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Sample records for cerebral cortical circuits

  1. Mapping synaptic pathology within cerebral cortical circuits in subjects with schizophrenia

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    Robert Sweet

    2010-06-01

    Full Text Available Converging lines of evidence indicate that schizophrenia is characterized by impairments of synaptic machinery within cerebral cortical circuits. Efforts to localize these alterations in brain tissue from subjects with schizophrenia have frequently been limited to the quantification of structures that are non-selectively identified (e.g. dendritic spines labeled in Golgi preparations, axon boutons labeled with synaptophysin, or to quantification of proteins using methods unable to resolve relevant cellular compartments. Multiple label fluorescence confocal microscopy represents a means to circumvent many of these limitations, by concurrently extracting information regarding the number, morphology, and relative protein content of synaptic structures. An important adaptation required for studies of human disease is coupling this approach to stereologic methods for systematic random sampling of relevant brain regions. In this review article we consider the application of multiple label fluorescence confocal microscopy to the mapping of synaptic alterations in subjects with schizophrenia and describe the application of a novel, readily automated, iterative intensity/morphological segmentation algorithm for the extraction of information regarding synaptic structure number, size, and relative protein level from tissue sections obtained using unbiased stereological principles of sampling. In this context, we provide examples of the examination of pre- and post-synaptic structures within excitatory and inhibitory circuits of the cerebral cortex.

  2. Modeling cortical circuits.

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    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  3. Cortical hierarchy governs rat claustrocortical circuit organization.

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    White, Michael G; Cody, Patrick A; Bubser, Michael; Wang, Hui-Dong; Deutch, Ariel Y; Mathur, Brian N

    2017-04-15

    The claustrum is a telencephalic gray matter structure with various proposed functions, including sensory integration and attentional allocation. Underlying these concepts is the reciprocal connectivity of the claustrum with most, if not all, areas of the cortex. What remains to be elucidated to inform functional hypotheses further is whether a pattern exists in the strength of connectivity between a given cortical area and the claustrum. To this end, we performed a series of retrograde neuronal tract tracer injections into rat cortical areas along the cortical processing hierarchy, from primary sensory and motor to frontal cortices. We observed that the number of claustrocortical projections increased as a function of processing hierarchy; claustrum neurons projecting to primary sensory cortices were scant and restricted in distribution across the claustrum, whereas neurons projecting to the cingulate cortex were densely packed and more evenly distributed throughout the claustrum. This connectivity pattern suggests that the claustrum may preferentially subserve executive functions orchestrated by the cingulate cortex. J. Comp. Neurol. 525:1347-1362, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. Pre- and postoperative changes of regional cortical cerebral blood flow in patients with cerebral arteriovenous malformation

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    石广志; 赵继宗; 王硕; 王永刚; 陆铮

    2003-01-01

    Objective To investigate pre- and postoperative changes of regional cerebral cortical blood flow in patients with cerebral arteriovenous malformation. Method Twenty-two adult patients with arteriovenous malformation(AVM) were recruited into this study at Beijing Tiantan Hospital from September 2001 to May 2002. Eight patients had giant cerebral AVM and the other 14 had a small one. Cortical cerebral blood flow (CBF) was measured by laser Doppler flowmetry (LDF) before and after AVM resections. After surgery, the probe of LDF was implanted adjacent to the area of AVM and monitored for 24 hours.Results CBF increased significantly after the resection in all patients regardless of AVM size. In patients with small AVM, CBF returned to the baseline level within 4 hours, but in patients with giant AVM, CBF remained high even after 24 hours.Conclusions Monitoring CBF is helpful to understand pre- and postoperative changes of regional cortical CBF in patients with cerebral AVM.

  5. Somatostatin-expressing inhibitory interneurons in cortical circuits

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    Iryna Yavorska

    2016-09-01

    Full Text Available Cortical inhibitory neurons exhibit remarkable diversity in their morphology, connectivity, and synaptic properties. Here, we review the function of somatostatin-expressing (SOM inhibitory interneurons, focusing largely on sensory cortex. SOM neurons also comprise a number of subpopulations that can be distinguished by their morphology, input and output connectivity, laminar location, firing properties, and expression of molecular markers. Several of these classes of SOM neurons show unique dynamics and characteristics, such as facilitating synapses, specific axonal projections, intralaminar input, and top-down modulation, which suggest possible computational roles. SOM cells can be differentially modulated by behavioral state depending on their class, sensory system, and behavioral paradigm. The functional effects of such modulation have been studied with optogenetic manipulation of SOM cells, which produces effects on learning and memory, task performance, and the integration of cortical activity. Different classes of SOM cells participate in distinct disinhibitory circuits with different inhibitory partners and in different cortical layers. Through these disinhibitory circuits, SOM cells help encode the behavioral relevance of sensory stimuli by regulating the activity of cortical neurons based on subcortical and intracortical modulatory input. Associative learning leads to long-term changes in the strength of connectivity of SOM cells with other neurons, often influencing the strength of inhibitory input they receive. Thus despite their heterogeneity and variability across cortical areas, current evidence shows that SOM neurons perform unique neural computations, forming not only distinct molecular but also functional subclasses of cortical inhibitory interneurons.

  6. Neuroelectric Tuning of Cortical Oscillations by Apical Dendrites in Loop Circuits

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    David LaBerge

    2017-06-01

    Full Text Available Bundles of relatively long apical dendrites dominate the neurons that make up the thickness of the cerebral cortex. It is proposed that a major function of the apical dendrite is to produce sustained oscillations at a specific frequency that can serve as a common timing unit for the processing of information in circuits connected to that apical dendrite. Many layer 5 and 6 pyramidal neurons are connected to thalamic neurons in loop circuits. A model of the apical dendrites of these pyramidal neurons has been used to simulate the electric activity of the apical dendrite. The results of that simulation demonstrated that subthreshold electric pulses in these apical dendrites can be tuned to specific frequencies and also can be fine-tuned to narrow bandwidths of less than one Hertz (1 Hz. Synchronous pulse outputs from the circuit loops containing apical dendrites can tune subthreshold membrane oscillations of neurons they contact. When the pulse outputs are finely tuned, they function as a local “clock,” which enables the contacted neurons to synchronously communicate with each other. Thus, a shared tuning frequency can select neurons for membership in a circuit. Unlike layer 6 apical dendrites, layer 5 apical dendrites can produce burst firing in many of their neurons, which increases the amplitude of signals in the neurons they contact. This difference in amplitude of signals serves as basis of selecting a sub-circuit for specialized processing (e.g., sustained attention within the typically larger layer 6-based circuit. After examining the sustaining of oscillations in loop circuits and the processing of spikes in network circuits, we propose that cortical functioning can be globally viewed as two systems: a loop system and a network system. The loop system oscillations influence the network system’s timing and amplitude of pulse signals, both of which can select circuits that are momentarily dominant in cortical activity.

  7. Effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats

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    Zuoli Xia; Baoling Sun; Mingfeng Yang; Dongmei Hu; Tong Zhao; Jingzhong Niu

    2006-01-01

    BACKGROUND: It has been shown that although brain does not contain lining endothelial lymphatic vessel,it has lymphatic drain.Anterior lymphatic vessel in brain tissue plays a key role in introducing brain interstitial fluid to lymphatic system;however,the significance of lymphatic drain and the affect on cerebral edema remains unclear.OBJECTIVE: To investigate the effect of cerebral lymphatic block on cerebral morphology and cortical evoked potential in rats.DESIGN: Randomized controlled animal study.SETTING: Institute of Cerebral Microcirulation of Taishan Medical College and Department of Neurology of Affiliated Hospital.MATERIALS:A total of 63 healthy adult male Wistar rats weighing 300-350 g were selected in this study.Forty-seven rats were used for the morphological observation induced by lymphatic drain and randomly divided into three groups:general observation group(n=12),light microscopic observation group(n=21)and electronic microscopic observation group(n=14).The rats in each group were divided into cerebral lymphatic block subgroup and sham-operation control subgroup.Sixteen rats were divided into cerebral the effect of cerebral lymphatic block on cortical evoked potential,in which the animals were randomly divided into sham-operation group(n=6)and cerebral lymphatic block group(n=10).METHODS:The experiment was carried out in the Institute of Cerebral Microcirculation of Taishan Medical College from January to August 2003.Rats in cerebral lymphatic block group were anesthetized and separated bilateral superficial and deep cervical lymph nodes under sterile condition. Superior and inferior boarders of lymph nodes were ligated the inputting and outputting channels, respectively, and then lymph node was removed so as to establish cerebral lymphatic drain disorder models. Rats in sham-operation control group were not ligated the lymphatic vessel and removed lymph nodes.and other operations were as the same as those in cerebral lymphatic block group

  8. Assessing cortical cerebral microinfarcts on high resolution MR images

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    van Veluw, Susanne J.; Biessels, Geert Jan; Luijten, Peter R.; Zwanenburg, Jaco J M

    2015-01-01

    Cerebral microinfarcts are frequent findings in the post-mortem human brain, and are related to cognitive decline and dementia. Due to their small sizes it is challenging to study them on clinical MRI scans. It was recently demonstrated that cortical microinfarcts can be depicted with MRI scanners u

  9. Regional cerebral blood flow in focal cortical epilepsy

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    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were st...

  10. Towards a mathematical theory of cortical micro-circuits.

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    Dileep George

    2009-10-01

    Full Text Available The theoretical setting of hierarchical Bayesian inference is gaining acceptance as a framework for understanding cortical computation. In this paper, we describe how Bayesian belief propagation in a spatio-temporal hierarchical model, called Hierarchical Temporal Memory (HTM, can lead to a mathematical model for cortical circuits. An HTM node is abstracted using a coincidence detector and a mixture of Markov chains. Bayesian belief propagation equations for such an HTM node define a set of functional constraints for a neuronal implementation. Anatomical data provide a contrasting set of organizational constraints. The combination of these two constraints suggests a theoretically derived interpretation for many anatomical and physiological features and predicts several others. We describe the pattern recognition capabilities of HTM networks and demonstrate the application of the derived circuits for modeling the subjective contour effect. We also discuss how the theory and the circuit can be extended to explain cortical features that are not explained by the current model and describe testable predictions that can be derived from the model.

  11. Towards a mathematical theory of cortical micro-circuits.

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    George, Dileep; Hawkins, Jeff

    2009-10-01

    The theoretical setting of hierarchical Bayesian inference is gaining acceptance as a framework for understanding cortical computation. In this paper, we describe how Bayesian belief propagation in a spatio-temporal hierarchical model, called Hierarchical Temporal Memory (HTM), can lead to a mathematical model for cortical circuits. An HTM node is abstracted using a coincidence detector and a mixture of Markov chains. Bayesian belief propagation equations for such an HTM node define a set of functional constraints for a neuronal implementation. Anatomical data provide a contrasting set of organizational constraints. The combination of these two constraints suggests a theoretically derived interpretation for many anatomical and physiological features and predicts several others. We describe the pattern recognition capabilities of HTM networks and demonstrate the application of the derived circuits for modeling the subjective contour effect. We also discuss how the theory and the circuit can be extended to explain cortical features that are not explained by the current model and describe testable predictions that can be derived from the model.

  12. Cerebral venous thrombosis presenting with cerebellar ataxia and cortical blindness.

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    Ben Sassi, Samia; Mizouni, Habiba; Nabli, Fatma; Kallel, Lamia; Kefi, Mounir; Hentati, Fayçal

    2010-01-01

    Venous infarction in the cerebellum has been reported only rarely, probably because of the abundant venous collateral drainage in this region. Bilateral occipital infarction is a rare cause of visual loss in cerebral venous thrombosis. We describe a 50-year-old woman with a history of ulcerative colitis who developed acute cerebellar ataxia and cortical blindness. She had bilateral cerebellar and occipital lesions related to sigmoid venous thrombosis and achieved complete recovery with anticoagulation therapy. Cerebral venous thrombosis should be considered in cases of simultaneous cerebellar and occipital vascular lesions.

  13. Emerging roles of Axin in cerebral cortical development

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    Tao eYe

    2015-06-01

    Full Text Available Proper functioning of the cerebral cortex depends on the appropriate production and positioning of neurons, establishment of axon–dendrite polarity, and formation of proper neuronal connectivity. Deficits in any of these processes greatly impair neural functions and are associated with various human neurodevelopmental disorders including microcephaly, cortical heterotopias, and autism. The application of in vivo manipulation techniques such as in utero electroporation has resulted in significant advances in our understanding of the cellular and molecular mechanisms that underlie neural development in vivo. Axin is a scaffold protein that regulates neuronal differentiation and morphogenesis in vitro. Recent studies provide novel insights into the emerging roles of Axin in gene expression and cytoskeletal regulation during neurogenesis, neuronal polarization, and axon formation. This review summarizes current knowledge on Axin as a key molecular controller of cerebral cortical development.

  14. Extraction of the cerebral cortical boundaries from MRI for measurement of cortical thickness

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    Eskildsen, Simon F.; Uldahl, Mark; Ostergaard, Lasse R.

    2005-04-01

    Several neurodegenerative diseases, such as Alzheimer's disease, cause atrophy of the cerebral cortex. Measurements of cerebral cortical thickness and volume are used in the quantification and localization of atrophy. It is possible to measure the thickness of the cerebral cortex manually from magnetic resonance imaging, but partial volume effects, orthogonality problems, large amounts of manual labor and operator bias makes it difficult to conduct measurements on large patient populations. Automatic quantification and localization of atrophy is a highly desirable goal, as it facilitates the study of early anatomical changes and track disease progression on large populations. The first step in achieving this goal is to develop robust and accurate methods for measuring cortical thickness and volume automatically. We have developed a new method, capable of both extracting surface representations of the cortical boundaries from magnetic resonance imaging and measuring the cortical thickness. Experiments show that the developed method is robust and performs well on datasets of both healthy subjects and subjects suffering from Alzheimer's disease.

  15. Maladaptation of cortical circuits underlies fatigue and weakness in ALS.

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    Vucic, Steve; Cheah, Benjamin C; Kiernan, Matthew C

    2011-11-01

    Although fatigue is frequently reported in amyotrophic lateral sclerosis (ALS), the underlying mechanisms remain to be elucidated. Cortical excitability studies were utilized to determine the contribution of central mechanisms to development of fatigue and weakness in ALS. Threshold-tracking transcranial magnetic stimulation (TMS) studies were undertaken in 16 ALS patients and 22 normal controls using a 90-mm circular coil. TMS studies were performed at baseline, immediately after a voluntary contraction (VC) period of 120 s duration (three VC periods), and at 5, 10 and 20 min after last VC. At baseline, there was a significant reduction of short-interval intracortical inhibition (SICI) at interstimulus interval of 1 ms (ALS 2.3 ± 2.3%; controls 9.5 ± 2.5%, p < 0.01) and 3 ms (ALS5.1 ± 3.4%; controls 16.8 ± 1.7%, p < 0.01) in ALS patients. Although there was a significant reduction of SICI post-VC in controls at ISI 1 ms (p < 0.05) and ISI 3 ms (p < 0.05), there was no significant change in ALS patients at ISI 1 ms (p = 0.15) or 3 ms (p = 0.31). The changes in cortical excitability correlated with fatigue (R = 0.59, p < 0.05). In conclusion, maladaptation of cortical processes related to degeneration of inhibitory GABAergic intracortical circuits, is a feature of ALS that significantly correlates with development of fatigue and weakness.

  16. Cortical blindness as a rare presentation of cerebral venous thrombosis.

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    Wang, Bonnie; Moon, Seong-Jin; Olivero, William C; Wang, Huan

    2013-05-09

    Cerebral venous thrombosis (CVT) remains a diagnostic and therapeutic challenge for clinicians. Manifesting in a remarkably wide spectrum of symptoms and signs, CVT often presents in a misleading fashion-if unrecognized or misdiagnosed, it carries potentially fatal consequences. Visual loss is quite rare as the initial presentation of CVT and is typically a finding more frequent in chronic cases with associated papilledema on funduscopy Ferro, Lopes, Rosas and Fontes (Delay in Hospital Admission of Patients with Cerebral Vein and Dural Sinus Thrombosis. Cerebrovasc Dis 2005;19: :152-6). We report a rare case of acute cortical blindness as the initial presentation of CVT in an 18-year-old female patient and review the current literature.

  17. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were....... This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal...

  18. Response of Quiescent Cerebral Cortical Astrocytes to Nanofibrillar Scaffold Properties

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    Ayres, Virginia; Mujdat Tiryaki, Volkan; Xie, Kan; Ahmed, Ijaz; Shreiber, David I.

    2013-03-01

    We present results of an investigation to examine the hypothesis that the extracellular environment can trigger specific signaling cascades with morphological consequences. Differences in the morphological responses of quiescent cerebral cortical astrocytes cultured on the nanofibrillar matrices versus poly-L-lysine functionalized glass and Aclar, and unfunctionalized Aclar surfaces were demonstrated using atomic force microscopy (AFM) and phalloidin staining of F-actin. The differences and similarities of the morphological responses were consistent with differences and similarities of the surface polarity and surface roughness of the four surfaces investigated in this work, characterized using contact angle and AFM measurements. The three-dimensional capability of AFM was also used to identify differences in cell spreading. An initial quantitative immunolabeling study further identified significant differences in the activation of the Rho GTPases: Cdc42, Rac1, and RhoA, which are upstream regulators of the observed morphological responses: filopodia, lamellipodia, and stress fiber formation. The results support the hypothesis that the extracellular environment can trigger preferential activation of members of the Rho GTPase family with demonstrable morphological consequences for cerebral cortical astrocytes. The support of NSF PHY-095776 is acknowledged.

  19. Electrophysiological Data and the Biophysical Modelling of Local Cortical Circuits

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    Dimitris Pinotsis

    2014-03-01

    Full Text Available This paper shows how recordings of gamma oscillations – under different experimental conditions or from different subjects – can be combined with a class of population models called neural fields and dynamic causal modeling (DCM to distinguish among alternative hypotheses regarding cortical structure and function. This approach exploits inter-subject variability and trial-specific effects associated with modulations in the peak frequency of gamma oscillations. It draws on the computational power of Bayesian model inversion, when applied to neural field models of cortical dynamics. Bayesian model comparison allows one to adjudicate among different mechanistic hypotheses about cortical excitability, synaptic kinetics and the cardinal topographic features of local cortical circuits. It also provides optimal parameter estimates that quantify neuromodulation and the spatial dispersion of axonal connections or summation of receptive fields in the visual cortex. This paper provides an overview of a family of neural field models that have been recently implemented using the DCM toolbox of the academic freeware Statistical Parametric Mapping (SPM. The SPM software is a popular platform for analyzing neuroimaging data, used by several neuroscience communities worldwide. DCM allows for a formal (Bayesian statistical analysis of cortical network connectivity, based upon realistic biophysical models of brain responses. It is this particular feature of DCM – the unique combination of generative models with optimization techniques based upon (variational Bayesian principles – that furnishes a novel way to characterize functional brain architectures. In particular, it provides answers to questions about how the brain is wired and how it responds to different experimental manipulations. For a review of the general role of neural fields in SPM the reader can consult e.g. see [1]. Neural fields have a long and illustrious history in mathematical

  20. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

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    Houdayer, Elise; Cursi, Marco; Nuara, Arturo; Zanini, Sonia; Gatti, Roberto; Comi, Giancarlo; Leocani, Letizia

    2016-01-01

    The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS). Twelve subjects (experimental group) underwent, before and after a two week-piano training: (1) hand-motor function tests: Jamar, grip and nine-hole peg tests; (2) electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD) during keyboard performance; and (3) TMS, targeting bilateral abductor pollicis brevis (APB) and abductor digiti minimi (ADM), to obtain duration and area of ipsilateral silent period (ISP) during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  1. Recombinant human erythropoietin increases cerebral cortical width index and neurogenesis following ischemic stroke

    Institute of Scientific and Technical Information of China (English)

    Zhongmin Wen; Peiji Wang

    2012-01-01

    The cerebral cortical expansion index refers to the ratio between left and right cortex width and is recognized as an indicator for cortical hyperplasia. Cerebral ischemia was established in CB-17 mice in the present study, and the mice were subsequently treated with recombinant human erythropoietin via subcutaneous injection. Results demonstrated that cerebral cortical width index significantly increased. Immunofluorescence detection showed that the number of nuclear antigen antibody/5-bromodeoxyuridine-positive cells at the infarction edge significantly increased. Correlation analysis revealed a negative correlation between neurological scores and cortical width indices in rats following ischemic stroke. These experimental findings suggested that recombinant human erythropoietin promoted cerebral cortical hyperplasia, increased cortical neurogenesis, and enhanced functional recovery following ischemic stroke.

  2. Cortical Motor Circuits after Piano Training in Adulthood: Neurophysiologic Evidence.

    Directory of Open Access Journals (Sweden)

    Elise Houdayer

    Full Text Available The neuronal mechanisms involved in brain plasticity after skilled motor learning are not completely understood. We aimed to study the short-term effects of keyboard training in music-naive subjects on the motor/premotor cortex activity and interhemispheric interactions, using electroencephalography and transcranial magnetic stimulation (TMS. Twelve subjects (experimental group underwent, before and after a two week-piano training: (1 hand-motor function tests: Jamar, grip and nine-hole peg tests; (2 electroencephalography, evaluating the mu rhythm task-related desynchronization (TRD during keyboard performance; and (3 TMS, targeting bilateral abductor pollicis brevis (APB and abductor digiti minimi (ADM, to obtain duration and area of ipsilateral silent period (ISP during simultaneous tonic contraction of APB and ADM. Data were compared with 13 controls who underwent twice these measurements, in a two-week interval, without undergoing piano training. Every subject in the experimental group improved keyboard performance and left-hand nine-hole peg test scores. Pre-training, ISP durations were asymmetrical, left being longer than right. Post-training, right ISPAPB increased, leading to symmetrical ISPAPB. Mu TRD during motor performance became more focal and had a lesser amplitude than in pre-training, due to decreased activity over ventral premotor cortices. No such changes were evidenced in controls. We demonstrated that a 10-day piano-training was associated with balanced interhemispheric interactions both at rest and during motor activation. Piano training, in a short timeframe, may reshape local and inter-hemispheric motor cortical circuits.

  3. Incidental Diagnosis of Cerebral Cortical Venous Thrombosis in Postdural Puncture Headache on Brain Computed Tomography.

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    Humbertjean, Lisa; Ducrocq, Xavier; Lacour, Jean-Christophe; Mione, Gioia; Richard, Sébastien

    2015-01-01

    Diagnosis of cerebral cortical venous thrombosis in patients with postdural puncture headache (PDPH) is usually secondary to changes in headache pattern or cerebral infarctions. Nevertheless, incidental discovery of asymptomatic forms on brain imaging has never been reported before and its management thus remains ill-defined. We describe 2 cases of patients with asymptomatic cortical vein thrombosis in the context of PDPH. In both cases, brain computed tomography (CT) scans showed an isolated cortical vein thrombosis without cerebral damage. Neurological examination revealed the typical orthostatic feature of PDPH, independently of cortical vein thrombosis which was considered as a radiological incidental finding. Clinical and radiological signs resolved after bed rest, oral caffeine, and anticoagulation therapy. Asymptomatic cortical vein thrombosis may be found on radiological exploration, even basic like brain CT scan without contrast, of PDPH. Utility of anticoagulation therapy, which could increase the risk of cerebral hemorrhagic complications in this specific context, has to be assessed.

  4. Cerebral blood flow in migraine and cortical spreading depression

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    Lauritzen, M.

    1987-01-01

    In a series of migraine patients, carotid arteriography was carried out as part of the clinical evalution. Nine patients developed a migrainous attack with focal neurological symptoms and headache after the angiography and during the subsequent, ongoing regional cerebral blood flow rCBF study. rCBF was measured by bolus injection of Xenon/sup 133/ into the internal carotid artery and a gamma camera with 254 collimated scintillation detectors covering the lateral aspect of the hemisphere. This technique depicts rCBF mainly at the level of the superficial cortex, with no depth resolution. The resolution is 1 cm/sup 2/ providing detailed spatial information of the cortical blood flow. Other methods for measuring local blood flow in animal and man employ a radioactive, freely diffusible tracer, in combination with an autoradiographic technique for the assessment of the tissue concentration, the so-called autoradiographic methods. In the series of patients with spontaneous migraine, rCBF was estimated using an in-vivo application of the autoradiographic principle. Xenon/sup 133/ was administered by inhalation and the time course of the arterial concentration curve was assessed by a scintillation detector over the upper right lung, since the arterial curve has been found to follow the shape of the lung curve. The rCBF was studied accompanying cortical spreading depression in rat experiments to evaluate wheter this phenomenon could explain the blood flow changes in migraine. (/sup 14/C) iodoantipyrine was given as an intravenous bolus injection and the brain content of indicator was determined by tissue sample or autoradiography after 10 or 20 seconds of isotope circulation. The conditions of the autoradiographic methods are that the flow remains constant within the period of measuring, and that the region under study is homogenous with regard to flow and lambda. (EG).

  5. Surgical Revascularization Reverses Cerebral Cortical Thinning in Patients With Severe Cerebrovascular Steno-Occlusive Disease

    NARCIS (Netherlands)

    Fierstra, Jorn; MacLean, David B.; Fisher, Joseph A.; Han, Jay S.; Mandell, Daniel M.; Conklin, John; Poublanc, Julien; Crawley, Adrian P.; Regli, Luca; Mikulis, David J.; Tymianski, Michael

    2011-01-01

    Background and Purpose-Chronic deficiencies in regional blood flow lead to cerebral cortical thinning without evidence of gross tissue loss at the same time as potentially negatively impacting on neurological and cognitive performance. This is most pronounced in patients with severe occlusive cerebr

  6. Cholinergic systems are essential for late-stage maturation and refinement of motor cortical circuits.

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    Ramanathan, Dhakshin S; Conner, James M; Anilkumar, Arjun A; Tuszynski, Mark H

    2015-03-01

    Previous studies reported that early postnatal cholinergic lesions severely perturb early cortical development, impairing neuronal cortical migration and the formation of cortical dendrites and synapses. These severe effects of early postnatal cholinergic lesions preclude our ability to understand the contribution of cholinergic systems to the later-stage maturation of topographic cortical representations. To study cholinergic mechanisms contributing to the later maturation of motor cortical circuits, we first characterized the temporal course of cortical motor map development and maturation in rats. In this study, we focused our attention on the maturation of cortical motor representations after postnatal day 25 (PND 25), a time after neuronal migration has been accomplished and cortical volume has reached adult size. We found significant maturation of cortical motor representations after this time, including both an expansion of forelimb representations in motor cortex and a shift from proximal to distal forelimb representations to an extent unexplainable by simple volume enlargement of the neocortex. Specific cholinergic lesions placed at PND 24 impaired enlargement of distal forelimb representations in particular and markedly reduced the ability to learn skilled motor tasks as adults. These results identify a novel and essential role for cholinergic systems in the late refinement and maturation of cortical circuits. Dysfunctions in this system may constitute a mechanism of late-onset neurodevelopmental disorders such as Rett syndrome and schizophrenia.

  7. [Preoperative direct cortical and sub-cortical electric stimulation during cerebral surgery in functional areas].

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    Duffau, H; Capelle, L; Sichez, J P; Bitar, A; Faillot, T; Arthuis, F; Van Effenterre, R; Fohanno, D

    1999-09-01

    Indications of surgical treatment for lesions in functional cerebral areas depend on the ratio between the definitive neurological deficit and the beneficial effect of resection. Detection of eloquent cortex is difficult because of important individual variability. Peroperative direct cortical and subcortical electrical stimulations (DCS) provide the most precise and reliable method currently available allowing identification and preservation of neurons essential for motricity, sensitivity++ and language. We report our preliminary experience with DCS in surgery of intracerebral infiltrative tumors with a consecutive series of 15 patients operated from November 96 through September 97 in our institution. Presenting symptoms in the 15 patients (8 males, 7 females, mean age 43 years) were seizures in 11 cases (73%) and neurological deficit in 4 cases (27%). Clinical examination was normal in 11 patients and revealed hemiparesia in 4. Magnetic resonance imaging (MRI) with three-dimensional reconstruction showed a precentral tumor in 10 cases, central lesion in one patient, postcentral lesion in two cases, right insular tumor (non-dominant hemisphere) in one case. All patients underwent surgical resection using DCS with detection in 13 cases of motor cortex and subcortical pathways under genera anesthesia, in one case of somatosensory area under local anesthesia, and in one case of language areas also under local anesthesia. The tumor was recurrent in two patients had been operated earlier but without DCS. Resection, verified by postoperative MRI, was total in 12 cases (80%) and estimated at 80% in 3 patients. Histological examination revealed an infiltrative glioma in 12 cases (8 low grade astrocytomas, 3 low grade oligodendrogliomas, and one anaplastic oligodendroglioma), and metastases in 3 cases. Eight patients had no postoperative deficit, while the other 7 patients were impaired, with, in all cases except one, complete recovery in 15 days to 2 months. Direct

  8. Cortical changes in cerebral small vessel diseases: a 3D MRI study of cortical morphology in CADASIL

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    Jouvent, E.; Bousser, M.G.; Chabriat, H. [CHU Lariboisiere, AP HP, INSERM, UMR 740, Dept Neurol, Lariboisiere (France); Jouvent, E.; Bousser, M.G.; Chabriat, H. [Univ Paris 07, F-75221 Paris 05 (France); Porcher, R. [Hop St Louis, AP-HP, Dept Biostat, St Louis (France); Viswanathan, A. [Massachusetts Gen Hosp, Dept Neurol, Boston, MA 02114 (United States); Viswanathan, A. [Massachusetts Gen Hosp, Clin Trials Unit, Boston, MA 02114 (United States); Viswanathan, A. [Harvard Univ, Sch Med, Boston, MA (United States); O' Sullivan, M.; Dichgans, M. [Univ Munich, Klinikum Grosshadern, Dept Neurol, D-81377 Munich (Germany); Guichard, J.P. [CHU Lariboisiere, AP-HP, Dept Neuroradiol, Lariboisiere (France)

    2008-07-01

    Brain atrophy represents a key marker of disease progression in cerebrovascular disorders. The 3D changes of cortex morphology occurring during the course of small vessel diseases of the brain (SVDB) remain poorly understood. The objective of this study was to assess the changes affecting depth and surface area of cortical sulci and their clinical and radiological correlates in a cohort of patients with cerebral autosomal dominant arteriolopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic SVDB. Data were obtained from a series of 69 CADASIL patients. Validated methods were used to determine depth and surface area of four cortical sulci. The ratio of brain to intracranial cavity volumes (brain parenchymal fraction-BPF), volume of lacunar lesions (LL) and of white matter hyper-intensities, number of cerebral micro-haemorrhages, and mean apparent diffusion coefficient were also measured. Association between depth and surface area of the cortical sulci and BPF, clinical status and subcortical MRI lesions were tested. Depth and surface area of cortical sulci obtained in 54 patients were strongly correlated with both cognitive score and disability scales. Depth was related to the extent of subcortical lesions, surface area was related only to age. In additional analyses, the depth of the cingular sulcus was independently associated with the volume of LL (P 0.001), and that of the superior frontal sulcus with the mean apparent diffusion coefficient (P 0.003). In CADASIL, important morphological changes of cortical sulci occur in association with clinical worsening,extension of subcortical tissue damage and progression of global cerebral atrophy. These results suggest that the examination of cortical morphology may be of high clinical relevance in SVDB. (authors)

  9. EFFECTS OF CEREBRAL CORTICAL CONCIS ON CELL PROLIFERATION OF THE SUBVENTRICULAR ZONE IN ADULT RATS

    Institute of Scientific and Technical Information of China (English)

    Zhang Yuelin; Qiu Shudong; Zhang Pengbo; Shi Wei

    2006-01-01

    Objective To investigate the proliferative response and time course of endogenous neural stem/progenitor cells after cerebral cortical concis in the adult rats. Methods Eighty adult male Sprague-Dawley rats were used in this study. Cumulative BrdU labeling was employed to detect the proliferating cells. At 1 d, 3 d, 7 d, 14 d, and 21 d after cerebral cortical concis, the rats were killed for BrdU immunohistochemical staining and cell counting in the injured ipsilateral SVZ. Results Little BrdU immunoreactivity cells was present in SVZ of the control rats from day 7 to day 21 after sham operation. The number of BrdU immunoreactivity cells in the injured ipsilateral SVZ increased at day 1 and peaked at day 7 after cerebral cortical concis. Conclusion After cerebral cortical concis of the adult rats, neural stem/progenitor cells in the injured ipsilateral SVZ markedly proliferated with a peak at day 7. This finding may be important for manipulating SVZ cells to promote the recovery from cerebral cortical concis.

  10. Integrated mechanisms of anticipation and rate-of-change computations in cortical circuits.

    Science.gov (United States)

    Puccini, Gabriel D; Sanchez-Vives, Maria V; Compte, Albert

    2007-05-01

    Local neocortical circuits are characterized by stereotypical physiological and structural features that subserve generic computational operations. These basic computations of the cortical microcircuit emerge through the interplay of neuronal connectivity, cellular intrinsic properties, and synaptic plasticity dynamics. How these interacting mechanisms generate specific computational operations in the cortical circuit remains largely unknown. Here, we identify the neurophysiological basis of both the rate of change and anticipation computations on synaptic inputs in a cortical circuit. Through biophysically realistic computer simulations and neuronal recordings, we show that the rate-of-change computation is operated robustly in cortical networks through the combination of two ubiquitous brain mechanisms: short-term synaptic depression and spike-frequency adaptation. We then show how this rate-of-change circuit can be embedded in a convergently connected network to anticipate temporally incoming synaptic inputs, in quantitative agreement with experimental findings on anticipatory responses to moving stimuli in the primary visual cortex. Given the robustness of the mechanism and the widespread nature of the physiological machinery involved, we suggest that rate-of-change computation and temporal anticipation are principal, hard-wired functions of neural information processing in the cortical microcircuit.

  11. Integrated mechanisms of anticipation and rate-of-change computations in cortical circuits.

    Directory of Open Access Journals (Sweden)

    Gabriel D Puccini

    2007-05-01

    Full Text Available Local neocortical circuits are characterized by stereotypical physiological and structural features that subserve generic computational operations. These basic computations of the cortical microcircuit emerge through the interplay of neuronal connectivity, cellular intrinsic properties, and synaptic plasticity dynamics. How these interacting mechanisms generate specific computational operations in the cortical circuit remains largely unknown. Here, we identify the neurophysiological basis of both the rate of change and anticipation computations on synaptic inputs in a cortical circuit. Through biophysically realistic computer simulations and neuronal recordings, we show that the rate-of-change computation is operated robustly in cortical networks through the combination of two ubiquitous brain mechanisms: short-term synaptic depression and spike-frequency adaptation. We then show how this rate-of-change circuit can be embedded in a convergently connected network to anticipate temporally incoming synaptic inputs, in quantitative agreement with experimental findings on anticipatory responses to moving stimuli in the primary visual cortex. Given the robustness of the mechanism and the widespread nature of the physiological machinery involved, we suggest that rate-of-change computation and temporal anticipation are principal, hard-wired functions of neural information processing in the cortical microcircuit.

  12. Molecular pathways underlying projection neuron production and migration during cerebral cortical development

    Directory of Open Access Journals (Sweden)

    Chiaki eOhtaka-Maruyama

    2015-12-01

    Full Text Available Glutamatergic neurons of the mammalian cerebral cortex originate from the radial glia (RG progenitors in the ventricular zone (VZ. During corticogenesis, neuroblasts migrate toward the pial surface using two different migration modes. One is multipolar (MP migration with random directional movement, and the other is locomotion, which is a unidirectional movement guided by the RG fiber. After reaching their final destination, the neurons finalize their migration by terminal translocation, which is followed by maturation via dendrite extension to initiate synaptogenesis and thereby complete neural circuit formation. This switching of migration modes during cortical development is unique in mammals, which suggests that the RG-guided locomotion mode may contribute to the evolution of the mammalian neocortical 6-layer structure. Many factors have been reported to be involved in the regulation of this radial neuronal migration process. In general, the radial migration can be largely divided into four steps; (1 maintenance and departure from the VZ of neural progenitor cells, (2 MP migration and transition to bipolar cells, (3 RG-guided locomotion, and (4 terminal translocation and dendrite maturation. Among these, many different gene mutations or knockdown effects have resulted in failure of the MP to bipolar transition (step 2, suggesting that it is a critical step, particularly in radial migration. Moreover, this transition occurs at the subplate layer. In this review, we summarize recent advances in our understanding of the molecular mechanisms underlying each of these steps. Finally, we discuss the evolutionary aspects of neuronal migration in corticogenesis.

  13. Inhibition-induced theta resonance in cortical circuits

    OpenAIRE

    Stark, Eran; Eichler, Ronny; Roux, Lisa; Fujisawa, Shigeyoshi; Rotstein, Horacio G.; Buzsáki, György

    2013-01-01

    Both circuit and single-cell properties contribute to network rhythms. In vitro, pyramidal cells exhibit theta-band membrane potential (subthreshold) resonance, but whether and how sub-threshold resonance translates into spiking resonance in behaving animals is unknown. Here, we used optogenetic activation to trigger spiking in pyramidal cells or parvalbumin immunoreactive interneurons (PV) in the hippocampus and neocortex of freely-behaving rodents. Individual directly-activated pyramidal ce...

  14. Dynamic Coding of Signed Quantities in Cortical Feedback Circuits

    Directory of Open Access Journals (Sweden)

    Dana eBallard

    2012-08-01

    Full Text Available In the early sensory and motor areas of the cortex, individual neurons transmit information about specific sensory features via a peaked response. This concept has been crystallized as `labeled lines,' to denote that axons communicate the specific properties of their sensory or motor parent cell. Such cells also can be characterized as being polarized, that is, as representing a signed quantity that is either positive or negative. We show in a model simulation that there are two important consequences when learning receptive fields using such signed codings in circuits that subtract different inputs. The first is that, in feedback circuits using labeled lines, such arithmetic operations need to be distributed across multiple distinct pathways. The second consequence is that such pathways must be necessarily dynamic, i.e. that synapses can grow and retract when forming receptive fields. The model monitors the breaking and growing of new circuit connections when their synapses need to change polarities and predicts that the rate of such changes should be inversely correlated with the progress of receptive field formation.

  15. Surgical Revascularization Reverses Cerebral Cortical Thinning in Patients With Severe Cerebrovascular Steno-Occlusive Disease

    NARCIS (Netherlands)

    Fierstra, Jorn; MacLean, David B.; Fisher, Joseph A.; Han, Jay S.; Mandell, Daniel M.; Conklin, John; Poublanc, Julien; Crawley, Adrian P.; Regli, Luca; Mikulis, David J.; Tymianski, Michael

    Background and Purpose-Chronic deficiencies in regional blood flow lead to cerebral cortical thinning without evidence of gross tissue loss at the same time as potentially negatively impacting on neurological and cognitive performance. This is most pronounced in patients with severe occlusive

  16. Effects of ketamine, midazolam, thiopental, and propofol on brain ischemia injury in rat cerebral cortical slices

    Institute of Scientific and Technical Information of China (English)

    Qing-shengXUE; Bu-weiYU; Ze-jianWANG; Hong-zhuanCHEN

    2004-01-01

    AIM: To compare the effects of ketamine, midazolam, thiopental, and propofol on brain ischemia by the model of oxygen-glucose deprivation (OGD) in rat cerebral cortical slices. METHODS: Cerebral cortical slices were incu-bated in 2 % 2,3,5-triphenyltetrazolium chloride (TTC) solution after OGD, the damages and effects of ketamine,midazolam, thiopental, and propofol were quantitativlye evaluated by ELISA reader of absorbance (A) at 490 nm,which indicated the red formazan extracted from slices, lactic dehydrogenase (LDH) releases in the incubated supernate were also measured. RESULTS: Progressive prolongation of OGD resulted in decreases of TTC staining.The percentage of tissue injury had a positive correlation with LDH releases, r=0.9609, P<0.01. Two hours of reincubation aggravated the decrease of TTC staining compared with those slices stained immediately after OGD(P<0.01). These four anesthetics had no effects on the TTC staining of slices. Ketamine completely inhibited thedecrease of A value induced by 10 min of OGD injury. High concentrations of midazolam (10 μmol/L) and thiopental (400μmol/L) partly attenuated this decrease. Propofol at high concentration (100 μmol/L) enhanced the decrease of A value induced by 10 min of OGD injury (P<0.01). CONCLUSION; Ketamine, high concentration of midazolam and thiopental have neuroprotective effects against OGD injury in rat cerebral cortical slices, while high concentration of propofol augments OGD injury in rat cerebral cortical slices.

  17. Increased interictal cerebral glucose metabolism in a cortical-subcortical network in drug naive patients with cryptogenic temporal lobe epilepsy.

    Science.gov (United States)

    Franceschi, M; Lucignani, G; Del Sole, A; Grana, C; Bressi, S; Minicucci, F; Messa, C; Canevini, M P; Fazio, F

    1995-01-01

    Positron emission tomography with [18F]-2-fluoro-2-deoxy-D-glucose ([18F]FDG) has been used to assess the pattern of cerebral metabolism in different types of epilepsies. However, PET with [18F]FDG has never been used to evaluate drug naive patients with cryptogenic temporal lobe epilepsy, in whom the mechanism of origin and diffusion of the epileptic discharge may differ from that underlying other epilepsies. In a group of patients with cryptogenic temporal lobe epilepsy, never treated with antiepileptic drugs, evidence has been found of significant interictal glucose hypermetabolism in a bilateral neural network including the temporal lobes, thalami, basal ganglia, and cingular cortices. The metabolism in these areas and frontal lateral cortex enables the correct classification of all patients with temporal lobe epilepsy and controls by discriminant function analysis. Other cortical areas--namely, frontal basal and lateral, temporal mesial, and cerebellar cortices--had bilateral increases of glucose metabolism ranging from 10 to 15% of normal controls, although lacking stringent statistical significance. This metabolic pattern could represent a pathophysiological state of hyperactivity predisposing to epileptic discharge generation or diffusion, or else a network of inhibitory circuits activated to prevent the diffusion of the epileptic discharge. PMID:7561924

  18. Trends and properties of human cerebral cortex: correlations with cortical myelin content.

    Science.gov (United States)

    Glasser, Matthew F; Goyal, Manu S; Preuss, Todd M; Raichle, Marcus E; Van Essen, David C

    2014-06-01

    "In vivo Brodmann mapping" or non-invasive cortical parcellation using MRI, especially by measuring cortical myelination, has recently become a popular research topic, though myeloarchitectonic cortical parcellation in humans previously languished in favor of cytoarchitecture. We review recent in vivo myelin mapping studies and discuss some of the different methods for estimating myelin content. We discuss some ways in which myelin maps may improve surface registration and be useful for cross-modal and cross-species comparisons, including some preliminary cross-species results. Next, we consider neurobiological aspects of why some parts of cortex are more myelinated than others. Myelin content is inversely correlated with intracortical circuit complexity - in general, more myelin content means simpler and perhaps less dynamic intracortical circuits. Using existing PET data and functional network parcellations, we examine metabolic differences in the differently myelinated cortical functional networks. Lightly myelinated cognitive association networks tend to have higher aerobic glycolysis than heavily myelinated early sensory-motor ones, perhaps reflecting greater ongoing dynamic anabolic cortical processes. This finding is consistent with the hypothesis that intracortical myelination may stabilize intracortical circuits and inhibit synaptic plasticity. Finally, we discuss the future of the in vivo myeloarchitectural field and cortical parcellation--"in vivo Brodmann mapping"--in general.

  19. Nerve transfer helps repair brachial plexus injury by increasing cerebral cortical plasticity

    Institute of Scientific and Technical Information of China (English)

    Guixin Sun; Zuopei Wu; Xinhong Wang; Xiaoxiao Tan; Yudong Gu

    2014-01-01

    In the treatment of brachial plexus injury, nerves that are functionally less important are trans-ferred onto the distal ends of damaged crucial nerves to help recover neuromuscular function in the target region. For example, intercostal nerves are transferred onto axillary nerves, and accessory nerves are transferred onto suprascapular nerves, the phrenic nerve is transferred onto the musculocutaneous nerves, and the contralateral C7 nerve is transferred onto the median or radial nerves. Nerve transfer has become a major method for reconstructing the brachial plexus after avulsion injury. Many experiments have shown that nerve transfers for treatment of brachi-al plexus injury can help reconstruct cerebral cortical function and increase cortical plasticity. In this review article, we summarize the recent progress in the use of diverse nerve transfer methods for the repair of brachial plexus injury, and we discuss the impact of nerve transfer on cerebral cortical plasticity after brachial plexus injury.

