pathophysiology of Parkinson's disease. We investigated the functional role of thalamic GABA(B) receptors in a rodent model of Parkinson's disease. First, we exam

  15. MM2-thalamic Creutzfeldt-Jakob disease: neuropathological, biochemical and transmission studies identify a distinctive prion strain.

    Science.gov (United States)

    Moda, Fabio; Suardi, Silvia; Di Fede, Giuseppe; Indaco, Antonio; Limido, Lucia; Vimercati, Chiara; Ruggerone, Margherita; Campagnani, Ilaria; Langeveld, Jan; Terruzzi, Alessandro; Brambilla, Antonio; Zerbi, Pietro; Fociani, Paolo; Bishop, Matthew T; Will, Robert G; Manson, Jean C; Giaccone, Giorgio; Tagliavini, Fabrizio

    2012-09-01

    In Creutzfeldt-Jakob disease (CJD), molecular typing based on the size of the protease resistant core of the disease-associated prion protein (PrP(Sc) ) and the M/V polymorphism at codon 129 of the PRNP gene correlates with the clinico-pathologic subtypes. Approximately 95% of the sporadic 129MM CJD patients are characterized by cerebral deposition of type 1 PrP(Sc) and correspond to the classic clinical CJD phenotype. The rare 129MM CJD patients with type 2 PrP(Sc) are further subdivided in a cortical and a thalamic form also indicated as sporadic fatal insomnia. We observed two young patients with MM2-thalamic CJD. Main neuropathological features were diffuse, synaptic PrP immunoreactivity in the cerebral cortex and severe neuronal loss and gliosis in the thalamus and olivary nucleus. Western blot analysis showed the presence of type 2A PrP(Sc) . Challenge of transgenic mice expressing 129MM human PrP showed that MM2-thalamic sporadic CJD (sCJD) was able to transmit the disease, at variance with MM2-cortical sCJD. The affected mice showed deposition of type 2A PrP(Sc) , a scenario that is unprecedented in this mouse line. These data indicate that MM2-thalamic sCJD is caused by a prion strain distinct from the other sCJD subtypes including the MM2-cortical form. © 2012 The Authors; Brain Pathology © 2012 International Society of Neuropathology.

  16. Crossed cerebellar diaschisis in acute isolated thalamic infarction detected by dynamic susceptibility contrast perfusion MRI.

    Directory of Open Access Journals (Sweden)

    Alex Förster

    Full Text Available PURPOSE: Crossed cerebellar diaschisis (CCD is a state of neural depression caused by loss of connections to injured neural structures remote from the cerebellum usually evaluated by positron emission tomography. Recently it has been shown that dynamic susceptibility contrast perfusion weighted MRI (PWI may also be feasible to detect the phenomenon. In this study we aimed to assess the frequency of CCD on PWI in patients with acute thalamic infarction. METHODS: From a MRI report database we identified patients with acute isolated thalamic infarction. Contralateral cerebellar hypoperfusion was identified by inspection of time to peak (TTP maps and evaluated quantitatively on TTP, mean transit time (MTT, cerebral blood flow and volume (CBF, CBV maps. A competing cerebellar pathology or an underlying vascular pathology were excluded. RESULTS: A total of 39 patients was included. Common symptoms were hemiparesis (53.8%, hemihypaesthesia (38.5%, dysarthria (30.8%, aphasia (17.9%, and ataxia (15.4%. In 9 patients (23.1% PWI showed hypoperfusion in the contralateral cerebellar hemisphere. All of these had lesions in the territory of the tuberothalamic, paramedian, or inferolateral arteries. Dysarthria was observed more frequently in patients with CCD (6/9 vs. 6/30; OR 8.00; 95%CI 1.54-41.64, p = 0.01. In patients with CCD, the median ischemic lesion volume on DWI (0.91 cm³, IQR 0.49-1.54 cm³ was larger compared to patients with unremarkable PWI (0.51 cm³, IQR 0.32-0.74, p = 0.05. The most pronounced changes were found in CBF (0.94±0.11 and MTT (1.06±0.13 signal ratios, followed by TTP (1.05±0.02. CONCLUSIONS: Multimodal MRI demonstrates CCD in about 20% of acute isolated thalamic infarction patients. Lesion size seems to be a relevant factor in its pathophysiology.

  17. Medial thalamic 18-FDG uptake following inescapable shock correlates with subsequent learned helpless behavior

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    Mirrione,M.M.; Mirrione, M.M.; Schulz, D.; Dewey, S.L.; Henn, F.A.

    2009-12-06

    The learned helplessness paradigm has been repeatedly shown to correlate with neurobiological aspects of depression in humans. In this model, rodents are exposed inescapable foot-shock in order to reveal susceptibility to escape deficit, defined as 'learned helplessness' (LH). Few methods are available to probe the neurobiological aspects underlying the differences in susceptibility in the living animal, thus far being limited to studies examining regional neurochemical changes with microdialysis. With the widespread implementation of small animal neuroimaging methods, including positron emission tomography (PET), it is now possible to explore the living brain on a systems level to define regional changes that may correlate with vulnerability to stress. In this study, 12 wild type Sprague-Dawley rats were exposed to 40 minutes of inescapable foot-shock followed by metabolic imaging using 2-deoxy-2[{sup 18}F]fluoro-D-glucose (18-FDG) 1 hour later. The escape test was performed on these rats 48 hours later (to accommodate radiotracer decay), where they were given the opportunity to press a lever to shut off the shock. A region of interest (ROI) analysis was used to investigate potential correlations (Pearson Regression Coefficients) between regional 18-FDG uptake following inescapable shock and subsequent learned helpless behavior (time to finish the test; number of successful lever presses within 20 seconds of shock onset). ROI analysis revealed a significant positive correlation between time to finish and 18-FDG uptake, and a negative correlation between lever presses and uptake, in the medial thalamic area (p=0.033, p=0.036). This ROI included the paraventricular thalamus, mediodorsal thalamus, and the habenula. In an effort to account for possible spillover artifact, the posterior thalamic area (including ventral medial and lateral portions) was also evaluated but did not reveal significant correlations (p=0.870, p=0.897). No other significant

  18. Altered cortico-striatal-thalamic connectivity in relation to spatial working memory capacity in children with ADHD

    Directory of Open Access Journals (Sweden)

    Kathryn L. Mills

    2012-01-01

    Full Text Available Introduction: Attention deficit hyperactivity disorder (ADHD captures a heterogeneous group of children, who are characterized by a range of cognitive and behavioral symptoms. Previous resting state functional connectivity (rs-fcMRI studies have sought to understand the neural correlates of ADHD by comparing connectivity measurements between those with and without the disorder, focusing primarily on cortical-striatal circuits mediated by the thalamus. To integrate the multiple phenotypic features associated with ADHD and help resolve its heterogeneity, it is helpful to determine how specific circuits relate to unique cognitive domains of the ADHD syndrome. Spatial working memory has been proposed as a key mechanism in the pathophysiology of ADHD.Methods: We correlated the rs-fcMRI of five thalamic regions of interest with spatial span working memory scores in a sample of 67 children aged 7-11 years (ADHD and typically developing children; TDC. In an independent dataset, we then examined group differences in thalamo-striatal functional connectivity between 70 ADHD and 89 TDC (7-11 years from the ADHD-200 dataset. Thalamic regions of interest were created based on previous methods that utilize known thalamo-cortical loops and rs-fcMRI to identify functional boundaries in the thalamus.Results/Conclusions: Using these thalamic regions, we found atypical rs-fcMRI between specific thalamic groupings with the basal ganglia. To identify the thalamic connections that relate to spatial working memory in ADHD, only connections identified in both the correlational and comparative analyses were considered. Multiple connections between the thalamus and basal ganglia, particularly between medial and anterior dorsal thalamus and the putamen, were related to spatial working memory and also altered in ADHD. These thalamo-striatal disruptions may be one of multiple atypical neural and cognitive mechanisms that relate to the ADHD clinical phenotype.

  19. Excitatory amino acid transporter 2 downregulation correlates with thalamic neuronal death following kainic acid-induced status epilepticus in rat.

    Science.gov (United States)

    Sakurai, Masashi; Kurokawa, Haruna; Shimada, Akinori; Nakamura, Kazuhiro; Miyata, Hajime; Morita, Takehito

    2015-02-01

    Recurrent seizures without interictal resumption (status epilepticus) have been reported to induce neuronal death in the midline thalamic region that has functional roles in memory and decision-making; however, the pathogenesis underlying status epilepticus-induced thalamic neuronal death is yet to be determined. We performed histological and immunohistochemical studies as well as cerebral blood flow measurement using 4.7 tesla magnetic resonance imaging spectrometer on midline thalamic region in Sprague-Dawley rats (n = 75, male, 7 weeks after birth, body weight 250-300 g) treated with intraperitoneal injection of kainic acid (10 mg/kg) to induce status epilepticus (n = 55) or normal saline solution (n = 20). Histological study using paraffin-embedded specimens revealed neuronal death showing ischemic-like changes and Fluoro-Jade C positivity with calcium deposition in the midline thalamic region of epileptic rats. The distribution of neuronal death was associated with focal loss of immunoreactivity for excitatory amino acid transporter 2 (EAAT2), stronger immunoreaction for glutamate and increase in number of Iba-1-positive microglial cells showing swollen cytoplasm and long processes. Double immunofluorescence study demonstrated co-expression of interleukin-1 beta (IL-1β) and inducible nitric oxide synthase (iNOS) within microglial cells, and loss of EAAT2 immunoreactivity in reactive astrocytes. These microglial alterations and astrocytic EAAT2 downregulation were also observed in tissue without obvious neuronal death in kainic acid-treated rats. These results suggest the possible role of glutamate excitotoxicity in neuronal death in the midline thalamic region following kainic acid-induced status epilepticus due to astrocytic EAAT2 downregulation following microglial activation showing upregulation of IL-1β and iNOS.

  20. The findings of Tc-99m ECD brain perfusion SPECT in the patients with left anterior thalamic infarction

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Y. A.; Kim, S. H.; Sohn, H. S.; Jeong, S. G. [The Catholic University of Korea, Seoul (Korea, Republic of)

    2005-07-01

    The thalamus has multiple connections with areas of the cerebral cortex involved in arousal and cognition. Thalamic damage has been reported to be associated with variable neuropsychological dysfunctions and dementia. This study evaluates the changes of regional cerebral blood flow (rCBF) by using SPM analysis of brain perfusion SPECT and examining the neuropsychological abnormalities of 4 patients with anterior thalamic infarctions. Four patients with left anterior thalamic infarctions and eleven normal controls were evaluated. K-MMSE and the Seoul Neuropsychological Screening Battery were performed within 2 days after stroke. The normalized SPECT data of 4 patients were compared to those of 11 controls for the detection of areas with decreased rCBF by SPM analysis. All 4 patients showed anterograde amnesia in their verbal memory, which was not improved by recognition. Dysexecutive features were occasionally present, such as decreased word fluency and impaired Stroop test results. SPM analysis revealed decreased rCBF in the left supra marginal gyrus, the superior temporal gyrus, the middle and inferior frontal gyrus, the medial dorsal and anterior nucleus of the left thalamus. The changes of rCBF in patients with left anterior thalamic infarctions may be due to the remote suppression on metabolism by the interruption of the cortico-subcortical circuit, which connects the anterior thalamic nucleus and various cortical areas. The executive dysfunction and dysnomia may be caused by the left dorsolateral frontal dysfunction of the thalamo-cortical circuit. Anterograde amnesia with storage deficit may be caused by the disruption of mamillothalamic tract.

  1. Thalamic contributions to anterograde, retrograde, and implicit memory: a case study.

    Science.gov (United States)

    Hampstead, Benjamin M; Koffler, Sandra P

    2009-09-01

    Learning and memory deficits are typically associated with damage or dysfunction of medial temporal lobe structures; however, diencephalic lesions are another common cause of severe and persistent memory deficits. We focus specifically on the thalamus and review the pathological and neuropsychological characteristics of two common causes of such damage: Korsakoff's syndrome and stroke. We then present a patient who had sustained bilateral medial thalamic infarctions that affected the medial dorsal nucleus and internal medullary lamina. This patient demonstrated the characteristic temporally graded retrograde amnesia and a profound anterograde memory (i.e., explicit memory) deficit within the context of relatively preserved implicit memory. Implications of this explicit-implicit discrepancy are discussed within the context of cognitive rehabilitation techniques that hold promise for more severely impaired patients.

  2. Acquired aphasia in children after surgical resection of left-thalamic tumors.

    Science.gov (United States)

    Nass, R; Boyce, L; Leventhal, F; Levine, B; Allen, J; Maxfield, C; Salsberg, D; Sarno, M; George, A

    2000-09-01

    Five children (three males, two females; four right-, one left-handed; age range 6 to 14 years) who developed aphasia after gross-total excision of left predominantly thalamic tumors are reported. Three patients had Broca aphasia, one had mixed transcortical aphasia, and one patient had conduction aphasia. In the months after surgery, three children improved while receiving radiation and/or chemotherapy, although none recovered completely. Two patients with malignant tumors developed worsening aphasia when the tumor recurred, and later died. Two of three patients tested had visuospatial difficulties in addition to language deficits. Attention and executive functioning were affected in three of three patients tested. Memory, verbal and/or visual functioning, were affected in four of four patients tested. Both patients who were tested showed transient right hemineglect. Two of two patients tested were probably apraxic. The wide range of deficits in these children highlights the importance of the thalamus and other subcortical structures in developing cognition.

  3. EFFECTS OF METHAMPHETAMINE ON LOCOMOTOR ACTIVITY AND THALAMIC GENE EXPRESSION IN LEPTIN-DEFICIENT OBESE MICE

    Science.gov (United States)

    González, Betina; González, Candela; Bisagno, Verónica; Urbano, Francisco J.

    2017-01-01

    Leptin is an adipose-derived hormone that regulates energy balance. Leptin receptors are expressed in extrahypothalamic sites and several reports showed that leptin can influence feeding and locomotor behavior via direct actions on dopaminergic neurons. The leptin deficient mouse (ob/ob) has been used as an animal model of blunted leptin action, and presents with obesity and mild type 2 diabetes. We used ob/ob mice to study the effect of repeated 7-day methamphetamine (METH) administration analyzing locomotion, behavioral sensitization, and somatosensory thalamic mRNA expression of voltage-gated calcium channels and glutamatergic receptors using RT-PCR. We observed reduced METH-mediated responses in ob/ob mice associated with enhanced in mRNA expression of key voltage-gated and glutamate receptors in the somatosensory thalamus. Results described here are important for understanding the control of locomotion and thalamocortical excitability by leptin.

  4. Bilateral symmetrical basal ganglia and thalamic lesions in children: an update (2015)

    Energy Technology Data Exchange (ETDEWEB)

    Zuccoli, Giulio [Children' s Hospital of Pittsburgh of UPMC, Section of Neuroradiology, Pittsburgh, PA (United States); Yannes, Michael Paul [University of Pittsburgh School of Medicine, Department of Radiology, Pittsburgh, PA (United States); Nardone, Raffaele [Paracelsus Medical University, Department of Neurology, Christian Doppler Klinik, Salzburg (Austria); Bailey, Ariel [West Virginia University, Department of Radiology, Morgantown, WV (United States); Goldstein, Amy [Children' s Hospital of Pittsburgh of UPMC, Department of Neurology, Section of Metabolic Disorders and Neurogenetics, Pittsburgh, PA (United States)

    2015-10-15

    In children, many inherited or acquired neurological disorders may cause bilateral symmetrical signal intensity alterations in the basal ganglia and thalami. A literature review was aimed at assisting neuroradiologists, neurologists, infectious diseases specialists, and pediatricians to provide further understanding into the clinical and neuroimaging features in pediatric patients presenting with bilateral symmetrical basal ganglia and thalamic lesions on magnetic resonance imaging (MRI). We discuss hypoxic-ischemic, toxic, infectious, immune-mediated, mitochondrial, metabolic, and neurodegenerative disorders affecting the basal ganglia and thalami. Recognition and correct evaluation of basal ganglia abnormalities, together with a proper neurological examination and laboratory findings, may enable the identification of each of these clinical entities and lead to earlier diagnosis. (orig.)

  5. [Persistent psychotic disorder following bilateral mesencephalo-thalamic ischaemia: case report].

    Science.gov (United States)

    Predescu, A; Damsa, C; Riegert, M; Bumb, A; Pull, C

    2004-01-01

    A 38-year old male patient with no history of psychiatric illness developed a progressive psychotic disorder after bilateral (predominantly left) mesencephalo-thalamic cerebral ischaemia. The reason of the emergency hospitalization was the sudden onset of a confusional state, culminating in a fluctuating comatose status. The neurological examination found mild right hemiparesia, praxic disorders and reactive left mydriasis with paresia of the downward vertical stare, leading to the hospitalisation in the neurology department for suspicion of a cerebral vascular ischaemic accident. The psychiatric symptoms started with acoustic-verbal hallucinations, poorly structured paranoid delusions, progressively developed over two weeks, followed by behavioural disorders with psychomotor agitation and heteroaggressivity. The patient was transferred to the psychiatric department, because of the heteroaggressive risk and lack of morbid consciousness, in spite of recovering from the confusional status. An intensive psychiatric management was proposed, combining a psychotherapeutic approach with 4 mg of risperidone and adjustable doses of benzodiazepine according to the psychomotor agitation. During the next days, there was a net recovery of the behavioural disorders, in spite of the persistence of the ideas of persecution. All the neurological symptoms also decreased. An anomaly of the polygon of Willis was found on a cerebral arteriography (the posterior cerebral arteries had a foetal origin, dependent on carotidal axes and not on the vertebro-basilar system). The main emboligen risk factor was the presence of a permeable foramen ovale, discovered during a transoesophageal echography. The patient underwent a surgical correction of the permeable foramen ovale. The psychiatric hospitalization for three months was continued by ambulatory follow-up. The initial positive symptoms (delusions, acoustic-verbal hallucinations) progressively diminished while negative symptoms became

  6. Strategic lesions in the anterior thalamic radiation and apathy in early Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Mario Torso

    Full Text Available Behavioural disorders and psychological symptoms of Dementia (BPSD are commonly observed in Alzheimer's disease (AD, and strongly contribute to increasing patients' disability. Using voxel-lesion-symptom mapping (VLSM, we investigated the impact of white matter lesions (WMLs on the severity of BPSD in patients with amnestic mild cognitive impairment (a-MCI.Thirty-one a-MCI patients (with a conversion rate to AD of 32% at 2 year follow-up and 26 healthy controls underwent magnetic resonance imaging (MRI examination at 3T, including T2-weighted and fluid-attenuated-inversion-recovery images, and T1-weighted volumes. In the patient group, BPSD was assessed using the Neuropsychiatric Inventory-12. After quantitative definition of WMLs, their distribution was investigated, without an a priori anatomical hypothesis, against patients' behavioural symptoms. Unbiased regional grey matter volumetrics was also used to assess the contribution of grey matter atrophy to BPSD.Apathy, irritability, depression/dysphoria, anxiety and agitation were shown to be the most common symptoms in the patient sample. Despite a more widespread anatomical distribution, a-MCI patients did not differ from controls in WML volumes. VLSM revealed a strict association between the presence of lesions in the anterior thalamic radiations (ATRs and the severity of apathy. Regional grey matter atrophy did not account for any BPSD.This study indicates that damage to the ATRs is strategic for the occurrence of apathy in patients with a-MCI. Disconnection between the prefrontal cortex and the mediodorsal and anterior thalamic nuclei might represent the pathophysiological substrate for apathy, which is one of the most common psychopathological symptoms observed in dementia.

  7. Two classes of excitatory synaptic responses in rat thalamic reticular neurons.

    Science.gov (United States)

    Deleuze, Charlotte; Huguenard, John R

    2016-09-01

    The thalamic reticular nucleus (nRt), composed of GABAergic cells providing inhibition of relay neurons in the dorsal thalamus, receives excitation from the neocortex and thalamus. The two excitatory pathways promoting feedback or feedforward inhibition of thalamocortical neurons contribute to sensory processing and rhythm generation. While synaptic inhibition within the nRt has been carefully characterized, little is known regarding the biophysics of synaptic excitation. To characterize the functional properties of thalamocortical and corticothalamic connections to the nRt, we recorded minimal electrically evoked excitatory postsynaptic currents from nRt cells in vitro. A hierarchical clustering algorithm distinguished two types of events. Type 1 events had larger amplitudes and faster kinetics, largely mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, whereas type 2 responses had more prominent N-methyl-d-aspartate (NMDA) receptor contribution. Type 1 responses showed subnormal axonal propagation and paired pulse depression, consistent with thalamocortical inputs. Furthermore, responses kinetically similar to type 1 events were evoked by glutamate-mediated activation of thalamic neurons. Type 2 responses, in contrast, likely arise from corticothalamic inputs, with larger NMDA conductance and weak Mg(2+)-dependent block, suggesting that NMDA receptors are critical for the cortical excitation of reticular neurons. The long-lasting action of NMDA receptors would promote reticular cell burst firing and produce powerful inhibitory output to relay neurons proposed to be important in triggering epilepsy. This work provides the first complete voltage-clamp analysis of the kinetics and voltage dependence of AMPA and NMDA responses of thalamocortical and corticothalamic synapses in the nRt and will be critical in optimizing biologically realistic neural network models of thalamocortical circuits relevant to sensory processing and

  8. Thalamic metabolic abnormalities in patients with Huntington's disease measured by magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Casseb, R.F.; Castellano, G., E-mail: gabriela@ifi.unicamp.br [Cooperacao Interinstitucional de Apoio a Pesquisas sobre o Cerebro (Programa CInAPCe), Sao Paulo, SP (Brazil); Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin. Dept. de Raios Cosmicos e Cronologia; D' Abreu, A.; Cendes, F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Dept. de Neurologia. Lab. de Neuroimagem; Cooperacao Interinstitucional de Apoio a Pesquisas sobre o Cerebro (Programa CInAPCe), Sao Paulo, SP (Brazil); Ruocco, H.H. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Ciencias Medicas. Dept. de Neurologia. Lab. de Neuroimagem; Lopes-Cendes, I., E-mail: seixas.fk@gmail.com [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Ciencias Medicas. Dept. de Genetica Medica; Cooperacao Interinstitucional de Apoio a Pesquisas sobre o Cerebro (Programa CInAPCe), Sao Paulo, SP (Brazil)

    2013-08-15

    Huntington's disease (HD) is a neurologic disorder that is not completely understood; its fundamental physiological mechanisms and chemical effects remain somewhat unclear. Among these uncertainties, we can highlight information about the concentrations of brain metabolites, which have been widely discussed. Concentration differences in affected, compared to healthy, individuals could lead to the development of useful tools for evaluating the progression of disease, or to the advance of investigations of different/alternative treatments. The aim of this study was to compare the thalamic concentration of metabolites in HD patients and healthy individuals using magnetic resonance spectroscopy. We used a 2.0-Tesla magnetic field, repetition time of 1500 ms, and echo time of 135 ms. Spectra from 40 adult HD patients and 26 control subjects were compared. Quantitative analysis was performed using the LCModel method. There were statistically significant differences between HD patients and controls in the concentrations of N-acetylaspartate+N-acetylaspartylglutamate (NAA+NAAG; t-test, P,0.001), and glycerophosphocholine+phosphocholine (GPC+PCh; t-test, P=0.001) relative to creatine+phosphocreatine (Cr+PCr). The NAA+NAAG/Cr+PCr ratio was decreased by 9% and GPC+PCh/Cr+PCr increased by 17% in patients compared with controls. There were no correlations between the concentration ratios and clinical features. Although these results could be caused by T1 and T2 changes, rather than variations in metabolite concentrations given the short repetition time and long echo time values used, our findings point to thalamic dysfunction, corroborating prior evidence. (author)

  9. Mediodorsal and Visual Thalamic Connectivity Differ in Schizophrenia and Bipolar Disorder With and Without Psychosis History

    Science.gov (United States)

    Anticevic, Alan; Yang, Genevieve; Savic, Aleksandar; Murray, John D.; Cole, Michael W.; Repovs, Grega; Pearlson, Godfrey D.; Glahn, David C.

    2014-01-01

    Empirical and theoretical studies implicate thalamocortical circuits in schizophrenia, supported by emerging resting-state functional connectivity studies (rs-fcMRI). Similar but attenuated alterations were found in bipolar disorder (BD). However, it remains unknown if segregated loops within thalamocortical systems show distinct rs-fcMRI alterations in schizophrenia. For instance, the mediodorsal (MD) nucleus, known to project to prefrontal networks, may be differently altered than the lateral geniculate nucleus (LGN), known to project to the occipital cortex. Also, it remains unknown if these circuits show different patterns of alterations in BD as a function of psychosis history, which may be associated with a more severe clinical course. We addressed these questions in 90 patients with chronic schizophrenia and 73 remitted BD patients (33 with psychosis history) matched to 146 healthy comparison subjects. We hypothesized that the MD vs LGN would show dissociations across diagnostic groups. We found that MD and LGN show more qualitative similarities than differences in their patterns of dysconnectivity in schizophrenia. In BD, patterns qualitatively diverged between thalamic nuclei although these effects were modest statistically. BD with psychosis history was associated with more severe dysconnectivity, particularly for the MD nucleus. Also, the MD nucleus showed connectivity reductions with the cerebellum in schizophrenia but not in BD. Results suggest dissociations for thalamic nuclei across diagnoses, albeit carefully controlling for medication is warranted in future studies. Collectively, these findings have implications for designing more precise neuroimaging-driven biomarkers that can identify common and divergent large-scale network perturbations across psychiatric diagnoses with shared symptoms. PMID:25031221

  10. CT classification of small thalamic hemorrhages. Topographic localization and clinical manifestation

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, Nobutaka; Kaneko, Mitsuo; Tanaka, Keisei; Muraki, Masaaki; Sato, Kengo (Hamamatsu Medical Center Hospital, Shizuoka (Japan))

    1984-06-01

    The thalamus is located deep in the cerebral hemispheres, and most of its nuclei have reciprocal fiber connections with specific areas over the cerebral cortex. Localized lesions in the thalamus, therefore, can cause specific neurological deficits, depending on their locations. From this point of view, we reviewed 110 cases, admitted over the past 7 years, with thalamic hemorrhages 37 (34%) of which were small hematomas less than 2 cm in diameter. These small hematomas could be divided into 4 types depending on their locations as follows: antero-lateral type, postero-lateral type, medial type, and dorsal type. Each type had the peculiar clinical features described below: 1) Postero-lateral Type (PL type, 28 cases, 76%): The original symptom was a sudden onset of moderate to severe sensori-motor deficits in most cases. The patients were mostly alert or only slightly confused. 2) Antero-lateral Type (AL type, 4 cases, 11%): The patients of this type first presented with sensori-motor disturbance and prefrontal signs. Both were generally mild and often disappeared early. 3) Medial Type (M type, 3 cases, 8%): The main symptom at onset was either a disturbance of consciousness or dementia. 4) Dorsal Type (D type, 2 cases, 5%): One patient with a right thalamic hematoma of this type showed geographical agnosia and visuo-constructive apraxia. The other patient, with a left-sided hematoma, exhibited transient clumsiness of the right hand and mild dysphasia. In our experience, the above classification of small hematomas clearly delineated the clinical symptoms and neurological signs of the different types; therefore, the symptoms and signs in larger hematoma could be explained by a combination of those of each type.

  11. [The thalamic syndrome of Déjérine-Roussy. Prolegomenon].

    Science.gov (United States)

    De Smet, Y

    1986-01-01

    Predicted by Dejerine and Long in 1898 and formally described by Dejerine and Roussy in 1906, the "thalamic syndrome" corrected the wrong hypothesis of a capsular "sensory cross roads" suggested by Charcot after 1873 and supported in France during 25 years. Both established the "persistent frank organic hemianesthesia" (sensory-sensitive for Charcot, pure sensitive for Dejerine), namely that a sensory deficit, still severe after regression of the early hemiplegia, could be due to focal brain damage. At that time such a clinical concept was hardly acceptable because it opposed the classic greek philosophical idea that sensation and movement should not be separated. Moreover, intelligence was at that time looked as a four-stage process including sensation, imagination, intellect and memory. The very first step began with the "sensus communis", an anteroom-like where all the sensations simultaneously perceived were coordinated to ensure mind unity. This "sensus communis" was given many subcortical seats during the following centuries, such as the trigone (Herophilus), the ventricles (Founders of the Church, Soemmering), the pineal body (Descartes), the striate bodies (Willis) and, finally, the thalamus (Todd and Carpenter's "English theory"). The description by Meynert in 1871 of a transcapsular direct "sensory bundle" and the cases reported by Türck in 1859 of a sensory-sensitive hemianesthesia after a posterior capsular lesion (in fact, thalamo-capsulostriate) led Charcot to develop his theory after 1873. Owing to the new staining methods of Weigert and Marchi introduced around 1885, Dejerine showed in 1895 the route of the medial lemniscus and his arrival in the thalamus, which led him to postulate in 1898 a "thalamic syndrome" and later to demonstrate it.

  12. Prolonged hyperpolarizing potentials precede spindle oscillations in the thalamic reticular nucleus

    Science.gov (United States)

    Fuentealba, Pablo; Timofeev, Igor; Steriade, Mircea

    2004-01-01

    The thalamic reticular (RE) nucleus is a key structure in the generation of spindles, a hallmark bioelectrical oscillation during early stages of sleep. Intracellular recordings of RE neurons in vivo revealed the presence of prolonged hyperpolarizing potentials preceding spindles in a subgroup (30%) of neurons. These hyperpolarizations (6-10 mV) lasted for 200-300 ms and were present just before the onset of spontaneously occurring spindle waves. Corticothalamic volleys also were effective in generating such hyperpolarizations followed by spindles in RE neurons. A drop of up to 40% in the apparent input resistance (Rin) was associated with these hyperpolarizing potentials, suggesting an active process rather than disfacilitation. Accordingly, the reversal potential was approximately -100 mV for both spontaneous and cortically elicited hyperpolarizations, consistent with the activation of slow K+ conductances. QX-314 in the recording pipettes decreased both the amplitude and incidence of prolonged hyperpolarizations, suggesting the participation of G protein-dependent K+ currents in the generation of hyperpolarizations. Simultaneous extracellular and intracellular recordings in the RE nucleus demonstrated that some RE neurons discharged during the hyperpolarizations and, thus, may be implicated in their generation. The prolonged hyperpolarizations preceding spindles may play a role in the transition from tonic to bursting firing of RE neurons within a range of membrane potential (-60 to -65 mV) at which they set favorable conditions for the generation of low-threshold spike bursts that initiate spindle sequences. These data are further arguments for the generation of spindles within the thalamic RE nucleus. PMID:15210981

  13. Modulation of sensitivity to alcohol by cortical and thalamic brain regions.

    Science.gov (United States)

    Jaramillo, Anel A; Randall, Patrick A; Frisbee, Suzanne; Besheer, Joyce

    2016-10-01

    The nucleus accumbens core (AcbC) is a key brain region known to regulate the discriminative stimulus/interoceptive effects of alcohol. As such, the goal of the present work was to identify AcbC projection regions that may also modulate sensitivity to alcohol. Accordingly, AcbC afferent projections were identified in behaviorally naïve rats using a retrograde tracer which led to the focus on the medial prefrontal cortex (mPFC), insular cortex (IC) and rhomboid thalamic nucleus (Rh). Next, to examine the possible role of these brain regions in modulating sensitivity to alcohol, neuronal response to alcohol in rats trained to discriminate alcohol (1 g/kg, intragastric [IG]) vs. water was examined using a two-lever drug discrimination task. As such, rats were administered water or alcohol (1 g/kg, IG) and brain tissue was processed for c-Fos immunoreactivity (IR), a marker of neuronal activity. Alcohol decreased c-Fos IR in the mPFC, IC, Rh and AcbC. Lastly, site-specific pharmacological inactivation with muscimol + baclofen (GABAA agonist + GABAB agonist) was used to determine the functional role of the mPFC, IC and Rh in modulating the interoceptive effects of alcohol in rats trained to discriminate alcohol (1 g/kg, IG) vs. water. mPFC inactivation resulted in full substitution for the alcohol training dose, and IC and Rh inactivation produced partial alcohol-like effects, demonstrating the importance of these regions, with known projections to the AcbC, in modulating sensitivity to alcohol. Together, these data demonstrate a site of action of alcohol and the recruitment of cortical/thalamic regions in modulating sensitivity to the interoceptive effects of alcohol.

  14. Mediodorsal and visual thalamic connectivity differ in schizophrenia and bipolar disorder with and without psychosis history.

    Science.gov (United States)

    Anticevic, Alan; Yang, Genevieve; Savic, Aleksandar; Murray, John D; Cole, Michael W; Repovs, Grega; Pearlson, Godfrey D; Glahn, David C

    2014-11-01

    Empirical and theoretical studies implicate thalamocortical circuits in schizophrenia, supported by emerging resting-state functional connectivity studies (rs-fcMRI). Similar but attenuated alterations were found in bipolar disorder (BD). However, it remains unknown if segregated loops within thalamocortical systems show distinct rs-fcMRI alterations in schizophrenia. For instance, the mediodorsal (MD) nucleus, known to project to prefrontal networks, may be differently altered than the lateral geniculate nucleus (LGN), known to project to the occipital cortex. Also, it remains unknown if these circuits show different patterns of alterations in BD as a function of psychosis history, which may be associated with a more severe clinical course. We addressed these questions in 90 patients with chronic schizophrenia and 73 remitted BD patients (33 with psychosis history) matched to 146 healthy comparison subjects. We hypothesized that the MD vs LGN would show dissociations across diagnostic groups. We found that MD and LGN show more qualitative similarities than differences in their patterns of dysconnectivity in schizophrenia. In BD, patterns qualitatively diverged between thalamic nuclei although these effects were modest statistically. BD with psychosis history was associated with more severe dysconnectivity, particularly for the MD nucleus. Also, the MD nucleus showed connectivity reductions with the cerebellum in schizophrenia but not in BD. Results suggest dissociations for thalamic nuclei across diagnoses, albeit carefully controlling for medication is warranted in future studies. Collectively, these findings have implications for designing more precise neuroimaging-driven biomarkers that can identify common and divergent large-scale network perturbations across psychiatric diagnoses with shared symptoms. © The Author 2014. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please

  15. Inhibitory effects of microinjection of morphine into thalamic nucleus submedius on ipsilateral paw bee venom-induced inflammatory pain in the rat

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To examine whether microinjection of morphine into the rat thalamic nucleus submedius (Sm) could depress the bee venom (BV)-induced nociceptive behaviours. Methods In inflammatory pain model induced by BV subcutaneous injection into rat unilateral hind paw,the inhibitory effects of morphine microinjection into thalamic nucleus submedius (Sm) on the spontaneous nociceptive behavior,heat hyperalgesia and tactile allodynia,and the influence of naloxone on the morphine effects were observed in the rat...

  16. Neuroprotective role of heat shock protein 70 in the rostral ventrolateral medulla during acute mevinphos intoxication in the rat.

    Science.gov (United States)

    Chang, Chi; Chang, Alice Y W; Chan, Samuel H H

    2004-01-01

    Heat shock protein (HSP) is a family of highly conserved proteins that respond to stress and participate actively in cytoprotection. Within the HSP family, HSP70 is the major inducible member that confers protection against cell death. This study investigated whether HSP70 plays a neuroprotective role at the rostral ventrolateral medulla (RVLM), the origin of sympathetic neurogenic vasomotor tone in the medulla oblongata where the organophosphate insecticide mevinphos (Mev) acts to elicit cardiovascular toxicity. Experiments were carried out in adult male Sprague-Dawley rats that were maintained under propofol anesthesia. Intravenous administration of Mev (960 microg/kg) induced a significant increase in the HSP70 level in the ventrolateral medulla during phase I ('pro-life' phase), and returned to baseline during phase II ('pro-death' phase) Mev intoxication. Compared to artificial cerebrospinal fluid, normal mouse serum (1:20), or sense hsp70 oligonucleotide (50 pmol) pretreatment, microinjection of an anti-HSP70 antiserum (1:20) or an antisense hsp70 oligonucleotide (50 pmol) bilaterally into the RVLM significantly increased mortality, shortened the duration of phase I intoxication and augmented the induced hypotension in rats that received Mev (960 microg/ kg, i.v.). These results suggest that HSP70 induced in the RVLM during Mev intoxication provides neuroprotection against the organophosphate poison via prevention of cardiovascular depression.

  17. Rostral Agranular Insular Cortex Lesion with Motor Cortex Stimulation Enhances Pain Modulation Effect on Neuropathic Pain Model

    Directory of Open Access Journals (Sweden)

    Hyun Ho Jung

    2016-01-01

    Full Text Available It is well known that the insular cortex is involved in the processing of painful input. The aim of this study was to evaluate the pain modulation role of the insular cortex during motor cortex stimulation (MCS. After inducing neuropathic pain (NP rat models by the spared nerve injury method, we made a lesion on the rostral agranular insular cortex (RAIC unilaterally and compared behaviorally determined pain threshold and latency in 2 groups: Group A (NP + MCS; n=7 and Group B (NP + RAIC lesion + MCS; n=7. Also, we simultaneously recorded neuronal activity (NP; n=9 in the thalamus of the ventral posterolateral nucleus and RAIC to evaluate electrophysiological changes from MCS. The pain threshold and tolerance latency increased in Group A with “MCS on” and in Group B with or without “MCS on.” Moreover, its increase in Group B with “MCS on” was more than that of Group B without MCS or of Group A, suggesting that MCS and RAIC lesioning are involved in pain modulation. Compared with the “MCS off” condition, the “MCS on” induced significant threshold changes in an electrophysiological study. Our data suggest that the RAIC has its own pain modulation effect, which is influenced by MCS.

  18. Identification and characterization of neuroblasts in the subventricular zone and rostral migratory stream of the adult human brain

    Science.gov (United States)

    Wang, Congmin; Liu, Fang; Liu, Ying-Ying; Zhao, Cai-Hong; You, Yan; Wang, Lei; Zhang, Jingxiao; Wei, Bin; Ma, Tong; Zhang, Qiangqiang; Zhang, Yue; Chen, Rui; Song, Hongjun; Yang, Zhengang

    2011-01-01

    It is of great interest to identify new neurons in the adult human brain, but the persistence of neurogenesis in the subventricular zone (SVZ) and the existence of the rostral migratory stream (RMS)-like pathway in the adult human forebrain remain highly controversial. In the present study, we have described the general configuration of the RMS in adult monkey, fetal human and adult human brains. We provide evidence that neuroblasts exist continuously in the anterior ventral SVZ and RMS of the adult human brain. The neuroblasts appear singly or in pairs without forming chains; they exhibit migratory morphologies and co-express the immature neuronal markers doublecortin, polysialylated neural cell adhesion molecule and βIII-tubulin. Few of these neuroblasts appear to be actively proliferating in the anterior ventral SVZ but none in the RMS, indicating that neuroblasts distributed along the RMS are most likely derived from the ventral SVZ. Interestingly, no neuroblasts are found in the adult human olfactory bulb. Taken together, our data suggest that the SVZ maintains the ability to produce neuroblasts in the adult human brain. PMID:21577236

  19. Neurochemical properties of BDNF-containing neurons projecting to rostral ventromedial medulla in the ventrolateral periaqueductal gray

    Directory of Open Access Journals (Sweden)

    Jun-Bin eYin

    2014-11-01

    Full Text Available The periaqueductal gray (PAG modulates nociception via a descending pathway that relays in the rostral ventromedial medulla (RVM and terminates in the spinal cord. Previous behavioral pharmacology and electrophysiological evidence suggests that brain-derived neurotrophic factor (BDNF plays an important role in descending pain modulation, likely through the PAG-RVM pathway. However, there still lacks detailed information on the distribution of BDNF, activation of BDNF-containing neurons projecting to RVM in the condition of pain, and neurochemical properties of these neurons within the PAG. Through fluorescent in situ hybridization (FISH and immunofluorescent staining, the homogenous distributions of BDNF mRNA and protein were observed in the four subregions of PAG. Both neurons and astrocytes expressed BDNF, but not microglias. By combining retrograde tracing methods and formalin pain model, there were more BDNF-containing neurons projecting to RVM being activated in the ventrolateral PAG (vlPAG than other subregions of PAG. The neurochemical properties of BDNF-containing projection neurons in the vlPAG were investigated. BDNF-containing projection neurons expressed auto receptor Tropomyosin-related kinase B (TrkB in addition to serotonin (5-HT, neurotensin (NT, substance P (SP, calcitonin gene related peptide (CGRP, nitric oxide synthase (NOS, and parvalbumin (PV but not tyrosine decarboxylase (TH. It is speculated that BDNF released from projection neurons in the vlPAG might participate in the descending pain modulation through enhancing the presynaptic release of other neuroactive substances (NSs in the RVM.

  20. Alteration of GABAergic and glycinergic mechanisms by lidocaine injection in the rostral ventromedial medulla of neuropathic rats.

    Science.gov (United States)

    Saadé, Nayef E; Al Amin, Hassen; Tchachaghian, Sima; Jabbur, Suhayl J; Atweh, Samir F

    2010-04-01

    Attenuation of neuropathic manifestations in experimental animals, by lidocaine injection in the rostral ventro-medial medulla (RVM), has been traditionally attributed to selective block of a descending pain facilitatory system. However, the presence of descending fibers carrying this effect and the selective action of lidocaine on the facilitatory neurons, have not been supported by convincing experimental evidence. The present study aimed to investigate the mechanisms underlying the hypoalgesic action of lidocaine injection in the brainstem. Several groups of rats were subjected to mononeuropathy on their left hind paws, according to the model of spared nerve injury, and were subsequently implanted with guide cannulae in the RVM. After recovery, rats received injections of lidocaine, GABA and glycine agonists or antagonists and their effects were assessed on behavioral tests of allodynia and hyperalgesia. Injections of lidocaine at doses ranging between 0.05% and 2% produced attenuation at high doses and no effects or increasing hyperalgesia at low doses. GABA and glycine agonists increased neuropathic manifestations while their antagonists elicited the opposite effects. A combined injection of GABA agonist or glycine with lidocaine (0.5%) prevented the inhibitory effects of lidocaine injection alone. Our results are in line with the abundant documentation on the alteration of the function of inhibitory neurons by lidocaine and reveal a possible action of the injected high doses on the GABAergic and glycinergic neurons in the RVM. The resulting block of the inhibitory tone exerted by these neurons can lead to a release of the descending pain inhibitory systems.

  1. Neurotoxic lesion of the rostral perirhinal cortex blocks stress-induced exploratory behavioral changes in male rats.

    Science.gov (United States)

    Schulz-Klaus, Brigitte

    2009-03-01

    Exposure to stress leads to adaptive responses including both behavioral and physiological changes. This process is induced by the activation of multiple brain regions. The present study examined the role of the rostral perirhinal cortex (rPRh) in behavioral changes following electrical foot shock-induced stress. The rPRh of rats was lesioned bilaterally by local microinjections of 10 microg N-methyl-D-aspartic acid (NMDA) before foot shocks (0.7 mA, 1 s). The effects of these lesions on foot shock-induced changes in exploratory behaviors were tested in the open field (4 h, 48 h, 72 h, and 14 days after foot shocks) and the light-dark box (7 days after foot shocks). Foot-shocked and sham-lesioned rats showed several well known behavioral changes in the open field (e.g., immobility, reduction of exploratory activity) most marked at 48 h after foot shocks, and the light-dark box (e.g., reduction of time spent and activity in the lit compartment). All these stress-induced behavioral changes were blocked by neurotoxic lesions of the rPRh. Furthermore, rPRh lesions did not affect behavior in the open field and the light-dark box in unstressed rats. Taken together, these data indicate that the rPRh is involved in neurophysiological mechanisms that mediate changes induced by foot-shock stress in exploratory behaviors which indicate unconditioned fear or anxiety.

  2. Nocifensive behavior-related laser heat-evoked component in the rostral agranular insular cortex revealed using morphine analgesia.

    Science.gov (United States)

    Wu, Wen-Yi; Liu, Chan-Ying; Tsai, Meng-Li; Yen, Chen-Tung

    2016-02-01

    The rostral agranular insular cortex (RAIC), an opioid-responsive site, is essential for modulating nociception in rats. Our previous studies have shown that morphine suppressed long latency laser heat-evoked nociceptive responses in the primary somatosensory cortex (SmI). By contrast, morphine significantly attenuated both short and long latency responses in the anterior cingulate cortex (ACC). The present study assessed the effect of morphine on laser heat-evoked responses in the RAIC. Laser heat irradiation applied to the rat forepaws at graded levels was used as a specific noxious stimulus. In the RAIC, the first part of the long latency component (140-250ms) of the laser heat-evoked response was enhanced by intraperitoneal morphine (5mg/kg). When the laser heat-evoked cortical responses were examined for trials showing strong nocifensive movement (paw licking), moderate nocifensive movement (paw lifting), and no nocifensive movement, a 140-250ms period enhancement was observed in the RAIC only for the paw lifting movement. This enhancement was absent in the SmI. Thus, our data suggest that the RAIC has a pain-related behavior-dependent neuronal component. Furthermore, the RAIC, ACC, and SmI are differentially modulated by morphine analgesia.

  3. Selective C1 Lesioning Slightly Decreases Angiotensin II type I Receptor Expression in the Rat Rostral Ventrolateral Medulla (RVLM)

    Science.gov (United States)

    Bourassa, Erick A.; Stedenfeld, Kristen A.; Sved, Alan F.; Speth, Robert C.

    2015-01-01

    Cardiovascular homeostasis is regulated in large part by the rostral ventrolateral medulla (RVLM) in mammals. Projections from the RVLM to the intermediolateral column of the thoracolumbar spinal cord innervate preganglionic neurons of the sympathetic nervous system causing elevation of blood pressure and heart rate. A large proportion, but not all, of the neurons in the RVLM contain the enzymes necessary for the production of epinephrine and are identified as the C1 cell group. Angiotensin II (Ang II) activates the RVLM acting upon AT1 receptors. To assess the proportion of AT1 receptors that are located on C1 neurons in the rat RVLM this study employed an antibody to dopamine-beta-hydroxylase conjugated to saporin, to selectively destroy C1 neurons in the RVLM. Expression of tyrosine hydroxylase immunoreactive neurons in the RVLM was reduced by 57 % in the toxin injected RVLM compared to the contralateral RVLM. In contrast, densitometric analysis of autoradiographic images of 125I-sarcosine1, isoleucine8 Ang II binding to AT1 receptors of the injected side RVLM revealed a small (10%) reduction in AT1 receptor expression compared to the contralateral RVLM. These results suggest that the majority of AT1 receptors in the rat RVLM are located on non-C1 neurons or glia. PMID:26138553

  4. Identification and characterization of neuroblasts in the subventricular zone and rostral migratory stream of the adult human brain

    Institute of Scientific and Technical Information of China (English)

    Congmin Wang; Qiangqiang Zhang; Yue Zhang; Rui Chen; Hongjun Song; Zhengang Yang; Fang Liu; Ying-Ying Liu; Cai-Hong Zhao; Yan You; Lei Wang; Jingxiao Zhang; Bin Wei; Tong Ma

    2011-01-01

    It is of great interest to identify new neurons in the adult human brain,but the persistence of neurogenesis in the subventricular zone (SVZ) and the existence of the rostral migratory stream (RMS)-like pathway in the adult human forebrain remain highly controversial.In the present study,we have described the general configuration of the RMS in adult monkey,fetal human and adult human brains.We provide evidence that neuroblasts exist continuously in the anterior ventral SVZ and RMS of the adult human brain.The neuroblasts appear singly or in pairs without forming chains; they exhibit migratory morphologies and co-express the immature neuronal markers doublecortin,polysialylated neural cell adhesion molecule and βI-tubulin.Few of these neuroblasts appear to be actively proliferating in the anterior ventral SVZ but none in the RMS,indicating that neuroblasts distributed along the RMS are most likely derived from the ventral SVZ.Interestingly,no neuroblasts are found in the adult human olfactory bulb.Taken together,our data suggest that the SVZ maintains the ability to produce neuroblasts in the adult human brain.

  5. Holmes’ Tremor with Shoulder Pain Treated by Deep Brain Stimulation of Unilateral Ventral Intermediate Thalamic Nucleus and Globus Pallidus Internus

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    Sabri Aydın

    2017-05-01

    Full Text Available A 21-year-old male was admitted with severe right arm and hand tremors after a thalamic hemorrhage caused by a traffic accident. He was also suffering from agonizing pain in his right shoulder that manifested after the tremor. Neurologic examination revealed a disabling, severe, and irregular kinetic and postural tremor in the right arm during target-directed movements. There was also an irregular ipsilateral rest tremor and dystonic movements in the distal part of the right arm. The amplitude was moderate at rest and extremely high during kinetic and intentional movements. The patient underwent left globus pallidum internus and ventral intermediate thalamic nucleus deep brain stimulation. The patient improved by more than 80% as rated by the Fahn-Tolosa-Marin Tremor Rating Scale and Visual Analog Scale six months after surgery.

  6. Amnesia syndrome following left anterior thalamic infarction; with intrahemispheric and crossed cerebro-cerebellar diaschisis on brain SPECT.

    Science.gov (United States)

    Kim, M. H.; Hong, S. B.; Roh, J. K.

    1994-01-01

    We report a 61-year-old right-handed man developing disturbance of memory after a discrete thalamic infarction. Neuropsychological assessment revealed deficits in memory with retrograde and anterograde components, especially for verbal material. Brain MRI showed a left anterior thalamic infarction with normal angiographic findings. Despite the small lesion in the thalamus, he showed prolonged memory disturbance and a Brain SPECT image revealed decreased uptake in the ipsilateral fronto-temporo-parietal cortex and contralateral cerebellum. This diaschisis, a phenomenon caused by disconnection of the neural pathway helped us to evaluate the functional state of the patient and this imaging technique was valuable for obtaining to get more information for the evaluation of the neurological state and neuronal connections. In conclusion our findings correspond well with the understanding of amnesia as a disconnection syndrome because of the evidence of diaschisis on the Brain SPECT image. PMID:7702792

  7. 丘脑性失语症的临床研究%Clinical research on thalamic aphasia

    Institute of Scientific and Technical Information of China (English)

    麦卫华; 寇丽; 刘汉伟; 韩蓉蓉

    2011-01-01

    目的 探讨丘脑血管病所致的丘脑性失语症的言语特点、解剖机制及预后.方法 选择2002年6月至2008年7月我科收治的13例丘脑性失语症患者,采用汉语失语症检查法进行失语检查,同时行神经系统检查、常规实验室检查,及头颅CT、MRI检查.所有患者按原发病治疗.结果 13例患者均有自发言语减少,音量减少;3例伴命名障碍;10例伴错语;11例伴理解障碍.3例头颅CT示优势半球侧丘脑出血;头颅CT正常的10例中,9例头部MRI示优势半球丘脑腹外侧核中上部处腔隙性梗死灶、1例示优势半球丘脑背内侧核腔隙性梗死灶.所有患者于5~12天丘脑性失语的临床表现肖失.结论 丘脑性失语症有其独特的言语特点,优势半球侧丘脑腹外侧核和丘脑背内侧核可能为责任病灶区.头颅MRI对丘脑出血及梗死均敏感,能明确丘脑性失语症的病灶.经积极治疗原发病,丘脑性失语症预后较好.%Objective To study the language characteristics, anatomical mechanism and prognosis of thalamic aphasia caused by cerebrovascular diseases of thalamus. Methods Thirteen patients with thalamic aphasia during June 2002 to July 2008 in our department were studied. Aphasia examination, physical examination of central nervous system, routine laboratory examinations, as well as CT and MRI scanning of brain were taken. All patients were treated according to thalamic infarction or hemorrhage. Results All patients presented as sparse verbal output and low tone, 3 cases accompanied with anomia, 10 cases with paraphasia, and 11 cases with disturbance of comprehension. Thalamic hemorrhage in dominant hemisphere was detected in three cases by CT scanning. Among the other ten patients with normal CT, lacunar infarction in ventrolateral nucleus of thalamas (VL) of dominant hemisphere was detected in nine cases, while lacunar infarction in dorsomedial nucleus of thalamas ( DM ) of dominant hemisphere was detected in one

  8. May functional imaging be helpful for behavioral assessment in children? Regions of motor and associative cortico-subcortical circuits can be differentiated by laterality and rostrality

    Directory of Open Access Journals (Sweden)

    Julia M. August

    2015-06-01

    Full Text Available Background: Cortico-subcortical circuits are organized into the sensorimotor, associative and limbic loop. These neuronal preconditions play an important role regarding the understanding and treatment of behavioral problems in children. Differencing evidence argues for a lateralized organization of the sensorimotor loop and a bilateral (i.e. non-lateralized organization of the associative loop. However, a firm behavioral-neurobiological distinction of these circuits has been difficult, specifically in children. Objectives: Thus, the aim was a comprehensive functional visualization and differentiation of the sensorimotor and the associative circuit during childhood. As a new approach, laterality and rostrality features were used to distinguish between the two circuits within one single motor task. Methods: 24 healthy boys performed self-paced index finger tapping with each hand separately during functional magnetic resonance imaging at 3 Tesla. Results: A contrast analysis for left against right hand movement revealed lateralized activation in typical sensorimotor regions such as primary sensorimotor cortex, caudal supplementary motor area (SMA, caudal putamen and thalamus. A conjunction analysis confirmed bilateral involvement of known associative regions including pre-SMA, rostral SMA and rostral putamen. Conclusion: A functional visualization of two distinct corticostriatal circuits is provided in childhood. Both, the sensorimotor and associative circuit may be discriminated by their laterality characteristics already in minors. Additionally, the results support the concept of a modified functional subdivision of the SMA in a rostral (associative and caudal (motor part. A further development of this approach might help to nurture behavioral assessment and neurofeedback training in child mental health.

  9. Vector-induced NT-3 expression in rats promotes collateral growth of injured corticospinal tract axons far rostral to a spinal cord injury.

    Science.gov (United States)

    Weishaupt, N; Mason, A L O; Hurd, C; May, Z; Zmyslowski, D C; Galleguillos, D; Sipione, S; Fouad, K

    2014-07-11

    Rewiring the injured corticospinal tract (CST) by promoting connections between CST axons and spared neurons is a strategy being explored experimentally to achieve improved recovery of motor function after spinal cord injury (SCI). Reliable interventions to promote and direct growth of collaterals from injured CST axons are in high demand to promote functionally relevant detour pathways. A promising tool is neurotrophin-3 (NT-3), which has shown growth-stimulating and chemo-attractive effects for spared CST axons caudal to a CST lesion. Yet, efforts to promote growth of injured CST axons rostral to a SCI with NT-3 have been less successful to date. Evidence indicates that immune activation in the local growth environment, either intrinsic or induced by the endotoxin lipopolysaccharide (LPS), can play a decisive role in the CST's responsiveness to NT-3. Here, we test the potential of NT-3 as a tool to enhance and direct collateral growth from the injured CST rostral to a SCI (1) using long-term expression of NT-3 by adeno-associated viral vectors, (2) with and without stimulating the immune system with LPS. Our results indicate that inducing a growth response from injured CST axons into a region of vector-mediated NT-3 expression is possible in the environment of the spinal cord rostral to a SCI, but seems dependent on the distance between the responding axon and the source of NT-3. Our findings also suggest that injured CST axons do not increase their growth response to NT-3 after immune activation with LPS in this environment. In conclusion, this is to our knowledge the first demonstration that NT-3 can be effective at promoting growth of injured CST collaterals far rostral to a SCI. Making NT-3 available in close proximity to CST target axons may be the key to success when using NT-3 to rewire the injured CST in future investigations.

  10. Thalamic superoxide and peroxide handling capacity (SPHC): An experimental study with aluminum, ethanol and tocopherol in rats.

    Science.gov (United States)

    Nayak, Prasunpriya; Sharma, S B; Chowdary, N V S

    2015-09-01

    Superoxide and peroxide handling capacity (SPHC) is an important determinant of oxidative stress. Neurotoxic impacts of aluminum are associated with oxidant imbalance. Here, we studied the influence of aluminum on oxidative stress parameters, antioxidative enzymes and SPHC of thalamic area on pro-oxidant (ethanol) and antioxidant (α-tocopherol) exposure. Two sets of male Wistar rats were divided into 8 groups (6 each) and exposed to aluminum (10 mg/Kg body wt.), ethanol (0.6 g/Kg body wt.) and α-tocopherol (5 IU/day) for 4 wk, each having respective control group. Levels of reduced glutathione (GSH), lipid peroxidation (TBARS) along with activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) of thalamic area were estimated for each group. Glutathione-independent superoxide peroxide handling capacity (GI-SPHC) and glutathione-dependent superoxide peroxide handling capacity (GD-SPHC) were calculated from the GPx, CAT and SOD values. Concomitant exposure to aluminum and ethanol demonstrated significant increase in SOD activity and significant decrease in GPx activity compared to the control group, while lone aluminum-exposed rats showed raised GR activity, without alterations in GPx and SOD activities. However, significant reduction of both GI- and GD- SPHC were found in ethanol-exposed groups. α-Tocopherol supplementation could resist most of the alterations. In addition, current antioxidant exposure reduced the inherent GD-SPHC, and thus, made thalamic area more vulnerable to oxidant threat. The present study corroborates the thalamic susceptibility to aluminum-augmented oxidant imbalance and suggests cautious use of antioxidant supplementation against neurodegenerative disorders.

  11. Striatal and thalamic GABA level concentrations play differential roles for the modulation of response selection processes by proprioceptive information.

    Science.gov (United States)

    Dharmadhikari, Shalmali; Ma, Ruoyun; Yeh, Chien-Lin; Stock, Ann-Kathrin; Snyder, Sandy; Zauber, S Elizabeth; Dydak, Ulrike; Beste, Christian

    2015-10-15

    The selection of appropriate responses is a complex endeavor requiring the integration of many different sources of information in fronto-striatal-thalamic circuits. An often neglected but relevant piece of information is provided by proprioceptive inputs about the current position of our limbs. This study examines the importance of striatal and thalamic GABA levels in these processes using GABA-edited magnetic resonance spectroscopy (GABA-MRS) and a Simon task featuring proprioception-induced interference in healthy subjects. As a possible model of deficits in the processing of proprioceptive information, we also included Parkinson's disease (PD) patients in this study. The results show that proprioceptive information about unusual postures complicates response selection processes in controls, but not in PD patients. The well-known deficits of PD patients in processing proprioceptive information can turn into a benefit when altered proprioceptive information would normally complicate response selection processes. Striatal and thalamic GABA levels play dissociable roles in the modulation of response selection processes by proprioceptive information: Striatal GABA levels seem to be important for the general speed of responding, most likely because striatal GABA promotes response selection. In contrast, the modulation of response conflict by proprioceptive information is closely related to thalamic GABA concentrations with higher concentration being related to a smaller response conflict effect. The most likely explanation for this finding is that the thalamus is involved in the integration of sensorimotor, attentional, and cognitive information for the purpose of response formation. Yet, this effect in the thalamus vanishes when controls and PD patients were analyzed separately.

  12. Thalamic nuclei segmentation in clinical 3T T1-weighted Images using high-resolution 7T shape models

    Science.gov (United States)

    Liu, Yuan; D'Haese, Pierre-François; Newton, Allen T.; Dawant, Benoit M.

    2015-03-01

    Accurate and reliable identification of thalamic nuclei is important for surgical interventions and neuroanatomical studies. This is a challenging task due to their small sizes and low intra-thalamic contrast in standard T1-weighted or T2- weighted images. Previously proposed techniques rely on diffusion imaging or functional imaging. These require additional scanning and suffer from the low resolution and signal-to-noise ratio in these images. In this paper, we aim to directly segment the thalamic nuclei in standard 3T T1-weighted images using shape models. We manually delineate the structures in high-field MR images and build high resolution shape models from a group of subjects. We then investigate if the nuclei locations can be inferred from the whole thalamus. To do this, we hierarchically fit joint models. We start from the entire thalamus and fit a model that captures the relation between the thalamus and large nuclei groups. This allows us to infer the boundaries of these nuclei groups and we repeat the process until all nuclei are segmented. We validate our method in a leave-one-out fashion with seven subjects by comparing the shape-based segmentations on 3T images to the manual contours. Results we have obtained for major nuclei (dice coefficients ranging from 0.57 to 0.88 and mean surface errors from 0.29mm to 0.72mm) suggest the feasibility of using such joint shape models for localization. This may have a direct impact on surgeries such as Deep Brain Stimulation procedures that require the implantation of stimulating electrodes in specific thalamic nuclei.

  13. Thalamic pathology and memory loss in early Alzheimer's disease: moving the focus from the medial temporal lobe to Papez circuit.

    Science.gov (United States)

    Aggleton, John P; Pralus, Agathe; Nelson, Andrew J D; Hornberger, Michael

    2016-07-01

    It is widely assumed that incipient protein pathology in the medial temporal lobe instigates the loss of episodic memory in Alzheimer's disease, one of the earliest cognitive deficits in this type of dementia. Within this region, the hippocampus is seen as the most vital for episodic memory. Consequently, research into the causes of memory loss in Alzheimer's disease continues to centre on hippocampal dysfunction and how disease-modifying therapies in this region can potentially alleviate memory symptomology. The present review questions this entrenched notion by bringing together findings from post-mortem studies, non-invasive imaging (including studies of presymptomatic, at-risk cases) and genetically modified animal models. The combined evidence indicates that the loss of episodic memory in early Alzheimer's disease reflects much wider neurodegeneration in an extended mnemonic system (Papez circuit), which critically involves the limbic thalamus. Within this system, the anterior thalamic nuclei are prominent, both for their vital contributions to episodic memory and for how these same nuclei appear vulnerable in prodromal Alzheimer's disease. As thalamic abnormalities occur in some of the earliest stages of the disease, the idea that such changes are merely secondary to medial temporal lobe dysfunctions is challenged. This alternate view is further strengthened by the interdependent relationship between the anterior thalamic nuclei and retrosplenial cortex, given how dysfunctions in the latter cortical area provide some of the earliest in vivo imaging evidence of prodromal Alzheimer's disease. Appreciating the importance of the anterior thalamic nuclei for memory and attention provides a more balanced understanding of Alzheimer's disease. Furthermore, this refocus on the limbic thalamus, as well as the rest of Papez circuit, would have significant implications for the diagnostics, modelling, and experimental treatment of cognitive symptoms in Alzheimer's disease.

  14. Newly observed thalamic involvement and mutations of the HEXA gene in a Korean patient with juvenile GM2 gangliosidosis.

    Science.gov (United States)

    Lee, Soon Min; Lee, Min Jung; Lee, Joon Soo; Kim, Heung Dong; Lee, Jin Sung; Kim, Jinna; Lee, Seung Koo; Lee, Young Mock

    2008-09-01

    Neuroimaging studies of patients with GM2 gangliosidosis are rare. The thalamus and basal ganglia are principally involved in patients affected by the infantile form of GM2 gangliosidosis. Unlike in the infantile form, in juvenile or adult type GM2 gangliosidosis, progressive cortical and cerebellar atrophy is the main abnormality seen on conventional magnetic resonance imaging (MRI); no basal ganglial or thalamic impairment were observed. This report is of a Korean girl with subacute onset, severe deficiency of hexosaminidase A activity and mutations (Arg137Term, Ala246Thr) of the HEXA gene. A 3.5-year-old girl who was previously in good health was evaluated for hypotonia and ataxia 3 months ago and showed progressive developmental deterioration, including cognitive decline. Serial brain MRI showed progressive overall volume decrease of the entire brain and thalamic atrophy. Fluorine-18 FDG PET scan showed severe decreased uptake in bilateral thalamus and diffuse cerebral cortex. We suggest, through our experience, that the thalamic involvement in MR imaging and FDG-PET can be observed in the juvenile form of GM2 gangliosidosis, and we suspect the association of mutations in the HEXA gene.

  15. Spikes and bursts in two types of thalamic projection neurons differentially shape sleep patterns and auditory responses in a songbird.

    Science.gov (United States)

    Hahnloser, Richard H R; Wang, Claude Z-H; Nager, Aymeric; Naie, Katja

    2008-05-07

    In mammals, the thalamus plays important roles for cortical processing, such as relay of sensory information and induction of rhythmical firing during sleep. In neurons of the avian cerebrum, in analogy with cortical up and down states, complex patterns of regular-spiking and dense-bursting modes are frequently observed during sleep. However, the roles of thalamic inputs for shaping these firing modes are largely unknown. A suspected key player is the avian thalamic nucleus uvaeformis (Uva). Uva is innervated by polysensory input, receives indirect cerebral feedback via the midbrain, and projects to the cerebrum via two distinct pathways. Using pharmacological manipulation, electrical stimulation, and extracellular recordings of Uva projection neurons, we study the involvement of Uva in zebra finches for the generation of spontaneous activity and auditory responses in premotor area HVC (used as a proper name) and the downstream robust nucleus of the arcopallium (RA). In awake and sleeping birds, we find that single Uva spikes suppress and spike bursts enhance spontaneous and auditory-evoked bursts in HVC and RA neurons. Strong burst suppression is mediated mainly via tonically firing HVC-projecting Uva neurons, whereas a fast burst drive is mediated indirectly via Uva neurons projecting to the nucleus interface of the nidopallium. Our results reveal that cerebral sleep-burst epochs and arousal-related burst suppression are both shaped by sophisticated polysynaptic thalamic mechanisms.

  16. Decreased spontaneous activity and altered evoked nociceptive response of rat thalamic submedius neurons to lumbar vertebra thrust.

    Science.gov (United States)

    Reed, William R; Cranston, Jamie T; Onifer, Stephen M; Little, Joshua W; Sozio, Randall S

    2017-07-07

    The thalamus is a central structure important to modulating and processing all mechanoreceptor input destined for the cortex. A large number of diverse mechanoreceptor endings are stimulated when a high velocity low amplitude thrust is delivered to the lumbar spine during spinal manipulation. The objective of this study was to determine if a lumbar thrust alters spontaneous and/or evoked nociceptive activity in medial thalamic submedius (Sm) neurons. Extracellular recordings were obtained from 94 thalamic Sm neurons in 54 urethane-anesthetized adult Wistar rats. Spontaneous activity was recorded 5 min before and after an L5 control (no thrust) and thrust (85% rat body weight; 100 ms) procedure. In a subset of responsive nociceptive-specific neurons, mean changes in noxious-evoked response (10-s pinch with clip; 795 g) at three sites (tail, contra- and ipsilateral hindpaw) were determined following an L5 thrust. Mean changes in Sm spontaneous activity (60 s bins) and evoked noxious response were compared using a mixed model repeated measures ANOVA with Bonferroni post hoc t tests and paired t tests, respectively. Compared to control, spontaneous Sm activity decreased 180-240 s following the lumbar thrust (p thrust compared to control (p thrust suggest that thalamic submedius neurons may play a role in central pain modulation related to manual therapy intervention.

  17. Childhood maltreatment is associated with larger left thalamic gray matter volume in adolescents with generalized anxiety disorder.

    Science.gov (United States)

    Liao, Mei; Yang, Fan; Zhang, Yan; He, Zhong; Song, Ming; Jiang, Tianzi; Li, Zexuan; Lu, Shaojia; Wu, Weiwei; Su, Linyan; Li, Lingjiang

    2013-01-01

    Generalized anxiety disorder (GAD) is a common anxiety disorder that usually begins in adolescence. Childhood maltreatment is highly prevalent and increases the possibility for developing a variety of mental disorders including anxiety disorders. An earlier age at onset of GAD is significantly related to maltreatment in childhood. Exploring the underpinnings of the relationship between childhood maltreatment and adolescent onset GAD would be helpful in identifying the potential risk markers of this condition. Twenty-six adolescents with GAD and 25 healthy controls participated in this study. A childhood trauma questionnaire (CTQ) was introduced to assess childhood maltreatment. All subjects underwent high-resolution structural magnetic resonance scans. Voxel-based morphometry (VBM) was used to investigate gray matter alterations. Significantly larger gray matter volumes of the right putamen were observed in GAD patients compared to healthy controls. In addition, a significant diagnosis-by-maltreatment interaction effect for the left thalamic gray matter volume was revealed, as shown by larger volumes of the left thalamic gray matter in GAD patients with childhood maltreatment compared with GAD patients without childhood maltreatment as well as with healthy controls with/without childhood maltreatment. A significant positive association between childhood maltreatment and left thalamic gray matter volume was only seen in GAD patients. These findings revealed an increased volume in the subcortical regions in adolescent GAD, and the alterations in the left thalamus might be involved in the association between childhood maltreatment and the occurrence of GAD.

  18. Thalamic shape and connectivity abnormalities in children with attention-deficit/hyperactivity disorder.

    Science.gov (United States)

    Xia, Shugao; Li, Xiaobo; Kimball, Ariane E; Kelly, Mary S; Lesser, Iris; Branch, Craig

    2012-11-30

    Attention-deficit/hyperactivity disorder (ADHD) is characterized by widespread structural and functional abnormalities in the cortico-striato-thalmo-cortical (CSTC) loops that subserve attention and executive functions. In this study, we analyzed thalamic shape and its white matter connections using structural magnetic resonance imaging and diffusion (DTI) data acquired from children with ADHD (n=19) and controls (n=19). Shape morphology of the thalamus was assessed using shape-based analysis, while connectivity between the thalamus and other brain regions was determined using probabilistic diffusion tractography. Shape-based analysis indicated significant regional atrophy in the left thalamus in children with ADHD compared to controls. Group analyses of white matter connectivity measures showed significantly decreased mean fractional anisotropy (FA) and volume of the tracts between thalamus and striatum, hippocampus, and prefrontal lobe in children with ADHD compared to controls. The structural abnormalities within the thalamus and the reduced integrity of the white matter tracks between the thalamus and other brain regions, as shown from the results of this study, may be the anatomical bases of the impaired cognitive performances in the attention and executive function domains in ADHD.

  19. Thalamic reticular impairment underlies attention deficit in Ptchd1(Y/-) mice.

    Science.gov (United States)

    Wells, Michael F; Wimmer, Ralf D; Schmitt, L Ian; Feng, Guoping; Halassa, Michael M

    2016-04-07

    Developmental disabilities, including attention-deficit hyperactivity disorder (ADHD), intellectual disability (ID), and autism spectrum disorders (ASD), affect one in six children in the USA. Recently, gene mutations in patched domain containing 1 (PTCHD1) have been found in ~1% of patients with ID and ASD. Individuals with PTCHD1 deletion show symptoms of ADHD, sleep disruption, hypotonia, aggression, ASD, and ID. Although PTCHD1 is probably critical for normal development, the connection between its deletion and the ensuing behavioural defects is poorly understood. Here we report that during early post-natal development, mouse Ptchd1 is selectively expressed in the thalamic reticular nucleus (TRN), a group of GABAergic neurons that regulate thalamocortical transmission, sleep rhythms, and attention. Ptchd1 deletion attenuates TRN activity through mechanisms involving small conductance calcium-dependent potassium currents (SK). TRN-restricted deletion of Ptchd1 leads to attention deficits and hyperactivity, both of which are rescued by pharmacological augmentation of SK channel activity. Global Ptchd1 deletion recapitulates learning impairment, hyper-aggression, and motor defects, all of which are insensitive to SK pharmacological targeting and not found in the TRN-restricted deletion mouse. This study maps clinically relevant behavioural phenotypes onto TRN dysfunction in a human disease model, while also identifying molecular and circuit targets for intervention.

  20. Comorbid Asperger and Tourette syndromes with localized mesencephalic, infrathalamic, thalamic, and striatal damage.

    Science.gov (United States)

    Berthier, Marcelo L; Kulisevsky, Jaime; Asenjo, Beatriz; Aparicio, Jesús; Lara, Diego

    2003-03-01

    We describe the coexistence of Asperger and Tourette syndromes (AS and TS) caused by discrete hypoxic-ischaemic necrosis of the midbrain, infrathalamic and thalamic nuclei, and striatum in an adolescent male with positive family history for tics and obsessive-compulsive disorder. Behavioural ratings, cognitive tests, and volumetric measurements of the basal ganglia were performed in the patient and five other individuals with AS-TS unassociated with MRI lesions. Cognitive deficits in attentional, executive, and visual-spatial domains were found both in the patient and control AS-TS group, though deficits were more severe in the former. MRI showed reduction of the left basal ganglia volume compared with the right in the patient, whereas the control group showed reduction of right basal ganglia volume compared with the left. It is suggested that individuals with a genetic predisposition to TS may develop AS and TS after involvement of midbrain and related components of basal ganglia-thalamocortical circuits normally implicated in the integration of emotional, cognitive, and motor functions.

  1. Impaired spatial working memory after anterior thalamic lesions: recovery with cerebrolysin and enrichment.

    Science.gov (United States)

    Loukavenko, Elena A; Wolff, Mathieu; Poirier, Guillaume L; Dalrymple-Alford, John C

    2016-05-01

    Lesions to the anterior thalamic nuclei (ATN) in rats produce robust spatial memory deficits that reflect their influence as part of an extended hippocampal system. Recovery of spatial working memory after ATN lesions was examined using a 30-day administration of the neurotrophin cerebrolysin and/or an enriched housing environment. As expected, ATN lesions in standard-housed rats given saline produced severely impaired reinforced spatial alternation when compared to standard-housed rats with sham lesions. Both cerebrolysin and enrichment substantially improved this working memory deficit, including accuracy on trials that required attention to distal cues for successful performance. The combination of cerebrolysin and enrichment was more effective than either treatment alone when the delay between successive runs in a trial was increased to 40 s. Compared to the intact rats, ATN lesions in standard-housed groups produced substantial reduction in c-Fos expression in the retrosplenial cortex, which remained low after cerebrolysin and enrichment treatments. Evidence that multiple treatment strategies restore some memory functions in the current lesion model reinforces the prospect for treatments in human diencephalic amnesia.

  2. Corticothalamic Synaptic Noise as a Mechanism for Selective Attention in Thalamic Neurons

    Directory of Open Access Journals (Sweden)

    Sébastien eBéhuret

    2015-12-01

    Full Text Available A reason why the thalamus is more than a passive gateway for sensory signals is that two-third of the synapses of thalamocortical neurons are directly or indirectly related to the activity of corticothalamic axons. While the responses of thalamocortical neurons evoked by sensory stimuli are well characterized, with ON- and OFF-center receptive field structures, the prevalence of synaptic noise resulting from neocortical feedback in intracellularly recorded thalamocortical neurons in vivo has attracted little attention. However, in vitro and modeling experiments point to its critical role for the integration of sensory signals. Here we combine our recent findings in a unified framework suggesting the hypothesis that corticothalamic synaptic activity is adapted to modulate the transfer efficiency of thalamocortical neurons during selective attention at three different levels: First, on ionic channels by interacting with intrinsic membrane properties, second at the neuron level by impacting on the input-output gain, and third even more effectively at the cell assembly level by boosting the information transfer of sensory features encoded in thalamic subnetworks. This top-down population control is achieved by tuning the correlations in subthreshold membrane potential fluctuations and is adapted to modulate the transfer of sensory features encoded by assemblies of thalamocortical relay neurons. We thus propose that cortically-controlled (de-correlation of subthreshold noise is an efficient and swift dynamic mechanism for selective attention in the thalamus.

  3. Corticothalamic Synaptic Noise as a Mechanism for Selective Attention in Thalamic Neurons.

    Science.gov (United States)

    Béhuret, Sébastien; Deleuze, Charlotte; Bal, Thierry

    2015-01-01

    A reason why the thalamus is more than a passive gateway for sensory signals is that two-third of the synapses of thalamocortical neurons are directly or indirectly related to the activity of corticothalamic axons. While the responses of thalamocortical neurons evoked by sensory stimuli are well characterized, with ON- and OFF-center receptive field structures, the prevalence of synaptic noise resulting from neocortical feedback in intracellularly recorded thalamocortical neurons in vivo has attracted little attention. However, in vitro and modeling experiments point to its critical role for the integration of sensory signals. Here we combine our recent findings in a unified framework suggesting the hypothesis that corticothalamic synaptic activity is adapted to modulate the transfer efficiency of thalamocortical neurons during selective attention at three different levels: First, on ionic channels by interacting with intrinsic membrane properties, second at the neuron level by impacting on the input-output gain, and third even more effectively at the cell assembly level by boosting the information transfer of sensory features encoded in thalamic subnetworks. This top-down population control is achieved by tuning the correlations in subthreshold membrane potential fluctuations and is adapted to modulate the transfer of sensory features encoded by assemblies of thalamocortical relay neurons. We thus propose that cortically-controlled (de-)correlation of subthreshold noise is an efficient and swift dynamic mechanism for selective attention in the thalamus.

  4. The slow oscillation in cortical and thalamic networks: mechanisms and functions

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    Garrett T. Neske

    2016-01-01

    Full Text Available During even the most quiescent behavioral periods, the cortex and thalamus express rich spontaneous activity in the form of slow (<1 Hz, synchronous network state transitions. Throughout this so-called slow oscillation, cortical and thalamic neurons fluctuate between periods of intense synaptic activity (Up states and almost complete silence (Down states. The two decades since the original characterization of the slow oscillation in the cortex and thalamus have seen considerable advances in deciphering the cellular and network mechanisms associated with this pervasive phenomenon. There are, nevertheless, many questions regarding the slow oscillation that await more thorough illumination, particularly the mechanisms by which Up states initiate and terminate, the functional role of the rhythmic activity cycles in unconscious or minimally conscious states, and the precise relation between Up states and the activated states associated with waking behavior. Given the substantial advances in multineuronal recording and imaging methods in both in vivo and in vitro preparations, the time is ripe to take stock of our current understanding of the slow oscillation and pave the way for future investigations of its mechanisms and functions. My aim in this Review is to provide a comprehensive account of the mechanisms and functions of the slow oscillation, and to suggest avenues for further exploration.

  5. Abnormal EEG Complexity and Functional Connectivity of Brain in Patients with Acute Thalamic Ischemic Stroke

    Science.gov (United States)

    Liu, Shuang; Guo, Jie; Meng, Jiayuan; Wang, Zhijun; Yao, Yang; Yang, Jiajia; Qi, Hongzhi; Ming, Dong

    2016-01-01

    Ischemic thalamus stroke has become a serious cardiovascular and cerebral disease in recent years. To date the existing researches mostly concentrated on the power spectral density (PSD) in several frequency bands. In this paper, we investigated the nonlinear features of EEG and brain functional connectivity in patients with acute thalamic ischemic stroke and healthy subjects. Electroencephalography (EEG) in resting condition with eyes closed was recorded for 12 stroke patients and 11 healthy subjects as control group. Lempel-Ziv complexity (LZC), Sample Entropy (SampEn), and brain network using partial directed coherence (PDC) were calculated for feature extraction. Results showed that patients had increased mean LZC and SampEn than the controls, which implied the stroke group has higher EEG complexity. For the brain network, the stroke group displayed a trend of weaker cortical connectivity, which suggests a functional impairment of information transmission in cortical connections in stroke patients. These findings suggest that nonlinear analysis and brain network could provide essential information for better understanding the brain dysfunction in the stroke and assisting monitoring or prognostication of stroke evolution. PMID:27403202

  6. Simple cortical and thalamic neuron models for digital arithmetic circuit implementation

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    Takuya eNanami

    2016-05-01

    Full Text Available Trade-off between reproducibility of neuronal activities and computational efficiency is one ofcrucial subjects in computational neuroscience and neuromorphic engineering. A wide variety ofneuronal models have been studied from different viewpoints. The digital spiking silicon neuron(DSSN model is a qualitative model that focuses on efficient implementation by digital arithmeticcircuits. We expanded the DSSN model and found appropriate parameter sets with which itreproduces the dynamical behaviors of the ionic-conductance models of four classes of corticaland thalamic neurons. We first developed a 4-variable model by reducing the number of variablesin the ionic-conductance models and elucidated its mathematical structures using bifurcationanalysis. Then, expanded DSSN models were constructed that reproduce these mathematicalstructures and capture the characteristic behavior of each neuron class. We confirmed thatstatistics of the neuronal spike sequences are similar in the DSSN and the ionic-conductancemodels. Computational cost of the DSSN model is larger than that of the recent sophisticatedIntegrate-and-Fire-based models, but smaller than the ionic-conductance models. This modelis intended to provide another meeting point for above trade-off that satisfies the demand forlarge-scale neuronal network simulation with closer-to-biology models.

  7. Modulation of temporal precision in thalamic population responses to natural visual stimuli

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    Gaelle eDesbordes

    2010-11-01

    Full Text Available Natural visual stimuli have highly structured spatial and temporal properties which influence the way visual information is encoded in the visual pathway. In response to natural scene stimuli, neurons in the lateral geniculate nucleus (LGN are temporally precise—on a time scale of 10-25 ms—both within single cells and across cells within a population. This time scale, established by non stimulus-driven elements of neuronal firing, is significantly shorter than that of natural scenes, yet is critical for the neural representation of the spatial and temporal structure of the scene. Here, a generalized linear model (GLM that combines stimulus-driven elements with spike-history dependence associated with intrinsic cellular dynamics is shown to predict the fine timing precision of LGN responses to natural scene stimuli, the corresponding correlation structure across nearby neurons in the population, and the continuous modulation of spike timing precision and latency across neurons. A single model captured the experimentally observed neural response, across different levels of contrasts and different classes of visual stimuli, through interactions between the stimulus correlation structure and the nonlinearity in spike generation and spike history dependence. Given the sensitivity of the thalamocortical synapse to closely timed spikes and the importance of fine timing precision for the faithful representation of natural scenes, the modulation of thalamic population timing over these time scales is likely important for cortical representations of the dynamic natural visual environment.

  8. Amygdalar, hippocampal, and thalamic volumes in youth at high risk for development of bipolar disorder

    Science.gov (United States)

    Karchemskiy, Asya; Garrett, Amy; Howe, Meghan; Adleman, Nancy; Simeonova, Diana I.; Alegria, Dylan; Reiss, Allan; Chang, Kiki

    2011-01-01

    Children of parents with bipolar disorder (BD), especially those with attention deficit hyperactivity disorder (ADHD) and symptoms of depression or mania, are significantly at high-risk for developing BD. As we have previously shown amygdalar reductions in pediatric BD, the current study examined amygdalar volumes in offspring of parents with (BD offspring) who have not yet developed a full manic episode. Youth participating in the study included 22 BD offspring and 22 healthy controls of comparable age, gender, handedness, and IQ. Subjects had no history of a manic episode, but met criteria for ADHD and moderate mood symptoms. MRI was performed on a 3T GE scanner, using a 3D volumetric spoiled gradient echo series. Amygdalae were manually traced using BrainImage Java software on positionally normalized brain stacks. Bipolar offspring had similar amygdalar volumes compared to the control group. Exploratory analyses yielded no differences in hippocampal or thalamic volumes. Bipolar offspring do not show decreased amygdala volume, possibly because these abnormalities occur after more prolonged illness rather than as a preexisting risk factor. Longitudinal studies are needed to determine whether amygdalar volumes change during and after the development of BD. PMID:22041532

  9. Characterization of Behaviour and Remote Degeneration Following Thalamic Stroke in the Rat

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    Nina Weishaupt

    2015-06-01

    Full Text Available Subcortical ischemic strokes are among the leading causes of cognitive impairment. Selective atrophy of remote brain regions connected to the infarct is thought to contribute to deterioration of cognitive functions. The mechanisms underlying this secondary degenerative process are incompletely understood, but are thought to include inflammation. We induce ischemia by unilateral injection of endothelin-I into the rat dorsomedial thalamic nucleus, which has defined reciprocal connections to the frontal cortex. We use a comprehensive test battery to probe for changes in behaviour, including executive functions. After a four-week recovery period, brain sections are stained with markers for degeneration, microglia, astrocytes and myelin. Degenerative processes are localized within the stroke core and along the full thalamocortical projection, which does not translate into measurable behavioural deficits. Significant microglia recruitment, astrogliosis or myelin loss along the axonal projection or within the frontal cortex cannot be detected. These findings indicate that critical effects of stroke-induced axonal degeneration may only be measurable beyond a threshold of stroke severity and/or follow a different time course. Further investigations are needed to clarify the impact of inflammation accompanying axonal degeneration on delayed remote atrophy after stroke.

  10. Successful Treatment of Refractory Status Epilepticus Using Anterior Thalamic Nuclei Deep Brain Stimulation.

    Science.gov (United States)

    Lee, Ching-Yi; Lim, Siew-Na; Wu, Tony; Lee, Shih-Tseng

    2017-03-01

    Refractory status epilepticus (RSE) is considered a medical emergency in neurology and is related to high mortality. We report a successfully treated case of RSE using deep brain stimulation (DBS) at the anterior thalamic nuclei (ATN) in a 17-year-old woman. This patient developed RSE as a result of progressive seizure activity. RSE with generalized tonic-clonic seizures was noted 2 weeks before admission. Video electroencephalography monitoring showed continuous 3-Hz generalized spike-and-wave complexes with higher amplitude over bilateral frontal. Four weeks after RSE onset, bilateral DBS of the ATN was started. This treatment was immediately followed by the disappearance of tonic-clonic seizures and spike-and-wave complexes, suggesting resolution of the RSE. Significant clinical improvement was noted 1 week after DBS implantation. DBS at the ATN significantly improved both the electroencephalography and clinical presentation in the patient with RSE. DBS at the ATN should be considered as a possible treatment choice once a patient develops RSE. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  11. [Neuronal mechanisms of motor signal transmission in thalamic Voi nucleus in spasmodic torticollis patients].

    Science.gov (United States)

    Sedov, A S; Raeva, S N; Pavlenko, V B

    2014-01-01

    Neural mechanisms of motor signal transmission in ventrooral (Voi) nucleus of motor thalamus during the realization-of voluntary and involuntary abnormal (dystonic) movements in patients with spasmodic torticollis were investigated by means of microelectrode technique. The high reactivity of the cellular Voi elements to various functional (mainly motor) tests was proved. Analysis of neuronal activity showed: (1) the difference of neural mechanisms of motor signal transmission in the realization of voluntary movement with and without the involvement of the pathological axial neck muscles, as well as passive and abnormal involuntary dystonic movements; (2) significance of sensory component in the mechanisms of sensorimotor interactions during realization of voluntary and involuntary dystonic head and neck movements, causing the activation of the axial neck muscles; (3) important role of the rhythmic and synchronized neuronal activity in motor signal transmission during the realization of active and passive movements. Participation of Voi nucleus in pathological mechanisms of spasmodic torticollis was shown. The data obtained can be used for identificatiori of Voi thalamic nucleus during stereotactic neurosurgical operations in patients with spasmodic torticollis for selection the optimum destruction (stimulation) target and reduction of postoperative effects.

  12. Ophthalmoplegic migraine with reversible thalamic ischemia by Tc-99m ethylcysteinate dimer brain SPECT

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    Kim, Jong Ho; Shin, Dong Jin; Kang, Sung Soo [Gachon Medical School, Gil Medical Center, Inchon (Korea, Republic of)

    1999-07-01

    Two patients presented with ophthalmoplegic migraine (OM) underwent EEG, Brain-MRI, cerebral angiography, and Tc-99m ECD SPECT during an attack. Follow-up SPECT was performed after neurologic symptoms resolved. In both cases, SPECT during an attack of ophthalmoplegia and headache demonstrated a significantly decreased regional cerebral blood flow in the thalamus to the side of ophthalmoplegia, which was normalized on the follow-up SPECT during a symptom free recovery phase (Lesion to Non-lesion thalamic ratio=1.19 to 0.96 and 1.16 to 0.98, respectively). The other roentgenographic and laboratory findings were normal. These findings are suggestive the ischemia in the perforators of PCA results in third nerve palsy because the portion of oculomotor nerve behind the cavernous sinus derives its blood supply from small perforating branches of the basilar and PCA. Matched ictal hypoperfusion of the thalamus to the site of ophthalmoplegic migraine is suggestive of the ischemic neuropathy as an etiology of OM.

  13. Distinct Thalamic Reticular Cell Types Differentially Modulate Normal and Pathological Cortical Rhythms

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    Alexandra Clemente-Perez

    2017-06-01

    Full Text Available Integrative brain functions depend on widely distributed, rhythmically coordinated computations. Through its long-ranging connections with cortex and most senses, the thalamus orchestrates the flow of cognitive and sensory information. Essential in this process, the nucleus reticularis thalami (nRT gates different information streams through its extensive inhibition onto other thalamic nuclei, however, we lack an understanding of how different inhibitory neuron subpopulations in nRT function as gatekeepers. We dissociated the connectivity, physiology, and circuit functions of neurons within rodent nRT, based on parvalbumin (PV and somatostatin (SOM expression, and validated the existence of such populations in human nRT. We found that PV, but not SOM, cells are rhythmogenic, and that PV and SOM neurons are connected to and modulate distinct thalamocortical circuits. Notably, PV, but not SOM, neurons modulate somatosensory behavior and disrupt seizures. These results provide a conceptual framework for how nRT may gate incoming information to modulate brain-wide rhythms.