  20. Stochastic transitions into silence cause noise correlations in cortical circuits.

    Science.gov (United States)

    Mochol, Gabriela; Hermoso-Mendizabal, Ainhoa; Sakata, Shuzo; Harris, Kenneth D; de la Rocha, Jaime

    2015-03-17

    The spiking activity of cortical neurons is highly variable. This variability is generally correlated among nearby neurons, an effect commonly interpreted to reflect the coactivation of neurons due to anatomically shared inputs. Recent findings, however, indicate that correlations can be dynamically modulated, suggesting that the underlying mechanisms are not well understood. Here, we investigate the hypothesis that correlations are dominated by neuronal coinactivation: the occurrence of brief silent periods during which all neurons in the local network stop firing. We recorded spiking activity from large populations of neurons in the auditory cortex of anesthetized rats across different brain states. During spontaneous activity, the reduction of correlation accompanying brain state desynchronization was largely explained by a decrease in the density of the silent periods. The presentation of a stimulus caused an initial drop of correlations followed by a rebound, a time course that was mimicked by the instantaneous silence density. We built a rate network model with fluctuation-driven transitions between a silent and an active attractor and assumed that neurons fired Poisson spike trains with a rate following the model dynamics. Variations of the network external input altered the transition rate into the silent attractor and reproduced the relation between correlation and silence density found in the data, both in spontaneous and evoked conditions. This suggests that the observed changes in correlation, occurring gradually with brain state variations or abruptly with sensory stimulation, are due to changes in the likeliness of the microcircuit to transiently cease firing.

  1. Human cerebral cortices: signal variation on diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Asao, Chiaki [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Hirai, Toshinori; Yamashita, Yasuyuki [Kumamoto University Graduate School of Medical Sciences, Department of Diagnostic Radiology, Kumamoto (Japan); Yoshimatsu, Shunji [National Hospital Organization Kumamoto Medical Center, Department of Radiology, Kumamoto (Japan); Matsukawa, Tetsuya; Imuta, Masanori [Kumamoto Regional Medical Center, Department of Radiology, Kumamoto (Japan); Sagara, Katsuro [Kumamoto Regional Medical Center, Department of Internal Medicine, Kumamoto (Japan)

    2008-03-15

    We have often encountered high signal intensity (SI) of the cingulate gyrus and insula during diffusion-weighted magnetic resonance imaging (DW-MRI) on neurologically healthy adults. To date, cortical signal heterogeneity on DW images has not been investigated systematically. The purpose of our study was to determine whether there is regional signal variation in the brain cortices of neurologically healthy adults on DW-MR images. The SI of the cerebral cortices on DW-MR images at 1.5 T was evaluated in 50 neurologically healthy subjects (34 men, 16 women; age range 33-84 years; mean age 57.6 years). The cortical SI in the cingulate gyrus, insula, and temporal, occipital, and parietal lobes was graded relative to the SI of the frontal lobe. Contrast-to-noise ratios (CNRs) on DW-MR images were compared for each cortical area. Diffusion changes were analyzed by visually assessment of the differences in appearance among the cortices on apparent diffusion coefficient (ADC) maps. Increased SI was frequently seen in the cingulate gyrus and insula regardless of patient age. There were no significant gender- or laterality-related differences. The CNR was significantly higher in the cingulate gyrus and insula than in the other cortices (p <.01), and significant differences existed among the cortical regions (p <.001). There were no apparent ADC differences among the cortices on ADC maps. Regional signal variation of the brain cortices was observed on DW-MR images of healthy subjects, and the cingulate gyrus and insula frequently manifested high SI. These findings may help in the recognition of cortical signal abnormalities as visualized on DW-MR images. (orig.)

  2. Developmental regulation of spatio-temporal patterns of cortical circuit activation

    Directory of Open Access Journals (Sweden)

    Trevor Charles Griffen

    2013-01-01

    Full Text Available Neural circuits are refined in an experience-dependent manner during early postnatal development. How development modulates the spatio-temporal propagation of activity through cortical circuits is poorly understood. Here we use voltage sensitive dye imaging (VSD to show that there are significant changes in the spatio-temporal patterns of intracortical signals in primary visual cortex from postnatal day 13 (P13, eye opening, to P28, the peak of the critical period for rodent visual cortical plasticity. Upon direct stimulation of layer 4 (L4, activity spreads to L2/3 and to L5 at all ages. However, while from eye opening to the peak of the critical period, the amplitude and persistence of the voltage signal decrease, peak activation is reached more quickly and the interlaminar gain increases with age. The lateral spread of activation within layers remains unchanged throughout the time window under analysis. These developmental changes in spatio-temporal patterns of intracortical circuit activation are mediated by differences in the contributions of excitatory and inhibitory synaptic components. Our results demonstrate that after eye opening the circuit in primary visual cortex is refined through a progression of changes that shape the spatio-temporal patterns of circuit activation. Signals become more efficiently propagated across layers through developmentally regulated changes in interlaminar gain.

  3. Genome-wide divergence of DNA methylation marks in cerebral and cerebellar cortices.

    Directory of Open Access Journals (Sweden)

    Yurong Xin

    Full Text Available BACKGROUND: Emerging evidence suggests that DNA methylation plays an expansive role in the central nervous system (CNS. Large-scale whole genome DNA methylation profiling of the normal human brain offers tremendous potential in understanding the role of DNA methylation in brain development and function. METHODOLOGY/SIGNIFICANT FINDINGS: Using methylation-sensitive SNP chip analysis (MSNP, we performed whole genome DNA methylation profiling of the prefrontal, occipital, and temporal regions of cerebral cortex, as well as cerebellum. These data provide an unbiased representation of CpG sites comprising 377,509 CpG dinucleotides within both the genic and intergenic euchromatic region of the genome. Our large-scale genome DNA methylation profiling reveals that the prefrontal, occipital, and temporal regions of the cerebral cortex compared to cerebellum have markedly different DNA methylation signatures, with the cerebral cortex being hypermethylated and cerebellum being hypomethylated. Such differences were observed in distinct genomic regions, including genes involved in CNS function. The MSNP data were validated for a subset of these genes, by performing bisulfite cloning and sequencing and confirming that prefrontal, occipital, and temporal cortices are significantly more methylated as compared to the cerebellum. CONCLUSIONS: These findings are consistent with known developmental differences in nucleosome repeat lengths in cerebral and cerebellar cortices, with cerebrum exhibiting shorter repeat lengths than cerebellum. Our observed differences in DNA methylation profiles in these regions underscores the potential role of DNA methylation in chromatin structure and organization in CNS, reflecting functional specialization within cortical regions.

  4. Distribution of neurons in functional areas of the mouse cerebral cortex reveals quantitatively different cortical zones.

    Science.gov (United States)

    Herculano-Houzel, Suzana; Watson, Charles; Paxinos, George

    2013-01-01

    How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes-with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative. These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later.

  5. Continuous nimodipine treatment attenuates cortical infarction in rats subjected to 24 hours of focal cerebral ischemia.

    Science.gov (United States)

    Jacewicz, M; Brint, S; Tanabe, J; Pulsinelli, W A

    1990-01-01

    Focal cerebral infarction and edema were measured in rats (Wistar, Fisher 344, and spontaneously hypertensive strains) pretreated with nimodipine (2 micrograms/kg/min i.v.) or its vehicle and subjected to the tandem occlusion of the middle cerebral and common carotid arteries. Animals awoke from anesthesia 10-15 min after onset of ischemia and continued to receive treatment over a 24-h survival period. Cortical infarction and edema were quantified by image analysis of frozen brain sections processed for histology. Nimodipine-treated rats developed 20-60% smaller cortical infarct volumes than controls (p less than 0.002). Cortical edema was reduced proportionately to the decrease in infarct volume and constituted approximately 36% of the infarct volume. Nimodipine caused a mild hypotensive response that did not aggravate ischemic brain damage. The results indicate that continuous nimodipine treatment, started before induction of focal cerebral ischemia, can attenuate ischemic brain damage and edema as late as 24 h after the onset of ischemia.

  6. Subcortical cerebral blood flow and metabolic changes elicited by cortical spreading depression in rat

    Energy Technology Data Exchange (ETDEWEB)

    Mraovitch, S.; Calando, Y.; Goadsby, P.J.; Seylaz, J. (Laboratoire de Recherches Cerebrovasculaire, Paris (France))

    1992-06-01

    Changes in cerebral cortical perfusion (CBF{sub LDF}), local cerebral blood flow (lCBF) and local cerebral glucose utilization (lCGU) elicited by unilateral cortical spreading depression (SD) were monitored and measured in separate groups of rats anesthetized with {alpha}-chloralose. CBF{sub LDF} was recorded with laser Doppler flowmetry, while lCBF and lCGU were measured by the quantitative autoradiographic ({sup 14}C)iodoantipyrine and ({sup 14}C)-2-deoxyglucose methods, respectively. SD elicited a wave of hyperemia after a latency of 2 to 3 min followed by an oligemic phase. Ninety minutes following the onset of SD cortical lCBF and lCGU were essentially the same as on the contralateral side and in sham-treated rats. However, alteration in the lCBF and lCGU in upper and lower brainstem persisted. The present results demonstrate that long-lasting cerebrovascular and metabolic alterations take place within the subcortical regions following SD. These regions provide an attractive site to integrate observations in man concerning spreading depression and the aura of migraine with the other features of the syndrome. 19 refs., 2 figs., 1 tab.

  7. LTS and FS inhibitory interneurons, short-term synaptic plasticity, and cortical circuit dynamics.

    Directory of Open Access Journals (Sweden)

    Itai Hayut

    2011-10-01

    Full Text Available Somatostatin-expressing, low threshold-spiking (LTS cells and fast-spiking (FS cells are two common subtypes of inhibitory neocortical interneuron. Excitatory synapses from regular-spiking (RS pyramidal neurons to LTS cells strongly facilitate when activated repetitively, whereas RS-to-FS synapses depress. This suggests that LTS neurons may be especially relevant at high rate regimes and protect cortical circuits against over-excitation and seizures. However, the inhibitory synapses from LTS cells usually depress, which may reduce their effectiveness at high rates. We ask: by which mechanisms and at what firing rates do LTS neurons control the activity of cortical circuits responding to thalamic input, and how is control by LTS neurons different from that of FS neurons? We study rate models of circuits that include RS cells and LTS and FS inhibitory cells with short-term synaptic plasticity. LTS neurons shift the RS firing-rate vs. current curve to the right at high rates and reduce its slope at low rates; the LTS effect is delayed and prolonged. FS neurons always shift the curve to the right and affect RS firing transiently. In an RS-LTS-FS network, FS neurons reach a quiescent state if they receive weak input, LTS neurons are quiescent if RS neurons receive weak input, and both FS and RS populations are active if they both receive large inputs. In general, FS neurons tend to follow the spiking of RS neurons much more closely than LTS neurons. A novel type of facilitation-induced slow oscillations is observed above the LTS firing threshold with a frequency determined by the time scale of recovery from facilitation. To conclude, contrary to earlier proposals, LTS neurons affect the transient and steady state responses of cortical circuits over a range of firing rates, not only during the high rate regime; LTS neurons protect against over-activation about as well as FS neurons.

  8. Intraoperative imaging of cortical cerebral perfusion by time-resolved thermography and multivariate data analysis

    Science.gov (United States)

    Steiner, Gerald; Sobottka, Stephan B.; Koch, Edmund; Schackert, Gabriele; Kirsch, Matthias

    2011-01-01

    A new approach to cortical perfusion imaging is demonstrated using high-sensitivity thermography in conjunction with multivariate statistical data analysis. Local temperature changes caused by a cold bolus are imaged and transferred to a false color image. A cold bolus of 10 ml saline at ice temperature is injected systemically via a central venous access. During the injection, a sequence of 735 thermographic images are recorded within 2 min. The recorded data cube is subjected to a principal component analysis (PCA) to select slight changes of the cortical temperature caused by the cold bolus. PCA reveals that 11 s after injection the temperature of blood vessels is shortly decreased followed by an increase to the temperature before the cold bolus is injected. We demonstrate the potential of intraoperative thermography in combination with multivariate data analysis to image cortical cerebral perfusion without any markers. We provide the first in vivo application of multivariate thermographic imaging.

  9. Canonical Cortical Circuit Model Explains Rivalry, Intermittent Rivalry, and Rivalry Memory.

    Directory of Open Access Journals (Sweden)

    Shashaank Vattikuti

    2016-05-01

    Full Text Available It has been shown that the same canonical cortical circuit model with mutual inhibition and a fatigue process can explain perceptual rivalry and other neurophysiological responses to a range of static stimuli. However, it has been proposed that this model cannot explain responses to dynamic inputs such as found in intermittent rivalry and rivalry memory, where maintenance of a percept when the stimulus is absent is required. This challenges the universality of the basic canonical cortical circuit. Here, we show that by including an overlooked realistic small nonspecific background neural activity, the same basic model can reproduce intermittent rivalry and rivalry memory without compromising static rivalry and other cortical phenomena. The background activity induces a mutual-inhibition mechanism for short-term memory, which is robust to noise and where fine-tuning of recurrent excitation or inclusion of sub-threshold currents or synaptic facilitation is unnecessary. We prove existence conditions for the mechanism and show that it can explain experimental results from the quartet apparent motion illusion, which is a prototypical intermittent rivalry stimulus.

  10. A proteomic survey of rat cerebral cortical synaptosomes.

    Science.gov (United States)

    Witzmann, Frank A; Arnold, Randy J; Bai, Fengju; Hrncirova, Petra; Kimpel, Mark W; Mechref, Yehia S; McBride, William J; Novotny, Milos V; Pedrick, Nathan M; Ringham, Heather N; Simon, Jay R

    2005-05-01

    Previous findings from our laboratory and others indicate that two-dimensional gel electrophoresis (2-DE) can be used to study protein expression in defined brain regions, but mainly the proteins which are present in high abundance in glia are readily detected. The current study was undertaken to determine the protein profile in a synaptosomal subcellular fraction isolated from the cerebral cortex of the rat. Both 2-DE and liquid chromatography - tandem mass spectrometry (LC-MS/MS) procedures were used to isolate and identify proteins in the synaptosomal fraction and accordingly >900 proteins were detected using 2-DE; the 167 most intense gel spots were isolated and identified with matrix-assisted laser desorption/ionization - time of flight peptide mass fingerprinting or LC-MS/MS. In addition, over 200 proteins were separated and identified with the LC-MS/MS "shotgun proteomics" technique, some in post-translationally modified form. The following classes of proteins associated with synaptic function were detected: (a) proteins involved in synaptic vesicle trafficking-docking (e.g., SNAP-25, synapsin I and II, synaptotagmin I, II, and V, VAMP-2, syntaxin 1A and 1B, etc.); (b) proteins that function as transporters or receptors (e.g., excitatory amino acid transporters 1 and 2, GABA transporter 1); (c) proteins that are associated with the synaptic plasma membrane (e.g., post-synaptic density-95/synapse-associated protein-90 complex, neuromodulin (GAP-43), voltage-dependent anion-selective channel protein (VDACs), sodium-potassium ATPase subunits, alpha 2 spectrin, septin 7, etc.); and (d) proteins that mediate intracellular signaling cascades that modulate synaptic function (e.g., calmodulin, calcium-calmodulin-dependent protein kinase subunits, etc.). Other identified proteins are associated with mitochondrial or general cytosolic function. Of the two proteins identified as endoplasmic reticular, both interact with the synaptic SNARE complex to regulate vesicle

  11. CT and MRI findings of cerebral ischemic lesions in the cortical and perforating arterial system

    Energy Technology Data Exchange (ETDEWEB)

    Kameyama, Masakuni; Udaka, Fukashi; Nishinaka, Kazuto; Kodama, Mitsuo; Urushidani, Makoto; Kawamura, Kazuyuki; Inoue, Haruhisa; Kageyama, Taku [Sumitomo Hospital, Osaka (Japan)

    1995-07-01

    It is clinically useful to divide the location of infarction into the cortical and perforating arterial system. Computerized tomography (CT) and magnetic resonance imaging (MRI) now make the point of infarction a simple and useful task in daily practice. The diagnostic modality has also demonstrated that risk factors and clinical manifestations are different for infarction in the cortical as opposed to the perforating system. In this paper, we present various aspects of images of cerebral ischemia according to CT and/or MRI findings. With the advance of imaging mechanics, diagnostic capability of CT or/and MRI for cerebral infarction has markedly been improved. We must consider these points on evaluating the previously reported results. In addition, we always consider the pathological background of these image-findings for the precise interpretation of their clinical significance. In some instances, dynamic study such as PET or SPECT is needed for real interpretations of CT and/or MRI images. We paid special reference to lacunar stroke and striatocapsular infarct. In addition, `branch atheromatous disease (Caplan)` was considered, in particular, for their specific clinical significances. Large striatocapsular infarcts frequently show cortical signs and symptoms such as aphasia or agnosia in spite of their subcortical localization. These facts, although have previously been known, should be re-considered for their pathoanatomical mechanism. (author).

  12. Disappearance of cerebral cortical atrophy following replacement therapy with vitamin B12 in an infant

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    Ebru Yilmaz Keskin

    2016-03-01

    Full Text Available Vitamin B12 (cobalamin deficiency during infancy is seen most commonly in exclusively breast-fed infants born to mothers with inadequate vitamin B12 stores. In addition to megaoblastic anemia, physical, social and neuromotor retardation may be seen in affected patients. In severe cases, thrombocytopenia and neutropenia may accompany anemia mimicking leukemia or aplastic anemia. Patients may rarely develop cerebral cortical atrophy evident on neuroimaging. In this article, a 12-month-old female infant with psychomotor developmental retardation who was referred to our hospital with the initial diagnosis of leukemia due to the finding of pancytopenia is presented. Further investigations revealed severe nutritional vitamin B12 deficiency in this case. Cranial magnetic resonance imaging (MRI showed cerebral cortical atrophy. Replacement therapy with vitamin B12 resulted in marked improvement of psychomotor status, and cranial MRI performed 7 months following the diagnosis and treatment initiation revealed resolution of cortical atrophy. [Cukurova Med J 2016; 41(1.000: 152-160

  13. Neuropeptide Y protects cerebral cortical neurons by regulating microglial immune function

    Institute of Scientific and Technical Information of China (English)

    Qijun Li; Changzheng Dong; Wenling Li; Wei Bu; Jiang Wu; Wenqing Zhao

    2014-01-01

    Neuropeptide Y has been shown to inhibit the immunological activity of reactive microglia in the rat cerebral cortex, to reduce N-methyl-D-aspartate current (INMDA) in cortical neurons, and protect neurons. In this study, after primary cultured microglia from the cerebral cortex of rats were treated with lipopolysaccharide, interleukin-1β and tumor necrosis factor-α levels in the cell culture medium increased, and mRNA expression of these cytokines also increased. After primary cultured cortical neurons were incubated with the lipopolysaccharide-treated microg-lial conditioned medium, peak INMDA in neurons increased. These effects of lipopolysaccharide were suppressed by neuropeptide Y. After addition of the neuropeptide Y Y1 receptor antago-nist BIBP3226, the effects of neuropeptide Y completely disappeared. These results suggest that neuropeptide Y prevents excessive production of interleukin-1β and tumor necrosis factor-α by inhibiting microglial reactivity. This reduces INMDA in rat cortical neurons, preventing excitotoxic-ity, thereby protecting neurons.

  14. Upper limb function and cortical organisation in youth with hemiplegic, cerebral palsy

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    Anna eMackey

    2014-07-01

    Full Text Available Aim: To explore the relationship between motor cortical and descending motor pathway reorganisation, lesion type and upper limb function in youth with unilateral cerebral palsy. Methods: Twenty participants with unilateral cerebral palsy (mean age 15 ± 3 years; 11 males completed a range of upper limb functional measures. Structural MRI, diffusion weighted and functional MR imaging were conducted to determine type and extent of brain lesion, descending white matter integrity, and whole-brain activity during affected hand use. Single pulse transcranial magnetic stimulation (n = 12 was used to examine functional integrity of the corticospinal pathway as well as primary motor cortex intracortical and interhemispheric inhibition from motor evoked potentials and silent periods.Results: Fractional anisotropy measures within the posterior limb of the internal capsule were a predictor of upper limb function (R2 = 0.41, F = 11.3, p = 0.004. Participants with periventricular lesions tended to have better upper limb function (F (2, 17 = 42.48, p < 0.0001. Five participants with evidence of cortical reorganisation and functional ipsilateral projections to their affected hand had worse upper limb function. Deficits in intracortical and interhemispheric inhibitory mechanisms were found in participants with worse upper limb function (Melbourne Assessment of Unilateral Upper Limb Function: Mann Whitney p = 0.02.Conclusions: Neuroimaging and transcranial magnetic stimulation can provide useful information related to hand function of individuals with unilateral cerebral palsy and may have potential to assist as a predictive tool and / or guide rehabilitation.

  15. Differences in cerebral cortical anatomy of left- and right-handers

    Science.gov (United States)

    Guadalupe, Tulio; Willems, Roel M.; Zwiers, Marcel P.; Arias Vasquez, Alejandro; Hoogman, Martine; Hagoort, Peter; Fernandez, Guillen; Buitelaar, Jan; Franke, Barbara; Fisher, Simon E.; Francks, Clyde

    2014-01-01

    The left and right sides of the human brain are specialized for different kinds of information processing, and much of our cognition is lateralized to an extent toward one side or the other. Handedness is a reflection of nervous system lateralization. Roughly ten percent of people are mixed- or left-handed, and they show an elevated rate of reductions or reversals of some cerebral functional asymmetries compared to right-handers. Brain anatomical correlates of left-handedness have also been suggested. However, the relationships of left-handedness to brain structure and function remain far from clear. We carried out a comprehensive analysis of cortical surface area differences between 106 left-handed subjects and 1960 right-handed subjects, measured using an automated method of regional parcellation (FreeSurfer, Destrieux atlas). This is the largest study sample that has so far been used in relation to this issue. No individual cortical region showed an association with left-handedness that survived statistical correction for multiple testing, although there was a nominally significant association with the surface area of a previously implicated region: the left precentral sulcus. Identifying brain structural correlates of handedness may prove useful for genetic studies of cerebral asymmetries, as well as providing new avenues for the study of relations between handedness, cerebral lateralization and cognition. PMID:24734025

  16. Differences in cerebral cortical anatomy of left- and right-handers

    Directory of Open Access Journals (Sweden)

    Tulio eGuadalupe

    2014-03-01

    Full Text Available The left and right sides of the human brain are specialized for different kinds of information processing, and much of our cognition is lateralized to an extent towards one side or the other. Handedness is a reflection of nervous system lateralization. Roughly ten percent of people are mixed- or left-handed, and they show an elevated rate of reductions or reversals of some cerebral functional asymmetries compared to right-handers. Brain anatomical correlates of left-handedness have also been suggested. However, the relationships of left-handedness to brain structure and function remain far from clear. We carried out a comprehensive analysis of cortical surface area differences between 106 left-handed subjects and 1960 right-handed subjects, measured using an automated method of regional parcellation (FreeSurfer, Destrieux atlas. This is the largest study sample that has so far been used in relation to this issue. No individual cortical region showed an association with left-handedness that survived statistical correction for multiple testing, although there was a nominally significant association with the surface area of a previously implicated region: the left precentral sulcus. Identifying brain structural correlates of handedness may prove useful for genetic studies of cerebral asymmetries, as well as providing new avenues for the study of relations between handedness, cerebral lateralization and cognition.

  17. An automated pipeline for cortical surface generation and registration of the cerebral cortex

    Science.gov (United States)

    Li, Wen; Ibanez, Luis; Gelas, Arnaud; Yeo, B. T. Thomas; Niethammer, Marc; Andreasen, Nancy C.; Magnotta, Vincent A.

    2011-03-01

    The human cerebral cortex is one of the most complicated structures in the body. It has a highly convoluted structure with much of the cortical sheet buried in sulci. Based on cytoarchitectural and functional imaging studies, it is possible to segment the cerebral cortex into several subregions. While it is only possible to differentiate the true anatomical subregions based on cytoarchitecture, the surface morphometry aligns closely with the underlying cytoarchitecture and provides features that allow the surface of the cortex to be parcellated based on the sulcal and gyral patterns that are readily visible on the MR images. We have developed a fully automated pipeline for the generation and registration of cortical surfaces in the spherical domain. The pipeline initiates with the BRAINS AutoWorkup pipeline. Subsequently, topology correction and surface generation is performed to generate a genus zero surface and mapped to a sphere. Several surface features are then calculated to drive the registration between the atlas surface and other datasets. A spherical diffeomorphic demons algorithm is used to co-register an atlas surface onto a subject surface. A lobar based atlas of the cerebral cortex was created from a manual parcellation of the cortex. The atlas surface was then co-registered to five additional subjects using a spherical diffeomorphic demons algorithm. The labels from the atlas surface were warped on the subject surface and compared to the manual raters. The average Dice overlap index was 0.89 across all regions.

  18. Effects of homeostatic constraints on associative memory storage and synaptic connectivity of cortical circuits

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    Julio eChapeton

    2015-06-01

    Full Text Available The impact of learning and long-term memory storage on synaptic connectivity is not completely understood. In this study, we examine the effects of associative learning on synaptic connectivity in adult cortical circuits by hypothesizing that these circuits function in a steady-state, in which the memory capacity of a circuit is maximal and learning must be accompanied by forgetting. Steady-state circuits should be characterized by unique connectivity features. To uncover such features we developed a biologically constrained, exactly solvable model of associative memory storage. The model is applicable to networks of multiple excitatory and inhibitory neuron classes and can account for homeostatic constraints on the number and the overall weight of functional connections received by each neuron. The results show that in spite of a large number of neuron classes, functional connections between potentially connected cells are realized with less than 50% probability if the presynaptic cell is excitatory and generally a much greater probability if it is inhibitory. We also find that constraining the overall weight of presynaptic connections leads to Gaussian connection weight distributions that are truncated at zero. In contrast, constraining the total number of functional presynaptic connections leads to non-Gaussian distributions, in which weak connections are absent. These theoretical predictions are compared with a large dataset of published experimental studies reporting amplitudes of unitary postsynaptic potentials and probabilities of connections between various classes of excitatory and inhibitory neurons in the cerebellum, neocortex, and hippocampus.

  19. Interhemispheric claustral circuits coordinate somatomotor and visuomotor cortical areas that regulate exploratory behaviors

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    Jared Brent Smith

    2014-05-01

    Full Text Available The claustrum has a role in the interhemispheric transfer of certain types of sensorimotor information. Whereas the whisker region in rat motor (M1 cortex sends dense projections to the contralateral claustrum, the M1 forelimb representation does not. The claustrum sends strong ipsilateral projections to the whisker regions in M1 and somatosensory (S1 cortex, but its projections to the forelimb cortical areas are weak. These distinctions suggest that one function of the M1 projections to the contralateral claustrum is to coordinate the cortical areas that regulate peripheral sensor movements during behaviors that depend on bilateral sensory acquisition. If this hypothesis is true, then similar interhemispheric circuits should interconnect the frontal eye fields (FEF with the contralateral claustrum and its network of projections to vision-related cortical areas. To test this hypothesis, anterograde and retrograde tracers were placed in physiologically-defined parts of the FEF and primary visual cortex (V1 in rats. We observed dense FEF projections to the contralateral claustrum that terminated in the midst of claustral neurons that project to both FEF and V1. While the FEF inputs to the claustrum come predominantly from the contralateral hemisphere, the claustral projections to FEF and V1 are primarily ipsilateral. Detailed comparison of the present results with our previous studies on somatomotor claustral circuitry revealed a well-defined functional topography in which the ventral claustrum is connected with visuomotor cortical areas and the dorsal regions are connected with somatomotor areas. These results suggest that subregions within the claustrum play a critical role in coordinating the cortical areas that regulate the acquisition of modality-specific sensory information during exploration and other behaviors that require sensory attention.

  20. Cortical subarachnoid hemorrhage associated with reversible cerebral vasoconstriction syndrome after elective triplet cesarean delivery.

    Science.gov (United States)

    Albano, Beatrice; Del Sette, Massimo; Roccatagliata, Luca; Gandolfo, Carlo; Primavera, Alberto

    2011-06-01

    Reversible cerebral vasoconstriction syndromes (RCVS) comprise a group of disorders characterized by prolonged, but reversible vasoconstriction of the cerebral arteries, usually associated with acute-onset, severe, recurrent headaches, with or without additional neurological signs and symptoms. Various complications of this condition have been observed, such as cortical subarachnoid hemorrhages (cSAH), intracerebral hemorrhages, reversible posterior leukoencephalopathy, ischaemic strokes and transient ischaemic attacks. It is important to include RCVS in thunderclap headache differential diagnosis and among non-aneurismatic subarachnoid hemorrhage causes. In the past years, thanks to the major diffusion of new diagnostic tools such as magnetic resonance, computed tomography and digital subtraction angiography, RCVS have been demonstrated to be more frequent than previously thought. We report an illustrative case of a woman affected by a small cSAH, associated to RCVS, after elective triplet cesarean delivery. To our knowledge, this is the first case of cSAH associated to RCVS after a triplet pregnancy.

  1. Reversible Cortical Blindness as a Prominent Manifestation of Cerebral Embolism due to Infective Endocarditis

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    Georgios P. Kranidiotis

    2010-01-01

    Full Text Available Introduction. Infective endocarditis in the left heart may be complicated by stroke, due to embolisation from infectious valvular vegetations. Infarction of both occipital lobes, which are supplied by the posterior cerebral arteries, is infrequent, and is the cause of cortical blindness from lesion of the visual cortex. Cortical blindness is characterized by intact pupillary reflexes, a normal fundoscopy, and, rarely, denial of visual loss. Case Presentation. We report the case of a 58-year-old woman, recipient of a mechanical aortic valve, who presented with fever, multiple organ dysfunction, and cortical blindness. Transesophageal echocardiography and blood cultures confirmed the diagnosis of infective endocarditis caused by methicillin-sensitive Staphylococcus aureus. Computed tomography of the brain without contrast revealed the presence of infarctions in both occipital lobes. It is noteworthy that the visual loss resolved after treatment of endocarditis. Conclusions. A stroke occurring in a patient presenting with fever and a history of valvular heart disease strongly suggests the presence of infective endocarditis. Bilateral thromboembolic infarcts of the occipital lobes cause cortical blindness, that can resolve after treatment of endocarditis.

  2. Reversible Cortical Blindness as a Prominent Manifestation of Cerebral Embolism due to Infective Endocarditis.

    Science.gov (United States)

    Kranidiotis, Georgios P; Gougoutsi, Alexandra N; Retsas, Theodoros A; Anastasiou-Nana, Maria I

    2010-01-01

    Introduction. Infective endocarditis in the left heart may be complicated by stroke, due to embolisation from infectious valvular vegetations. Infarction of both occipital lobes, which are supplied by the posterior cerebral arteries, is infrequent, and is the cause of cortical blindness from lesion of the visual cortex. Cortical blindness is characterized by intact pupillary reflexes, a normal fundoscopy, and, rarely, denial of visual loss. Case Presentation. We report the case of a 58-year-old woman, recipient of a mechanical aortic valve, who presented with fever, multiple organ dysfunction, and cortical blindness. Transesophageal echocardiography and blood cultures confirmed the diagnosis of infective endocarditis caused by methicillin-sensitive Staphylococcus aureus. Computed tomography of the brain without contrast revealed the presence of infarctions in both occipital lobes. It is noteworthy that the visual loss resolved after treatment of endocarditis. Conclusions. A stroke occurring in a patient presenting with fever and a history of valvular heart disease strongly suggests the presence of infective endocarditis. Bilateral thromboembolic infarcts of the occipital lobes cause cortical blindness, that can resolve after treatment of endocarditis.

  3. Brain circuit-gene expression relationships and neuroplasticity of multisensory cortices in blind children.

    Science.gov (United States)

    Ortiz-Terán, Laura; Diez, Ibai; Ortiz, Tomás; Perez, David L; Aragón, Jose Ignacio; Costumero, Victor; Pascual-Leone, Alvaro; El Fakhri, Georges; Sepulcre, Jorge

    2017-06-27

    Sensory deprivation reorganizes neurocircuits in the human brain. The biological basis of such neuroplastic adaptations remains elusive. In this study, we applied two complementary graph theory-based functional connectivity analyses, one to evaluate whole-brain functional connectivity relationships and the second to specifically delineate distributed network connectivity profiles downstream of primary sensory cortices, to investigate neural reorganization in blind children compared with sighted controls. We also examined the relationship between connectivity changes and neuroplasticity-related gene expression profiles in the cerebral cortex. We observed that multisensory integration areas exhibited enhanced functional connectivity in blind children and that this reorganization was spatially associated with the transcription levels of specific members of the cAMP Response Element Binding protein gene family. Using systems-level analyses, this study advances our understanding of human neuroplasticity and its genetic underpinnings following sensory deprivation.

  4. Optical coherence tomography reveals in vivo cortical structures of adult rats in response to cerebral ischemia injury

    Science.gov (United States)

    Ni, Yi-rong; Guo, Zhou-yi; Shu, So-yun; Bao, Xin-min

    2008-12-01

    Optical coherence tomography(OCT) is a high resolution imaging technique which uses light to directly image living tissue. we investigate the potential use of OCT for structural imaging of the ischemia injury mammalian cerebral cortex. And we examine models of middle cerebral artery occlusion (MCAO) in rats in vivo using OCT. In particular, we show that OCT can perform in vivo detection of cortex and differentiate normal and abnormal cortical anatomy. This OCT system in this study provided an axial resolution of 10~15μ m, the transverse resolution of the system is about 25 μm. OCT can provide cross-sectional images of cortical of adult rats in response to cerebral ischemia injury.We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the cerebral cortex structures and may offer a new tool for Possible neuroscience clinical applications.

  5. "Hyperglutamatergic cortico-striato-thalamo-cortical circuit" breaker drugs alleviate tics in a transgenic circuit model of Tourette׳s syndrome.

    Science.gov (United States)

    Nordstrom, Eric J; Bittner, Katie C; McGrath, Michael J; Parks, Clinton R; Burton, Frank H

    2015-12-10

    The brain circuits underlying tics in Tourette׳s syndrome (TS) are unknown but thought to involve cortico/amygdalo-striato-thalamo-cortical (CSTC) loop hyperactivity. We previously engineered a transgenic mouse "circuit model" of TS by expressing an artificial neuropotentiating transgene (encoding the cAMP-elevating, intracellular A1 subunit of cholera toxin) within a small population of dopamine D1 receptor-expressing somatosensory cortical and limbic neurons that hyperactivate cortico/amygdalostriatal glutamatergic output circuits thought to be hyperactive in TS and comorbid obsessive-compulsive (OC) disorders. As in TS, these D1CT-7 ("Ticcy") transgenic mice׳s tics were alleviated by the TS drugs clonidine and dopamine D2 receptor antagonists; and their chronic glutamate-excited striatal motor output was unbalanced toward hyperactivity of the motoric direct pathway and inactivity of the cataleptic indirect pathway. Here we have examined whether these mice׳s tics are countered by drugs that "break" sequential elements of their hyperactive cortical/amygdalar glutamatergic and efferent striatal circuit: anti-serotonoceptive and anti-noradrenoceptive corticostriatal glutamate output blockers (the serotonin 5-HT2a,c receptor antagonist ritanserin and the NE alpha-1 receptor antagonist prazosin); agmatinergic striatothalamic GABA output blockers (the presynaptic agmatine/imidazoline I1 receptor agonist moxonidine); and nigrostriatal dopamine output blockers (the presynaptic D2 receptor agonist bromocriptine). Each drug class alleviates tics in the Ticcy mice, suggesting a hyperglutamatergic CSTC "tic circuit" could exist in TS wherein cortical/amygdalar pyramidal projection neurons׳ glutamatergic overexcitation of both striatal output neurons and nigrostriatal dopaminergic modulatory neurons unbalances their circuit integration to excite striatothalamic output and create tics, and illuminating new TS drug strategies.

  6. Ultrastructure of focal cerebral cortex tissue from rats with focal cortical dysplasia

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    BACKGROUND:Developing a model of focal cortical dysplasia in microgyrus and observing the ultrastructure of focal tissue is of important significance for analyzing the pathology of cortical developmental disorder and the factors of structural changes. OBJECTIVE:This study was to observe the pathological characteristics of focal tissue around the microgyrus of rats with cortical developmental disorder using an electron microscope,so as to analyze the causes associated with cerebral cortical developmental disorder. DESIGN:A randomized controlled animal experiment. SETTING:The First Affiliated Hospital of Chongqing Medical University. MATERIALS:This study was carried out in the Chongqing Key Laboratory of Neurology,Room for Electron Microscope of Chongqing Medical University,and Laboratory Animal Center,Research Institute of Surgery,Daping Hospital,Third Military Medical University of Chinese PLA between January 2004 and August 2006.Eighteen healthy newborn male Wistar rats,weighing 3.0 - 6.0 g,provided by the Laboratory Animal Center,Daping Hospital,Third Military Medical University of Chinese PLA,were involved in this study.The protocol was carried out in accordance with animal ethics guidelines for the use and care of animals.Probes (Chongqing Wire & Cable Factory,China) were made of copper core wire with diameter of 1 mm.METHODS:The rats were randomly divided into 3 groups with 6 in each:normal control group,liquid nitrogen injured group and sham-operation group.①In the liquid nitrogen injured group,a blunt probe frozen by liquid nitrogen was placed on fronto-parietal crinial bone of rats for 8 s.A 3 - 5 cm of microgyrus was induced in the unilateral cerebral sensory cortical area.In the sham-operation group,probe was placed at the room temperature.In the normal control group,rats were untouched.② The conscious state and electrical activity of brain of rats in each group were observed.③ 2-3 mm thickness of hippocampal tissue with coronary section was taken

  7. Homocysteine Aggravates Cortical Neural Cell Injury through Neuronal Autophagy Overactivation following Rat Cerebral Ischemia-Reperfusion

    Directory of Open Access Journals (Sweden)

    Yaqian Zhao

    2016-07-01

    Full Text Available Elevated homocysteine (Hcy levels have been reported to be involved in neurotoxicity after ischemic stroke. However, the underlying mechanisms remain incompletely understood to date. In the current study, we hypothesized that neuronal autophagy activation may be involved in the toxic effect of Hcy on cortical neurons following cerebral ischemia. Brain cell injury was determined by hematoxylin-eosin (HE staining and TdT-mediated dUTP Nick-End Labeling (TUNEL staining. The level and localization of autophagy were detected by transmission electron microscopy, western blot and immunofluorescence double labeling. The oxidative DNA damage was revealed by immunofluorescence of 8-Hydroxy-2′-deoxyguanosine (8-OHdG. Hcy treatment aggravated neuronal cell death, significantly increased the formation of autophagosomes and the expression of LC3B and Beclin-1 in the brain cortex after middle cerebral artery occlusion-reperfusion (MCAO. Immunofluorescence analysis of LC3B and Beclin-1 distribution indicated that their expression occurred mainly in neurons (NeuN-positive and hardly in astrocytes (GFAP-positive. 8-OHdG expression was also increased in the ischemic cortex of Hcy-treated animals. Conversely, LC3B and Beclin-1 overexpression and autophagosome accumulation caused by Hcy were partially blocked by the autophagy inhibitor 3-methyladenine (3-MA. Hcy administration enhanced neuronal autophagy, which contributes to cell death following cerebral ischemia. The oxidative damage-mediated autophagy may be a molecular mechanism underlying neuronal cell toxicity of elevated Hcy level.

  8. Plasticity during Sleep Is Linked to Specific Regulation of Cortical Circuit Activity

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    Niels Niethard

    2017-09-01

    Full Text Available Sleep is thought to be involved in the regulation of synaptic plasticity in two ways: by enhancing local plastic processes underlying the consolidation of specific memories and by supporting global synaptic homeostasis. Here, we briefly summarize recent structural and functional studies examining sleep-associated changes in synaptic morphology and neural excitability. These studies point to a global down-scaling of synaptic strength across sleep while a subset of synapses increases in strength. Similarly, neuronal excitability on average decreases across sleep, whereas subsets of neurons increase firing rates across sleep. Whether synapse formation and excitability is down or upregulated across sleep appears to partly depend on the cell’s activity level during wakefulness. Processes of memory-specific upregulation of synapse formation and excitability are observed during slow wave sleep (SWS, whereas global downregulation resulting in elimination of synapses and decreased neural firing is linked to rapid eye movement sleep (REM sleep. Studies of the excitation/inhibition balance in cortical circuits suggest that both processes are connected to a specific inhibitory regulation of cortical principal neurons, characterized by an enhanced perisomatic inhibition via parvalbumin positive (PV+ cells, together with a release from dendritic inhibition by somatostatin positive (SOM+ cells. Such shift towards increased perisomatic inhibition of principal cells appears to be a general motif which underlies the plastic synaptic changes observed during sleep, regardless of whether towards up or downregulation.

  9. Integration of gray matter nodules into functional cortical circuits in periventricular heterotopia

    Science.gov (United States)

    Christodoulou, Joanna A.; Barnard, Mollie E.; Del Tufo, Stephanie N.; Katzir, Tami; Whitfield-Gabrieli, Susan; Gabrieli, John D.E.; Chang, Bernard S.

    2013-01-01

    Alterations in neuronal circuitry are recognized as an important substrate of many neurological disorders, including epilepsy. Patients with the developmental brain malformation of periventricular nodular heterotopia (PNH) often have both seizures and dyslexia, and there is evidence to suggest that aberrant neuronal connectivity underlies both of these clinical features. We used task-based functional MRI (fMRI) to determine whether heterotopic nodules of gray matter in this condition are integrated into functional cortical circuits. Blood oxygenation level-dependent (BOLD) fMRI was acquired in eight participants with PNH during the performance of reading-related tasks. Evidence of neural activation within heterotopic gray matter was identified, and regions of cortical co-activation were then mapped systematically. Findings were correlated with resting-state functional connectivity results and with performance on the fMRI reading-related tasks. Six participants (75%) demonstrated activation within at least one region of gray matter heterotopia. Cortical areas directly overlying the heterotopia were usually co-activated (60%), as were areas known to have functional connectivity to the heterotopia in the task-free resting state (73%). Six of seven (86%) primary task contrasts resulted in heterotopia activation in at least one participant. Activation was most commonly seen during rapid naming of visual stimuli, a characteristic impairment in this patient population. Our findings represent a systematic demonstration that heterotopic gray matter can be metabolically coactivated in a neuronal migration disorder associated with epilepsy and dyslexia. Gray matter nodules were most commonly coactivated with anatomically overlying cortex and other regions with resting-state connectivity to heterotopia. These results have broader implications for understanding the network pathogenesis of both seizures and reading disabilities. PMID:24090774

  10. Cerebral causes and consequences of parkinsonian resting tremor: a tale of two circuits?

    Science.gov (United States)

    Helmich, Rick C; Hallett, Mark; Deuschl, Günther; Toni, Ivan; Bloem, Bastiaan R

    2012-11-01

    Tremor in Parkinson's disease has several mysterious features. Clinically, tremor is seen in only three out of four patients with Parkinson's disease, and tremor-dominant patients generally follow a more benign disease course than non-tremor patients. Pathophysiologically, tremor is linked to altered activity in not one, but two distinct circuits: the basal ganglia, which are primarily affected by dopamine depletion in Parkinson's disease, and the cerebello-thalamo-cortical circuit, which is also involved in many other tremors. The purpose of this review is to integrate these clinical and pathophysiological features of tremor in Parkinson's disease. We first describe clinical and pathological differences between tremor-dominant and non-tremor Parkinson's disease subtypes, and then summarize recent studies on the pathophysiology of tremor. We also discuss a newly proposed 'dimmer-switch model' that explains tremor as resulting from the combined actions of two circuits: the basal ganglia that trigger tremor episodes and the cerebello-thalamo-cortical circuit that produces the tremor. Finally, we address several important open questions: why resting tremor stops during voluntary movements, why it has a variable response to dopaminergic treatment, why it indicates a benign Parkinson's disease subtype and why its expression decreases with disease progression.

  11. Trading speed and accuracy by coding time: a coupled-circuit cortical model.

    Directory of Open Access Journals (Sweden)

    Dominic Standage

    2013-04-01

    Full Text Available Our actions take place in space and time, but despite the role of time in decision theory and the growing acknowledgement that the encoding of time is crucial to behaviour, few studies have considered the interactions between neural codes for objects in space and for elapsed time during perceptual decisions. The speed-accuracy trade-off (SAT provides a window into spatiotemporal interactions. Our hypothesis is that temporal coding determines the rate at which spatial evidence is integrated, controlling the SAT by gain modulation. Here, we propose that local cortical circuits are inherently suited to the relevant spatial and temporal coding. In simulations of an interval estimation task, we use a generic local-circuit model to encode time by 'climbing' activity, seen in cortex during tasks with a timing requirement. The model is a network of simulated pyramidal cells and inhibitory interneurons, connected by conductance synapses. A simple learning rule enables the network to quickly produce new interval estimates, which show signature characteristics of estimates by experimental subjects. Analysis of network dynamics formally characterizes this generic, local-circuit timing mechanism. In simulations of a perceptual decision task, we couple two such networks. Network function is determined only by spatial selectivity and NMDA receptor conductance strength; all other parameters are identical. To trade speed and accuracy, the timing network simply learns longer or shorter intervals, driving the rate of downstream decision processing by spatially non-selective input, an established form of gain modulation. Like the timing network's interval estimates, decision times show signature characteristics of those by experimental subjects. Overall, we propose, demonstrate and analyse a generic mechanism for timing, a generic mechanism for modulation of decision processing by temporal codes, and we make predictions for experimental verification.

  12. Analysing coupling architecture in the cortical EEG of a patient with unilateral cerebral palsy

    Science.gov (United States)

    Kornilov, Maksim V.; Baas, C. Marjolein; van Rijn, Clementina M.; Sysoev, Ilya V.