  14. Neurons in the thalamic reticular nucleus are selective for diverse and complex visual features

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    Vishal eVaingankar

    2012-12-01

    Full Text Available All visual signals the cortex receives are influenced by the perigeniculate sector of the thalamic reticular nucleus, which receives input from relay cells in the lateral geniculate and provides feedback inhibition in return. Relay cells have been studied in quantitative depth; they behave in a roughly linear fashion and have receptive fields with a stereotyped centre-surround structure. We know far less about reticular neurons. Qualitative studies indicate they simply pool ascending input to generate nonselective gain control. Yet the perigeniculate is complicated; local cells are densely interconnected and fire lengthy bursts. Thus, we employed quantitative methods to explore the perigeniculate, using relay cells as controls. By adapting methods of spike-triggered averaging and covariance analysis for bursts, we identified both first and second order features that build reticular receptive fields. The shapes of these spatiotemporal subunits varied widely; no stereotyped pattern emerged. Companion experiments showed that the shape of the first but not second order features could be explained by the overlap of On and Off inputs to a given cell. Moreover, we assessed the predictive power of the receptive field and how much information each component subunit conveyed. Linear-nonlinear models including multiple subunits performed better than those made with just one; further each subunit encoded different visual information. Model performance for reticular cells was always lesser than for relay cells, however, indicating that reticular cells process inputs nonlinearly. All told, our results suggest that the perigeniculate encodes diverse visual features to selectively modulate activity transmitted downstream

  15. Entrainment of slow oscillations of auditory thalamic neurons by repetitive sound stimuli.

    Science.gov (United States)

    Gao, Lixia; Meng, Xiankai; Ye, Changquan; Zhang, Haitian; Liu, Chunhua; Dan, Yang; Poo, Mu-Ming; He, Jufang; Zhang, Xiaohui

    2009-05-06

    Slow oscillations at frequencies potential. Although up and down states are known to differentially affect sensory-evoked responses, whether and how they are modulated by sensory stimuli are not well understood. In the present study, intracellular recording in anesthetized guinea pigs showed that membrane potentials of nonlemniscal auditory thalamic neurons exhibited spontaneous up/down transitions at random intervals in the range of 2-30 s, which could be entrained to a regular interval by repetitive sound stimuli. After termination of the entraining stimulation (ES), regular up/down transitions persisted for several cycles at the ES interval. Furthermore, the efficacy of weak sound stimuli in triggering the up-to-down transition was potentiated specifically at the ES interval for at least 10 min. Extracellular recordings in the auditory thalamus of unanesthetized guinea pigs also showed entrainment of slow oscillations by rhythmic sound stimuli during slow wave sleep. These results demonstrate a novel form of network plasticity, which could help to retain the information of stimulus interval on the order of seconds.

  16. Gait balance disorder by thalamic infarction with the disorder of interstitial nucleus of cajal.

    Science.gov (United States)

    Kurosu, A; Hayashi, Y; Wada, K; Nagaoka, M

    2011-01-01

    The interstitial nucleus of Cajal (INC) is thought to play an important role in torsional/vertical eye position and head posture, and disorders of the INC induce abnormal ocular movements and head tilt. Our patients with ocular tilt reactions simultaneously also had disturbances in ambulatory balance, yet no reports address the loss of balance control induced by disorders of the INC. We examined the ambulatory disturbances induced by INC lesion. We experienced three patients with ocular movement disorders and abnormal head tilt due to thalamic infarction. We performed ophthalmic examinations on and checked the balance of them. With funduscopy, abnormal cycloduction was seen in the unaffected side and normal cycloduction was observed in the affected side. Nevertheless, Hess charts showed distortions in the visual image of both eyes. They all had disorders of balance control. We tried to treat them using the Bobath approach for improving their ambulatory balance. With subsequent improvements in balance control it was possible for them to take short walks, but it was difficult to make any improvements in their ocular movement. The INC is related to balance control of ambulation and disorders of the INC induce ambulatory disturbances. Cycloduction was only observed in the unaffected side, but Hess charts showed distortions of the visual image in both eyes. Ambulation was briefly improved, but diplopia persisted in these patients.

  17. Gait Balance Disorder by Thalamic Infarction with the Disorder of Interstitial Nucleus of Cajal

    Science.gov (United States)

    Kurosu, A.; Hayashi, Y.; Wada, K.; Nagaoka, M.

    2011-01-01

    The interstitial nucleus of Cajal (INC) is thought to play an important role in torsional/vertical eye position and head posture, and disorders of the INC induce abnormal ocular movements and head tilt. Our patients with ocular tilt reactions simultaneously also had disturbances in ambulatory balance, yet no reports address the loss of balance control induced by disorders of the INC. We examined the ambulatory disturbances induced by INC lesion. We experienced three patients with ocular movement disorders and abnormal head tilt due to thalamic infarction. We performed ophthalmic examinations on and checked the balance of them. With funduscopy, abnormal cycloduction was seen in the unaffected side and normal cycloduction was observed in the affected side. Nevertheless, Hess charts showed distortions in the visual image of both eyes. They all had disorders of balance control. We tried to treat them using the Bobath approach for improving their ambulatory balance. With subsequent improvements in balance control it was possible for them to take short walks, but it was difficult to make any improvements in their ocular movement. The INC is related to balance control of ambulation and disorders of the INC induce ambulatory disturbances. Cycloduction was only observed in the unaffected side, but Hess charts showed distortions of the visual image in both eyes. Ambulation was briefly improved, but diplopia persisted in these patients. PMID:21769260

  18. Corticothalamic Synaptic Noise as a Mechanism for Selective Attention in Thalamic Neurons

    Science.gov (United States)

    Béhuret, Sébastien; Deleuze, Charlotte; Bal, Thierry

    2015-01-01

    A reason why the thalamus is more than a passive gateway for sensory signals is that two-third of the synapses of thalamocortical neurons are directly or indirectly related to the activity of corticothalamic axons. While the responses of thalamocortical neurons evoked by sensory stimuli are well characterized, with ON- and OFF-center receptive field structures, the prevalence of synaptic noise resulting from neocortical feedback in intracellularly recorded thalamocortical neurons in vivo has attracted little attention. However, in vitro and modeling experiments point to its critical role for the integration of sensory signals. Here we combine our recent findings in a unified framework suggesting the hypothesis that corticothalamic synaptic activity is adapted to modulate the transfer efficiency of thalamocortical neurons during selective attention at three different levels: First, on ionic channels by interacting with intrinsic membrane properties, second at the neuron level by impacting on the input-output gain, and third even more effectively at the cell assembly level by boosting the information transfer of sensory features encoded in thalamic subnetworks. This top-down population control is achieved by tuning the correlations in subthreshold membrane potential fluctuations and is adapted to modulate the transfer of sensory features encoded by assemblies of thalamocortical relay neurons. We thus propose that cortically-controlled (de-)correlation of subthreshold noise is an efficient and swift dynamic mechanism for selective attention in the thalamus. PMID:26733818

  19. Identification of proopiomelanocortin-related peptides in the rostral pars distalis of the pituitary in coelacanth: evolutional implications.

    Science.gov (United States)

    Takahashi, Akiyoshi; Yasuda, Akikazu; Sullivan, Craig V; Kawauchi, Hiroshi

    2003-02-15

    The coelacanth fish, genus Latimeria, flourished during the Devonian Period and is considered among the closest living relatives of tetrapods. It may therefore provide important information on the evolution of fishes into tetrapods. However, little is known about the components of the endocrine system in this fish. Here we describe the structural characterization of pituitary hormones derived from proopiomelanocortin (POMC) in Latimeria chalumnae. We identified alpha-melanocyte-stimulating hormone (MSH), N-Des-acetyl-alpha-MSH, beta-MSH, N-terminal peptide containing gamma-MSH, corticotropin-like intermediate lobe peptide (CLIP), and N-acetyl-beta-endorpin (END) in an extract from the rostral pars distalis of the pituitary by reversed-phase high-performance liquid chromatography, amino acid sequence analysis, and mass spectrometry. The occurrence of three different MSHs and one beta-END indicates that the structural organization of coelacanth POMC is the same as that of lungfish, tetrapods, and primitive ray-finned fish. The coelacanth alpha-MSH is identical to its mammalian counterpart. The coelacanth beta-MSH shows the highest sequence identity with the amphibian counterpart, and gamma-MSH and CLIP show the highest sequence identity with their amphibian and bird counterparts, whereas coelacanth beta-END is most similar to the sturgeon peptide. The coexistence of tetrapod-type and fish-type characteristics in the putative coelacanth POMC molecule reflects the phylogenetic position of this fish. When each hormonal segment was compared between coelacanth, lungfish, and tetrapod, MSH and CLIP of coelacanth were closer to their tetrapod counterparts than those of lungfish, whereas beta-MSH and beta-END of coelacanth are less closely related to their tetrapod counterparts than those of lungfish. gamma-MSH and CLIP may have evolved at a different rate from beta-MSH and beta-END in both the coelacanth and lungfish.

  20. Chronic infusion of lisinopril into hypothalamic paraventricular nucleus modulates cytokines and attenuates oxidative stress in rostral ventrolateral medulla in hypertension

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    Li, Hong-Bao [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Qin, Da-Nian, E-mail: dnqin@stu.edu.cn [Department of Physiology, Shantou University Medical College, Shantou 515041 (China); Ma, Le [Department of Public Health, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Miao, Yu-Wang [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Zhang, Dong-Mei [Department of Physiology, Dalian Medical University, Dalian 116044 (China); Lu, Yan [Department of Clinical Laboratory, Sanaitang Hospital, Lanzhou 730030 (China); Song, Xin-Ai [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Zhu, Guo-Qing [Key Laboratory of Cardiovascular Disease and Molecular Intervention, Department of Physiology, Nanjing Medical University, Nanjing 210029 (China); Kang, Yu-Ming, E-mail: ykang@mail.xjtu.edu.cn [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China)

    2014-09-01

    The hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play a critical role in the generation and maintenance of sympathetic nerve activity. The renin–angiotensin system (RAS) in the brain is involved in the pathogenesis of hypertension. This study was designed to determine whether inhibition of the angiotensin-converting enzyme (ACE) in the PVN modulates cytokines and attenuates oxidative stress (ROS) in the RVLM, and decreases the blood pressure and sympathetic activity in renovascular hypertensive rats. Renovascular hypertension was induced in male Sprague–Dawley rats by the two-kidney one-clip (2K1C) method. Renovascular hypertensive rats received bilateral PVN infusion with ACE inhibitor lisinopril (LSP, 10 μg/h) or vehicle via osmotic minipump for 4 weeks. Mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and plasma proinflammatory cytokines (PICs) were significantly increased in renovascular hypertensive rats. The renovascular hypertensive rats also had higher levels of ACE in the PVN, and lower level of interleukin-10 (IL-10) in the RVLM. In addition, the levels of PICs, the chemokine MCP-1, the subunit of NAD(P)H oxidase (gp91{sup phox}) and ROS in the RVLM were increased in hypertensive rats. PVN treatment with LSP attenuated those changes occurring in renovascular hypertensive rats. Our findings suggest that the beneficial effects of ACE inhibition in the PVN in renovascular hypertension are partly due to modulation cytokines and attenuation oxidative stress in the RVLM. - Highlights: • Chronic ACE inhibition in PVN on renovascular hypertension was investigated. • 2K1C resulted in sympathoexcitation, increased plasma PICs and hypertension. • 2K1C rats had higher levels of cytokines and reactive oxygen species (ROS) in RVLM. • Chronic inhibiting PVN ACE attenuates cytokines and ROS in RVLM in hypertension.

  1. Rostral Ventrolateral Medulla EP3 Receptor Mediates the Sympathoexcitatory and Pressor Effects of Prostaglandin E2 in Conscious Rats.

    Science.gov (United States)

    Rezq, Samar; Abdel-Rahman, Abdel A

    2016-11-01

    Whereas few studies have dealt with the central sympathoexcitatory action of the inflammatory prostanoid prostaglandin E2 (PGE2), there is no information on the expression and cardiovascular function of different PGE2 (EP) receptors in one of the major cardiovascular-regulating nuclei, the rostral ventrolateral medulla (RVLM). The current study aimed at filling this knowledge gap as well as elucidating the implicated molecular mechanisms. To achieve these goals, we showed the expression of EP2, EP3, and EP4 receptors in the RVLM and investigated their cardiovascular roles in conscious rats, ex vivo as well as in cultured PC12 cells. Intra-RVLM PGE2 significantly increased blood pressure and sympathetic dominance (spectral analysis). Studies with selective EP receptor subtype agonists and antagonists showed that these PGE2-evoked responses were only replicated by intra-RVLM activation of the EP3 receptor with its agonist sulprostone. The RVLM of PGE2-treated rats exhibited increases in c-Fos expression and extracellular signal-regulated kinase 1/2 and neuronal nitric oxide synthase phosphorylation along with oxidative stress, and PGE2 increased l-glutamate release in PC12 cells (surrogates of RVLM neurons). Abrogation of the PGE2-evoked pressor and biochemical responses only occurred following EP3 receptor blockade (N-[(5-Bromo-2-methoxyphenyl)sulfonyl]-3-[2-(2-naphthalenylmethyl)phenyl]-2-propenamide, L-798106). These findings suggest the dependence of RVLM PGE2-mediated sympathoexcitation/pressor response on local EP3 receptor signaling in conscious rats, and highlight central EP3 receptor blockade as a potential therapeutic modality for hypertension management. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Responses of neurons in the rostral ventrolateral medulla to whole body rotations: comparisons in decerebrate and conscious cats.

    Science.gov (United States)

    Destefino, V J; Reighard, D A; Sugiyama, Y; Suzuki, T; Cotter, L A; Larson, M G; Gandhi, N J; Barman, S M; Yates, B J

    2011-06-01

    The responses to vestibular stimulation of brain stem neurons that regulate sympathetic outflow and blood flow have been studied extensively in decerebrate preparations, but not in conscious animals. In the present study, we compared the responses of neurons in the rostral ventrolateral medulla (RVLM), a principal region of the brain stem involved in the regulation of blood pressure, to whole body rotations of conscious and decerebrate cats. In both preparations, RVLM neurons exhibited similar levels of spontaneous activity (median of ∼17 spikes/s). The firing of about half of the RVLM neurons recorded in decerebrate cats was modulated by rotations; these cells were activated by vertical tilts in a variety of directions, with response characteristics suggesting that their labyrinthine inputs originated in otolith organs. The activity of over one-third of RVLM neurons in decerebrate animals was altered by stimulation of baroreceptors; RVLM units with and without baroreceptor signals had similar responses to rotations. In contrast, only 6% of RVLM neurons studied in conscious cats exhibited cardiac-related activity, and the firing of just 1% of the cells was modulated by rotations. These data suggest that the brain stem circuitry mediating vestibulosympathetic reflexes is highly sensitive to changes in body position in space but that the responses to vestibular stimuli of neurons in the pathway are suppressed by higher brain centers in conscious animals. The findings also raise the possibility that autonomic responses to a variety of inputs, including those from the inner ear, could be gated according to behavioral context and attenuated when they are not necessary.

  3. "On-" and "off-" cells in the rostral ventromedial medulla of rats held in thermoneutral conditions: are they involved in thermoregulation?

    Science.gov (United States)

    El Bitar, Nabil; Pollin, Bernard; Le Bars, Daniel

    2014-11-01

    In thermal neutral condition, rats display cyclic variations of the vasomotion of the tail and paws, synchronized with fluctuations of blood pressure, heart rate, and core body temperature. "On-" and "off-" cells located in the rostral ventromedial medulla, a cerebral structure implicated in somatic sympathetic drive, 1) exhibit similar spontaneous cyclic activities in antiphase and 2) are activated and inhibited by thermal nociceptive stimuli, respectively. We aimed at evaluating the implication of such neurons in autonomic regulation by establishing correlations between their firing and blood pressure, heart rate, and skin and core body temperature variations. When, during a cycle, a relative high core body temperature was reached, the on-cells were activated and within half a minute, the off-cells and blood pressure were depressed, followed by heart rate depression within a further minute; vasodilatation of the tail followed invariably within ∼3 min, often completed with vasodilatation of hind paws. The outcome was an increased heat loss that lessened the core body temperature. When the decrease of core body temperature achieved a few tenths of degrees, sympathetic activation switches off and converse variations occurred, providing cycles of three to seven periods/h. On- and off-cell activities were correlated with inhibition and activation of the sympathetic system, respectively. The temporal sequence of events was as follows: core body temperature → on-cell → off-cell ∼ blood pressure → heart rate → skin temperature → core body temperature. The function of on- and off-cells in nociception should be reexamined, taking into account their correlation with autonomic regulations. Copyright © 2014 the American Physiological Society.

  4. Role of nitric oxide synthase uncoupling at rostral ventrolateral medulla in redox-sensitive hypertension associated with metabolic syndrome.

    Science.gov (United States)

    Wu, Kay L H; Chao, Yung-Mei; Tsay, Shiow-Jen; Chen, Chen Hsiu; Chan, Samuel H H; Dovinova, Ima; Chan, Julie Y H

    2014-10-01

    Metabolic syndrome (MetS), which is rapidly becoming prevalent worldwide, is long known to be associated with hypertension and recently with oxidative stress. Of note is that oxidative stress in the rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons reside, contributes to sympathoexcitation and hypertension. This study sought to identify the source of tissue oxidative stress in RVLM and their roles in neural mechanism of hypertension associated with MetS. Adult normotensive rats subjected to a high-fructose diet for 8 weeks developed metabolic traits of MetS, alongside increases in sympathetic vasomotor activity and blood pressure. In RVLM of these MetS rats, the tissue level of reactive oxygen species was increased, nitric oxide (NO) was decreased, and mitochondrial electron transport capacity was reduced. Whereas the protein expression of neuronal NO synthase (nNOS) or protein inhibitor of nNOS was increased, the ratio of nNOS dimer/monomer was significantly decreased. Oral intake of pioglitazone or intracisternal infusion of tempol or coenzyme Q10 significantly abrogated all those molecular events in high-fructose diet-fed rats and ameliorated sympathoexcitation and hypertension. Gene silencing of protein inhibitor of nNOS mRNA in RVLM using lentivirus carrying small hairpin RNA inhibited protein inhibitor of nNOS expression, increased the ratio of nNOS dimer/monomer, restored NO content, and alleviated oxidative stress in RVLM of high-fructose diet-fed rats, alongside significantly reduced sympathoexcitation and hypertension. These results suggest that redox-sensitive and protein inhibitor of nNOS-mediated nNOS uncoupling is engaged in a vicious cycle that sustains the production of reactive oxygen species in RVLM, resulting in sympathoexcitation and hypertension associated with MetS.

  5. Expression of the M3 Muscarinic Receptor on Orexin Neurons that Project to the Rostral Ventrolateral Medulla.

    Science.gov (United States)

    Dai, Yu-Wen E; Lee, Yen-Hsien; Chen, Jennifer Y S; Lin, Yen-Kuang; Hwang, Ling-Ling

    2016-05-01

    Activation of central cholinergic receptors causes a pressor response in rats, and the hypothalamus is important for this response. Projections from hypothalamic orexin neurons to the rostral ventrolateral medulla (RVLM) are involved in sympatho-excitation of the cardiovascular system. A small population of orexin neurons is regulated by cholinergic inputs through M3 muscarinic acetylcholine receptor (M3 R). To elucidate whether the M3 R on orexin neurons is involved in cardiosympathetic regulation through the RVLM, we examined the presence of the M3 R on retrograde-labeled RVLM-projecting orexin neurons. The retrograde tracer was unilaterally injected into the RVLM. Within the hypothalamus, retrograde-labeled neurons were located predominantly ipsilateral to the injection side. In the anterior hypothalamus (-1.5 to -2.3 mm to the bregma), retrograde-labeled neurons were densely distributed in the paraventricular nuclei and scattered in the retrochiasmatic area. At -2.3 to -3.5 mm from the bregma, labeled neurons were located in the regions where orexin neurons were situated, that is, the tuberal lateral hypothalamic area, perifornical area, and dorsomedial nuclei. Very few retrograde-labeled neurons were observed in the hypothalamus at -3.5 to -4.5 mm from the bregma. About 19.5% ± 1.6% of RVLM-projecting neurons in the tuberal hypothalamus were orexinergic. The M3 R was present on 18.7% ± 3.0% of RVLM-projecting orexin neurons. Injection of a muscarinic agonist, oxotremorine, in the perifornical area resulted in a pressor response, which was attenuated by a pretreatment of atropine. We conclude that cholinergic inputs to orexin neurons may be involved in cardiosympathetic regulation through the M3 R on the orexin neurons that directly project to the RVLM.

  6. Bilateral thalamic stroke due to occlusion of the artery of Percheron in a patient with patent foramen ovale: a case report

    Directory of Open Access Journals (Sweden)

    López-Serna Raúl

    2009-09-01

    Full Text Available Abstract Introduction Bilateral thalamic infarcts are rare presentations of stroke. They are the result of a complex combination of risk factors and a predisposing vessel distribution. The artery of Percheron, characterized by a single arterial trunk that irrigates both paramedian thalamic regions, can be occluded as a result of embolic diseases leading to bilateral paramedian thalamic infarcts. Clinical and image findings of this uncommon form of posterior circulation infarct are presented along with their anatomic and pathophysiologic correlates. Case presentation A 27-year-old Mexican man with no relevant medical history was admitted to hospital after he was found deeply stuporous. On admission, an urgent neuroimaging protocol for stroke, including magnetic resonance imaging and magnetic resonance imaging angiography, was performed. The scans revealed symmetric bilateral hyperintense paramedian thalamic lesions consistent with acute ischemic events. The posterior circulation was patent including the tip of the basilar artery and both posterior cerebral arteries, making the case compatible with occlusion of the artery of Percheron. Further evaluation with an aim to define the etiology revealed a patent foramen ovale as the cause of embolism. Conclusion Bilateral thalamic infarcts are unusual presentations of posterior circulation stroke; once they are diagnosed by an adequate neuroimaging protocol, a further evaluation to define the cause is necessary. Cardioembolism should always be considered in relatively young patients. A complete evaluation should be conducted by an interdisciplinary team including neurologists, cardiologists and neurosurgeons.

  7. Neurochemical pathways that converge on thalamic trigeminovascular neurons: potential substrate for modulation of migraine by sleep, food intake, stress and anxiety.

    Directory of Open Access Journals (Sweden)

    Rodrigo Noseda

    Full Text Available Dynamic thalamic regulation of sensory signals allows the cortex to adjust better to rapidly changing behavioral, physiological and environmental demands. To fulfill this role, thalamic neurons must themselves be subjected to constantly changing modulatory inputs that originate in multiple neurochemical pathways involved in autonomic, affective and cognitive functions. Our overall goal is to define an anatomical framework for conceptualizing how a 'decision' is made on whether a trigeminovascular thalamic neuron fires, for how long, and at what frequency. To begin answering this question, we determine which neuropeptides/neurotransmitters are in a position to modulate thalamic trigeminovascular neurons. Using a combination of in-vivo single-unit recording, juxtacellular labeling with tetramethylrhodamine dextran (TMR and in-vitro immunohistochemistry, we found that thalamic trigeminovascular neurons were surrounded by high density of axons containing biomarkers of glutamate, GABA, dopamine and serotonin; moderate density of axons containing noradrenaline and histamine; low density of axons containing orexin and melanin concentrating hormone (MCH; but not axons containing CGRP, serotonin 1D receptor, oxytocin or vasopressin. In the context of migraine, the findings suggest that the transmission of headache-related nociceptive signals from the thalamus to the cortex may be modulated by opposing forces (i.e., facilitatory, inhibitory that are governed by continuous adjustments needed to keep physiological, behavioral, cognitive and emotional homeostasis.

  8. Oscillatory synchrony between head direction cells recorded bilaterally in the anterodorsal thalamic nuclei.

    Science.gov (United States)

    Butler, William N; Taube, Jeffrey Steven

    2017-03-01

    The head direction (HD) circuit is a complex, interconnected network of brain regions ranging from the brainstem to the cortex. Recent work found that HD cells co-recorded ipsilaterally in the anterodorsal nucleus (ADN) of the thalamus displayed coordinated firing patterns. A high frequency oscillation pattern (130-160 Hz) was visible in the cross-correlograms of these HD cell pairs. Spectral analysis further found that the power of this oscillation was greatest at 0 ms and decreased at greater lags, and demonstrated that there was greater synchrony between HD cells with similar tunings. Here, we demonstrate that the same high frequency synchrony exists in HD cell pairs recorded contralaterally from one another in the bilateral ADN. When we examined the cross-correlograms of HD cells that were co-recorded bilaterally we observed the same high frequency (~150-200 Hz) oscillatory relationship. The strength of this synchrony was similar to the synchrony seen in ipsilateral HD cell pairs, and the degree of synchrony in each cross-correlogram was dependent on the difference in tuning between the two cells. Additionally, the frequency rate of this oscillation appeared to be independent of the firing rates of the two cross-correlated cells. Taken together, these results imply that the left and right thalamic HD network are functionally related, despite an absence of direct anatomical projections. However, anatomical tracing has found that each of the lateral mammillary nuclei (LMN) project bilaterally to both of the ADN, suggesting the LMN may be responsible for the functional connectivity observed between the two ADN.

  9. Thalamic microinfusion of antibody to a voltage-gated potassium channel restores consciousness during anesthesia.

    Science.gov (United States)

    Alkire, Michael T; Asher, Christopher D; Franciscus, Amanda M; Hahn, Emily L

    2009-04-01

    The Drosophila Shaker mutant fruit-fly, with its malfunctioning voltage-gated potassium channel, exhibits anesthetic requirements that are more than twice normal. Shaker mutants with an abnormal Kv1.2 channel also demonstrate significantly reduced sleep. Given the important role the thalamus plays in both sleep and arousal, the authors investigated whether localized central medial thalamic (CMT) microinfusion of an antibody designed to block the pore of the Kv1.2 channel might awaken anesthetized rats. Male Sprague-Dawley rats were implanted with a cannula aimed at the CMT or lateral thalamus. One week later, unconsciousness was induced with either desflurane (3.6 +/- 0.2%; n = 55) or sevoflurane (1.2 +/- 0.1%; n = 51). Arousal effects of a single 0.5-microl infusion of Kv1.2 potassium channel blocking antibody (0.1- 0.2 mg/ml) or a control infusion of Arc-protein antibody (0.2 mg/ml) were then determined. The Kv1.2 antibody, but not the control antibody, temporarily restored consciousness in 17% of all animals and in 75% of those animals where infusions occurred within the CMT (P Consciousness returned on average (+/- SD) 170 +/- 99 s after infusion and lasted a median time of 398 s (interquartile range: 279-510 s). Temporary seizures, without apparent consciousness, predominated in 33% of all animals. These findings support the idea that the CMT plays a role in modulating levels of arousal during anesthesia and further suggest that voltage-gated potassium channels in the CMT may contribute to regulating arousal or may even be relevant targets of anesthetic action.

  10. Specific circular organization of the neurons of human interthalamic adhesion and of periventricular thalamic region.

    Science.gov (United States)

    Laslo, Puskas; Slobodan, Malobabić; Nela, Puskas; Milos, Malis; Rade, Popović; Tatjana, Ille

    2005-05-01

    Interthalamic adhesion between the medial surfaces of the left and right thalamus is a variable structure and contains the midline thalamic nuclei, which are not much developed in humans. The research has been done on 6 human brains obtained during routine autopsy (age 45 to 65; 4 male and 2 female). Every tenth 10 microm thick frontal section was stained according to Klüver-Barrera method. In all cases the authors found a specific organization of certain groups of neurons within the interthalamic adhesion (IA) in form of circles on frontal sections. These circular groups were present on all sections but only 1-2 in each. The larger mean diameter of these circular arrangements was R = 229.4 microm, and smaller was r = 203.1 microm. These circular groups within the human IA were formed in average by 7.29 neurons. In periventricular region (PVR) of thalamus similar circular groups of neurons also were present in all cases as in IA. These neuronal groups in PVR were of smaller size than in the IA, with larger mean diameter R = 201.4, smaller mean diameter r = 181.2 microm and they contained fewer neurons, 6.69 on average. All three values (both diameters of circular arrangements, and number of neurons forming them) were significantly smaller in PVR (p < .01). Morphological types and sizes of neurons in both investigated structures (IA and PV) were not different. The circular neuronal groups in IA were formed in 61% of fusiform neurons and in PVR in 48% of fusiform neurons. According to their subependymal localization, size and form, these circular groups can represent in vivo correlates of neurospheres.

  11. Cell type-specific thalamic innervation in a column of rat vibrissal cortex.

    Science.gov (United States)

    Meyer, Hanno S; Wimmer, Verena C; Hemberger, Mike; Bruno, Randy M; de Kock, Christiaan P J; Frick, Andreas; Sakmann, Bert; Helmstaedter, Moritz

    2010-10-01

    This is the concluding article in a series of 3 studies that investigate the anatomical determinants of thalamocortical (TC) input to excitatory neurons in a cortical column of rat primary somatosensory cortex (S1). We used viral synaptophysin-enhanced green fluorescent protein expression in thalamic neurons and reconstructions of biocytin-labeled cortical neurons in TC slices to quantify the number and distribution of boutons from the ventral posterior medial (VPM) and posteromedial (POm) nuclei potentially innervating dendritic arbors of excitatory neurons located in layers (L)2-6 of a cortical column in rat somatosensory cortex. We found that 1) all types of excitatory neurons potentially receive substantial TC input (90-580 boutons per neuron); 2) pyramidal neurons in L3-L6 receive dual TC input from both VPM and POm that is potentially of equal magnitude for thick-tufted L5 pyramidal neurons (ca. 300 boutons each from VPM and POm); 3) L3, L4, and L5 pyramidal neurons have multiple (2-4) subcellular TC innervation domains that match the dendritic compartments of pyramidal cells; and 4) a subtype of thick-tufted L5 pyramidal neurons has an additional VPM innervation domain in L4. The multiple subcellular TC innervation domains of L5 pyramidal neurons may partly explain their specific action potential patterns observed in vivo. We conclude that the substantial potential TC innervation of all excitatory neuron types in a cortical column constitutes an anatomical basis for the initial near-simultaneous representation of a sensory stimulus in different neuron types.

  12. Synaptic responsiveness of cortical and thalamic neurones during various phases of slow sleep oscillation in cat.

    Science.gov (United States)

    Timofeev, I; Contreras, D; Steriade, M

    1996-01-01

    1. The fluctuations during various phases of the slow sleep oscillation (< 1 Hz) in synaptic responsiveness of motor cortical (Cx), thalamic reticular (RE) and thalamocortical (TC) neurones were investigated intracellularly in cats under ketamine-xylazine anaesthesia. Orthodromic responses to stimuli applied to brachium conjunctivum (BC) axons and corticothalamic pathways were studied. The phases of slow oscillation consist of a long-hyperpolarized, followed by a sharp depth-negative EEG deflection and a series of faster waves that are associated with the depolarization of Cx and RE neurones, while TC cells display a sequence of IPSPs within the spindle frequency. 2. BC-evoked bisynaptic excitatory postsynaptic potentials (EPSPs) in Cx and RE neurones were drastically reduced in amplitude during the long-lasting hyperpolarization and the early part of the depolarizing phase. By contrast, the BC-evoked monosynaptic EPSPs of TC cells were not diminished during the depth-positive EEG wave, but the hyperpolarization during this phase of the slow oscillation prevented TC neurones transferring prethalamic signals to the cortex. 3. At variance with the diminished bisynaptic EPSPs evoked in response to BC stimuli during the long-lasting hyperpolarization, Cx-evoked monosynaptic EPSPs in Cx cells increased linearly with hyperpolarization during this phase of the slow oscillation. Similarly, the amplitudes of Cx-evoked EPSPs in RE and TC cells were not diminished during the long-lasting hyperpolarization. 4. The diminished responsiveness of Cx and RE neurones to prethalamic volleys during the long-lasting hyperpolarization is attributed to gating processes at the level of TC cells that, because of their hyperpolarization, do not transfer prethalamic information to further relays. PMID:8814620

  13. Effects of Anterior Thalamic Nucleus Deep Brain Stimulation in Chronic Epileptic Rats

    Science.gov (United States)

    Amorim, Beatriz; Cavarsan, Clarissa; Miranda, Maisa Ferreira; Aarão, Mayra C.; Madureira, Ana Paula; Rodrigues, Antônio M.; Nobrega, José N.; Mello, Luiz E.; Hamani, Clement

    2014-01-01

    Deep brain stimulation (DBS) has been investigated for the treatment of epilepsy. In rodents, an increase in the latency for the development of seizures and status epilepticus (SE) has been reported in different animal models but the consequences of delivering stimulation to chronic epileptic animals have not been extensively addressed. We study the effects of anterior thalamic nucleus (AN) stimulation at different current intensities in rats rendered epileptic following pilocarpine (Pilo) administration. Four months after Pilo-induced SE, chronic epileptic rats were bilaterally implanted with AN electrodes or had sham-surgery. Stimulation was delivered for 6 h/day, 5 days/week at 130 Hz, 90 µsec. and either 100 µA or 500 µA. The frequency of spontaneous recurrent seizures in animals receiving stimulation was compared to that recorded in the preoperative period and in rats given sham treatment. To investigate the effects of DBS on hippocampal excitability, brain slices from animals receiving AN DBS or sham surgery were studied with electrophysiology. We found that rats treated with AN DBS at 100 µA had a 52% non-significant reduction in the frequency of seizures as compared to sham-treated controls and 61% less seizures than at baseline. Animals given DBS at 500 µA had 5.1 times more seizures than controls and a 2.8 fold increase in seizure rate as compared to preoperative values. In non-stimulated controls, the average frequency of seizures before and after surgery remained unaltered. In vitro recordings have shown that slices from animals previously given DBS at 100 µA had a longer latency for the development of epileptiform activity, shorter and smaller DC shifts, and a smaller spike amplitude compared to non-stimulated controls. In contrast, a higher spike amplitude was recorded in slices from animals given AN DBS at 500 µA. PMID:24892420

  14. Thalamic DBS with a constant-current device in essential tremor: A controlled clinical trial.

    Science.gov (United States)

    Wharen, Robert E; Okun, Michael S; Guthrie, Barton L; Uitti, Ryan J; Larson, Paul; Foote, Kelly; Walker, Harrison; Marshall, Frederick J; Schwalb, Jason; Ford, Blair; Jankovic, Joseph; Simpson, Richard; Dashtipour, Khashayar; Phibbs, Fenna; Neimat, Joseph S; Stewart, R Malcolm; Peichel, DeLea; Pahwa, Rajesh; Ostrem, Jill L

    2017-07-01

    This study of thalamic deep brain stimulation (DBS) investigated whether a novel constant-current device improves tremor and activities of daily living (ADL) in patients with essential tremor (ET). A prospective, controlled, multicenter study was conducted at 12 academic centers. We investigated the safety and efficacy of unilateral and bilateral constant-current DBS of the ventralis intermedius (VIM) nucleus of the thalamus in patients with essential tremor whose tremor was inadequately controlled by medications. The primary outcome measure was a rater-blinded assessment of the change in the target limb tremor score in the stimulation-on versus stimulation-off state six months following surgery. Multiple secondary outcomes were assessed at one-year follow-up, including motor, mood, and quality-of-life measures. 127 patients were implanted with VIM DBS. The blinded, primary outcome variable (n = 76) revealed a mean improvement of 1.25 ± 1.26 points in the target limb tremor rating scale (TRS) score in the arm contralateral to DBS (p < 0.001). Secondary outcome variables at one year revealed significant improvements (p ≤ 0.001) in quality of life, depression symptoms, and ADL scores. Forty-seven patients had a second contralateral VIM-DBS, and this group demonstrated reduction in second-sided tremor at 180 days (p < 0.001). Serious adverse events related to the surgery included infection (n = 3), intracranial hemorrhage (n = 3), and device explantation (n = 3). Unilateral and bilateral constant-current VIM DBS significantly improves upper extremity tremor, ADL, quality of life, and depression in patients with severe ET. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Decreased striatal and enhanced thalamic dopaminergic responsivity in detoxified cocaine abusers

    Energy Technology Data Exchange (ETDEWEB)

    Volkow, N.D.; Wang, G.J.; Fowler, J.S. [Brookhaven National Lab., Stony Brook, NY (United States)] [and others

    1997-05-01

    It has been hypothesized that cocaine addiction could result from decreased brain dopamine (DA) function. However, little is known about changes in (DA) neurotransmission in human cocaine addiction. We used PET and [C-11]raclopride, a DA D2 receptor ligand sensitive to competition with endogenous DA, to measure relative changes in extracellular DA induced by methylphenidate (MP) in 20 cocaine abusers (3-6 weeks after cocaine discontinuation) and 23 controls. MP did not affect the transport of [C-11]raclopride from blood to brain (K1); however it induced a significant reduction in DA D2 receptor availability (Bmax/Kd) in striatum. The magnitude of ND-induced changes in striatal [C-11]raclopride binding were significantly larger in controls (21 + 13% change from baseline) than in cocaine abusers (9 {+-} 13 %) (ANOVA p < 0.005). In cocaine abusers, but not in controls, MP also decreased Bmax/Kd values in thalamus (29 {+-} 35 %) (ANOVA p < 0.005). There were no differences in plasma MP concentration between the groups. In striatum MP-induced changes in Bmax/Kd were significantly correlated with MP-induced changes in self reports of restlessness (r = 0.49, df 42, p < 0.002). In thalamus MP-induced changes in Bmax/Kd were significantly correlated with ND-induced changes in self reports of cocaine craving (r = 0.57, df 42, p < 0.0001). These results are compatible with a decrease in striatal DA brain function in cocaine abusers. They also suggest a participation of thalamic DA pathways in cocaine addiction.

  16. Imidazoline receptors associated with noradrenergic terminals in the rostral ventrolateral medulla mediate the hypotensive responses of moxonidine but not clonidine.

    Science.gov (United States)

    Chan, C K S; Burke, S L; Zhu, H; Piletz, J E; Head, G A

    2005-01-01

    We determined whether the cardiovascular actions of central anti-hypertensive agents clonidine and moxonidine are dependent on noradrenergic or serotonergic innervation of the rostral ventrolateral medulla (RVLM) in conscious rabbits. 6-Hydroxydopamine (6-OHDA) or 5,6-dihydroxytriptamine (5,6-DHT) was injected into the RVLM to deplete noradrenergic and serotonergic terminals respectively. One, 2 and 4 weeks later, responses to fourth ventricular (4V) clonidine (0.65 microg/kg) and moxonidine (0.44 microg/kg) were examined. Destruction of noradrenergic pathways in the RVLM by 6-OHDA reduced the hypotensive response to 4V moxonidine to 62%, 47% and 60% of that observed in vehicle treated rabbits at weeks 1, 2 and 4 respectively. The moxonidine induced bradycardia was similarly attenuated (to 46% of vehicle). Conversely, 6-OHDA had no effect on the hypotensive or bradycardic effects of 4V clonidine. Efaroxan (I(1)-imidazoline receptor/alpha(2)-adrenoceptor antagonist; 3.5, 11, 35 microg/kg) and 2-methoxyidazoxan (alpha(2)-adrenoceptor antagonist; 0.3, 0.9, 3 microg/kg) equally reversed the hypotension to 4V clonidine, suggesting a mainly alpha(2)-adrenoceptor mechanism. Efaroxan preferentially reversed responses to moxonidine in both vehicle and 5,6-DHT groups and in the 1st week after 6-OHDA, suggesting a mechanism involving mainly I(1)-imidazoline receptors. This selectivity was subsequently lost in the 2nd and 4th weeks when the remaining hypotension was mainly mediated by alpha(2)-adrenoceptors. Depletion of serotonergic terminals did not alter the responses to either agonist nor did it change the relative effectiveness of the antagonists. Western blots of RVLM tissues probed with imidazoline and alpha(2)-adrenoceptor antisera showed a pattern of bands close to that reported in other species. The main effect of 6-OHDA was an 18% lower level of the 42 kDa imidazoline protein (P<0.05). We conclude that the hypotensive and bradycardic actions of moxonidine but not

  17. Differential cardiovascular responses to blockade of nNOS or iNOS in rostral ventrolateral medulla of the rat

    Science.gov (United States)

    Chan, Samuel H H; Wang, Ling-Lin; Wang, Shu-Huei; Chan, Julie Y H

    2001-01-01

    We investigated the contribution of neuronal or inducible nitric oxide synthase (nNOS or iNOS) at the rostral ventrolateral medulla (RVLM) to central cardiovascular regulation by endogenous nitric oxide (NO), using Sprague-Dawley rats anaesthetized and maintained with propofol.Microinjection bilaterally into the RVLM of a NO trapping agent, carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-l-oxy-l-3-oxide (10, 50 or 100 nmoles) resulted in significant hypotension and bradycardia.Similar application of a selective antagonist of nNOS, 7-nitroindazole (1, 2.5 or 5 pmoles), or selective antagonists of iNOS, aminoguanidine (125, 250 or 500 pmoles), N6-(l-iminoethyl)-L-lysine (250 pmoles) or S-methylisothiourea (250 pmoles), induced respectively a reduction or an enhancement in systemic arterial pressure, heart rate and power density of the vasomotor components in the spectrum of arterial blood pressure signals, the experimental index for sympathetic neurogenic vasomotor tone.Both hypotension and bradycardia induced by the NO precursor, L-arginine (100 nmoles), were significantly blunted when aminoguanidine (250 pmoles) was co-microinjected bilaterally into the RVLM. On the other hand, co-administered 7-nitroindazole (2.5 pmoles) was ineffective.Whereas low doses of S-nitro-N-acetylpenicillamine (0.25 or 0.5 nmoles) elicited hypertension and tachycardia, high doses of this non-nitrate NO donor (5 nmoles) induced hypotension and bradycardia.Reverse transcription – polymerase chain reaction analysis revealed that both iNOS and nNOS mRNA were expressed in the ventrolateral medulla.We conclude that the prevalence of nNOS over iNOS activity at the RVLM and the associated dominance of sympathoexcitation over sympathoinhibition may underlie the maintenance of sympathetic vasomotor outflow and stable systemic arterial pressure by the endogenous NO. PMID:11399678

  18. Orexins depolarize rostral ventrolateral medulla neurons and increase arterial pressure and heart rate in rats mainly via orexin 2 receptors.

    Science.gov (United States)

    Huang, Shang-Cheng; Dai, Yu-Wen E; Lee, Yen-Hsien; Chiou, Lih-Chu; Hwang, Ling-Ling

    2010-08-01

    An injection of orexin A or B into the cisterna magna or the rostral ventrolateral medulla (RVLM), where bulbospinal vasomotor neurons are located, elevated arterial pressure (AP) and heart rate (HR). We examined how orexins affected RVLM neurons to regulate cardiovascular functions by using in vitro recordings of neuronal activity of the RVLM and in vivo measurement of cardiovascular functions in rats. Orexin A and B concentration-dependently depolarized RVLM neurons. At 100 nM, both peptides excited 42% of RVLM neurons. Tetrodotoxin failed to block orexin-induced depolarization. In the presence of N-(2-methyl-6-benzoxazolyl)-N'-1, 5-naphthyridin-4-yl urea (SB-334867), an orexin 1 receptor (OX(1)R) antagonist, orexin A depolarized 42% of RVLM neurons with a smaller, but not significantly different, amplitude (4.9 +/- 0.8 versus 7.2 +/- 1.1 mV). In the presence of (2S)-1- (3,4-dihydro-6,7-dimethoxy-2(1H)-isoquinolinyl)-3,3-dimethyl-2-[(4-pyridinylmethyl)amino]-1-butanone hydrochloride (TCS OX2 29), an orexin 2 receptor (OX(2)R) antagonist, orexin A depolarized 25% of RVLM neurons with a significantly smaller amplitude (1.7 +/- 0.5 mV). Coapplication of both antagonists completely eliminated orexin A-induced depolarization. An OX(2)R agonist, [Ala(11),D-Leu(15)]-orexin B, concentration-dependently depolarized RVLM neurons. Regarding neuronal phenotypes, orexins depolarized 88% of adrenergic, 43% of nonadrenergic, and 36 to 41% of rhythmically firing RVLM neurons. Intracisternal TCS OX2 29 (3 and 10 nmol) suppressed intracisternal orexin A-induced increases of AP and HR, whereas intracisternal SB-334867 (3 and 10 nmol) had no effect on the orexin A-induced increase of HR but suppressed the orexin A-induced pressor response at 10 nmol. We concluded that orexins directly excite RVLM neurons, which include bulbospinal vasomotor neurons, and regulate cardiovascular function mainly via the OX(2)R, with a smaller contribution from the OX(1)R.