    2016-04-01

    The detection of coupling presence and direction between cortical areas from the EEG is a popular approach in neuroscience. Granger causality method is promising for this task, since it allows to operate with short time series and to detect nonlinear coupling or coupling between nonlinear systems. In this study EEG multichannel data from adolescent children, suffering from unilateral cerebral palsy were investigated. Signals, obtained in rest and during motor activity of affected and less affected hand, were analysed. The changes in inter-hemispheric and intra-hemispheric interactions were studied over time with an interval of two months. The obtained results of coupling were tested for significance using surrogate times series. In the present proceeding paper we report the data of one patient. The modified nonlinear Granger causality is indeed able to reveal couplings within the human brain.

  13. EFFECT OF MELATONIN AGAINST GLUTAMATE-INDUCED EXCITOTOXICITY ON CULTURED CEREBRAL CORTICAL NEURONS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective To research the effect of melatonin against glutamate excitotoxicity. Methods The model of glutamate-induced excitotoxic damage was built up in rat cerebral cortical cell culture. The effect of mela- tonin against excitotoxic injury was observed by determining the leakage rate of lactate dehydrogenase(LDH) from neurons. Results The leakage rate of LDH wasn't decreased markedly when cultures were exposed to melatonin be- fore, during or 6 h after glutamate treatment. The leakage rate of LDH was decreased significantly when melatonin was administered 0 h, 2 h or 4 h after the cultures were exposed to glutamate. The inhibitory function of melatonin on LDH leakage was most effective at 2 h and 4 h. Conclusion Melatonin has protective effects on neurons damaged by glutamate in a certain time limit.

  14. Tissue-type plasminogen activator induces synaptic vesicle endocytosis in cerebral cortical neurons.

    Science.gov (United States)

    Yepes, M; Wu, F; Torre, E; Cuellar-Giraldo, D; Jia, D; Cheng, L

    2016-04-05

    The release of the serine proteinase tissue-type plasminogen activator (tPA) from the presynaptic terminal of cerebral cortical neurons plays a central role in the development of synaptic plasticity, adaptation to metabolic stress and neuronal survival. Our earlier studies indicate that by inducing the recruitment of the cytoskeletal protein βII-spectrin and voltage-gated calcium channels to the active zone, tPA promotes Ca(2+)-dependent translocation of synaptic vesicles (SVs) to the synaptic release site where they release their load of neurotransmitters into the synaptic cleft. Here we used a combination of in vivo and in vitro experiments to investigate whether this effect leads to depletion of SVs in the presynaptic terminal. Our data indicate that tPA promotes SV endocytosis via a mechanism that does not require the conversion of plasminogen into plasmin. Instead, we show that tPA induces calcineurin-mediated dynamin I dephosphorylation, which is followed by dynamin I-induced recruitment of the actin-binding protein profilin II to the presynaptic membrane, and profilin II-induced F-actin formation. We report that this tPA-induced sequence of events leads to the association of newly formed SVs with F-actin clusters in the endocytic zone. In summary, the data presented here indicate that following the exocytotic release of neurotransmitters tPA activates the mechanism whereby SVs are retrieved from the presynaptic membrane and endocytosed to replenish the pool of vesicles available for a new cycle of exocytosis. Together, these results indicate that in murine cerebral cortical neurons tPA plays a central role coupling SVs exocytosis and endocytosis.

  15. Disentangling How the Brain is "Wired" in Cortical (Cerebral) Visual Impairment.

    Science.gov (United States)

    Merabet, Lotfi B; Mayer, D Luisa; Bauer, Corinna M; Wright, Darick; Kran, Barry S

    2017-05-01

    Cortical (cerebral) visual impairment (CVI) results from perinatal injury to visual processing structures and pathways of the brain and is the most common cause of severe visual impairment or blindness in children in developed countries. Children with CVI display a wide range of visual deficits including decreased visual acuity, impaired visual field function, as well as impairments in higher-order visual processing and attention. Together, these visual impairments can dramatically influence a child's development and well-being. Given the complex neurologic underpinnings of this condition, CVI is often undiagnosed by eye care practitioners. Furthermore, the neurophysiological basis of CVI in relation to observed visual processing deficits remains poorly understood. Here, we present some of the challenges associated with the clinical assessment and management of individuals with CVI. We discuss how advances in brain imaging are likely to help uncover the underlying neurophysiology of this condition. In particular, we demonstrate how structural and functional neuroimaging approaches can help gain insight into abnormalities of white matter connectivity and cortical activation patterns, respectively. Establishing a connection between how changes within the brain relate to visual impairments in CVI will be important for developing effective rehabilitative and education strategies for individuals living with this condition. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. HIV-Associated Distal Neuropathic Pain is Associated with Smaller Total Cerebral Cortical Gray Matter

    Science.gov (United States)

    Keltner, John R.; Fennema-Notestine, Christine; Vaida, Florin; Wang, Dongzhe; Franklin, Donald R.; Dworkin, Robert H.; Sanders, Chelsea; McCutchan, J. Allen; Archibald, Sarah L.; Miller, David J.; Kesidis, George; Cushman, Clint; Kim, Sung Min; Abramson, Ian; Taylor, Michael J.; Theilmann, Rebecca J.; Julaton, Michelle D.; Notestine, Randy J.; Corkran, Stephanie; Cherner, Mariana; Duarte, Nichole A.; Alexander, Terry; Robinson-Papp, Jessica; Gelman, Benjamin B.; Simpson, David M.; Collier, Ann C.; Marra, Christina M.; Morgello, Susan; Brown, Greg; Grant, Igor; Atkinson, J. Hampton; Jernigan, Terry L.; Ellis, Ronald J.

    2014-01-01

    Despite modern antiretroviral therapy, HIV-associated sensory neuropathy affects over 50% of HIV patients. The clinical expression of HIV neuropathy is highly variable: many individuals report few symptoms, but about half report distal neuropathic pain (DNP), making it one of the most prevalent, disabling and treatment-resistant complications of HIV disease. The presence and intensity of pain is not fully explained by the degree of peripheral nerve damage, making it unclear why some patients do, and others do not, report pain. To better understand central nervous system contributions to HIV DNP, we performed a cross-sectional analysis of structural magnetic resonance imaging (MRI) volumes in 241 HIV-infected participants from an observational multi-site cohort study at five US sites (CNS HIV Antiretroviral Treatment Effects Research Study, CHARTER). The association between DNP and the structural imaging outcomes was investigated using both linear and nonlinear (Gaussian Kernel support vector) multivariable regression, controlling for key demographic and clinical variables. Severity of DNP symptoms was correlated with smaller total cerebral cortical gray matter volume (R = −0.24; p = 0.004). Understanding the mechanisms for this association between smaller total cortical volumes and DNP may provide insight into HIV DNP chronicity and treatment-resistance. PMID:24549970

  17. Spatio-temporal cerebral blood flow perfusion patterns in cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Yu.; Verveyko, Darya V.; Postnov, Dmitry E.

    2017-04-01

    Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

  18. HIV-associated distal neuropathic pain is associated with smaller total cerebral cortical gray matter.

    Science.gov (United States)

    Keltner, John R; Fennema-Notestine, Christine; Vaida, Florin; Wang, Dongzhe; Franklin, Donald R; Dworkin, Robert H; Sanders, Chelsea; McCutchan, J Allen; Archibald, Sarah L; Miller, David J; Kesidis, George; Cushman, Clint; Kim, Sung Min; Abramson, Ian; Taylor, Michael J; Theilmann, Rebecca J; Julaton, Michelle D; Notestine, Randy J; Corkran, Stephanie; Cherner, Mariana; Duarte, Nichole A; Alexander, Terry; Robinson-Papp, Jessica; Gelman, Benjamin B; Simpson, David M; Collier, Ann C; Marra, Christina M; Morgello, Susan; Brown, Greg; Grant, Igor; Atkinson, J Hampton; Jernigan, Terry L; Ellis, Ronald J

    2014-06-01

    Despite modern antiretroviral therapy, HIV-associated sensory neuropathy affects over 50 % of HIV patients. The clinical expression of HIV neuropathy is highly variable: many individuals report few symptoms, but about half report distal neuropathic pain (DNP), making it one of the most prevalent, disabling, and treatment-resistant complications of HIV disease. The presence and intensity of pain is not fully explained by the degree of peripheral nerve damage, making it unclear why some patients do, and others do not, report pain. To better understand central nervous system contributions to HIV DNP, we performed a cross-sectional analysis of structural magnetic resonance imaging volumes in 241 HIV-infected participants from an observational multi-site cohort study at five US sites (CNS HIV Anti-Retroviral Treatment Effects Research Study, CHARTER). The association between DNP and the structural imaging outcomes was investigated using both linear and nonlinear (Gaussian Kernel support vector) multivariable regression, controlling for key demographic and clinical variables. Severity of DNP symptoms was correlated with smaller total cerebral cortical gray matter volume (r = -0.24; p = 0.004). Understanding the mechanisms for this association between smaller total cortical volumes and DNP may provide insight into HIV DNP chronicity and treatment-resistance.

  19. Morphine enhances the release of /sup 3/H-purines from rat brain cerebral cortical prisms

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.H.; Phillis, J.W.; Yuen, H.

    1982-10-01

    In vitro experiments have shown that /sup 3/H-purines can be released from /sup 3/H-adenosine preloaded rat brain cortical prisms by a KCl-evoked depolarization. The KCl-evoked release of /sup 3/H-purines is dependent on the concentration of KCl present in the superfusate. At concentrations of 10(-7) approximately 10(-5)M morphine did not influence the basal release of /sup 3/H-purines from the prisms, although it enhanced the KCl-evoked release of /sup 3/H-purines. The enhancement of KCl-evoked /sup 3/H-purine release by morphine was concentration-dependent and was antagonized by naloxone, suggesting the involvement of opiate receptors. Uptake studies with rat brain cerebral cortical synaptosomes show that morphine is a very weak inhibitor of adenosine uptake. Comparisons with dipyridamole, a potent inhibitor of adenosine uptake, suggest that this low level of inhibition of the uptake did not contribute significantly to the release of /sup 3/H-purine by morphine seen in our experiments. It is therefore suggested that morphine enhances KCl-evoked /sup 3/H-purine release by an interaction with opiate receptors and that the resultant increase in extracellular purine (adenosine) levels may account for some of the actions of morphine.

  20. Early magnetic resonance detection of cortical necrosis and acute network injury associated with neonatal and infantile cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Okabe, Tetsuhiko; Aida, Noriko; Nozawa, Kumiko [Kanagawa Children' s Medical Center, Department of Radiology, Yokohama (Japan); Niwa, Tetsu [Kanagawa Children' s Medical Center, Department of Radiology, Yokohama (Japan); Tokai University School of Medicine, Department of Radiology, Isehara (Japan); Shibasaki, Jun [Kanagawa Children' s Medical Center, Department of Neonatology, Yokohama (Japan); Osaka, Hitoshi [Kanagawa Children' s Medical Center, Department of Neurology, Yokohama (Japan)

    2014-05-15

    Knowledge of MRI findings in pediatric cerebral infarction is limited. To determine whether cortical necrosis and network injury appear in the acute phase in post-stroke children and to identify anatomical location of acute network injury and the ages at which these phenomena are seen. Images from 12 children (age range: 0-9 years; neonates [<1 month], n=5; infants [1 month-12 months], n=3; others [≥1 year], n=4) with acute middle cerebral artery (MCA) cortical infarction were retrospectively analyzed. Cortical necrosis was defined as hyperintense cortical lesions on T1-weighted imaging that lacked evidence of hemorrhage. Acute network injury was defined as hyperintense lesions on diffusion-weighted imaging that were not in the MCA territory and had fiber connections with the affected cerebral cortex. MRI was performed within the first week after disease onset. Cortical necrosis was only found in three neonates. Acute network injury was seen in the corticospinal tract (CST), thalamus and corpus callosum. Acute network injury along the CST was found in five neonates and one 7-month-old infant. Acute network injury was evident in the thalamus of four neonates and two infants (ages 4 and 7 months) and in the corpus callosum of five neonates and two infants (ages 4 and 7 months). The entire thalamus was involved in three children when infarction of MCA was complete. In acute MCA cortical infarction, MRI findings indicating cortical necrosis or acute network injury was frequently found in neonates and early infants. Response to injury in a developing brain may be faster than that in a mature one. (orig.)

  1. Increased 20-HETE synthesis explains reduced cerebral blood flow but not impaired neurovascular coupling after cortical spreading depression in rat cerebral cortex

    DEFF Research Database (Denmark)

    Fordsmann, Jonas Christoffer; ko, Rebecca; Choi, Hyun B

    2013-01-01

    Cortical spreading depression (CSD) is associated with release of arachidonic acid (AA), impaired neurovascular coupling, and reduced cerebral blood flow (CBF), caused by cortical vasoconstriction. We tested the hypothesis that the released AA is metabolized by the cytochrome P450 enzyme to produce...... neurovascular coupling after CSD. These findings suggest that CSD-induced increments in 20-HETE cause the reduction in CBF after CSD, and that the attenuation of stimulation-induced CBF responses after CSD has a different mechanism. We suggest that blockade of 20-HETE synthesis may be clinically relevant...

  2. Apoptosis is not an invariable component of in vitro models of cortical cerebral ischaemia

    Institute of Scientific and Technical Information of China (English)

    Paul Alexander JONES; Gillian Ruth MAY; Joyce Ann MCLUCKIE; Akinori IWASHITA; John SHARKEY

    2004-01-01

    Characterising the mechanisms of cell death following focal cerebral ischaemia has been hampered by a lack of an in vitro assay emulating both the apoptotic and necrotic features observed in vivo. The present study systematically characterised oxygen-glucose-deprivation (OGD) in primary rat cortical neurones to establish a reproducible model with components of both cell-death endpoints. OGD induced a time-dependent reduction in cell viability, with 80% cell death occurring 24 h after 3 h exposure to 0% O2 and 0.5 mM glucose. Indicative of a necrotic component to OGDinduced cell death, N-methyl-D-aspartate (NMDA) receptor inhibition with MK-801 attenuated neuronal loss by 60%.The lack of protection by the caspase inhibitors DEVD-CHO and z-VAD-fmk suggested that under these conditions neurones did not die by an apoptotic mechanism. Moderating the severity of the insult by decreasing OGD exposure to 60 min did not reduce the amount of necrosis, but did induce a small degree of apoptosis (a slight reduction in cell death was observed in the presence of 10 μtM DEVD-CHO). In separate experiments purported to enhance the apoptotic component, cells were gradually deprived of O2, exposed to 4% O2 (as opposed to 0%) during the OGD period, or maintained in serum-containing media throughout. While NMDA receptor antagonism significantly reduced cortical cell death under all conditions, a caspase-inhibitor sensitive component of cell death was not uncovered. These studies suggest that OGD of cultured cortical cells models the excitotoxic, but not the apoptotic component of cell death observed in vivo.

  3. Acetylcholine modulates transient outward potassium channel in acutely isolated cerebral cortical neurons of rats

    Institute of Scientific and Technical Information of China (English)

    Lanwei Cui; Tao Sun; Lihui Qu; Yurong Li; Haixia Wen

    2009-01-01

    BACKGROUND:The neuronal transient outward potassium channel has been shown to be highly associated with acetylcholine.However,the influence of acetylcholine on the transient outward potassium current in cerebral cortical neurons remains poorly understood.OBJECTIVE:To investigate acetylcholine modulation on transient outward potassium current in rat parietal cortical neurons using the whole-cell patch-clamp technique.DESIGN,TIME AND SETTING:A neuroelectrophysiology study was performed at the Department of Physiology,Harbin Medical University between January 2005 and January 2006.MATERIALS:Wistar rats were provided by the Animal Research Center,the Second Hospital of Harbin Medical University;PC-IIC patch-clamp amplifier and IBBClamp data collection analysis system were provided by Huazhong University for Science and Technology,Wuhan,China;PP-83 microelectrode puller was purchased from Narrishage,Japan.METHODS:The parietal somatosensory cortical neurons were acutely dissociated,and the modulation of acetylcholine (0.1,1,10,100 μmol/L) on transient outward potassium channel was recorded using the whole-cell patch-clamp technique.MAIN OUTCOME MEASURES:Influence of acetylcholine on transient outward potassium current,potassium channel activation,and inactivation.RESULTS:The inhibitory effect of acetylcholine on transient outward potassium current was dose- and voltage-dependent (P<0.01).Acetylcholine was found to significantly affect the activation process of transient outward potassium current,i.e.,the activation curve of transient outward potassium current was left-shifted,while the inactivation curve was shifted to hyperpolarization.Acetylcholine significantly prolonged the time constant of recovery from inactivation of transient outward potassium current (P<0.01).CONCLUSION:These results suggest that acetylcholine inhibits transient outward potassium current by regulating activation and inactivation processes of the transient outward potassium channel.

  4. Effects of the muscarinic antagonists pirenzepine and gallamine on spontaneous and evoked responses of rat cerebral cortical neurones.

    Science.gov (United States)

    Swanson, T. H.; Phillis, J. W.

    1988-01-01

    1. The muscarinic receptor antagonists gallamine and pirenzepine were iontophoretically applied to rat cerebral cortical cholinoceptive neurones, including corticospinal neurones, to assess their effects on spontaneous firing, and firing induced by: stimulation of the nucleus basalis magnocellularis (NBM); contralateral hindpaw stimulation; application of acetylcholine (ACh); and application of glutamate. 2. Both compounds potently inhibited firing induced by ACh iontophoresis, whilst neither compound consistently altered firing induced by application of glutamate. 3. Gallamine was very effective and pirenzepine less effective, at inhibiting both spontaneous firing and the delayed firing induced by NBM stimulation. The short-latency excitations elicited by NBM stimulation were enhanced by these muscarinic antagonists. 4. Gallamine and pirenzepine enhanced cortical cholinoceptive cell firing induced by contralateral hindpaw stimulation. 5. It is concluded that gallamine depresses spontaneous activity more than pirenzepine, and that both compounds can affect the cortical cell firing evoked by stimulation of the NBM and of thalamo-cortical afferent fibres. PMID:3401638

  5. Ultrastructural changes of rat cortical neurons following ligustrazine intervention for cerebral ischemia/reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Hui Zhang; Jianfeng Dong; Qiuzhen Zhao; Wen Song; Aihua Bo

    2008-01-01

    low-dose group and ligustrazine high-dose group received ligustrazine injections, 50 mg/kg and 100 mg/kg, respectively. Samples were collected at the same time as the model group.MAIN OUTCOME MEASURES: Alterations of the neuronal ultrastructure and main organelles were ob-served by electron microscopy.RESULTS: Forty Wistar rats were included in the final analysis. Plentiful ribosome and rough endoplasmic reticulum existed in the cytoplasm of cortical neurons in the normal group. Edema existed in the nucleus and cytoplasm of neurons in the model group. The cell membrane was damaged, resulting in the external erup-tion of certain cellular organelles. In the low-dose ligustrazine group, neuronal swelling was decreased in the cytoplasm, whereas cellular organelles were relatively increased. However, the mitochondria remained swollen. The double layer structure disappeared in parts of the mitochondrial membrane. The caryotheca was still broken, and neuronal damage was significantly decreased in the high-dose ligustrazine group. In ad-dition, cytoplasmic swelling was reduced andmost part of caryotheca was complete. Fragmentation of the cellular membrane was not detected. Mitochondrial cristae and the lysosome could also be detected. The number of rough endoplasmic reticulum and free ribosomes was increased, and the structure of great part of caryotheca was clear. In addition, the number of nuclear pore was increased. However, the nuclear hetero-chromatin was relatively reduced.CONCLUSION: In the rat, the protective effects of ligustrazine were significant on neuronal membrane structures and main organelles after cerebral ischemia/reperfusion. There was a dose-dependent effect be-tween neuronal changes and Ligustrazine.

  6. Functional states of rat cortical circuits during the unpredictable availability of a reward-related cue.

    Science.gov (United States)

    Fernández-Lamo, Iván; Sánchez-Campusano, Raudel; Gruart, Agnès; Delgado-García, José M

    2016-11-21

    Proper performance of acquired abilities can be disturbed by the unexpected occurrence of external changes. Rats trained with an operant conditioning task (to press a lever in order to obtain a food pellet) using a fixed-ratio (1:1) schedule were subsequently placed in a Skinner box in which the lever could be removed randomly. Field postsynaptic potentials (fPSPs) were chronically evoked in perforant pathway-hippocampal CA1 (PP-CA1), CA1-subiculum (CA1-SUB), CA1-medial prefrontal cortex (CA1-mPFC), mPFC-nucleus accumbens (mPFC-NAc), and mPFC-basolateral amygdala (mPFC-BLA) synapses during lever IN and lever OUT situations. While lever presses were accompanied by a significant increase in fPSP slopes at the five synapses, the unpredictable absence of the lever were accompanied by decreased fPSP slopes in all, except PP-CA1 synapses. Spectral analysis of local field potentials (LFPs) recorded when the animal approached the corresponding area in the lever OUT situation presented lower spectral powers than during lever IN occasions for all recording sites, apart from CA1. Thus, the unpredictable availability of a reward-related cue modified the activity of cortical and subcortical areas related with the acquisition of operant learning tasks, suggesting an immediate functional reorganization of these neural circuits to address the changed situation and to modify ongoing behaviors accordingly.

  7. Long-tailed distribution of synaptic strength reveals origin and functional roles of ongoing fluctuation in cortical circuit

    Science.gov (United States)

    Teramae, Jun-nosuke

    2016-06-01

    Neurons in the cortical circuit continuous to generate irregular spike firing with extremely low firing rate (about 1-2 Hz) even when animals neither receive any external stimuli nor they do not show any significant motor movement. The ongoing activity is often called neuronal noise because measured spike trains are often highly irregular and also spike timings are highly asynchronous among neurons. Many experiments imply that neural networks themselves must generate the noisy activity as an intrinsic property of cortical circuit. However, how a network of neurons sustains the irregular spike firings with low firing rate remains unclear. Recently, by focusing on long-tailed distribution of amplitude of synaptic connections or EPSP (Excitatory Post-Synaptic Potential), we successfully revealed that due to coexistence of a few extremely strong synaptic connections and majority of weak synapses, nonlinear dynamics of population of spiking neurons can have a nontrivial stable state that corresponding to the intrinsic ongoing fluctuation of the cortical circuit. We also found that due to the fluctuation fidelity of spike transmission between neurons are optimized. Here, we report our recent findings of the ongoing fluctuation from viewpoints of mathematical and computational side.

  8. ASPM and the evolution of cerebral cortical size in a community of New World monkeys.

    Directory of Open Access Journals (Sweden)

    Fernando A Villanea

    Full Text Available The ASPM (abnormal spindle-like microcephaly associated gene has been proposed as a major determinant of cerebral cortical size among primates, including humans. Yet the specific functions of ASPM and its connection to human intelligence remain controversial. This debate is limited in part by a taxonomic focus on Old World monkeys and apes. Here we expand the comparative context of ASPM sequence analyses with a study of New World monkeys, a radiation of primates in which enlarged brain size has evolved in parallel in spider monkeys (genus Ateles and capuchins (genus Cebus. The primate community of Costa Rica is perhaps a model system because it allows for independent pairwise comparisons of smaller- and larger-brained species within two taxonomic families. Accordingly, we analyzed the complete sequence of exon 18 of ASPM in Ateles geoffroyi, Alouatta palliata, Cebus capucinus, and Saimiri oerstedii. As the analysis of multiple species in a genus improves phylogenetic reconstruction, we also analyzed eleven published sequences from other New World monkeys. Our exon-wide, lineage-specific analysis of eleven genera and the ratio of rates of nonsynonymous to synonymous substitutions (d(N/d(S on ASPM revealed no detectable evidence for positive selection in the lineages leading to Ateles or Cebus, as indicated by d(N/d(S ratios of <1.0 (0.6502 and 0.4268, respectively. Our results suggest that a multitude of interacting genes have driven the evolution of larger brains among primates, with different genes involved in this process in different encephalized lineages, or at least with evidence for positive selection not readily apparent for the same genes in all lineages. The primate community of Costa Rica may serve as a model system for future studies that aim to elucidate the molecular mechanisms underlying cognitive capacity and cortical size.

  9. Children with cerebral palsy have uncharacteristic somatosensory cortical oscillations after stimulation of the hand mechanoreceptors.

    Science.gov (United States)

    Kurz, M J; Becker, K M; Heinrichs-Graham, E; Wilson, T W

    2015-10-01

    Numerous clinical investigations have reported that children with cerebral palsy (CP) have tactile discrimination deficits that likely limit their ability to plan and manipulate objects. Despite this clinical awareness, we still have a substantial knowledge gap in our understanding of the neurological basis for these tactile discrimination deficits. Previously, we have shown that children with CP have aberrant theta-alpha (4-14 Hz) oscillations in the somatosensory cortices following tactile stimulation of the foot. In this investigation, we evaluated if these aberrant theta-alpha oscillations also extend to the hand. Magnetoencephalography was used to evaluate event-related changes in the theta-alpha and beta (18-34 Hz) somatosensory cortical oscillations in groups of children with CP and typically developing (TD) children following tactile stimulation of their hands. Our results showed that the somatosensory theta-alpha oscillations were relatively intact in children with CP, which is in contrast to our previous results for foot tactile stimulations. We suspect that these inter-study differences may be related to the higher probability that the neural tracts serving the lower extremities are damaged in children with CP, compared to those serving the upper extremities. This inference is plausible since the participating children with CP had Manual Ability Classification System (MACS) levels between I and II. In contrast to the theta-alpha results, children with CP did exhibit a sharp increase in beta activity during the same time period, which was not observed in TD children. This suggests that children with CP still have deficits in the computational aspect of somatosensory processing.

  10. Quantitative comparison of cortical and deep grey matter in pathological subtypes of unilateral cerebral palsy.

    Science.gov (United States)

    Scheck, Simon M; Pannek, Kerstin; Fiori, Simona; Boyd, Roslyn N; Rose, Stephen E

    2014-10-01

    The aim of this study was to quantify grey matter changes in children with unilateral cerebral palsy (UCP), differentiating between cortical or deep grey matter (CDGM) lesions, periventricular white matter (PWM) lesions, and unilateral and bilateral lesions. In a cross-sectional study we obtained high resolution structural magnetic resonance images from 72 children (41 males, 31 females, mean age 10y 9mo [SD 3y 1mo], range 5y 1mo-17y 1mo) with UCP (33 left, 39 right hemiplegia; Manual Ability Classification System level I n=29, II n=43; Gross Motor Function Classification System level I n=46, II n=26), and 19 children with typical development (CTD; eight males, 11 females, mean age 11y 2mo [SD 2y 7mo], range 7y 8mo-16y 4mo). Images were classified by lesion type and analyzed using voxel-based morphometry (VBM) and subcortical volumetric analysis. Deep grey matter volumes were not significantly different between children with CDGM and PWM lesions, with the thalamus, putamen, and globus pallidus being reduced unilaterally in both groups compared with CTD (p≤0.001). Children with CDGM lesions additionally showed widespread cortical changes involving all lobes using VBM (p<0.01). Children with bilateral lesions had reduced thalamus and putamen volumes bilaterally (p<0.001). The thalamic volume was reduced bilaterally in children with unilateral lesions (p=0.004). Lesions to the PWM cause secondary changes to the deep grey matter structures similar to primary changes seen in CDGM lesions. Despite having a unilateral phenotype, grey matter changes are observed bilaterally, even in children with unilateral lesions. © 2014 Mac Keith Press.

  11. CT and MR Studies of Giant Dermoid Cyst Associated to Fat Dissemination at the Cortical and Cisternal Cerebral Spaces

    Directory of Open Access Journals (Sweden)

    Alessandro D'Amore

    2013-01-01

    Full Text Available This study focuses on CT and MR studies of adult patient with giant lesion of the posterior cranial fossa associated with micro- and macroaccumulations with density and signal like “fat” at the level of the cortical and cisternal cerebral spaces. This condition is compatible with previous asymptomatic ruptured dermoid cyst. Histological findings confirm the hypothesis formulated using the imaging. We also integrate elements of differential diagnosis by another giant lesion of the posterior cranial fossa.

  12. A common cortical circuit mechanism for perceptual categorical discrimination and veridical judgment.

    Directory of Open Access Journals (Sweden)

    Feng Liu

    2008-12-01

    Full Text Available Perception involves two types of decisions about the sensory world: identification of stimulus features as analog quantities, or discrimination of the same stimulus features among a set of discrete alternatives. Veridical judgment and categorical discrimination have traditionally been conceptualized as two distinct computational problems. Here, we found that these two types of decision making can be subserved by a shared cortical circuit mechanism. We used a continuous recurrent network model to simulate two monkey experiments in which subjects were required to make either a two-alternative forced choice or a veridical judgment about the direction of random-dot motion. The model network is endowed with a continuum of bell-shaped population activity patterns, each representing a possible motion direction. Slow recurrent excitation underlies accumulation of sensory evidence, and its interplay with strong recurrent inhibition leads to decision behaviors. The model reproduced the monkey's performance as well as single-neuron activity in the categorical discrimination task. Furthermore, we examined how direction identification is determined by a combination of sensory stimulation and microstimulation. Using a population-vector measure, we found that direction judgments instantiate winner-take-all (with the population vector coinciding with either the coherent motion direction or the electrically elicited motion direction when two stimuli are far apart, or vector averaging (with the population vector falling between the two directions when two stimuli are close to each other. Interestingly, for a broad range of intermediate angular distances between the two stimuli, the network displays a mixed strategy in the sense that direction estimates are stochastically produced by winner-take-all on some trials and by vector averaging on the other trials, a model prediction that is experimentally testable. This work thus lends support to a common neurodynamic

  13. Relaxation from a voluntary contraction is preceded by increased excitability of motor cortical inhibitory circuits.

    Science.gov (United States)

    Buccolieri, Alessandro; Abbruzzese, Giovanni; Rothwell, John C

    2004-07-15

    Termination of a muscle contraction is as important a part of movement as muscle activation yet the mechanisms responsible are less well understood. In the present experiments we examined the possible role of intracortical inhibitory circuits in terminating a 20% maximum isometric contraction of the first dorsal interosseous muscle (FDI) in eight healthy subjects. Subjects performed the task simultaneously with both hands and received single or pairs (at an interstimulus interval of 3 ms to evaluate short interval intracortical inhibition, SICI) of transcranial magnetic stimuli (TMS) via a focal coil over the motor hand area of the left hemisphere at different times before and after the onset of relaxation. The amplitude of the motor-evoked potential (MEP) following a single or a pair of TMS pulses was measured in the right FDI and plotted relative to the onset of relaxation as estimated from the surface electromyogram (EMG) of the left FDI. MEPs were larger during contraction than after relaxation whereas SICI was absent during contraction and reappeared after relaxation. We found that in all subjects, the time course of MEP changes during relaxation was closely fitted by a Boltzmann sigmoidal curve which allowed us to estimate the mean MEP amplitudes as well as the ratio of the amplitudes after single or pairs of TMS pulses (i.e.%SICI) at any time in the task. The data showed that the amplitude of MEPs to single pulse TMS had started to decline at about the same time as the onset of EMG silence. Furthermore, the size of the MEPs evoked by paired pulses decreased up to 30 ms beforehand. The latter suggests that an increase in SICI occurs prior to the onset of MEP changes, and hence that increased cortical inhibition may play a role in suppressing corticospinal excitability during relaxation. A subsidiary experiment showed that the time relations of changes in SICI and MEP were unchanged by a period of 10 min training on the task.

  14. Computational model of cerebral blood flow redistribution during cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Y.; Verveyko, Darya V.; Postnov, Dmitry E.

    2016-04-01

    In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem. In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.

  15. Effects of Cortical Spreading Depression on Synaptic Activity, Blood Flow and Oxygen Consumption in Rat Cerebral Cortex

    DEFF Research Database (Denmark)

    Hansen, Henning Piilgaard

    2010-01-01

    As the title of this thesis indicates I have during my PhD studied the effects of cortical spreading depression (CSD) on synaptic activity, blood flow and oxygen consumption in rat cerebral cortex. This was performed in vivo using an open cranial window approach in anesthetized rats. I applied...... two different sets of interneurons. Our data imply that for a given cortical area the amplitude of vascular signals will depend critically on the type of input and hence on the type of neurons activated. In the second study I investigated the effect of cortical spreading depression (CSD) on the evoked...... of neurovascular coupling after topical pretreatment with either inhibitor of CaN pathway (FK506), inhibitor of mPTP formation (NIM811) and combined inhibition of both pathways (FK506+NIM811 or cyclosporin A). A result indicating a potential new treatment aspect for disease states where CSD is known to be involved...

  16. 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).

  17. Atypical form of Alzheimer's disease with prominent posterior cortical atrophy: a review of lesion distribution and circuit disconnection in cortical visual pathways

    Science.gov (United States)

    Hof, P. R.; Vogt, B. A.; Bouras, C.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1997-01-01

    In recent years, the existence of visual variants of Alzheimer's disease characterized by atypical clinical presentation at onset has been increasingly recognized. In many of these cases post-mortem neuropathological assessment revealed that correlations could be established between clinical symptoms and the distribution of neurodegenerative lesions. We have analyzed a series of Alzheimer's disease patients presenting with prominent visual symptomatology as a cardinal sign of the disease. In these cases, a shift in the distribution of pathological lesions was observed such that the primary visual areas and certain visual association areas within the occipito-parieto-temporal junction and posterior cingulate cortex had very high densities of lesions, whereas the prefrontal cortex had fewer lesions than usually observed in Alzheimer's disease. Previous quantitative analyses have demonstrated that in Alzheimer's disease, primary sensory and motor cortical areas are less damaged than the multimodal association areas of the frontal and temporal lobes, as indicated by the laminar and regional distribution patterns of neurofibrillary tangles and senile plaques. The distribution of pathological lesions in the cerebral cortex of Alzheimer's disease cases with visual symptomatology revealed that specific visual association pathways were disrupted, whereas these particular connections are likely to be affected to a less severe degree in the more common form of Alzheimer's disease. These data suggest that in some cases with visual variants of Alzheimer's disease, the neurological symptomatology may be related to the loss of certain components of the cortical visual pathways, as reflected by the particular distribution of the neuropathological markers of the disease.

  18. Cortical somatosensory reorganization in children with spastic cerebral palsy: a multimodal neuroimaging study

    Directory of Open Access Journals (Sweden)

    CHRISTOS ePAPADELIS

    2014-09-01

    Full Text Available Although cerebral palsy (CP is among the most common causes of physical disability in early childhood, we know little about the functional and structural changes of this disorder in the developing brain. Here, we investigated with three different neuroimaging modalities (magnetoencephalography (MEG, diffusion tension imaging (DTI, and resting state fMRI whether spastic CP is associated with functional and anatomical abnormalities in the sensorimotor network. Ten children participated in the study: four with diplegic CP (DCP, three with hemiplegic CP (HCP, and three typically-developing (TD children. Somatosensory evoked fields (SEFs were recorded in response to pneumatic stimuli applied to digits D1, D3, and D5 of both hands. Several parameters of water diffusion were calculated from DTI between the thalamus and the precentral and postcentral gyri in both hemispheres. The sensorimotor resting state networks (RSNs were examined by using an independent component analysis method. Tactile stimulation of the fingers elicited the first prominent cortical response at ~50 ms, in all except one child, localized over the primary somatosensory cortex (S1. In five CP children, abnormal somatotopic organization was observed in the affected (or more affected hemisphere. Euclidean distances were markedly different between the two hemispheres in the HCP children, and between DCP and TD children for both hemispheres. DTI analysis revealed decreased fractional anisotropy and increased apparent diffusion coefficient for the thalamocortical pathways in the more affected compared to less affected hemisphere in CP children. Rs-fMRI results indicated absent and/or abnormal sensorimotor RSNs for children with HCP and DCP consistent with the severity and location of their lesions. Our findings suggest an abnormal somatosensory processing mechanism in the sensorimotor network of children with CP possibly as a result of diminished thalamocortical projections.

  19. Regional vulnerability of longitudinal cortical association connectivity: Associated with structural network topology alterations in preterm children with cerebral palsy.

    Science.gov (United States)

    Ceschin, Rafael; Lee, Vince K; Schmithorst, Vince; Panigrahy, Ashok

    2015-01-01

    Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL), are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI) studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4) and 75 healthy controls (mean age 5.7 ± 3.4). Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS) and voxel-based morphometry (VBM) demonstrating diffusely reduced fractional anisotropy (FA) reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1) reduced regional posterior-anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation) correlated with reduced posterior-anterior gradient of intra-regional (nodal efficiency) metrics with relative sparing of frontal and temporal regions; and (2) reduced regional FA within frontal-thalamic-striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract) correlated with

  20. Effects of acupoint versus non-acupoint electroacupuncture on cerebral cortical neuronal Bcl-2,Bax and caspase-3 expression in a rat model of focal cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Jun Wang; Junming Fan; Yongshu Dong; Xia Huang; Hongxia Zhang

    2008-01-01

    BACKGROUND: Several studies have demonstrated that electroacupuncture by acupoint selection can inhibit cerebral cortical neuronal apoptosis following cerebral ischemia/reperfusion.OBJECTIVE: To validate the effects of electroacupuncture by acupoint selection on the expression level of cortical neuronal anti-apoptotic Bcl-2 protein and the apoptotic executive protein, caspase-3, in rat models of focal cerebral ischemia/reperfusion.DESIGN, TIME AND SETTING: This randomized grouping, neural cell and molecular biology animal experiment was performed at the Laboratory of Pharmacology of Traditional Chinese Medicine and the Laboratory Animal Center of Henan Institute of Traditional Chinese Medicine between November 2006 and May 2007.MATERIALS: Atotal of 40 healthy male adult Sprague-Dawley rats were randomly and evenly divided into four groups: sham-operated, model, electroacupuncture and non-acupoint control. G6895 electro-acupuncture instruments were purchased from Shanghai Huayi Instrument Factory, China. Caspase-3, Bcl-2 and Bax kits were provided by Wuhan Boster Bioengineering Co., Ltd., China.METHODS: Middle cerebral artery occlusion was induced in the model, electroacupuncture and non-acupoint groups. In the electroacupuncture group, the acupoints Jianyu (LI15), Waiguan (SJ5), Biguan (ST31), and Zusanli (ST36) were given electroacupuncture. In the non-acupoint control group, at each time point (immediately after ischemia and after reperfusion, or 2 hours after reperfusion), electroacupuncture was performed at the midpoints of Tianquan (PC2)-Quze (PC 3) line, Quze (PC 3)-Ximen (PC4) line, Zuwuli (LRlO)-Yinbao (LRg) line, and Xiguan (LR7)-Zhongdu (LR6) line. Electroacupuncture parameters were set with a continuous wave with a frequency of 10 Hz, wave width 0.6 ms, voltage 1.5-3.0 V, and a duration of 10 minutes. The sham-operated and model groups received only animal fixation without electroacupuncture procedure.MAIN OUTCOME MEASURES: Five rats were selected from

  1. Continuous measurement of cerebral cortical blood flow by laser-Doppler flowmetry in a rat stroke model

    Energy Technology Data Exchange (ETDEWEB)

    Dirnagl, U.; Kaplan, B.; Jacewicz, M.; Pulsinelli, W. (Cornell Univ. Medical College, New York, NY (USA))

    1989-10-01

    Laser-Doppler flowmetry (LDF), a new method allowing instantaneous, continuous, and noninvasive measurements of microcirculatory blood flow in a small tissue sample, was evaluated for its accuracy in monitoring regional cerebral blood flow (rCBF) in the cortical microcirculation after focal cerebral ischemia. Wistar and spontaneously hypertensive rats (SHR, n = 19) were subjected to permanent occlusion of the middle cerebral and common carotid arteries. Absolute rCBF in a tissue sample of the ischemic hemisphere was measured autoradiographically with ({sup 14}C)iodoantipyrine as a tracer and compared to rCBF measured by LDF. Additionally, the percent change in rCBF between baseline and ischemic values was compared for both methods. Absolute rCBF values recorded with LDF correlated poorly (r = 0.54) with ({sup 14}C)iodoantipyrine measurements. In contrast LDF readings expressed as a percentage of ischemic vs. preocclusion readings (relative LDF readings) correlated very well (r = 0.91) with the percent change in (14C)iodoantipyrine measurements. We conclude that LDF does not provide accurate measurements of absolute rCBF values but this method allows accurate measurements of changes in rCBF due to induction of focal cerebral ischemia.

  2. Continuous measurement of cerebral cortical blood flow by laser-Doppler flowmetry in a rat stroke model.

    Science.gov (United States)

    Dirnagl, U; Kaplan, B; Jacewicz, M; Pulsinelli, W

    1989-10-01

    Laser-Doppler flowmetry (LDF), a new method allowing instantaneous, continuous, and noninvasive measurements of microcirculatory blood flow in a small tissue sample, was evaluated for its accuracy in monitoring regional cerebral blood flow (rCBF) in the cortical microcirculation after focal cerebral ischemia. Wistar and spontaneously hypertensive rats (SHR, n = 19) were subjected to permanent occlusion of the middle cerebral and common carotid arteries. Absolute rCBF in a tissue sample of the ischemic hemisphere was measured autoradiographically with [14C]iodoantipyrine as a tracer and compared to rCBF measured by LDF. Additionally, the percent change in rCBF between baseline and ischemic values was compared for both methods. Absolute rCBF values recorded with LDF correlated poorly (r = 0.54) with [14C]iodoantipyrine measurements. In contrast LDF readings expressed as a percentage of ischemic vs. preocclusion readings (relative LDF readings) correlated very well (r = 0.91) with the percent change in [14C]iodoantipyrine measurements. We conclude that LDF does not provide accurate measurements of absolute rCBF values but this method allows accurate measurements of changes in rCBF due to induction of focal cerebral ischemia.

  3. Trends and Properties of Human Cerebral Cortex: Correlations with Cortical Myelin Content

    OpenAIRE

    Glasser, Matthew F.; Goyal, Manu S.; Preuss, Todd M; Raichle, Marcus E.; Van Essen, David C.

    2013-01-01

    “In vivo Brodmann mapping” or non-invasive cortical parcellation using MRI, especially by measuring cortical myelination, has recently become a popular research topic, though myeloarchitectonic cortical parcellation in humans previously languished in favor of cytoarchitecture. We review recent in vivo myelin mapping studies and discuss some of the different methods for estimating myelin content. We discuss some ways in which myelin maps may improve surface registration and be useful for cross...

  4. Cortical morphometry and IQ in VLBW children without cerebral palsy born in 2003–2007

    Directory of Open Access Journals (Sweden)

    Anne Elisabeth Sølsnes

    2015-01-01

    We conclude that cortical deviations are evident in childhood even in VLBW children born in 2003–2007 who have received state of the art medical treatment in the perinatal period and who did not present with focal brain injuries on neonatal ultrasonography. The cortical deviations were associated with reduced cognitive functioning.

  5. Cerebral cortical tissue damage after hemorrhagic hypotension in near-term born lambs.

    NARCIS (Netherlands)

    Os, S.H.G. van; Tweel, E. van den; Egberts, H.; Hopman, J.; Ruitenbeek, W.; Bel, F. van; Groenendaal, F.; Bor, M. van de

    2006-01-01

    Hypotension reduces cerebral O(2) supply, which may result in brain cell damage and loss of brain cell function in the near-term neonate. The aim is to elucidate 1) to what extent the functional disturbance of the cerebral cortex, as measured with electrocortical brain activity (ECBA), is related to

  6. Inhibitory stabilization and visual coding in cortical circuits with multiple interneuron subtypes.

    Science.gov (United States)

    Litwin-Kumar, Ashok; Rosenbaum, Robert; Doiron, Brent

    2016-03-01

    Recent anatomical and functional characterization of cortical inhibitory interneurons has highlighted the diverse computations supported by different subtypes of interneurons. However, most theoretical models of cortex do not feature multiple classes of interneurons and rather assume a single homogeneous population. We study the dynamics of recurrent excitatory-inhibitory model cortical networks with parvalbumin (PV)-, somatostatin (SOM)-, and vasointestinal peptide-expressing (VIP) interneurons, with connectivity properties motivated by experimental recordings from mouse primary visual cortex. Our theory describes conditions under which the activity of such networks is stable and how perturbations of distinct neuronal subtypes recruit changes in activity through recurrent synaptic projections. We apply these conclusions to study the roles of each interneuron subtype in disinhibition, surround suppression, and subtractive or divisive modulation of orientation tuning curves. Our calculations and simulations determine the architectural and stimulus tuning conditions under which cortical activity consistent with experiment is possible. They also lead to novel predictions concerning connectivity and network dynamics that can be tested via optogenetic manipulations. Our work demonstrates that recurrent inhibitory dynamics must be taken into account to fully understand many properties of cortical dynamics observed in experiments.

  7. The circadian oscillator of the cerebral cortex: molecular, biochemical and behavioral effects of deleting the Arntl clock gene in cortical neurons

    DEFF Research Database (Denmark)

    Bering, Tenna; Carstensen, Mikkel Bloss; Wörtwein, Gitta

    2017-01-01

    prolonged immobility periods in the knockout mouse indicative of a depressive-like behavioral state. This phenotype was accompanied by reduced norepinephrine levels in the cerebral cortex. Our data show that Arntl is required for normal cortical clock function and further give reason to suspect...... that the circadian oscillator of the cerebral cortex is involved in regulating both circadian biology and mood-related behavior and biochemistry....

  8. An evo-devo approach to thyroid hormones in cerebral and cerebellar cortical development: etiological implications for autism.

    Science.gov (United States)

    Berbel, Pere; Navarro, Daniela; Román, Gustavo C

    2014-01-01

    The morphological alterations of cortical lamination observed in mouse models of developmental hypothyroidism prompted the recognition that these experimental changes resembled the brain lesions of children with autism; this led to recent studies showing that maternal thyroid hormone deficiency increases fourfold the risk of autism spectrum disorders (ASD), offering for the first time the possibility of prevention of some forms of ASD. For ethical reasons, the role of thyroid hormones on brain development is currently studied using animal models, usually mice and rats. Although mammals have in common many basic developmental principles regulating brain development, as well as fundamental basic mechanisms that are controlled by similar metabolic pathway activated genes, there are also important differences. For instance, the rodent cerebral cortex is basically a primary cortex, whereas the primary sensory areas in humans account for a very small surface in the cerebral cortex when compared to the associative and frontal areas that are more extensive. Associative and frontal areas in humans are involved in many neurological disorders, including ASD, attention deficit-hyperactive disorder, and dyslexia, among others. Therefore, an evo-devo approach to neocortical evolution among species is fundamental to understand not only the role of thyroid hormones and environmental thyroid disruptors on evolution, development, and organization of the cerebral cortex in mammals but also their role in neurological diseases associated to thyroid dysfunction.

  9. An evo-devo approach to thyroid hormones in cerebral and cerebellar cortical development: Etiological implications for autism

    Directory of Open Access Journals (Sweden)

    Pere eBerbel

    2014-09-01

    Full Text Available The morphological alterations of cortical lamination observed in mouse models of developmental hypothyroidism prompted the recognition that these experimental changes resembled the brain lesions of children with autism; this led to recent studies showing that maternal thyroid hormone deficiency increases fourfold the risk of ASD, offering for the first time the possibility of prevention of some forms of autism spectrum disorders (ASD. For ethical reasons, the role of thyroid hormones on brain development is currently studied using animal models, usually mice and rats. Although mammals have in common many basic developmental principles regulating brain development, as well as fundamental basic mechanisms that are controlled by similar metabolic pathway activated genes, there are also important differences. For instance, the rodent cerebral cortex is basically a primary cortex, whereas the primary sensory areas in humans account for a very small surface in the cerebral cortex when compared to the associative and frontal areas that are more extensive. Associative and frontal areas in humans are involved in many neurological disorders, including ASD, attention deficit-hyperactive disorder (ADHD and dyslexia, among others. Therefore, an evo-devo approach to neocortical evolution among species is fundamental to understand not only the role of thyroid hormones and environmental thyroid disruptors on evolution, development and organization of the cerebral cortex in mammals, but also their role in neurological diseases associated to thyroid dysfunction.

  10. Neuregulin 3 Mediates Cortical Plate Invasion and Laminar Allocation of GABAergic Interneurons

    Directory of Open Access Journals (Sweden)

    Giorgia Bartolini

    2017-01-01

    Full Text Available Neural circuits in the cerebral cortex consist of excitatory pyramidal cells and inhibitory interneurons. These two main classes of cortical neurons follow largely different genetic programs, yet they assemble into highly specialized circuits during development following a very precise choreography. Previous studies have shown that signals produced by pyramidal cells influence the migration of cortical interneurons, but the molecular nature of these factors has remained elusive. Here, we identified Neuregulin 3 (Nrg3 as a chemoattractive factor expressed by developing pyramidal cells that guides the allocation of cortical interneurons in the developing cortical plate. Gain- and loss-of-function approaches reveal that Nrg3 modulates the migration of interneurons into the cortical plate in a process that is dependent on the tyrosine kinase receptor ErbB4. Perturbation of Nrg3 signaling in conditional mutants leads to abnormal lamination of cortical interneurons. Nrg3 is therefore a critical mediator in the assembly of cortical inhibitory circuits.

  11. Functional MRI of the immediate impact of transcranial magnetic stimulation on cortical and subcortical motor circuits.

    Science.gov (United States)

    Bestmann, Sven; Baudewig, Jürgen; Siebner, Hartwig R; Rothwell, John C; Frahm, Jens

    2004-04-01

    Recent studies indicate that the cortical effects of transcranial magnetic stimulation (TMS) may not be localized to the site of stimulation, but spread to other distant areas. Using echo-planar imaging with blood-oxygenation-level-dependent (BOLD) contrast at 3 Tesla, we measured MRI signal changes in cortical and subcortical motor regions during high-frequency (3.125 Hz) repetitive TMS (rTMS) of the left sensorimotor cortex (M1/S1) at intensities above and below the active motor threshold in healthy humans. The supra- and subthreshold nature of the TMS pulses was confirmed by simultaneous electromyographic monitoring of a hand muscle. Suprathreshold rTMS activated a network of primary and secondary cortical motor regions including M1/S1, supplementary motor area, dorsal premotor cortex, cingulate motor area, the putamen and thalamus. Subthreshold rTMS elicited no MRI-detectable activity in the stimulated M1/S1, but otherwise led to a similar activation pattern as obtained for suprathreshold stimulation though at reduced intensity. In addition, we observed activations within the auditory system, including the transverse and superior temporal gyrus, inferior colliculus and medial geniculate nucleus. The present findings support the notion that re-afferent feedback from evoked movements represents the dominant input to the motor system via M1 during suprathreshold stimulation. The BOLD MRI changes in motor areas distant from the site of subthreshold stimulation are likely to originate from altered synaptic transmissions due to induced excitability changes in M1/S1. They reflect the capability of rTMS to target both local and remote brain regions as tightly connected constituents of a cortical and subcortical network.

  12. Cognitive enhancers versus addictive psychostimulants: The good and bad side of dopamine on prefrontal cortical circuits.

    Science.gov (United States)

    Bisagno, Veronica; González, Betina; Urbano, Francisco J

    2016-07-01

    In this review we describe how highly addictive psychostimulants such as cocaine and methamphetamine actions might underlie hypoexcitabilty in frontal cortical areas observed in clinical and preclinical models of psychostimulant abuse. We discuss new mechanisms that describe how increments on synaptic dopamine release are linked to reduce calcium influx in both pre and postsynaptic compartments on medial PFC networks, therefore modulating synaptic integration and information. Sustained DA neuromodulation by addictive psychostimulants can "lock" frontal cortical networks in deficient states. On the other hand, other psychostimulants such as modafinil and methylphenidate are considered pharmacological neuroenhancement agents that are popular among healthy people seeking neuroenhancement. More clinical and preclinical research is needed to further clarify mechanisms of actions and physiological effects of cognitive enhancers which show an opposite pattern compared to chronic effect of addictive psychostimulants: they appear to increase cortical excitability. In conclusion, studies summarized here suggest that there is frontal cortex hypoactivity and deficient inhibitory control in drug-addicted individuals. Thus, additional research on physiological effects of cognitive enhancers like modafinil and methylphenidate seems necessary in order to expand current knowledge on mechanisms behind their therapeutic role in the treatment of addiction and other neuropsychiatric disorders.

  13. Endogenous cortical rhythms determine cerebral specialization for speech perception and production

    DEFF Research Database (Denmark)

    Giraud, Anne-Lise; Kleinschmidt, Andreas; Poeppel, David

    2007-01-01

    Across multiple timescales, acoustic regularities of speech match rhythmic properties of both the auditory and motor systems. Syllabic rate corresponds to natural jaw-associated oscillatory rhythms, and phonemic length could reflect endogenous oscillatory auditory cortical properties. Hemispheric...... that spontaneous EEG power variations within the gamma range (phonemic rate) correlate best with left auditory cortical synaptic activity, while fluctuations within the theta range correlate best with that in the right. Power fluctuations in both ranges correlate with activity in the mouth premotor region...

  14. EFFECTS OF CEREBRAL CORTICAL CONCIS ON CELL PROLIFERATION OF THE SUBVENTRICULAR ZONE IN ADULT RATS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Mechanical injuries to the external regions ofthe brain including the cerebral cortex and otherparts of the telencephalon are common yet relativelyuntreatable[1].The predicament in recovery frombrain injury is that the adult central nervous systemis generally thought to be incapable of replacingdead neurons.As the SVZis nowknownto be neu-rogenic andis in close proxi mitytothe cerebral cor-tex and other functionally i mportant forebrain nu-clei,hope has risen that its neurogenesis may be co-opted for repair[...

  15. Functions of gamma-band synchronization in cognition: from single circuits to functional diversity across cortical and subcortical systems.

    Science.gov (United States)

    Bosman, Conrado A; Lansink, Carien S; Pennartz, Cyriel M A

    2014-06-01

    Gamma-band activity (30-90 Hz) and the synchronization of neural activity in the gamma-frequency range have been observed in different cortical and subcortical structures and have been associated with different cognitive functions. However, it is still unknown whether gamma-band synchronization subserves a single universal function or a diversity of functions across the full spectrum of cognitive processes. Here, we address this question reviewing the mechanisms of gamma-band oscillation generation and the functions associated with gamma-band activity across several cortical and subcortical structures. Additionally, we raise a plausible explanation of why gamma rhythms are found so ubiquitously across brain structures. Gamma band activity originates from the interplay between inhibition and excitation. We stress that gamma oscillations, associated with this interplay, originate from basic functional motifs that conferred advantages for low-level system processing and multiple cognitive functions throughout evolution. We illustrate the multifunctionality of gamma-band activity by considering its role in neural systems for perception, selective attention, memory, motivation and behavioral control. We conclude that gamma-band oscillations support multiple cognitive processes, rather than a single one, which, however, can be traced back to a limited set of circuit motifs which are found universally across species and brain structures.

  16. 20-Hydroxyeicosatetraenoic Acid Inhibition by HET0016 Offers Neuroprotection, Decreases Edema, and Increases Cortical Cerebral Blood Flow in a Pediatric Asphyxial Cardiac Arrest Model in Rats.

    Science.gov (United States)

    Shaik, Jafar Sadik B; Poloyac, Samuel M; Kochanek, Patrick M; Alexander, Henry; Tudorascu, Dana L; Clark, Robert Sb; Manole, Mioara D

    2015-11-01

    Vasoconstrictive and vasodilatory eicosanoids generated after cardiac arrest (CA) may contribute to cerebral vasomotor disturbances and neurodegeneration. We evaluated the balance of vasodilator/vasoconstrictor eicosanoids produced by cytochrome P450 (CYP) metabolism, and determined their role on cortical perfusion, functional outcome, and neurodegeneration after pediatric asphyxial CA. Cardiac arrest of 9 and 12 minutes was induced in 16- to 18-day-old rats. At 5 and 120 minutes after CA, we quantified the concentration of CYP eicosanoids in the cortex and subcortical areas. In separate rats, we inhibited 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis after CA and assessed cortical cerebral blood flow (CBF), neurologic deficit score, neurodegeneration, and edema. After 9 minutes of CA, vasodilator eicosanoids markedly increased versus sham. Conversely, after 12 minutes of CA, vasoconstrictor eicosanoid 20-HETE increased versus sham, without compensatory increases in vasodilator eicosanoids. Inhibition of 20-HETE synthesis after 12 minutes of CA decreased cortical 20-HETE levels, increased CBF, reduced neurologic deficits at 3 hours, and reduced neurodegeneration and edema at 48 hours versus vehicle-treated rats. In conclusion, cerebral vasoconstrictor eicosanoids increased after a pediatric CA of 12 minutes. Inhibition of 20-HETE synthesis improved cortical perfusion and short-term neurologic outcome. These results suggest that alterations in CYP eicosanoids have a role in cerebral hypoperfusion and neurodegeneration after CA and may represent important therapeutic targets.

  17. Two functional inhibitory circuits are comprised of a heterogeneous population of fast-spiking cortical interneurons.

    Science.gov (United States)

    Li, P; Huntsman, M M

    2014-04-18

    Cortical fast spiking (FS) interneurons possess autaptic, synaptic, and electrical synapses that serve to mediate a fast, coordinated response to their postsynaptic targets. While FS interneurons are known to participate in numerous and diverse actions, functional subgroupings within this multi-functional interneuron class remain to be identified. In the present study, we examined parvalbumin-positive FS interneurons in layer 4 of the primary somatosensory (barrel) cortex - a brain region well-known for specialized inhibitory function. Here we show that FS interneurons fall into two broad categories identified by the onset of the first action potential in a depolarizing train as: "delayed firing FS interneurons (FSD) and early onset firing FS interneurons (FSE). Subtle variations in action potential firing reveal six subtypes within these two categories: delayed non-accommodating (FSD-NAC), delayed stuttering (FSD-STUT), early onset stuttering (FSE-STUT), early onset-late spiking (FSE-LS), early onset early-spiking (FSE-ES), and early onset accommodating (FSE-AC). Using biophysical criteria previously employed to distinguish neuronal cell types, the FSD and FSE categories exhibit several shared biophysical and synaptic properties that coincide with the notion of specificity of inhibitory function within the cortical FS interneuron class.

  18. Alterations in Cerebral Cortical Glucose and Glutamine Metabolism Precedes Amyloid Plaques in the APPswe/PSEN1dE9 Mouse Model of Alzheimer's Disease

    DEFF Research Database (Denmark)

    Andersen, Jens V; Christensen, Sofie K; Aldana, Blanca I

    2017-01-01

    Alterations in brain energy metabolism have been suggested to be of fundamental importance for the development of Alzheimer's disease (AD). However, specific changes in brain energetics in the early stages of AD are poorly known. The aim of this study was to investigate cerebral energy metabolism...... in the APPswe/PSEN1dE9 mouse prior to amyloid plaque formation. Acutely isolated cerebral cortical and hippocampal slices of 3-month-old APPswe/PSEN1dE9 and wild-type control mice were incubated in media containing [U-(13)C]glucose, [1,2-(13)C]acetate or [U-(13)C]glutamine, and tissue extracts were analyzed...... by mass spectrometry. The ATP synthesis rate of isolated whole-brain mitochondria was assessed by an on-line luciferin-luciferase assay. Significantly increased (13)C labeling of intracellular lactate and alanine and decreased tricarboxylic acid (TCA) cycle activity were observed from cerebral cortical...

  19. Cortical and Subcortical Structural Plasticity Associated with the Glioma Volumes in Patients with Cerebral Gliomas Revealed by Surface-Based Morphometry

    Directory of Open Access Journals (Sweden)

    Jinping Xu

    2017-06-01

    Full Text Available Postlesional plasticity has been identified in patients with cerebral gliomas by inducing a large functional reshaping of brain networks. Although numerous non-invasive functional neuroimaging methods have extensively investigated the mechanisms of this functional redistribution in patients with cerebral gliomas, little effort has been made to investigate the structural plasticity of cortical and subcortical structures associated with the glioma volume. In this study, we aimed to investigate whether the contralateral cortical and subcortical structures are able to actively reorganize by themselves in these patients. The compensation mechanism following contralateral cortical and subcortical structural plasticity is considered. We adopted the surface-based morphometry to investigate the difference of cortical and subcortical gray matter (GM volumes in a cohort of 14 healthy controls and 13 patients with left-hemisphere cerebral gliomas [including 1 patients with World Health Organization (WHO I, 8 WHO II, and 4 WHO III]. The glioma volume ranges from 5.1633 to 208.165 cm2. Compared to healthy controls, we found significantly increased GM volume of the right cuneus and the left thalamus, as well as a trend toward enlargement in the right globus pallidus in patients with cerebral gliomas. Moreover, the GM volumes of these regions were positively correlated with the glioma volumes of the patients. These results provide evidence of cortical and subcortical enlargement, suggesting the usefulness of surface-based morphometry to investigate the structural plasticity. Moreover, the structural plasticity might be acted as the compensation mechanism to better fulfill its functions in patients with cerebral gliomas as the gliomas get larger.

  20. Regulation of Cerebral Cortical Size and Neuron Number by Fibroblast Growth Factors: Implications for Autism

    Science.gov (United States)

    Vaccarino, Flora M.; Grigorenko, Elena L.; Smith, Karen Muller; Stevens, Hanna E.

    2009-01-01

    Increased brain size is common in children with autism spectrum disorders. Here we propose that an increased number of cortical excitatory neurons may underlie the increased brain volume, minicolumn pathology and excessive network excitability, leading to sensory hyper-reactivity and seizures, which are often found in autism. We suggest that…

  1. Electro-cortical signs of early neuronal damage following transient global cerebral ischemia in rat

    DEFF Research Database (Denmark)

    Moldovan, M; Zagrean, Ana-Maria; Avramescu, S;

    2004-01-01

    During recovery after a transient global cerebral ischemia (TGCI), rat electrocorticogram (ECoG) shows epochs of synchronized activity (SA) alternating with epochs of low amplitude background activity (BA). The aim of this study was to compare the changes in these electrical activities during a 3...

  2. Point application with Angong Niuhuang sticker protects hippocampal and cortical neurons in rats with cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Dong-shu Zhang

    2015-01-01

    Full Text Available Angong Niuhuang pill, a Chinese materia medica preparation, can improve neurological functions after acute ischemic stroke. Because of its inconvenient application and toxic components (Cinnabaris and Realgar, we used transdermal enhancers to deliver Angong Niuhuang pill by modern technology, which expanded the safe dose range and clinical indications. In this study, Angong Niuhuang stickers administered at different point application doses (1.35, 2.7, and 5.4 g/kg were administered to the Dazhui (DU14, Qihai (RN6 and Mingmen (DU4 of rats with chronic cerebral ischemia, for 4 weeks. The Morris water maze was used to determine the learning and memory ability of rats. Hematoxylin-eosin staining and Nissl staining were used to observe neuronal damage of the cortex and hippocampal CA1 region in rats with chronic cerebral ischemia. The middle- and high-dose point application of Angong Niuhuang stickers attenuated neuronal damage in the cortex and hippocampal CA1 region, and improved the memory of rats with chronic cerebral ischemia with an efficacy similar to interventions by electroacupuncture at Dazhui (DU14, Qihai (RN6 and Mingmen (DU4. Our experimental findings indicate that point application with Angong Niuhuang stickers can improve cognitive function after chronic cerebral ischemia in rats and is neuroprotective with an equivalent efficacy to acupuncture.

  3. Pathological features of cerebral cortical capillaries are doubled in Alzheimer's disease and Parkinson's disease

    NARCIS (Netherlands)

    Farkas, E; De Jong, GI; de Vos, RAI; Steur, ENHJ; Luiten, PGM

    2000-01-01

    Cerebral capillaries represent a major interface between the general circulation and the central nervous system and are responsible for sufficient and selective nutrient transport to the brain. Structural damage or dysfunctioning carrier systems of such an active barrier leads to compromised

  4. Left-right cortical asymmetries of regional cerebral blood flow during listening to words

    DEFF Research Database (Denmark)

    Nishizawa, Y; Olsen, T S; Larsen, B

    1982-01-01

    1. Regional cerebral blood flow (rCBF) was measured during rest and during listening to simple words. The xenon-133 intracarotid technique was used and results were obtained from 254 regions of seven right hemispheres and seven left hemispheres. The measurements were performed just after carotid ...

  5. Mapping cortical thickness of the patients with unilateral end-stage open angle glaucoma on planar cerebral cortex maps.

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    Piotr Bogorodzki

    Full Text Available PURPOSE: To estimate and compare cerebral cortex thickness in patients with unilateral end-stage glaucoma with that of age-matched individuals with unaffected vision. METHODS: 14 patients with unilateral end-stage primary open angle glaucoma (POAG and 12 age-matched control individuals with no problems with vision were selected for the study based on detailed ophthalmic examination. For each participant 3D high-resolution structural brain T1-weighted magnetization prepared MR images were acquired on a 3.0 T scanner. Brain cortex thickness was estimated using the FreeSurfer image analysis environment. After warping of subjects' cortical surfaces to FreeSurfer common space, differences between POAG and control groups were inferred at the group analysis level with the General Linear Model. RESULTS: The analysis performed revealed local thinning in the visual cortex areas in the POAG group. Statistically significant differences form 600 mm2 clusters located in the Brodmann area BA19 in the left and right hemisphere. CONCLUSION: Unilateral vision loss due to end-stage neuropathy from POAG is associated with significant thinning of cortical areas employed in vision.

  6. NEURAL CORRELATES FOR APATHY: FRONTAL - PREFRONTAL AND PARIETAL CORTICAL - SUBCORTICAL CIRCUITS

    Directory of Open Access Journals (Sweden)

    Rita Moretti

    2016-12-01

    Full Text Available Apathy is an uncertain nosographical entity, which includes reduced motivation, abulia, decreased empathy, and lack of emotional invovlement; it is an important and heavy-burden clinical condition which strongly impacts in every day life events, affects the common daily living abilities, reduced the inner goal directed behavior, and gives the heaviest burden on caregivers. Is a quite common comorbidity of many neurological disease, However, there is no definite consensus on the role of apathy in clinical practice, no definite data on anatomical circuits involved in its development, and no definite instrument to detect it at bedside. As a general observation, the occurrence of apathy is connected to damage of prefrontal cortex (PFC and basal ganglia; emotional affective apathy may be related to the orbitomedial PFC and ventral striatum; cognitive apathy may be associated with dysfunction of lateral PFC and dorsal caudate nuclei; deficit of autoactivation may be due to bilateral lesions of the internal portion of globus pallidus, bilateral paramedian thalamic lesions, or the dorsomedial portion of PFC. On the other hand, apathy severity has been connected to neurofibrillary tangles density in the anterior cingulate gyrus and to grey matter atrophy in the anterior cingulate (ACC and in the left medial frontal cortex, confirmed by functional imaging studies. These neural networks are linked to projects, judjing and planning, execution and selection common actions, and through the basolateral amygdala and nucleus accumbens projects to the frontostriatal and to the dorsolateral prefrontal cortex. Therefore, an alteration of these circuitry caused a lack of insight, a reduction of decision-making strategies and a reduced speedness in action decsion, major resposnible for apathy. Emergent role concerns also the parietal cortex, with its direct action motivation control.We will discuss the importance of these circuits in different pathologies

  7. Mild cognitive impairment, poor episodic memory, and late-life depression are associated with cerebral cortical thinning and increased white matter hyperintensities

    Directory of Open Access Journals (Sweden)

    Motonobu eFujishima

    2014-11-01

    Full Text Available In various independent studies to date, cerebral cortical thickness and white matter hyperintensity (WMH volume have been associated with episodic memory, depression, and mild cognitive impairment (MCI. The aim of this study was to uncover variations in cortical thickness and WMH volume in association with episodic memory, depressive state, and the presence of MCI simultaneously in a single study population. The participants were 186 individuals with MCI (clinical dementia rating [CDR] of 0.5 and 136 healthy elderly controls (HCs; CDR of 0 drawn from two community-based cohort studies in northern Japan. We computed cerebral cortical thickness and WMH volume by using MR scans and statistically analyzed differences in these indices between HCs and MCI participants. We also assessed the associations of these indices with memory performance and depressive state in participants with MCI. Compared with HCs, MCI participants exhibited thinner cortices in the temporal and inferior parietal lobes and greater WMH volumes in the corona radiata and semioval center. In MCI participants, poor episodic memory was associated with thinner cortices in the left entorhinal region and increased WMH volume in the posterior periventricular regions. Compared with non-depressed MCI participants, depressed MCI participants showed reduced cortical thickness in the anterior medial temporal lobe and ambient gyrus adjacent to the amygdala bilaterally, as well as greater WMH volume as a percentage of the total intracranial volume (WMHr. A higher WMHr was associated with cortical thinning in the frontal, temporal, and parietal regions in MCI participants. These results demonstrate that episodic memory and depression are associated with both cortical thickness and WMH volume in MCI participants. Additional longitudinal studies are needed to clarify the dynamic associations and interactions among these indices.

  8. A Cortical Circuit for Sexually Dimorphic Oxytocin-Dependent Anxiety Behaviors

    Science.gov (United States)

    Li, Kun; Nakajima, Miho; Ibañez-Tallon, Ines; Heintz, Nathaniel

    2016-01-01

    SUMMARY The frequency of human social and emotional disorders varies significantly between males and females. We have recently reported that oxytocin receptor interneurons (OxtrINs) modulate female sociosexual behavior. Here we show that in male mice OxtrINs regulate anxiety-related behaviors. We demonstrate that corticotropin releasing hormone binding protein (CRHBP), an antagonist of the stress hormone CRH, is specifically expressed in OxtrINs. Production of CRHBP blocks the CRH-induced potentiation of postsynaptic layer 2/3 pyramidal cell activity of male but not female mice, thus producing an anxiolytic effect. Our data identify OxtrINs as critical for modulation of social and emotional behaviors in both females and males, and reveal a molecular mechanism that acts on local mPFC circuits to coordinate responses to OXT and CRH. They suggest that additional studies of the impact of the OXT/OXTR and CRHBP/CRH pathways in males and females will be important in development of gender specific therapies. PMID:27641503

  9. Individual language experience modulates rapid formation of cortical memory circuits for novel words

    Science.gov (United States)

    Kimppa, Lilli; Kujala, Teija; Shtyrov, Yury

    2016-01-01

    Mastering multiple languages is an increasingly important ability in the modern world; furthermore, multilingualism may affect human learning abilities. Here, we test how the brain’s capacity to rapidly form new representations for spoken words is affected by prior individual experience in non-native language acquisition. Formation of new word memory traces is reflected in a neurophysiological response increase during a short exposure to novel lexicon. Therefore, we recorded changes in electrophysiological responses to phonologically native and non-native novel word-forms during a perceptual learning session, in which novel stimuli were repetitively presented to healthy adults in either ignore or attend conditions. We found that larger number of previously acquired languages and earlier average age of acquisition (AoA) predicted greater response increase to novel non-native word-forms. This suggests that early and extensive language experience is associated with greater neural flexibility for acquiring novel words with unfamiliar phonology. Conversely, later AoA was associated with a stronger response increase for phonologically native novel word-forms, indicating better tuning of neural linguistic circuits to native phonology. The results suggest that individual language experience has a strong effect on the neural mechanisms of word learning, and that it interacts with the phonological familiarity of the novel lexicon. PMID:27444206

  10. [Cortical blindness].

    Science.gov (United States)

    Chokron, S

    2014-02-01

    Cortical blindness refers to a visual loss induced by a bilateral occipital lesion. The very strong cooperation between psychophysics, cognitive psychology, neurophysiology and neuropsychology these latter twenty years as well as recent progress in cerebral imagery have led to a better understanding of neurovisual deficits, such as cortical blindness. It thus becomes possible now to propose an earlier diagnosis of cortical blindness as well as new perspectives for rehabilitation in children as well as in adults. On the other hand, studying complex neurovisual deficits, such as cortical blindness is a way to infer normal functioning of the visual system.

  11. An implantable wireless neural interface for recording cortical circuit dynamics in moving primates

    Science.gov (United States)

    Borton, David A.; Yin, Ming; Aceros, Juan; Nurmikko, Arto

    2013-04-01

    Objective. Neural interface technology suitable for clinical translation has the potential to significantly impact the lives of amputees, spinal cord injury victims and those living with severe neuromotor disease. Such systems must be chronically safe, durable and effective. Approach. We have designed and implemented a neural interface microsystem, housed in a compact, subcutaneous and hermetically sealed titanium enclosure. The implanted device interfaces the brain with a 510k-approved, 100-element silicon-based microelectrode array via a custom hermetic feedthrough design. Full spectrum neural signals were amplified (0.1 Hz to 7.8 kHz, 200× gain) and multiplexed by a custom application specific integrated circuit, digitized and then packaged for transmission. The neural data (24 Mbps) were transmitted by a wireless data link carried on a frequency-shift-key-modulated signal at 3.2 and 3.8 GHz to a receiver 1 m away by design as a point-to-point communication link for human clinical use. The system was powered by an embedded medical grade rechargeable Li-ion battery for 7 h continuous operation between recharge via an inductive transcutaneous wireless power link at 2 MHz. Main results. Device verification and early validation were performed in both swine and non-human primate freely-moving animal models and showed that the wireless implant was electrically stable, effective in capturing and delivering broadband neural data, and safe for over one year of testing. In addition, we have used the multichannel data from these mobile animal models to demonstrate the ability to decode neural population dynamics associated with motor activity. Significance. We have developed an implanted wireless broadband neural recording device evaluated in non-human primate and swine. The use of this new implantable neural interface technology can provide insight into how to advance human neuroprostheses beyond the present early clinical trials. Further, such tools enable mobile

  12. Abnormal white matter tractography of visual pathways detected by high-angular-resolution diffusion imaging (HARDI) corresponds to visual dysfunction in cortical/cerebral visual impairment

    OpenAIRE

    Bauer, Corinna M.; Heidary, Gena; Koo, Bang-Bon; Killiany, Ronald J.; Bex, Peter; Merabet, Lotfi B.

    2014-01-01

    Cortical (cerebral) visual impairment (CVI) is characterized by visual dysfunction associated with damage to the optic radiations and/or visual cortex. Typically it results from pre- or perinatal hypoxic damage to postchiasmal visual structures and pathways. The neuroanatomical basis of this condition remains poorly understood, particularly with regard to how the resulting maldevelopment of visual processing pathways relates to observations in the clinical setting. We report our investigation...

  13. Effects of activated ACM on expression of signal transducers in cerebral cortical neurons of rats.

    Science.gov (United States)

    Wang, Xiaojing; Li, Zhengli; Zhu, Changgeng; Li, Zhongyu

    2007-06-01

    To explore the roles of astrocytes in the epileptogenesis, astrocytes and neurons were isolated, purified and cultured in vitro from cerebral cortex of rats. The astrocytes were activated by ciliary neurotrophic factor (CNTF) and astrocytic conditioned medium (ACM) was collected to treat neurons for 4, 8 and 12 h. By using Western blot, the expression of calmodulin dependent protein kinase II (CaMK II), inducible nitric oxide synthase (iNOS) and adenylate cyclase (AC) was detected in neurons. The results showed that the expression of CaMK II, iNOS and AC was increased significantly in the neurons treated with ACM from 4 h to 12 h (PACM and such signal pathways as NOS-NO-cGMP, Ca2+/CaM-CaMK II and AC-cAMP-PKA might take part in the signal transduction of epileptogenesis.

  14. Primary Somatosensory Cortices Contain Altered Patterns of Regional Cerebral Blood Flow in the Interictal Phase of Migraine

    Science.gov (United States)

    Hodkinson, Duncan J.; Veggeberg, Rosanna; Wilcox, Sophie L.; Scrivani, Steven; Burstein, Rami; Becerra, Lino; Borsook, David

    2015-01-01

    The regulation of cerebral blood flow (CBF) is a complex integrated process that is critical for supporting healthy brain function. Studies have demonstrated a high incidence of alterations in CBF in patients suffering from migraine with and without aura during different phases of attacks. However, the CBF data collected interictally has failed to show any distinguishing features or clues as to the underlying pathophysiology of the disease. In this study we used the magnetic resonance imaging (MRI) technique—arterial spin labeling (ASL)—to non-invasively and quantitatively measure regional CBF (rCBF) in a case-controlled study of interictal migraine. We examined both the regional and global CBF differences between the groups, and found a significant increase in rCBF in the primary somatosensory cortex (S1) of migraine patients. The CBF values in S1 were positively correlated with the headache attack frequency, but were unrelated to the duration of illness or age of the patients. Additionally, 82% of patients reported skin hypersensitivity (cutaneous allodynia) during migraine, suggesting atypical processing of somatosensory stimuli. Our results demonstrate the presence of a disease-specific functional deficit in a known region of the trigemino-cortical pathway, which may be driven by adaptive or maladaptive functional plasticity. These findings may in part explain the altered sensory experiences reported between migraine attacks. PMID:26372461

  15. Primary Somatosensory Cortices Contain Altered Patterns of Regional Cerebral Blood Flow in the Interictal Phase of Migraine.

    Directory of Open Access Journals (Sweden)

    Duncan J Hodkinson

    Full Text Available The regulation of cerebral blood flow (CBF is a complex integrated process that is critical for supporting healthy brain function. Studies have demonstrated a high incidence of alterations in CBF in patients suffering from migraine with and without aura during different phases of attacks. However, the CBF data collected interictally has failed to show any distinguishing features or clues as to the underlying pathophysiology of the disease. In this study we used the magnetic resonance imaging (MRI technique-arterial spin labeling (ASL-to non-invasively and quantitatively measure regional CBF (rCBF in a case-controlled study of interictal migraine. We examined both the regional and global CBF differences between the groups, and found a significant increase in rCBF in the primary somatosensory cortex (S1 of migraine patients. The CBF values in S1 were positively correlated with the headache attack frequency, but were unrelated to the duration of illness or age of the patients. Additionally, 82% of patients reported skin hypersensitivity (cutaneous allodynia during migraine, suggesting atypical processing of somatosensory stimuli. Our results demonstrate the presence of a disease-specific functional deficit in a known region of the trigemino-cortical pathway, which may be driven by adaptive or maladaptive functional plasticity. These findings may in part explain the altered sensory experiences reported between migraine attacks.

  16. Frontoparietal cortical atrophy with gliosis in the gray matter of cerebral cortex: case report Atrofia cortical frontoparietal com gliose na substância cinzenta do córtex cerebral: relato de caso

    Directory of Open Access Journals (Sweden)

    Paulo Roberto de Brito-Marques

    2002-06-01

    região periventricular, centro semi-oval bilateral, e alta hiperintensidade de sinal na região da cápsula interna esquerda, além de leve atrofia bilateral nos lobos frontoparietais. Tomografia cerebral por emissão de fóton único revelou hipoperfusão de intensidade moderada nos lobos frontais e severa nos parietais, especialmente à esquerda. Os achados de necrópsia evidenciaram atrofia cortical, sendo severa nos lobos frontais, moderada nos parietais e leve no terço posterior dos temporais. Havia também leve atrofia no neostriado. Do ponto de vista histopatológico, existia na camada cortical severa perda neuronal com intensa gliose gemioscítica e grau variável de status spongiosus. As colorações por hematoxilina-eosina e Bielschowsky não revelaram células baloniformes (células de Pick e corpúsculos argirofílicos (corpos de Pick, degeneração neurofibrilar ou placa senil. As reações imuno-histoquímicas foram negativas para anti-ubiquitina, anti-tau, anti-beta amilóide e proteína anti-prion.

  17. Combined heterozygosity of factor V leiden and the G20210A prothrombin gene mutation in a patient with cerebral cortical vein thrombosis.

    Science.gov (United States)

    Liu, X Y; Gabig, T G; Bang, N U

    2000-07-01

    Cerebral venous thrombosis (CVT) is a rare type of stroke with a variety of causes. Several reports have suggested that either factor V Leiden or G20210A prothrombin gene mutation is associated with an increased risk of CVT. The genetic thrombophilias are typically associated with other predisposing factors. We report a unique case of CVT in a patient with both the factor V Leiden and the G20210A prothrombin gene mutations without other identifiable precipitating factors in a 28-year-old white male in good health. MRI and cerebral arterial angiography showed cerebral cortical venous thrombosis. This case suggests that combined heterozygous individuals may be particularly prone to spontaneous thrombosis, like CVT.

  18. Cellullar insights into cerebral cortical development: focusing on the locomotion mode of neuronal migration

    Directory of Open Access Journals (Sweden)

    Takeshi eKawauchi

    2015-10-01

    Full Text Available The mammalian brain consists of numerous compartments that are closely connected with each other via neural networks, comprising the basis of higher order brain functions. The highly specialized structure originates from simple pseudostratified neuroepithelium-derived neural progenitors located near the ventricle. A long journey by neurons from the ventricular side is essential for the formation of a sophisticated brain structure, including a mammalian-specific six-layered cerebral cortex. Neuronal migration consists of several contiguous steps, but the locomotion mode comprises a large part of the migration. The locomoting neurons exhibit unique features; a radial glial fiber-dependent migration requiring the endocytic recycling of N-cadherin and a neuron-specific migration mode with dilation/swelling formation that requires the actin and microtubule organization possibly regulated by cyclin-dependent kinase 5 (Cdk5, Dcx, p27kip1, Rac1 and POSH. Here I will introduce the roles of various cellular events, such as cytoskeletal organization, cell adhesion and membrane trafficking, in the regulation of the neuronal migration, with particular focus on the locomotion mode.

  19. Effects of a group circuit progressive resistance training program compared with a treadmill training program for adolescents with cerebral palsy.

    Science.gov (United States)

    Aviram, Ronit; Harries, Netta; Namourah, Ibtisam; Amro, Akram; Bar-Haim, Simona

    2017-08-01

    To determine whether goal-directed group circuit progressive resistance exercise training (GT) can improve motor function in adolescents with cerebral palsy (CP) and to compare outcomes with a treadmill training (TT) intervention. In a multi-centered matched pairs study, 95 adolescents with spastic CP (GMFCS II-III) were allocated to GT or TT interventions for 30 bi-weekly one hour training. Outcome measures of GMFM-66, GMFM-D%, GMFM-E%, TUG, 10 meter walk test (10 MWT), and 6 minute walk test (6 MWT) were made at baseline (T1), after interventions (T2) and 6 months post training (T3). Both training programs induced significant improvement in all outcome measures (T2-T1) that were mostly retained at T3. At the end of the intervention, the GT group showed an advantage in all measured changes compared to the TT group and in percentage changes. Differences were significant (p adolescents with cerebral palsy. The GT program had generally greater benefits based on the functional measures.

  20. Cortical reorganisation of cerebral networks after childhood stroke: impact on outcome.

    Science.gov (United States)

    Kornfeld, Salome; Delgado Rodríguez, Juan Antonio; Everts, Regula; Kaelin-Lang, Alain; Wiest, Roland; Weisstanner, Christian; Mordasini, Pasquale; Steinlin, Maja; Grunt, Sebastian

    2015-06-10

    Recovery after arterial ischaemic stroke is known to largely depend on the plastic properties of the brain. The present study examines changes in the network topography of the developing brain after stroke. Effects of brain damage are best assessed by examining entire networks rather than single sites of structural lesions. Relating these changes to post-stroke neuropsychological variables and motor abilities will improve understanding of functional plasticity after stroke. Inclusion of healthy controls will provide additional insight into children's normal brain development. Resting state functional magnetic resonance imaging is a valid approach to topographically investigate the reorganisation of functional networks after a brain lesion. Transcranial magnetic stimulation provides complementary output information. This study will investigate functional reorganisation after paediatric arterial ischaemic stroke by means of resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a cross-sectional plus longitudinal study design. The general aim of this study is to better understand neuroplasticity of the developing brain after stroke in order to develop more efficacious therapy and to improve the post-stroke functional outcome. The cross-sectional part of the study will investigate the functional cerebral networks of 35 children with chronic arterial ischaemic stroke (time of the lesion >2 years). In the longitudinal part, 15 children with acute arterial ischaemic stroke (shortly after the acute phase of the stroke) will be included and investigations will be performed 3 times within the subsequent 9 months. We will also recruit 50 healthy controls, matched for age and sex. The neuroimaging and neurophysiological data will be correlated with neuropsychological and neurological variables. This study is the first to combine resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a paediatric

  1. Gender and the use of hormonal contraception in women are not associated with cerebral cortical 5-HT 2A receptor binding

    DEFF Research Database (Denmark)

    Frokjaer, V G; Erritzoe, D; Madsen, J

    2009-01-01

    Gender influences brain function including serotonergic neurotransmission, which may play a role in the well-known gender variations in vulnerability to mood and anxiety disorders. Even though hormonal replacement therapy in menopause is associated with globally increased cerebral 5-HT(2A) receptor...... binding it is not clear if gender or use of hormonal contraception exhibits associations with 5-HT(2A) receptor binding. We found no significant effect of gender on cortical 5-HT(2A) receptor binding (P=0.15, n=132). When adjusting for the personality trait neuroticism, known to be positively correlated...... to frontolimbic 5-HT(2A) receptor binding and to be more pronounced in women, again, the effect of gender was not significant (P=0.42, n=127). Also, the use of hormonal contraception (n=14) within the group of pre-menopausal women (total n=29) was not associated with cortical 5-HT(2A) receptor binding (P=0...

  2. Cerebral Angiography combined Coronary Angiography Induced Cortical Blindness%脑血管造影联合冠脉造影术后致皮质盲

    Institute of Scientific and Technical Information of China (English)

    方晓霞; 王云甫; 刘光健

    2012-01-01

    Objective To investigate the etiology,clinical manifestations and treatments of cortical blindness after cerebral angiography combined coronary angiography. Methods The clinical manifestation, treatment and prognosis of one patient with cortical blindness induced by cerebral angiography were reported,the related literatures were retrospectively analyzed. Results The clinical characteristics of cortical blindness were abrupt onset and hazardous, and its possible etiology in most studies was that the toxicity of contrast media which may destruct the blood-brain barrier transiently, then specifically entered into visual cortex and induced cortex cells injury. The principles of treatment were dilating blood vessels, alleviating cerebral edema,glucocorticoids,nerve nutrition. Conclusion Cortical blindness is a rare clinical complication of cerebral angiography, which should be diagnosed and treated as soon as possible,and take some preventive measures.%目的:探讨心脑血管造影术后皮质盲的病因、临床表现及处理方法.方法:报道1例心脑血管造影术后皮质盲的临床表现、治疗过程及治疗结果,并结合文献讨论.结果:脑血管造影术后皮质盲具有发病突然、凶险的临床特点,一般认为是术中造影剂的毒性作用,使血脑屏障一过性破坏,造影剂特异性进入视皮质,导致皮质细胞毒性损害.治疗原则为舒张血管、抗脑水肿、皮质激素、神经营养治疗.结论:心脑血管造影术后的皮质盲是一临床少见并发症,必须尽快确诊及治疗,并采取一定的预防措施防治.

  3. Nerve growth factor affects focal cerebral cortical neuronal Bcl-2 and Bax expression in a mouse model of oxyhemoglobin-induced subarachnoid hemorrhage

    Institute of Scientific and Technical Information of China (English)

    Xianfeng Jiang; Wei Shi; Jin Liang

    2008-01-01

    BACKGROUND: Studies have demonstrated that oxyhemoglobin (OxyHb) can induce brain cell apoptosis in vivo.OBJECTIVE: To observe the effects of exogenous nerve growth factor (NGF) on cerebral cortical neuronal Bcl-2 and Bax expression in mice with OxyHb-induced subarachnoid hemorrhage.DESIGN, TIME AND SETTING: A completely randomized grouping, controlled animal experiment was performed at the Experimental Center for Biomedicine, College of Medicine, Xi'an Jiaotong University between February and April 2005.MATERIALS: Fifty-four healthy, male, adult, ICR mice were included in this study. Subarachnoid hemorrhage was induced by a subarachnoid injection of OxyHb in 48 mice. Mouse NGF was obtained from Xiamcn Beidazhilu Bioengineering Co., Ltd., China.METHODS: All 54 mice were randomly divided into three groups: control (n = 6), injury (n = 24), and NGF (n = 24). The NGF group received a subarachnoidal administration of OxyHb, immediately followed by a caudal vein injection of NGF (1 μg). The injury group was injected with OxyHb, and subsequently with physiological saline. Thc control group only received intravenous physiological saline.MAIN OUTCOME MEASURES: At 1, 6, 24, and 48 hours following subarachnoid hemorrhage induction,expression levels of Bcl-2 and Bax were detected by immunohistochemistry in the cerebral cortex 3 mm anterior and posterior to the injection site.RESULTS: At all time points following OxyHb injection, cerebral cortical Bax levels were significantly higher in the injured group than in the control and NGF groups (P < 0.01). During the first 24 hours following OxyHb injection, cerebral cortical Bcl-2 levels were significantly lower in the injury group compared to the control group (P < 0.05 0.01). Between 1 and 48 hours, Bcl-2 levels were significantly higher in the NGF group than in the injury group (P < 0.01).CONCLUSION: Exogenous NGF can inhibit increased neuronal Bax expression and decreased Bcl-2expression in the cerebral cortex of mice with Oxy

  4. Circuitous embolic hemorrhagic stroke: carotid pseudoaneurysm to fetal posterior cerebral artery conduit: a case report

    Directory of Open Access Journals (Sweden)

    Hoque Romy

    2008-02-01

    Full Text Available Abstract Introduction The cervical internal carotid artery (ICA is susceptible to injury through various mechanisms, including dissection, which can lead to pseudoaneurysm formation. Pathological processes affecting the ICA, in association with an ipsilateral fetal posterior cerebral artery (PCA, resulting in parieto-occipital strokes are rarely reported. Case Presentation We present a patient with a left PCA territory, presumably embolic, stroke with early hemorrhagic transformation. The identified nidus of the embolus was a carotid artery pseudoaneurysm. Manifestations included right homonymous hemianopsia with right hemiparesis and hemisensory loss. Conclusion Our case is unique, and of clinical interest, because it illustrates both the potential anterior-posterior circulation conduit provided by a fetal origin PCA as well as the apparent early hemorrhagic transformation of embolic infarcts that can lead to further confusion from a mechanistic standpoint.