  19. Orexin in Rostral Hotspot of Nucleus Accumbens Enhances Sucrose 'Liking' and Intake but Scopolamine in Caudal Shell Shifts 'Liking' Toward 'Disgust' and 'Fear'.

    Science.gov (United States)

    Castro, Daniel C; Terry, Rachel A; Berridge, Kent C

    2016-07-01

    The nucleus accumbens (NAc) contains a hedonic hotspot in the rostral half of medial shell, where opioid agonist microinjections are known to enhance positive hedonic orofacial reactions to the taste of sucrose ('liking' reactions). Within NAc shell, orexin/hypocretin also has been reported to stimulate food intake and is implicated in reward, whereas blockade of muscarinic acetylcholine receptors by scopolamine suppresses intake and may have anti-reward effects. Here, we show that NAc microinjection of orexin-A in medial shell amplifies the hedonic impact of sucrose taste, but only within the same anatomically rostral site, identical to the opioid hotspot. By comparison, at all sites throughout medial shell, orexin microinjections stimulated 'wanting' to eat, as reflected by increases in intake of palatable sweet chocolates. At NAc shell sites outside the hotspot, orexin selectively enhanced 'wanting' to eat without enhancing sweetness 'liking' reactions. In contrast, microinjections of the antagonist scopolamine at all sites in NAc shell suppressed sucrose 'liking' reactions as well as suppressing intake of palatable food. Conversely, scopolamine increased aversive 'disgust' reactions elicited by bitter quinine at all NAc shell sites. Finally, scopolamine microinjections localized to the caudal half of medial shell additionally generated a fear-related anti-predator reaction of defensive treading and burying directed toward the corners of the transparent chamber. Together, these results confirm a rostral hotspot in NAc medial shell as a unique site for orexin induction of hedonic 'liking' enhancement, similar to opioid enhancement. They also reveal distinct roles for orexin and acetylcholine signals in NAc shell for hedonic reactions and motivated behaviors.

  20. Prognosis of thalamic hemorrhage with special reference to the level of consciousness and CT findings on admission

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Toshimasa; Tanahashi, Norio; Nara, Masaharu; Takenaka, Nobuo (Ashikaga Red Cross Hospital, Tochigi (Japan))

    1991-04-01

    The prognosis of thalamic hemorrhage was studied on the basis of neurological gradings on admission, mode of extension and hematoma size on brain CT. The subjects were 126 patients with thalamic hemorrhage who were admitted to Ashikaga Red Cross Hospital during the past ten years. Among the subjects, 120 patients (ages 64{+-}10 yr; mean {+-}SD) were treated with conservative therapy, and 6 patients (ages 59{+-}10 yr) with surgical therapy (ventricular drainage). Brain CT scans were done within 48 hours after onset in all patients. Neurological gradings, brain CT classification and prognosis were investigated according to the criteria of the Japanese Conference on Surgery for Cerebral Stroke. The results of conservative therapy were as follows: (1) In the grade I group on the neurological gradings, 29 of the 39 patients (74%) recovered to full work or an independent life, and none of them died. In the grade IV and V groups, mortality rate was 86%. (2) The prognosis was more unfavorable in type III than in types I and II on the CT classification. Twenty-six of the 36 patients (73%) with type I-a recovered to full work or an independent life. Twenty-five of the 34 patients (74%) with the type III-b died. (3) Only 4 of the 75 patients (5%) with less than 10 ml of hematoma volume died. In contrast, all 14 patients with more than 25 ml of hematoma volume died. (4) The mortality rate among patients with ventricular rupture (47%) was significantly higher than that among patients without ventricular rupture (2%) (p<0.001). (5) The mortality rate of patients with acute hydrocephalus (83%) was significantly higher than that of patients without acute hydrocephalus (20%) (p<0.001). From the above results, it is suggested that neurological grading, brain CT classification, hematoma volume, ventricular rupture and acute hydrocephalus are important prognostic factors for thalamic hemorrhage. (author).

  1. Modulation by extracellular pH of low- and high-voltage-activated calcium currents of rat thalamic relay neurons.

    Science.gov (United States)

    Shah, M J; Meis, S; Munsch, T; Pape, H C

    2001-03-01

    The effects of changes in the extracellular pH (pH(o)) on low-voltage- (LVA) and high-voltage- (HVA) activated calcium currents of acutely isolated relay neurons of the ventrobasal thalamic complex (VB) were examined using the whole cell patch-clamp technique. Modest extracellular alkalinization (pH 7.3 to 7.7) reversibly enlarged LVA calcium currents by 18.6 +/- 3.2% (mean +/- SE, n = 6), whereas extracellular acidification (pH 7.3 to 6.9) decreased the current by 24.8 +/- 3.1% (n = 9). Normalized current amplitudes (I/I(7.3)) fitted as a function of pH(o) revealed an apparent pK(a) of 6.9. Both, half-maximal activation voltage and steady-state inactivation were significantly shifted to more negative voltages by 2-4 mV on extracellular alkalinization and to more positive voltages by 2-3 mV on extracellular acidification, respectively. Recovery from inactivation of LVA calcium currents was not significantly affected by changes in pH(o). In contrast, HVA calcium currents were less sensitive to changes in pH(o). Although extracellular alkalinization increased maximal HVA current by 6.0 +/- 2.0% (n = 7) and extracellular acidification decreased it by 11.9 +/- 0.02% (n = 11), both activation and steady-state inactivation were only marginally affected by the moderate changes in pH(o) used in the present study. The results show that calcium currents of thalamic relay neurons exhibit different pH(o) sensitivity. Therefore activity-related extracellular pH transients might selectively modulate certain aspects of the electrogenic behavior of thalamic relay neurons.

  2. Connectivity-based parcellation of the thalamus explains specific cognitive and behavioural symptoms in patients with bilateral thalamic infarct.

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    Laura Serra

    Full Text Available A novel approach based on diffusion tractography was used here to characterise the cortico-thalamic connectivity in two patients, both presenting with an isolated bilateral infarct in the thalamus, but exhibiting partially different cognitive and behavioural profiles. Both patients (G.P. and R.F. had a pervasive deficit in episodic memory, but only one of them (R.F. suffered also from a dysexecutive syndrome. Both patients had an MRI scan at 3T, including a T1-weighted volume. Their lesions were manually segmented. T1-volumes were normalised to standard space, and the same transformations were applied to the lesion masks. Nineteen healthy controls underwent a diffusion-tensor imaging (DTI scan. Their DTI data were normalised to standard space and averaged. An atlas of Brodmann areas was used to parcellate the prefrontal cortex. Probabilistic tractography was used to assess the probability of connection between each voxel of the thalamus and a set of prefrontal areas. The resulting map of corticothalamic connections was superimposed onto the patients' lesion masks, to assess whether the location of the thalamic lesions in R.F. (but not in G. P. implied connections with prefrontal areas involved in dysexecutive syndromes. In G.P., the lesion fell within areas of the thalamus poorly connected with prefrontal areas, showing only a modest probability of connection with the anterior cingulate cortex (ACC. Conversely, R.F.'s lesion fell within thalamic areas extensively connected with the ACC bilaterally, with the right dorsolateral prefrontal cortex, and with the left supplementary motor area. Despite a similar, bilateral involvement of the thalamus, the use of connectivity-based segmentation clarified that R.F.'s lesions only were located within nuclei highly connected with the prefrontal cortical areas, thus explaining the patient's frontal syndrome. This study confirms that DTI tractography is a useful tool to examine in vivo the effect of focal

  3. Differential changes in thalamic and cortical excitatory synapses onto striatal spiny projection neurons in a Huntington disease mouse model.

    Science.gov (United States)

    Kolodziejczyk, Karolina; Raymond, Lynn A

    2016-02-01

    Huntington disease (HD), a neurodegenerative disorder caused by CAG repeat expansion in the gene encoding huntingtin, predominantly affects the striatum, especially the spiny projection neurons (SPN). The striatum receives excitatory input from cortex and thalamus, and the role of the former has been well-studied in HD. Here, we report that mutated huntingtin alters function of thalamostriatal connections. We used a novel thalamostriatal (T-S) coculture and an established corticostriatal (C-S) coculture, generated from YAC128 HD and WT (FVB/NJ background strain) mice, to investigate excitatory neurotransmission onto striatal SPN. SPN in T-S coculture from WT mice showed similar mini-excitatory postsynaptic current (mEPSC) frequency and amplitude as in C-S coculture; however, both the frequency and amplitude were significantly reduced in YAC128 T-S coculture. Further investigation in T-S coculture showed similar excitatory synapse density in WT and YAC128 SPN dendrites by immunostaining, suggesting changes in total dendritic length or probability of release as possible explanations for mEPSC frequency changes. Synaptic N-methyl-D-aspartate receptor (NMDAR) current was similar, but extrasynaptic current, associated with cell death signaling, was enhanced in YAC128 SPN in T-S coculture. Employing optical stimulation of cortical versus thalamic afferents and recording from striatal SPN in brain slice, we found increased glutamate release probability and reduced AMPAR/NMDAR current ratios in thalamostriatal synapses, most prominently in YAC128. Enhanced extrasynaptic NMDAR current in YAC128 SPN was apparent with both cortical and thalamic stimulation. We conclude that thalamic afferents to the striatum are affected early, prior to an overt HD phenotype; however, changes in NMDAR localization in SPN are independent of the source of glutamatergic input.

  4. Reduced thalamic volume in men with antisocial personality disorder or schizophrenia and a history of serious violence and childhood abuse.

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    Kumari, V; Gudjonsson, G H; Raghuvanshi, S; Barkataki, I; Taylor, P; Sumich, A; Das, K; Kuipers, E; Ffytche, D H; Das, M

    2013-05-01

    Violent behaviour has been associated with presence of certain mental disorders, most notably antisocial personality disorder (ASPD) and schizophrenia, childhood abuse, and multiple brain abnormalities. This study examined for the first time, to the authors' knowledge, the role of psychosocial deprivation (PSD), including childhood physical and sexual abuse, in structural brain volumes of violent individuals with ASPD or schizophrenia. Fifty-six men (26 with ASPD or schizophrenia and a history of serious violence, 30 non-violent) underwent magnetic resonance imaging and were assessed on PSD. Stereological volumetric brain ratings were examined for group differences and their association with PSD ratings. PSD-brain associations were examined further using voxel-based-morphometry. The findings revealed: reduced thalamic volume in psychosocially-deprived violent individuals, relative to non-deprived violent individuals and healthy controls; negative association between thalamic volume and abuse ratings (physical and sexual) in violent individuals; and trend-level negative associations between PSD and hippocampal and prefrontal volumes in non-violent individuals. The voxel-based-morphometry analysis detected a negative association between PSD and localised grey matter volumes in the left inferior frontal region across all individuals, and additionally in the left middle frontal and precentral gyri in non-violent individuals. Violent mentally-disordered individuals with PSD, relative to those with no or minimal PSD, suffer from an additional brain deficit, i.e., reduced thalamic volume; this may affect sensory information processing, and have implications for management, of these individuals. PSD may have a stronger relationship with volumetric loss of stress-linked regions, namely the frontal cortex, in non-violent individuals. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Unilateral asterixis, thalamic astasia and vertical one and half syndrome in a unilateral posterior thalamo-subthalamic paramedian infarct: An interesting case report

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    Subasree Ramakrishnan

    2013-01-01

    Full Text Available A 42-year-old young lady presented with acute onset of dizziness, drooping of left eye with binocular diplopia and inability to walk unassisted. She had past history of uncontrolled diabetes mellitus and hypertension. On examination, she had left fascicular type of third nerve palsy, vertical one and half syndrome (VOHS, left internuclear ophthalmoplegia and skew deviation with ipsilesional hypertropia. She also had thalamic astasia and right unilateral asterixis. Her MRI revealed T2 and Flair hyper intense signal changes with restricted diffusion in the left thalamus, subthalamus and left midbrain. MR Angiography was normal. Thalamic-subthalamic paramedian territory infarct is relatively uncommon. It can present with oculomotor abnormalities including vertical one and half syndrome, skew deviation, thalamic astasia and asterixis. This case is reported for the rarity of the presenting clinical findings in unilateral thalamo-mesencephalic infarcts.

  6. Steroid-responsive thalamic lesions accompanying microbleeds in a case of Hashimoto's encephalopathy with autoantibodies against α-enolase.

    Science.gov (United States)

    Yamaguchi, Yoshitaka; Wada, Manabu; Tanji, Haruko; Kurokawa, Katsuro; Kawanami, Toru; Tanji, Kazuyo; Yoneda, Makoto; Kato, Takeo

    2013-01-01

    A 67-year-old man receiving antithrombotic therapy developed rapidly progressive amnesia. T2-weighted images of brain MRI revealed hyperintense lesions in the bilateral thalami accompanied by microbleeds. Antithyroglobulin antibodies and autoantibodies against the N-terminal of α-enolase (NAE) were identified in the patient's serum; therefore, Hashimoto's encephalopathy (HE) was suspected. Although the patient's radiological findings improved following steroid therapy, his symptoms did not improve, possibly due to increased thalamic microbleeds. Because anti-NAE antibodies are possibly associated with vasculitis, HE accompanied by anti-NAE antibodies may be exacerbated by microbleeds in patients receiving antithrombotic therapy.

  7. Tc-99m ECD brain SPECT in patients with traumatic brain injury: evaluating distribution of hypoperfusion and assessment of cognitive and behavioral impairment in relation to thalamic hypoperfusion

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    Park, Soon Ah; Lim, Seok Tae; Sohn, Myung Hee [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2000-12-01

    We evaluated the distribution of hypoperfusion in patients with traumatic brain injury (TBI) and the relationship of thalamic hypoperfusion to severity of cognitive and behavioral sequelae. Tc-99m ECD SPECT and MRI were performed in 103 patients (M/F=81/22, mean age 34.7{+-} 15.4 yrs) from 0.5 to 55 months (mean 10.3 months) after TBI. The patients were divided into three groups showing no abnormalities (G1), focal (G2) and diffuse injury (G3) on MRI. Psychometric tests assessed 11 cognitive or behavioral items. In all patients, we evaluated the distribution of hypoperfused areas in SPECT, and in 57/103 patients, neuropsychological (NP) abnormalities in patients with thalamic hypoperfusion were compared with those of patients without thalamic hypoperfusion. The perfusion dificits were most frequently located in the frontal lobe (G1, 42.3%: G2 34.5%: G3 33.3%), temporal lobe (24{approx}26%) thalami (21{approx}22.4%), parietal and occipital lobe ({<=}10%). Numbers of NP abnormalities in the cases of cortical hypoperfusion with or without concomitant thalamic hypoperfusion were following: the former 4.7{+-}1.5 and the latter 3.2{+-}1.4 in G1, 5.0{+-}1.1 and 4.8{+-}1.2 in G2, 6.8{+-}1.8 and 6.3{+-}1.1 in G3, respectively. This difference according to thalamic hypoperfusion was significant in G1 (p=0.002), but was not significant in G2 or G3. SPECT in patients with TBI had demonstrated hypoperfusion mostly involving the frontal, temporal and thalami. In normal group on MRI, frontal hypoperfusion was more prominent than that of any other group, Furthermore in this group, SPECT could predict severity of NP outcome by concomitant thalamic hypoperfusion with cerebral cortical abnormalities.

  8. Impaired visual short-term memory capacity is distinctively associated with structural connectivity of the posterior thalamic radiation and the splenium of the corpus callosum in preterm-born adults.

    Science.gov (United States)

    Menegaux, Aurore; Meng, Chun; Neitzel, Julia; Bäuml, Josef G; Müller, Hermann J; Bartmann, Peter; Wolke, Dieter; Wohlschläger, Afra M; Finke, Kathrin; Sorg, Christian

    2017-04-15

    Preterm birth is associated with an increased risk for lasting changes in both the cortico-thalamic system and attention; however, the link between cortico-thalamic and attention changes is as yet little understood. In preterm newborns, cortico-cortical and cortico-thalamic structural connectivity are distinctively altered, with increased local clustering for cortico-cortical and decreased integrity for cortico-thalamic connectivity. In preterm-born adults, among the various attention functions, visual short-term memory (vSTM) capacity is selectively impaired. We hypothesized distinct associations between vSTM capacity and the structural integrity of cortico-thalamic and cortico-cortical connections, respectively, in preterm-born adults. A whole-report paradigm of briefly presented letter arrays based on the computationally formalized Theory of Visual Attention (TVA) was used to quantify parameter vSTM capacity in 26 preterm- and 21 full-term-born adults. Fractional anisotropy (FA) of posterior thalamic radiations and the splenium of the corpus callosum obtained by diffusion tensor imaging were analyzed by tract-based spatial statistics and used as proxies for cortico-thalamic and cortico-cortical structural connectivity. The relationship between vSTM capacity and cortico-thalamic and cortico-cortical connectivity, respectively, was significantly modified by prematurity. In full-term-born adults, the higher FA in the right posterior thalamic radiation the higher vSTM capacity; in preterm-born adults this FA-vSTM-relationship was inversed. In the splenium, higher FA was correlated with higher vSTM capacity in preterm-born adults, whereas no significant relationship was evident in full-term-born adults. These results indicate distinct associations between cortico-thalamic and cortico-cortical integrity and vSTM capacity in preterm-and full-term-born adults. Data suggest compensatory cortico-cortical fiber re-organization for attention deficits after preterm delivery

  9. Increases in the right dorsolateral prefrontal cortex and decreases the rostral prefrontal cortex activation after-8 weeks of focused attention based mindfulness meditation.

    Science.gov (United States)

    Tomasino, Barbara; Fabbro, Franco

    2016-02-01

    Mindfulness meditation is a form of attention control training. The training exercises the ability to repeatedly focus attention. We addressed the activation changes related to an 8-weeks mindfulness-oriented focused attention meditation training on an initially naïve subject cohort. Before and after training participants underwent an fMRI experiment, thus, although not strictly a cross over design, they served as their internal own control. During fMRI they exercised focused attention on breathing and body scan as compared to resting. We found increased and decreased activation in different parts of the prefrontal cortex (PFC) by comparing pre- vs. post-mindfulness training (MT) during breathing and body scan meditation exercises that were compared against their own resting state. In the post-MT (vs. pre-MT) meditation increased activation in the right dorsolateral PFC and in the left caudate/anterior insula and decreased activation in the rostral PFC and right parietal area 3b. Thus a brief mindfulness training caused increased activation in areas involved in sustaining and monitoring the focus of attention (dorsolateral PFC), consistent with the aim of mindfulness that is exercising focused attention mechanisms, and in the left caudate/anterior insula involved in attention and corporeal awareness and decreased activation in areas part of the "default mode" network and is involved in mentalizing (rostral PFC), consistent with the ability trained by mindfulness of reducing spontaneous mind wandering.

  10. Specification of embryonic stem cell-derived tissues into eye fields by Wnt signaling using rostral diencephalic tissue-inducing culture.

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    Sakakura, Eriko; Eiraku, Mototsugu; Takata, Nozomu

    2016-08-01

    The eyes are subdivided from the rostral diencephalon in early development. How the neuroectoderm regulates this subdivision, however, is largely unknown. Taking advantage of embryonic stem cell (ESC) culture using a Rax reporter line to monitor rostral diencephalon formation, we found that ESC-derived tissues at day 7 grown in Glasgow Minimum Expression Media (GMEM) containing knockout serum replacement (KSR) exhibited higher levels of expression of axin2, a Wnt target gene, than those grown in chemically defined medium (CDM). Surprisingly, Wnt agonist facilitated eye field-like tissue specification in CDM. In contrast, the addition of Wnt antagonist diminished eye field tissue formation in GMEM+KSR. Furthermore, the morphological formation of the eye tissue anlage, including the optic vesicle, was accompanied by Wnt signaling activation. Additionally, using CDM culture, we developed an efficient method for generating Rax+/Chx10+ retinal progenitors, which could become fully stratified retina. Here we provide a new avenue for exploring the mechanisms of eye field specification in vitro.

  11. The rostral prefrontal cortex underlies individual differences in working memory capacity: An approach from the hierarchical model of the cognitive control.

    Science.gov (United States)

    Minamoto, Takehiro; Yaoi, Ken; Osaka, Mariko; Osaka, Naoyuki

    2015-10-01

    Neuroimaging and behavioral evidence has suggested that the lateral prefrontal cortex is involved in individual differences in working memory capacity (WMC). However, few studies have localized the neural structures that differentiate high and low WMC individuals, considering the functional architecture of the prefrontal cortex. The present study aimed to identify a frontal region that underlies individual differences from the perspective of the hierarchical architecture of the frontal cortex. By manipulating an episodic factor of cognitive control (control in selecting an appropriate task set according to a temporal context) and using a parametric modulation analysis, we found that both high- and low- WMC individuals have similar activation patterns in the premotor cortex (BA6, 8), caudal prefrontal cortex (BA44, 45), and frontopolar cortex (BA10, 11), but differed in the rostral part of the prefrontal cortex (BA46/47); high WMC individuals showed greater activation in the higher episodic control condition, whereas low WMC individuals showed reduced activation when episodic control was required. Similar patterns of activation were found in the right inferior parietal and middle/inferior temporal cortices. These results indicate that the rostral prefrontal cortex, which supports episodic cognitive control, possibly by sending a weighting signal toward the inferior parietal and middle/inferior temporal cortices that modulate saliency and sensory processing, underlies individual differences in WMC. Episodic control account, which considers the organization of the prefrontal cortex, fits well with previous findings of individual differences in WMC.

  12. Noradrenergic transmission in the central medial thalamic nucleus modulates the electroencephalographic activity and emergence from propofol anesthesia in rats.

    Science.gov (United States)

    Fu, Bao; Yu, Tian; Yuan, Jie; Gong, Xingrui; Zhang, Mazhong

    2017-03-01

    At present, the mechanisms by which general anesthetics causing loss of consciousness remain unclear. The central medial thalamic nucleus (CMT) is a rarely studied component of the midline thalamic complex, which is deemed to be a part of the nonspecific arousal system. Although the CMT participates in modulating arousal and receives excitatory noradrenergic projections from locus coeruleus, it remains unknown whether the noradrenergic pathway in the CMT takes part in modulating the arousal system. Therefore, we hypothesized that noradrenergic transmission in the CMT is involved in modulating induction and emergence of propofol anesthesia. First, we infused norepinephrine (NE) into the CMT to observe the role of CMT noradrenergic pathway in modulating the anesthetic state induced by propofol. The results showed that microinjection of NE into the CMT accelerated emergence from propofol anesthesia, but had no impact on the induction of or sensitivity to propofol anesthesia in rats. In addition, infusion of NE into the CMT caused electroencephalography changes in the prefrontal cortex and the anterior cingulate cortex. Finally, we used a whole-cell patch clamp to examine the effects of NE on neuronal excitability and GABAergic transmission in the CMT. In the CMT slices, propofol suppressed neuronal excitability and enhanced GABAergic transmission, while application of NE partly reversed these effects. These findings support the hypothesis that the CMT noradrenergic pathway plays an important role in modulating the emergence from general anesthesia. © 2017 International Society for Neurochemistry.

  13. Discontinuous Galerkin finite element method for solving population density functions of cortical pyramidal and thalamic neuronal populations.

    Science.gov (United States)

    Huang, Chih-Hsu; Lin, Chou-Ching K; Ju, Ming-Shaung

    2015-02-01

    Compared with the Monte Carlo method, the population density method is efficient for modeling collective dynamics of neuronal populations in human brain. In this method, a population density function describes the probabilistic distribution of states of all neurons in the population and it is governed by a hyperbolic partial differential equation. In the past, the problem was mainly solved by using the finite difference method. In a previous study, a continuous Galerkin finite element method was found better than the finite difference method for solving the hyperbolic partial differential equation; however, the population density function often has discontinuity and both methods suffer from a numerical stability problem. The goal of this study is to improve the numerical stability of the solution using discontinuous Galerkin finite element method. To test the performance of the new approach, interaction of a population of cortical pyramidal neurons and a population of thalamic neurons was simulated. The numerical results showed good agreement between results of discontinuous Galerkin finite element and Monte Carlo methods. The convergence and accuracy of the solutions are excellent. The numerical stability problem could be resolved using the discontinuous Galerkin finite element method which has total-variation-diminishing property. The efficient approach will be employed to simulate the electroencephalogram or dynamics of thalamocortical network which involves three populations, namely, thalamic reticular neurons, thalamocortical neurons and cortical pyramidal neurons.

  14. Resting-State Cortico-Thalamic-Striatal Connectivity Predicts Response to Dorsomedial Prefrontal rTMS in Major Depressive Disorder

    Science.gov (United States)

    Salomons, Tim V; Dunlop, Katharine; Kennedy, Sidney H; Flint, Alastair; Geraci, Joseph; Giacobbe, Peter; Downar, Jonathan

    2014-01-01

    Despite its high toll on society, there has been little recent improvement in treatment efficacy for major depressive disorder (MDD). The identification of biological markers of successful treatment response may allow for more personalized and effective treatment. Here we investigate whether resting-state functional connectivity predicted response to treatment with repetitive transcranial magnetic stimulation (rTMS) to dorsomedial prefrontal cortex (dmPFC). Twenty-five individuals with treatment-refractory MDD underwent a 4-week course of dmPFC-rTMS. Before and after treatment, subjects received resting-state functional MRI scans and assessments of depressive symptoms using the Hamilton Depresssion Rating Scale (HAMD17). We found that higher baseline cortico-cortical connectivity (dmPFC-subgenual cingulate and subgenual cingulate to dorsolateral PFC) and lower cortico-thalamic, cortico-striatal, and cortico-limbic connectivity were associated with better treatment outcomes. We also investigated how changes in connectivity over the course of treatment related to improvements in HAMD17 scores. We found that successful treatment was associated with increased dmPFC-thalamic connectivity and decreased subgenual cingulate cortex-caudate connectivity, Our findings provide insight into which individuals might respond to rTMS treatment and the mechanisms through which these treatments work. PMID:24150516

  15. Engineering a thalamo-cortico-thalamic circuit on SpiNNaker: a preliminary study towards modelling sleep and wakefulness

    Directory of Open Access Journals (Sweden)

    Basabdatta Sen Bhattacharya

    2014-05-01

    Full Text Available We present a preliminary study of a thalamo-cortico-thalamic (TCT implementation on SpiNNaker (Spiking Neural Network architecture, a brain inspired hardware platform designed to incorporate the inherent biological properties of parallelism, fault tolerance and energy efficiency. These attributes make SpiNNaker an ideal platform for simulating biologically plausible computational models. Our focus in this work is to design a TCT framework that can be simulated on SpiNNaker to mimic dynamical behaviour similar to Electroencephalogram (EEG time and power-spectra signatures in sleep-wake transition. The scale of the model is minimised for simplicity in this proof-of-concept study; thus the total number of spiking neurons is approximately 1000 and represents a `mini-column' of the thalamocortical tissue. All data on model structure, synaptic layout and parameters is inspired from previous studies and abstracted at a level that is appropriate to the aims of the current study as well as computationally suitable for model simulation on a small 4-chip SpiNNaker system. The initial results from selective deletion of synaptic connectivity parameters in the model show similarity with EEG time series characteristics of sleep and wakefulness. These observations provide a positive perspective and a basis for future implementation of a very large scale biologically plausible model of thalamo-cortico-thalamic interactivity---the essential brain circuit that regulates the biological sleep-wake cycle and associated EEG rhythms.

  16. The contribution of the lateral posterior and anteroventral thalamic nuclei on spontaneous recurrent seizures in the pilocarpine model of epilepsy

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    Scorza Fulvio Alexandre

    2002-01-01

    Full Text Available The pilocarpine model of epilepsy in rats is characterised by the occurrence of spontaneous seizures (SRSs during the chronic period that recur 2-3 times per week during the whole animal life. In a previous study on brain metabolism during the chronic period of the pilocarpine model it was possible to observe that, among several brain structures, the lateral posterior thalamic nuclei (LP showed a strikingly increased metabolism. Some evidences suggest that the LP can participate in an inhibitory control system involved in the propagation of the seizures. The aim of the present study was to verify the role of LP in the expression and frequency of spontaneous seizures observed in the pilocarpine model. Ten adult male rats presenting SRSs were monitored for behavioural events by video system one month before and one month after LP ibotenic acid lesion. Another group of chronic epileptic rats (n=10 had the anteroventral thalamic nuclei (AV lesioned by ibotenic acid. After the surgical procedure, the animals were sacrified and the brains were processed for histological analysis by the Nissl method. The LP group seizure frequency was 3.1±1.9 before ibotenic acid injection and showed an increase (16.3±7.2 per week after LP lesion. No changes in SRSs frequency were observed in the AV group after ibotenic lesion in these nuclei. These results seem to suggest that LP play a role in the seizure circuitry inhibiting the expression of spontaneous seizures in the pilocarpine model.

  17. The facilitatory influence of anterior cingulate cortex on ON-OFF response of tactile neuron in thalamic ventrobasal nucleus

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The structures of limbic system have been found to modulate the auditory, visual and pain afferent signals in the related nuclei of thalamus. One of those structures is anterior cingulate cortex (ACC) that influences nocuous response of the pain-sensitive neurons in the ventropostero-lateral nucleus of thalamus. Thus, we inferred that ACC would also modulate tactile information at the thalamic level. To test this assumption, single units were recorded extracellularly from thalamic ventrobasal nucleus (VB). Tactile ON-OFF response and the relationship between different patterns of the responses and the parameters of tactile stimulation were examined. Furthermore, the influence of ACC on the tactile ON-OFF response was studied. ACC stimulation was found to produce a facilitatory effect on the OFF-response of ON-OFF neurons. It lowered the threshold of the off-response of that neuron, and therefore changed the response pattern or enhanced the firing rate of the OFF-response of the neuron. The study on receptive fields of ON-OFF neurons showed that the excitation of the ACC could change an ON-response on the verge of a receptive field into an ON-OFF response. The above results suggest that the ACC modulation sharpens the response of a VB neuron to a moving stimulus within its receptive field, indicating that the limbic system can modulate tactile ascending sensory information.

  18. The facilitatory influence of anterior cingulate cortex on ON-OFF response of tactile neuron in thalamic ventrobasal nucleus

    Institute of Scientific and Technical Information of China (English)

    曹晓华; 卢湘岳; 周绍慈

    2000-01-01

    The structures of limbic system have been found to modulate the auditory, visual and pain afferent signals in the related nuclei of thalamus. One of those structures is anterior cingulate cortex (ACC) that influences nocuous response of the pain-sensitive neurons in the ventropos-tero-lateral nucleus of thalamus. Thus, we inferred that ACC would also modulate tactile information at the thalamic level. To test this assumption, single units were recorded extracellularly from thalamic ventrobasal nucleus (VB). Tactile ON-OFF response and the relationship between different patterns of the responses and the parameters of tactile stimulation were examined. Furthermore, the influence of ACC on the tactile ON-OFF response was studied. ACC stimulation was found to produce a facilitatory effect on the OFF-response of ON-OFF neurons. It lowered the threshold of the off-response of that neuron, and therefore changed the response pattern or enhanced the firing rate of the OFF-response of the neuron. The study on rec

  19. In vivo optogenetic control of striatal and thalamic neurons in non-human primates.

    Directory of Open Access Journals (Sweden)

    Adriana Galvan

    Full Text Available Electrical and pharmacological stimulation methods are commonly used to study neuronal brain circuits in vivo, but are problematic, because electrical stimulation has limited specificity, while pharmacological activation has low temporal resolution. A recently developed alternative to these methods is the use of optogenetic techniques, based on the expression of light sensitive channel proteins in neurons. While optogenetics have been applied in in vitro preparations and in in vivo studies in rodents, their use to study brain function in nonhuman primates has been limited to the cerebral cortex. Here, we characterize the effects of channelrhodopsin-2 (ChR2 transfection in subcortical areas, i.e., the putamen, the external globus pallidus (GPe and the ventrolateral thalamus (VL of rhesus monkeys. Lentiviral vectors containing the ChR2 sequence under control of the elongation factor 1α promoter (pLenti-EF1α -hChR2(H134R-eYFP-WPRE, titer 10⁹ particles/ml were deposited in GPe, putamen and VL. Four weeks later, a probe combining a conventional electrode and an optic fiber was introduced in the previously injected brain areas. We found light-evoked responses in 31.5% and 32.7% of all recorded neurons in the striatum and thalamus, respectively, but only in 2.5% of recorded GPe neurons. As expected, most responses were time-locked increases in firing, but decreases or mixed responses were also seen, presumably via ChR2-mediated activation of local inhibitory connections. Light and electron microscopic analyses revealed robust expression of ChR2 on the plasma membrane of cell somas, dendrites, spines and terminals in the striatum and VL. This study demonstrates that optogenetic experiments targeting the striatum and basal ganglia-related thalamic nuclei can be successfully achieved in monkeys. Our results indicate important differences of the type and magnitude of responses in each structure. Experimental conditions such as the vector used, the

  20. Thalamic Deep Brain Stimulation for Neuropathic Pain: Efficacy at Three Years' Follow-Up.

    Science.gov (United States)

    Abreu, Vasco; Vaz, Rui; Rebelo, Virgínia; Rosas, Maria José; Chamadoira, Clara; Gillies, Martin J; Aziz, Tipu Z; Pereira, Erlick A C

    2017-07-01

    Chronic neuropathic pain is estimated to affect 3-4.5% of the worldwide population, posing a serious burden to society. Deep Brain Stimulation (DBS) is already established for movement disorders and also used to treat some "off-label" conditions. However, DBS for the treatment of chronic, drug refractory, neuropathic pain, has shown variable outcomes with few studies performed in the last decade. Thus, this procedure has consensus approval in parts of Europe but not the USA. This study prospectively evaluated the efficacy at three years of DBS for neuropathic pain. Sixteen consecutive patients received 36 months post-surgical follow-up in a single-center. Six had phantom limb pain after amputation and ten deafferentation pain after brachial plexus injury, all due to traumas. To evaluate the efficacy of DBS, patient-reported outcome measures were collated before and after surgery, using a visual analog scale (VAS) score, University of Washington Neuropathic Pain Score (UWNPS), Brief Pain Inventory (BPI), and 36-Item Short-Form Health Survey (SF-36). Contralateral, ventroposterolateral sensory thalamic DBS was performed in sixteen patients with chronic neuropathic pain over 29 months. A postoperative trial of externalized DBS failed in one patient with brachial plexus injury. Fifteen patients proceeded to implantation but one patient with phantom limb pain after amputation was lost for follow-up after 12 months. No surgical complications or stimulation side effects were noted. After 36 months, mean pain relief was sustained, and the median (and interquartile range) of the improvement of VAS score was 52.8% (45.4%) (p = 0.00021), UWNPS was 30.7% (49.2%) (p = 0.0590), BPI was 55.0% (32.0%) (p = 0.00737), and SF-36 was 16.3% (30.3%) (p = 0.4754). DBS demonstrated efficacy at three years for chronic neuropathic pain after traumatic amputation and brachial plexus injury, with benefits sustained across all pain outcomes measures and slightly greater

  1. The pacemaker role of thalamic reticular nucleus in controlling spike-wave discharges and spindles

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    Fan, Denggui; Liao, Fucheng; Wang, Qingyun

    2017-07-01

    Absence epilepsy, characterized by 2-4 Hz spike-wave discharges (SWDs), can be caused by pathological interactions within the thalamocortical system. Cortical spindling oscillations are also demonstrated to involve the oscillatory thalamocortical rhythms generated by the synaptic circuitry of the thalamus and cortex. This implies that SWDs and spindling oscillations can share the common thalamocortical mechanism. Additionally, the thalamic reticular nucleus (RE) is hypothesized to regulate the onsets and propagations of both the epileptic SWDs and sleep spindles. Based on the proposed single-compartment thalamocortical neural field model, we firstly investigate the stimulation effect of RE on the initiations, terminations, and transitions of SWDs. It is shown that the activations and deactivations of RE triggered by single-pulse stimuli can drive the cortical subsystem to behave as the experimentally observed onsets and self-abatements of SWDs, as well as the transitions from 2-spike and wave discharges (2-SWDs) to SWDs. In particular, with increasing inhibition from RE to the specific relay nucleus (TC), rich transition behaviors in cortex can be obtained through the upstream projection path, RE → TC → Cortex . Although some of the complex dynamical patterns can be expected from the earlier single compartment thalamocortical model, the effect of brain network topology on the emergence of SWDs and spindles, as well as the transitions between them, has not been fully investigated. We thereby develop a spatially extended 3-compartment coupled network model with open-/closed-end connective configurations, to investigate the spatiotemporal effect of RE on the SWDs and spindles. Results show that the degrees of activations of RE 1 can induce the rich spatiotemporal evolution properties including the propagations from SWDs to spindles within different compartments and the transitions between them, through the RE 1 → TC 1 → Cortex 1 and Cortex 1 → Cortex 2

  2. Social cognitive and neurocognitive deficits in inpatients with unilateral thalamic lesions — pilot study

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    Wilkos E

    2015-04-01

    Full Text Available Ewelina Wilkos,2 Timothy JB Brown,3 Ksenia Slawinska,1 Katarzyna A Kucharska2,3 1Department of Neurology, 2Department of Neuroses, Personality and Eating Disorders Institute of Psychiatry and Neurology, Warsaw, Poland; 3Department of Medical Education, Hull York Medical School, Hull, UK Background: The essential role of the thalamus in neurocognitive processes has been well documented. In contrast, relatively little is known about its involvement in social cognitive processes such as recognition of emotion, mentalizing, or empathy. The aim of the study: This study was designed to compare the performance of eight patients (five males, three females, mean age ± SD: 63.7±7.9 years at early stage of unilateral thalamic lesions and eleven healthy controls (six males, five females, 49.6±12.2 years in neurocognitive tests (CogState Battery: Groton Maze Learning Test, GML; Groton Maze Learning Test-Delayed Recall, GML-DR; Detection Task, DT; Identification Task, IT; One Card Learning Task, OCLT; One Back Task, OBT; Two Back Task, TBT; Set-Shifting Task, S-ST and other well-known tests (Benton Visual Retention Test, BVRT; California Verbal Learning Test, CVLT; The Rey-Osterrieth Complex Figure Test, ROCF; Trail Making Test, TMT part A and B; Color – Word Stroop Task, CWST; Verbal Fluency Test, VFT, and social cognitive tasks (The Penn Emotion Recognition Test, ER40; Penn Emotion Discrimination Task, EmoDiff40; The Penn Emotional Acuity Test, PEAT40; Reading the Mind in the Eyes Test, revised version II; Toronto Alexithymia Scale, TAS-20. Methods: Thalamic-damaged subjects were included if they experienced a single-episode ischemic stroke localized in right or left thalamus. The patients were examined at 3 weeks after the stroke onset. All were right handed. In addition, the following clinical scales were used: the Mini-Mental State Examination (MMSE, Spielberger State-Trait Anxiety Inventory (STAI, Beck Depression Inventory (BDI II. An inclusion

  3. Thalamic alterations in preterm neonates and their relation to ventral striatum disturbances revealed by a combined shape and pose analysis.

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    Lao, Yi; Wang, Yalin; Shi, Jie; Ceschin, Rafael; Nelson, Marvin D; Panigrahy, Ashok; Leporé, Natasha

    2016-01-01

    Finding the neuroanatomical correlates of prematurity is vital to understanding which structures are affected, and to designing efficient prevention and treatment strategies. Converging results reveal that thalamic abnormalities are important indicators of prematurity. However, little is known about the localization of the abnormalities within the subnuclei of the thalamus, or on the association of altered thalamic development with other deep gray matter disturbances. Here, we aim to investigate the effect of prematurity on the thalamus and the putamen in the neonatal brain, and further investigate the associated abnormalities between these two structures. Using brain structural magnetic resonance imaging, we perform a novel combined shape and pose analysis of the thalamus and putamen between 17 preterm (41.12 ± 5.08 weeks) and 19 term-born (45.51 ± 5.40 weeks) neonates at term equivalent age. We also perform a set of correlation analyses between the thalamus and the putamen, based on the surface and pose results. We locate significant alterations on specific surface regions such as the anterior and ventral anterior (VA) thalamic nuclei, and significant relative pose changes of the left thalamus and the right putamen. In addition, we detect significant association between the thalamus and the putamen for both surface and pose parameters. The regions that are significantly associated include the VA, and the anterior and inferior putamen. We detect statistically significant surface deformations and pose changes on the thalamus and putamen, and for the first time, demonstrate the feasibility of using relative pose parameters as indicators for prematurity in neonates. Our methods show that regional abnormalities of the thalamus are associated with alterations of the putamen, possibly due to disturbed development of shared pre-frontal connectivity. More specifically, the significantly correlated regions in these two structures point to frontal

  4. Influence of a serotonin receptor antagonist, 5-HTP-DP-hex, on spinal and thalamic nociceptive neurons in rats.

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    Emmers, R; Tamir, H; Wilchek, M

    1987-06-01

    The antinociceptive properties of a new synthetic dipeptide (N-hexanoyl-5-hydroxytryptophyl-5-hydroxytryptophan amide, or 5-HTP-DP-hex) were studied in rats by an electrophysiological method. After an i.p. injection of alpha-chloralose and urethane, the animals were prepared for stereotaxic approach to the nucleus ventralis posterolateralis of the thalamus. With tungsten microelectrodes, individual nociceptive neurons in the nucleus were identified by the sequence of spikes emitted in response to single-pulse stimulation of the sciatic nerve. In addition to the usual short-latency spikes, a nociceptive neuron fired late spikes at regular intervals within 500 ms following each stimulus. When the spikes were accumulated in poststimulus time histograms, the short-latency spikes compiled an intensity-related (I) peak. The late spikes formed modality-related (M) peaks with spacing characteristic of nociception. Intracarotid infusion of 5-HTP-DP-hex (1 mg/kg) elevated the delayed portion of the I peak and the first M peak. This effect was followed in 25 min by suppression of all M peaks. The control record could be reinstated at any time by 5-hydroxytryptophan (3.5 mg/kg), or by natural recovery in 2.5 h. Responses evoked from a thalamic nociceptive neuron by single-pulse stimulation of the spinothalamic tract were modified by 5-HTP-DP-hex in a similar manner, except that no elevation of the activity peaks was observed. As shown previously, elevation of the delayed I peak and M1 indicated an increased input of A-delta and C fibers, respectively. The increased input lowers the response threshold and may represent hyperalgesia. Suppression of the M peaks may result from altered function of the positive feedback loop in the nociceptive system at the thalamic level, and may represent analgesia. Naloxone, methysergide, as well as ketanserin had no significant effect on the response histograms. These findings suggested that 5-HTP-DP-hex, a known serotonin receptor antagonist

  5. The human thalamic somatic sensory nucleus [ventral caudal (Vc)] shows neuronal mechanoreceptor-like responses to optimal stimuli for peripheral mechanoreceptors.

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    Weiss, N; Ohara, S; Johnson, K O; Lenz, F A

    2009-02-01

    Although the response of human cutaneous mechanoreceptors to controlled stimuli is well studied, it is not clear how these peripheral signals may be reflected in neuronal activity of the human CNS. We now test the hypothesis that individual neurons in the human thalamic principal somatic sensory nucleus [ventral caudal (Vc)] respond selectively to the optimal stimulus for one of the four mechanoreceptors. The optimal stimuli for particular mechanoreceptors were defined as follows: Pacinian corpuscles (PC), vibration at 128 Hz; rapidly adapting (RA), vibration at 32 or 64 Hz; slowly adapting type 1 (SA1), edge; slowly adapting type 2 (SA2), skin stretch. Nineteen neurons had a significant response to at least one optimal stimulus, and 17 had a significantly greater response to one stimulus than to the other three, including 7 PC-related, 7 RA-like, 3 SA1-like, and 2 SA2-like neurons. One of each of the SA1- and SA2-like thalamic neurons responded to vibration with firing rates that were lower than those to edge or stretch but not significantly. Except in the case of PC-related neurons, the receptive field (RF) sizes were larger for these thalamic neurons than for the corresponding mechanoreceptor. Von Frey thresholds were higher than those for the corresponding human RA and SA1 mechanoreceptors. These results suggest that there is a convergence of pathways transmitting input from multiple mechanoreceptors of one type on single thalamic neurons via the dorsal columns. They are also consistent with the presence of primate thalamic elements of modality and somatotopic isorepresentation.