  5. Uptake of glutamate is impaired in the cortical penumbra of the rat following middle cerebral artery occlusion

    DEFF Research Database (Denmark)

    Bruhn, Torben; Christensen, Thomas; Diemer, Nils Henrik

    2003-01-01

    By using microdialysis extraction of (3)H-D-aspartate and concomitant recordings of extracellular direct current (DC) potentials, the effect of middle cerebral artery occlusion (MCAO) was studied continuously over a period of 100 min in the cerebral cortex of rats. From analysis of the DC potenti...

  6. Voxel-based statistical analysis of cerebral glucose metabolism in the rat cortical deafness model by 3D reconstruction of brain from autoradiographic images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Sung; Park, Kwang Suk [Seoul National University College of Medicine, Department of Nuclear Medicine, 28 Yungun-Dong, Chongno-Ku, Seoul (Korea); Seoul National University College of Medicine, Department of Biomedical Engineering, Seoul (Korea); Ahn, Soon-Hyun; Oh, Seung Ha; Kim, Chong Sun; Chung, June-Key; Lee, Myung Chul [Seoul National University College of Medicine, Department of Otolaryngology, Head and Neck Surgery, Seoul (Korea); Lee, Dong Soo; Jeong, Jae Min [Seoul National University College of Medicine, Department of Nuclear Medicine, 28 Yungun-Dong, Chongno-Ku, Seoul (Korea)

    2005-06-01

    Animal models of cortical deafness are essential for investigation of the cerebral glucose metabolism in congenital or prelingual deafness. Autoradiographic imaging is mainly used to assess the cerebral glucose metabolism in rodents. In this study, procedures for the 3D voxel-based statistical analysis of autoradiographic data were established to enable investigations of the within-modal and cross-modal plasticity through entire areas of the brain of sensory-deprived animals without lumping together heterogeneous subregions within each brain structure into a large region of interest. Thirteen 2-[1-{sup 14}C]-deoxy-D-glucose autoradiographic images were acquired from six deaf and seven age-matched normal rats (age 6-10 weeks). The deafness was induced by surgical ablation. For the 3D voxel-based statistical analysis, brain slices were extracted semiautomatically from the autoradiographic images, which contained the coronal sections of the brain, and were stacked into 3D volume data. Using principal axes matching and mutual information maximization algorithms, the adjacent coronal sections were co-registered using a rigid body transformation, and all sections were realigned to the first section. A study-specific template was composed and the realigned images were spatially normalized onto the template. Following count normalization, voxel-wise t tests were performed to reveal the areas with significant differences in cerebral glucose metabolism between the deaf and the control rats. Continuous and clear edges were detected in each image after registration between the coronal sections, and the internal and external landmarks extracted from the spatially normalized images were well matched, demonstrating the reliability of the spatial processing procedures. Voxel-wise t tests showed that the glucose metabolism in the bilateral auditory cortices of the deaf rats was significantly (P<0.001) lower than that in the controls. There was no significantly reduced metabolism in

  7. Temporal dynamics of cerebral blood flow, cortical damage, apoptosis, astrocyte-vasculature interaction and astrogliosis in the pericontusional region after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Sonia eVillapol

    2014-06-01

    Full Text Available Traumatic brain injury (TBI results in a loss of brain tissue at the moment of impact in the cerebral cortex. Subsequent secondary injury involves the release of molecular signals with dramatic consequences for the integrity of damaged tissue, leading to the evolution of a pericontusional-damaged area minutes to days after in the initial injury. The mechanisms behind the progression of tissue loss remain under investigation. In this study, we analyzed the spatial-temporal profile of blood flow, apoptotic and astrocytic-vascular events in the cortical regions around the impact site at time points ranging from 5 hours to 2 months after TBI. We performed a mild-moderate controlled cortical impact injury in young adult mice and analyzed the glial and vascular response to injury. We observed a dramatic decrease in perilesional cerebral blood flow (CBF immediately following the cortical impact that lasted until days later. CBF finally returned to baseline levels by 30 days post-injury (dpi. The initial impact also resulted in an immediate loss of tissue and cavity formation that gradually increased in size until 3 dpi. An increase in dying cells localized in the pericontusional region and a robust astrogliosis were also observed at 3 dpi. A strong vasculature interaction with astrocytes was established at 7 dpi. Glial scar formation began at 7 dpi and seemed to be compact by 60 dpi. Altogether, these results suggest that TBI results in a progression from acute neurodegeneration that precedes astrocytic activation, reformation of the neurovascular unit to glial scar formation. Understanding the multiple processes occurring after TBI is critical to the ability to develop neuroprotective therapeutics to ameliorate the short and long-term consequences of brain injury.

  8. A compact and realistic cerebral cortical layout derived from prewhitened resting-state fMRI time series: Cherniak's adjacency rule, size law, and metamodule grouping upheld.

    Science.gov (United States)

    Lewis, Scott M; Christova, Peka; Jerde, Trenton A; Georgopoulos, Apostolos P

    2012-01-01

    We used hierarchical tree clustering to derive a functional organizational chart of 52 human cortical areas (26 per hemisphere) from zero-lag correlations calculated between single-voxel, prewhitened, resting-state BOLD fMRI time series in 18 subjects. No special "resting-state networks" were identified. There were four major features in the resulting tree (dendrogram). First, there was a strong clustering of homotopic, left-right hemispheric areas. Second, cortical areas were concatenated in multiple, partially overlapping clusters. Third, the arrangement of the areas revealed a layout that closely resembled the actual layout of the cerebral cortex, namely an orderly progression from anterior to posterior. And fourth, the layout of the cortical areas in the tree conformed to principles of efficient, compact layout of components proposed by Cherniak. Since the tree was derived on the basis of the strength of neural correlations, these results document an orderly relation between functional interactions and layout, i.e., between structure and function.

  9. Effect of polygonatum polysaccharide on the hypoxia-induced apoptosis and necrosis in in vitro cultured cerebral cortical neurons from neonatal rats

    Institute of Scientific and Technical Information of China (English)

    Guozhu Hu; Jin Zhang; Ning Tang; Zhu Wen; Rongqing Nie

    2006-01-01

    BACKGROUND: Cardiocerebrovascular diseases induced cerebral circulation insufficiency and senile vascular dementia can result in ischemic/hypoxic apoptosis of central neurons, which we should pay more attention to and prevent and treat as early as possible. Traditional Chinese medicine possesses the unique advantage in this field. Polygonatum, a Chinese herb for invigorating qi, may play a role against the hypoxic apoptosis of brain neurons.OBJECTIVE: To observe the protective effect of polygonatum polysaccharide on hypoxia-induced apoptosis and necrosis in cerebral cortical neurons cultured in vitro.DESIGN: A comparative experiment.SETTING: Laboratory of Cell Biology, Institute of Basic Medical Sciences, Jiangxi Provincial Academy of Traditional Chinese Medicine.MATERIALS: The experiment was carried out in the Laboratory of Cell Biology, Institute of Basic Medical Sciences, Jiangxi Provincial Academy of Traditional Chinese Medicine from November 2003 to April 2005.Totally 218 Wistar rats (male or female) of clean degree within 24 hours after birth were purchased from the animal center of Jiangxi Medical College (certification number was 021-97-03).METHODS: ① Preparation of cerebral cortical neurons of rats: The cerebral cortical tissues were isolated from the Wistar rats within 24 hours after birth, and prepared to single cell suspension, and the cerebral cortical neurons of neonatal rats were in vitro cultured in serum free medium with Neurobasal plus B27Supplement. ② Observation on the non-toxic dosage of polygonatum polysaccharide on neurons: After the neurons were cultured for 4 days, polygonatum polysaccharide of different dosages (1-20 g/L) was added for continuous culture for 48 hours, the toxicity and non-toxic dosage of polygonatum polysaccharide on neurons were observed and detected with trypan blue staining. ③ Grouping: After hypoxia/reoxygenation,the cultured neurons were divided into normal control group, positive apoptotic group and polygonatum

  10. The human cerebral cortex is neither one nor many: Neuronal distribution reveals two quantitatively different zones in the grey matter, three in the white matter, and explains local variations in cortical folding

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    Pedro F. M. Ribeiro

    2013-09-01

    Full Text Available The human prefrontal cortex has been considered different in several aspects and relatively enlarged compared to the rest of the cortical areas. Here we determine whether the white and gray matter of the prefrontal portion of the human cerebral cortex have similar or different cellular compositions relative to the rest of the cortical regions by applying the Isotropic Fractionator to analyze the distribution of neurons along the entire anteroposterior axis of the cortex, and its relationship with the degree of gyrification, number of neurons under the cortical surface, and other parameters. The prefrontal region shares with the remainder of the cerebral cortex (except for occipital cortex the same relationship between cortical volume and number of neurons. In contrast, both occipital and prefrontal areas vary from other cortical areas in their connectivity through the white matter, with a systematic reduction of cortical connectivity through the white matter and an increase of the mean axon caliber along the anteroposterior axis. These two parameters explain local differences in the distribution of neurons underneath the cortical surface. We also show that local variations in cortical folding are neither a function of local numbers of neurons nor of cortical thickness, but correlate with properties of the white matter, and are best explained by the folding of the white matter surface. Our results suggest that the human cerebral cortex is divided in two zones (occipital and non-occipital that differ in how neurons distributed across their grey matter volume and in three zones (prefrontal, occipital, and non-occipital that differ in how neurons are connected through the white matter. Thus, the human prefrontal cortex has the largest fraction of neuronal connectivity through the white matter and the smallest average axonal caliber in the white matter within the cortex, although its neuronal composition fits the pattern found for other, non

  11. What is the optimal duration of middle-cerebral artery occlusion consistently resulting in isolated cortical selective neuronal loss in the spontaneously hypertensive rat?

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    Sohail eEjaz

    2015-03-01

    Full Text Available Introduction and Objectives: Selective neuronal loss (SNL in the reperfused penumbra may impact clinical recovery and is thus important to investigate. Brief proximal middle cerebral artery occlusion (MCAo results in predominantly striatal SNL, yet cortical damage is more relevant given its behavioral implications and that thrombolytic therapy mainly rescues the cortex. Distal temporary MCAo (tMCAo does target the cortex, but the optimal occlusion duration that results in isolated SNL has not been determined. In the present study we assessed different distal tMCAo durations looking for consistently pure SNL.Methods: Microclip distal tMCAo (md-tMCAo was performed in ~6-month old male spontaneously hypertensive rats (SHRs. We previously reported that 45min md-tMCAo in SHRs results in pan-necrosis in the majority of subjects. Accordingly, three shorter MCAo durations were investigated here in decremental succession, namely 30, 22 and 15mins (n=3, 3 and 7 subjects, respectively. Recanalization was confirmed by MR angiography just prior to brain collection at 28 days and T2-weighted MRI was obtained for characterization of ischemic lesions. NeuN, OX42 and GFAP immunohistochemistry appraised changes in neurons, microglia and astrocytes, respectively. Ischemic lesions were categorized into three main types: 1 pan-necrosis; 2 partial infarction; and 3 SNL. Results: Pan-necrosis or partial infarction was present in all 30min and 22min subjects, but not in the 15min group (p < 0.001, in which isolated cortical SNL was consistently present. MRI revealed characteristic hyperintense abnormalities in all rats with pan-necrosis or partial infarction, but no change in any 15min subject. Conclusions: We found that 15min distal MCAo consistently resulted in pure cortical SNL, whereas durations equal or longer than 22min consistently resulted in infarcts. This model may be of use to study the pathophysiology of cortical SNL and its prevention by appropriate

  12. Spindle Bursts in Neonatal Rat Cerebral Cortex

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    Jenq-Wei Yang

    2016-01-01

    Full Text Available Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i the functional properties of spindle bursts, (ii the mechanisms underlying their generation, (iii the synchronous patterns and cortical networks associated with spindle bursts, and (iv the physiological and pathophysiological role of spindle bursts during early cortical development.

  13. Spindle Bursts in Neonatal Rat Cerebral Cortex.

    Science.gov (United States)

    Yang, Jenq-Wei; Reyes-Puerta, Vicente; Kilb, Werner; Luhmann, Heiko J

    2016-01-01

    Spontaneous and sensory evoked spindle bursts represent a functional hallmark of the developing cerebral cortex in vitro and in vivo. They have been observed in various neocortical areas of numerous species, including newborn rodents and preterm human infants. Spindle bursts are generated in complex neocortical-subcortical circuits involving in many cases the participation of motor brain regions. Together with early gamma oscillations, spindle bursts synchronize the activity of a local neuronal network organized in a cortical column. Disturbances in spindle burst activity during corticogenesis may contribute to disorders in cortical architecture and in the activity-dependent control of programmed cell death. In this review we discuss (i) the functional properties of spindle bursts, (ii) the mechanisms underlying their generation, (iii) the synchronous patterns and cortical networks associated with spindle bursts, and (iv) the physiological and pathophysiological role of spindle bursts during early cortical development.

  14. Postpartum cortical blindness.

    Science.gov (United States)

    Faiz, Shakeel Ahmed

    2008-09-01

    A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.

  15. Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-(13)C]Glucose and [1,2-(13)C]Acetate as Substrates

    DEFF Research Database (Denmark)

    McNair, Laura F; Kornfelt, Rasmus; Walls, Anne B

    2017-01-01

    Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few...... to incubation, slices were extracted and extracts analyzed for (13)C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation...... media. Based on the measured (13)C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of (13)C-labeling observed with [U-(13)C...

  16. Detection of viable cortical neurons using benzodiazepine receptor imaging after reversible focal ischaemia in rats: comparison with regional cerebral blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshiyuki [Dept. of Radiology, Osaka National Hospital (Japan); Nakano, Takayuki; Yutani, Kenji; Nishimura, Hiroshi; Nishimura, Tsunehiko [Div. of Tracer Kinetics, Osaka University Medical School (Japan); Kusuoka, Hideo [Clinical Research Institute, Osaka National Hospital (Japan); Nakamura, Hironobu [Dept. of Radiology, Osaka University Medical School (Japan)

    2000-03-01

    To elucidate the utility of benzodiazepine receptor imaging for the detection of viable cortical neurons, dual-tracer autoradiography using iodine-125 iomazenil (IMZ) and iodine-123 N-isopropyl-4-iodoamphetamine (IMP) was performed in a model of reversible focal ischaemia during the acute and subacute phases. The right middle cerebral artery of anaesthetized rats was occluded for 60 min using an intraluminal filament and reperfused. In the acute phase study, {sup 125}I-IMZ (370 kBq) was injected via the femoral vein at 2 h after reperfusion, and {sup 123}I-IMP (37 MBq) was injected at 50 min post-injection. Rats were sacrificed 10 min after the injection of {sup 123}I-IMP. In the subacute phase study, the same procedure was performed at 5 days after reperfusion. In the acute phase, the IMP uptake was significantly decreased in almost all areas of the lesioned hemisphere, an exception being the cerebellum; however, the IMZ uptake was significantly decreased only in ischaemic cores. The discrepancy between IMZ and IMP uptake was observed in the lateral neocortex and the lateral caudate putamen (CPu), which were most frequently damaged in this ischaemic model. In the subacute phase, the IMZ uptake in lesioned rats was significantly decreased only in the parietal lobe and hippocampus, though the IMP uptake was decreased in many regions of lesioned hemispheres (the frontal, parietal cortex, CPu, hippocampus and thalamus). Histopathological findings indicated that both the IMP and the IMZ uptake was markedly decreased in necrotic areas. Although the IMP uptake was significantly decreased in the ischaemic areas, the IMZ uptake was maintained in these areas. These results suggest that benzodiazepine receptor imaging is superior to regional cerebral blood flow imaging for the detection of viable cortical neurons in both the acute and subacute phases of ischaemia. (orig.)

  17. Pathological features of cerebral cortical capillaries are doubled in Alzheimer’s disease and Parkinson’s disease

    NARCIS (Netherlands)

    Farkas, Eszter; Jong, Gineke I. de; Vos, Rob A.I. de; Jansen Steur, Ernst N.H.; Luiten, Paul G.M.

    2000-01-01

    Cerebral capillaries represent a major interface between the general circulation and the central nervous system and are responsible for sufficient and selective nutrient transport to the brain. Structural damage or dysfunctioning carrier systems of such an active barrier leads to compromised

  18. Point application withAngong Niuhuang sticker protects hippocampal and cortical neurons in rats with cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Dong-shu Zhang; Yuan-liang Liu; Dao-qi Zhu; Xiao-jing Huang; Chao-hua Luo

    2015-01-01

    Angong Niuhuang pill, a Chinese materia medica preparation, can improve neurological func-tions after acute ischemic stroke. Because of its inconvenient application and toxic components (Cinnabaris andRealgar), we used transdermal enhancers to deliverAngong Niuhuang pill by modern technology, which expanded the safe dose range and clinical indications. In this study, Angong Niuhuang stickers administered at different point application doses (1.35, 2.7, and 5.4 g/kg) were administered to theDazhui (DU14), Qihai(RN6) andMingmen (DU4) of rats with chronic cerebral ischemia, for 4 weeks. The Morris water maze was used to determine the learning and memory ability of rats. Hematoxylin-eosin staining and Nissl staining were used to observe neuronal damage of the cortex and hippocampal CA1 region in rats with chronic cerebral ischemia. The middle- and high-dose point application ofAngong Niuhuangstickers attenuated neuronal damage in the cortex and hippocampal CA1 region, and improved the memory of rats with chronic cerebral ischemia with an efifcacy similar to interventions by electroacupuncture at Dazhui (DU14),Qihai (RN6) andMingmen (DU4). Our experimental ifndings indicate that point application withAngong Niuhuang stickers can improve cognitive function after chronic cerebral ischemia in rats and is neuroprotective with an equivalent efifcacy to acupuncture.

  19. Topography of Cortical Microbleeds in Alzheimer's Disease with and without Cerebral Amyloid Angiopathy: A Post-Mortem 7.0-Tesla MRI Study.

    Science.gov (United States)

    De Reuck, J; Auger, F; Durieux, N; Deramecourt, V; Cordonnier, C; Pasquier, F; Maurage, C A; Leys, D; Bordet, R

    2015-11-01

    Cortical microbleeds (CMBs) detected on T2*-weighted gradient-echo (GRE) magnetic resonance imaging (MRI) are considered as a possible hallmark of cerebral amyloid angiopathy (CAA). The present post-mortem 7.0-tesla MRI study investigates whether topographic differences exist in Alzheimer's brains without (AD) and with CAA (AD-CAA). The distribution of CMBs in thirty-two post-mortem brains, consisting of 12 AD, 8 AD-CAA and 12 controls, was mutually compared on T2*-GRE MRI of six coronal sections of a cerebral hemisphere. The mean numbers of CMBs were determined in twenty-two different gyri. As a whole there was a trend of more CMBs on GRE MRI in the prefrontal section of the AD, the AD-CAA as well as of the control brains. Compared to controls AD brains had significantly more CMBs in the superior frontal, the inferior temporal, the rectus and the cinguli gyrus, and in the insular cortex. In AD-CAA brains CMBs were increased in all gyri with exception of the medial parietal gyrus and the hippocampus. AD-CAA brains showed a highly significant increase of CMBs in the inferior parietal gyrus (p value: 0.001) and a significant increase in the precuneus and the cuneus (p value: 0.01) compared to the AD brains. The differences in topographic distribution of CMBs between AD and AD-CAA brains should be further investigated on MRI in clinically suspected patients.

  20. Prefrontal cortical circuit for depression- and anxiety-related behaviors mediated by cholecystokinin: role of ΔFosB.

    Science.gov (United States)

    Vialou, Vincent; Bagot, Rosemary C; Cahill, Michael E; Ferguson, Deveroux; Robison, Alfred J; Dietz, David M; Fallon, Barbara; Mazei-Robison, Michelle; Ku, Stacy M; Harrigan, Eileen; Winstanley, Catherine A; Joshi, Tej; Feng, Jian; Berton, Olivier; Nestler, Eric J

    2014-03-12

    Decreased medial prefrontal cortex (mPFC) neuronal activity is associated with social defeat-induced depression- and anxiety-like behaviors in mice. However, the molecular mechanisms underlying the decreased mPFC activity and its prodepressant role remain unknown. We show here that induction of the transcription factor ΔFosB in mPFC, specifically in the prelimbic (PrL) area, mediates susceptibility to stress. ΔFosB induction in PrL occurred selectively in susceptible mice after chronic social defeat stress, and overexpression of ΔFosB in this region, but not in the nearby infralimbic (IL) area, enhanced stress susceptibility. ΔFosB produced these effects partly through induction of the cholecystokinin (CCK)-B receptor: CCKB blockade in mPFC induces a resilient phenotype, whereas CCK administration into mPFC mimics the anxiogenic- and depressant-like effects of social stress. We previously found that optogenetic stimulation of mPFC neurons in susceptible mice reverses several behavioral abnormalities seen after chronic social defeat stress. Therefore, we hypothesized that optogenetic stimulation of cortical projections would rescue the pathological effects of CCK in mPFC. After CCK infusion in mPFC, we optogenetically stimulated mPFC projections to basolateral amygdala or nucleus accumbens, two subcortical structures involved in mood regulation. Stimulation of corticoamygdala projections blocked the anxiogenic effect of CCK, although no effect was observed on other symptoms of social defeat. Conversely, stimulation of corticoaccumbens projections reversed CCK-induced social avoidance and sucrose preference deficits but not anxiogenic-like effects. Together, these results indicate that social stress-induced behavioral deficits are mediated partly by molecular adaptations in mPFC involving ΔFosB and CCK through cortical projections to distinct subcortical targets.

  1. Endogenous plasma estradiol in healthy men is positively correlated with cerebral cortical serotonin 2A receptor binding

    DEFF Research Database (Denmark)

    Frokjaer, Vibe G.; Erritzoe, David; Juul, Anders;

    2010-01-01

    Background: Sex-hormones influence brain function and are likely to play a role in the gender predisposition to mood and anxiety disorders. Acute fluctuations of sex-hormone levels including hormonal replacement therapy appear to affect serotonergic neurotransmission, but it is unknown if baseline...... = 0.0001), whereas no independent effects of testosterone could be demonstrated. Correction for other factors of importance for 5-HT2A receptor binding did not change the result. A voxel-based analysis suggested that there were no regional differences in the estradiol effect on cortical 5-HT2A...... receptor binding. Conclusions: Our data show a positive correlation between endogenous plasma estradiol levels and cortical 5-HT2A receptor binding in healthy men, whereas, no independent effect of testosterone was demonstrated. We speculate that this association could be mediated through effects on gene...

  2. Object-in-place associative recognition memory depends on glutamate receptor neurotransmission within two defined hippocampal-cortical circuits: a critical role for AMPA and NMDA receptors in the hippocampus, perirhinal, and prefrontal cortices.

    Science.gov (United States)

    Barker, Gareth Robert Issac; Warburton, Elizabeth Clea

    2015-02-01

    Object-in-place associative recognition memory depends on an interaction between the hippocampus (HPC), perirhinal (PRH), and medial prefrontal (mPFC) cortices, yet the contribution of glutamate receptor neurotransmission to these interactions is unknown. NMDA receptors (NMDAR) in the HPC were critical for encoding of object-in-place memory but not for single-item object recognition. Next, a disconnection procedure was used to examine the importance of "concurrent" glutamate neurotransmission in the HPC-mPFC and HPC-PRH. Contralateral unilateral infusions of NBQX (AMPAR antagonist), into the HPC-mPFC, or HPC-PRH, either before acquisition or test, impaired object-in-place performance. Thus, both circuits are necessary for encoding and retrieval. Crossed unilateral AP5 (NMDAR antagonist) infusions into the HPC-mPFC or HPC-PRH impaired encoding, but not retrieval. Specifically crossed HPC-mPFC infusions impaired both short-term (5 min) and longer term (1 h) memory while HPC-PRH infusions impaired longer term memory only. This delay-dependent effect of AP5 in the HPC-PRH on object-in-place memory, accords with its effects in the PRH, on single item object recognition memory, thereby suggesting that a single PRH synaptic plasticity mechanism underpins different recognition memory processes. Further, blocking excitatory neurotransmission in any pair of structures within the networks impaired "both" encoding and retrieval, thus object-in-place memory clearly requires network interdependency across multiple structures.

  3. Inhibitory interneuron circuits at cortical and spinal levels are associated with individual differences in corticomuscular coherence during isometric voluntary contraction

    Science.gov (United States)

    Matsuya, Ryosuke; Ushiyama, Junichi; Ushiba, Junichi

    2017-01-01

    Corticomuscular coherence (CMC) is an oscillatory synchronization of 15–35 Hz (β-band) between electroencephalogram (EEG) of the sensorimotor cortex and electromyogram of contracting muscles. Although we reported that the magnitude of CMC varies among individuals, the physiological mechanisms underlying this variation are still unclear. Here, we aimed to investigate the associations between CMC and intracortical inhibition (ICI) in the primary motor cortex (M1)/recurrent inhibition (RI) in the spinal cord, which probably affect oscillatory neural activities. Firstly, we quantified ICI from changes in motor-evoked potentials induced by paired-pulse transcranial magnetic stimulation in M1 during tonic isometric voluntary contraction of the first dorsal interosseous. ICI showed a significant, negative correlation with the strength of EEG β-oscillation, but not with the magnitude of CMC across individuals. Next, we quantified RI from changes in H-reflexes induced by paired-pulse electrical nerve stimulation to the posterior tibial nerve during isometric contraction of the soleus muscle. We observed a significant, positive correlation between RI and peak CMC across individuals. These results suggest that the local inhibitory interneuron networks in cortical and spinal levels are associated with the oscillatory activity in corticospinal loop. PMID:28290507

  4. Impact of tramadol and morphine abuse on the activities of acetylcholine esterase, Na+/K+-ATPase and related parameters in cerebral cortices of male adult rats.

    Science.gov (United States)

    El-Hamid Mohamed Elwy, Abd; Tabl, Ghada

    2017-03-01

    To determine the effect of the most commonly abused drugs (tramadol and morphine), on acetylcholine esterase (AChE), Na(+)/K(+)-ATPase activities and related parameters, Na(+) and K(+) as biomarkers of neurotoxicity. Tramadol - as a weak μ opioid receptor agonist- and morphine - as opiate analgesic drugs, were chosen for the present study. Four series of experimental animals were conducted for either tramadol or morphine: control series; repeated single equal doses (therapeutic dose) series; cumulative increasing doses series and delay (withdrawal) series (96 hours withdrawal period after last administration), at time period intervals 7, 14 and 21 days. Acetylcholine esterase (AChE), Na(+)/K(+)-ATPase activities and related parameters, Na(+) and K(+) were measured in cerebral cortices of experimental rats. Acetylcholine esterase (AChE) activity in the brain cerebral cortex increased after the administration of therapeutic repeated doses of either tramadol (20 mg/kg b.w.) or morphine (4 mg/kg b.w.) in different groups. The daily intraperitoneal injection of cumulative increasing dose levels of either tramadol 20, 40 and 80 mg/kg or morphine 4, 8 and 12 mg/kg revealed a significant increase in the mean of acetylcholine esterase activities. The withdrawal groups of either tramadol or morphine showed significant decreases in their levels. Na(+)/K(+) ATPase activity in the brain cerebral cortex of either repeated therapeutic doses of tramadol (20 mg/kg) or morphine repeated therapeutic doses (4 mg/kg) for 21 consecutive days at different intervals 7, 14 and 21 days, induced a significant decrease in the levels of Na(+)/K(+)-ATPase in all groups. Withdrawal groups showed a significant decrease in Na(+)/K(+)-ATPase level. Furthermore, the daily intraperitoneal injection of cumulative increasing dose levels of either tramadol (20, 40 and 80 mg/kg b.w.) or morphine (4, 8 and 12 mg/kg b.w.) induced significant decreases in Na(+)/K(+)-ATPase levels in all studied groups

  5. Attention-dependent modulation of cortical taste circuits revealed by Granger causality with signal-dependent noise.

    Directory of Open Access Journals (Sweden)

    Qiang Luo

    2013-10-01

    Full Text Available We show, for the first time, that in cortical areas, for example the insular, orbitofrontal, and lateral prefrontal cortex, there is signal-dependent noise in the fMRI blood-oxygen level dependent (BOLD time series, with the variance of the noise increasing approximately linearly with the square of the signal. Classical Granger causal models are based on autoregressive models with time invariant covariance structure, and thus do not take this signal-dependent noise into account. To address this limitation, here we describe a Granger causal model with signal-dependent noise, and a novel, likelihood ratio test for causal inferences. We apply this approach to the data from an fMRI study to investigate the source of the top-down attentional control of taste intensity and taste pleasantness processing. The Granger causality with signal-dependent noise analysis reveals effects not identified by classical Granger causal analysis. In particular, there is a top-down effect from the posterior lateral prefrontal cortex to the insular taste cortex during attention to intensity but not to pleasantness, and there is a top-down effect from the anterior and posterior lateral prefrontal cortex to the orbitofrontal cortex during attention to pleasantness but not to intensity. In addition, there is stronger forward effective connectivity from the insular taste cortex to the orbitofrontal cortex during attention to pleasantness than during attention to intensity. These findings indicate the importance of explicitly modeling signal-dependent noise in functional neuroimaging, and reveal some of the processes involved in a biased activation theory of selective attention.

  6. Computational modelling of the cerebral cortical microvasculature: effect of x-ray microbeams versus broad beam irradiation

    Science.gov (United States)

    Merrem, A.; Bartzsch, S.; Laissue, J.; Oelfke, U.

    2017-05-01

    Microbeam Radiation Therapy is an innovative pre-clinical strategy which uses arrays of parallel, tens of micrometres wide kilo-voltage photon beams to treat tumours. These x-ray beams are typically generated on a synchrotron source. It was shown that these beam geometries allow exceptional normal tissue sparing from radiation damage while still being effective in tumour ablation. A final biological explanation for this enhanced therapeutic ratio has still not been found, some experimental data support an important role of the vasculature. In this work, the effect of microbeams on a normal microvascular network of the cerebral cortex was assessed in computer simulations and compared to the effect of homogeneous, seamless exposures at equal energy absorption. The anatomy of a cerebral microvascular network and the inflicted radiation damage were simulated to closely mimic experimental data using a novel probabilistic model of radiation damage to blood vessels. It was found that the spatial dose fractionation by microbeam arrays significantly decreased the vascular damage. The higher the peak-to-valley dose ratio, the more pronounced the sparing effect. Simulations of the radiation damage as a function of morphological parameters of the vascular network demonstrated that the distribution of blood vessel radii is a key parameter determining both the overall radiation damage of the vasculature and the dose-dependent differential effect of microbeam irradiation.

  7. Regulation of Extrasynaptic GABAA α4 Receptors by Ethanol-Induced Protein Kinase A, but Not Protein Kinase C Activation in Cultured Rat Cerebral Cortical Neurons.

    Science.gov (United States)

    Carlson, Stephen L; Bohnsack, J Peyton; Patel, Vraj; Morrow, A Leslie

    2016-01-01

    Ethanol produces changes in GABAA receptor trafficking and function that contribute to ethanol dependence symptomatology. Extrasynaptic γ-aminobutyric acid A receptors (GABAA-R) mediate inhibitory tonic current and are of particular interest because they are potentiated by physiologically relevant doses of ethanol. Here, we isolate GABAA α4δ receptors by western blotting in subsynaptic fractions to investigate protein kinase A (PKA) and protein kinase C (PKC) modulation of ethanol-induced receptor trafficking, while extrasynaptic receptor function is determined by measurement of tonic inhibition and responses evoked by 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP). Rat cerebral cortical neurons were grown for 18 days in vitro and exposed to ethanol and/or PKA/PKC modulators. Ethanol exposure (1 hour) did not alter GABAA α4 receptor abundance, but it increased tonic current amplitude, an effect that was prevented by inhibiting PKA, but not PKC. Direct activation of PKA, but not PKC, increased the abundance and tonic current of extrasynaptic α4δ receptors. In contrast, prolonged ethanol exposure (4 hours) reduced α4δ receptor abundance as well as tonic current, and this effect was also PKA dependent. Finally, PKC activation by ethanol or phorbol-12,13-dibutyrate (PdBu) had no effect on extrasynaptic α4δ subunit abundance or activity. We conclude that ethanol alters extrasynaptic α4δ receptor function and expression in cortical neurons in a PKA-dependent manner, but ethanol activation of PKC does not influence these receptors. These results could have clinical relevance for therapeutic strategies to restore normal GABAergic functioning for the treatment of alcohol use disorders.

  8. Nrdp1 Increases Ischemia Induced Primary Rat Cerebral Cortical Neurons and Pheochromocytoma Cells Apoptosis Via Downregulation of HIF-1α Protein

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    2017-09-01

    Full Text Available Neuregulin receptor degradation protein-1 (Nrdp1 is an E3 ubiquitin ligase that targets proteins for degradation and regulates cell growth, apoptosis and oxidative stress in various cell types. We have previously shown that Nrdp1 is implicated in ischemic cardiomyocyte death. In this study, we investigated the change of Nrdp1 expression in ischemic neurons and its role in ischemic neuronal injury. Primary rat cerebral cortical neurons and pheochromocytoma (PC12 cells were infected with adenoviral constructs expressing Nrdp1 gene or its siRNA before exposing to oxygen-glucose deprivation (OGD treatment. Our data showed that Nrdp1 was upregulated in ischemic brain tissue 3 h after middle cerebral artery occlusion (MCAO and in OGD-treated neurons. Of note, Nrdp1 overexpression by Ad-Nrdp1 enhanced OGD-induced neuron apoptosis, while knockdown of Nrdp1 with siRNA attenuated this effect, implicating a role of Nrdp1 in ischemic neuron injury. Moreover, Nrdp1 upregulation is accompanied by increased protein ubiquitylation and decreased protein levels of ubiquitin-specific protease 8 (USP8 in OGD-treated neurons, which led to a suppressed interaction between USP8 and HIF-1α and subsequently a reduction in HIF-1α protein accumulation in neurons under OGD conditions. In conclusion, our data support an important role of Nrdp1 upregulation in ischemic neuronal death, and suppressing the interaction between USP8 and HIF-1α and consequently the hypoxic adaptive response of neurons may account for this detrimental effect.

  9. FNIRS-based evaluation of cortical plasticity in children with cerebral palsy undergoing constraint-induced movement therapy

    Science.gov (United States)

    Cao, Jianwei; Khan, Bilal; Hervey, Nathan; Tian, Fenghua; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Roberts, Heather; Tulchin-Francis, Kirsten; Shierk, Angela; Shagman, Laura; MacFarlane, Duncan; Liu, Hanli; Alexandrakis, George

    2015-03-01

    Sensorimotor cortex plasticity induced by constraint-induced movement therapy (CIMT) in six children (10.2 ± 2.1 years old) with hemiplegic cerebral palsy (CP) was assessed by functional near-infrared spectroscopy (fNIRS). The activation laterality index and time-to-peak/duration during a finger tapping task were quantified before, immediately after, and six months after CIMT. Five age-matched healthy children (9.8 ± 1.3 years old) were also imaged at the same time points to provide comparative activation metrics for normal controls. In children with CP the activation time-to-peak/duration for all sensorimotor centers displayed significant normalization immediately after CIMT that persisted six months later. In contrast to this longer term improvement in localized activation response, the laterality index that depended on communication between sensorimotor centers improved immediately after CIMT, but relapsed six months later.

  10. The contribution of alcohol, thiamine deficiency and cirrhosis of the liver to cerebral cortical damage in alcoholics.

    Science.gov (United States)

    Kril, J J

    1995-03-01

    The relative roles of alcohol toxicity, thiamine deficiency and cirrhosis of the liver in the pathogenesis of alcohol-related brain damage are unclear. Brain shrinkage and neuronal loss from four regions of the cortex was determined in 22 alcoholics with the Wernicke-Korsakoff Syndrome (WKS), cirrhosis of the liver or neither of these complications and compared to 22 age-matched non-alcoholic controls. Brain shrinkage was most marked in those alcoholics with WKS. Neuronal loss occurred only from the superior cortex and was of equal magnitude in all alcoholic subgroups. In an animal model of alcohol abuse and thiamine deficiency, neuronal loss from the cerebral cortex occurred in a time-dependent manner. Furthermore, those cells which contained the calcium-binding protein parvalbumin appeared to be preferentially damaged in this model.

  11. Electro-acupuncture exerts beneficial effects against cerebral ischemia and promotes the proliferation of neural progenitor cells in the cortical peri-infarct area through the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Chen, Bin; Tao, Jing; Lin, Yukun; Lin, Ruhui; Liu, Weilin; Chen, Lidian

    2015-11-01

    Electro-acupuncture (EA) is a novel therapy based on combining traditional acupuncture with modern electrotherapy, and it is currently being investigated as a treatment for ischemic stroke. In the present study, we aimed to investigate the mechanisms through which EA regulates the proliferation of neural progenitor cells (NPCs) in the cortical peri‑infarct area after stroke. The neuroprotective effects of EA on ischemic rats were evaluated by determining the neurological deficit scores and cerebral infarct volumes. The proliferation of the NPCs and the activation of the Wnt/β‑catenin signaling pathway in the cortical peri‑infarct area were examined. Our results revealed that EA significantly alleviated neurological deficits, reduced the infarct volume and enhanced NPC proliferation [nestin/glial fibrillary acidic protein (GFAP)‑double positive] in the cortex of rats subjected to middle cerebral artery occlusion (MCAO). Moreover, the Wnt1 and β‑catenin mRNA and protein levels were increased, while glycogen synthase kinase‑3 (GSK3) transcription was suppressed by EA. These results suggest that the upregulatory effects of EA on the Wnt/β‑catenin signaling pathway may promote NPC proliferation in the cortical peri-infarct area after stroke, consequently providing a therapeutic effect against cerebral ischemia.

  12. Storing maternal memories: hypothesizing an interaction of experience and estrogen on sensory cortical plasticity to learn infant cues.

    Science.gov (United States)

    Banerjee, Sunayana B; Liu, Robert C

    2013-10-01

    Much of the literature on maternal behavior has focused on the role of infant experience and hormones in a canonical subcortical circuit for maternal motivation and maternal memory. Although early studies demonstrated that the cerebral cortex also plays a significant role in maternal behaviors, little has been done to explore what that role may be. Recent work though has provided evidence that the cortex, particularly sensory cortices, contains correlates of sensory memories of infant cues, consistent with classical studies of experience-dependent sensory cortical plasticity in non-maternal paradigms. By reviewing the literature from both the maternal behavior and sensory cortical plasticity fields, focusing on the auditory modality, we hypothesize that maternal hormones (predominantly estrogen) may act to prime auditory cortical neurons for a longer-lasting neural trace of infant vocal cues, thereby facilitating recognition and discrimination. This couldthen more efficiently activate the subcortical circuit to elicit and sustain maternal behavior.

  13. The calmodulin-dependent protein kinase II inhibitor KN-93 protects rat cerebral cortical neurons from N-methyl-D-aspartic acid-induced injury

    Institute of Scientific and Technical Information of China (English)

    Xuewen Liu; Cui Ma; Ruixian Xing; Weiwei Zhang; Buxian Tian; Xidong Li; Qiushi Li; Yanhui Zhang

    2013-01-01

    In this study, primary cultured cerebral cortical neurons of Sprague-Dawley neonatal rats were treated with 0.25, 0.5, and 1.0 μM calmodulin-dependent protein kinase II inhibitor KN-93 after 50 μM N-methyl-D-aspartic acid-induced injury. Results showed that, compared with N-methyl-Daspartic acid-induced injury neurons, the activity of cells markedly increased, apoptosis was significantly reduced, leakage of lactate dehydrogenase decreased, and intracellular Ca2+ concentrations in neurons reduced after KN-93 treatment. The expression of caspase-3, phosphorylated calmodulin-dependent protein kinase II and total calmodulin-dependent protein kinase II protein decreased after KN-93 treatment. And the effect was apparent at a dose of 1.0 μM KN-93. Experimental findings suggest that KN-93 can induce a dose-dependent neuroprotective effect, and that the underlying mechanism may be related to the down-regulation of caspase-3 and calmodulin- dependent protein kinase II expression.

  14. l-Citrulline ameliorates cerebral blood flow during cortical spreading depression in rats: Involvement of nitric oxide- and prostanoids-mediated pathway.

    Science.gov (United States)

    Kurauchi, Yuki; Mokudai, Koichi; Mori, Asami; Sakamoto, Kenji; Nakahara, Tsutomu; Morita, Masahiko; Kamimura, Ayako; Ishii, Kunio

    2017-02-17

    l-Citrulline is a potent precursor of l-arginine, and exerts beneficial effect on cardiovascular system via nitric oxide (NO) production. Migraine is one of the most popular neurovascular disorder, and imbalance of cerebral blood flow (CBF) observed in cortical spreading depression (CSD) contributes to the mechanism of migraine aura. Here, we investigated the effect of l-citrulline on cardiovascular changes to KCl-induced CSD. in rats. Intravenous injection of l-citrulline prevented the decrease in CBF, monitored by laser Doppler flowmetry, without affecting mean arterial pressure and heart rate during CSD. Moreover, l-citrulline attenuated propagation velocity of CSD induced by KCl. The effect of l-citrulline on CBF change was prevented by l-NAME, an inhibitor of NO synthase, but not by indomethacin, an inhibitor of cyclooxygenase. On the other hand, attenuation effect of l-citrulline on CSD propagation velocity was prevented not only by l-NAME but also by indomethacin. In addition, propagation velocity of CSD was attenuated by intravenous injection of NOR3, a NO donor, which was diminished by ODQ, an inhibitor of soluble guanylyl cyclase. These results suggest that NO/cyclic GMP- and prostanoids-mediated pathway differently contribute to the effect of l-citrulline on the maintenance of CBF.

  15. Effect of electrical stimulation therapy on upper extremity functional recovery and cerebral cortical changes in patients with chronic hemiplegia.

    Science.gov (United States)

    Sasaki, Kana; Matsunaga, Toshiki; Tomite, Takenori; Yoshikawa, Takayuki; Shimada, Yoichi

    2012-04-01

    Hemiplegia is a common sequel of stroke and assisted living care is needed in many cases. The purpose of this study was to evaluate the effect of using surface electrode stimulation device in rehabilitation, in terms of functional improvement in upper limb and the changes in brain activation related to central nervous system reconstruction. Five patients with chronic hemiplegia received electrical stimulation therapy using the orthosis-type surface electrode stimulation device for 12 weeks. Training time was 30 min/day for the first weeks, and increased 30 min/day in every 4 weeks. Upper limb outcome measures included Brunnstrom stage, range of motion, Fugl-Meyer assessment and manual function test. Brain activation was measured using functional MRI. After therapy with therapeutic electrical stimulation (TES) for 12 weeks upper limb function improved in all cases. The results of brain activation showed two patterns. In the first, the stimulation produced an activity in the bilateral somatosensory cortices (SMC), which was seen to continue over time. The second, activation was bilateral and extensive before stimulation, but localized to the SMC after intervention. Treatment with TES using an orthosis-type electrode stimulation device improves upper limb function in chronic hemiplegia patients. The present findings suggest that there are not only efferent but also afferent effects that may promote central nervous system remodeling.

  16. Dor central devida a compressão do cortex parietal por tumor cerebral: relato de dois casos Central pain from cerebral cortical parietal tumors: report of two cases

    Directory of Open Access Journals (Sweden)

    Edson José Amâncio

    2002-06-01

    Full Text Available Dor central produzida por tumores cerebrais é considerada rara pela maioria dos autores. Os poucos casos descritos na literatura fazem referência à dor central provocada pela presença de lesões expansivas acometendo o córtex parietal contralateral. Nem mesmo os tumores talâmicos costumam produzir dor central. Apresentamos dois casos de dor central associada a lesões expansivas que acometeram o córtex parietal, 1 astrocitoma low grade e 1 meningioma. Em ambos houve alívio da dor após a remoção cirúrgica das lesões.Central pain derived from cerebral tumors is considered rare by most authors. The few cases described in literature refer to central pain caused by expansive lesions in the contralatral parietal cortex. Usually, not even thalamic tumors cause central pain. We describe two cases of central pain related to expansive lesions in the parietal cortical region -- a low grade astrocytoma and a meningioma. Both patients reported pain relief after lesions were removed by surgery.

  17. Early involvement of lysosome dysfunction in the degeneration of cerebral cortical neurons caused by the lipid peroxidation product 4-hydroxynonenal.

    Science.gov (United States)

    Zhang, Shi; Eitan, Erez; Mattson, Mark P

    2017-03-01

    Free radical-mediated oxidative damage to proteins, lipids, and DNA occurs in neurons during acute brain injuries and in neurodegenerative disorders. Membrane lipid peroxidation contributes to neuronal dysfunction and death, in part by disrupting neuronal ion homeostasis and cellular bioenergetics. Emerging findings suggest that 4-hydroxynonenal (HNE), an aldehyde produced during lipid peroxidation, impairs the function of various proteins involved in neuronal homeostasis. Here we tested the hypothesis that HNE impairs the cellular system that removes damaged proteins and organelles, the autophagy-lysosome pathway in rat primary cortical neurons. We found that HNE, at a concentration that causes apoptosis over a 48-72 h period, increases protein levels of LC3 II and p62 and within 1 and 4 h of exposure, respectively; LC3 II and p62 immunoreactive puncta were observed in the cytoplasm of HNE-treated neurons at 6 h. The extent of up-regulation of p62 and LC3 II in response to HNE was not affected by co-treatment with the lysosome inhibitor bafilomycin A1, suggesting that the effects of HNE on autophagy were secondary to lysosome inhibition. Indeed, we found that neurons exposed to HNE exhibit elevated pH levels, and decreased protein substrate hydrolysis and cathepsin B activity. Neurons exposed to HNE also exhibited the accumulation of K63-linked polyubiquitinated proteins, which are substrates targeted for lysosomal degradation. Moreover, we found that the levels of LAMP2a and constitutively active heat-shock protein 70, and numbers of LAMP2a-positive lysosomes, are decreased in neurons exposed to HNE. Our findings demonstrate that the lipid peroxidation product HNE causes early impairment of lysosomes which may contribute to the accumulation of damaged and dysfunctional proteins and organelles and consequent neuronal death. Because impaired lysosome function is increasingly recognized as an early event in the neuronal death that occurs in neurodegenerative

  18. Long-term sensory stimulation therapy improves hand function and restores cortical responsiveness in patients with chronic cerebral lesions. Three single case studies.