  6. The rostral migratory stream generates hippocampal CA1 pyramidal-like neurons in a novel organotypic slice co-culture model

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    Ilyas Singec

    2015-10-01

    Full Text Available The mouse subventricular zone (SVZ generates large numbers of neuroblasts, which migrate in a distinct pathway, the rostral migratory stream (RMS, and replace specific interneurons in the olfactory bulb (OB. Here, we introduce an organotypic slice culture model that directly connects the RMS to the hippocampus as a new destination. RMS neuroblasts widely populate the hippocampus and undergo cellular differentiation. We demonstrate that RMS cells give rise to various neuronal subtypes and, surprisingly, to CA1 pyramidal neurons. Pyramidal neurons are typically generated before birth and are lost in various neurological disorders. Hence, this unique slice culture model enables us to investigate their postnatal genesis under defined in vitro conditions from the RMS, an unanticipated source for hippocampal pyramidal neurons.

  7. On the genesis of spike-wave oscillations in a mean-field model of human thalamic and corticothalamic dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Serafim [Department of Mathematical Sciences, Loughborough University, Leicestershire, LE11 3TU (United Kingdom); Terry, John R. [Department of Mathematical Sciences, Loughborough University, Leicestershire, LE11 3TU (United Kingdom)]. E-mail: j.r.terry@lboro.ac.uk; Breakspear, Michael [Black Dog Institute, Randwick, NSW 2031 (Australia); School of Psychiatry, UNSW, NSW 2030 (Australia)

    2006-07-10

    In this Letter, the genesis of spike-wave activity-a hallmark of many generalized epileptic seizures-is investigated in a reduced mean-field model of human neural activity. Drawing upon brain modelling and dynamical systems theory, we demonstrate that the thalamic circuitry of the system is crucial for the generation of these abnormal rhythms, observing that the combination of inhibition from reticular nuclei and excitation from the cortical signal, interplay to generate the spike-wave oscillation. The mechanism revealed provides an explanation of why approaches based on linear stability and Heaviside approximations to the activation function have failed to explain the phenomena of spike-wave behaviour in mean-field models. A mathematical understanding of this transition is a crucial step towards relating spiking network models and mean-field approaches to human brain modelling.

  8. Increased noradrenaline levels in the rostral pons can be reversed by M1 antagonist in a rat model of post-traumatic stress disorder.

    Science.gov (United States)

    Terzioğlu, Berna; Kaleli, Melisa; Aydın, Banu; Ketenci, Sema; Cabadak, Hülya; Gören, M Zafer

    2013-08-01

    The dysregulation of hypothalamic-pituitary-adrenal axis and noradrenergic, serotonergic and glutamatergic systems are thought to be involved in the pathophysiology of post-traumatic stress disorder. The effect of selective M1 muscarinic receptor antagonist, pirenzepine on anxiety indices was investigated by using elevated plus maze, following exposure to trauma reminder. Upon receiving the approval of ethics committee, Sprague-Dawley rats were exposed to dirty cat litter (trauma) for 10 min and 1 week later, the rats confronted to a trauma reminder (clean litter). The rats also received intraperitoneal pirenzepine (1 or 2 mg/kg/day) or saline for 8 days. Noradrenaline (NA) concentration in the rostral pons was analyzed by HPLC with electrochemical detection. The anxiety indices of the rats subjected to the trauma reminder were increased when compared to control rats (p Pirenzepine treatment in traumatized rats displayed similar anxiety indices of non-traumatized rats treated with physiological saline. Although freezing time was prolonged with pirenzepine in traumatized groups the change was not found statistically significant. The NA level was 1.5 ± 0.1 pg/mg in non-traumatized rats and increased to 2.4 ± 0.2 pg/mg in traumatized rats. Bonferroni post hoc test revealed that the NA content of the rostral pons of the traumatized rats treated with physiological saline was significantly higher than the content of other groups (p pirenzepine indicating the roles of M1 receptors.

  9. Vesicular glutamate transporter 2 is required for the respiratory and parasympathetic activation produced by optogenetic stimulation of catecholaminergic neurons in the rostral ventrolateral medulla of mice in vivo.

    Science.gov (United States)

    Abbott, Stephen B G; Holloway, Benjamin B; Viar, Kenneth E; Guyenet, Patrice G

    2014-01-01

    Catecholaminergic neurons of the rostral ventrolateral medulla (RVLM-CA neurons; C1 neurons) contribute to the sympathetic, parasympathetic and neuroendocrine responses elicited by physical stressors such as hypotension, hypoxia, hypoglycemia, and infection. Most RVLM-CA neurons express vesicular glutamate transporter (VGLUT)2, and may use glutamate as a ionotropic transmitter, but the importance of this mode of transmission in vivo is uncertain. To address this question, we genetically deleted VGLUT2 from dopamine-β-hydroxylase-expressing neurons in mice [DβH(Cre/0) ;VGLUT2(flox/flox) mice (cKO mice)]. We compared the in vivo effects of selectively stimulating RVLM-CA neurons in cKO vs. control mice (DβH(Cre/0) ), using channelrhodopsin-2 (ChR2-mCherry) optogenetics. ChR2-mCherry was expressed by similar numbers of rostral ventrolateral medulla (RVLM) neurons in each strain (~400 neurons), with identical selectivity for catecholaminergic neurons (90-99% colocalisation with tyrosine hydroxylase). RVLM-CA neurons had similar morphology and axonal projections in DβH(Cre/0) and cKO mice. Under urethane anesthesia, photostimulation produced a similar pattern of activation of presumptive ChR2-positive RVLM-CA neurons in DβH(Cre/0) and cKO mice. Photostimulation in conscious mice produced frequency-dependent respiratory activation in DβH(Cre/0) mice but no effect in cKO mice. Similarly, photostimulation under urethane anesthesia strongly activated efferent vagal nerve activity in DβH(Cre/0) mice only. Vagal responses were unaffected by α1 -adrenoreceptor blockade. In conclusion, two responses evoked by RVLM-CA neuron stimulation in vivo require the expression of VGLUT2 by these neurons, suggesting that the acute autonomic responses driven by RVLM-CA neurons are mediated by glutamate.

  10. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function.

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    Carlos Castejon

    Full Text Available Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1 in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas.

  11. Control of Somatosensory Cortical Processing by Thalamic Posterior Medial Nucleus: A New Role of Thalamus in Cortical Function

    Science.gov (United States)

    Castejon, Carlos; Barros-Zulaica, Natali; Nuñez, Angel

    2016-01-01

    Current knowledge of thalamocortical interaction comes mainly from studying lemniscal thalamic systems. Less is known about paralemniscal thalamic nuclei function. In the vibrissae system, the posterior medial nucleus (POm) is the corresponding paralemniscal nucleus. POm neurons project to L1 and L5A of the primary somatosensory cortex (S1) in the rat brain. It is known that L1 modifies sensory-evoked responses through control of intracortical excitability suggesting that L1 exerts an influence on whisker responses. Therefore, thalamocortical pathways targeting L1 could modulate cortical firing. Here, using a combination of electrophysiology and pharmacology in vivo, we have sought to determine how POm influences cortical processing. In our experiments, single unit recordings performed in urethane-anesthetized rats showed that POm imposes precise control on the magnitude and duration of supra- and infragranular barrel cortex whisker responses. Our findings demonstrated that L1 inputs from POm imposed a time and intensity dependent regulation on cortical sensory processing. Moreover, we found that blocking L1 GABAergic inhibition or blocking P/Q-type Ca2+ channels in L1 prevents POm adjustment of whisker responses in the barrel cortex. Additionally, we found that POm was also controlling the sensory processing in S2 and this regulation was modulated by corticofugal activity from L5 in S1. Taken together, our data demonstrate the determinant role exerted by the POm in the adjustment of somatosensory cortical processing and in the regulation of cortical processing between S1 and S2. We propose that this adjustment could be a thalamocortical gain regulation mechanism also present in the processing of information between cortical areas. PMID:26820514

  12. Neuroprotective changes of thalamic degeneration-related gene expression by acupuncture in an MPTP mouse model of parkinsonism: microarray analysis.

    Science.gov (United States)

    Yeo, Sujung; Choi, Yeong-Gon; Hong, Yeon-Mi; Lim, Sabina

    2013-02-25

    Acupuncture stimulations at GB34 and LR3 inhibit the reduction of tyrosine hydroxylase in the nigrostriatal dopaminergic neurons in the parkinsonism animal models. Especially, behavioral tests showed that acupuncture stimulations improved the motor dysfunction in a previous study by almost 87.7%. The thalamus is a crucial area for the motor circuit and has been identified as one of the most markedly damaged areas in Parkinson's disease (PD), so acupuncture stimulations might also have an effect on the thalamic damage. In this study, gene expression changes following acupuncture at the acupoints were investigated in the thalamus of a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism model using a whole transcript array. It was confirmed that acupuncture at these acupoints could inhibit the decrease of tyrosine hydroxylase in the thalamic regions of the MPTP model, while acupuncture at the non-acupoints could not suppress this decrease by its level shown in the acupoints. GeneChip gene array analysis showed that 18 (5 annotated genes: Dnase1l2, Dusp4, Mafg, Ndph and Pgm5) of the probes down-regulated in MPTP, as compared to the control, were exclusively up-regulated by acupuncture at the acupoints, but not at the non-acupoints. In addition, 14 (3 annotated genes; Serinc2, Sp2 and Ucp2) of the probes up-regulated in MPTP, as compared to the control, were exclusively down-regulated by acupuncture at the acupoints, but not at the non-acupoints. The expression levels of the representative genes in the microarray were validated by real-time RT-PCR. These results suggest that the 32 probes (8 annotated genes) which are affected by MPTP and acupuncture may be responsible for exerting the inhibitory effect of acupuncture in the thalamus which can be damaged by MPTP intoxication.

  13. Differential spike timing and phase dynamics of reticular thalamic and prefrontal cortical neuronal populations during sleep spindles.

    Science.gov (United States)

    Gardner, Richard J; Hughes, Stuart W; Jones, Matthew W

    2013-11-20

    The 8-15 Hz thalamocortical oscillations known as sleep spindles are a universal feature of mammalian non-REM sleep, during which they are presumed to shape activity-dependent plasticity in neocortical networks. The cortex is hypothesized to contribute to initiation and termination of spindles, but the mechanisms by which it implements these roles are unknown. We used dual-site local field potential and multiple single-unit recordings in the thalamic reticular nucleus (TRN) and medial prefrontal cortex (mPFC) of freely behaving rats at rest to investigate thalamocortical network dynamics during natural sleep spindles. During each spindle epoch, oscillatory activity in mPFC and TRN increased in frequency from onset to offset, accompanied by a consistent phase precession of TRN spike times relative to the cortical oscillation. In mPFC, the firing probability of putative pyramidal cells was highest at spindle initiation and termination times. We thus identified "early" and "late" cell subpopulations and found that they had distinct properties: early cells generally fired in synchrony with TRN spikes, whereas late cells fired in antiphase to TRN activity and also had higher firing rates than early cells. The accelerating and highly structured temporal pattern of thalamocortical network activity over the course of spindles therefore reflects the engagement of distinct subnetworks at specific times across spindle epochs. We propose that early cortical cells serve a synchronizing role in the initiation and propagation of spindle activity, whereas the subsequent recruitment of late cells actively antagonizes the thalamic spindle generator by providing asynchronous feedback.

  14. Midline thalamic paraventricular nucleus neurons display diurnal variation in resting membrane potentials, conductances, and firing patterns in vitro

    Science.gov (United States)

    Kolaj, Miloslav; Zhang, Li; Rønnekleiv, Oline K.

    2012-01-01

    Neurons in the rodent midline thalamic paraventricular nucleus (PVT) receive inputs from brain stem and hypothalamic sites known to participate in sleep-wake and circadian rhythms. To evaluate possible diurnal changes in their excitability, we used patch-clamp techniques to record and examine the properties of neurons in anterior PVT (aPVT) in coronal rat brain slices prepared at zeitgeber time (ZT) 2–6 vs. ZT 14–18 and recorded at ZT 8.4 ± 0.2 (day) vs. ZT 21.2 ± 0.2 (night), the subjective quiet vs. aroused states, respectively. Compared with neurons recorded during the day, neurons from the night period were significantly more depolarized and exhibited a lower membrane conductance that in part reflected loss of a potassium-mediated conductance. Furthermore, these neurons were also significantly more active, with tonic and burst firing patterns. Neurons from each ZT period were assessed for amplitudes of two conductances known to contribute to bursting behavior, i.e., low-threshold-activated Ca2+ currents (IT) and hyperpolarization-activated cation currents (Ih). Data revealed that amplitudes of both IT and Ih were significantly larger during the night period. In addition, biopsy samples from the night period revealed a significant increase in mRNA for Cav3.1 and Cav3.3 low-threshold Ca2+ channel subtypes. Neurons recorded from the night period also displayed a comparative enhancement in spontaneous bursting at membrane potentials of approximately −60 mV and in burst firing consequent to hyperpolarization-induced low-threshold currents and depolarization-induced current pulses. These novel in vitro observations reveal that midline thalamic neurons undergo diurnal changes in their IT, Ih, and undefined potassium conductances. The underlying mechanisms remain to be characterized. PMID:22219029

  15. Effects of brain-stem and thalamic lesions on the corneal reflex: an electrophysiological and anatomical study.

    Science.gov (United States)

    Ongerboer de Visser, B W; Moffie, D

    1979-09-01

    In 9 patients with Wallenberg's lateral medullary syndrome, one patient with a midbrain lesion involving the right side of the tegmentum, and 2 patients with a thalamic lesion, corneal reflexes were investigated by a new electromyographic technique. The electrophysical results were compared with the results obtained by clinical observation. In the lateral medullary lesions the electrophysiologically obtained reflex responses showed four types of abnormality. Type A consisted of a bilateral delay and type B a bilateral absence of the corneal reflex response to stimulation on the affected side in combination with a normal reflex response on both sides when the cornea on the normal side was stimulated. Type C, which was present in one case, and type D which was seen in 3 cases, consisted of a bilateral absence of the corneal reflex upon stimulation on the affected side; stimulation on the unaffected side produced a normal reflex response on the intact side in combination with, respectively, a delay or absence of the corneal reflex response on the affected side. Comparison of the clinical observations with the electrophysiological findings revealed minor discrepancies in type A and B abnormalities. However, the electrophysiological type C and D abnormalities were not detected by clinical observation. These findings demonstrate that electrophysiological recording of the corneal reflex may reveal clinically undetectable abnormalities. From the electrophysiological findings it is concluded that the corneal reflex is conducted along medullary pathways running both ipsilaterally and contralaterally from the stimulated side before connecting, respectively, with the ipsilateral and contralateral facial nucleus. From the anatomical findings it is suggested that the ascending pathways from the spinal fifth nerve complex to the facial nuclei are located in the lateral reticular formation of the lower brain-stem. The normal corneal reflex responses in the presence of thalamic and

  16. Assessing Quantitative Changes in Intrinsic Thalamic Networks in Blast and Nonblast Mild Traumatic Brain Injury: Implications for Mechanisms of Injury.

    Science.gov (United States)

    Nathan, Dominic E; Bellgowan, Julie F; Oakes, Terrence R; French, Louis M; Nadar, Sreenivasan R; Sham, Elyssa B; Liu, Wei; Riedy, Gerard

    2016-06-01

    In the global war on terror, the increased use of improvised explosive devices has resulted in increased incidence of blast-related mild traumatic brain injury (mTBI). Diagnosing mTBI is both challenging and controversial due to heterogeneity of injury location, trauma intensity, transient symptoms, and absence of focal biomarkers on standard clinical imaging modalities. The goal of this study is to identify a brain biomarker that is sensitive to mTBI injury. Research suggests the thalamus may be sensitive to changes induced by mTBI. A significant number of connections to and from various brain regions converge at the thalamus. In addition, the thalamus is involved in information processing, integration, and regulation of specific behaviors and mood. In this study, changes in task-free thalamic networks as quantified by graph theory measures in mTBI blast (N = 186), mTBI nonblast (N = 80), and controls (N = 21) were compared. Results show that the blast mTBI group had significant hyper-connectivity compared with the controls and nonblast mTBI group. However, after controlling for post-traumatic stress symptoms (PTSS), the blast mTBI group was not different from the controls, but the nonblast mTBI group showed significant hypo-connectivity. The results suggest that there are differences in the mechanisms of injury related to mTBI as reflected in the architecture of the thalamic networks. However, the effect of PTSS and its relationship to mTBI is difficult to distinguish and warrants more research.

  17. CACNA1H missense mutations associated with amyotrophic lateral sclerosis alter Cav3.2 T-type calcium channel activity and reticular thalamic neuron firing.

    Science.gov (United States)

    Rzhepetskyy, Yuriy; Lazniewska, Joanna; Blesneac, Iulia; Pamphlett, Roger; Weiss, Norbert

    2016-11-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. In a recent study by Steinberg and colleagues, 2 recessive missense mutations were identified in the Cav3.2 T-type calcium channel gene (CACNA1H), in a family with an affected proband (early onset, long duration ALS) and 2 unaffected parents. We have introduced and functionally characterized these mutations using transiently expressed human Cav3.2 channels in tsA-201 cells. Both of these mutations produced mild but significant changes on T-type channel activity that are consistent with a loss of channel function. Computer modeling in thalamic reticular neurons suggested that these mutations result in decreased neuronal excitability of thalamic structures. Taken together, these findings implicate CACNA1H as a susceptibility gene in amyotrophic lateral sclerosis.

  18. Impaired Prefronto-Thalamic Functional Connectivity as a Key Feature of Treatment-Resistant Depression: A Combined MEG, PET and rTMS Study

    Science.gov (United States)

    Li, Cheng-Ta; Chen, Li-Fen; Tu, Pei-Chi; Wang, Shyh-Jen; Chen, Mu-Hong; Su, Tung-Ping; Hsieh, Jen-Chuen

    2013-01-01

    Prefrontal left-right functional imbalance and disrupted prefronto-thalamic circuitry are plausible mechanisms for treatment-resistant depression (TRD). Add-on repetitive transcranial magnetic stimulation (rTMS), effective in treating antidepressant-refractory TRD, was administered to verify the core mechanisms underlying the refractoriness to antidepressants. Thirty TRD patients received a 2-week course of 10-Hz rTMS to the left dorsolateral prefrontal cortex (DLPFC). Depression scores were evaluated at baseline (W0), and the ends of weeks 1, 2, and 14 (W14). Responders were defined as those who showed an objective improvement in depression scores ≥50% after rTMS. Left-right frontal alpha asymmetry (FAA) was measured by magnetoencephalography at each time point as a proxy for left-right functional imbalance. Prefronto-thalamic connections at W0 and W14 were assessed by studying couplings between prefrontal alpha waves and thalamic glucose metabolism (PWTMC, reflecting intact thalamo-prefrontal connectivity). A group of healthy control subjects received magnetoencephalography at W0 (N = 50) to study whether FAA could have a diagnostic value for TRD, or received both magnetoencephalography and positron-emission-tomography at W0 (N = 10) to confirm the existence of PWTMC in the depression-free state. We found that FAA changes cannot differentiate between TRD and healthy subjects or between responders and non-responders. No PWTMC were found in the TRD group at W0, whereas restitution of the PWTMC was demonstrated only in the sustained responders at W14 and euthymic healthy controls. In conclusion, we affirmed impaired prefronto-thalamic functional connections, but not frontal functional imbalance, as a core deficit in TRD. PMID:23936378

  19. The Human Thalamic Somatic Sensory Nucleus [Ventral Caudal (Vc)] Shows Neuronal Mechanoreceptor-Like Responses to Optimal Stimuli for Peripheral Mechanoreceptors

    OpenAIRE

    Weiss, N; Ohara, S; Johnson, K. O.; Lenz, F.A.

    2008-01-01

    Although the response of human cutaneous mechanoreceptors to controlled stimuli is well studied, it is not clear how these peripheral signals may be reflected in neuronal activity of the human CNS. We now test the hypothesis that individual neurons in the human thalamic principal somatic sensory nucleus [ventral caudal (Vc)] respond selectively to the optimal stimulus for one of the four mechanoreceptors. The optimal stimuli for particular mechanoreceptors were defined as follows: Pacinian co...

  20. Synaptic properties of thalamic and intracortical inputs to layer 4 of the first- and higher-order cortical areas in the auditory and somatosensory systems.

    Science.gov (United States)

    Lee, Charles C; Sherman, S Murray

    2008-07-01

    The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, "higher-order" thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these "higher-order" thalamic nuclei share similar synaptic properties with the "first-order" thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.

  1. Overexpression of GAP-43 in thalamic projection neurons of transgenic mice does not enable them to regenerate axons through peripheral nerve grafts.

    Science.gov (United States)

    Mason, M R; Campbell, G; Caroni, P; Anderson, P N; Lieberman, A R

    2000-09-01

    It is well established that some populations of neurons of the adult rat central nervous system (CNS) will regenerate axons into a peripheral nerve implant, but others, including most thalamocortical projection neurons, will not. The ability to regenerate axons may depend on whether neurons can express growth-related genes such as GAP-43, whose expression correlates with axon growth during development and with competence to regenerate. Thalamic projection neurons which fail to regenerate into a graft also fail to upregulate GAP-43. We have tested the hypothesis that the absence of strong GAP-43 expression by the thalamic projection neurons prevents them from regenerating their axons, using transgenic mice which overexpress GAP-43. Transgene expression was mapped by in situ hybridization with a digoxigenin-labeled RNA probe and by immunohistochemistry with a monoclonal antibody against the GAP-43 protein produced by the transgene. Many CNS neurons were found to express the mRNA and protein, including neurons of the mediodorsal and ventromedial thalamic nuclei, which rarely regenerate axons into peripheral nerve grafts. Grafts were implanted into the region of these nuclei in the brains of transgenic animals. Although these neurons strongly expressed the transgene mRNA and protein and transported the protein to their axon terminals, they did not regenerate axons into the graft, suggesting that lack of GAP-43 expression is not the only factor preventing thalamocortical neurons regenerating their axons. Copyright 2000 Academic Press.

  2. Cortico-Striatal-Thalamic Loop Circuits of the Salience Network: A Central Pathway in Psychiatric Disease and Treatment

    Science.gov (United States)

    Peters, Sarah K.; Dunlop, Katharine; Downar, Jonathan

    2016-01-01

    The salience network (SN) plays a central role in cognitive control by integrating sensory input to guide attention, attend to motivationally salient stimuli and recruit appropriate functional brain-behavior networks to modulate behavior. Mounting evidence suggests that disturbances in SN function underlie abnormalities in cognitive control and may be a common etiology underlying many psychiatric disorders. Such functional and anatomical abnormalities have been recently apparent in studies and meta-analyses of psychiatric illness using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM). Of particular importance, abnormal structure and function in major cortical nodes of the SN, the dorsal anterior cingulate cortex (dACC) and anterior insula (AI), have been observed as a common neurobiological substrate across a broad spectrum of psychiatric disorders. In addition to cortical nodes of the SN, the network’s associated subcortical structures, including the dorsal striatum, mediodorsal thalamus and dopaminergic brainstem nuclei, comprise a discrete regulatory loop circuit. The SN’s cortico-striato-thalamo-cortical loop increasingly appears to be central to mechanisms of cognitive control, as well as to a broad spectrum of psychiatric illnesses and their available treatments. Functional imbalances within the SN loop appear to impair cognitive control, and specifically may impair self-regulation of cognition, behavior and emotion, thereby leading to symptoms of psychiatric illness. Furthermore, treating such psychiatric illnesses using invasive or non-invasive brain stimulation techniques appears to modulate SN cortical-subcortical loop integrity, and these effects may be central to the therapeutic mechanisms of brain stimulation treatments in many psychiatric illnesses. Here, we review clinical and experimental evidence for abnormalities in SN cortico-striatal-thalamic loop circuits in major depression, substance use disorders (SUD

  3. Expression of N-methyl-D-aspartic acid 2A-B and 2B receptors in anterior thalamic nucleus and subiculum complex of rats

    Institute of Scientific and Technical Information of China (English)

    Yuanshan Fu; Xiaokai Ma; Xiaoling Yue; Bin Wang

    2008-01-01

    BACKGROUND: Glutamate acid ionotropic receptor N-methyl-D-aspartic acid (NMDA) takes part in long-term potentiation, thereby influencing the process of learning and memory.OBJECTIVE: To verify expression of NMDA 2A/B and 2B receptors in the anterior thalamic nucleus and subieulum complex of rats.DESIGN, TIME AND SETTING: A single-sample observation was performed at Department of Anatomy in Dalian Mcdical University (Dalian, Liaoning, China) from April to September in 2007.MATERIALS: Ten adult Wistar rats were used for this study, as well as rabbit anti-NMDA 2A/B and 2Bantibodies.METHODS: The rats were anesthetized and perfused, followed by brain resection and coronal sectioning of the brain tissue. A 1:3 series was selected for immunohistochemistry, using antibodies specific to NMDA 2A/B and 2B receptors. Photos were taken using the Nikon image analysis system.MAIN OUTCOME MEASURES: Expression and distribution of immunohistochemistry staining of NMDA 2A/B and 2B receptor subunits.RESULTS: There were a large number of NMDA 2A/B and 2B receptor-positive neurons distributed throughout the anterior dorsal thalamic nucleus. In the anterior ventral thalamic nucleus, distribution of positive neurons was rare, staining intensity was lighter, and cell bodies were smaller compared with the anterior dorsal thalamic nucleus. In the subiculum complex, staining intensity of NMDA 2A/B and 2B-positive neurons was weakest in the molecular layer and stronger in the pyramidal layer, in particular the region with large cell bodies adjacent to the molecular layer. In the multiform layer, more positive neurons of various sizes were detected.CONCLUSION: NMDA 2A/B and 2B receptor subunits were richly distributed in the anterior thalamic nucleus, with a small difference existing between the anterior dorsal nucleus and anterior ventral nucleus.These neurons were also differentially distributed within the three layers of the subiculum complex.

  4. Lmx1a is an activator of Rgs4 and Grb10 and is responsible for the correct specification of rostral and medial mdDA neurons.

    Science.gov (United States)

    Hoekstra, Elisa J; von Oerthel, Lars; van der Linden, Annemarie J A; Schellevis, Raymond D; Scheppink, Gerard; Holstege, Frank C P; Groot-Koerkamp, Marian J; van der Heide, Lars P; Smidt, Marten P

    2013-01-01

    The LIM homeodomain transcription factor Lmx1a is a very potent inducer of stem cells towards dopaminergic neurons. Despite several studies on the function of this gene, the exact in vivo role of Lmx1a in mesodiencephalic dopamine (mdDA) neuronal specification is still not understood. To analyse the genes functioning downstream of Lmx1a, we performed expression microarray analysis of LMX1A-overexpressing MN9D dopaminergic cells. Several interesting regulated genes were identified, based on their regulation in other previously generated expression arrays and on their expression pattern in the developing mdDA neuronal field. Post analysis through in vivo expression analysis in Lmx1a mouse mutant (dr/dr) embryos demonstrated a clear decrease in expression of the genes Grb10 and Rgs4, in and adjacent to the rostral and dorsal mdDA neuronal field and within the Lmx1a expression domain. Interestingly, the DA marker Vmat2 was significantly up-regulated as a consequence of increased LMX1A dose, and subsequent analysis on Lmx1a-mutant E14.5 and adult tissue revealed a significant decrease in Vmat2 expression in mdDA neurons. Taken together, microarray analysis of an LMX1A-overexpression cell system resulted in the identification of novel direct or indirect downstream targets of Lmx1a in mdDA neurons: Grb10, Rgs4 and Vmat2.

  5. Short-term anesthesia inhibits formalin-induced extracellular signal-regulated kinase (ERK) activation in the rostral anterior cingulate cortex but not in the spinal cord.

    Science.gov (United States)

    Tochiki, Keri K; Maiarù, Maria; Miller, James R C; Hunt, Stephen P; Géranton, Sandrine M

    2015-08-14

    The rostral anterior cingulate cortex (rACC) has been implicated in the negative affective response to injury, and importantly, it has been shown that activation of extracellular signal-regulated kinase (ERK) signaling in the rACC contributes to the full expression of the affective component of pain in rodents. In this study, we investigated whether administration of anesthesia at the time of injury could reduce phosphorylated-ERK (PERK) expression in the rACC, which might eliminate the negative affective component of noxious stimulation. Intraplantar hindpaw formalin stimulation, an aversive event in the awake animal, was given with or without general isoflurane anesthesia, and PERK expression was subsequently quantified in the rACC using immunohistochemistry. Furthermore, as numerous studies have demonstrated the importance of spinal ERK signaling in the regulation of nociceptive behaviour, we also examined PERK in the superficial dorsal horn of the spinal cord. Formalin injection with and without short-term (anesthesia induced the same level of PERK expression in spinal cord laminae I-II. However, PERK expression was significantly inhibited across all laminae of the rACC in animals anesthetized during formalin injection. The effect of anesthesia was such that levels of PERK were the same in formalin and sham treated anesthesized animals. This study is the first to demonstrate that isoflurane anesthesia can inhibit formalin-induced PERK in the rACC and therefore might eliminate the unpleasantness of restraint associated with awake hindpaw injection.

  6. A subset of μ-opioid receptor-expressing cells in the rostral ventromedial medulla contribute to thermal hyperalgesia in experimental neuropathic pain.

    Science.gov (United States)

    Mase, Hiroshi; Sakai, Atsushi; Sakamoto, Atsuhiro; Suzuki, Hidenori

    2011-05-01

    The rostral ventromedial medulla (RVM) is a major region for the descending modulation of pain at the spinal cord level, and neurons in the RVM have been implicated in the inhibition and facilitation of spinal nociceptive transmission. Although recent studies have established that the RVM facilitation of nociceptive transmission in the spinal cord contributes to neuropathic pain, the underlying mechanisms remain largely unknown. In the present study, we investigated the effects of kainic acid (KA)-induced RVM damage on neuropathic pain behavior and the expression of molecules implicated in pain modulation. KA was injected into the RVM midline region after neuropathic pain was established by chronic constrictive injury of the left sciatic nerve. Thermal hyperalgesia, but not mechanical allodynia, was persistently suppressed in the ipsilateral paw by a single KA injection into the RVM for at least the next 7 days in a rat neuropathic pain model. KA injection alone did not affect the nocifensive responses to mechanical and thermal stimuli on the intact side. Immunohistochemical analysis revealed that KA injection into the RVM significantly reduced the number of immunoreactive neurons for μ-opioid receptors, but not tryptophan hydroxylase, in association with the analgesic effect. These results suggest that a subset of RVM neurons expressing μ-opioid receptors contribute to the maintenance of thermal hyperalgesia in neuropathic pain.

  7. Regulation of the sympathetic nervous system by nitric oxide and oxidative stress in the rostral ventrolateral medulla: 2012 Academic Conference Award from the Japanese Society of Hypertension.

    Science.gov (United States)

    Kishi, Takuya

    2013-10-01

    Sympathoexcitation has an important role in the pathogenesis of hypertension. Previous studies have demonstrated that nitric oxide (NO) and/or oxidative stress in the brain are important for the regulation of the sympathetic nervous system. We have investigated the role of NO derived from an overexpression of endothelial NO synthase (eNOS) or oxidative stress in the rostral ventrolateral medulla (RVLM), which is known as a vasomotor center in the brainstem, on the regulation of the sympathetic nervous system. Our results indicated that NO derived from an overexpression of eNOS in the RVLM caused sympathoinhibition via an increase in γ-amino butyric acid and that angiotensin II type 1 receptor (AT1R)-induced oxidative stress in the RVLM caused sympathoexcitation. We also demonstrated that oxidative stress in the RVLM caused sympathoexcitation via interactions with NO, effects on the signal transduction or apoptosis of the astrocytes. Furthermore, several orally administered AT1R blockers have been found to cause sympathoinhibition via a reduction in oxidative stress through the blockade of AT1R in the RVLM of hypertensive rats. In conclusion, our studies suggest that the increase in AT1R-induced oxidative stress and/or the decrease in NO in the RVLM mainly cause sympathoexcitation in hypertension.

  8. Effects of a metabotropic glutamate receptor subtype 7 negative allosteric modulator in the periaqueductal grey on pain responses and rostral ventromedial medulla cell activity in rat.

    Science.gov (United States)

    Palazzo, Enza; Marabese, Ida; Luongo, Livio; Boccella, Serena; Bellini, Giulia; Giordano, Maria Elvira; Rossi, Francesca; Scafuro, Mariantonietta; Novellis, Vito de; Maione, Sabatino

    2013-09-03

    The metabotropic glutamate receptor 7 (mGluR7) negative allosteric modulator, 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP), was locally microinjected into the ventrolateral periaqueductal gray (VL PAG) and the effect on pain responses in formalin and spare nerve injury (SNI) -induced neuropathic pain models was monitored in the rat. The activity of rostral ventromedial medulla (RVM) "pronociceptive" ON and "antinociceptive" OFF cells was also evaluated. Intra-VL PAG MMPIP blocked the first and second phase of nocifensive behaviour in the formalin pain model. MMPIP increased the tail flick latency and simultaneously increased the activity of the OFF cells while inhibiting that of ON cells in rats with SNI of the sciatic nerve. MMPIP failed to modify nociceptive responses and associated RVM ON and OFF cell activity in sham rats. An increase in mGluR7 gene, protein and staining, the latter being associated with vesicular glutamate transporter-positive profiles, has been found in the VL PAG in SNI rats. Blockade of mGluR7 within the VL PAG has an antinociceptive effect in formalin and neuropathic pain models. VL PAG mGluR7 blockade offers a target for dis-inhibiting the VL PAG-RVM pathway and silencing pain in inflammatory and neuropathic pain models.

  9. Microinjection of resveratrol into rostral ventrolateral medulla decreases sympathetic vasomotor tone through nitric oxide and intracellular Ca2+in anesthetized male rats

    Institute of Scientific and Technical Information of China (English)

    Hui-juan MA; Ya-kun CAO; Yi-xian LIU; Ru WANG; Yu-ming WU

    2008-01-01

    Aim: To define the effect of resveratrol (RES) on the central regulation of blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA). Methods: RES was microinjected into the rostral ventrolateral medulla (RVLM), and BP, HR, and RSNA were recorded simultaneously in anesthetized rats. Results: A microinjection of RES (20, 40, and 80 μmol/L, 0.2μL) into the RVLM dose depen- dently decreased BP, HR, and RSNA. Pretreatment with an anti-estrogen tamoxifen (100 μmol/L, 0.2 μL) did not affect the effects of RES. Pretreatment with NG-nitro- L-arginine methyl ester (100/Jmol/L, 0.2 μL), an inhibitor of nitric oxide (NO) synthase, could completely abolish the effect of RES. A prior microinjection of Bay K8644 (500 nmol/L, 0.2 μL), an agonist of calcium channels, could also abro- gate the effect of RES. Prior administration of a potent inhibitor of tyrosine phosphatase, sodium orthovanadate (l mmol/L, 0.2 μL), could partially attenuate the inhibitory effect of RES. Conclusion: The results suggest that a microinjec- tion of RES into the RVLM inhibits BE HR, and RSNA. The effects may be mediated by NO synthesis and a decrease in Ca2+ influx, in which protein tyrosine kinase is involved.

  10. Mechanical Stimulus-Induced Wthdrawal Behavior Increases Subsequent Pre-Stimulus Local Field Potential Power in the Rostral Anterior Cingulate Cortex in Unanesthetized Rats.

    Science.gov (United States)

    Shen, Zui; Sun, Jing; Liu, Boyi; Jiang, Yongliang; Wu, Yuanyuan; Wang, Jialing; Shao, Xiaomei; Fang, Jianqiao

    2017-03-02

    BACKGROUND The rostral anterior cingulate cortex (rACC) is important in pain expectation. Previous studies demonstrated that mechanical stimulus-induced withdrawal behaviors are spinally-mediated nocifensive reflexes in rats, but it is not known whether pain expectation is influenced by withdrawal behaviors. MATERIAL AND METHODS We reanalyzed previous mechanosensitivity measurements of 244 rats measured 5 times in succession. To study neural oscillation in the rACC, 1 recording microwire array was surgically implanted. Then, we simultaneously recorded the local field potential (LFP) of the rACC over the course of multiple withdrawal behaviors in unanesthetized rats. RESULTS From our previous withdrawal behavioral data in 244 rats, we observed that the distributions of paw withdrawal thresholds (PWTs) were denser and more concentrated after the first withdrawal behavior. Compared to the first mechanical stimulus, increased neuronal synchrony and a stronger delta band component existed in each pre-stimulus LFP in the rACC during subsequent stimuli. CONCLUSIONS Pain expectation could be involved in withdrawal behaviors, which is related to increased total power and delta band power of the subsequent pre-stimulus LFPs in the rACC.

  11. Crossed Aphasia and Visuo-Spatial Neglect Following a Right Thalamic Stroke: A Case Study and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Lieve De Witte

    2008-01-01

    Full Text Available Crossed aphasia in dextrals (CAD following pure subcortical lesions is rare. This study describes a right-handed patient with an ischemic lesion in the right thalamus. In the post-acute phase of the stroke, a unique combination of ‘crossed thalamic aphasia’ was found with left visuo-spatial neglect and constructional apraxia. On the basis of the criteria used in Mariën et al. [67], this case-report is the first reliable representative of vascular CAD following an isolated lesion in the right thalamus. Furthermore, this paper presents a detailed analysis of linguistic and cognitive impairments of ‘possible’ and 'reliable' subcortical CAD-cases published since 1975. Out of 25 patients with a pure subcortical lesion, nine cases were considered as ‘possibly reliable or reliable’. A review of these cases reveals that: (1 demographic data are consistent with the general findings for the entire group of vascular CAD, (2 the neurolinguistic findings do not support the data in the general CAD-population with regard to (a the high prevalence of transcortical aphasia and (b the tendency towards a copresence of an oral versus written language dissociation and a ‘mirror-image’ lesion-aphasia profile, (3 subcortical CAD is not a transient phenomenon, (4 the lesion-aphasia correlations are not congruent with the high incidence of anomalous cases in the general CAD-population, (5 neuropsychological impairments may accompany subcortical CAD.

  12. The role of cutaneous afferents from the distal hindlimb in the regulation of the step cycle of thalamic cats.

    Science.gov (United States)

    Duysens, J; Pearson, K G

    1976-01-26

    The pad and the plantar surface of the foot were stimulated electrically in thalamic cats. Weak stimulation evoked an extensor reflex in the animal at rest. The same stimuli in a spontaneously walking animal applied during the stance phase produced an increase both in amplitude and duration of the ongoing extensor activity. When given during the swing phase, the stimuli either prolonged the ongoing flexor activity and/or shortened the following extensor burst. These changes in flexor and extensor burst duration were reflected in changes in the step cycle duration. Similar results were seen with direct stimulation of the sural nerve. For the latter experiments the ipsilateral hindlimb was fixed and denervated except for the ankle extensors and flexors, which showed rhythmic contractions correlated normally with the walking movements of the three remaining limbs. At rest, threshold stimulation of the sural nerve evoked a reflex contraction in the triceps surae of the fixed leg. The same stimuli applied during the contraction phase of the fixed triceps surae during walking resulted in a larger and longer extensor contraction and a delay of the following flexion. Stimulation during the relaxation phase of the fixed triceps surae reduced the duration of the following contraction phase. The findings are discussed in relation to the possible role of cutaneous input during locomotion.

  13. Differential Modification of Cortical and Thalamic Projections to Cat Primary Auditory Cortex Following Early- and Late-Onset Deafness.

    Science.gov (United States)

    Chabot, Nicole; Butler, Blake E; Lomber, Stephen G

    2015-10-15

    Following sensory deprivation, primary somatosensory and visual cortices undergo crossmodal plasticity, which subserves the remaining modalities. However, controversy remains regarding the neuroplastic potential of primary auditory cortex (A1). To examine this, we identified cortical and thalamic projections to A1 in hearing cats and those with early- and late-onset deafness. Following early deafness, inputs from second auditory cortex (A2) are amplified, whereas the number originating in the dorsal zone (DZ) decreases. In addition, inputs from the dorsal medial geniculate nucleus (dMGN) increase, whereas those from the ventral division (vMGN) are reduced. In late-deaf cats, projections from the anterior auditory field (AAF) are amplified, whereas those from the DZ decrease. Additionally, in a subset of early- and late-deaf cats, area 17 and the lateral posterior nucleus (LP) of the visual thalamus project concurrently to A1. These results demonstrate that patterns of projections to A1 are modified following deafness, with statistically significant changes occurring within the auditory thalamus and some cortical areas. Moreover, we provide anatomical evidence for small-scale crossmodal changes in projections to A1 that differ between early- and late-onset deaf animals, suggesting that potential crossmodal activation of primary auditory cortex differs depending on the age of deafness onset.

  14. System identification of the nonlinear dynamics in the thalamocortical circuit in response to patterned thalamic microstimulation in-vivo

    Science.gov (United States)

    Millard, Daniel C; Wang, Qi; Gollnick, Clare A; Stanley, Garrett B

    2013-01-01

    Objective Nonlinear system identification approaches were used to develop a dynamical model of the network level response to patterns of microstimulation in-vivo. Approach The thalamocortical circuit of the rodent vibrissa pathway was the model system, with voltage sensitive dye imaging capturing the cortical response to patterns of stimulation delivered from a single electrode in the ventral posteromedial thalamus. The results of simple paired stimulus experiments formed the basis for the development of a phenomenological model explicitly containing nonlinear elements observed experimentally. The phenomenological model was fit using datasets obtained with impulse train inputs, Poisson-distributed in time and uniformly varying in amplitude. Main Results The phenomenological model explained 58% of the variance in the cortical response to out of sample patterns of thalamic microstimulation. Furthermore, while fit on trial averaged data, the phenomenological model reproduced single trial response properties when simulated with noise added into the system during stimulus presentation. The simulations indicate that the single trial response properties were dependent on the relative sensitivity of the static nonlinearities in the two stages of the model, and ultimately suggest that electrical stimulation activates local circuitry through linear recruitment, but that this activity propagates in a highly nonlinear fashion to downstream targets. Significance The development of nonlinear dynamical models of neural circuitry will guide information delivery for sensory prosthesis applications, and more generally reveal properties of population coding within neural circuits. PMID:24162186

  15. System identification of the nonlinear dynamics in the thalamocortical circuit in response to patterned thalamic microstimulation in vivo

    Science.gov (United States)

    Millard, Daniel C.; Wang, Qi; Gollnick, Clare A.; Stanley, Garrett B.

    2013-12-01

    Objective. Nonlinear system identification approaches were used to develop a dynamical model of the network level response to patterns of microstimulation in vivo. Approach. The thalamocortical circuit of the rodent vibrissa pathway was the model system, with voltage sensitive dye imaging capturing the cortical response to patterns of stimulation delivered from a single electrode in the ventral posteromedial thalamus. The results of simple paired stimulus experiments formed the basis for the development of a phenomenological model explicitly containing nonlinear elements observed experimentally. The phenomenological model was fit using datasets obtained with impulse train inputs, Poisson-distributed in time and uniformly varying in amplitude. Main results. The phenomenological model explained 58% of the variance in the cortical response to out of sample patterns of thalamic microstimulation. Furthermore, while fit on trial-averaged data, the phenomenological model reproduced single trial response properties when simulated with noise added into the system during stimulus presentation. The simulations indicate that the single trial response properties were dependent on the relative sensitivity of the static nonlinearities in the two stages of the model, and ultimately suggest that electrical stimulation activates local circuitry through linear recruitment, but that this activity propagates in a highly nonlinear fashion to downstream targets. Significance. The development of nonlinear dynamical models of neural circuitry will guide information delivery for sensory prosthesis applications, and more generally reveal properties of population coding within neural circuits.