    Directory of Open Access Journals (Sweden)

    Jan-Christoph eKattenstroth

    2012-08-01

    Full Text Available Rehabilitation of sensorimotor impairment resulting from cerebral lesion (CL utilizes task specific training and massed practice to drive reorganization and sensorimotor improvement due to induction of neuroplasticity mechanisms. Loss of sensory abilities often complicates recovery, and thus the individual’s ability to use the affected body part for functional tasks. Therefore, the development of additional and alternative approaches that supplement, enhance, or even replace conventional training procedures would be advantageous. Repetitive sensory stimulation protocols (rSS have been shown to evoke sensorimotor improvements of the affected limb in patients with chronic stroke. However, the possible impact of long-term rSS on sensorimotor performance of patients with CL, where the incident dated back many years remains unclear. The particular advantage of rSS is its passive nature, which does not require active participation of the subjects. Therefore, rSS can be applied parallel to other occupations, making the intervention easier to implement and more acceptable to the individual. Here we report the effects of applying rSS for 8, 36 and 76 weeks on the paretic hand of 3 long-term patients with different types of CL. Different behavioral tests were used to assess sensory and/or sensorimotor performance of the upper extremities prior, after, and during the intervention. In one patient, the impact of long-term rSS on restoration of cortical activation was investigated by recording somatosensory evoked potentials. After long-term rSS all three patients showed considerable improvements of their sensory and motor abilities. In addition, almost normal evoked potentials could be recorded after rSS in one patient. Our data show that long-term rSS applied to patients with chronic CL can improve tactile and sensorimotor functions, which, however, developed in some cases only after many weeks of stimulation, and continued to further improve on a time

  19. 脑血管介入术后皮质盲的临床分析%Acute transient cortical blindness occurring after cerebral angiography and vascular interventional management: a clinical analysis

    Institute of Scientific and Technical Information of China (English)

    江泓; 杨文洁; 胡锦清; 顾俊伟; 张伟华; 杨燕敏; 沈建康; 林东

    2013-01-01

    Objective To discuss the diagnosis, the possible etiologic factors and the corresponding prevention measures of the cortical blindness that occurs after cerebral angiography and vascular interventional management. Methods During the period from August 2007 to August 2012, cerebral angiography and vascular interventional management were carries out in 2 547 patients. Among the 2 547 cases, postoperative cortical blindness occurred in 8 cases. The clinical data were analyzed. Results After cerebral angiography and vascular interventional management, 8 cases developed transient cortical blindness, and the mean amount of contrast medium used in the performance of cerebral angiography and intervention was 107 ml. After medication the clinical symptoms disappeared completely, and all the patients recovered well. Conclusion In order to reduce the occurrence of cortical blindness after cerebral angiography and intervention, it is necessary to reduce the operation time, to employ non-ionic contrast medium and to use the contrast medium as little as possible.(J Intervent Radiol, 2013, 22: 008-011)%目的 探讨脑血管造影和介入治疗术后一过性皮质盲的诊断、可能的病因及预防措施.方法 2007年8月至2012年8月对2547例患者行脑血管造影和介入治疗,筛选出术后出现皮质盲的患者共8例次,并对患者的临床资料进行分析.结果 行脑血管造影和介入治疗共2547例患者,其中8例次术后出现了一过性皮质盲,平均对比剂用量107 ml.所有患者经治疗后症状消失,预后良好.结论 为了减少造影术后皮质盲发生率,应尽量减少造影时间,常规使用非离子型对比剂,降低对比剂使用总量.

  20. Clinical analysis and review of the literature of cortical blindness after cerebral angiography%脑血管介入诊疗术后致皮质盲的临床分析

    Institute of Scientific and Technical Information of China (English)

    李建涛; 孙学东; 李生; 肖玉良; 王君

    2015-01-01

    Objective:To analyze the pathogeny of the cortical blindness caused by cerebral angiography. Methods:The analysis was made of the clinical data of the 4 case of postoperative cortical blindness from 5965 cases of the cerebral angi-ography during from January 2008 to December 2014. Results:No pathologies were found,and cranial computed tomo-graphy showed no intracranial infarcts and hemorrhage in the ophthalmologic and neurologic examination. Treatment includ-ed the alleviation of vasospasm,improvement of cerebral perfusion pressure,stable blood brain barrier and neural nutrition, improvement of cerebral metabolism,free radical scavenging and psychological counseling symptomatic treatment. Four pa-tients with cortical blindness were recovered in 11 days. There were related complications in the 3 follow-up months. Con-clusion:The cortical blindness,caused by cerebral angiography,is a rare complication,and most patients can be cured.%目的:讨论血管造影和/或介入治疗术后皮质盲的病因、诊断、治疗和预防措施。方法回顾性分析我科5965例脑血管介入诊疗患者中,以皮质盲为主要表现的4例患者的病史、检查过程、术后症状表现、治疗方法、相关辅助检查资料、治疗结果。结果患者神经眼科检查未见异常,颅脑CT均未见明显颅内埂塞和出血表现。经过扩容、缓解血管痉挛、改善脑灌注压、稳定血脑屏障、神经营养、改善脑代谢、清除自由基以及心理疏导等对症治疗,4例患者皮质盲在11天内完全恢复,随访3个月未见相关并发症。结论数字减影血管造影术( DSA)术后皮质盲是少见并发症,但经过对症处理,多数预后良好;工作中应提高认识,降低发生率。

  1. Cortical Lewy Body Dementia

    Directory of Open Access Journals (Sweden)

    W. R. G. Gibb

    1990-01-01

    Full Text Available In cortical Lewy body dementia the distribution of Lewy bodies in the nervous system follows that of Parkinson's disease, except for their greater profusion in the cerebral cortex. The cortical tangles and plaques of Alzheimer pathology are often present, the likely explanation being that Alzheimer pathology provokes dementia in many patients. Pure cortical Lewy body dementia without Alzheimer pathology is uncommon. The age of onset reflects that of Parkinson's disease, and clinical features, though not diagnostic, include aphasias, apraxias, agnosias, paranoid delusions and visual hallucinations. Parkinsonism may present before or after the dementia, and survival duration is approximately half that seen in Parkinson's disease without dementia.

  2. Negative Correlations in Visual Cortical Networks

    National Research Council Canada - National Science Library

    Chelaru, Mircea I; Dragoi, Valentin

    2016-01-01

    .... Whereas positive noise correlations have been extensively studied using experimental and theoretical tools, the functional role of negative correlations in cortical circuits has remained elusive...

  3. Storing maternal memories: Hypothesizing an interaction of experience and estrogen on sensory cortical plasticity to learn infant cues

    OpenAIRE

    Banerjee, Sunayana B.; Liu, Robert C.

    2013-01-01

    Much of the literature on maternal behavior has focused on the role of infant experience and hormones in a canonical subcortical circuit for maternal motivation and maternal memory. Although early studies demonstrated that the cerebral cortex also plays a significant role in maternal behaviors, little has been done to explore what that role may be. Recent work though has provided evidence that the cortex, particularly sensory cortices, contains correlates of sensory memories of infant cues, c...

  4. Adolescent brain maturation and cortical folding: evidence for reductions in gyrification.

    Directory of Open Access Journals (Sweden)

    Daniel Klein

    Full Text Available Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM, increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla magnetic resonance imaging (MRI data from 79 healthy subjects (34 males and 45 females between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI. In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development.

  5. Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality.

    Directory of Open Access Journals (Sweden)

    Shree Hari Gautam

    2015-12-01

    Full Text Available Modulation of interactions among neurons can manifest as dramatic changes in the state of population dynamics in cerebral cortex. How such transitions in cortical state impact the information processing performed by cortical circuits is not clear. Here we performed experiments and computational modeling to determine how somatosensory dynamic range depends on cortical state. We used microelectrode arrays to record ongoing and whisker stimulus-evoked population spiking activity in somatosensory cortex of urethane anesthetized rats. We observed a continuum of different cortical states; at one extreme population activity exhibited small scale variability and was weakly correlated, the other extreme had large scale fluctuations and strong correlations. In experiments, shifts along the continuum often occurred naturally, without direct manipulation. In addition, in both the experiment and the model we directly tuned the cortical state by manipulating inhibitory synaptic interactions. Our principal finding was that somatosensory dynamic range was maximized in a specific cortical state, called criticality, near the tipping point midway between the ends of the continuum. The optimal cortical state was uniquely characterized by scale-free ongoing population dynamics and moderate correlations, in line with theoretical predictions about criticality. However, to reproduce our experimental findings, we found that existing theory required modifications which account for activity-dependent depression. In conclusion, our experiments indicate that in vivo sensory dynamic range is maximized near criticality and our model revealed an unanticipated role for activity-dependent depression in this basic principle of cortical function.

  6. Maximizing Sensory Dynamic Range by Tuning the Cortical State to Criticality

    Science.gov (United States)

    Gautam, Shree Hari; Hoang, Thanh T.; McClanahan, Kylie; Grady, Stephen K.; Shew, Woodrow L.

    2015-01-01

    Modulation of interactions among neurons can manifest as dramatic changes in the state of population dynamics in cerebral cortex. How such transitions in cortical state impact the information processing performed by cortical circuits is not clear. Here we performed experiments and computational modeling to determine how somatosensory dynamic range depends on cortical state. We used microelectrode arrays to record ongoing and whisker stimulus-evoked population spiking activity in somatosensory cortex of urethane anesthetized rats. We observed a continuum of different cortical states; at one extreme population activity exhibited small scale variability and was weakly correlated, the other extreme had large scale fluctuations and strong correlations. In experiments, shifts along the continuum often occurred naturally, without direct manipulation. In addition, in both the experiment and the model we directly tuned the cortical state by manipulating inhibitory synaptic interactions. Our principal finding was that somatosensory dynamic range was maximized in a specific cortical state, called criticality, near the tipping point midway between the ends of the continuum. The optimal cortical state was uniquely characterized by scale-free ongoing population dynamics and moderate correlations, in line with theoretical predictions about criticality. However, to reproduce our experimental findings, we found that existing theory required modifications which account for activity-dependent depression. In conclusion, our experiments indicate that in vivo sensory dynamic range is maximized near criticality and our model revealed an unanticipated role for activity-dependent depression in this basic principle of cortical function. PMID:26623645

  7. The Effects of Different Repetitive Transcranial Magnetic Stimulation (rTMS) Protocols on Cortical Gene Expression in a Rat Model of Cerebral Ischemic-Reperfusion Injury.

    Science.gov (United States)

    Ljubisavljevic, Milos R; Javid, Asma; Oommen, Joji; Parekh, Khatija; Nagelkerke, Nico; Shehab, Safa; Adrian, Thomas E

    2015-01-01

    Although repetitive Transcranial Magnetic Stimulation (rTMS) in treatment of stroke in humans has been explored over the past decade the data remain controversial in terms of optimal stimulation parameters and the mechanisms of rTMS long-term effects. This study aimed to explore the potential of different rTMS protocols to induce changes in gene expression in rat cortices after acute ischemic-reperfusion brain injury. The stroke was induced by middle cerebral artery occlusion (MCAO) with subsequent reperfusion. Changes in the expression of 96 genes were examined using low-density expression arrays after MCAO alone and after MCAO combined with 1Hz, 5Hz, continuous (cTBS) and intermittent (iTBS) theta-burst rTMS. rTMS over the lesioned hemisphere was given for two weeks (with a 2-day pause) in a single daily session and a total of 2400 pulses. MCAO alone induced significant upregulation in the expression of 44 genes and downregulation in 10. Two weeks of iTBS induced significant increase in the expression of 52 genes. There were no downregulated genes. 1Hz and 5Hz had no significant effects on gene expression, while cTBS effects were negligible. Upregulated genes included those involved in angiogenesis, inflammation, injury response and cellular repair, structural remodeling, neuroprotection, neurotransmission and neuronal plasticity. The results show that long-term rTMS in acute ischemic-reperfusion brain injury induces complex changes in gene expression that span multiple pathways, which generally promote the recovery. They also demonstrate that induced changes primarily depend on the rTMS frequency (1Hz and 5Hz vs. iTBS) and pattern (cTBS vs. iTBS). The results further underlines the premise that one of the benefits of rTMS application in stroke may be to prime the brain, enhancing its potential to cope with the injury and to rewire. This could further augment its potential to favorably respond to rehabilitation, and to restore some of the loss functions.

  8. Differences in the mechanical properties of the developing cerebral cortical proliferative zone between mice and ferrets at both the tissue and single-cell levels

    Directory of Open Access Journals (Sweden)

    Arata Nagasaka

    2016-11-01

    Full Text Available Cell-producing events in developing tissues are mechanically dynamic throughout the cell cycle. In many epithelial systems, cells are apicobasally tall, with nuclei and somata that adopt different apicobasal positions because nuclei and somata move in a cell cycle–dependent manner. This movement is apical during G2 phase and basal during G1 phase, whereas mitosis occurs at the apical surface. These movements are collectively referred to as interkinetic nuclear migration, and such epithelia are called pseudostratified. The embryonic mammalian cerebral cortical neuroepithelium is a good model for highly pseudostratified epithelia, and we previously found differences between mice and ferrets in both horizontal cellular density (greater in ferrets and nuclear/somal movements (slower during G2 and faster during G1 in ferrets. These differences suggest that neuroepithelial cells alter their nucleokinetic behavior in response to physical factors that they encounter, which may form the basis for evolutionary transitions towards more abundant brain-cell production from mice to ferrets and primates. To address how mouse and ferret neuroepithelia may differ physically in a quantitative manner, we used atomic force microscopy to determine that the vertical stiffness of their apical surface is greater in ferrets (Young’s modulus = 1700 Pa than in mice (1400 Pa. We systematically analyzed factors underlying the apical-surface stiffness through experiments to pharmacologically inhibit actomyosin or microtubules and to examine recoiling behaviors of the apical surface upon laser ablation and also through electron microscopy to observe adherens junction. We found that although both actomyosin and microtubules are partly responsible for the apical-surface stiffness, the mouse

  9. The Effects of Different Repetitive Transcranial Magnetic Stimulation (rTMS Protocols on Cortical Gene Expression in a Rat Model of Cerebral Ischemic-Reperfusion Injury.

    Directory of Open Access Journals (Sweden)

    Milos R Ljubisavljevic

    Full Text Available Although repetitive Transcranial Magnetic Stimulation (rTMS in treatment of stroke in humans has been explored over the past decade the data remain controversial in terms of optimal stimulation parameters and the mechanisms of rTMS long-term effects. This study aimed to explore the potential of different rTMS protocols to induce changes in gene expression in rat cortices after acute ischemic-reperfusion brain injury. The stroke was induced by middle cerebral artery occlusion (MCAO with subsequent reperfusion. Changes in the expression of 96 genes were examined using low-density expression arrays after MCAO alone and after MCAO combined with 1Hz, 5Hz, continuous (cTBS and intermittent (iTBS theta-burst rTMS. rTMS over the lesioned hemisphere was given for two weeks (with a 2-day pause in a single daily session and a total of 2400 pulses. MCAO alone induced significant upregulation in the expression of 44 genes and downregulation in 10. Two weeks of iTBS induced significant increase in the expression of 52 genes. There were no downregulated genes. 1Hz and 5Hz had no significant effects on gene expression, while cTBS effects were negligible. Upregulated genes included those involved in angiogenesis, inflammation, injury response and cellular repair, structural remodeling, neuroprotection, neurotransmission and neuronal plasticity. The results show that long-term rTMS in acute ischemic-reperfusion brain injury induces complex changes in gene expression that span multiple pathways, which generally promote the recovery. They also demonstrate that induced changes primarily depend on the rTMS frequency (1Hz and 5Hz vs. iTBS and pattern (cTBS vs. iTBS. The results further underlines the premise that one of the benefits of rTMS application in stroke may be to prime the brain, enhancing its potential to cope with the injury and to rewire. This could further augment its potential to favorably respond to rehabilitation, and to restore some of the loss

  10. Modulation of carbachol-stimulated inositol phospholipid breakdown in rat cerebral cortical miniprisms at excitatory amino acids and by BAY K-8644 is dependent upon the assay calcium and potassium concentrations used

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    Tiger, G. (Univ. of Umea (Sweden)); Fowler, C.J. (Astra Research Centre, Soedertalje (Sweden))

    1991-01-01

    The calcium and potassium ion dependency of the inositol phospholipid breakdown response to stimulatory agents has been investigated in rat cerebral cortical miniprisms. The calcium channel agonist BAY K-8644 potentiated the response to carbachol at 6 mM K{sup +} when Ca{sup 2+}-free, but not when 2.52 mM Ca{sup 2+} assay buffer was used. In Ca{sup 2+}-free buffer, verapamil inhibited the response to carbachol at both 6 and 18 mM K{sup +} but higher concentrations were needed when 2.52 mM Ca{sup 2+} was used. At these higher concentrations, however, verapamil inhibited the binding of 2 nM ({sup 3}H)pirenzepine to muscarinic recognition sites. N-Methyl-D-Aspartate (NMDA) significantly reduced the basal phosphoinositide breakdown rate at 18 mM K{sup +} at 1.3 mM Ca{sup 2+}, but was without effect on the basal rate at other K{sup +} and Ca{sup 2+} concentrations. In the presence of NMDA or quisqualate, the responses to carbachol were reduced, the degree of reduction showing a complex dependency upon the assay K{sup +} and Ca{sup 2+} concentrations used. These results indicate that the inositol phospholipid breakdown response to carbachol in cerebral cortical miniprisms can be modulated in a manner dependent upon the extracellular calcium and potassium concentrations used.

  11. Early GABAergic circuitry in the cerebral cortex.

    Science.gov (United States)

    Luhmann, Heiko J; Kirischuk, Sergei; Sinning, Anne; Kilb, Werner

    2014-06-01

    In the cerebral cortex GABAergic signaling plays an important role in regulating early developmental processes, for example, neurogenesis, migration and differentiation. Transient cell populations, namely Cajal-Retzius in the marginal zone and thalamic input receiving subplate neurons, are integrated as active elements in transitory GABAergic circuits. Although immature pyramidal neurons receive GABAergic synaptic inputs already at fetal stages, they are integrated into functional GABAergic circuits only several days later. In consequence, GABAergic synaptic transmission has only a minor influence on spontaneous network activity during early corticogenesis. Concurrent with the gradual developmental shift of GABA action from excitatory to inhibitory and the maturation of cortical synaptic connections, GABA becomes more important in synchronizing neuronal network activity.

  12. Computational modeling of stuttering caused by impairments in a basal ganglia thalamo-cortical circuit involved in syllable selection and initiation

    Science.gov (United States)

    Civier, Oren; Bullock, Daniel; Max, Ludo; Guenther, Frank H.

    2013-01-01

    A typical white-matter integrity and elevated dopamine levels have been reported for individuals who stutter. We investigated how such abnormalities may lead to speech dysfluencies due to their effects on a syllable-sequencing circuit that consists of basal ganglia (BG), thalamus, and left ventral premotor cortex (vPMC). “Neurally impaired” versions of the neurocomputational speech production model GODIVA were utilized to test two hypotheses: (1) that white-matter abnormalities disturb the circuit via corticostriatal projections carrying copies of executed motor commands, and (2) that dopaminergic abnormalities disturb the circuit via the striatum. Simulation results support both hypotheses: in both scenarios, the neural abnormalities delay readout of the next syllable’s motor program, leading to dysfluency. The results also account for brain imaging findings during dysfluent speech. It is concluded that each of the two abnormality types can cause stuttering moments, probably by affecting the same BG-thalamus-vPMC circuit. PMID:23872286

  13. A compact and realistic cerebral cortical layout derived from prewhitened resting-state fMRI time series: Cherniak’s adjacency rule, size law and metamodule grouping upheld

    Directory of Open Access Journals (Sweden)

    Scott M Lewis

    2012-09-01

    Full Text Available We used hierarchical tree clustering to derive a functional organizational chart of 52 human cortical areas (26 per hemisphere from zero-lag correlations calculated between single-voxel, prewhitened, resting-state BOLD fMRI time series in 18 subjects. No special resting-state networks were identified. There were four major features in the resulting tree (dendrogram. First, there was a strong clustering of homotopic, left-right hemispheric areas. Second, cortical areas were concatenated in multiple, partially overlapping clusters. Third, the arrangement of the areas revealed a layout that closely resembled the actual layout of the cerebral cortex, namely an orderly progression from anterior to posterior. And fourth, the layout of the cortical areas in the tree conformed to principles of efficient, compact layout of components proposed by Cherniak. Since the tree was derived on the basis of the strength of neural correlations, these results document an orderly relation between functional interactions and layout, i.e. between structure and function.

  14. Structural asymmetry of the human cerebral cortex: Regional and between-subject variability of surface area, cortical thickness, and local gyrification.

    Science.gov (United States)

    Chiarello, Christine; Vazquez, David; Felton, Adam; McDowell, Alessandra

    2016-12-01

    Structural asymmetry varies across individuals, brain regions, and metrics of cortical organization. The current study investigated regional differences in asymmetry of cortical surface area, thickness, and local gyrification, and the extent of between-subject variability in these metrics, in a sample of healthy young adults (N=200). Between-subject variability in cortical structure may provide a means to assess the extent of biological flexibility or constraint of brain regions, and we explored the potential influence of this variability on the phenotypic expression of structural asymmetry. The findings demonstrate that structural asymmetries are nearly ubiquitous across the cortex, with differing regional organization for the three cortical metrics. This implies that there are multiple, only partially overlapping, maps of structural asymmetry. The results further indicate that the degree of asymmetry of a brain region can be predicted by the extent of the region's between-subject variability. These findings provide evidence that reduced biological constraint promotes the expression of strong structural asymmetry.

  15. Comparative study of muscular tonus in spastic tetra paretic cerebral palsy in children with predominantly cortical and subcortical lesions in computerized tomography of the skull; Estudo comparativo do tono muscular na paralisia cerebral tetraparetica em criancas com lesoes predominantemente corticais ou subcorticais na tomografia computadorizada de cranio

    Energy Technology Data Exchange (ETDEWEB)

    Iwabe, Cristina [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Ciencias Medicas. Dept. de Neurologia; Piovesana, Ana Maria Sedrez Gonzaga [Universidade Estadual de Campinas, SP (Brazil). Ambulatorio Multidisciplinar de Paralisia Cerebral e Neurologia Infantil

    2003-09-01

    The objective was to compare distribution and intensity of muscular tonus in spastic tetra paretic cerebral palsy (CP), correlating the clinical data with lesion location in the central nervous system. Twelve children aged two to four years old with predominantly cortical lesions (six children) and subcortical lesions (six children) were included. The tonus was analyzed in the upper (UULL) and lower limbs (LLLL) based on Durigon and Piemonte protocol. The result showed that there was no significant difference regarding tonus intensity and distribution in the UULL and LLLL in both groups. Comparing the upper and lower limbs of subjects in the same group, the LLLL presented more asymmetry and higher tonus intensity than the UULL. It was concluded that in this study children with CP as a result of predominantly cortical or subcortical lesions present a similar deficit in tonus modulation, causing a symmetric and homogeneous distribution of hypertonicity, which is predominant in the LLLL. (author)

  16. Effects of ketamine,midazolam,thiopental,and propofol on brain ischemia injury in rat cerebral cortical slices%氯胺酮,咪唑安定,硫喷妥钠和异丙酚对大鼠皮层脑片缺血性损伤的作用

    Institute of Scientific and Technical Information of China (English)

    薛庆生; 于布为; 王泽剑; 陈红专

    2004-01-01

    AIM: To compare the effects of ketamine, midazolam, thiopental, and propofol on brain ischemia by the model of oxygen-glucose deprivation (OGD) in rat cerebral cortical slices. METHODS: Cerebral cortical slices were incubated in 2 % 2,3,5-triphenyltetrazolium chloride (TTC) solution after OGD, the damages and effects of ketamine,midazolam, thiopental, and propofol were quantitativlye evaluated by ELISA reader of absorbance (A) at 490 nm,which indicated the red formazan extracted from slices, lactic dehydrogenase (LDH) releases in the incubated supernate were also measured. RESULTS: Progressive prolongation of OGD resulted in decreases of TTC staining.The percentage of tissue injury had a positive correlation with LDH releases, r=0.9609, P<0.01. Two hours of reincubation aggravated the decrease of TTC staining compared with those slices stained immediately after OGD (P<0.01). These four anesthetics had no effects on the TTC staining of slices. Ketamine completely inhibited the decrease of A value induced by 10 min of OGD injury. High concentrations of midazolam (10 μmol/L) and thiopental (400 μmol/L)partly attenuated this decrease. Propofol at high concentration (100 μmol/L) enhanced the decrease of A value induced by 10 min of OGD injury (P<0.01). CONCLUSION: Ketamine, high concentration of midazolam and thiopental have neuroprotective effects against OGD injury in rat cerebral cortical slices, while high concentration of propofol augments OGD injury in rat cerebral cortical slices.

  17. The cortical motor system of the marmoset monkey (Callithrix jacchus).

    Science.gov (United States)

    Bakola, Sophia; Burman, Kathleen J; Rosa, Marcello G P

    2015-04-01

    Precise descriptions of the anatomical pathways that link different areas of the cerebral cortex are essential to the understanding of the sensorimotor and association processes that underlie human actions, and their impairment in pathological situations. Many years of research in macaque monkeys have critically shaped how we currently think about cortical motor function in humans. However, it is important to obtain additional understanding about the homologies between cortical areas in human and various non-human primates, and in particular how evolutionary changes in connectivity within specific neural circuits impact on the capacity for different behaviors. Current research has converged on the New World marmoset monkey as an important animal model for cortical function and dysfunction, emphasizing advantages unique to this species. However, the motor repertoire of the marmoset differs from that of the macaque in many ways, including the capacity for skilled use of the hands. Here, we review current knowledge about the cortical frontal areas in marmosets, which are key to the generation and control of motor behaviors, with focus on comparative analyses. We note significant parallels with the macaque monkey, as well as a few potentially important differences, which suggest future directions for work involving architectonic and functional analyses.

  18. Cerebro-cerebellar circuits in autism spectrum disorder.

    Science.gov (United States)

    D'Mello, Anila M; Stoodley, Catherine J

    2015-01-01

    The cerebellum is one of the most consistent sites of abnormality in autism spectrum disorder (ASD) and cerebellar damage is associated with an increased risk of ASD symptoms, suggesting that cerebellar dysfunction may play a crucial role in the etiology of ASD. The cerebellum forms multiple closed-loop circuits with cerebral cortical regions that underpin movement, language, and social processing. Through these circuits, cerebellar dysfunction could impact the core ASD symptoms of social and communication deficits and repetitive and stereotyped behaviors. The emerging topography of sensorimotor, cognitive, and affective subregions in the cerebellum provides a new framework for interpreting the significance of regional cerebellar findings in ASD and their relationship to broader cerebro-cerebellar circuits. Further, recent research supports the idea that the integrity of cerebro-cerebellar loops might be important for early cortical development; disruptions in specific cerebro-cerebellar loops in ASD might impede the specialization of cortical regions involved in motor control, language, and social interaction, leading to impairments in these domains. Consistent with this concept, structural, and functional differences in sensorimotor regions of the cerebellum and sensorimotor cerebro-cerebellar circuits are associated with deficits in motor control and increased repetitive and stereotyped behaviors in ASD. Further, communication and social impairments are associated with atypical activation and structure in cerebro-cerebellar loops underpinning language and social cognition. Finally, there is converging evidence from structural, functional, and connectivity neuroimaging studies that cerebellar right Crus I/II abnormalities are related to more severe ASD impairments in all domains. We propose that cerebellar abnormalities may disrupt optimization of both structure and function in specific cerebro-cerebellar circuits in ASD.

  19. Cerebro-cerebellar circuits in autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Anila M. D'Mello

    2015-11-01

    Full Text Available The cerebellum is one of the most consistent sites of abnormality in autism spectrum disorder (ASD and cerebellar damage is associated with an increased risk of ASD symptoms, suggesting that cerebellar dysfunction may play a crucial role in the etiology of ASD. The cerebellum forms multiple closed-loop circuits with cerebral cortical regions that underpin movement, language, and social processing. Through these circuits, cerebellar dysfunction could impact the core ASD symptoms of social and communication deficits and repetitive and stereotyped behaviors. The emerging topography of sensorimotor, cognitive, and affective subregions in the cerebellum provides a new framework for interpreting the significance of regional cerebellar findings in ASD and their relationship to broader cerebro-cerebellar circuits. Further, recent research supports the idea that the integrity of cerebro-cerebellar loops might be important for early cortical development; disruptions in specific cerebro-cerebellar loops in ASD might impede the specialization of cortical regions involved in motor control, language, and social interaction, leading to impairments in these domains. Consistent with this concept, structural and functional differences in sensorimotor regions of the cerebellum and sensorimotor cerebro-cerebellar circuits are associated with deficits in motor control and increased repetitive and stereotyped behaviors in ASD. In contrast, communication and social impairments are associated with atypical activation and structure in cerebro-cerebellar loops underpinning language and social cognition. Finally, there is converging evidence from structural, functional, and connectivity neuroimaging studies that cerebellar right Crus I/II abnormalities are related to more severe ASD impairments in all domains. We propose that cerebellar abnormalities may disrupt optimization of both structure and function in specific cerebro-cerebellar circuits in ASD.

  20. Lysosomal membrane permeabilization is involved in oxidative stress-induced apoptotic cell death in LAMP2-deficient iPSCs-derived cerebral cortical neurons

    Directory of Open Access Journals (Sweden)

    Cheuk-Yiu Law

    2016-03-01

    Our results from cellular fractionation and inhibitor blockade experiments further revealed that oxidative stress-induced apoptosis in the LAMP2-deficient cortical neurons was caused by increased abundance of cytosolic cathepsin L. These results suggest the involvement of lysosomal membrane permeabilization in the LAMP2 deficiency associated neural injury.

  1. /sup 3/H)pirenzepine and (-)-(/sup 3/H)quinuclidinyl benzilate binding to rat cerebral cortical and cardiac muscarinic cholinergic sites. I. Characterization and regulation of agonist binding to putative muscarinic subtypes

    Energy Technology Data Exchange (ETDEWEB)

    Watson, M.; Yamamura, H.I.; Roeske, W.R.

    1986-05-01

    The binding and regulation of selected muscarinic agonists to putative subtypes in rat cerebral cortex and heart were studied. Parallel inhibition studies of (/sup 3/H)pirenzepine ((/sup 3/H)PZ) and (-)-(/sup 3/H)quinuclidinylbenzilate ((-)-(/sup 3/H)QNB)-labeled membranes were done with and without 30 microM guanyl-5'-yl imidodiphosphate (Gpp(NH)p) at 25 degrees C in 10 mM Na-K-phosphate buffer which enhances PZ binding affinity and in modified Krebs-phosphate buffer, which mimics physiological conditions. Classical agonists such as carbachol, oxotremorine and acetylcholine inhibited (-)-(/sup 3/H)QNB binding to membranes with shallow Hill values (nH less than 1), were better fit to a 2-state model, were Gpp(NH)p-regulated and showed lower affinity in modified Krebs-phosphate buffer than in 10 mM Na-K-phosphate buffer. Some agonists were not significantly better fit to a 2-state model in (/sup 3/H)PZ-labeled cortical membranes, especially in 10 mM Na-K-phosphate buffer. Whereas putative M1 and M2 binding sites distinguished by PZ possessed multiple agonist affinity states, as judged by carbachol, and agonist binding to (/sup 3/H)PZ-labeled sites were Gpp(NH)p modulated, the partial agonist pilocarpine and nonclassical agonist McN-A-343 (3-(m-chlorophenylcarbamoyloxy)-2-butynyl trimethylammonium chloride) showed little Gpp(NH)p-induced shift in (/sup 3/H)PZ-labeled cortical membranes in physiological conditions. Agonist binding to (-)-(/sup 3/H)QNB-labeled putative M2 cardiac sites was more sensitive to Gpp(NH)p than (-)-(/sup 3/H)QNB-labeled cortical sites. Carbachol and acetylcholine showed significant selectivity for putative M2 sites.

  2. Tangential migration of glutamatergic neurons and cortical patterning during development: Lessons from Cajal-Retzius cells.

    Science.gov (United States)

    Barber, Melissa; Pierani, Alessandra

    2016-08-01

    Tangential migration is a mode of cell movement, which in the developing cerebral cortex, is defined by displacement parallel to the ventricular surface and orthogonal to the radial glial fibers. This mode of long-range migration is a strategy by which distinct neuronal classes generated from spatially and molecularly distinct origins can integrate to form appropriate neural circuits within the cortical plate. While it was previously believed that only GABAergic cortical interneurons migrate tangentially from their origins in the subpallial ganglionic eminences to integrate in the cortical plate, it is now known that transient populations of glutamatergic neurons also adopt this mode of migration. These include Cajal-Retzius cells (CRs), subplate neurons (SPs), and cortical plate transient neurons (CPTs), which have crucial roles in orchestrating the radial and tangential development of the embryonic cerebral cortex in a noncell-autonomous manner. While CRs have been extensively studied, it is only in the last decade that the molecular mechanisms governing their tangential migration have begun to be elucidated. To date, the mechanisms of SPs and CPTs tangential migration remain unknown. We therefore review the known signaling pathways, which regulate parameters of CRs migration including their motility, contact-redistribution and adhesion to the pial surface, and discuss this in the context of how CR migration may regulate their signaling activity in a spatial and temporal manner. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 847-881, 2016.

  3. Disorders of cortical formation: MR imaging features.

    Science.gov (United States)

    Abdel Razek, A A K; Kandell, A Y; Elsorogy, L G; Elmongy, A; Basett, A A

    2009-01-01

    The purpose of this article was to review the embryologic stages of the cerebral cortex, illustrate the classification of disorders of cortical formation, and finally describe the main MR imaging features of these disorders. Disorders of cortical formation are classified according to the embryologic stage of the cerebral cortex at which the abnormality occurred. MR imaging shows diminished cortical thickness and sulcation in microcephaly, enlarged dysplastic cortex in hemimegalencephaly, and ipsilateral focal cortical thickening with radial hyperintense bands in focal cortical dysplasia. MR imaging detects smooth brain in classic lissencephaly, the nodular cortex with cobblestone cortex with congenital muscular dystrophy, and the ectopic position of the gray matter with heterotopias. MR imaging can detect polymicrogyria and related syndromes as well as the types of schizencephaly. We concluded that MR imaging is essential to demonstrate the morphology, distribution, and extent of different disorders of cortical formation as well as the associated anomalies and related syndromes.

  4. A Rare Hydrocephalus Complication: Cortical Blindness.

    Science.gov (United States)

    Ünal, Emre; Göçmen, Rahşan; Işıkay, Ayşe İlksen; Tekşam, Özlem

    2015-01-01

    Cortical blindness related to bilateral occipital lobe infarction is an extremely rare complication of hydrocephalus. Compression of the posterior cerebral artery, secondary to tentorial herniation, is the cause of occipital infarction. Particularly in children and mentally ill patients, cortical blindness may be missed. Therefore, early diagnosis and treatment of hydrocephalus is important. We present herein a child of ventricular shunt malfunction complicated by cortical blindness.

  5. 小鼠大脑皮质神经元电穿孔转染条件的优化%Optimization of electroporation parameters for cerebral cortical neurons of mouse

    Institute of Scientific and Technical Information of China (English)

    詹从清; 黄静; 魏燕燕; 陈晶; 李云庆; 武胜昔

    2011-01-01

    Objective: To optimize the electroporation parameters in primary cultured cerebral cortical neurons of mouse. Methods: Green fluorescent protein (GFP) expression plasmid shNC was transferred into cortical neurons using different electroporation voltages and impulse times. Expression of GFP was observed after twenty-four hours of transfection and the electroporation efficiencies were analyzed to determine the optimal electroporation conditions. Results: The highest electroporation transfection rate was achieved under the conditions of voltage 200 v, pulse time 25 ms or voltage 250 v, pulse time 15 ms for the mouse cortical neurons. The transfection rate was (31. 15 ± 1.89)% and(29. 10 ±1.93 ) % respectively. Conclusion: Electroporation is a highly efficient gene transfection method. Optimized electroporation parameters can improve the electroporation efficiency of the mouse cortical neurons.%目的:以原代培养的小鼠大脑皮质神经元为研究工具,优化电穿孔转染条件.方法:通过设置不同的电压和脉冲时间组合等电转染条件,将表达绿色荧光蛋白(GFP)的shNC质粒导入小鼠大脑皮质神经元,24 h后观察并比较神经元的转染效率,确定最佳电转染条件.结果:200 v电压,25 ms,脉冲时间或250 v电压,15 ms脉冲时间的转染条件下,小鼠大脑皮质神经元可获得较好的转染效率,分别为(31.15±1.89)%和(29.10±1.93)%.结论:电穿孔转染是一种高效的基因转染方法,通过条件的优化,可以提高小鼠大脑皮质神经元的电转染效率.

  6. Similar patterns of cortical expansion during human development and evolution.

    Science.gov (United States)

    Hill, Jason; Inder, Terrie; Neil, Jeffrey; Dierker, Donna; Harwell, John; Van Essen, David

    2010-07-20

    The cerebral cortex of the human infant at term is complexly folded in a similar fashion to adult cortex but has only one third the total surface area. By comparing 12 healthy infants born at term with 12 healthy young adults, we demonstrate that postnatal cortical expansion is strikingly nonuniform: regions of lateral temporal, parietal, and frontal cortex expand nearly twice as much as other regions in the insular and medial occipital cortex. This differential postnatal expansion may reflect regional differences in the maturity of dendritic and synaptic architecture at birth and/or in the complexity of dendritic and synaptic architecture in adults. This expression may also be associated with differential sensitivity of cortical circuits to childhood experience and insults. By comparing human and macaque monkey cerebral cortex, we infer that the pattern of human evolutionary expansion is remarkably similar to the pattern of human postnatal expansion. To account for this correspondence, we hypothesize that it is beneficial for regions of recent evolutionary expansion to remain less mature at birth, perhaps to increase the influence of postnatal experience on the development of these regions or to focus prenatal resources on regions most important for early survival.

  7. Effect of vitamin E on cerebral cortical oxidative stress and brain-derived neurotrophic factor gene expression induced by hypoxia and exercise in rats.

    Science.gov (United States)

    Sakr, H F; Abbas, A M; El Samanoudy, A Z

    2015-04-01

    Brain-derived neurotrophic factor (BDNF) is involved in the proliferation of neurons, and its expression increases significantly with exercise. We aimed to investigate the effects of chronic exercise (swimming) and sustained hypoxia on cortical BDNF expression in both the presence and absence of vitamin E. Sixty four male Sprague-Dawley rats were divided into two equal groups; a normoxic group and a hypoxic group. Both groups were equally subdivided into four subgroups: sedentary, sedentary with vitamin E, chronic exercise either with or without vitamin E supplementation. Arterial PO(2), and the levels of cortical malondialdehyde (MDA), antioxidants (reduced glutathione GSH, superoxide dismutase (SOD), catalase (CAT) and vitamin E) and BDNF gene expression were investigated. Hypoxia significantly increased MDA production and BDNF gene expression and decreased the antioxidants compared to control rats. Chronic exercise in hypoxic and normoxic rats increased MDA level and BDNF gene expression and decreased the antioxidants. Providing vitamin E supplementation to the hypoxic and normoxic rats significantly reduced MDA and BDNF gene expression and increased antioxidants. We conclude that sustained hypoxia and chronic exercise increased BDNF gene expression and induced oxidative stress. Moreover, vitamin E attenuated the oxidative stress and decreased BDNF gene expression in sustained hypoxia and chronic exercise which confirms the oxidative stress-induced stimulation of BDNF gene expression.

  8. Human Auditory and Adjacent Nonauditory Cerebral Cortices Are Hypermetabolic in Tinnitus as Measured by Functional Near-Infrared Spectroscopy (fNIRS).

    Science.gov (United States)

    Issa, Mohamad; Bisconti, Silvia; Kovelman, Ioulia; Kileny, Paul; Basura, Gregory J

    2016-01-01

    Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex) and non-ROI (adjacent nonauditory cortices) during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS). Control and tinnitus participants with normal/near-normal hearing were tested during a passive auditory task. Hemodynamic activity was monitored over ROI and non-ROI under episodic periods of auditory stimulation with 750 or 8000 Hz tones, broadband noise, and silence. During periods of silence, tinnitus participants maintained increased hemodynamic responses in ROI, while a significant deactivation was seen in controls. Interestingly, non-ROI activity was also increased in the tinnitus group as compared to controls during silence. The present results demonstrate that both auditory and select nonauditory cortices have elevated hemodynamic activity in participants with tinnitus in the absence of an external auditory stimulus, a finding that may reflect basic science neural correlates of tinnitus that ultimately contribute to phantom sound perception.

  9. Human Auditory and Adjacent Nonauditory Cerebral Cortices Are Hypermetabolic in Tinnitus as Measured by Functional Near-Infrared Spectroscopy (fNIRS

    Directory of Open Access Journals (Sweden)

    Mohamad Issa

    2016-01-01

    Full Text Available Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex and non-ROI (adjacent nonauditory cortices during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS. Control and tinnitus participants with normal/near-normal hearing were tested during a passive auditory task. Hemodynamic activity was monitored over ROI and non-ROI under episodic periods of auditory stimulation with 750 or 8000 Hz tones, broadband noise, and silence. During periods of silence, tinnitus participants maintained increased hemodynamic responses in ROI, while a significant deactivation was seen in controls. Interestingly, non-ROI activity was also increased in the tinnitus group as compared to controls during silence. The present results demonstrate that both auditory and select nonauditory cortices have elevated hemodynamic activity in participants with tinnitus in the absence of an external auditory stimulus, a finding that may reflect basic science neural correlates of tinnitus that ultimately contribute to phantom sound perception.

  10. /sup 3/H)pirenzepine and (-)-(/sup 3/H)quinuclidinyl benzilate binding to rat cerebral cortical and cardiac muscarinic cholinergic sites. II. Characterization and regulation of antagonist binding to putative muscarinic subtypes

    Energy Technology Data Exchange (ETDEWEB)

    Watson, M.; Roeske, W.R.; Yamamura, H.I.

    1986-05-01

    Studies show (/sup 3/H)PZ identified selectively a subpopulation of muscarinic binding sites compared to classical antagonists like (-)-(/sup 3/H)QNB in many central and peripheral tissues. We characterized the binding and regulation of selected antagonists to high-affinity (/sup 3/H)PZ (putative M1) and low-affinity PZ (putative M2) sites in rat cerebral cortex (predominantly M1) and heart (predominantly M2). Saturation isotherms of (/sup 3/H)PZ and (-)-(/sup 3/H)QNB were performed under various conditions. Guanyl-5'-yl-imidodiphosphate (30 microM) showed little effect on Kd (dissociation constant) or total binding capacity (total receptor density) values. Higher ionic strength buffers yielded lower affinity values for (/sup 3/H)PZ and (-)-(/sup 3/H)QNB. Kinetic studies confirmed high affinity Kd values seen in steady-state assays. We conducted inhibition studies of selected muscarinic antagonists including the reportedly cardioselective (putative M2) drug, AF-DX 116 (11-((2-(diethylamino)methyl-1-piperidinyl)-acetyl)-5, 11-dihydro-6H-pyrido(2,3-b)(1,4)-benzodiazepine-6-one), the reportedly M1 selective compound, PZ, and the classical antagonist (-)QNB, using (/sup 3/H)PZ and (-)-(/sup 3/H)QNB-labeled cerebral cortical and cardiac homogenates. Assays were done with and without guanyl-5'-yl-imidophosphate at 25 degrees C in 10 mM Na-K-phosphate, 50 mM Na-K-phosphate and modified Krebs-phosphate buffer. Studies showed antagonists generally had higher affinity in 10 mM Na-K-phosphate buffer, were insensitive to guanyl-5'-yl imidodiphosphate and had Hill values (nH) nearly equal to one. Cardiac PZ/(/sup 3/H)QNB curves were steep.

  11. Functional magnetic resonance imaging suggests automatization of the cortical response to inspiratory threshold loading in humans.