  16. rKv1.2 overexpression in the central medial thalamic area decreases caffeine-induced arousal.

    Science.gov (United States)

    Cazzin, C; Piccoli, L; Massagrande, M; Garbati, N; Michielin, F; Knaus, H-G; Ring, C J A; Morrison, A D; Merlo-Pich, E; Rovo, Z; Astori, S; Lüthi, A; Corti, C; Corsi, M

    2011-11-01

    The voltage-gated potassium channel Kv1.2 belongs to the shaker-related family and has recently been implicated in the control of sleep profile on the basis of clinical and experimental evidence in rodents. To further investigate whether increasing Kv1.2 activity would promote sleep occurrence in rats, we developed an adeno-associated viral vector that induces overexpression of rat Kv1.2 protein. The viral vector was first evaluated in vitro for its ability to overexpress rat Kv1.2 protein and to produce functional currents in infected U2OS cells. Next, the adeno-associated Kv1.2 vector was injected stereotaxically into the central medial thalamic area of rats and overexpression of Kv1.2 was showed by in situ hybridization, ex vivo electrophysiology and immunohistochemistry. Finally, the functional effect of Kv1.2 overexpression on sleep facilitation was investigated using telemetry system under normal conditions and following administration of the arousing agent caffeine, during the light phase. While no differences in sleep profile were observed between the control and the treated animals under normal conditions, a decrease in the pro-arousal effect of caffeine was seen only in the animals injected with the adeno-associated virus-Kv1.2 vector. Overall, our data further support a role of the Kv1.2 channel in the control of sleep profile, particularly under conditions of sleep disturbance.

  17. The correlation of the thalamic lesions on MRI with cerebral cortical blood flow in patients with lacunar infarction

    Energy Technology Data Exchange (ETDEWEB)

    Nabatame, Hidehiko; Nakamura, Kazuo; Matsuda, Minoru; Fujimoto, Naoki [Shiga Medical Center, Moriyama (Japan); Fukuyama, Hidenao

    1995-07-01

    We performed MRI and measured cerebral blood flow (CBF) using {sup 123}I-IMP SPECT microsphere model in twenty three right-handed patients with lacunar infarction. Twelve of 23 patients showed chronic deterioration of dysarthria and gait disturbance. The mental function of the patients was evaluated by the Mini-Mental State (MMS) examination. The area of high intensity on T2-weighted images was quantitatively analyzed in the cerebral white matter (WM), lenticular nucleus (LN) and thalamus (THA). The score of MMS was positively correlated with the local CBF in the bilateral frontal, parietal, temporal and occipital cortices (p<0.05). Also, the area of high intensity in the left THA showed a significant negative correlation with local CBF of the bilateral frontal, parietal, temporal and occipital cortices (p<0.001). The high intensity areas of the bilateral LN, right WM and right THA had a significant but weaker negative correlation with local CBF of some cortices. These findings suggest that thalamic lesions on the dominant side play an important role in the reduction of cortical blood flow and the deterioration of mental functions in patients with lacunar infarction. (author).

  18. A novel turning behavior control method for rat-robot through the stimulation of ventral posteromedial thalamic nucleus.

    Science.gov (United States)

    Xu, Kedi; Zhang, Jiacheng; Zhou, Hong; Lee, Ji Chao Tristan; Zheng, Xiaoxiang

    2016-02-01

    The concept of a rat-robot was initially introduced in 2002, bringing to the field, a novel area of research using modern research into neuroscience and robotics. This paper brings to the table, a study into the method best used for navigation systems in a rat-robot. Current research is epitomized by the use of reward-based spatial navigation, combining the concept of an induced reward sensation as well as a 'virtual touch' sensation to control the movement of the rat-robot. However, such methods are plagued by limitations affecting the success rate as well as preparation procedures which may have varying effects on different rats, even under similar conditions. Hence, this paper studies the stimulation of two different portions of the brain to induce a turning motion within the rat, namely the Ventral Posteromedial (VPM) thalamic nucleus as well as the Barrel-Field (BF) cortex and demonstrates the preferential usage of VPM as the choice use of navigational control in a rat-robot.

  19. Syndrome-Specific Deficits of Performance and Effects of Practice on Arm Movements with Deafferentation due to Posterior Thalamic Lesion

    Directory of Open Access Journals (Sweden)

    Thomas Platz

    1997-01-01

    Full Text Available Aiming and tapping movements were analysed repeatedly over a three-week period in a patient who was hemideafferented due to an ischaemic posterior thalamic lesion. Contrasting behaviour observed in six healthy subjects, nine hemiparetic patients and one patient with hemianopic stroke, allowed the determination of behavioural deficits related to deafferentation. Finger tapping was not impaired specifically and did not improve with practice in the deafferented patient. When aiming movements were investigated, accuracy of the first, largely preprogrammed, phase of movement and timing of the late homing-in phase were impaired specifically in the deafferented patient. Practice led to a step-like change in preprogramming amplitude of the ballistic movement component, a gradual improvement of temporal efficiency of the early movement phase and a more marked improvement of the homing-in phase. Qualitatively comparable but quantitatively less marked effects of practice were documented for hemiparetic patients. These results demonstrated that deafferentation affects preprogrammed aspects of movement and those influenced by current control and that motor learning is possible with central deafferentation, even for aspects of performance that are impaired specifically. It is postulated that motor learning was mediated by changes in strategy (motor programming and improved efficiency of intact motor control processes (visuomotor control.

  20. Experimental evidence and modeling studies support a synchronizing role for electrical coupling in the cat thalamic reticular neurons in vivo

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    Fuentealba, Pablo; Crochet, Sylvain; Timofeev, Igor; Bazhenov, Maxim; Sejnowski, Terrence J.; Steriade, Mircea

    2010-01-01

    Thalamic reticular (RE) neurons are crucially implicated in brain rhythms. Here, we report that RE neurons of adult cats, recorded and stained intracellularly in vivo, displayed spontaneously occurring spikelets, which are characteristic of central neurons that are coupled electrotonically via gap junctions. Spikelets occurred spontaneously during spindles, an oscillation in which RE neurons play a leading role, as well as during interspindle lulls. They were significantly different from excitatory postsynaptic potentials and also distinct from fast prepotentials that are presumably dendritic spikes generated synaptically. Spikelets were strongly reduced by halothane, a blocker of gap junctions. Multi-site extracellular recordings performed before, during and after administration of halothane demonstrated a role for electrical coupling in the synchronization of spindling activity within the RE nucleus. Finally, computational models of RE neurons predicted that gap junctions between these neurons could mediate the spread of low-frequency activity at great distances. These experimental and modeling data suggest that electrotonic coupling within the RE nucleus plays an important role in the generation and synchronization of low-frequency (spindling) activities in the thalamus. PMID:15245484

  1. Efficacy of T2*-Weighted Gradient-Echo MRI in Early Diagnosis of Cerebral Venous Thrombosis with Unilateral Thalamic Lesion

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    Shingo Mitaki

    2013-01-01

    Full Text Available Cerebral venous thrombosis (CVT is an uncommon cause of stroke with diverse etiologies and varied clinical presentations. Because of variability in clinical presentation and neuroimaging, CVT remains a diagnostic challenge. Recently, some studies have highlighted the value of T2*-weighted gradient-echo MRI (T2*WI in the diagnosis of CVT. We report the case of a 79-year-old woman with CVT due to a hypercoagulable state associated with cancer. On the initial T2-weighted image (T2WI, there was a diffuse high-intensity lesion in the right thalamus, extending into the posterior limb of the internal capsule and midbrain. T2*WI showed diminished signal and enlargement of the right basilar vein and the vein of Galen. Even though there is a wide range of differential diagnoses in unilateral thalamic lesions, and a single thalamus lesion is a rare entity of CVT, based on T2*WI findings we could make an early diagnosis and perform treatment. Our case report suggests that T2*WI could detect thrombosed veins and be a useful method of early diagnosis in CVT.

  2. Deriving theoretical phase locking values of a coupled cortico-thalamic neural mass model using center manifold reduction.

    Science.gov (United States)

    Ogawa, Yutaro; Yamaguchi, Ikuhiro; Kotani, Kiyoshi; Jimbo, Yasuhiko

    2017-02-24

    Cognitive functions such as sensory processing and memory processes lead to phase synchronization in the electroencephalogram or local field potential between different brain regions. There are a lot of computational researches deriving phase locking values (PLVs), which are an index of phase synchronization intensity, from neural models. However, these researches derive PLVs numerically. To the best of our knowledge, there have been no reports on the derivation of a theoretical PLV. In this study, we propose an analytical method for deriving theoretical PLVs from a cortico-thalamic neural mass model described by a delay differential equation. First, the model for generating neural signals is transformed into a normal form of the Hopf bifurcation using center manifold reduction. Second, the normal form is transformed into a phase model that is suitable for analyzing synchronization phenomena. Third, the Fokker-Planck equation of the phase model is derived and the phase difference distribution is obtained. Finally, the PLVs are calculated from the stationary distribution of the phase difference. The validity of the proposed method is confirmed via numerical simulations. Furthermore, we apply the proposed method to a working memory process, and discuss the neurophysiological basis behind the phase synchronization phenomenon. The results demonstrate the importance of decreasing the intensity of independent noise during the working memory process. The proposed method will be of great use in various experimental studies and simulations relevant to phase synchronization, because it enables the effect of neurophysiological changes on PLVs to be analyzed from a mathematical perspective.

  3. Repeated head trauma is associated with smaller thalamic volumes and slower processing speed: the Professional Fighters' Brain Health Study.

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    Bernick, Charles; Banks, Sarah J; Shin, Wanyong; Obuchowski, Nancy; Butler, Sam; Noback, Michael; Phillips, Michael; Lowe, Mark; Jones, Stephen; Modic, Michael

    2015-08-01

    Cumulative head trauma may alter brain structure and function. We explored the relationship between exposure variables, cognition and MRI brain structural measures in a cohort of professional combatants. 224 fighters (131 mixed martial arts fighters and 93 boxers) participating in the Professional Fighters Brain Health Study, a longitudinal cohort study of licensed professional combatants, were recruited, as were 22 controls. Each participant underwent computerised cognitive testing and volumetric brain MRI. Fighting history including years of fighting and fights per year was obtained from self-report and published records. Statistical analyses of the baseline evaluations were applied cross-sectionally to determine the relationship between fight exposure variables and volumes of the hippocampus, amygdala, thalamus, caudate, putamen. Moreover, the relationship between exposure and brain volumes with cognitive function was assessed. Increasing exposure to repetitive head trauma measured by number of professional fights, years of fighting, or a Fight Exposure Score (FES) was associated with lower brain volumes, particularly the thalamus and caudate. In addition, speed of processing decreased with decreased thalamic volumes and with increasing fight exposure. Higher scores on a FES used to reflect exposure to repetitive head trauma were associated with greater likelihood of having cognitive impairment. Greater exposure to repetitive head trauma is associated with lower brain volumes and lower processing speed in active professional fighters. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Histogenesis of olfactory bulb and rostral migration stream in mice%小鼠嗅球以及吻侧迁移流的发生

    Institute of Scientific and Technical Information of China (English)

    高文静; 王志新; 徐高磊; 邓锦波; 高晓群

    2012-01-01

    目的:探讨嗅球结构和吻侧迁移流(RMS)的发生及其中神经干细胞的变化趋势.方法:利用H-E染色、Nissl染色标记嗅球形态结构,BrdU免疫荧光技术观察吻侧迁移流中增殖的神经干细胞.结果:嗅球组织结构的发生:胚胎期,嗅球各层的结构轮廓尚未发育完全;生后3d时,各层结构虽然发育完善,但层与层之间的交界处模糊不清,生后5d时,整个嗅球结构发育已经完善,也就意味着嗅觉系统发育成熟.迁移流的发生:胚胎初期,侧脑室是一个很大的空腔,管腔膜上布满了增殖的神经于细胞,脑室下区延伸入中空的嗅球中,之后管腔闭合,形成了原始的吻侧迁移流;出生时,吻侧迁移流中的细胞密度达到最大值,之后逐渐降低,直至消失.结论:嗅球片层化结构是从无到有,从不成熟到成熟的过程.吻侧迁移流的发生是侧脑室腔的闭合和室管下层上神经干细胞遗留的痕迹.%Objective:To discuss the structure of the olfactory bulb (OB), the occurrence of the rostral migration streams (RMS) and the change trend of neural stem cells in RMS. Methods: The histological structure of the OB was marked by the methods of HE staining and Nissl staining. Using bromodeoxyuridine (BrdU)-immunofluorescence to observe the proliferation of neural stem cells in RMS. Results: (1)In the embryonic period, the outline of the structure of the OB layers was not fully developed yet. On the third day after birth the structure developed well, but the junctions between layers were blurred. In P5, the development of the entire olfactory bulb was improved. (2)In the early embryo, the lateral ventricle was a large cavity. The lumen membrance was full of the proliferation of neural stem cells. The subventricular zone extended into the hollow of OB, and then closed the lumen, forming the original rostral migration stream. In P0, the cell density in RMS reached its maximum value, then gradually reduced until it

  5. Mapping and Analysis of the Connectome of Sympathetic Premotor Neurons in the Rostral Ventrolateral Medulla of the Rat Using a Volumetric Brain Atlas

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    Dempsey, Bowen; Le, Sheng; Turner, Anita; Bokiniec, Phil; Ramadas, Radhika; Bjaalie, Jan G.; Menuet, Clement; Neve, Rachael; Allen, Andrew M.; Goodchild, Ann K.; McMullan, Simon

    2017-01-01

    Spinally projecting neurons in the rostral ventrolateral medulla (RVLM) play a critical role in the generation of vasomotor sympathetic tone and are thought to receive convergent input from neurons at every level of the neuraxis; the factors that determine their ongoing activity remain unresolved. In this study we use a genetically restricted viral tracing strategy to definitively map their spatially diffuse connectome. We infected bulbospinal RVLM neurons with a recombinant rabies variant that drives reporter expression in monosynaptically connected input neurons and mapped their distribution using an MRI-based volumetric atlas and a novel image alignment and visualization tool that efficiently translates the positions of neurons captured in conventional photomicrographs to Cartesian coordinates. We identified prominent inputs from well-established neurohumoral and viscero-sympathetic sensory actuators, medullary autonomic and respiratory subnuclei, and supramedullary autonomic nuclei. The majority of inputs lay within the brainstem (88–94%), and included putative respiratory neurons in the pre-Bötzinger Complex and post-inspiratory complex that are therefore likely to underlie respiratory-sympathetic coupling. We also discovered a substantial and previously unrecognized input from the region immediately ventral to nucleus prepositus hypoglossi. In contrast, RVLM sympathetic premotor neurons were only sparsely innervated by suprapontine structures including the paraventricular nucleus, lateral hypothalamus, periaqueductal gray, and superior colliculus, and we found almost no evidence of direct inputs from the cortex or amygdala. Our approach can be used to quantify, standardize and share complete neuroanatomical datasets, and therefore provides researchers with a platform for presentation, analysis and independent reanalysis of connectomic data.

  6. A quantification of the relationship between neuronal responses in the rat rostral ventromedial medulla and noxious stimulation-evoked withdrawal reflexes.

    Science.gov (United States)

    Devonshire, I M; Kwok, C H T; Suvik, A; Haywood, A R; Cooper, A H; Hathway, G J

    2015-07-01

    The rostral ventromedial medulla (RVM) regulates a range of involuntary behaviours but is most often associated with nociception via the action of pronociceptive ON cells and antinociceptive OFF cells. The phasic responses of ON and OFF cells determine whether or not incoming noxious signals provoke a withdrawal reflex, and previous studies have suggested that reflex RVM activity patterns actively shape motor output. Here we challenged the model by using juvenile rats, which are known to exhibit markedly different reflex responses compared with adults. By recording single-cell activity in the RVM and the electromyography responses of hindlimb flexor muscles to noxious thermal stimulation we found that the juvenile reflex had a shorter onset latency, was larger in amplitude and exhibited a decreased rise time compared with the adult reflex. The responses of ON and OFF cells faithfully tracked the shorter onset latency of the reflex by also responding earlier and, thus, still preceded the reflex. However, neither the reflex amplitude nor the ongoing response profile was predicted by the firing rate of RVM cells in either age group. Instead we found a close correspondence between RVM activity and the reflex only during the initiation of the response. Furthermore, the short rise time of the juvenile reflex was reflected in higher rates of change of both ON and OFF cell firing. Our data suggest that the RVM is associated only with the initiation of reflexes and does not shape ongoing muscle activity, which is more likely to be subserved by downstream spinal processes. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  7. Oral L-histidine exerts antihypertensive effects via central histamine H3 receptors and decreases nitric oxide content in the rostral ventrolateral medulla in spontaneously hypertensive rats.

    Science.gov (United States)

    Toba, Hiroe; Nakamori, Ayako; Tanaka, Yoshimi; Yukiya, Ryosuke; Tatsuoka, Keisuke; Narutaki, Masako; Tokitaka, Masaaki; Hariu, Hitoshi; Kobara, Miyuki; Nakata, Tetsuo

    2010-01-01

    1. L-histidine is generally found in meat, poultry and fish. To investigate its effects on blood pressure, L-histidine was administered to 9-week-old spontaneously hypertensive rats (SHR). 2. Oral administration of L-histidine (100 mg / kg) increased histamine content in cerebrospinal fluid and reduced mean arterial pressure (MAP) in SHR. Intracerebroventricular injection of L-histidine (0.01 microg / 5 microL) also caused a decrease in MAP, which was reversed by cotreatment with the histamine H3 receptor antagonist thioperamide (20.4 microg / 5 microL, i.c.v.). There was a significant, time-dependent increase (over 6 h) in the NOx (NO2- + NO3-) content of the dialysate from the rostral ventrolateral medulla (RVLM), a major vasomotor centre, after oral administration of L-histidine. 3. In another experiment, SHR were treated with l-histidine (100 mg / kg) twice a day for 4 weeks. Chronic treatment with L-histidine inhibited the age-dependent increases in systolic blood pressure and urinary noradrenaline excretion seen in vehicle-treated SHR. Conversely, intracerebroventricular injection of thioperamide (20.4 microg / 5 microL, i.c.v.) reversed the decrease in MAP in response to L-histidine in SHR. 4. Reverse transcription-polymerase chain reaction analysis revealed that the aortic expression of angiotensin-converting enzyme mRNA was suppressed by chronic treatment with L-histidine. 5. These results suggest that L-histidine decreases blood pressure by attenuating sympathetic output via the central histamine H3 receptor in SHR. In addition, the antihypertensive effects of L-histidine appear to be associated with an increase in nitric oxide in the RVLM.

  8. Excitatory amino acid receptor blockade within the caudal pressor area and rostral ventrolateral medulla alters cardiovascular responses to nucleus raphe obscurus stimulation in rats

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    Silva N.F.

    2002-01-01

    Full Text Available Pressor responses elicited by stimulation of the nucleus raphe obscurus (NRO depend on the integrity of the rostral ventrolateral medulla (RVLM. Therefore, to test the participation of excitatory amino acid (EAA receptors in the cardiovascular responses evoked by NRO stimulation (1 ms, 100 Hz, 40-70 µA, for 10 s, the EAA antagonist kynurenic acid (Kyn was microinjected at different sites in the ventrolateral medullar surface (2.7 nmol/200 nl of male Wistar rats (270-320 g, N = 39 and NRO stimulation was repeated. The effects of NRO stimulation were: hypertension (deltaMAP = +43 ± 1 mmHg, P<0.01, bradycardia (deltaHR = -30 ± 7 bpm, P<0.01 and apnea. Bilateral microinjection of Kyn into the RVLM, which did not change baseline parameters, almost abolished the bradycardia induced by NRO stimulation (deltaHR = -61 ± 3 before vs -2 ± 3 bpm after Kyn, P<0.01, N = 7. Unilateral microinjection of Kyn into the CVLM did not change baseline parameters or reduce the pressor response to NRO stimulation (deltaMAP = +46 ± 5 before vs +48 ± 5 mmHg after Kyn, N = 6. Kyn bilaterally microinjected into the caudal pressor area reduced blood pressure and heart rate and almost abolished the pressor response to NRO stimulation (deltaMAP = +46 ± 4 mmHg before vs +4 ± 2 mmHg after Kyn, P<0.01, N = 7. These results indicate that EAA receptors on the medullary ventrolateral surface play a role in the modulation of the cardiovascular responses induced by NRO stimulation, and also suggest that the RVLM participates in the modulation of heart rate responses and that the caudal pressor area modulates the pressor response following NRO stimulation.

  9. Nontranscriptional activation of PI3K/Akt signaling mediates hypotensive effect following activation of estrogen receptor β in the rostral ventrolateral medulla of rats

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    Wu Kay LH

    2012-08-01

    Full Text Available Abstract Background Estrogen acts on the rostral ventrolateral medulla (RVLM, where sympathetic premotor neurons are located, to elicit vasodepressor effects via an estrogen receptor (ERβ-dependent mechanism. We investigated in the present study nontranscriptional mechanism on cardiovascular effects following activation of ERβ in the RVLM, and delineated the involvement of phosphatidylinositol 3-kinase (PI3K/serine/threonine kinase (Akt signaling pathway in the effects. Methods In male Sprague–Dawley rats maintained under propofol anesthesia, changes in arterial pressure, heart rate and sympathetic neurogenic vasomotor tone were examined after microinjection bilaterally into RVLM of 17β-estradiol (E2β or a selective ERα or ERβ agonist. Involvement of ER subtypes and PI3K/Akt signaling pathway in the induced cardiovascular effects were studied using pharmacological tools of antagonists or inhibitors, gene manipulation with antisense oligonucleotide (ASON or adenovirus-mediated gene transfection. Results Similar to E2β (1 pmol, microinjection of ERβ agonist, diarylpropionitrile (DPN, 1, 2 or 5 pmol, into bilateral RVLM evoked dose-dependent hypotension and reduction in sympathetic neurogenic vasomotor tone. These vasodepressive effects of DPN (2 pmol were inhibited by ERβ antagonist, R,R-tetrahydrochrysene (50 pmol, ASON against ERβ mRNA (250 pmol, PI3K inhibitor LY294002 (5 pmol, or Akt inhibitor (250 pmol, but not by ERα inhibitor, methyl-piperidino-pyrazole (1 nmol, or transcription inhibitor, actinomycin D (5 or 10 nmol. Gene transfer by microinjection into bilateral RVLM of adenovirus encoding phosphatase and tensin homologues deleted on chromosome 10 (5 × 108 pfu reversed the vasodepressive effects of DPN. Conclusions Our results indicate that vasodepressive effects following activation of ERβ in RVLM are mediated by nongenomic activation of PI3K/Akt signaling pathway. This study provides new insight in the

  10. BLOCKADE OF ROSTRAL VENTROLATERAL MEDULLA (RVLM BOMBESIN RECEPTOR TYPE 1 DECREASES BLOOD PRESSURE AND SYMPATHETIC ACTIVITY IN ANESTHETIZED SPONTANEOUSLY HYPERTENSIVE RATS

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    Izabella Silva De Jesus Pinto

    2016-06-01

    Full Text Available IIntrathecal injection of bombesin (BBS promoted hypertensive and sympathoexcitatory effects in normotensive (NT rats. However, the involvement of rostral ventrolateral medulla (RVLM in these responses is still unclear. In the present study, we investigated: (1 the effects of BBS injected bilaterally into RVLM on cardiorespiratory and sympathetic activity in NT and spontaneously hypertensive rats (SHR; (2 the contribution of RVLM bombesin type 1 receptors (BB1 to the maintenance of hypertension in SHR. Urethane-anesthetized rats (1.2 g · kg−1, i.v. were instrumented to record mean arterial pressure (MAP, diaphragm (DIA motor and renal sympathetic nerve activity (RSNA. In NT rats and SHR, BBS (0.3 mM nanoinjected into RVLM increased MAP (33.9 ± 6.6 mmHg and 37.1 ± 4.5 mmHg, respectively; p < 0.05 and RSNA (97.8 ± 12.9 % and 84.5 ± 18.1 %, respectively; p < 0.05. In SHR, BBS also increased DIA burst amplitude (115.3 ± 22.7 %; p < 0.05. BB1 receptors antagonist (BIM-23127; 3 mM reduced MAP (-19.9 ± 4.4 mmHg; p < 0.05 and RSNA (-17.7 ± 3.8 %; p < 0.05 in SHR, but not in NT rats (-2.5 ± 2.8 mmHg; -2.7 ± 5.6 %, respectively. These results show that BBS can evoke sympathoexcitatory and pressor responses by activating RVLM BB1 receptors. This pathway might be involved in the maintenance of high levels of arterial blood pressure in SHR.

  11. Differential engagements of glutamate and GABA receptors in cardiovascular actions of endogenous nNOS or iNOS at rostral ventrolateral medulla of rats

    Science.gov (United States)

    Chan, Samuel H H; Wang, Ling-Lin; Chan, Julie Y H

    2003-01-01

    We evaluated in Sprague–Dawley rats anaesthetized with propofol the engagement of soluble guanylyl cyclase (sGC)/cGMP cascade, glutamatergic and GABAergic neurotransmission in the cardiovascular actions of endogenous nitric oxide (NO) at the rostral ventrolateral medulla (RVLM). Microinjection bilaterally into the RVLM of a selective iNOS inhibitor, S-methylisothiourea (SMT, 250 pmoles), or a selective nNOS inhibitor, 7-nitroindazole (7-NI, 5 pmoles), induced respectively an enhancement or a reduction in systemic arterial pressure, heart rate and power density of the vasomotor components in the spectrum of arterial blood pressure signals, our experimental index for sympathetic neurogenic vasomotor tone. The cardiovascular actions of SMT or 7-NI in the RVLM were significantly antagonized by co-administration into the RVLM of the sGC inhibitor, 1H-[1,2,4]Oxadiazole[4,3-α]quinoxalin-1-one (ODQ, 250 or 500 pmoles). The cardiovascular excitatory effects after blockade of endogenous iNOS activity were significantly attenuated when N-methyl-D-aspartate (NMDA) receptor antagonist, dizocilpine (20 or 50 pmoles), or non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (250 or 500 pmoles), was co-microinjected bilaterally into the RVLM. On the other hand, the cardiovascular depressive responses to blockade of endogenous nNOS activity were significantly antagonized on co-administration of GABAA receptor antagonist, bicuculline methiodine (5 or 10 pmoles), but not GABAB receptor antagonist, 2-hydroxy saclofen (50 or 100 pmoles). We conclude that the cardiovascular actions of endogenous NO in the RVLM engage the sGC/cGMP pathway. In addition, whereas NO derived from nNOS induced sympathoexcitation via both NMDA and non-NMDA receptors in the RVLM, NO generated by iNOS elicited sympathoinhibition via GABAA receptors. PMID:12598412

  12. Inhibition of p38 mitogen-activated protein kinase activation in the rostral anterior cingulate cortex attenuates pain-related negative emotion in rats.

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    Cao, Hong; Zang, Kai-Kai; Han, Mei; Zhao, Zhi-Qi; Wu, Gen-Cheng; Zhang, Yu-Qiu

    2014-08-01

    The emotional components of pain are far less studied than the sensory components. Previous studies have indicated that the rostral anterior cingulate cortex (rACC) is implicated in the affective response to noxious stimuli. Activation of p38 mitogen-activated protein kinase (MAPK) in the spinal cord has been documented to play an important role in diverse kinds of pathological pain states. We used formalin-induced conditioned place aversion (F-CPA) in rats, an animal model believed to reflect the emotional response to pain, to investigate the involvement of p38 MAPK in the rACC after the induction of affective pain. Intraplantar formalin injection produced a significant activation of p38 MAPK, as well as mitogen-activated kinase kinase (MKK) 3 and MKK6, its upstream activators, in the bilateral rACC. p38 MAPK was elevated in both NeuN-positive neurons and Iba1-positive microglia in the rACC, but not GFAP-positive cells. Blocking p38 MAPK activation in the bilateral rACC using its specific inhibitor SB203580 or SB239063 dose-dependently suppressed the formation of F-CPA. Inhibiting p38 MAPK activation did not affect formalin-induced two-phase spontaneous nociceptive response and low intensity electric foot-shock induced CPA. The present study demonstrated that p38 MAPK signaling pathway in the rACC contributes to pain-related negative emotion. Thus, a new pharmacological strategy targeted at the p38 MAPK cascade may be useful in treating pain-related emotional disorders.

  13. The dorsomedial hypothalamus mediates stress-induced hyperalgesia and is the source of the pronociceptive peptide cholecystokinin in the rostral ventromedial medulla.

    Science.gov (United States)

    Wagner, K M; Roeder, Z; Desrochers, K; Buhler, A V; Heinricher, M M; Cleary, D R

    2013-05-15

    While intense or highly arousing stressors have long been known to suppress pain, relatively mild or chronic stress can enhance pain. The mechanisms underlying stress-induced hyperalgesia (SIH) are only now being defined. The physiological and neuroendocrine effects of mild stress are mediated by the dorsomedial hypothalamus (DMH), which has documented connections with the rostral ventromedial medulla (RVM), a brainstem region capable of facilitating nociception. We hypothesized that stress engages both the DMH and the RVM to produce hyperalgesia. Direct pharmacological activation of the DMH increased sensitivity to mechanical stimulation in awake animals, confirming that the DMH can mediate behavioral hyperalgesia. A behavioral model of mild stress also produced mechanical hyperalgesia, which was blocked by inactivation of either the DMH or the RVM. The neuropeptide cholecystokinin (CCK) acts in the RVM to enhance nociception and is abundant in the DMH. Using a retrograde tracer and immunohistochemical labeling, we determined that CCK-expressing neurons in the DMH are the only significant supraspinal source of CCK in the RVM. However, not all neurons projecting from the DMH to the RVM contained CCK, and microinjection of the CCK2 receptor antagonist YM022 in the RVM did not interfere with SIH, suggesting that transmitters in addition to CCK play a significant role in this connection during acute stress. While the RVM has a well-established role in facilitation of nociception, the DMH, with its well-documented role in stress, may also be engaged in a number of chronic or abnormal pain states. Taken as a whole, these findings establish an anatomical and functional connection between the DMH and RVM by which stress can facilitate pain.

  14. Therapeutic subthalamic nucleus deep brain stimulation reverses cortico-thalamic coupling during voluntary movements in Parkinson's disease.

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    Josh Kahan

    Full Text Available Deep brain stimulation of the subthalamic nucleus (STN DBS has become an accepted treatment for patients experiencing the motor complications of Parkinson's disease (PD. While its successes are becoming increasingly apparent, the mechanisms underlying its action remain unclear. Multiple studies using radiotracer-based imaging have investigated DBS-induced regional changes in neural activity. However, little is known about the effect of DBS on connectivity within neural networks; in other words, whether DBS impacts upon functional integration of specialized regions of cortex. In this work, we report the first findings of fMRI in 10 subjects with PD and fully implanted DBS hardware receiving efficacious stimulation. Despite the technical demands associated with the safe acquisition of fMRI data from patients with implanted hardware, robust activation changes were identified in the insula cortex and thalamus in response to therapeutic STN DBS. We then quantified the neuromodulatory effects of DBS and compared sixteen dynamic causal models of effective connectivity between the two identified nodes. Using Bayesian model comparison, we found unequivocal evidence for the modulation of extrinsic (between region, i.e. cortico-thalamic and thalamo-cortical connections. Using Bayesian model parameter averaging we found that during voluntary movements, DBS reversed the effective connectivity between regions of the cortex and thalamus. This casts the therapeutic effects of DBS in a fundamentally new light, emphasising a role in changing distributed cortico-subcortical interactions. We conclude that STN DBS does impact upon the effective connectivity between the cortex and thalamus by changing their sensitivities to extrinsic afferents. Furthermore, we confirm that fMRI is both feasible and is tolerated well by these patients provided strict safety measures are adhered to.

  15. Consistent phosphenes generated by electrical microstimulation of the visual thalamus. An experimental approach for thalamic visual neuroprostheses

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    Fivos ePanetsos

    2011-07-01

    Full Text Available Most work on visual prostheses has centred on developing retinal or cortical devices. However, when retinal implants are not feasible, neuroprostheses could be implanted in the lateral geniculate nucleus of the thalamus (LGN, the intermediate relay station of visual information from the retina to the visual cortex (V1. The objective of the present study was to determine the types of artificial stimuli that when delivered to the visual thalamus can generate reliable responses of the cortical neurons similar to those obtained when the eye perceives a visual image. Visual stimuli {Si} were presented to one eye of an experimental animal and both, the thalamic {RThi} and cortical responses {RV1i} to such stimuli were recorded. Electrical patterns {RThi*} resembling {RThi} were then injected into the visual thalamus to obtain cortical responses {RV1i*} similar to {RV1i}. Visually- and electrically-generated V1 responses were compared.Results: During the course of this work we: (i characterised the response of V1 neurons to visual stimuli according to response magnitude, duration, spiking rate and the distribution of interspike intervals; (ii experimentally tested the dependence of V1 responses on stimulation parameters such as intensity, frequency, duration, etc. and determined the ranges of these parameters generating the desired cortical activity; (iii identified similarities between responses of V1 useful to compare the naturally and artificially generated neuronal activity of V1; and (iv by modifying the stimulation parameters, we generated artificial V1 responses similar to those elicited by visual stimuli.Generation of predictable and consistent phosphenes by means of artificial stimulation of the LGN is important for the feasibility of visual prostheses. Here we proved that electrical stimuli to the LGN can generate V1 neural responses that resemble those elicited by natural visual stimuli.

  16. Bilateral central pain sensitization in rats following a unilateral thalamic lesion may be treated with high doses of ketamine

    Science.gov (United States)

    2013-01-01

    Background Central post-stroke pain is a neuropathic pain condition caused by a vascular lesion, of either ischemic or hemorrhagic origin, in the central nervous system and more precisely involving the spinothalamocortical pathway responsible for the transmission of painful sensations. Few animal models have been developed to study this problem. The objectives of this study were to evaluate different modalities of pain in a central neuropathic pain rat model and to assess the effects of ketamine administered at different doses. Animals were evaluated on the rotarod, Hargreaves, Von Frey and acetone tests. A very small hemorrhage was created by injecting a collagenase solution in the right ventral posterolateral thalamic nucleus. Following the establishment of the neuropathy, ketamine was evaluated as a therapeutic drug for this condition. Results Histopathological observations showed a well localized lesion with neuronal necrosis and astrocytosis following the collagenase injection that was localized within the VPL. No significant change in motor coordination was observed following surgery in either the saline or collagensae groups. In the collagenase group, a significant decrease in mechanical allodynia threshold was observed. A sporadic and transient cold allodynia was also noted. No thermal hyperalgesia was seen following the collagenase injection. Ketamine was then tested as a potential therapeutic drug. A significant decrease in motor coordination was seen only following the administration of 25 mg/kg of ketamine in both groups. An alleviation of mechanical allodynia was achieved only with the high ketamine dose. The minimal effective ketamine serum concentration (150 ng/mL) was only achieved in animals that received 25 mg/kg. Conclusions An intrathalamic hemorrhage induced a bilateral mechanical allodynia in rats. Cold hyperalgesia was observed in 60% of these animals. Mechanical allodynia was alleviated with high doses of ketamine which corresponded

  17. Role of the thalamic nucleus reuniens in mediating interactions between the hippocampus and medial prefrontal cortex during spatial working memory

    Directory of Open Access Journals (Sweden)

    Amy L Griffin

    2015-03-01

    Full Text Available Despite decades of research, the neural mechanisms of spatial working memory remain poorly understood. Although the dorsal hippocampus is known to be critical for memory-guided behavior, experimental evidence suggests that spatial working memory depends not only on the hippocampus itself, but also on the circuit comprised of the hippocampus and the medial prefrontal cortex (mPFC. Disruption of hippocampal-mPFC interactions may result in failed transfer of spatial and contextual information processed by the hippocampus to the circuitry in mPFC responsible for decision making and goal-directed behavior. Oscillatory synchrony between the hippocampus and mPFC has been shown to increase in tasks with high spatial working memory demand. However, the mechanisms and circuitry supporting hippocampal-mPFC interactions during these tasks is unknown. The midline thalamic nucleus reuniens (RE is reciprocally connected to both the hippocampus and the mPFC and has been shown to be critical for a variety of working memory tasks. Therefore, it is likely that hippocampal-mPFC oscillatory synchrony is modulated by RE activity. This article will review the anatomical connections between the hippocampus, mPFC and RE along with the behavioral studies that have investigated the effects of RE disruption on working memory task performance. The article will conclude with suggestions for future directions aimed at identifying the specific role of the RE in regulating functional interactions between the hippocampus and the PFC and investigating the degree to which these interactions contribute to spatial working memory.

  18. Thalamic volume deficit contributes to procedural and explicit memory impairment in HIV infection with primary alcoholism comorbidity.

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    Fama, Rosemary; Rosenbloom, Margaret J; Sassoon, Stephanie A; Rohlfing, Torsten; Pfefferbaum, Adolf; Sullivan, Edith V

    2014-12-01

    Component cognitive and motor processes contributing to diminished visuomotor procedural learning in HIV infection with comorbid chronic alcoholism (HIV+ALC) include problems with attention and explicit memory processes. The neural correlates associated with this constellation of cognitive and motor processes in HIV infection and alcoholism have yet to be delineated. Frontostriatal regions are affected in HIV infection, frontothalamocerebellar regions are affected in chronic alcoholism, and frontolimbic regions are likely affected in both; all three of these systems have the potential of contributing to both visuomotor procedural learning and explicit memory processes. Here, we examined the neural correlates of implicit memory, explicit memory, attention, and motor tests in 26 HIV+ALC (5 with comorbidity for nonalcohol drug abuse/dependence) and 19 age-range matched healthy control men. Parcellated brain volumes, including cortical, subcortical, and allocortical regions, as well as cortical sulci and ventricles, were derived using the SRI24 brain atlas. Results indicated that smaller thalamic volumes were associated with poorer performance on tests of explicit (immediate and delayed) and implicit (visuomotor procedural) memory in HIV+ALC. By contrast, smaller hippocampal volumes were associated with lower scores on explicit, but not implicit memory. Multiple regression analyses revealed that volumes of both the thalamus and the hippocampus were each unique independent predictors of explicit memory scores. This study provides evidence of a dissociation between implicit and explicit memory tasks in HIV+ALC, with selective relationships observed between hippocampal volume and explicit but not implicit memory, and highlights the relevance of the thalamus to mnemonic processes.

  19. Post-training Inactivation of the Anterior Thalamic Nuclei Impairs Spatial Performance on the Radial Arm Maze

    Science.gov (United States)

    Harvey, Ryan E.; Thompson, Shannon M.; Sanchez, Lilliana M.; Yoder, Ryan M.; Clark, Benjamin J.

    2017-01-01

    The limbic thalamus, specifically the anterior thalamic nuclei (ATN), contains brain signals including that of head direction cells, which fire as a function of an animal's directional orientation in an environment. Recent work has suggested that this directional orientation information stemming from the ATN contributes to the generation of hippocampal and parahippocampal spatial representations, and may contribute to the establishment of unique spatial representations in radially oriented tasks such as the radial arm maze. While previous studies have shown that ATN lesions can impair spatial working memory performance in the radial maze, little work has been done to investigate spatial reference memory in a discrimination task variant. Further, while previous studies have shown that ATN lesions can impair performance in the radial maze, these studies produced the ATN lesions prior to training. It is therefore unclear whether the ATN lesions disrupted acquisition or retention of radial maze performance. Here, we tested the role of ATN signaling in a previously learned spatial discrimination task on a radial arm maze. Rats were first trained to asymptotic levels in a task in which two maze arms were consistently baited across training. After 24 h, animals received muscimol inactivation of the ATN before a 4 trial probe test. We report impairments in post-inactivation trials, suggesting that signals from the ATN modulate the use of a previously acquired spatial discrimination in the radial-arm maze. The results are discussed in relation to the thalamo-cortical limbic circuits involved in spatial information processing, with an emphasis on the head direction signal. PMID:28321178

  20. A Thalamic-Fronto-Parietal Structural Covariance Network Emerging in the Course of Recovery from Hand Paresis after Ischemic Stroke.

    Science.gov (United States)

    Abela, Eugenio; Missimer, John H; Federspiel, Andrea; Seiler, Andrea; Hess, Christian Walter; Sturzenegger, Matthias; Wiest, Roland; Weder, Bruno J

    2015-01-01

    To describe structural covariance networks of gray matter volume (GMV) change in 28 patients with first-ever stroke to the primary sensorimotor cortices, and to investigate their relationship to hand function recovery and local GMV change. Tensor-based morphometry maps derived from high-resolution structural images were subject to principal component analyses to identify the networks. We calculated correlations between network expression and local GMV change, sensorimotor hand function and lesion volume. To verify which of the structural covariance networks of GMV change have a significant relationship to hand function, we performed an additional multivariate regression approach. Expression of the second network, explaining 9.1% of variance, correlated with GMV increase in the medio-dorsal (md) thalamus and hand motor skill. Patients with positive expression coefficients were distinguished by significantly higher GMV increase of this structure during stroke recovery. Significant nodes of this network were located in md thalamus, dorsolateral prefrontal cortex, and higher order sensorimotor cortices. Parameter of hand function had a unique relationship to the network and depended on an interaction between network expression and lesion volume. Inversely, network expression is limited in patients with large lesion volumes. Chronic phase of sensorimotor cortical stroke has been characterized by a large scale co-varying structural network in the ipsilesional hemisphere associated specifically with sensorimotor hand skill. Its expression is related to GMV increase of md thalamus, one constituent of the network, and correlated with the cortico-striato-thalamic loop involved in control of motor execution and higher order sensorimotor cortices. A close relation between expression of this network with degree of recovery might indicate reduced compensatory resources in the impaired subgroup.

  1. Early Idiopathic Normal Pressure Hydrocephalus Patients With Neuropsychological Impairment Are Associated With Increased Fractional Anisotropy in the Anterior Thalamic Nucleus.

    Science.gov (United States)

    Chen, Yung-Chieh; Chiang, Shih-Wei; Chi, Chia-Hsing; Liou, Michelle; Kuo, Duen-Pang; Kao, Hung-Wen; Chung, Hsiao-Wen; Ma, Hsin I; Peng, Giia-Sheun; Wu, Yu-Te; Chen, Cheng-Yu

    2016-05-01

    In this study, we aimed to investigate the reactive changes in diffusion tensor imaging (DTI)-derived diffusion metrics of the anterior thalamic nucleus (AN), a relaying center for the Papez circuit, in early idiopathic normal pressure hydrocephalus (iNPH) patients with memory impairment, as well as its correlation with the patients' neuropsychological performances. In total, 28 probable iNPH patients with symptom onset within 1 year and 17 control subjects were prospectively recruited between 2010 and 2013 for this institutional review board-approved study. Imaging studies including DTI and a neuropsychological assessment battery were performed in all subjects. Diffusion metrics were measured from the region of the AN using tract-deterministic seeding method by reconstructing the mammillo-thalamo-cingulate connections within the Papez circuit. Differences in diffusion metrics and memory assessment scores between the patient and control group were examined via the Mann-Whitney U test. Spearman correlation analyses were performed to examine associations between diffusion metrics of AN and neuropsychological tests within the patient group. We discovered that early iNPH patients exhibited marked elevations in fractional anisotropy, pure diffusion anisotropy, and axial diffusivity (all P memory (all P metrics and neuropsychological test scores in the patient group, whereas ranked scatter plots clearly demonstrated a dichotic sample distribution between patient and control samples. In summary, our study highlighted the potential compensatory role of the AN by increasing thalamocortical connectivity within the Papez circuit because memory function declines in early iNPH when early shunt treatment may potentially reverse the memory deficits.