    Science.gov (United States)

    Raux, Mathieu; Tyvaert, Louise; Ferreira, Michael; Kindler, Félix; Bardinet, Eric; Karachi, Carine; Morelot-Panzini, Capucine; Gotman, Jean; Pike, G Bruce; Koski, Lisa; Similowski, Thomas

    2013-12-01

    Inspiratory threshold loading (ITL) induces cortical activation. It is sustained over time and is resistant to distraction, suggesting automaticity. We hypothesized that ITL-induced changes in cerebral activation may differ between single-breath ITL and continuous ITL, with differences resembling those observed after cortical automatization of motor tasks. We analyzed the brain blood oxygen level dependent (BOLD) signal of 11 naive healthy volunteers during 5 min of random, single-breath ITL and 5 min of continuous ITL. Single-breath ITL increased BOLD in many areas (premotor cortices, bilateral insula, cerebellum, reticular formation of the lateral mesencephalon) and decreased BOLD in regions co-localizing with the default mode network. Continuous ITL induced signal changes in a limited number of areas (supplementary motor area). These differences are comparable to those observed before and after overlearning of motor tasks. We conclude that the respiratory-related cortical activation observed in response to ITL is likely due to automated, attention-independent mechanisms. Also, ITL activates cortical circuits right from the first breath.

  12. Functional involvement of cerebral cortex in human narcolepsy.

    Science.gov (United States)

    Oliviero, A; Della Marca, G; Tonali, P A; Pilato, F; Saturno, E; Dileone, M; Versace, V; Mennuni, G; Di Lazzaro, V

    2005-01-01

    The pathophysiology of human narcolepsy is still poorly understood. The hypoactivity of some neurotransmitter systems has been hypothesised on the basis of the canine model. To determine whether narcolepsy is associated with changes in excitability of the cerebral cortex, we assessed the excitability of the motor cortex with transcranial magnetic stimulation (TMS) in 13 patients with narcolepsy and in 12 control subjects. We used several TMS paradigms that can provide information on the excitability of the motor cortex. Resting and active motor thresholds were higher in narcoleptic patients than in controls and intracortical inhibition was more pronounced in narcoleptic patients. No changes in the other evaluated measures were detected. These results are consistent with an impaired balance between excitatory and inhibitory intracortical circuits in narcolepsy that leads to cortical hypoexcitability. We hypothesise that the deficiency of the excitatory hypocretin/orexin-neurotransmitter-system in narcolepsy is reflected in changes of cortical excitability since circuits originating in the lateral hypothalamus and in the basal forebrain project widely to the neocortex, including motor cortex. This abnormal excitability of cortical networks could be the physiological correlate of excessive daytime sleepiness and it could be the substrate for allowing dissociated states of wakefulness and sleep to emerge suddenly while patients are awake, which constitute the symptoms of narcolepsy.

  13. Evaluation of cortical plasticity in children with cerebral palsy undergoing constraint-induced movement therapy based on functional near-infrared spectroscopy

    Science.gov (United States)

    Cao, Jianwei; Khan, Bilal; Hervey, Nathan; Tian, Fenghua; Delgado, Mauricio R.; Clegg, Nancy J.; Smith, Linsley; Roberts, Heather; Tulchin-Francis, Kirsten; Shierk, Angela; Shagman, Laura; MacFarlane, Duncan; Liu, Hanli; Alexandrakis, George

    2015-04-01

    Sensorimotor cortex plasticity induced by constraint-induced movement therapy (CIMT) in six children (10.2±2.1 years old) with hemiplegic cerebral palsy was assessed by functional near-infrared spectroscopy (fNIRS). The activation laterality index and time-to-peak/duration during a finger-tapping task and the resting-state functional connectivity were quantified before, immediately after, and 6 months after CIMT. These fNIRS-based metrics were used to help explain changes in clinical scores of manual performance obtained concurrently with imaging time points. Five age-matched healthy children (9.8±1.3 years old) were also imaged to provide comparative activation metrics for normal controls. Interestingly, the activation time-to-peak/duration for all sensorimotor centers displayed significant normalization immediately after CIMT that persisted 6 months later. In contrast to this improved localized activation response, the laterality index and resting-state connectivity metrics that depended on communication between sensorimotor centers improved immediately after CIMT, but relapsed 6 months later. In addition, for the subjects measured in this work, there was either a trade-off between improving unimanual versus bimanual performance when sensorimotor activation patterns normalized after CIMT, or an improvement occurred in both unimanual and bimanual performance but at the cost of very abnormal plastic changes in sensorimotor activity.

  14. Cerebral blood flow in posterior cortical nodes of the default mode network decreases with task engagement but remains higher than in most brain regions.

    Science.gov (United States)

    Pfefferbaum, Adolf; Chanraud, Sandra; Pitel, Anne-Lise; Müller-Oehring, Eva; Shankaranarayanan, Ajit; Alsop, David C; Rohlfing, Torsten; Sullivan, Edith V

    2011-01-01

    Functional neuroimaging studies provide converging evidence for existence of intrinsic brain networks activated during resting states and deactivated with selective cognitive demands. Whether task-related deactivation of the default mode network signifies depressed activity relative to the remaining brain or simply lower activity relative to its resting state remains controversial. We employed 3D arterial spin labeling imaging to examine regional cerebral blood flow (CBF) during rest, a spatial working memory task, and a second rest. Change in regional CBF from rest to task showed significant normalized and absolute CBF reductions in posterior cingulate, posterior-inferior precuneus, and medial frontal lobes . A Statistical Parametric Mapping connectivity analysis, with an a priori seed in the posterior cingulate cortex, produced deactivation connectivity patterns consistent with the classic "default mode network" and activation connectivity anatomically consistent with engagement in visuospatial tasks. The large task-related CBF decrease in posterior-inferior precuneus relative to its anterior and middle portions adds evidence for the precuneus' heterogeneity. The posterior cingulate and posterior-inferior precuneus were also regions of the highest CBF at rest and during task performance. The difference in regional CBF between intrinsic (resting) and evoked (task) activity levels may represent functional readiness or reserve vulnerable to diminution by conditions affecting perfusion.

  15. Neuronal activity (c-Fos delineating interactions of the cerebral cortex and basal ganglia

    Directory of Open Access Journals (Sweden)

    Mei-Hong eQiu

    2014-03-01

    Full Text Available The cerebral cortex and basal ganglia (BG form a neural circuit that is disrupted in disorders such as Parkinson’s disease. We found that neuronal activity (c-Fos in the BG followed cortical activity, i.e., high in arousal state and low in sleep state. To determine if cortical activity is necessary for BG activity, we administered atropine to rats to induce a dissociative state resulting in slow-wave EEG but hyperactive motor behaviors. Atropine blocked c-Fos expression in the cortex and BG, despite high c-Fos expression in the sub-cortical arousal neuronal groups and thalamus, indicating that cortical activity is required for BG activation. To identify which glutamate receptors in the BG that mediate cortical inputs, we injected ketamine (NMDA receptor antagonist and 6-cyano-nitroquinoxaline-2, 3-dione (CNQX, a non-NMDA receptor antagonist. Systemic ketamine and CNQX administration revealed that NMDA receptors mediated subthalamic nucleus (STN input to internal globus pallidus (GPi and substantia nigra pars reticulata (SNr, while non-NMDA receptor mediated cortical input to the STN. Both types of glutamate receptors were involved in mediating cortical input to the striatum. Dorsal striatal (caudoputamen, CPu dopamine depletion by 6-hydroxydopamine resulted in reduced activity of the CPu, globus pallidus externa (GPe, and STN but increased activity of the GPi, SNr and putative layer V neurons in the motor cortex. Our results reveal that the cortical activity is necessary for BG activity and clarifies the pathways and properties of the BG-cortical network and their putative role in the pathophysiology of BG disorders.

  16. Endogenous polyamines regulate cortical neuronal excitability by blocking voltage-gated Na+ channels.

    Science.gov (United States)

    Fleidervish, Ilya A; Libman, Lior; Katz, Efrat; Gutnick, Michael J

    2008-12-02

    Because the excitable properties of neurons in the neocortex depend on the characteristics of voltage-gated Na(+) channels, factors which regulate those characteristics can fundamentally modify the dynamics of cortical circuits. Here, we report on a novel neuromodulatory mechanism that links the availability of Na(+) channels to metabolism of polyamines (PAs) in the cerebral cortex. Using single channel and whole-cell recordings, we found that products of PA metabolism, the ubiquitous aliphatic polycations spermine and spermidine, are endogenous blockers of Na(+) channels in layer 5 pyramidal cells. Because the blockade is activity-dependent, it is particularly effective against Na(+) channels which fail to inactivate rapidly and thus underlie the persistent Na(+) current. At the level of the local cortical circuit, pharmacological depletion of PAs led to increased spontaneous spiking and periods of hypersynchronous discharge. Our data suggest that changes in PA levels, whether associated with normal brain states or pathological conditions, profoundly modify Na(+) channel availability and thereby shape the integrative behavior of single neurons and neocortical circuits.

  17. Synchronous changes of cortical thickness and corresponding white matter microstructure during brain development accessed by diffusion MRI tractography from parcellated cortex

    Directory of Open Access Journals (Sweden)

    Tina eJeon

    2015-12-01

    Full Text Available Cortical thickness (CT changes during normal brain development is associated with complicated cellular and molecular processes including synaptic pruning and apoptosis. In parallel, the microstructural enhancement of developmental white matter (WM axons with their neuronal bodies in the cerebral cortex has been widely reported with measurements of metrics derived from diffusion tensor imaging (DTI, especially fractional anisotropy (FA. We hypothesized that the changes of CT and microstructural enhancement of corresponding axons are highly interacted during development. DTI and T1-weighted images of 50 healthy children and adolescents between the ages of 7 to 25 years were acquired. With the parcellated cortical gyri transformed from T1-weighted images to DTI space as the tractography seeds, probabilistic tracking was performed to delineate the WM fibers traced from specific parcellated cortical regions. CT was measured at certain cortical regions and FA was measured from the WM fibers traced from same cortical regions. The CT of all frontal cortical gyri, includeing Brodmann areas 4, 6, 8, 9, 10, 11, 44, 45, 46 and 47, decreased significantly and heterogeneously; concurrently, significant and heterogeneous increases of FA of WM traced from corresponding regions were found. We further revealed significant correlation between the slopes of the CT decrease and the slopes of corresponding WM FA increase in all frontal cortical gyri, suggesting coherent cortical pruning and corresponding WM microstructural enhancement. Such correlation was not found in cortical regions other than frontal cortex. The molecular and cellular mechanisms of these synchronous changes may be associated with overlapping signaling pathways of axonal guidance, synaptic pruning, neuronal apoptosis and more prevalent interstitial neurons in the prefrontal cortex. Revealing the coherence of cortical and WM structural changes during development may open a new window for

  18. EFFECTS OF EXPOSURE TO LOW-INTENSITY ELECTROMAGNETIC FIELDS ON CEREBRAL CORTICAL NEURONS IN MICE%低强度电磁辐射对小鼠脑皮质神经元的损伤效应

    Institute of Scientific and Technical Information of China (English)

    李贤慧; 张新昌; 王刚; 陈小义

    2011-01-01

    Objective To investigate the effects of exposure to low-intensity electromagnetic fields on cerebral cortical neurons in mice, so as to provide the basis for working out protective measures against electromagnetic radiation damage. Methods Primary neonatal mouse neurons were exposed to 900 MHz electromagnetic fields with power density of 8 mW/cm2 for 1 h, 6 h, and 12 h respectively. Analysis of cell viability was performed by CCK-8 kit, and apoptosis was detected by Annexin V-fluorescein isothiocyanate (FTTC)/propidium (PI) kit and flow cytometry after exposure. Results The cell viability of neurons exposed to power density of 8 mW/cm2 for 1 h was generally not affected, and the measurement of apoptosis showed no differences between exposed neurons and unexposed control neurons too. However, significant changes were observed in the neurons exposed to electromagnetic fields for 6 h or 12 h. The cell viability in neurons exposed for 6 h or 12 h decreased 22% and 37% more respectively than in the unexposed control neurons. The cell apoptosis rate was 5.6% in control, but in exposed ones for 6 h, or 12 h increased to 17.6% or 30.8% respectively(P <0.05). Conclusion Exposure to low-intensity electromagnetic fields for more than 6 h might cause primary cerebral cortical neurons damage and apoptosis.%目的 研究低强度电磁辐射对原代培养的小鼠脑皮质神经元的损伤效应,为制定防护电磁辐射对中枢神经系统危害的措施提供依据.方法 将原代培养的小鼠脑皮质神经元给予900 MHz平均功率密度为8 mW/cm2的电磁波持续辐射1 h、6 h、12 h,辐射后分别用CCK-8试剂盒检测细胞活力,用Annexin V-F1TC/PI双标记试剂盒流式细胞仪检测细胞凋亡率.结果 细胞活力分析显示,与对照组细胞比较,持续辐射1 h组差异不显著;辐射6 h组细胞活力则降低22%(P<0.05),辐射12 h组细胞活力则降低37%(P<0.05);Annexin V-FITC/PI细胞凋亡分析显示

  19. [Posterior cortical atrophy].

    Science.gov (United States)

    Solyga, Volker Moræus; Western, Elin; Solheim, Hanne; Hassel, Bjørnar; Kerty, Emilia

    2015-06-02

    Posterior cortical atrophy is a neurodegenerative condition with atrophy of posterior parts of the cerebral cortex, including the visual cortex and parts of the parietal and temporal cortices. It presents early, in the 50s or 60s, with nonspecific visual disturbances that are often misinterpreted as ophthalmological, which can delay the diagnosis. The purpose of this article is to present current knowledge about symptoms, diagnostics and treatment of this condition. The review is based on a selection of relevant articles in PubMed and on the authors' own experience with the patient group. Posterior cortical atrophy causes gradually increasing impairment in reading, distance judgement, and the ability to perceive complex images. Examination of higher visual functions, neuropsychological testing, and neuroimaging contribute to diagnosis. In the early stages, patients do not have problems with memory or insight, but cognitive impairment and dementia can develop. It is unclear whether the condition is a variant of Alzheimer's disease, or whether it is a separate disease entity. There is no established treatment, but practical measures such as the aid of social care workers, telephones with large keypads, computers with voice recognition software and audiobooks can be useful. Currently available treatment has very limited effect on the disease itself. Nevertheless it is important to identify and diagnose the condition in its early stages in order to be able to offer patients practical assistance in their daily lives.

  20. Relaxed genetic control of cortical organization in human brains compared with chimpanzees.

    Science.gov (United States)

    Gómez-Robles, Aida; Hopkins, William D; Schapiro, Steven J; Sherwood, Chet C

    2015-12-01

    The study of hominin brain evolution has focused largely on the neocortical expansion and reorganization undergone by humans as inferred from the endocranial fossil record. Comparisons of modern human brains with those of chimpanzees provide an additional line of evidence to define key neural traits that have emerged in human evolution and that underlie our unique behavioral specializations. In an attempt to identify fundamental developmental differences, we have estimated the genetic bases of brain size and cortical organization in chimpanzees and humans by studying phenotypic similarities between individuals with known kinship relationships. We show that, although heritability for brain size and cortical organization is high in chimpanzees, cerebral cortical anatomy is substantially less genetically heritable than brain size in humans, indicating greater plasticity and increased environmental influence on neurodevelopment in our species. This relaxed genetic control on cortical organization is especially marked in association areas and likely is related to underlying microstructural changes in neural circuitry. A major result of increased plasticity is that the development of neural circuits that underlie behavior is shaped by the environmental, social, and cultural context more intensively in humans than in other primate species, thus providing an anatomical basis for behavioral and cognitive evolution.

  1. Basal forebrain motivational salience signal enhances cortical processing and decision speed

    Directory of Open Access Journals (Sweden)

    Sylvina M Raver

    2015-10-01

    Full Text Available The basal forebrain (BF contains major projections to the cerebral cortex, and plays a well-documented role in arousal, attention, decision-making, and in modulating cortical activity. BF neuronal degeneration is an early event in Alzheimer’s disease and dementias, and occurs in normal cognitive aging. While the BF is best known for its population of cortically projecting cholinergic neurons, the region is anatomically and neurochemically diverse, and also contains prominent populations of non-cholinergic projection neurons. In recent years, increasing attention has been dedicated to these non-cholinergic BF neurons in order to better understand how non-cholinergic BF circuits control cortical processing and behavioral performance. In this review, we focus on a unique population of putative non-cholinergic BF neurons that encodes the motivational salience of stimuli with a robust ensemble bursting response. We review recent studies that describe the specific physiological and functional characteristics of these BF salience-encoding neurons in behaving animals. These studies support the unifying hypothesis whereby BF salience-encoding neurons act as a gain modulation mechanism of the decision-making process to enhance cortical processing of behaviorally relevant stimuli, and thereby facilitate faster and more precise behavioral responses. This function of BF salience-encoding neurons represents a critical component in determining which incoming stimuli warrant an animal’s attention, and is therefore a fundamental and early requirement of behavioral flexibility.

  2. Grid cells and cortical representation.

    Science.gov (United States)

    Moser, Edvard I; Roudi, Yasser; Witter, Menno P; Kentros, Clifford; Bonhoeffer, Tobias; Moser, May-Britt

    2014-07-01

    One of the grand challenges in neuroscience is to comprehend neural computation in the association cortices, the parts of the cortex that have shown the largest expansion and differentiation during mammalian evolution and that are thought to contribute profoundly to the emergence of advanced cognition in humans. In this Review, we use grid cells in the medial entorhinal cortex as a gateway to understand network computation at a stage of cortical processing in which firing patterns are shaped not primarily by incoming sensory signals but to a large extent by the intrinsic properties of the local circuit.

  3. Algebraic circuits

    CERN Document Server

    Lloris Ruiz, Antonio; Parrilla Roure, Luis; García Ríos, Antonio

    2014-01-01

    This book presents a complete and accurate study of algebraic circuits, digital circuits whose performance can be associated with any algebraic structure. The authors distinguish between basic algebraic circuits, such as Linear Feedback Shift Registers (LFSRs) and cellular automata, and algebraic circuits, such as finite fields or Galois fields. The book includes a comprehensive review of representation systems, of arithmetic circuits implementing basic and more complex operations, and of the residue number systems (RNS). It presents a study of basic algebraic circuits such as LFSRs and cellular automata as well as a study of circuits related to Galois fields, including two real cryptographic applications of Galois fields.

  4. Reversible cortical blindness: posterior reversible encephalopathy syndrome.

    Science.gov (United States)

    Bandyopadhyay, Sabyasachi; Mondal, Kanchan Kumar; Das, Somnath; Gupta, Anindya; Biswas, Jaya; Bhattacharyya, Subir Kumar; Biswas, Gautam

    2010-11-01

    Cortical blindness is defined as visual failure with preserved pupillary reflexes in structurally intact eyes due to bilateral lesions affecting occipital cortex. Bilateral oedema and infarction of the posterior and middle cerebral arterial territory, trauma, glioma and meningioma of the occipital cortex are the main causes of cortical blindness. Posterior reversible encephalopathy syndrome (PRES) refers to the reversible subtype of cortical blindness and is usually associated with hypertension, diabetes, immunosuppression, puerperium with or without eclampsia. Here, 3 cases of PRES with complete or partial visual recovery following treatment in 6-month follow-up are reported.

  5. Altered low frequency oscillations of cortical vessels in patients with cerebrovascular occlusive disease – a NIRS study

    DEFF Research Database (Denmark)

    Phillip, Dorte; Iversen, Helle K; Schytz, Henrik W

    2013-01-01

    Analysis of cerebral autoregulation by measuring spontaneous oscillations in the low frequency spectrum of cerebral cortical vessels might be a useful tool for assessing risk and investigating different treatment strategies in carotid artery disease and stroke. Near infrared spectroscopy (NIRS...

  6. Modelling Human Cortical Network in Real Brain Space

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qing-Bai; FENG Hong-Bo; TANG Yi-Yuan

    2007-01-01

    Highly specific structural organization is of great significance in the topology of cortical networks.We introduce a human cortical network model.taking the specific cortical structure into account,in which nodes are brain sites placed in the actual positions of cerebral cortex and the establishment of edges depends on the spatial path length rather than the linear distance.The resulting network exhibits the essential features of cortical connectivity,properties of small-world networks and multiple clusters structure.Additionally.assortative mixing is also found in this roodel.All of these findings may be attributed to the spedtic cortical architecture.

  7. Hiperactivacion cortical y deterioro cognitivo en esquizofrenia

    OpenAIRE

    Suazo Bonnelly, Vanessa Johanna

    2014-01-01

    [ES] En este trabajo se estudió la actividad cerebral desorganizada y el deterioro cognitivo adjudicado a pacientes con esquizofrenia. Para estudiar la actividad cerebral se empleó una medida electroencefalográfica de ruido cortical (actividad promediada de fondo no ligada a la tarea) durante el desarrollo de una tarea sencilla (P300) en dos de las bandas oscilatorias (gamma y theta) más asociadas a la organización de la actividad cerebral según la literatura. Se utilizó una medida estructura...

  8. Imprinting and recalling cortical ensembles.

    Science.gov (United States)

    Carrillo-Reid, Luis; Yang, Weijian; Bando, Yuki; Peterka, Darcy S; Yuste, Rafael

    2016-08-12

    Neuronal ensembles are coactive groups of neurons that may represent building blocks of cortical circuits. These ensembles could be formed by Hebbian plasticity, whereby synapses between coactive neurons are strengthened. Here we report that repetitive activation with two-photon optogenetics of neuronal populations from ensembles in the visual cortex of awake mice builds neuronal ensembles that recur spontaneously after being imprinted and do not disrupt preexisting ones. Moreover, imprinted ensembles can be recalled by single- cell stimulation and remain coactive on consecutive days. Our results demonstrate the persistent reconfiguration of cortical circuits by two-photon optogenetics into neuronal ensembles that can perform pattern completion. Copyright © 2016, American Association for the Advancement of Science.

  9. "The developmental and functional logic of neuronal circuits": commentary on the Kavli Prize in Neuroscience.

    Science.gov (United States)

    Glover, J C

    2009-11-10

    The first Kavli Prize in Neuroscience recognizes a confluence of career achievements that together provide a fundamental understanding of how brain and spinal cord circuits are assembled during development and function in the adult. The members of the Kavli Neuroscience Prize Committee have decided to reward three scientists (Sten Grillner, Thomas Jessell, and Pasko Rakic) jointly "for discoveries on the developmental and functional logic of neuronal circuits". Pasko Rakic performed groundbreaking studies of the developing cerebral cortex, including the discovery of how radial glia guide the neuronal migration that establishes cortical layers and for the radial unit hypothesis and its implications for cortical connectivity and evolution. Thomas Jessell discovered molecular principles governing the specification and patterning of different neuron types and the development of their synaptic interconnection into sensorimotor circuits. Sten Grillner elucidated principles of network organization in the vertebrate locomotor central pattern generator, along with its command systems and sensory and higher order control. The discoveries of Rakic, Jessell and Grillner provide a framework for how neurons obtain their identities and ultimate locations, establish appropriate connections with each other, and how the resultant neuronal networks operate. Their work has significantly advanced our understanding of brain development and function and created new opportunities for the treatment of neurological disorders. Each has pioneered an important area of neuroscience research and left a legacy of exceptional scientific achievement, insight, communication, mentoring and leadership.

  10. Trigeminal nociception-induced, cerebral Fos expression in the conscious rat

    NARCIS (Netherlands)

    Ter Horst, GJ; Meijler, WJ; Korf, J; Kemper, RHA

    2001-01-01

    Little is known about trigeminal nociception-induced cerebral activity and involvement of cerebral structures in pathogenesis of trigeminovascular headaches such as migraine. Neuroimaging has demonstrated cortical, hypothalamic and brainstem activation during the attack and after abolition with suma

  11. Consistent Reconstruction of Cortical Surfaces from Longitudinal Brain MR Images

    OpenAIRE

    Li, Gang; Nie, Jingxin; Shen, Dinggang

    2011-01-01

    Accurate and consistent reconstruction of cortical surfaces from longitudinal human brain MR images is of great importance in studying subtle morphological changes of the cerebral cortex. This paper presents a new deformable surface method for consistent and accurate reconstruction of inner, central and outer cortical surfaces from longitudinal MR images. Specifically, the cortical surfaces of the group-mean image of all aligned longitudinal images of the same subject are first reconstructed ...

  12. Consistent Reconstruction of Cortical Surfaces from Longitudinal Brain MR Images

    OpenAIRE

    Li, Gang; Nie, Jingxin; Wu, Guorong; Wang, Yaping; Shen, Dinggang

    2011-01-01

    Accurate and consistent reconstruction of cortical surfaces from longitudinal human brain MR images is of great importance in studying longitudinal subtle change of the cerebral cortex. This paper presents a novel deformable surface method for consistent and accurate reconstruction of inner, central and outer cortical surfaces from longitudinal brain MR images. Specifically, the cortical surfaces of the group-mean image of all aligned longitudinal images of the same subject are first reconstr...

  13. Mean field methods for cortical network dynamics

    DEFF Research Database (Denmark)

    Hertz, J.; Lerchner, Alexander; Ahmadi, M.

    2004-01-01

    We review the use of mean field theory for describing the dynamics of dense, randomly connected cortical circuits. For a simple network of excitatory and inhibitory leaky integrate- and-fire neurons, we can show how the firing irregularity, as measured by the Fano factor, increases with the stren...... cortex. Finally, an extension of the model to describe an orientation hypercolumn provides understanding of how cortical interactions sharpen orientation tuning, in a way that is consistent with observed firing statistics...

  14. Pathogenesis of cerebral amyloid angiopathy.

    NARCIS (Netherlands)

    Rensink, A.A.M.; Waal, R.M.W. de; Kremer, H.P.H.; Verbeek, M.M.

    2003-01-01

    Cerebral amyloid angiopathy (CAA) is the result of the deposition of an amyloidogenic protein in cortical and leptomeningeal vessels. The most common type of CAA is caused by amyloid beta-protein (Abeta), which is particularly associated with Alzheimer's disease (AD). Excessive Abeta-CAA formation c

  15. Widespread cortical morphologic changes in juvenile myoclonic epilepsy: evidence from structural MRI.

    LENUS (Irish Health Repository)

    Ronan, Lisa

    2012-04-01

    Atypical morphology of the surface of the cerebral cortex may be related to abnormal cortical folding (gyrification) and therefore may indicate underlying malformations of cortical development (MCDs). Using magnetic resonance imaging (MRI)-based analysis, we examined cortical morphology in patients with juvenile myoclonic epilepsy (JME).

  16. Enhanced metabolic capacity of the frontal cerebral cortex after Pavlovian conditioning.

    Science.gov (United States)

    Bruchey, A K; Gonzalez-Lima, F

    2008-03-18

    While Pavlovian conditioning alters stimulus-evoked metabolic activity in the cerebral cortex, less is known about the effects of Pavlovian conditioning on neuronal metabolic capacity. Pavlovian conditioning may increase prefrontal cortical metabolic capacity, as suggested by evidence of changes in cortical synaptic strengths, and evidence for a shift in memory initially processed in subcortical regions to more distributed prefrontal cortical circuits. Quantitative cytochrome oxidase histochemistry was used to measure cumulative changes in brain metabolic capacity associated with both cued and contextual Pavlovian conditioning in rats. The cued conditioned group received tone-foot-shock pairings to elicit a conditioned freezing response to the tone conditioned stimulus, while the contextually conditioned group received pseudorandom tone-foot-shock pairings in an excitatory context. Untrained control group was handled daily, but did not receive any tone presentations or foot shocks. The cued conditioned group had higher cytochrome oxidase activity in the infralimbic and anterior cingulate cortex, and lower cytochrome oxidase activity in dorsal hippocampus than the other two groups. A significant increase in cytochrome oxidase activity was found in anterior cortical areas (medial, dorsal and lateral frontal cortex; agranular insular cortex; lateral and medial orbital cortex and prelimbic cortex) in both conditioned groups, as compared with the untrained control group. In addition, no differences in cytochrome oxidase activity in the somatosensory regions and the amygdala were detected among all groups. The findings indicate that cued and contextual Pavlovian conditioning induces sustained increases in frontal cortical neuronal metabolic demand resulting in regional enhancement in the metabolic capacity of anterior cortical regions. Enhanced metabolic capacity of these anterior cortical areas after Pavlovian conditioning suggests that the frontal cortex may play a

  17. Similar Motor Cortical Control Mechanisms for Precise Limb Control during Reaching and Locomotion.

    Science.gov (United States)

    Yakovenko, Sergiy; Drew, Trevor

    2015-10-28

    Throughout the course of evolution there has been a parallel development of the complexity and flexibility of the nervous system and the skeletomuscular system that it controls. This development is particularly evident for the cerebral cortical areas and the transformation of the use of the upper limbs from a purely locomotor function to one including, or restricted to, reaching and grasping. This study addresses the issue of whether the control of reaching has involved the development of new cortical circuits or whether the same neurons are used to control both locomotion and reaching. We recorded the activity of pyramidal tract neurons in the motor cortex of the cat both during voluntary gait modifications and during reaching. All cells showed generally similar patterns of activity in both tasks. More specifically, we showed that, in many cases, cells maintained a constant temporal relationship to the activity of synergistic muscle groups in each task. In addition, in some cells the relationship between the intensity of the cell discharge activity and the magnitude of the EMG activity was equally constant during gait modifications and reaching. As such, the results are compatible with the hypothesis that the corticospinal circuits used to control reaching evolved from those used to precisely modify gait. Copyright © 2015 the authors 0270-6474/15/3514476-15$15.00/0.

  18. Distinct recurrent versus afferent dynamics in cortical visual processing.

    Science.gov (United States)

    Reinhold, Kimberly; Lien, Anthony D; Scanziani, Massimo

    2015-12-01

    How intracortical recurrent circuits in mammalian sensory cortex influence dynamics of sensory representation is not understood. Previous methods could not distinguish the relative contributions of recurrent circuits and thalamic afferents to cortical dynamics. We accomplish this by optogenetically manipulating thalamus and cortex. Over the initial 40 ms of visual stimulation, excitation from recurrent circuits in visual cortex progressively increased to exceed direct thalamocortical excitation. Even when recurrent excitation exceeded thalamic excitation, upon silencing thalamus, sensory-evoked activity in cortex decayed rapidly, with a time constant of 10 ms, which is similar to a neuron's integration time window. In awake mice, this cortical decay function predicted the time-locking of cortical activity to thalamic input at frequencies thalamocortical synapses disrupted the fidelity of sensory transmission. Thus, we determine dynamics intrinsic to cortical recurrent circuits that transform afferent input in time.

  19. Malaria cerebral Cerebral malaria

    OpenAIRE

    Carlos Hugo Zapata Zapata; Silvia Blair Trujillo

    2003-01-01

    La malaria Cerebral (MC) es la complicación más frecuente de la malaria por P. falciparum; aproximadamente el 90% de las personas que la han padecido se recuperan completamente sin secuelas neurológicas. Aún no se conoce con claridad su patogénesis pero se han postulado cuatro hipótesis o mecanismos posibles: 1) citoadherencia y secuestro de glóbulos rojos parasitados en la microvasculatura cerebral; 2) formación de rosetas y aglutinación de glóbulos rojos parasitados; 3) producción de citoqu...

  20. Towards a 'canonical' agranular cortical microcircuit

    Directory of Open Access Journals (Sweden)

    Sarah F. Beul

    2015-01-01

    Full Text Available Based on regularities in the intrinsic microcircuitry of cortical areas, variants of a 'canonical' cortical microcircuit have been proposed and widely adopted, particularly in computational neuroscience and neuroinformatics. However, this circuit is founded on striate cortex, which manifests perhaps the most extreme instance of cortical organization, in terms of a very high density of cells in highly differentiated cortical layers. Most other cortical regions have a less well differentiated architecture, stretching in gradients from the very dense eulaminate primary cortical areas to the other extreme of dysgranular and agranular areas of low density and poor laminar differentiation. It is unlikely for the patterns of inter- and intra-laminar connections to be uniform in spite of strong variations of their structural substrate. This assumption is corroborated by reports of divergence in intrinsic circuitry across the cortex. Consequently, it remains an important goal to define local microcircuits for a variety of cortical types, in particular, agranular cortical regions. As a counterpoint to the striate microcircuit, which may be anchored in an exceptional cytoarchitecture, we here outline a tentative microcircuit for agranular cortex. The circuit is based on a synthesis of the available literature on the local microcircuitry in agranular cortical areas of the rodent brain, investigated by anatomical and electrophysiological approaches. A central observation of these investigations is a weakening of interlaminar inhibition as cortical cytoarchitecture becomes less distinctive. Thus, our study of agranular microcircuitry revealed deviations from the well-known 'canonical' microcircuit established for striate cortex, suggesting variations in the intrinsic circuitry across the cortex that may be functionally relevant.

  1. CREB-Dependent Regulation of GAD65 Transcription by BDNF/TrkB in Cortical Interneurons.

    Science.gov (United States)

    Sánchez-Huertas, Carlos; Rico, Beatriz

    2011-04-01

    In the cerebral cortex, the functional output of projection neurons is fine-tuned by inhibitory neurons present in the network, which use γ-aminobutyric acid (GABA) as their main neurotransmitter. Previous studies have suggested that the expression levels of the rate-limiting GABA synthetic enzyme, GAD65, depend on brain derived neurotrophic factor (BDNF)/TrkB activation. However, the molecular mechanisms by which this neurotrophic factor and its receptor controls GABA synthesis are still unknown. Here, we show a direct regulation of the GAD65 gene by BDNF-TrkB signaling via CREB in cortical interneurons. Conditional ablation of TrkB in cortical interneurons causes a cell-autonomous decrease in the synaptically enriched GAD65 protein and its transcripts levels, suggesting that transcriptional regulation of the GAD65 gene is altered. Dissection of the intracellular pathway that underlies this process revealed that BDNF/TrkB signaling controls the transcription of GAD65 in a Ras-ERK-CREB-dependent manner. Our study reveals a novel molecular mechanism through which BDNF/TrkB signaling may modulate the maturation and function of cortical inhibitory circuits.

  2. Cerebral cortex modulation of pain

    Institute of Scientific and Technical Information of China (English)

    Yu-feng XIE; Fu-quan HUO; Jing-shi TANG

    2009-01-01

    Pain is a complex experience encompassing sensory-discriminative, affective-motivational and cognitiv e-emotional com-ponents mediated by different mechanisms. Contrary to the traditional view that the cerebral cortex is not involved in pain perception, an extensive cortical network associated with pain processing has been revealed using multiple methods over the past decades. This network consistently includes, at least, the anterior cingulate cortex, the agranular insular cortex, the primary (SⅠ) and secondary somatosensory (SⅡ) cortices, the ventrolateral orbital cortex and the motor cortex. These corti-cal structures constitute the medial and lateral pain systems, the nucleus submedius-ventrolateral orbital cortex-periaque-ductal gray system and motor cortex system, respectively. Multiple neurotransmitters, including opioid, glutamate, GABA and dopamine, are involved in the modulation of pain by these cortical structures. In addition, glial cells may also be in-volved in cortical modulation of pain and serve as one target for pain management research. This review discusses recent studies of pain modulation by these cerebral cortical structures in animals and human.

  3. 鼠神经生长因子球后注射治疗脑瘫皮质盲的临床观察%Clinical Observation on the Effect of Retrobulbar Injection of Mouse Nerve Growth Factor on Cortical Blindness in Children with Cerebral Palsy

    Institute of Scientific and Technical Information of China (English)

    翟红印; 谢晓明; 孙莉

    2014-01-01

    Objective To observe the effect of retrobulbar injection of mouse nerve growth factor(mNGF) on cortical blindness in children with cerebral palsy, we aim to find the treatments for children with cortical blindness. Methods Using mNGF configuration solution by bilateral retrobulbar injection, and press the acupuncture point for 3 mins. The whole treatment consists of three courses, ten times per course and three times a week. After that the curative effect are evaluated. Rerult After observing 20 patients, 13 recovered, 2 effective, and 5 invalid. More over, 11 cases showed effective results during the first course. Conclusion Retrobulbar injection of mNGF is truly effective to cure cortical blindness.%目的:观察鼠神经生长因子球后注射治疗小儿脑瘫(cerebral palsy,CP)皮质盲的效果,寻找治疗小儿皮质盲的治疗方法。方法采用鼠神经生长因子配置液,穴位为双侧球后,注射后按压3 min止血,每周治疗3次,10次为1个疗程,治疗3个疗程评估。结果观察20例,痊愈13例,有效2例,其中无效5例,其中11例第1个疗程见效。结论通过鼠神经生长因子球后注射治疗皮质盲有确切疗效。

  4. The effect of the large cerebral cortical tubers on seizure outcomes in tuber sclerosis com-plex patients%颅内皮层大结节对结节性硬化症患者癫癎预后的影响

    Institute of Scientific and Technical Information of China (English)

    李花; 潘速跃; 胡湘蜀; 费凌霞; 郭强; 张玮; 张佩琪; 钟水生; 沈鼎烈; 周锦华

    2015-01-01

    目的:明确颅内皮层大结节对结节性硬化症(T SC )患者癫�发作及其预后的影响。方法:通过对颅内皮层结节的测量寻找颅内皮层大结节,定义为在皮层结节长宽高3个平面中,至少有2个平面的直径≥3 cm。观察颅内皮层大结节对T SC患者癫�发作及其预后的影响。结果:本研究共入组89例伴有癫�发作的T SC患者,其中男性53例,女性36例,癫�发病年龄最小为出生后1个月,最大为28岁。通过测量皮层结节发现36例(40%)患者符合本研究定义的皮层大结节。经统计学分析发现皮层大结节与痉挛发作史( P=0.022)、多种发作类型( P=0.014)、智力低下( P=0.024)及难治性癫�( P=0.041)等方面差异有统计学意义。结论:颅内皮层大结节的患者容易出现痉挛发作及多种发作类型,患者更易出现智力低下和难治性癫�,因此对于存在皮层大结节的患者需考虑早期手术治疗。%Objective:To study the effect of the large cerebral cortical tubers on seizure outcomes in patients with tuber sclerosis complex(TSC) .Methods:The diameters of at least two planes of the tuber dimention on MR were found to be ≥3 cm through the measurement of the large cerebral cortical tubers in patients with TSC .The study was aimed at observing the effect of the large cerebral cortical tubers on seizure outcomes .Results:89 patients with definite epileptic TSC were inrolved in the study ,53 male and 36 female .The onset age of seizure ranged from 1 month to 28 years .36 patients (40% ) had large cere‐bral cortical tubers according to the examination .There were statistically significant relation between the large cortical tubers and a history of infantile spasms(P=0 .022) ,multiple seizure types(P=0 .014) ,cog‐nitive impairment (P=0 .024) and refractory epilepsy(P= 0 .041) .Conclusion:The patients with large cortical tubers are found to

  5. Ataque cerebral

    OpenAIRE

    Takeuchi Tan, Yuri; Fundación Valle de Lili

    1998-01-01

    ¿Qué es un ataque cerebral?/¿Qué tipos de ataque cerebral existen?/¿Cuáles son los síntomas de un ataque cerebral?/Factores de riesgo para un ataque cerebral/Tratamiento médico del ataque cerebral/¿por qué es importante acudir temprano cuando se presentan las señales de alarma?/ Manejo preventivo del ataque cerebral isquémico/Tratamiento quirúrgico del ataque cerebral/Enfermedad vascular cerebral hemorrágica/¿Cómo está constituido el grupo de ataque cerebral de la fundación Clínica Valle d...

  6. Ataque cerebral

    OpenAIRE

    Takeuchi Tan, Yuri; Fundación Valle de Lili

    1998-01-01

    ¿Qué es un ataque cerebral?/¿Qué tipos de ataque cerebral existen?/¿Cuáles son los síntomas de un ataque cerebral?/Factores de riesgo para un ataque cerebral/Tratamiento médico del ataque cerebral/¿por qué es importante acudir temprano cuando se presentan las señales de alarma?/ Manejo preventivo del ataque cerebral isquémico/Tratamiento quirúrgico del ataque cerebral/Enfermedad vascular cerebral hemorrágica/¿Cómo está constituido el grupo de ataque cerebral de la fundación Clínica Valle d...

  7. Human-Specific Cortical Synaptic Connections and Their Plasticity: Is That What Makes Us Human?

    Science.gov (United States)

    Lourenço, Joana; Bacci, Alberto

    2017-01-01

    One outstanding difference between Homo sapiens and other mammals is the ability to perform highly complex cognitive tasks and behaviors, such as language, abstract thinking, and cultural diversity. How is this accomplished? According to one prominent theory, cognitive complexity is proportional to the repetition of specific computational modules over a large surface expansion of the cerebral cortex (neocortex). However, the human neocortex was shown to also possess unique features at the cellular and synaptic levels, raising the possibility that expanding the computational module is not the only mechanism underlying complex thinking. In a study published in PLOS Biology, Szegedi and colleagues analyzed a specific cortical circuit from live postoperative human tissue, showing that human-specific, very powerful excitatory connections between principal pyramidal neurons and inhibitory neurons are highly plastic. This suggests that exclusive plasticity of specific microcircuits might be considered among the mechanisms endowing the human neocortex with the ability to perform highly complex cognitive tasks. PMID:28103228

  8. Malformations of cortical development: genetic mechanisms and diagnostic approach

    Science.gov (United States)

    2017-01-01

    Malformations of cortical development are rare congenital anomalies of the cerebral cortex, wherein patients present with intractable epilepsy and various degrees of developmental delay. Cases show a spectrum of anomalous cortical formations with diverse anatomic and morphological abnormalities, a variety of genetic causes, and different clinical presentations. Brain magnetic resonance imaging has been of great help in determining the exact morphologies of cortical malformations. The hypothetical mechanisms of malformation include interruptions during the formation of cerebral cortex in the form of viral infection, genetic causes, and vascular events. Recent remarkable developments in genetic analysis methods have improved our understanding of these pathological mechanisms. The present review will discuss normal cortical development, the current proposed malformation classifications, and the diagnostic approach for malformations of cortical development. PMID:28203254

  9. Lineage-specific laminar organization of cortical GABAergic interneurons.

    Science.gov (United States)

    Ciceri, Gabriele; Dehorter, Nathalie; Sols, Ignasi; Huang, Z Josh; Maravall, Miguel; Marín, Oscar

    2013-09-01

    In the cerebral cortex, pyramidal cells and interneurons are generated in distant germinal zones, and so the mechanisms that control their precise assembly into specific microcircuits remain an enigma. Here we report that cortical interneurons labeled at the clonal level do not distribute randomly but rather have a strong tendency to cluster in the mouse neocortex. This behavior is common to different classes of interneurons, independently of their origin. Interneuron clusters are typically contained within one or two adjacent cortical layers, are largely formed by isochronically generated neurons and populate specific layers, as revealed by unbiased hierarchical clustering methods. Our results suggest that different progenitor cells give rise to interneurons populating infra- and supragranular cortical layers, which challenges current views of cortical neurogenesis. Thus, specific lineages of cortical interneurons seem to be produced to primarily mirror the laminar structure of the cerebral cortex, rather than its columnar organization.

  10. Transient cortical blindness after coronary angiography.

    Science.gov (United States)

    Alp, B N; Bozbuğa, N; Tuncer, M A; Yakut, C

    2009-01-01

    Transient cortical blindness is rarely encountered after angiography of native coronary arteries or bypass grafts. This paper reports a case of transient cortical blindness that occurred 72 h after coronary angiography in a 56-year old patient. This was the patient's fourth exposure to contrast medium. Neurological examination demonstrated cortical blindness and the absence of any focal neurological deficit. A non-contrast-enhanced computed tomographic scan of the brain revealed bilateral contrast enhancement in the occipital lobes and no evidence of cerebral haemorrhage, and magnetic resonance imaging of the brain showed no pathology. Sight returned spontaneously within 4 days and his vision gradually improved. A search of the current literature for reported cases of transient cortical blindness suggested that this is a rarely encountered complication of coronary angiography.

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

    Directory of Open Access Journals (Sweden)

    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

  12. 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

  13. Cortical Visual Impairment

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Cortical Visual Impairment En Español Read in Chinese What is cortical visual impairment? Cortical visual impairment (CVI) is a decreased visual ...

  14. Cerebral Palsy

    Science.gov (United States)

    Cerebral palsy is a group of disorders that affect a person's ability to move and to maintain balance ... do not get worse over time. People with cerebral palsy may have difficulty walking. They may also have ...

  15. Cerebral malaria Malaria cerebral

    OpenAIRE

    Silvia Blair Trujillo; Carlos Hugo Zapata Zapata

    2003-01-01

    Is the most common complication of P. falciparum malaria; nearly 90% of people who have suffered CM can recover without neurological problems. Currently there are four hypotheses that explain pathogenesis of CM: cytoadherence and sequestering of parasitized red blood cells to cerebral capillaries; rosette formation and parasitized red blood cells agglutination; production of cytokines and activation of second messengers and opening of the blood-brain barrier. However the main question remains...