  2. A thalamic-fronto-parietal structural covariance network emerging in the course of recovery from hand paresis after ischemic stroke

    Directory of Open Access Journals (Sweden)

    Eugenio eAbela

    2015-10-01

    Full Text Available Aim: To describe structural covariance networks of grey matter volume (GMV change in 28 patients with first-ever stroke to the primary sensorimotor cortices, and to investigate their relationship to hand function recovery and local GMV change.Methods: Tensor based morphometry maps derived from high resolution structural images were subject to principal component analyses to identify the networks. We calculated correlations between network expression and local GMV change, sensorimotor hand function and lesion volume. To verify which of the structural covariance networks of GMV change have a significant relationship to hand function we performed an additional multivariate regression approach.Results: Expression of the second network, explaining 9.1% of variance, correlated with GMV increase in the medio-dorsal (md thalamus and hand motor skill. Patients with positive expression coefficients were distinguished by significantly higher GMV-increase of this structure during stroke recovery. Significant nodes of this network were located in md thalamus, dorsolateral prefrontal cortex and higher order sensorimotor cortices. Parameter of hand function had a unique relationship to the network and depended on an interaction between network expression and lesion volume. Inversely network expression is limited in patients with large lesion volumes.Conclusions: Chronic phase of sensorimotor cortical stroke has been characterized by a large scale covarying structural network in the ipsilesional hemisphere associated specifically with sensorimotor hand skill. Its expression is related to GMV-increase of md thalamus, one constituent of the network, and correlated with the cortico-striato-thalamic loop involved in control of motor execution and higher order sensorimotor cortices. A close relation between expression of this network with degree of recovery might indicate reduced compensatory resources in the impaired subgroup.

  3. Thalamic deep brain stimulation for the treatment of tremor due to multiple sclerosis: a prospective study of tremor and quality of life.

    Science.gov (United States)

    Berk, Caglar; Carr, Jason; Sinden, Marci; Martzke, Jeff; Honey, Christopher R

    2002-10-01

    In several studies a significant reduction in tremor after thalamic deep brain stimulation (DBS) has been reported among patients with multiple sclerosis (MS). It has not been determined if this results in an improved quality of life. In this study the authors prospectively evaluated the effects of thalamic DBS on tremor and quality of life. Videotapes of the patients' tremor were made preoperatively and 2 and 12 months postoperatively, and tremor was scored by a neurologist blinded to the treatment. Patients were tested pre- and postoperatively to measure any changes in their reported ability to perform selected activities of daily living and in their health-related quality of life. Patients were asked to complete a questionnaire about their satisfaction with the surgery. Postoperative changes were examined using paired t-tests. There were significant reductions in postural, action, and overall tremor at 2 and 12 months postoperatively. The patients' reported ability to feed themselves was significantly improved 2 months after surgery (p = 0.01). There were short-term trends toward improvement in reported dressing ability, personal hygiene, and writing. There were no significant changes in the SF-36 subscales or total score. In this cohort of patients with MS who suffered from tremor, thalamic DBS significantly improved their tremor and ability to feed themselves. Patient satisfaction with the procedure, however, was variable. Preoperative patient education about what functions might (and might not) be improved is crucial to avoid unrealistic expectations. Our results indicate that younger patients with MS tremor who had a shorter disease duration and no superimposed ataxia benefited most from this surgery.

  4. The role of the thalamic nuclei in recognition memory accompanied by recall during encoding and retrieval: an fMRI study.

    Science.gov (United States)

    Pergola, Giulio; Ranft, Alexander; Mathias, Klaus; Suchan, Boris

    2013-07-01

    The present functional imaging study aimed at investigating the contribution of the mediodorsal nucleus and the anterior nuclei of the thalamus with their related cortical networks to recognition memory and recall. Eighteen subjects performed associative picture encoding followed by a single item recognition test during the functional magnetic resonance imaging session. After scanning, subjects performed a cued recall test using the formerly recognized pictures as cues. This post-scanning test served to classify recognition trials according to subsequent recall performance. In general, single item recognition accompanied by successful recall of the associations elicited stronger activation in the mediodorsal nucleus of the thalamus and in the prefrontal cortices both during encoding and retrieval compared to recognition without recall. In contrast, the anterior nuclei of the thalamus were selectively active during the retrieval phase of recognition followed by recall. A correlational analysis showed that activation of the anterior thalamus during retrieval as assessed by measuring the percent signal changes predicted lower rates of recognition without recall. These findings show that the thalamus is critical for recognition accompanied by recall, and provide the first evidence of a functional segregation of the thalamic nuclei with respect to the memory retrieval phase. In particular, the mediodorsal thalamic-prefrontal cortical network is activated during successful encoding and retrieval of associations, which suggests a role of this system in recall and recollection. The activity of the anterior thalamic-temporal network selectively during retrieval predicts better memory performances across subjects and this confirms the paramount role of this network in recall and recollection. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Hypersexuality following bilateral thalamic infarction: case report Hiperssexualidade após infarto talâmico bilateral: relato de caso

    Directory of Open Access Journals (Sweden)

    Eduardo G. Mutarelli

    2006-03-01

    Full Text Available Hypersexuality is a rare but well recognized condition following brain injury. It has been described secondarily to dysfunction in the hypothalamus, the temporal and frontal lobes. We report a 63 year-old man that developed neuropsychological disturbances with hypersexuality as a prominent feature, disinhibition and moderate memory loss, hypersomnia and irritability after a bilateral paramedian thalamic infarction. A SPECT showed frontal hypoperfusion. We believe that these findings are expression of frontal-subcortical circuits dysfunction, particularly the orbitofrontal circuit, secondary to dorso medial thalamic infarction which probably plays a role in the determination of human sexual behavior. This case favors a thalamic modulation of frontal function.Hiperssexualidade é uma condição rara mas bem reconhecida após lesão do sistema nervoso central. A literatura medica registra casos secundários a disfunção do hipotálamo, do lobo temporal e do lobo frontal. Relatamos o caso de um homem de 63 anos de idade que desenvolveu alterações neuropsicológicas com hiperssexualidade como característica mais proeminente, desinibição, moderada perda de memória, hipersonia e irritabilidade após infarto talâmico paramediano bilateral. O SPECT evidenciou hipoperfusão frontal. Nós acreditamos que esses achados sejam expressão da disfunção de circuitos córtico-subcorticais frontais, particularmente do circuito órbito-frontal, secundária ao infarto dorsomedial do tálamo, que provavelmente desempenha papel relevante na determinação do comportamento sexual humano. Este caso favorece uma possível função moduladora do tálamo sobre os circuitos córtico-subcorticais frontais.

  6. Efficacy of unilateral deep brain stimulation of the thalamic ventralis intermedius nucleus in a patient with bipolar disorder associated with Klinefelter syndrome and essential tremor. Case report.

    Science.gov (United States)

    Telfeian, A E; Boockvar, J A; Simuni, T; Jaggi, J; Skolnick, B; Baltuch, G H

    2000-07-01

    Deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim) is a safe and effective treatment for essential tremor. Bipolar disorder and essential tremor had each been reported to occur in association with Klinefelter syndrome but the three diseases have been reported to occur together in only one patient. The genetic basis and natural history of these disorders are not completely understood and may be related rather than coincidental. The authors report on a 23-year-old man with Klinefelter syndrome (47,XXY) and bipolar disorder who was treated successfully with unilateral DBS of the thalamic Vim for essential tremor.

  7. Memory-enhancing intra-basolateral amygdala infusions of clenbuterol increase Arc and CaMKII-alpha protein expression in the rostral anterior cingulate cortex

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    Crystal M Holloway-Erickson

    2012-04-01

    Full Text Available Activation of β-adrenoceptors in the basolateral complex of the amygdala (BLA modulates memory through interactions with multiple memory systems. The cellular mechanisms for this interaction remain unresolved. Memory-modulating BLA manipulations influence expression of the protein product of the immediate early gene activity-regulated cytoskeletal-associated protein (Arc in the dorsal hippocampus, and hippocampal expression of Arc protein is critically involved in memory consolidation and long-term potentiation. The present studies examined whether this influence of the BLA is specific to the hippocampus and to Arc protein. Like the hippocampus, the rostral portion of the anterior cingulate cortex (rACC is involved in the consolidation of inhibitory avoidance (IA memory, and IA training increases Arc protein in the rACC. Because the BLA interacts with the rACC in the consolidation of IA memory, the rACC is a potential candidate for further studies of BLA modulation of synaptic plasticity. The alpha isoform of the Calcium/Calmodulin-dependent protein kinase II (CaMKIIα and the immediate early gene c-Fos are involved in long-term potentiation and memory. Both Arc and CaMKIIα proteins can be translated in isolated synapses, where the mRNA is localized, but c-Fos protein remains in the soma. To examine the influence of memory-modulating manipulations of the BLA on expression of these memory and plasticity-associated proteins in the rACC, male Sprague-Dawley rats were trained on an IA task and given intra-BLA infusions of either clenbuterol or lidocaine immediately after training. Findings suggest that noradrenergic stimulation of the BLA may modulate memory consolidation through effects on both synaptic proteins Arc and CaMKIIα, but not the somatic protein c-Fos. Furthermore, protein changes observed in the rACC following BLA manipulations suggest that the influence of the BLA on synaptic proteins is not limited to those in the dorsal

  8. Development of the rostral migratory stream and its cell apoptosis%喙端迁移流的发生及其细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    厉永强; 商超蔚; 宋敏; 高文静; 石贞玉; 邓锦波

    2012-01-01

    目的 研究生后不同日龄小鼠喙端迁移流(RMS)的发育,神经干细胞增殖和凋亡的规律. 方法 利用Caspase-8免疫荧光标记法和5'-溴脱氧尿嘧啶核苷(BrdU)法,对小鼠RMS内的神经干细胞增殖和凋亡进行研究(n=92). 结果 生后早期小鼠脑内,尤其是室管下区(SVZ)和RMS,存在大量的增殖细胞.随着小鼠年龄的增加,脑内干细胞逐渐减少,到成年,大脑皮质几乎见不到增殖的神经干细胞,但在SVZ和RMS仍可以看到许多增殖的神经干细胞.在RMS,神经干细胞增殖的同时伴随着细胞凋亡,干细胞的增殖与凋亡存在着正相关关系.结论 RMS的神经干细胞增殖与凋亡有重要的生理意义,通过细胞凋亡,RMS可以调节神经干细胞向嗅球迁移的数量,也可以调节干细胞向颗粒细胞分化.%Objective To study the development of the rostral migratory stream (RMS) of mice and the proliferation and apoptosis of neural stem cells in RMS at various postnatal ages. Methods With 5-bromodeoxyuridine (BrdU) assay and Caspase-8 immunofluorescent staining, the neuroproliferation and cell apoptosis in RMS were investigated. Results In early postnatal phase, there were many proliferative cells in the brain, especially in subventricular zone (SVZ) and RMS. With age increasing, the stem cells in the brain decreased. In the adult, the stem cells in the neocortex were hardly found except in SVZ and RMS areas. When the proliferation of stem cells was companied with apoptosis during RMS development, there was a positive correlation between cell proliferation and apoptosis. Conclusion There is an important signification for the neuroproliferation and cell apoptosis in RMS. Through cell apoptosis, the migration and differentiation of neural stem cells in RMS are regulated.

  9. Catecholaminergic neurons in synaptic connections with pre-Bötzinger complex neurons in the rostral ventrolateral medulla in normoxic and daily acute intermittent hypoxic rats.

    Science.gov (United States)

    Kang, Jun-Jun; Liang, Wei-Hua; Lam, Chun-Sing; Huang, Xiao-Feng; Yang, Shou-Jing; Wong-Riley, Margaret T T; Fung, Man-Lung; Liu, Ying-Ying

    2017-01-01

    The rostral ventrolateral medulla (RVLM) contains cardiovascular-related catecholaminergic neurons and respiratory-related pre-Bötzinger complex (pre-BötC) neurons, which are intermingled and functionally connected for coordinating cardiorespiratory activities. Daily acute intermittent hypoxia (dAIH) is known to elicit respiratory plasticity. However, it is unclear if the catecholaminergic neurons directly synapse onto pre-BötC neurons, and if the local circuitry exhibits plasticity when exposed to dAIH. The present study was aimed to determine the synaptic phenotypes between dopamine-β-hydroxylase (DβH)-immunoreactive (ir) catecholaminergic neurons and neurokinin 1 receptor (NK1R)-ir pre-BötC neurons, and the effect of dAIH on the neuronal network. Immunofluorescence histochemistry was used to reveal immunoreactivities of DβH and NK1R in the RVLM of normoxic and dAIH rats. Synaptic phenotypes were examined with double-labeling immunoelectron microscopy. We found that DβH immunoreactivity was expressed in somata and processes, some of which were in close apposition to NK1R-ir pre-BötC neurons. DβH-ir gold particles were localized to somata, dendrites, and axonal terminals. DβH-ir terminals formed asymmetric synapses, and occasionally, symmetric synapses in the pre-BötC, featuring the local circuitry. Of the synapses, 28% in normoxic and 29.6% in dAIH groups were apposed to NK1R-ir dendrites. Significant increases in DβH expression and NK1R-ir processes were found in the dAIH group. Moreover, the area and number of processes in close appositions were significantly elevated, strongly suggesting that dAIH induced plasticity with increased connections and interactions between the cardiovascular- and respiratory-related neurons in the local circuitry. In conclusion, asymmetric synapses are predominant in the crosstalk between catecholaminergic and pre-BötC neurons in the RVLM, elaborating excitatory transmission driving the coupling of cardiorespiratory

  10. mu-Opioid receptor-independent fashion of the suppression of sodium currents by mu-opioid analgesics in thalamic neurons.

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    Hashimoto, Keisuke; Amano, Taku; Kasakura, Akiko; Uhl, George R; Sora, Ichiro; Sakai, Norio; Kuzumaki, Naoko; Suzuki, Tsutomu; Narita, Minoru

    2009-03-27

    Most reports in the literature have shown that the effects of opioid analgesics are primarily mediated by mu-opioid receptor (MOR), whereas other potential targets of opioid analgesics have not been thoroughly characterized. In this study, we found that extracellular application of morphine, fentanyl or oxycodone, which are all considered to be MOR agonists, at relatively high concentrations, but not endogenous mu-opioid peptides, produced a concentration-dependent suppression of sodium currents in cultured thalamic neurons. These effects of opioids were not affected by either a MOR antagonist naloxone or a deletion of MOR gene. Among these opioids, fentanyl strongly suppressed sodium currents to the same degree as lidocaine, and both morphine and oxycodone slightly but significantly reduced sodium currents when they were present extracellularly. In contrast, the intracellular application of morphine, but not oxycodone, fentanyl or lidocaine, reduced sodium currents. These results suggest that morphine, fentanyl and oxycodone each produce the MOR-independent suppression of sodium currents by distinct mechanisms in thalamic neurons.

  11. Different cortical projections from three subdivisions of the rat lateral posterior thalamic nucleus: a single-neuron tracing study with viral vectors.

    Science.gov (United States)

    Nakamura, Hisashi; Hioki, Hiroyuki; Furuta, Takahiro; Kaneko, Takeshi

    2015-05-01

    The lateral posterior thalamic nucleus (LP) is one of the components of the extrageniculate pathway in the rat visual system, and is cytoarchitecturally divided into three subdivisions--lateral (LPl), rostromedial (LPrm), and caudomedial (LPcm) portions. To clarify the differences in the dendritic fields and axonal arborisations among the three subdivisions, we applied a single-neuron labeling technique with viral vectors to LP neurons. The proximal dendrites of LPl neurons were more numerous than those of LPrm and LPcm neurons, and LPrm neurons tended to have wider dendritic fields than LPl neurons. We then analysed the axonal arborisations of LP neurons by reconstructing the axon fibers in the cortex. The LPl, LPrm and LPcm were different from one another in terms of the projection targets--the main target cortical regions of LPl and LPrm neurons were the secondary and primary visual areas, whereas those of LPcm neurons were the postrhinal and temporal association areas. Furthermore, the principal target cortical layers of LPl neurons in the visual areas were middle layers, but that of LPrm neurons was layer 1. This indicates that LPl and LPrm neurons can be categorised into the core and matrix types of thalamic neurons, respectively, in the visual areas. In addition, LPl neurons formed multiple axonal clusters within the visual areas, whereas the fibers of LPrm neurons were widely and diffusely distributed. It is therefore presumed that these two types of neurons play different roles in visual information processing by dual thalamocortical innervation of the visual areas.

  12. Thinking outside a less intact box: thalamic dopamine D2 receptor densities are negatively related to psychometric creativity in healthy individuals.

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    Orjan de Manzano

    Full Text Available Several lines of evidence support that dopaminergic neurotransmission plays a role in creative thought and behavior. Here, we investigated the relationship between creative ability and dopamine D2 receptor expression in healthy individuals, with a focus on regions where aberrations in dopaminergic function have previously been associated with psychotic symptoms and a genetic liability to schizophrenia. Scores on divergent thinking tests (Inventiveness battery, Berliner Intelligenz Struktur Test were correlated with regional D2 receptor densities, as measured by Positron Emission Tomography, and the radioligands [(11C]raclopride and [(11C]FLB 457. The results show a negative correlation between divergent thinking scores and D2 density in the thalamus, also when controlling for age and general cognitive ability. Hence, the results demonstrate that the D2 receptor system, and specifically thalamic function, is important for creative performance, and may be one crucial link between creativity and psychopathology. We suggest that decreased D2 receptor densities in the thalamus lower thalamic gating thresholds, thus increasing thalamocortical information flow. In healthy individuals, who do not suffer from the detrimental effects of psychiatric disease, this may increase performance on divergent thinking tests. In combination with the cognitive functions of higher order cortical networks, this could constitute a basis for the generative and selective processes that underlie real life creativity.

  13. Thinking outside a less intact box: thalamic dopamine D2 receptor densities are negatively related to psychometric creativity in healthy individuals.

    Science.gov (United States)

    de Manzano, Orjan; Cervenka, Simon; Karabanov, Anke; Farde, Lars; Ullén, Fredrik

    2010-05-17

    Several lines of evidence support that dopaminergic neurotransmission plays a role in creative thought and behavior. Here, we investigated the relationship between creative ability and dopamine D2 receptor expression in healthy individuals, with a focus on regions where aberrations in dopaminergic function have previously been associated with psychotic symptoms and a genetic liability to schizophrenia. Scores on divergent thinking tests (Inventiveness battery, Berliner Intelligenz Struktur Test) were correlated with regional D2 receptor densities, as measured by Positron Emission Tomography, and the radioligands [(11)C]raclopride and [(11)C]FLB 457. The results show a negative correlation between divergent thinking scores and D2 density in the thalamus, also when controlling for age and general cognitive ability. Hence, the results demonstrate that the D2 receptor system, and specifically thalamic function, is important for creative performance, and may be one crucial link between creativity and psychopathology. We suggest that decreased D2 receptor densities in the thalamus lower thalamic gating thresholds, thus increasing thalamocortical information flow. In healthy individuals, who do not suffer from the detrimental effects of psychiatric disease, this may increase performance on divergent thinking tests. In combination with the cognitive functions of higher order cortical networks, this could constitute a basis for the generative and selective processes that underlie real life creativity.

  14. Combination Treatment of Low-Frequency Repetitive Transcranial Magnetic Stimulation and Intensive Occupational Therapy for Ataxic Hemiparesis due to Thalamic Hemorrhage

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    Naoki Urushidani

    2017-07-01

    Full Text Available Background: Both low-frequency repetitive transcranial magnetic stimulation (LF-rTMS and intensive occupational therapy (OT are clinically beneficial for post-stroke patients with upper-limb hemiparesis. However, the usefulness of LF-rTMS and intensive OT for ataxic hemiparesis (AH is unknown. Methods: The study subjects included 7 patients with AH. All patients had ataxia and mild hemiparesis without a sensory disturbance that was due to thalamic hemorrhage. Each patient was scheduled to receive 20-min rTMS at 1 Hz at the contralesional cerebral hemisphere followed by 120-min intensive OT, daily for 21 sessions. The primary outcome was the motor function of the affected upper limb that was evaluated by using the Fugl-Meyer Assessment (FMA. In addition, the International Cooperative Ataxia Rating Scale (ICARS score was determined to assess the severity of ataxia. Results: All patients completed the protocol without any adverse effects. The FMA score significantly increased after treatment. Notably, the ICARS score also significantly decreased. Conclusions: Our proposed combination treatment is a safe and feasible neurorehabilitative intervention for patients with AH due to thalamic hemorrhage. Our results demonstrate the possibility that rTMS in combination with intensive OT could improve motor function and alleviated ataxia in patients with AH.

  15. Netrin-1 rescues neuron loss by attenuating secondary apoptosis in ipsilateral thalamic nucleus following focal cerebral infarction in hypertensive rats.

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    Liao, S-J; Gong, Q; Chen, X-R; Ye, L-X; Ding, Q; Zeng, J-S; Yu, J

    2013-02-12

    Neurological deficit following cerebral infarction correlates with not only primary injury, but also secondary neuronal apoptosis in remote loci connected to the infarction. Netrin-1 is crucial for axonal guidance by interacting with its receptors, deleted in colorectal cancer (DCC) and uncoordinated gene 5H (UNC5H). DCC and UNC5H are also dependence receptors inducing cell apoptosis when unbound by netrin-1. The present study is to investigate the role of netrin-1 and its receptors in ipsilateral ventroposterior thalamic nucleus (VPN) injury secondary to stroke in hypertensive rats. Renovascular hypertensive Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAO). Continuous intracerebroventricular infusion of netrin-1 (600 ng/d for 7 days) or vehicle (IgG/Fc) was given 24h after MCAO. Neurological function was evaluated by postural reflex 8 and 14 days after MCAO. Then, immunoreactivity was determined in the ipsilateral VPN for NeuN, glial fibrillary acidic protein, netrin-1 and its receptors (DCC and UNC5H2), apoptosis was detected with Terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling (TUNEL) assay, and the expressions of caspase-3, netrin-1, DCC, and UNC5H2 were quantified by western blot analysis. MCAO resulted in the impaired postural reflex after 8 and 14 days, with decreased NeuN marked neurons and increased TUNEL-positive cells, as well as an up-regulation in the levels of cleaved caspase-3 and UNC5H2 protein in the ipsilateral VPN, without significant change in DCC or netrin-1 expression. By exogenous netrin-1 infusion, the number of neurons was increased in the ipsilateral VPN, and both TUNEL-positive cell number and caspase-3 protein level were reduced, while UNC5H2 expression remained unaffected, simultaneously, the impairment of postural reflex was improved. Taken together, the present study indicates that exogenous netrin-1 could rescue neuron loss by attenuating secondary apoptosis in the

  16. An autopsy-verified case of FTLD-TDP type A with upper motor neuron-predominant motor neuron disease mimicking MM2-thalamic-type sporadic Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Hayashi, Yuichi; Iwasaki, Yasushi; Takekoshi, Akira; Yoshikura, Nobuaki; Asano, Takahiko; Mimuro, Maya; Kimura, Akio; Satoh, Katsuya; Kitamoto, Tetsuyuki; Yoshida, Mari; Inuzuka, Takashi

    2016-11-01

    Here we report an autopsy-verified case of frontotemporal lobar degeneration (FTLD)-transactivation responsive region (TAR) DNA binding protein (TDP) type A with upper motor neuron-predominant motor neuron disease mimicking MM2-thalamic-type sporadic Creutzfeldt-Jakob disease (sCJD). A 69-year-old woman presented with an 11-month history of progressive dementia, irritability, insomnia, and gait disturbance without a family history of dementia or prion disease. Neurological examination revealed severe dementia, frontal signs, and exaggerated bilateral tendon reflexes. Periodic sharp-wave complexes were not observed on the electroencephalogram. Brain diffusion MRI did not reveal abnormal changes. An easy Z score (eZIS) analysis for (99m)Tc-ECD-single photon emission computed tomography ((99m)Tc-ECD-SPECT) revealed a bilateral decrease in thalamic regional cerebral blood flow (rCBF). PRNP gene analysis demonstrated methionine homozygosity at codon 129 without mutation. Cerebrospinal fluid (CSF) analysis showed normal levels of both 14-3-3 and total tau proteins. Conversely, prion protein was slowly amplified in the CSF by a real-time quaking-induced conversion assay. Her symptoms deteriorated to a state of akinetic mutism, and she died of sudden cardiac arrest, one year after symptom onset.  Despite the SPECT results supporting a clinical diagnosis of MM2-thalamic-type sCJD, a postmortem assessment revealed that this was a case of FTLD-TDP type A, and excluded prion disease. Thus, this case indicates that whereas a bilateral decreasing thalamic rCBF detected by (99m)Tc-ECD-SPECT can be useful for diagnosing MM2-thalamic-type sCJD, it is not sufficiently specific. Postmortem diagnosis remains the gold standard for the diagnosis of this condition.

  17. Thalamic posterior ventral neurons with bifurcating axons to the first and second somatosensory areas in the cat, demonstrated by the fluorescent retrograde double labeling technique.

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    Yanagihara,Mamoru

    1987-12-01

    Full Text Available The thalamic posterior ventral neurons with bifurcating axons to both the first and second somatosensory cortical areas (SI and SII in the cat were examined by the fluorescent retrograde double labeling technique. After injection of Evans blue (EB into the SI, and of 4',6-diamidino-2-phenylindol.2HCl (DAPI into the SII of the same hemisphere, EB- and DAPI-labeled cells were observed predominantly in both the posterolateral ventral and the posteromedial ventral nuclei of the thalamus. Although EB single-labeled and DAPI single-labeled cells tended to occupy separate regions within the posterior ventral nuclei, a small number of cells double-labeled with both EB and DAPI were detected in the border zone between two single-labeled cell groups. These observations indicate that some cells in the posteromedial and posterolateral ventral nuclei project both to the SI and SII by bifurcating axons.

  18. Effect of chronic electrical stimulation of the centromedian thalamic nuclei on various intractable seizure patterns: I. Clinical seizures and paroxysmal EEG activity.

    Science.gov (United States)

    Velasco, F; Velasco, M; Velasco, A L; Jiménez, F

    1993-01-01

    Twenty-three patients with various intractable seizure patterns were divided into four groups based on their most frequent seizure type and their clinical and EEG response to chronic electrical stimulation of the centromedian thalamic nuclei (ESCM): group A, generalized tonic-clonic (GTC, n = 9); group B, partial motor (Rasmussen type) (n = 3); group C, complex partial seizures (CPS, n = 5); and group D, generalized tonic seizures (Lennox-Gastaut type) (n = 6). CM were radiologically and electrophysiologically localized by means of stereotaxic landmarks and by thalamically induced scalp recruiting-like responses and desynchronization. ESCM consisted of daily 2-h stimulation sessions for 3 months. Each stimulus consisted of a 1-min train of square pulses with a 4-min interstimulus interval, alternating right and left CM. Each pulse was 1.0 ms in duration at 60/s frequency and 8-15 V (400-1,250 microA) amplitude. Voltage (V), current flow (microA) and impedance (k omega) at the electrode tips were kept constant. A significant decrease in the number of seizures per month and paroxysmal EEG waves per 10-s spochs occurred in group A patients between the baseline period (BL) and the ESCM period. These changes persisted for > 3 months after discontinuation of ESCM (poststimulation period, Post). Post was accompanied by a significant decrease in the number of paroxysmal EEG discharges. A substantial decrease in seizures and paroxysmal discharges was also observed in patients of group B. In contrast, patients of groups C and D showed no significant changes from BL to ESCM and Post periods, except for a significant decrease in the number of seizures in group D patients from BL to Post periods.

  19. Delimitação dos núcleos talâmicos pela eletrofisiologia estereotáxica Delimitation of the thalamic nuclei by stereotaxic electrophysiology

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    Nilton Luís Latuf

    1973-12-01

    Full Text Available Os limites da área destruída durante a cirurgia estereotáxica são descritos levando em consideração as complicações decorrentes de lesões determinadas erroneamente. São comentados os métodos empregados com a finalidade de controlar a delimitação do alvo, sendo descrita a técnica usada em 23 talamotomias com derivação da atividade elétrica celular dos núcleos talâmicos atravessados e a pesquisa de potenciais evocados, graças à somatotopia da representação táctil no núcleo ventral posterior. Com este método reduz-se de mais ou menos 1 mm o erro radiológico, prescisando-se o alvo terapêutico talâmico nos três planos de espaço.The limits of the area to be destroyed during the stereotaxic surgery for the treatment of tremors are described taking into account the complications due to lesions erroneously performed. The method applied is commented in order to control the accuracy of the target delimitation, describing the technique employed in 23 thalamotomies, recording the electrical activity of the thalamic nuclei acrossed and researching evoked potentials thanks to the somatotopic tactil representation in the ventral posterior nuclei. The method permits to reduce radiologic errors giving more accuracy for the delimitation of thalamic target in the three planes of space.

  20. Preferred transduction with AAV8 and AAV9 via thalamic administration in the MPS IIIB model: A comparison of four rAAV serotypes

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    J.A. Gilkes

    2016-03-01

    Full Text Available Sanfilippo syndrome type B (MPS IIIB is a lysosomal storage disease caused by a deficiency of N-acetyl-glucosaminidase (NAGLU activity. Since early therapeutic intervention is likely to yield the most efficacious results, we sought to determine the possible therapeutic utility of rAAV in early gene therapy based interventions. Currently, the application of recombinant adeno-associated virus (AAV vectors is one of the most widely used gene transfer systems, and represents a promising approach in the treatment of MPS IIIB. From a translational standpoint, a minimally invasive, yet highly efficient method of vector administration is ideal. The thalamus is thought to be the switchboard for signal relay in the central nervous system (CNS and therefore represents an attractive target. To identify an optimal AAV vector for early therapeutic intervention, and establish whether thalamic administration represents a feasible therapeutic approach, we performed a comprehensive assessment of transduction and biodistribution profiles of four green fluorescent protein (GFP bearing rAAV serotypes, -5, -8, -9 and -rh10, administered bilaterally into the thalamus. Of the four serotypes compared, AAV8 and -9 proved superior to AAV5 and -rh10 both in biodistribution and transduction efficiency profiles. Genotype differences in transduction efficiency and biodistribution patterns were also observed. Importantly, we conclude that AAV8 and to a lesser extent, AAV9 represent preferable candidates for early gene therapy based intervention in the treatment of MPS IIIB. We also highlight the feasibility of thalamic rAAV administration, and conclude that this method results in moderate rAAV biodistribution with limited treatment capacity, thus suggesting a need for alternate methods of vector delivery.

  1. T-current related effects of antiepileptic drugs and a Ca2+ channel antagonist on thalamic relay and local circuit interneurons in a rat model of absence epilepsy.

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    Broicher, Tilman; Seidenbecher, Thomas; Meuth, Patrick; Munsch, Thomas; Meuth, Sven G; Kanyshkova, Tatyana; Pape, Hans-Christian; Budde, Thomas

    2007-09-01

    Channel blocking, anti-oscillatory, and anti-epileptic effects of clinically used anti-absence substances (ethosuximide, valproate) and the T-type Ca2+ current (IT) blocker mibefradil were tested by analyzing membrane currents in acutely isolated local circuit interneurons and thalamocortical relay (TC) neurons, slow intrathalamic oscillations in brain slices, and spike and wave discharges (SWDs) occurring in vivo in Wistar Albino Glaxo rats from Rijswijk (WAG/Rij). Substance effects in vitro were compared between WAG/Rij and a non-epileptic control strain, the ACI rats. Ethosuximide (ETX) and valproate were found to block IT in acutely isolated thalamic neurons. Block of IT by therapeutically relevant ETX concentrations (0.25-0.75 mM) was stronger in WAG/Rij, although the maximal effect at saturating concentrations (>or=10 mM) was stronger in ACI. Ethosuximide delayed the onset of the low threshold Ca2+ spike (LTS) of neurons recorded in slice preparations. Mibefradil (>or=2 microM) completely blocked IT and the LTS, dampened evoked thalamic oscillations, and attenuated SWDs in vivo. Computational modeling demonstrated that the complete effect of ETX can be replicated by a sole reduction of IT. However, the necessary degree of IT reduction was not induced by therapeutically relevant ETX concentrations. A combined reduction of IT, the persistent sodium current, and the Ca2+ activated K+ current resulted in an LTS alteration resembling the experimental observations. In summary, these results support the hypothesis of IT reduction as part of the mechanism of action of anti-absence drugs and demonstrate the ability of a specific IT antagonist to attenuate rhythmic burst firing and SWDs.

  2. Surgical treatment and prognosis of thalamic cavernous mafformation%丘脑海绵状血管畸形的手术治疗及预后

    Institute of Scientific and Technical Information of China (English)

    李达; 吴震; 郝淑煜; 汤劼; 肖新如; 张力伟; 张俊廷

    2012-01-01

    目的 探讨丘脑海绵状血管畸形的手术治疗及预后.方法 对27例手术治疗的丘脑海绵状血管畸形的临床资料进行回顾性分析并随访评价.结果 27例患者共出血48次,术前KPS评分为(64.1±9.7)分.经三角区入路18例,胼胝体入路4例,其他入路5例.病灶全切26例,近全切1例.平均随访(48.7±43.2)个月,肢体力弱(53%)、肢体麻木(61%)、行走困难(25%)和视力(67%)等症状较术前改善,而言语表达无明显改善.随访KPS评分为(81.1±15.8)分,其中22例改善,5例稳定.术前KPS评分>70分(P=0.04)和女性(P=0.028)与预后显著相关.结论 手术治疗丘脑海绵状血管畸形可取得良好预后.%Objective The goal of this study was to retrospectively analyze the natural history of thalamic cavernomas and outcome after surgical resection.Method The authors retrospectively analyzed the presentation,surgery and outcomes in 27 consecutive patients who underwent microresection of thalamic cavernous malformation.Results Forty - eight times of hemorrhage occurred to 27 patients with a preoperative Karnofsky Performance Scale (KPS) of 64.1 ± 9.7.Eighteen patients underwent transtrigone lateral ventricle approach,four patients experienced interhemispheric transcallosal approach,and other approaches were applied for the remaining five patients and complete resection was achieved in 96% of patients.After a mean follow - up duration of (48.7 ± 43.2) months,symptoms of weakness,paresthesia,difficulty in walking and vision improved by 53%,61%,25% and 67%.However,verbalization did not improved obviously.The recent KPS was 81.1 ± 15.8,22 patients improved and 5 stabilized.Preoperative status and gender were the positive predictors of outcome.Conclusions Patients with thalamic cavernous malformation could obtain favorite prognosis through microsurgery.

  3. Expression and distribution of N-methyl-D-aspartate receptor 2A/B in anterior thalamic nuclei and hippocampus of rats

    Institute of Scientific and Technical Information of China (English)

    Kai Fan; Xiaokai Ma; Bin Wang

    2006-01-01

    BACKGROUND: Several immunohistochemical and in situ hybridization studies have demonstrated the localization of various N-methyl-D-aspartate receptors (NMDAR) subunits in certain brain regions of mammals. These studies indicate that NMDAR are widespread in mammal brains, especially in cerebral cortex and hippocam pus.OBJECTIVE: To validate whether or not the NMDAR 2A/B localizes in rat anterior thalamic nuclei (ATN) and hippocampus, and observe its expression and distribution characteristics. DESIGN: Controlled study.SETTING: Department of Anatomy, College of Basic Medicine, Dalian Medical University. MATERIALS: Ten adult Sprague-Dawley rats of either gender, weighing 180-250 g, of clean grade, were provided by the Experimental Animal Center, Dalian Medical University. Rabbit polyclonal antibody to NMDAR 2A/B was the product of Chemicon Company.METHODS: This experiment was carried out in the Department of Anatomy, College of Basic Medicine, Dalian Medical University from September 2005 to May 2006. The anesthetized SD rats were transcardially perfused with 100 mL phosphate buffer solution, then perfused with paraformaldehyde through ascending aorta. After 30 minutes, their brains were harvested and post-fixed in PFA at 4 ℃ overnight. Hippocampal and anterior thalamic nuclear tissues were sliced in the coronal plane at 40 μm. The sections were stained by immunohistochemical ABC method, visualized by DAB, dehydrated routinely, performed transparence and coverslipped. Expression and distribution of NMDAR 2A/B in ATN and hippocampus of rats were observed under an optical microscope.MAIN OUTCOME MEASURES: Distribution and expression of NMDAR 2A/B in ATN and hippocampus of rats, RESULTS: NMDAR 2A/B positive neurons localized in ATN, pyramidal layer of hippocampus and granular layer of dentate gyrus in a compact and orderly pattern, and immunostained intensely. NMDAR 2A/B receptor positive neurons scattered with lower intensity of immunolabeling in other regions of

  4. Usefulness of visual evaluation of the anterior thalamic radiation by diffusion tensor tractography for differentiating between Alzheimer’s disease and elderly major depressive disorder patients

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    Niida A

    2013-04-01

    Full Text Available Akira Niida,1 Richi Niida,2 Kazumasa Kuniyoshi,3 Makoto Motomura,4 Akihiko Uechi51Department of Radiology, Nanbu Hospital, Itoman City, Okinawa, Japan; 2Department of Psychiatry, Nanto Clinic, Urasoe City, Okinawa, Japan; 3Department of Neuropathic Internal Medicine, Nanbu Hospital, Itoman City, Okinawa, Japan; 4Department of Human Sciences, University of the Ryukyus, Nakagami Country, Okinawa, Japan; 5Cognitive Neuroscience Research Project, Kansai Gaidai University, Hirakata City, Osaka, JapanBackground and objective: Many surveys of neural integrity of the cerebral white matter with psychiatric diseases on diffusion tensor imaging have recently been performed, but these mainly utilize fractional anisotropy (FA and the apparent diffusion coefficient (ADC values, and the results were inconsistent and not fully applied clinically. In this study, we investigated the possibility of differentiating between Alzheimer’s disease (AD and elderly major depressive disorder (MDD patients in whom early-stage symptoms are difficult to diagnose, by visually evaluating cerebral nerve fascicles utilizing diffusion tensor tractography. We also measured and evaluated FA and ADC values at the same time.Subjects and methods: The subjects included 13 AD patients (age: 69.5 ± 5.1 years, 19 MDD patients (65.8 ± 5.7 years, and 22 healthy control (HC subjects (67.4 ± 4.8 years. Images were acquired using a 1.5T magnetic resonance imaging device and analyzed by diffusion tensor tractography analysis software.Results: Depiction of the anterior thalamic radiation (ATR tended to be poor in AD patients unlike in MDD patients and HC subjects. The FA values in the left superior longitudinal fasciculus and fornix (FX in AD patients were significantly different from those in MDD patients and HC subjects. The ADC values in the bilateral ATR and left superior and inferior longitudinal fasciculi, left inferior fronto-occipital fasciculus, and FX in AD patients were

  5. The Emotional Gatekeeper: A Computational Model of Attentional Selection and Suppression through the Pathway from the Amygdala to the Inhibitory Thalamic Reticular Nucleus.

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    Yohan J John

    2016-02-01

    Full Text Available In a complex environment that contains both opportunities and threats, it is important for an organism to flexibly direct attention based on current events and prior plans. The amygdala, the hub of the brain's emotional system, is involved in forming and signaling affective associations between stimuli and their consequences. The inhibitory thalamic reticular nucleus (TRN is a hub of the attentional system that gates thalamo-cortical signaling. In the primate brain, a recently discovered pathway from the amygdala sends robust projections to TRN. Here we used computational modeling to demonstrate how the amygdala-TRN pathway, embedded in a wider neural circuit, can mediate selective attention guided by emotions. Our Emotional Gatekeeper model demonstrates how this circuit enables focused top-down, and flexible bottom-up, allocation of attention. The model suggests that the amygdala-TRN projection can serve as a unique mechanism for emotion-guided selection of signals sent to cortex for further processing. This inhibitory selection mechanism can mediate a powerful affective 'framing' effect that may lead to biased decision-making in highly charged emotional situations. The model also supports the idea that the amygdala can serve as a relevance detection system. Further, the model demonstrates how abnormal top-down drive and dysregulated local inhibition in the amygdala and in the cortex can contribute to the attentional symptoms that accompany several neuropsychiatric disorders.

  6. The Emotional Gatekeeper: A Computational Model of Attentional Selection and Suppression through the Pathway from the Amygdala to the Inhibitory Thalamic Reticular Nucleus.

    Science.gov (United States)

    John, Yohan J; Zikopoulos, Basilis; Bullock, Daniel; Barbas, Helen

    2016-02-01

    In a complex environment that contains both opportunities and threats, it is important for an organism to flexibly direct attention based on current events and prior plans. The amygdala, the hub of the brain's emotional system, is involved in forming and signaling affective associations between stimuli and their consequences. The inhibitory thalamic reticular nucleus (TRN) is a hub of the attentional system that gates thalamo-cortical signaling. In the primate brain, a recently discovered pathway from the amygdala sends robust projections to TRN. Here we used computational modeling to demonstrate how the amygdala-TRN pathway, embedded in a wider neural circuit, can mediate selective attention guided by emotions. Our Emotional Gatekeeper model demonstrates how this circuit enables focused top-down, and flexible bottom-up, allocation of attention. The model suggests that the amygdala-TRN projection can serve as a unique mechanism for emotion-guided selection of signals sent to cortex for further processing. This inhibitory selection mechanism can mediate a powerful affective 'framing' effect that may lead to biased decision-making in highly charged emotional situations. The model also supports the idea that the amygdala can serve as a relevance detection system. Further, the model demonstrates how abnormal top-down drive and dysregulated local inhibition in the amygdala and in the cortex can contribute to the attentional symptoms that accompany several neuropsychiatric disorders.

  7. Spatial cognitive deficits in an animal model of Wernicke-Korsakoff syndrome are related to changes in thalamic VDAC protein concentrations.

    Science.gov (United States)

    Bueno, K O; de Souza Resende, L; Ribeiro, A F; Dos Santos, D M; Gonçalves, E C; Vigil, F A B; de Oliveira Silva, I F; Ferreira, L F; de Castro Pimenta, A M; Ribeiro, A M

    2015-05-21

    Proteomic profiles of the thalamus and the correlation between the rats' performance on a spatial learning task and differential protein expression were assessed in the thiamine deficiency (TD) rat model of Wernicke-Korsakoff syndrome. Two-dimensional gel-electrophoresis detected 320 spots and a significant increase or decrease in seven proteins. Four proteins were correlated to rat behavioral performance in the Morris Water Maze. One of the four proteins was identified by mass spectrometry as Voltage-Dependent Anion Channels (VDACs). The association of VDAC is evident in trials in which the rats' performance was worst, in which the VDAC protein was reduced, as confirmed by Western blot. No difference was observed on the mRNA of Vdac genes, indicating that the decreased VDAC expression may be related to a post-transcriptional process. The results show that TD neurodegeneration involves changes in thalamic proteins and suggest that VDAC protein activity might play an important role in an initial stage of the spatial learning process.

  8. Striatal dopamine D2 receptor availability predicts the thalamic and medial prefrontal responses to reward in cocaine abusers three years later

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    Asensio, S.; Goldstein, R.; Asensio, S.; Romero, M.J.; Romero, F.J.; Wong, C.T.; Alia-Klein, N.; Tomasi, D.; Wang, G.-J.; Telang, F..; Volkow, N.D.; Goldstein, R.Z.

    2010-05-01

    Low levels of dopamine (DA) D2 receptor availability at a resting baseline have been previously reported in drug addicted individuals and have been associated with reduced ventral and dorsal prefrontal metabolism. The reduction in DA D2 receptor availability along with the reduced ventral frontal metabolism is thought to underlie compromised sensitivity to nondrug reward, a core characteristic of drug addiction. We therefore hypothesized that variability in DA D2 receptor availability at baseline will covary with dynamic responses to monetary reward in addicted individuals. Striatal DA D2 receptor availability was measured with [{sup 11}C]raclopride and positron emission tomography and response to monetary reward was measured (an average of three years later) with functional magnetic resonance imaging in seven cocaine-addicted individuals. Results show that low DA D2 receptor availability in the dorsal striatum was associated with decreased thalamic response to monetary reward; while low availability in ventral striatum was associated with increased medial prefrontal (Brodmann Area 6/8/32) response to monetary reward. These preliminary results, that need to be replicated in larger sample sizes and validated with healthy controls, suggest that resting striatal DA D2 receptor availability predicts variability in functional responses to a nondrug reinforcer (money) in prefrontal cortex, implicated in behavioral monitoring, and in thalamus, implicated in conditioned responses and expectation, in cocaine-addicted individuals.

  9. Different forms of decision-making involve changes in the synaptic strength of the thalamic, hippocampal, and amygdalar afferents to the medial prefrontal cortex

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    Juan Carlos López-Ramos

    2015-01-01

    Full Text Available Decision-making and other cognitive processes are assumed to take place in the prefrontal cortex. In particular, the medial prefrontal cortex is identified in rodents by its dense connectivity with the mediodorsal thalamus, and because of its inputs from other sites, such as hippocampus and amygdala. The aim of this study was to find a putative relationship between the behavior of mice during the performance of decision-making tasks that involve penalties as a consequence of induced actions, and the strength of field postsynaptic potentials evoked in the prefrontal cortex from its thalamic, hippocampal, and amygdalar afferents. Mice were chronically implanted with stimulating electrodes in the mediodorsal thalamus, the hippocampal CA1 area, or the basolateral amygdala, and with recording electrodes in the prelimbic/infralimbic area of the prefrontal cortex. Additional stimulating electrodes aimed at evoking negative reinforcements were implanted on the trigeminal nerve. Field postsynaptic potentials evoked at the medial prefrontal cortex from the three selected projecting areas during the food/shock decision-making task decreased in amplitude with shock intensity and animals’ avoidance of the reward. Field postsynaptic potentials collected during the operant task also decreased in amplitude (but that evoked by amygdalar stimulation when lever presses were associated with a trigeminal shock. Results showed a general decrease in the strength of these potentials when animals inhibited their natural or learned appetitive behaviors, suggesting an inhibition of the prefrontal cortex in these conflicting situations.

  10. Striatal dopamine D2 receptor availability predicts the thalamic and medial prefrontal responses to reward in cocaine abusers three years later

    Science.gov (United States)

    Asensio, Samuel; Romero, Maria J.; Romero, Francisco J.; Wong, Christopher; Alia-Klein, Nelly; Tomasi, Dardo; Wang, Gene-Jack; Telang, Frank; Volkow, Nora D.; Goldstein, Rita Z.

    2009-01-01

    Low levels of dopamine (DA) D2 receptor availability at a resting baseline have been previously reported in drug addicted individuals and have been associated with reduced ventral and dorsal prefrontal metabolism. The reduction in DA D2 receptor availability along with the reduced ventral frontal metabolism is thought to underlie compromised sensitivity to non-drug reward, a core characteristic of drug addiction. We therefore hypothesized that variability in DA D2 receptor availability at baseline will covary with dynamic responses to monetary reward in addicted individuals. Striatal DA D2 receptor availability was measured with [11C]raclopride and positron emission tomography and response to monetary reward was measured (an average of 3 years later) with functional magnetic resonance imaging in seven cocaine addicted individuals. Results show that low DA D2 receptor availability in the dorsal striatum was associated with decreased thalamic response to monetary reward; while low availability in ventral striatum was associated with increased medial prefrontal (Brodmann Area 6/8/32) response to monetary reward. These preliminary results, that need to be replicated in larger sample sizes and validated with healthy controls, suggest that resting striatal DA D2 receptor availability predicts variability in functional responses to a non-drug reinforcer (money) in prefrontal cortex, implicated in behavioral monitoring, and in thalamus, implicated in conditioned responses and expectation, in cocaine addicted individuals. PMID:20034014

  11. REM sleep deprivation induces changes of down regulatory antagonist modulator (DREAM) expression in the ventrobasal thalamic nuclei of sprague-dawley rats.

    Science.gov (United States)

    Siran, Rosfaiizah; Ahmad, Asma Hayati; Abdul Aziz, Che Badariah; Ismail, Zalina

    2014-12-01

    REM sleep is a crucial component of sleep. Animal studies indicate that rapid eye movement (REM) sleep deprivation elicits changes in gene expression. Down regulatory antagonist modulator (DREAM) is a protein which downregulates other gene transcriptions by binding to the downstream response element site. The aim of this study is to examine the effect of REM sleep deprivation on DREAM expression in ventrobasal thalamic nuclei (VB) of rats. Seventy-two male Sprague-Dawley rats were divided into four major groups consisting of free-moving control rats (FMC) (n = 18), 72-h REM sleep-deprived rats (REMsd) (n = 18), 72-h REM sleep-deprived rats with 72-h sleep recovery (RG) (n = 18), and tank control rats (TC) (n = 18). REM sleep deprivation was elicited using the inverted flower pot technique. DREAM expression was examined in VB by immunohistochemical, Western blot, and quantitative real-time polymerase chain reaction (qRT-PCR) studies. The DREAM-positive neuronal cells (DPN) were decreased bilaterally in the VB of rats deprived of REM sleep as well as after sleep recovery. The nuclear DREAM extractions were increased bilaterally in animals deprived of REM sleep. The DREAM messenger RNA (mRNA) levels were decreased after sleep recovery. The results demonstrated a link between DREAM expression and REM sleep deprivation as well as sleep recovery which may indicate potential involvement of DREAM in REM sleep-induced changes in gene expression, specifically in nociceptive processing.

  12. Distonia virtual por infarto talâmico posterolateral ventral: relato de caso Virtual dystonia due to a posteroventrolateral thalamic infarct: case report

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    Ricardo De Oliveira-Souza

    1996-09-01

    dystonia not outwardly expressed through the motor system. There was severe proprioceptive loss in the same toes that harbored the cramp. MRI showed the appropriate lesion in the posteroventrolateral thalamus (VPL and wallerian degeneration of thalamo-cortical projections. SPECT showed hypoperfusion of the overlying ipsilateral parietal cortex as well as of the basal nuclei bilaterally, besides the expected image of thalamic exclusion. We hypothesize that the infarct disconnected the somatic sensory cortex (S-I from critical proprioceptive input with relative sparing of superficial sensibility. Lifting the foot deprived S-I of tonic inputs conveyed by undamaged contact-pressure pathways, a functional effect promptly reversed by placing the foot back against the ground. The case illustrates how a capricious deafferentation of S-I by a discrete VPL thalamic infarct might facilitate the emergence of autochthonous activity in the primary somesthetic cortex and give rise to a purely mental abnormal involuntary movement akin to the unimodal hallucinoses of which the syndrome of Bonnet is the best-known example. Virtual abnormal involuntary movements may be concealed more often than appreciated by complaints such as pains or cramps in patients with nervous system lesions.

  13. Dual projections of single orexin- or CART-immunoreactive, lateral hypothalamic neurons to the paraventricular thalamic nucleus and nucleus accumbens shell in the rat: Light microscopic study.

    Science.gov (United States)

    Lee, Eun Y; Lee, Hyun S

    2016-03-01

    The paraventricular thalamic nucleus (PVT) is a major relay station to the limbic forebrain areas such as the nucleus accumbens shell (AcbSh). Both PVT and AcbSh are known to receive feeding/arousal-related peptidergic fibers including orexin (ORX) and cocaine- and amphetamine-regulated transcript (CART) peptide. In the first series of experiments, we examined the peptidergic fiber distribution in the AcbSh; the density of ORX (or CART) fibers in the AcbSh was substantially lower than that in the PVT. At the light microscopic level, ORX (or CART) terminals formed close appositions to choline acetyltransferase (ChAT)-, glutamate decarboxylase (GAD)-, or enkephalin (Enk)-immunoreactive neuronal elements in the AcbSh. In the second series of experiments, we addressed the question of whether single ORX (or CART) cells in the hypothalamus provided divergent axon collaterals to the PVT and AcbSh. ORX neurons with dual projections were found in the medial, central, and lateral subdivisions of the lateral hypothalamus (LH), which amounted to an average of 1.6% of total ORX cells. CART neurons with divergent axon collaterals were observed in the LH, zona incerta, dorsal hypothalamic area, and retrochiasmatic nucleus, which represented a mean of 2.5% of total CART cells. None of arcuate CART cells sent dual projections. These data suggested that a portion of ORX (or CART) neurons in the hypothalamus, via divergent axon collaterals, might concurrently modulate the activity of PVT and AcbSh cells to affect feeding and drug-seeking behaviors.

  14. Role of the thalamic submedius nucleus histamine H1 and H 2 and opioid receptors in modulation of formalin-induced orofacial pain in rats.

    Science.gov (United States)

    Erfanparast, Amir; Tamaddonfard, Esmaeal; Taati, Mina; Dabaghi, Milad

    2015-10-01

    Histamine and opioid systems are involved in supraspinal modulation of pain. In this study, we investigated the effects of separate and combined microinjections of agonists and antagonists of histamine H1 and H2 and opioid receptors into the thalamic submedius (Sm) nucleus on the formalin-induced orofacial pain. Two guide cannulas were implanted into the right and left sides of the Sm in ketamine- and xylazine-anesthetized rats. Orofacial formalin pain was induced by subcutaneous injection of a diluted formalin solution (50 μl, 1.5%) into the vibrissa pad. Face rubbing durations were recorded at 3-min blocks for 45 min. Formalin produced a biphasic pain response (first phase: 0-3 min and second phase: 15-33 min). Separate and combined microinjections of histamine H1 and H2 receptor agonists, 2-pyridylethylamine (2-PEA) and dimaprit, respectively, and opioid receptor agonist, morphine, attenuated the second phase of pain. The analgesic effects induced by 2-PEA, dimaprit, and morphine were blocked by prior microinjections of fexofenadine (a histamine H1 receptor antagonist), famotidine (a histamine H2 receptor antagonist), and naloxone (an opioid receptor antagonist), respectively. Naloxone also prevented 2-PEA- and dimaprit-induced antinociception, and the analgesic effect induced by morphine was inhibited by fexofenadine and famotidine. These results showed the involvement of histamine H1 and H2 and opioid receptors in the Sm modulation of orofacial pain. Opioid receptor might be involved in analgesia induced by activation of histamine H1 and H2 receptors and vice versa.

  15. The yearly rate of Relative Thalamic Atrophy (yrRTA: a simple 2D/3D method for estimating deep gray matter atrophy in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Manuel eMenéndez-González

    2014-08-01

    Full Text Available Despite a strong correlation to outcome, the measurement of gray matter (GM atrophy is not being used in daily clinical practice as a prognostic factor and monitor the effect of treatments in Multiple Sclerosis (MS. This is mainly because the volumetric methods available to date are sophisticated and difficult to implement for routine use in most hospitals. In addition, the meaning of raw results from volumetric studies on regions of interest are not always easy to understand. Thus, there is a huge need of a methodology suitable to be applied in daily clinical practice in order to estimate GM atrophy in a convenient and comprehensive way. Given the thalamus is the brain structure found to be more consistently implied in MS both in terms of extent of atrophy and in terms of prognostic value, we propose a solution based in this structure. In particular, we propose to compare the extent of thalamus atrophy (TA with the extent of unspecific, global brain atrophy, represented by ventricular enlargement. We name this ratio the yearly rate of Relative Thalamic Atrophy (yrRTA. In this report we aim to describe the concept of yrRTA and the guidelines for computing it under 2D and 3D approaches and explain the rationale behind this method. We have also conducted a very short crossectional retrospective study to proof the concept of yrRTA. However, we do not seek to describe here the validity of this parameter since these researches are being conducted currently and results will be addressed in future publications.

  16. Self-sustained asynchronous irregular states and Up-Down states in thalamic, cortical and thalamocortical networks of nonlinear integrate-and-fire neurons.

    Science.gov (United States)

    Destexhe, Alain

    2009-12-01

    Randomly-connected networks of integrate-and-fire (IF) neurons are known to display asynchronous irregular (AI) activity states, which resemble the discharge activity recorded in the cerebral cortex of awake animals. However, it is not clear whether such activity states are specific to simple IF models, or if they also exist in networks where neurons are endowed with complex intrinsic properties similar to electrophysiological measurements. Here, we investigate the occurrence of AI states in networks of nonlinear IF neurons, such as the adaptive exponential IF (Brette-Gerstner-Izhikevich) model. This model can display intrinsic properties such as low-threshold spike (LTS), regular spiking (RS) or fast-spiking (FS). We successively investigate the oscillatory and AI dynamics of thalamic, cortical and thalamocortical networks using such models. AI states can be found in each case, sometimes with surprisingly small network size of the order of a few tens of neurons. We show that the presence of LTS neurons in cortex or in thalamus, explains the robust emergence of AI states for relatively small network sizes. Finally, we investigate the role of spike-frequency adaptation (SFA). In cortical networks with strong SFA in RS cells, the AI state is transient, but when SFA is reduced, AI states can be self-sustained for long times. In thalamocortical networks, AI states are found when the cortex is itself in an AI state, but with strong SFA, the thalamocortical network displays Up and Down state transitions, similar to intracellular recordings during slow-wave sleep or anesthesia. Self-sustained Up and Down states could also be generated by two-layer cortical networks with LTS cells. These models suggest that intrinsic properties such as adaptation and low-threshold bursting activity are crucial for the genesis and control of AI states in thalamocortical networks.

  17. Ca2+-dependent and Na+-dependent K+ conductances contribute to a slow AHP in thalamic paraventricular nucleus neurons: a novel target for orexin receptors.

    Science.gov (United States)

    Zhang, Li; Kolaj, Miloslav; Renaud, Leo P

    2010-10-01

    Thalamic paraventricular nucleus (PVT) neurons exhibit a postburst apamin-resistant slow afterhyperpolarization (sAHP) that is unique to midline thalamus, displays activity dependence, and is abolished in tetrodotoxin. Analysis of the underlying sI(AHP) confirmed a requirement for Ca(2+) influx with contributions from P/Q-, N-, L-, and R subtype channels, a reversal potential near E(K)(+) and a significant reduction by UCL-2077, barium or TEA, consistent with a role for K(Ca) channels. sI(AHP) was significantly reduced by activation of either the cAMP or the protein kinase C (PKC) signaling pathway. Further analysis of the sAHP revealed an activity-dependent but Ca(2+)-independent component that was reduced in high [K(+)](o) and blockable after Na(+) substitution with Li(+) or in the presence of quinidine, suggesting a role for K(Na) channels. The Ca(2+)-independent sAHP component was selectively reduced by activation of the PKC signaling pathway. The sAHP contributed to spike frequency adaptation, which was sensitive to activation of either cAMP or PKC signaling pathways and, near the peak of membrane hyperpolarization, was sufficient to cause de-inactivation of low threshold T-Type Ca(2+) channels, thus promoting burst firing. PVT neurons are densely innervated by orexin-immunoreactive fibers, and depolarized by exogenously applied orexins. We now report that orexin A significantly reduced both Ca(2+)-dependent and -independent sI(AHP), and spike frequency adaptation. Furthermore orexin A-induced sI(AHP) inhibition was mediated through activation of PKC but not PKA. Collectively, these observations suggest that K(Ca) and K(Na) channels have a role in a sAHP that contributes to spike frequency adaptation and neuronal excitability in PVT neurons and that the sAHP is a novel target for modulation by the arousal- and feeding-promoting orexin neuropeptides.

  18. Inhibitory effects of microinjection of morphine into thalamic nucleus submedius on ipsilateral paw bee venom-induced inflammatory pain in the rat

    Institute of Scientific and Technical Information of China (English)

    Jie Feng; Ning Jia; Jun-yang Wang; Xin-ai Song; Xiao-ying Li; Jing-shi Tang

    2009-01-01

    Objective To examine whether microinjectlon of morphine into the rat thaiamle nucleus submedlus (Sin) could depress the bee venom (BV)-induced nociceptive behaviours. Methods In inflammatory pain model induced by BV subcutaneous injection into rat unilateral hind paw, the inhibitory effects of morphine microinjection into thalamic nucleus suhmedius (Sin) on the spontaneous nociecptlve behavior, heat hyperalgesia and tactile ailodynia, and the influence of naioxone on the morphine effects were observed in the rat. Results A single dose of morphine (5.0 μg, 0. 5μL) applied into the Sm ipsilaterni to the BV injected paw significantly depressed the spontaneous paw flinching response. Morphine also significantly increased the heat paw withdrawal iateneies in the bilateral hind paw and the tactile paw withdrawal threshold in the ipsilnteral hind paw 2 hours after BV injection. All these depressive effects could be effectively antagonized by pre-treatment with the opiuld receptor antagonist naloxone (1.0μg, 0. 5μL) in the Sm 5rain prior to morphine administration. Naloxone alone injected to the Sm had no effect on the BV-induecd nociceptive behavior. Conclusion These results suggest that Sm is involved in opioid receptor-mediated antt-nociception in the rat with the BV-induced inflammatory pain. Together with results from previous studies, it is likely that this effect is produced by activation of the Sm-ventrolateral orbital cortex-periaqueductal gray pathway, leading to activation of the brainstem descending inhibitory system and depression of the nodceptive inputs at the spinal cord level.

  19. A mathematical and biological plausible model of decision-execution regulation in "Go/No-Go" tasks: Focusing on the fronto-striatal-thalamic pathway.

    Science.gov (United States)

    Baghdadi, Golnaz; Towhidkhah, Farzad; Rostami, Reza

    2017-07-01

    Discovering factors influencing the speed and accuracy of responses in tasks such as "Go/No-Go" is one of issues which have been raised in neurocognitive studies. Mathematical models are considered as tools to identify and to study decision making procedure from different aspects. In this paper, a mathematical model has been presented to show several factors can alter the output of decision making procedure before execution in a "Go/No-Go" task. The dynamic of this model has two stable fixed points, each of them corresponds to the "Press" and "Not-press" responses. This model that focuses on the fronto-striatal-thalamic direct and indirect pathways, receives planned decisions from frontal cortex and sends a regulated output to motor cortex for execution. The state-space analysis showed that several factors could affect the regulation procedure such as the input strength, noise value, initial condition, and the values of involved neurotransmitters. Some probable analytical reasons that may lead to changes in decision-execution regulation have been suggested as well. Bifurcation diagram analysis demonstrates that an optimal interaction between these factors can compensate the weaknesses of some others. It is predicted that abnormalities of response control in different brain disorders such as attention deficit hyperactivity disorder may be resolved by providing treatment techniques that target the regulation of the interaction. The model also suggests a possible justification to show why so many studies insist on the important role of dopamine in some brain disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Individual mediodorsal thalamic neurons project to multiple areas of the rat prefrontal cortex: A single neuron-tracing study using virus vectors.

    Science.gov (United States)

    Kuramoto, Eriko; Pan, Shixiu; Furuta, Takahiro; Tanaka, Yasuhiro R; Iwai, Haruki; Yamanaka, Atsushi; Ohno, Sachi; Kaneko, Takeshi; Goto, Tetsuya; Hioki, Hiroyuki

    2017-01-01

    The prefrontal cortex has an important role in a variety of cognitive and executive processes, and is generally defined by its reciprocal connections with the mediodorsal thalamic nucleus (MD). The rat MD is mainly subdivided into three segments, the medial (MDm), central (MDc), and lateral (MDl) divisions, on the basis of the cytoarchitecture and chemoarchitecture. The MD segments are known to topographically project to multiple prefrontal areas at the population level: the MDm mainly to the prelimbic, infralimbic, and agranular insular areas; the MDc to the orbital and agranular insular areas; and the MDl to the prelimbic and anterior cingulate areas. However, it is unknown whether individual MD neurons project to single or multiple prefrontal cortical areas. In the present study, we visualized individual MD neurons with Sindbis virus vectors, and reconstructed whole structures of MD neurons. While the main cortical projection targets of MDm, MDc, and MDl neurons were generally consistent with those of previous results, it was found that individual MD neurons sent their axon fibers to multiple prefrontal areas, and displayed various projection patterns in the target areas. Furthermore, the axons of single MD neurons were not homogeneously spread, but were rather distributed to form patchy axon arbors approximately 1 mm in diameter. The multiple-area projections and patchy axon arbors of single MD neurons might be able to coactivate cortical neuron groups in distant prefrontal areas simultaneously. Furthermore, considerable heterogeneity of the projection patterns is likely, to recruit the different sets of cortical neurons, and thus contributes to a variety of prefrontal functions. J. Comp. Neurol. 525:166-185, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Spatially distributed encoding of covert attentional shifts in human thalamus

    DEFF Research Database (Denmark)

    Hulme, Oliver J; Whiteley, Louise Emma; Shipp, Stewart

    2010-01-01

    /central-intralaminar (oculomotor thalamus), caudal intralaminar/parafascicular, suprageniculate/limitans, and medial pulvinar/lateral posterior. Hence, the cortical network generating a top-down control signal for relocating attention acts in concert with a spatially selective thalamic apparatus-the set of active nuclei mirroring...... the thalamic territory of cortical "eye-field" areas, thus supporting theories which propose the visuomotor origins of covert attentional selection.......Spatial attention modulates signal processing within visual nuclei of the thalamus--but do other nuclei govern the locus of attention in top-down mode? We examined functional MRI (fMRI) data from three subjects performing a task requiring covert attention to 1 of 16 positions in a circular array...

  2. The chicken immediate-early gene ZENK is expressed in the medio-rostral neostriatum/hyperstriatum ventrale, a brain region involved in acoustic imprinting, and is up-regulated after exposure to an auditory stimulus.

    Science.gov (United States)

    Thode, C; Bock, J; Braun, K; Darlison, M G

    2005-01-01

    The immediate-early gene zenk (an acronym for the avian orthologue of the mammalian genes zif-268, egr-1, ngfi-a and krox-24) has been extensively employed, in studies on oscine birds, as a marker of neuronal activity to reveal forebrain structures that are involved in the memory processes associated with the acquisition, perception and production of song. Audition-induced expression of this gene, in brain, has also recently been reported for the domestic chicken (Gallus gallus domesticus) and the Japanese quail (Coturnix coturnix japonica). Whilst the anatomical distribution of zenk expression was described for the quail, corresponding data for the chicken were not reported. We have, therefore, used in situ hybridisation to localise the mRNA that encodes the product of the zenk gene (which we call ZENK) within the brain of the 1-day-old chick. We demonstrate that this transcript is present in a number of forebrain structures including the medio-rostral neostriatum/hyperstriatum ventrale (MNH), a region that has been strongly implicated in auditory imprinting (which is a form of recognition memory), and Field L, the avian analog of the mammalian auditory cortex. Because of this pattern of gene expression, we have compared the level of the ZENK mRNA in chicks that have been subjected to a 30-min acoustic imprinting paradigm and in untrained controls. Our results reveal a significant increase (Pimprinting, which is an established model of juvenile learning. In addition, our results indicate that the ZENK mRNA may be used as a molecular marker for MNH, a region that is difficult to anatomically and histochemically delineate.

  3. Activity correlations between on-like and off-like cells of the rostral ventromedial medulla and simultaneously recorded wide-dynamic-range neurons of the spinal dorsal horn in rats.

    Science.gov (United States)

    Salas, Rafael; Ramirez, Karla; Vanegas, Horacio; Vazquez, Enrique

    2016-12-01

    Considerable evidence supports the notion that on- and off-cells of the rostral ventromedial medulla (RVM) facilitate and depress, respectively, spinal nociceptive transmission. This notion stems from a covariation of on- or off-cell activities and spinal nocifensive reflexes. Such covariation could theoretically be due to their independently responding to a common source, or to an RVM-derived modulation of ventral horn neurons. Here, we tested whether on- and off-cells indeed modulate spinal nociceptive neurons. In deeply anesthetized rats, unitary recordings were simultaneously made from an RVM on-like or off-like cell and a spinal nociceptive neuron that shared a receptive field (RF) at a hind paw. Action potential firing in RVM/spinal neuron pairs was highly correlated, positively for on-like cells and negatively for off-like cells, both during ongoing activity and during application of calibrated noxious pressure to the RF. Microinjection of morphine into RVM induced a correlated decrease in on-like cell/spinal neuron ongoing activity and response to noxious stimulation. RVM morphine induced changes in off-like cell activity that were not correlated with spinal neuronal activity. These results suggest that on-cells exert a positive modulation upon spinal nociceptive neurons, upstream to ventral horn circuits and plausibly at the origin of nociceptive information that eventually reaches the cerebral cortex. On-cells may in this manner contribute to inflammation- and neuropathy-induced increases in withdrawal reflexes. Most significantly, on-cell modulation of nociceptive neurons may be a key factor in clinical pain conditions such as hyperalgesia and allodynia.

  4. Activation of glycine site and GluN2B subunit of NMDA receptors is necessary for ERK/CREB signaling cascade in rostral anterior cingulate cortex in rats: Implications for affective pain

    Institute of Scientific and Technical Information of China (English)

    Hong Cao; Wen-Hua Ren; Mu-Ye Zhu; Zhi-Qi Zhao; Yu-Qiu Zhang

    2012-01-01

    Objective The rostral anterior cingulate cortex (rACC) is implicated in processing the emotional component of pain.N-methyl-D-aspartate receptors (NMDARs) are highly expressed in the rACC and mediate painrelated affect by activating a signaling pathway that involves cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and/or extracellular regulated kinase (ERK)/cAMP-response element-binding protein (CREB).The present study investigated the contributions of the NMDAR glycine site and GluN2B subunit to the activation of ERK and CREB both in vitro and in vivo in rat rACC.Methods Immunohistochemistry and Western blot analysis were used to separately assess the expression of phospho-ERK (pERK) and phospho-CREB (pCREB) in vitro and in vivo.Double immunostaining was also used to determine the colocalization of pERK and pCREB.Results Both bath application of NMDA in brain slices in vitro and intraplantar injection of formalin into the rat hindpaw in vivo induced significant up-regulation of pERK and pCREB in the rACC,which was inhibited by the NMDAR antagonist DL-2-amino-5-phospho-novaleric acid.Selective blockade of the NMDAR GluN2B subunit and the glycinebinding site,or degradation of endogenous D-serine,a co-agonist for the glycine site,significantly decreased the upregulation of pERK and pCREB expression in the rACC.Further,the activated ERK predominantly colocalized with CREB.Conclusion Either the glycine site or the GluN2B subunit of NMDARs participates in the phosphorylation of ERK and CREB induced by bath application of NMDA in brain slices or hindpaw injection of 5% formalin in rats,and these might be fundamental molecular mechanisms underlying pain affect.

  5. Preclinical evaluation of convection-enhanced delivery of liposomal doxorubicin to treat pediatric diffuse intrinsic pontine glioma and thalamic high-grade glioma.

    Science.gov (United States)

    Sewing, A Charlotte P; Lagerweij, Tonny; van Vuurden, Dannis G; Meel, Michaël H; Veringa, Susanna J E; Carcaboso, Angel M; Gaillard, Pieter J; Peter Vandertop, W; Wesseling, Pieter; Noske, David; Kaspers, Gertjan J L; Hulleman, Esther

    2017-05-01

    OBJECTIVE Pediatric high-grade gliomas (pHGGs) including diffuse intrinsic pontine gliomas (DIPGs) are primary brain tumors with high mortality and morbidity. Because of their poor brain penetrance, systemic chemotherapy regimens have failed to deliver satisfactory results; however, convection-enhanced delivery (CED) may be an alternative mode of drug delivery. Anthracyclines are potent chemotherapeutics that have been successfully delivered via CED in preclinical supratentorial glioma models. This study aims to assess the potency of anthracyclines against DIPG and pHGG cell lines in vitro and to evaluate the efficacy of CED with anthracyclines in orthotopic pontine and thalamic tumor models. METHODS The sensitivity of primary pHGG cell lines to a range of anthracyclines was tested in vitro. Preclinical CED of free doxorubicin and pegylated liposomal doxorubicin (PLD) to the brainstem and thalamus of naïve nude mice was performed. The maximum tolerated dose (MTD) was determined based on the observation of clinical symptoms, and brains were analyzed after H & E staining. Efficacy of the MTD was tested in adult glioma E98-FM-DIPG and E98-FM-thalamus models and in the HSJD-DIPG-007-Fluc primary DIPG model. RESULTS Both pHGG and DIPG cells were sensitive to anthracyclines in vitro. Doxorubicin was selected for further preclinical evaluation. Convection-enhanced delivery of the MTD of free doxorubicin and PLD in the pons was 0.02 mg/ml, and the dose tolerated in the thalamus was 10 times higher (0.2 mg/ml). Free doxorubicin or PLD via CED was ineffective against E98-FM-DIPG or HSJD-DIPG-007-Fluc in the brainstem; however, when applied in the thalamus, 0.2 mg/ml of PLD slowed down tumor growth and increased survival in a subset of animals with small tumors. CONCLUSIONS Local delivery of doxorubicin to the brainstem causes severe toxicity, even at doxorubicin concentrations that are safe in the thalamus. As a consequence, the authors could not establish a therapeutic

  6. Parvalbumin interneurons and calretinin fibers arising from the thalamic nucleus reuniens degenerate in the subiculum after kainic acid-induced seizures.

    Science.gov (United States)

    Drexel, M; Preidt, A P; Kirchmair, E; Sperk, G

    2011-08-25

    The subiculum is the major output area of the hippocampus. It is closely interconnected with the entorhinal cortex and other parahippocampal areas. In animal models of temporal lobe epilepsy (TLE) and in TLE patients it exerts increased network excitability and may crucially contribute to the propagation of limbic seizures. Using immunohistochemistry and in situ-hybridization we now investigated neuropathological changes affecting parvalbumin and calretinin containing neurons in the subiculum and other parahippocampal areas after kainic acid-induced status epilepticus. We observed prominent losses in parvalbumin containing interneurons in the subiculum and entorhinal cortex, and in the principal cell layers of the pre- and parasubiculum. Degeneration of parvalbumin-positive neurons was associated with significant precipitation of parvalbumin-immunoreactive debris 24 h after kainic acid injection. In the subiculum the superficial portion of the pyramidal cell layer was more severely affected than its deep part. In the entorhinal cortex, the deep layers were more severely affected than the superficial ones. The decrease in number of parvalbumin-positive neurons in the subiculum and entorhinal cortex correlated with the number of spontaneous seizures subsequently experienced by the rats. The loss of parvalbumin neurons thus may contribute to the development of spontaneous seizures. On the other hand, surviving parvalbumin neurons revealed markedly increased expression of parvalbumin mRNA notably in the pyramidal cell layer of the subiculum and in all layers of the entorhinal cortex. This indicates increased activity of these neurons aiming to compensate for the partial loss of this functionally important neuron population. Furthermore, calretinin-positive fibers terminating in the molecular layer of the subiculum, in sector CA1 of the hippocampus proper and in the entorhinal cortex degenerated together with their presumed perikarya in the thalamic nucleus reuniens. In

  7. Vascular Thalamic Amnesia: A Reappraisal

    Science.gov (United States)

    Carlesimo, Giovanni Augusto; Lombardi, Maria Giovanna; Caltagirone, Carlo

    2011-01-01

    In humans lacunar infarcts in the mesial and anterior regions of the thalami are frequently associated with amnesic syndromes. In this review paper, we scrutinized 41 papers published between 1983 and 2009 that provided data on a total of 83 patients with the critical ischemic lesions (i.e. 17 patients with right-sided lesions, 25 with left-sided…

  8. Sex differences in NMDA GluN1 plasticity in rostral ventrolateral medulla neurons containing corticotropin-releasing factor type 1 receptor following slow-pressor angiotensin II hypertension.

    Science.gov (United States)

    Van Kempen, T A; Dodos, M; Woods, C; Marques-Lopes, J; Justice, N J; Iadecola, C; Pickel, V M; Glass, M J; Milner, T A

    2015-10-29

    There are profound, yet incompletely understood, sex differences in the neurogenic regulation of blood pressure. Both corticotropin signaling and glutamate receptor plasticity, which differ between males and females, are known to play important roles in the neural regulation of blood pressure. However, the relationship between hypertension and glutamate plasticity in corticotropin-releasing factor (CRF)-receptive neurons in brain cardiovascular regulatory areas, including the rostral ventrolateral medulla (RVLM) and paraventricular nucleus of the hypothalamus (PVN), is not understood. In the present study, we used dual-label immuno-electron microscopy to analyze sex differences in slow-pressor angiotensin II (AngII) hypertension with respect to the subcellular distribution of the obligatory NMDA glutamate receptor subunit 1 (GluN1) subunit of the N-methyl-D-aspartate receptor (NMDAR) in the RVLM and PVN. Studies were conducted in mice expressing the enhanced green fluorescence protein (EGFP) under the control of the CRF type 1 receptor (CRF1) promoter (i.e., CRF1-EGFP reporter mice). By light microscopy, GluN1-immunoreactivity (ir) was found in CRF1-EGFP neurons of the RVLM and PVN. Moreover, in both regions tyrosine hydroxylase (TH) was found in CRF1-EGFP neurons. In response to AngII, male mice showed an elevation in blood pressure that was associated with an increase in the proportion of GluN1 on presumably functional areas of the plasma membrane (PM) in CRF1-EGFP dendritic profiles in the RVLM. In female mice, AngII was neither associated with an increase in blood pressure nor an increase in PM GluN1 in the RVLM. Unlike the RVLM, AngII-mediated hypertension had no effect on GluN1 localization in CRF1-EGFP dendrites in the PVN of either male or female mice. These studies provide an anatomical mechanism for sex-differences in the convergent modulation of RVLM catecholaminergic neurons by CRF and glutamate. Moreover, these results suggest that sexual dimorphism in

  9. 10 Degree Off-Axis Tensile Test for Intralaminar Shear Characterization of Fiber Composites.

    Science.gov (United States)

    1976-04-01

    A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the...from Mod-I/epoxy, T-300/epoxy, and S-glass/ epoxy were used in the experimental program. It was found that the 10 deg off-axis tensile test specimen is

  10. A theoretical approach for the assessment of intralaminar fracture mode and toughness of multilayered composites

    Indian Academy of Sciences (India)

    P N Dileep; R Ramesh Kumar

    2011-02-01

    Analytical evaluation of fracture toughness of a multilayered composite laminate was well-established using modified crack closure integral (MCCI) approach based on test data on the failure load. For this purpose the crack initiation direction, which is treated as a branch crack direction for the theoretical prediction, is required. The crack initiation direction in a multilayered composite laminate depends on mode of failure. In the present work, a fracture parameter $n^∗$ is introduced to predict the mode of failure in multilayered composite having a crack and is validated. Analytical relationship for the prediction of fracture toughness of multilayered composite between a base laminate and its constituent sublaminates is also arrived at. With available test data on the toughness of a set of sub-laminates, toughness of base laminate is determined and validated. The present approach is useful in evaluating the load carrying capability of composite structures with defects in the form of cracks and this information is valuable for design.

  11. Nanostitched Composites with Improved Interlaminar and Intralaminar Strengths for Advanced Airframes in Sea based Aviation

    Science.gov (United States)

    2017-04-13

    with   large  resin-­‐ rich  (pure  polymer)  regions.  This  was  not  observed  in  the  AS4/8552  UD  prepreg  to...34  MIT  Aero/Astro  SM  Thesis,  February  2016.   19.  http://www.onr.navy.mil/en/ Media -­‐Center/Fact-­‐Sheets/Airframe-­‐Structures

  12. Electrical behavior of laminated composites with intralaminar degradation: A comprehensive micro-meso homogenization procedure

    KAUST Repository

    Selvakumaran, Lakshmi

    2014-03-01

    Electrical Resistance Tomography (ERT) is a promising health monitoring technique to assess damage in laminated composites. Yet, the missing link between the various complex degradation mechanisms within the laminate and its global change in resistivity prevents ERT from being used as a quantitative technique. We propose an electrical mesomodel that can establish this link between the various microscale degradations and the resistivity changes in the measurements. The mesoscale homogenization of transverse cracks with local delamination of the ply is first described for in-plane electrical loading for both the outer and the inner plies. The mesoscale model is then extended to include the out-of-plane loading. The relationship between the mesoscale damage indicators and the degradation morphology is identified. These damage indicators are found to be intrinsic to the ply. As such, this defines the first step towards the interpretation of resistivity measurement in terms of micromechanical damage. © 2013 Elsevier Ltd.

  13. Hiperecogenicidade dos vasos talâmicos no recém-nascido prematuro Hyperechogenicity of thalamic vessels in preterm newborn infants

    Directory of Open Access Journals (Sweden)

    Natália Paczko

    2002-09-01

    Full Text Available Objetivo: o presente estudo procura avaliar as possíveis patologias que se manifestam associadas à hiperecogenicidade dos vasos talâmicos na ultra-sonografia cerebral, e observar a freqüência com que ocorrem. Métodos: a amostra foi constituída de 206 recém-nascidos prematuros, nascidos no Hospital de Clínicas de Porto Alegre, no período de julho de 1998 a maio de 1999. Todos realizaram a ultra-sonografia cerebral na primeira semana de vida. Foram incluídos no estudo aqueles prematuros que necessitaram de internação hospitalar, e que tiveram o termo de consentimento informado assinado por um dos responsáveis. Foram excluídos aqueles cuja ultra-sonografia cerebral evidenciava sangramento cerebral e/ou malformações congênitas associadas, e os que evoluíram para óbito antes da realização do exame. Resultados: a ultra-sonografia cerebral levou à identificação de 65 recém-nascidos prematuros com hiperecogenicidade dos vasos talâmicos e de 141 recém-nascidos prematuros sem. Conclusão: a forma de apresentação do tipo pélvica ao nascimento, a maior idade gestacional, o maior peso do recém-nascido ao nascimento e a classificação grande para a idade gestacional foram fatores de risco para a ocorrência de hiperecogenicidade dos vasos talâmicos, enquanto a presença de hipertensão materna durante o período de gestação tendeu a ser fator de proteção. Os recém-nascidos que apresentaram crises convulsivas durante o período de internação hospitalar tiveram risco 3,2 vezes maior de ter hiperecogenicidade dos vasos talâmicos, quando comparados aos que não apresentaram crises convulsivas.Objective: the aim of this study is to evaluate possible pathologies associated with hyperechogenicity of thalamic vessels (HETV, which are found on brain ultrasounds (BUS, as well as to observe the frequency of their occurrence. Methods: the sample was composed of 206 preterm newborn infants at Hospital de Clíncas de Porto Alegre

  14. 延髓头端腹内侧区对大鼠心脏伤害性感受的下行调控作用%Descending modulation of cardiac nociception by the rostral ventromedial medulla in rats

    Institute of Scientific and Technical Information of China (English)

    孙娜; 孔令恒; 牛利刚; 朱娟霞; 徐燕; 杜剑青

    2013-01-01

    目的:观察延髓头端腹内侧区(rostroventral medulla, RVM)对大鼠心脏伤害性感受的下行调控作用。方法通过心包插管术制作心脏-躯体运动反射(cardiosomatic motor reflex, CMR)大鼠模型,采用RVM电刺激(强度分别为25、75和100μA)及RVM电损毁的方法,以心包内可复性注入致痛剂辣椒素(capsaicin, CAP)所诱发的背斜方肌肌电(EMG)为指标评估RVM对心脏伤害性感受的下行调控作用。结果 RVM内8个刺激位点对CAP注射诱发的EMG反应产生了强度依赖性的抑制作用(F[2,21]=43.188,P=0.001);3个刺激位点产生了完全易化效应,其易化的程度与刺激强度无关(F[2,6]=0.884,P=0.461);11个刺激位点对CAP注射诱发的EMG反应产生了双向调节作用,即低强度(25μA)刺激,EMG反应明显大于基础对照(P<0.05),高强度(75/100μA)刺激,EMG反应明显低于基础对照(P<0.05);RVM实施电损毁后,EMG反应明显高于损毁前及假损毁组(P<0.05)。结论心脏受到伤害性刺激后,RVM对大鼠心脏伤害性感受具有双向调控作用,且以下行抑制性调控作用为主。%Objective To observe the descending modulation of cardiac nociception by the rostral ventromedial medulla (RVM) in rats. Methods A rat model of cardiosomatic motor reflex (CMR) was established by injecting capsaicin into the pericardial sac to induce cardiac nociception, and the electromyogram (EMG) response of the dorsal spinotrapezius muscle was studied. The RVM was electricaly stimulated (25, 75 and 100 μA) or destroyed to examine whether RVM exerted descending modulation on cardiac nociception. Results Electrical stimulation of the RVM at 8 sites produced intensity-dependent inhibition of EMG responses to noxious cardiac stimulus (F[2,21]=43.188, P=0.001). Electrical stimulation at 3 sites caused facilitated EMG responses, but the increased magnitude of the EMG was not dependent on

  15. Pro-life role for c-Jun N-terminal kinase and p38 mitogen-activated protein kinase at rostral ventrolateral medulla in experimental brain stem death

    Directory of Open Access Journals (Sweden)

    Chang Alice YW

    2012-11-01

    Full Text Available Abstract Background Based on an experimental brain stem death model, we demonstrated previously that activation of the mitogen-activated protein kinase kinase 1/2 (MEK1/2/extracellular signal-regulated kinase 1/2 (ERK1/2/mitogen-activated protein kinase signal-interacting kinase 1/2 (MNK1/2 cascade plays a pro-life role in the rostral ventrolateral medulla (RVLM, the origin of a life-and-death signal detected from systemic arterial pressure, which sequentially increases (pro-life and decreases (pro-death to reflect progressive dysfunction of central cardiovascular regulation during the advancement towards brain stem death in critically ill patients. The present study assessed the hypothesis that, in addition to ERK1/2, c-Jun NH2-terminal kinase (JNK and p38 mitogen-activated protein kinase (p38MAPK, the other two mammalian members of MAPKs that are originally identified as stress-activated protein kinases, are activated specifically by MAPK kinase 4 (MAP2K4 or MAP2K6 and play a pro-life role in RVLM during experimental brain stem death. We further delineated the participation of phosphorylating activating transcriptional factor-2 (ATF-2 and c-Jun, the classical transcription factor activated by JNK or p38MAPK, in this process. Results An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol bilaterally into RVLM of Sprague–Dawley rats was used, alongside cardiovascular, pharmacological and biochemical evaluations. Results from ELISA showed that whereas the total JNK, p38MAPK, MAP2K4 and MAP2K6 were not affected, augmented phosphorylation of JNK at Thr183 and Tyr185 and p38MAPK at Thr180 and Tyr182, accompanied by phosphorylation of their upstream activators MAP2K4 at Ser257 and Thr261 and MAP2K6 at Ser207 and Thr211 in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Moreover, the activity of transcription factors ATF-2 at Thr71 and

  16. Xingnaojing Injection in Treatment of Acute Thalamic Hemorrhage: A Clinical Observation of 52 Cases%醒脑静治疗急性丘脑出血52例临床观察

    Institute of Scientific and Technical Information of China (English)

    马慧; 张永葆

    2012-01-01

    Objective To observe the clinical efficacy of Xingnaojing Injection, a traditional Chinese medicine, in treating acute thalamic hemorrhage. Methods A total of 103 patients with acute thalamic hemorthage were randomly divided into treatment group and control group, both of which included three types (type-Ⅰ , -Ⅱ . And -Ⅲ) according to CT diagnosis. Fifty-one patients in the control group were treated with conventional therapies; additionally, 52 patients in the treatment group were treated with Xingnaojing Injection. The changes of clinical neurologic impairment scores and the recovery of conscious disturbance and increased body temperature were observed in both groups before and after treatment. Results As compared with those before treatment, the scores of clinical neurologic impairments were significantly decreased in patients with CT diagnosed type-Ⅰ and -Ⅱ in both groups after treatment (P<0. 01); and the scores in CT diagnosed type- Ⅰ and -Ⅱ patients in the treatment group were significantly lower than those in the control group (P<0. 05). Compared to those in the control group, the recovery time for conscious disturbance and increased body temperature in the treatment group was significantly shortened ( P<0. 05) ;and the average levels of increased body temperature in the treatment group were significantly lower than those in the control group (P<0. 05). Conclusion Xingnaojing Injection is an effective drug for neurologic impairments, conscious disturbance, and fever in patients with acute thalamic hemorrhage, and it can increase the cure rate and reduce the disability rate in these patients.%目的 观察醒脑静治疗急性丘脑出血的临床疗效.方法 将103例急性丘脑出血患者随机分为治疗组和对照组,两者均按CT分为3型,治疗组在对照组常规治疗基础上加用醒脑静治疗,观察两组各型丘脑出血治疗前后临床神经功能缺损程度评分变化,意识障碍转清

  17. Clinical study on combined treatment of thalamic pain using duloxetine and mecobalamin%度洛西汀联用甲钴胺治疗丘脑痛的临床观察

    Institute of Scientific and Technical Information of China (English)

    付剑亮; 姚继国; 项静燕; 蒋青青

    2009-01-01

    AIM To evaluate the safety and efficacy of different therapeutic effect of thalamic pain after stroke. METHODS Sixty-five patients with thalamic pain were randomly divided into two group: 33 patients received the combined treatment with duloxetine capsule 40 mg·d-1 and mecobalamin tablets 1 500 μg·d-1 (combined-treatment group), and 32 patients of controls received duloxetine capsule 40 mg·d-1 (control group). RESULTS There was significant difference in visual analogue scale (VAS) of the combined-treatment group before and after the treatment (7.5 ±s 1.2 vs 4.8 ± 0.9, P 0.