  16. Incidental Cerebral Microbleeds and Cerebral Blood Flow in Elderly Individuals.

    Science.gov (United States)

    Gregg, Nicholas M; Kim, Albert E; Gurol, M Edip; Lopez, Oscar L; Aizenstein, Howard J; Price, Julie C; Mathis, Chester A; James, Jeffrey A; Snitz, Beth E; Cohen, Ann D; Kamboh, M Ilyas; Minhas, Davneet; Weissfeld, Lisa A; Tamburo, Erica L; Klunk, William E

    2015-09-01

    Cerebral microbleeds (CMBs) are collections of blood breakdown products that are a common incidental finding in magnetic resonance imaging of elderly individuals. Cerebral microbleeds are associated with cognitive deficits, but the mechanism is unclear. Studies show that individuals with CMBs related to symptomatic cerebral amyloid angiopathy have abnormal vascular reactivity and cerebral blood flow (CBF), but, to our knowledge, abnormalities in cerebral blood flow have not been reported for healthy individuals with incidental CMBs. To evaluate the association of incidental CMBs with resting-state CBF, cerebral metabolism, cerebrovascular disease, β-amyloid (Aβ), and cognition. A cross-sectional study of 55 cognitively normal individuals with a mean (SD) age of 86.8 (2.7) years was conducted from May 1, 2010, to May 1, 2013, in an academic medical center in Pittsburgh; data analysis was performed between June 10, 2013, and April 9, 2015. 3-Tesla magnetic resonance imaging was performed with susceptibility-weighted imaging or gradient-recalled echo to assess CMBs, arterial spin labeling for CBF, and T1- and T2-weighted imaging for atrophy, white matter hyperintensities, and infarcts. Positron emission tomography was conducted with fluorodeoxyglucose to measure cerebral metabolism and Pittsburgh compound B for fibrillar Aβ. Neuropsychological evaluation, including the Clinical Dementia Rating scale, was performed. Magnetic resonance images were rated for the presence and location of CMBs. Lobar CMBs were subclassified as cortical or subcortical. Measurements of CBF, metabolism, and Aβ were compared with the presence and number of CMBs with voxelwise and region-of-interest analyses. The presence of cortical CMBs was associated with significantly reduced CBF in multiple regions on voxelwise and region-of-interest analyses (percentage difference in global CBF, -25.3%; P = .0003), with the largest reductions in the parietal cortex (-37.6%; P CMBs showed a

  17. Resonance circuits for adiabatic circuits

    Directory of Open Access Journals (Sweden)

    C. Schlachta

    2003-01-01

    Full Text Available One of the possible techniques to reduces the power consumption in digital CMOS circuits is to slow down the charge transport. This slowdown can be achieved by introducing an inductor in the charging path. Additionally, the inductor can act as an energy storage element, conserving the energy that is normally dissipated during discharging. Together with the parasitic capacitances from the circuit a LCresonant circuit is formed.

  18. Cerebral malaria Malaria cerebral

    Directory of Open Access Journals (Sweden)

    Silvia Blair Trujillo

    2003-03-01

    Full Text Available Is the most common complication of P. falciparum malaria; nearly 90% of people who have suffered CM can recover without neurological problems. Currently there are four hypotheses that explain pathogenesis of CM: cytoadherence and sequestering of parasitized red blood cells to cerebral capillaries; rosette formation and parasitized red blood cells agglutination; production of cytokines and activation of second messengers and opening of the blood-brain barrier. However the main question remains to be answered; how the host-parasite interaction in the vascular space interferes transiently with cerebral function? Recently, the beta amyloid precursor peptide has been employed as marker of neural injury in CM. It is expected that the beta amyloid precursor peptide will help to understand the pathogenesis of CM in complicated patients of endemic areas of Colombia. La malaria Cerebral (MC es la complicación más frecuente de la malaria por P. falciparum; aproximadamente el 90% de las personas que la han padecido se recuperan completamente sin secuelas neurológicas. Aún no se conoce con claridad su patogénesis pero se han postulado cuatro hipótesis o mecanismos posibles: 1 citoadherencia y secuestro de glóbulos rojos parasitados en la microvasculatura cerebral; 2 formación de rosetas y aglutinación de glóbulos rojos parasitados; 3 producción de citoquinas y activación de segundos mensajeros y, 4 apertura de la barrera hematoencefálica. Sin embargo, queda un interrogante sin resolver aún: ¿qué proceso se lleva a cabo para que el parásito, desde el espacio microvascular, pueda interferir transitoriamente con la función cerebral? Recientemente se ha utilizado el precursor de la proteína b-Amiloide como un marcador de daño neuronal en MC; este precursor será de gran ayuda en futuras investigaciones realizadas en nuestro medio que aporten información para comprender la patogénesis de la MC.

  19. Contrast MR imaging of acute cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Kogame, Saeko; Syakudo, Miyuki; Inoue, Yuichi (Osaka City Univ. (Japan). Faculty of Medicine) (and others)

    1992-04-01

    Thirty patients with acute and subacute cerebral infarction (13 and 17 deep cerebral infarction) were studied with 0.5 T MR unit before and after intravenous injection of Gd-DTPA. Thirteen patients were studied within 7 days after neurological ictus, 17 patients were studied between 7 and 14 days. Two types of abnormal enhancement, cortical arterial and parenchymal enhancement, were noted. The former was seen in 3 of 4 cases of very acute cortical infarction within 4 days after clinical ictus. The latter was detected in all 7 cases of cortical infarction after the 6th day of the ictus, and one patient with deep cerebral infarction at the 12th day of the ictus. Gd-DTPA enhanced MR imaging seems to detect gyral enhancement earlier compared with contrast CT, and depict intra-arterial sluggish flow which was not expected to see on contrast CT scans. (author).

  20. Altered cortical activation from the hand after facial Botulinum Toxin treatment

    OpenAIRE

    Haenzi, Sara; Stefanics, Gabor; Lanaras, Tatjana; Calcagni, Maurizio; Ghosh, Arko

    2014-01-01

    Plastic interactions between face and hand cortical tactile circuits occur after severe injuries that affect the hand such as in amputation or spinal cord injury. However, whether loss of facial movements alters the cortical circuits involved in processing tactile inputs from the hand remains unknown. In this prospective observational study we used electroencephalography (EEG) to measure cortical activity evoked by tactile stimulation of the hands before and after botulinum toxin-A-induced fa...

  1. EDT,a tetrahydroacridine derivative inhibits cerebral ischemia and protects rat cortical neurons against glutamate-induced cytotoxicity%四氢吖啶类衍生物EDT抑制脑缺血及保护大鼠皮层神经元抗谷氨酸诱发的细胞毒性

    Institute of Scientific and Technical Information of China (English)

    盛瑞; 刘国卿

    2003-01-01

    目的:考察9-(4-乙氧羰基苯氧基)-6,7-二甲氧基-1,2,3,4-四氢吖啶盐酸盐(EDT)对大鼠局灶性脑缺血及谷氨酸(Glu)和硝普钠(SNP)致鼠皮层神经元损伤的作用.方法:灼断小鼠一侧大脑中动脉形成局灶性脑缺血模型,用氯化三苯基四氮唑(TTC)染色法测定脑梗塞率同时对神经症状进行评分.在原代培养的大鼠皮层神经细胞,采用MTT比色法,测定培养质内LDH及NO释放量.结果:EDT 2.5、5和10mg/kg及尼莫地平2 mg/kg灌胃5 d显著改善局灶性脑缺血小鼠的神经运动功能,缩小脑梗塞范围.在原代培养的鼠皮层神经细胞,EDT 0.01-3 μmol/L浓度依赖地对抗Glu诱发的NO过量形成,并提高MTT微量比色值,同时,减少SNP引起的LDH过量释放,提高细胞存活率.结论:EDT能有效对抗脑缺血损伤,其神经保护作用可能是通过阻断Glu受体及抑制N0生成而实现的.%AIM: To study the effects of 9-(4-ethoxycarbonylyphenoxy)-6,7-dimethoxy-1,2,3,4-tetrahydroacridine (EDT) on cerebral ischemia and glutamic acid (Glu) and sodium nitroprusside (SNP)-induced neurocytotoxicity in primary cortical culture. METHODS: Focal cerebral ischemia was produced by permanent occlusion of left middle cerebral artery (MCA) in mice. The infarct tissue was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining technique. The extent of neurological deficits was evaluated. In primary cortical culture, colorimetric MTT assay was used to determine cell survival rate, and leakage of LDH and NO release assay were measured. RESULTS: In focal cerebral ischemia, pretreatment with EDT 2.5, 5, and 10 mg/kg and nimodipine 2 mg/kg for 5 d effectively improved the abnormal neurological symptoms and reduced the infarct rate. In primary cortical culture, EDT 0.01-3 μmol/L concentration-dependently attenuated NO release induced by Glu 500 μmol/L and increased the cell survival. It also remarkably reduced the LDH excessive efflux. CONCLUSION: EDT possessed

  2. GATING CIRCUITS

    Science.gov (United States)

    Merrill, L.C.

    1958-10-14

    Control circuits for vacuum tubes are described, and a binary counter having an improved trigger circuit is reported. The salient feature of the binary counter is the application of the input signal to the cathode of each of two vacuum tubes through separate capacitors and the connection of each cathode to ground through separate diodes. The control of the binary counter is achieved in this manner without special pulse shaping of the input signal. A further advantage of the circuit is the simplicity and minimum nuruber of components required, making its use particularly desirable in computer machines.

  3. Localization of cortical areas activated by thinking

    DEFF Research Database (Denmark)

    Roland, P E; Friberg, L

    1985-01-01

    These experiments were undertaken to demonstrate that pure mental activity, thinking, increases the cerebral blood flow and that different types of thinking increase the regional cerebral blood flow (rCBF) in different cortical areas. As a first approach, thinking was defined as brain work...... study was taken with the subjects at rest. Then the rCBF was measured during three different simple algorithm tasks, each consisting of retrieval of a specific memory followed by a simple operation on the retrieved information. Once started, the information processing went on in the brain without any...... that they started at their front door and then walked alternatively to the left or the right each time they reached a corner. The rCBF increased only in homotypical cortical areas during thinking. The areas in the superior prefrontal cortex increased their rCBF equivalently during the three types of thinking...

  4. The enemy within: propagation of aberrant corticostriatal learning to cortical function in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Jeff A Beeler

    2013-09-01

    Full Text Available Motor dysfunction in Parkinson’s disease is believed to arise primarily from pathophysiology in the dorsal striatum and its related corticostriatal and thalamostriatal circuits during progressive dopamine denervation. One function of these circuits is to provide a filter that selectively facilitates or inhibits cortical activity to optimize cortical processing, making motor responses rapid and efficient. Corticostriatal synaptic plasticity mediates the learning that underlies this performance-optimizing filter. Under dopamine denervation, corticostriatal plasticity is altered, resulting in aberrant learning that induces inappropriate basal ganglia filtering that impedes rather than optimizes cortical processing. Human imaging suggests that increased cortical activity may compensate for striatal dysfunction in PD patients. In this Perspective article, we consider how aberrant learning at corticostriatal synapses may impair cortical processing and learning and undermine potential cortical compensatory mechanisms. Blocking or remediating aberrant corticostriatal plasticity may protect cortical function and support cortical compensatory mechanisms mitigating the functional decline associated with progressive dopamine denervation.

  5. Imaging characteristics of two patients with isolated cortical venous thrombosis

    Institute of Scientific and Technical Information of China (English)

    Shunchang Han; Hui Zhang; Guoguang Fan; Baohai Sun

    2008-01-01

    BACKGROUND:Over the past twenty years, improvements in neuroimaging have greatly improved the ability to diagnose cerebral venous sinus thrombosis, as well as isolated cortical venous thrombosis. Neuroimaging allows for variations to be detected in the cortical vein and venous sinus. Diagnosis of thromboses in the venous system should not depend entirely on angiography of undeveloped veins or venous sinus. Currently, the combination of magnetic resonance imaging and magnetic resonance venography is the gold standard for diagnosing cerebral venous sinus thrombosis, rather than digital subtraction angiography. This article summarizes clinical manifestations, results from computed tomography and magnetic resonance imaging in two cases of isolated cortical venous thrombosis, analyzed relevant literature, and discussed the clinical and imaging characteristics of isolated cortical venous thromboses.

  6. Assessment of cortical maturation with prenatal MRI. Part I: normal cortical maturation

    Energy Technology Data Exchange (ETDEWEB)

    Fogliarini, Celine [Faculte Timone, Centre de Resonance Magnetique Biologique et Medicale, Marseille (France); Chaumoitre, Katia [Hopital Nord, Department of Radiology, Marseille (France); Chapon, Frederique; Levrier, Olivier; Girard, Nadine [Hopital Timone, Department of Neuroradiology, Marseille Cedex 5 (France); Fernandez, Carla; Figarella-Branger, Dominique [Hopital Timone, Department of Pathology, Marseille (France)

    2005-08-01

    Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa. (orig.)

  7. A longitudinal study of cerebral glucose metabolism, MRI, and disability in patients with MS

    DEFF Research Database (Denmark)

    Blinkenberg, M; Jensen, C.V.; Holm, S

    1999-01-01

    (Expanded Disability Status Scale [EDSS]) over a period of approximately 2 years (three examinations). CMRglc was calculated using PET and 18-fluorodeoxyglucose (FDG). RESULTS: The global cortical CMRglc decreased with time (p... and parietal cortical areas. There was a statistically significant increase of disability (pEDSS. CONCLUSIONS: Global cortical cerebral metabolism in MS is decreased significantly during a 2...

  8. Transient cortical blindness after coronary artery angiography.

    Science.gov (United States)

    Terlecki, Michał; Wojciechowska, Wiktoria; Rajzer, Marek; Jurczyszyn, Artur; Bazan-Socha, Stanisława; Bryniarski, Leszek; Czarnecka, Danuta

    2013-01-01

    Coronary angiography is the current gold standard for the diagnosis of ischemic heart disease and therefore the prevalence of percutaneous coronary procedures such as angiography and angioplasty is high. The occurrence of cerebral complications after coronary angiography and coronary angioplasty is low and it mainly includes transient ischemic attack and stroke. The prevalence of transient cortical blindness after X-ray contrast media is low and it is usually seen after cerebral angiography. Until now only a few cases of transient cortical blindness have been described after coronary artery angiography. Regarding the spread of coronary angiography worldwide and in Poland this complication is uniquely rare. A 32-year-old man with multiple extrasystolic ventricular arrhythmia suggesting Brugada syndrome diagnosis according to morphology of the left bundle branch block and with decreased left ventricular ejection fraction was admitted to the First Department of Cardiology and Hypertension, Medical College of the Jagiellonian University in Krakow. Coronary angiography was performed in order to exclude ischemic etiology of the observed abnormalities. No arteriosclerotic lesions were found in coronary arteries. Transient cortical blindness was observed directly after angiography which may have been caused by the neurotoxic effect of the used X-ray contrast medium. In ophthalmologic and neurologic examination as well as in the cerebral computed tomography scan no pathologies were found. Visual impairment disappeared totally within several hours.

  9. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed

  10. Associations between cortical thickness and general intelligence in children, adolescents and young adults

    NARCIS (Netherlands)

    K. Menary (Kyle); P.F. Collins (Paul); J.N. Porter (James); R.L. Muetzel (Ryan); E.A. Olson (Elizabeth); V. Kumar (Vipin); D. Steinbach; K.O. Lim (Kelvin); M. Luciana (Monica)

    2013-01-01

    textabstractNeuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throug

  11. Cortical spreading depression and involvement of the motor cortex, auditory cortex, and cerebellum in eyeblink classical conditioning of the rabbit.

    Science.gov (United States)

    Case, Gilbert R; Lavond, David G; Thompson, Richard F

    2002-09-01

    The interrelationships of cerebellar and cerebral neural circuits in the eyeblink paradigm were explored with the controlled application of cortical spreading depression (CSD) and lidocaine in the New Zealand albino rabbit. The initial research focus was directed toward the involvement of the motor cortex in the conditioned eyeblink response. However, CSD timing and triangulation results indicate that other areas in the cerebral cortex, particularly the auditory cortex (acoustic conditioned stimulus), appear to be critical for the CSD effect on the eyeblink response. In summary: (1) CSD can be elicited, monitored, and timed and its side effects controlled in 97% of awake rabbits in the right and/or left cerebral hemisphere(s) during eyeblink conditioning. (2) The motor cortex appears to play little or no part in classical conditioning of the eyeblink in the rabbit in the delay paradigm. (3) Inactivating the auditory cortex with CSD or lidocaine temporarily impairs the conditioned response during the first 5 to 15 days of training, but has little effect past that point.

  12. Neurodynamics of somatosensory cortices studied by magnetoencephelography.

    Science.gov (United States)

    Kishida, Kuniharu

    2013-09-01

    From the viewpoint of statistical inverse problems, identification of transfer functions in feedback models is applied for neurodynamics of somatosensory cortices, and brain communication among active regions can be expressed in terms of transfer functions. However, brain activities have been investigated mainly by averaged waveforms in the conventional magnetoencephalography analysis, and thus brain communication among active regions has not yet been identified. It is shown that brain communication among two more than three brain regions is determined, when fluctuations related to concatenate averaged waveforms can be obtained by using a suitable blind source separation method. In blind identification of feedback model, some transfer functions or their impulse responses between output variables of current dipoles corresponding to active regions are identified from reconstructed time series data of fluctuations by the method of inverse problem. Neurodynamics of somatosensory cortices in 5 Hz median nerve stimuli can be shown by cerebral communication among active regions of somatosensory cortices in terms of impulse responses of feedback model.

  13. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  14. Ischemic cerebral changes in the chronic chagasic cardiopathy

    Directory of Open Access Journals (Sweden)

    José Eymard Homem Pitella

    1984-06-01

    Full Text Available The pathological systematized study of the brain of 31 cases of the chronic cardiac form of Chagas' disease was undertaken. Elective parenchymatous necrosis was found in 64.5% of cases, mainly in cerebellar Purkinje cells, and in thalamic nuclei. Also found were multiple foci of old micronecrosis (51.6% mostly in the cerebral cortex, old cerebral infarcts (22.6%, cortical laminar necrosis (16.1% and cerebral cortical atrophy (3.2%. These findings are not specific and can be explained by thromboembolic phenomena and hypoxemia following from congestive heart failure and disturbances of the cardiac rhythm.

  15. 脑血流低灌注老龄大鼠中脑皮质血流的改变与血清总胆固醇和高密度脂蛋白的动态变化%Dynamic changes of cortical blood flow and serum total cholesterol and high density lipoprotein in brains of aging rat during cerebral hypoperfusion

    Institute of Scientific and Technical Information of China (English)

    王林辉; 田茗源; 滕志朋; 王晨; 李昱

    2012-01-01

    目的:通过建立脑血流低灌注模型,观察老龄大鼠脑血流的变化以及在脑血流低灌注下血清中总胆固醇(Total cholesterol,TC)和高密度脂蛋白(High density lipoprotein,HDL)的动态变化.方法:采用持久性双侧颈总动脉结扎法(2Vo)致老龄大鼠脑血流灌注不足,测定术后7、14、21、28d大鼠脑皮质血流;检测、比较术后不同时间段大鼠血清中TC和HDL浓度差异.结果:术后第14天大鼠脑颞区血流出现明显减少;术后21、28d大鼠脑局部皮质血管有再生侧支形成,大鼠脑颞区血流仍未恢复;术后第14天血清中HDL、TC含量明显高于假手术组(P<0.05),随着缺血时间延长,又逐渐降低.结论:血清TC和HDL浓度在脑缺血灌注不足的不同时间段经历了先增强后减弱的动态变化,提示脑血流低灌注老龄大鼠因大脑血流灌注不足可出现体内胆固醇代谢失衡并出现应激调节现象.%Objective: To investigate the change of cortical blood flow and the dynamic changes of serum total cholesterol(TC ) and high density lipoprotein(HDL) in brains of aging rat during cerebral ischemic injury. Methods:The model of aging rats with cerebral hy-poperfusion was successfully constructed by persistent bilateral common carotid artery ligation(2V0). The cortical blood flow and the concentration of serum TC and HDL at different time points were determined and compared. Results: Compared with the sham-operated group,the temporal blood flow was significantly decreased in 14 d group. But the collateral vessels were gradually regenerated and formed in local brain,while the temporal blood flow was restored in 21 d and 28 d group. The concentration of HDL and TC was significantly higher in 14 d group than in the sham-operated group (P<0.05), and both of them were decreased with the extention of ischemia time. Conclusions:The serum TC and HDL concentration undergo dynamic changes-increasing first and then decreasing during the process

  16. Cortical Neural Computation by Discrete Results Hypothesis

    Science.gov (United States)

    Castejon, Carlos; Nuñez, Angel

    2016-01-01

    One of the most challenging problems we face in neuroscience is to understand how the cortex performs computations. There is increasing evidence that the power of the cortical processing is produced by populations of neurons forming dynamic neuronal ensembles. Theoretical proposals and multineuronal experimental studies have revealed that ensembles of neurons can form emergent functional units. However, how these ensembles are implicated in cortical computations is still a mystery. Although cell ensembles have been associated with brain rhythms, the functional interaction remains largely unclear. It is still unknown how spatially distributed neuronal activity can be temporally integrated to contribute to cortical computations. A theoretical explanation integrating spatial and temporal aspects of cortical processing is still lacking. In this Hypothesis and Theory article, we propose a new functional theoretical framework to explain the computational roles of these ensembles in cortical processing. We suggest that complex neural computations underlying cortical processing could be temporally discrete and that sensory information would need to be quantized to be computed by the cerebral cortex. Accordingly, we propose that cortical processing is produced by the computation of discrete spatio-temporal functional units that we have called “Discrete Results” (Discrete Results Hypothesis). This hypothesis represents a novel functional mechanism by which information processing is computed in the cortex. Furthermore, we propose that precise dynamic sequences of “Discrete Results” is the mechanism used by the cortex to extract, code, memorize and transmit neural information. The novel “Discrete Results” concept has the ability to match the spatial and temporal aspects of cortical processing. We discuss the possible neural underpinnings of these functional computational units and describe the empirical evidence supporting our hypothesis. We propose that fast

  17. Change in the cortical complexity of spinocerebellar ataxia type 3 appears earlier than clinical symptoms.

    Science.gov (United States)

    Wang, Tzu-Yun; Jao, Chii-Wen; Soong, Bing-Wen; Wu, Hsiu-Mei; Shyu, Kuo-Kai; Wang, Po-Shan; Wu, Yu-Te

    2015-01-01

    Patients with spinocerebellar ataxia type 3 (SCA3) have exhibited cerebral cortical involvement and various mental deficits in previous studies. Clinically, conventional measurements, such as the Mini-Mental State Examination (MMSE) and electroencephalography (EEG), are insensitive to cerebral cortical involvement and mental deficits associated with SCA3, particularly at the early stage of the disease. We applied a three-dimensional fractal dimension (3D-FD) method, which can be used to quantify the shape complexity of cortical folding, in assessing cortical degeneration. We evaluated 48 genetically confirmed SCA3 patients by employing clinical scales and magnetic resonance imaging and using 50 healthy participants as a control group. According to the Scale for the Assessment and Rating of Ataxia (SARA), the SCA3 patients were diagnosed with cortical dysfunction in the cerebellar cortex; however, no significant difference in the cerebral cortex was observed according to the patients' MMSE ratings. Using the 3D-FD method, we determined that cortical involvement was more extensive than involvement of traditional olivopontocerebellar regions and the corticocerebellar system. Moreover, the significant correlation between decreased 3D-FD values and disease duration may indicate atrophy of the cerebellar cortex and cerebral cortex in SCA3 patients. The change of the cerebral complexity in the SCA3 patients can be detected throughout the disease duration, especially it becomes substantial at the late stage of the disease. Furthermore, we determined that atrophy of the cerebral cortex may occur earlier than changes in MMSE scores and EEG signals.

  18. Change in the cortical complexity of spinocerebellar ataxia type 3 appears earlier than clinical symptoms.

    Directory of Open Access Journals (Sweden)

    Tzu-Yun Wang

    Full Text Available Patients with spinocerebellar ataxia type 3 (SCA3 have exhibited cerebral cortical involvement and various mental deficits in previous studies. Clinically, conventional measurements, such as the Mini-Mental State Examination (MMSE and electroencephalography (EEG, are insensitive to cerebral cortical involvement and mental deficits associated with SCA3, particularly at the early stage of the disease. We applied a three-dimensional fractal dimension (3D-FD method, which can be used to quantify the shape complexity of cortical folding, in assessing cortical degeneration. We evaluated 48 genetically confirmed SCA3 patients by employing clinical scales and magnetic resonance imaging and using 50 healthy participants as a control group. According to the Scale for the Assessment and Rating of Ataxia (SARA, the SCA3 patients were diagnosed with cortical dysfunction in the cerebellar cortex; however, no significant difference in the cerebral cortex was observed according to the patients' MMSE ratings. Using the 3D-FD method, we determined that cortical involvement was more extensive than involvement of traditional olivopontocerebellar regions and the corticocerebellar system. Moreover, the significant correlation between decreased 3D-FD values and disease duration may indicate atrophy of the cerebellar cortex and cerebral cortex in SCA3 patients. The change of the cerebral complexity in the SCA3 patients can be detected throughout the disease duration, especially it becomes substantial at the late stage of the disease. Furthermore, we determined that atrophy of the cerebral cortex may occur earlier than changes in MMSE scores and EEG signals.

  19. CT findings in patients with cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Konno, K. (Akita Univ. (Japan))

    1982-01-01

    Clinical findings and CT findings in 73 cases of cerebral palsy were studied. The causes of cerebral palsy were presumed to be as follows: abnormal cerebral development (36%), asphyxial delivery (34%), and immature delivery (19%), etc. CT findings were abnormal in 58% of the 73 cases, 83% of the spastic tetraplegia patients and all of the spastic hemiplegia patients showed abnormal CT findings. All the patients with spastic monoplegia presented normal CT findings. In 75% of the spastic hemiplegia cases, the CT abnormalities were due to cerebral parenchymal abnormality such as porencephaly and regional low absorption. In cases of spastic tetraplegia, cerebral parenchymal abnormality was found only in 10%. Cortical atrophy was found only in 15 of the 73 cases, whereas central atrophy was found in 36 cases.

  20. Estimation of the effective and functional human cortical connectivity with structural equation modeling and directed transfer function applied to high-resolution EEG.

    Science.gov (United States)

    Astolfi, Laura; Cincotti, Febo; Mattia, Donatella; Salinari, Serenella; Babiloni, Claudio; Basilisco, Alessandra; Rossini, Paolo Maria; Ding, Lei; Ni, Ying; He, Bin; Marciani, Maria Grazia; Babiloni, Fabio

    2004-12-01

    Different brain imaging devices are presently available to provide images of the human functional cortical activity, based on hemodynamic, metabolic or electromagnetic measurements. However, static images of brain regions activated during particular tasks do not convey the information of how these regions are interconnected. The concept of brain connectivity plays a central role in the neuroscience, and different definitions of connectivity, functional and effective, have been adopted in literature. While the functional connectivity is defined as the temporal coherence among the activities of different brain areas, the effective connectivity is defined as the simplest brain circuit that would produce the same temporal relationship as observed experimentally among cortical sites. The structural equation modeling (SEM) is the most used method to estimate effective connectivity in neuroscience, and its typical application is on data related to brain hemodynamic behavior tested by functional magnetic resonance imaging (fMRI), whereas the directed transfer function (DTF) method is a frequency-domain approach based on both a multivariate autoregressive (MVAR) modeling of time series and on the concept of Granger causality. This study presents advanced methods for the estimation of cortical connectivity by applying SEM and DTF on the cortical signals estimated from high-resolution electroencephalography (EEG) recordings, since these signals exhibit a higher spatial resolution than conventional cerebral electromagnetic measures. To estimate correctly the cortical signals, we used a subject's multicompartment head model (scalp, skull, dura mater, cortex) constructed from individual MRI, a distributed source model and a regularized linear inverse source estimates of cortical current density. Before the application of SEM and DTF methodology to the cortical waveforms estimated from high-resolution EEG data, we performed a simulation study, in which different main factors

  1. Local connections of excitatory neurons in motor-associated cortical areas of the rat

    Science.gov (United States)

    Kaneko, Takeshi

    2013-01-01

    In spite of recent progress in brain sciences, the local circuit of the cerebral neocortex, including motor areas, still remains elusive. Morphological works on excitatory cortical circuitry from thalamocortical (TC) afferents to corticospinal neurons (CSNs) in motor-associated areas are reviewed here. First, TC axons of motor thalamic nuclei have been re-examined by the single-neuron labeling method. There are middle layer (ML)-targeting and layer (L) 1-preferring TC axon types in motor-associated areas, being analogous to core and matrix types, respectively, of Jones (1998) in sensory areas. However, the arborization of core-like motor TC axons spreads widely and disregards the columnar structure that is the basis of information processing in sensory areas, suggesting that motor areas adopt a different information-processing framework such as area-wide laminar organization. Second, L5 CSNs receive local excitatory inputs not only from L2/3 pyramidal neurons but also from ML spiny neurons, the latter directly processing cerebellar information of core-like TC neurons (TCNs). In contrast, basal ganglia information is targeted to apical dendrites of L2/3 and L5 pyramidal neurons through matrix TCNs. Third, L6 corticothalamic neurons (CTNs) are most densely innervated by ML spiny neurons located just above CTNs. Since CTNs receive only weak connections from L2/3 and L5 pyramidal neurons, the TC recurrent circuit composed of TCNs, ML spiny neurons and CTNs appears relatively independent of the results of processing in L2/3 and L5. It is proposed that two circuits sharing the same TC projection and ML neurons are embedded in the neocortex: one includes L2/3 and L5 neurons, processes afferent information in a feedforward way and sends the processed information to other cortical areas and subcortical regions; and the other circuit participates in a dynamical system of the TC recurrent circuit and may serve as the basis of autonomous activity of the neocortex. PMID

  2. Bilateral Cerebellar Cortical Dysplasia without Other Malformations: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jung Seok; Ahn Kook Jin; Kim, Jee Young; Lee, Sun Jin; Park, Jeong Mi [Catholic University Yeouido St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of)

    2010-06-15

    Recent advances in MRI have revealed congenital brain malformations and subtle developmental abnormalities of the cerebral and cerebellar cortical architecture. Typical cerebellar cortical dysplasia as a newly categorized cerebellar malformation, has been seen in patients with Fukuyama congenital muscular dystrophy. Cerebellar cortical dysplasia occurs at the embryonic stage and is often observed in healthy newborns. It is also incidentally and initially detected in adults without symptoms. To the best of our knowledge, cerebellar dysplasia without any related disorders is very rare. We describe the MRI findings in one patient with disorganized foliation of both cerebellar hemispheres without a related disorder or syndrome

  3. Controllable circuit

    DEFF Research Database (Denmark)

    2010-01-01

    A switch-mode power circuit comprises a controllable element and a control unit. The controllable element is configured to control a current in response to a control signal supplied to the controllable element. The control unit is connected to the controllable element and provides the control...

  4. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  5. Neuronal networks and mediators of cortical neurovascular coupling responses in normal and altered brain states.

    Science.gov (United States)

    Lecrux, C; Hamel, E

    2016-10-05

    Brain imaging techniques that use vascular signals to map changes in neuronal activity, such as blood oxygenation level-dependent functional magnetic resonance imaging, rely on the spatial and temporal coupling between changes in neurophysiology and haemodynamics, known as 'neurovascular coupling (NVC)'. Accordingly, NVC responses, mapped by changes in brain haemodynamics, have been validated for different stimuli under physiological conditions. In the cerebral cortex, the networks of excitatory pyramidal cells and inhibitory interneurons generating the changes in neural activity and the key mediators that signal to the vascular unit have been identified for some incoming afferent pathways. The neural circuits recruited by whisker glutamatergic-, basal forebrain cholinergic- or locus coeruleus noradrenergic pathway stimulation were found to be highly specific and discriminative, particularly when comparing the two modulatory systems to the sensory response. However, it is largely unknown whether or not NVC is still reliable when brain states are altered or in disease conditions. This lack of knowledge is surprising since brain imaging is broadly used in humans and, ultimately, in conditions that deviate from baseline brain function. Using the whisker-to-barrel pathway as a model of NVC, we can interrogate the reliability of NVC under enhanced cholinergic or noradrenergic modulation of cortical circuits that alters brain states.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.

  6. Functioning of Circuits Connecting Thalamus and Cortex.

    Science.gov (United States)

    Sherman, S Murray

    2017-03-16

    Glutamatergic pathways in thalamus and cortex are divided into two distinct classes: driver, which carries the main information between cells, and modulator, which modifies how driver inputs function. Identifying driver inputs helps to reveal functional computational circuits, and one set of such circuits identified by this approach are cortico-thalamo-cortical (or transthalamic corticocortical) circuits. This, in turn, leads to the conclusion that there are two types of thalamic relay: first order nuclei (such as the lateral geniculate nucleus) that relay driver input from a subcortical source (i.e., retina), and higher order nuclei (such as the pulvinar) which are involved in these transthalamic pathways by relaying driver input from layer 5 of one cortical area to another. This thalamic division is also seen in other sensory pathways and beyond these so that most of thalamus by volume consists of higher-order relays. Many, and perhaps all, direct driver connections between cortical areas are paralleled by an indirect cortico-thalamo-cortical (transthalamic) driver route involving higher order thalamic relays. Such thalamic relays represent a heretofore unappreciated role in cortical functioning, and this assessment challenges and extends conventional views regarding both the role of thalamus and mechanisms of corticocortical communication. Finally, many and perhaps the vast majority of driver inputs relayed through thalamus arrive via branching axons, with extrathalamic targets often being subcortical motor centers. This raises the possibility that inputs relayed by thalamus to cortex also serve as efference copies, and this may represent an important feature of information relayed up the cortical hierarchy via transthalamic circuits. © 2017 American Physiological Society. Compr Physiol 7:713-739, 2017.

  7. The origin of cortical neurons

    Directory of Open Access Journals (Sweden)

    J.G. Parnavelas

    2002-12-01

    Full Text Available Neurons of the mammalian cerebral cortex comprise two broad classes: pyramidal neurons, which project to distant targets, and the inhibitory nonpyramidal cells, the cortical interneurons. Pyramidal neurons are generated in the germinal ventricular zone, which lines the lateral ventricles, and migrate along the processes of radial glial cells to their positions in the developing cortex in an `inside-out' sequence. The GABA-containing nonpyramidal cells originate for the most part in the ganglionic eminence, the primordium of the basal ganglia in the ventral telencephalon. These cells follow tangential migratory routes to enter the cortex and are in close association with the corticofugal axonal system. Once they enter the cortex, they move towards the ventricular zone, possibly to obtain positional information, before they migrate radially in the direction of the pial surface to take up their positions in the developing cortex. The mechanisms that guide interneurons throughout these long and complex migratory routes are currently under investigation.

  8. Meningeal and cortical grey matter pathology in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Gh Popescu Bogdan F

    2012-03-01

    Full Text Available Abstract Although historically considered a disease primarily affecting the white matter of the central nervous system, recent pathological and imaging studies have established that cortical demyelination is common in multiple sclerosis and more extensive than previously appreciated. Subpial, intracortical and leukocortical lesions are the three cortical lesion types described in the cerebral and cerebellar cortices of patients with multiple sclerosis. Cortical demyelination may be the pathological substrate of progression, and an important pathologic correlate of irreversible disability, epilepsy and cognitive impairment. Cortical lesions of chronic progressive multiple sclerosis patients are characterized by a dominant effector cell population of microglia, by the absence of macrophagic and leukocytic inflammatory infiltrates, and may be driven in part by organized meningeal inflammatory infiltrates. Cortical demyelination is also present and common in early MS, is topographically associated with prominent meningeal inflammation and may even precede the appearance of classic white matter plaques in some MS patients. However, the pathology of early cortical lesions is different than that of chronic MS in the sense that early cortical lesions are highly inflammatory, suggesting that neurodegeneration in MS occurs on an inflammatory background and raising interesting questions regarding the role of cortical demyelination and meningeal inflammation in initiating and perpetuating the disease process in early MS.

  9. Activity-Dependent Callosal Axon Projections in Neonatal Mouse Cerebral Cortex

    Directory of Open Access Journals (Sweden)

    Yoshiaki Tagawa

    2012-01-01

    Full Text Available Callosal axon projections are among the major long-range axonal projections in the mammalian brain. They are formed during the prenatal and early postnatal periods in the mouse, and their development relies on both activity-independent and -dependent mechanisms. In this paper, we review recent findings about the roles of neuronal activity in callosal axon projections. In addition to the well-documented role of sensory-driven neuronal activity, recent studies using in utero electroporation demonstrated an essential role of spontaneous neuronal activity generated in neonatal cortical circuits. Both presynaptic and postsynaptic neuronal activities are critically involved in the axon development. Studies have begun to reveal intracellular signaling pathway which works downstream of neuronal activity. We also review several distinct patterns of neuronal activity observed in the developing cerebral cortex, which might play roles in activity-dependent circuit construction. Such neuronal activity during the neonatal period can be disrupted by genetic factors, such as mutations in ion channels. It has been speculated that abnormal activity caused by such factors may affect activity-dependent circuit construction, leading to some developmental disorders. We discuss a possibility that genetic mutation in ion channels may impair callosal axon projections through an activity-dependent mechanism.

  10. Efeitos do pentobarbital sódico sobre a atividade elétrica cerebral do rato com lesões da formação reticular mesencefálica Action of sodium pentobarbital on the cortical electrical activity of the rat after lesion of the midbrain reticular formation

    Directory of Open Access Journals (Sweden)

    Walter C. Pereira

    1970-12-01

    Full Text Available Para êste estudo foram empregados 35 ratos da raça Wistar em preparação aguda (24 com lesão bilateral e 11 com lesão unilateral da formação reticular mesencefálica e 18 preparações crônicas. O método empregado na obtenção das preparações foi descrito em trabalho anterior12. O objetivo desta série de experiências foi o de verificar de que maneira o pentobarbital interfere sobre as características da atividade elétrica cortical após lesão da formação reticular mesencefálica. Para tal, em animais preparados agudamente, foram feitas lesões progressivamente mais extensas e o barbitúrico injetado por via intravenosa em doses crescentes. A fim de testar a integridade do sistema reticular ativador ascendente, além de estímulos dolorosos intensos, aplicávamos pulsos de 5 a 10 V, 100 Hz, e 0,1 ms à formação reticular mesencefálica situada abaixo da região lesada. A ausência de reação de alerta cortical (dessincronização nos assegurava que tal sistema havia sido lesado completamente. Nas preparações crônicas o pentobarbital era injetado por via intraperitoneal. Dessas experiências concluimos o seguinte: 1. Aumento da sincronização do eletrocorticograma nos animais com lesões parciais ou totais da formação reticular mesencefálica. 2. Depressão acentuada e precoce da atividade elétrica cerebral nos ratos com lesão muito extensa (comprometendo também a porção ventrobasal do tálamo. 3. Isocronismo da atividade elétrica cortical nos dois hemisférios cerebrais. 4. O pentobarbital parece agir tanto sobre os sistemas ativadores como sobre o sincronizador do eletrocorticograma. As doses pequenas deprimem os primeiros, liberando o segundo, enquanto que as maiores bloqueiam também este último. Sòmente doses muito mais altas é que fazem desaparecer totalmente a atividade do córtex cerebral, que se mostra, portanto, mais resistente à ação da droga.This study was performed on 35 albino rats prepared for

  11. Cortical Reorganization of Language Functioning Following Perinatal Left MCA Stroke

    Science.gov (United States)

    Tillema, Jan-Mendelt; Byars, Anna W.; Jacola, Lisa M.; Schapiro, Mark B.; Schmithorst, Vince J.; Szaflarski, Jerzy P.; Holland, Scott K.

    2008-01-01

    Objective: Functional MRI was used to determine differences in patterns of cortical activation between children who suffered perinatal left middle cerebral artery (MCA) stroke and healthy children performing a silent verb generation task. Methods: Ten children with prior perinatal left MCA stroke (age 6-16 years) and ten healthy age matched…

  12. Vasoespasmo cerebral

    Directory of Open Access Journals (Sweden)

    Antonio A. F. de Salles

    1987-09-01

    Full Text Available Vasoespasmo cerebral ocorre em patologias como enxaqueca, hemorragia subaracnóidea, trauma de crânio, após isquemia e/ou hipoxia. A fisiopatologia do vasoespasmo cerebral nestas patologias não está completamente desvendada. Neste artigo são analisados os fatores neuroquímicos e morfológicos responsáveis pelo controle circulatório cerebral. As alterações circulatórias que seguem a hemorragia subaracnóidea são utilizadas como exemplo. Conclui-se que fatores bioquímicos, fisiológicos e morfológicos são responsáveis pelas manifestações vasculares que ocorrem após a hemorragia subaracnóidea. Alternativas de tratamento do vasoespasmo cerebral são discutidas.

  13. Cognitive consilience: Primate non-primary neuroanatomical circuits underlying cognition

    Directory of Open Access Journals (Sweden)

    Soren Van Hout Solari

    2011-12-01

    Full Text Available Interactions between the cerebral cortex, thalamus, and basal ganglia form the basis ofcognitive information processing in the mammalian brain. Understanding the principles ofneuroanatomical organization in these structures is critical to understanding the functions theyperform and ultimately how the human brain works. We have manually distilled and synthesizedhundreds of primate neuroanatomy facts into a single interactive visualization. The resultingpicture represents the fundamental neuroanatomical blueprint upon which cognitive functionsmust be implemented. Within this framework we hypothesize and detail 7 functional circuitscorresponding to psychological perspectives on the brain: consolidated long-term declarativememory, short-term declarative memory, working memory/information processing, behavioralmemory selection, behavioral memory output, cognitive control, and cortical information flow regulation. Each circuit is described in terms of distinguishable neuronal groups including thecerebral isocortex (9 pyramidal neuronal groups, parahippocampal gyrus and hippocampus,thalamus (4 neuronal groups, basal ganglia (7 neuronal groups, metencephalon, basal forebrainand other subcortical nuclei. We focus on neuroanatomy related to primate non-primary corticalsystems to elucidate the basis underlying the distinct homotypical cognitive architecture. To dis-play the breadth of this review, we introduce a novel method of integrating and presenting datain multiple independent visualizations: an interactive website (www.cognitiveconsilience.comand standalone iPhone and iPad applications. With these tools we present a unique, annotatedview of neuroanatomical consilience (integration of knowledge.

  14. Gyrification from constrained cortical expansion

    CERN Document Server

    Tallinen, Tuomas; Biggins, John S; Mahadevan, L

    2015-01-01

    The exterior of the mammalian brain - the cerebral cortex - has a conserved layered structure whose thickness varies little across species. However, selection pressures over evolutionary time scales have led to cortices that have a large surface area to volume ratio in some organisms, with the result that the brain is strongly convoluted into sulci and gyri. Here we show that the gyrification can arise as a nonlinear consequence of a simple mechanical instability driven by tangential expansion of the gray matter constrained by the white matter. A physical mimic of the process using a layered swelling gel captures the essence of the mechanism, and numerical simulations of the brain treated as a soft solid lead to the formation of cusped sulci and smooth gyri similar to those in the brain. The resulting gyrification patterns are a function of relative cortical expansion and relative thickness (compared with brain size), and are consistent with observations of a wide range of brains, ranging from smooth to highl...

  15. Cerebral hemodynamics and metabolism in patients with moyamoya disease not demonstrating either cerebral infarct or hemorrhage on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, Yasuo; Ichiya, Yuichi; Sasaki, Masayuki; Akashi, Yuko; Yoshida, Tsuyoshi; Fukumura, Toshimitsu; Masuda, Kouji; Matsushima, Toshio; Fukui, Masashi [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1995-12-01

    We evaluated the cerebral hemodynamics and metabolism in moyamoya patients who did not demonstrate either cerebral infarct or hemorrhage on MRI. The subjects consisted of 5 patients with moyamoya disease (4 females and one male, aged from 15 to 40 ears). The CBF, OEF and CMRO{sub 2} of the moyamoya patients did not differ from those of the normal control subjects. The CBV did increase significantly in the cerebral cortices and striatum, but not in the cerebellum. The TT was also significantly prolonged in the frontal and parietal regions. The cerebrovascular CO{sub 2} response was markedly impaired in the frontal, temporal and parietal cortices. However, it was relatively preserved in the occipital cortex, thalamus and cerebellum. Thus, the cerebral hemodynamic reserve capacity decreased even in the moyamoya patients not demonstrating either cerebral infarct or hemorrhage on MRI, and it should be considered in the management of these patients. (author).

  16. Regional vulnerability of longitudinal cortical association connectivity

    Directory of Open Access Journals (Sweden)

    Rafael Ceschin

    2015-01-01

    Full Text Available Preterm born children with spastic diplegia type of cerebral palsy and white matter injury or periventricular leukomalacia (PVL, are known to have motor, visual and cognitive impairments. Most diffusion tensor imaging (DTI studies performed in this group have demonstrated widespread abnormalities using averaged deterministic tractography and voxel-based DTI measurements. Little is known about structural network correlates of white matter topography and reorganization in preterm cerebral palsy, despite the availability of new therapies and the need for brain imaging biomarkers. Here, we combined novel post-processing methodology of probabilistic tractography data in this preterm cohort to improve spatial and regional delineation of longitudinal cortical association tract abnormalities using an along-tract approach, and compared these data to structural DTI cortical network topology analysis. DTI images were acquired on 16 preterm children with cerebral palsy (mean age 5.6 ± 4 and 75 healthy controls (mean age 5.7 ± 3.4. Despite mean tract analysis, Tract-Based Spatial Statistics (TBSS and voxel-based morphometry (VBM demonstrating diffusely reduced fractional anisotropy (FA reduction in all white matter tracts, the along-tract analysis improved the detection of regional tract vulnerability. The along-tract map-structural network topology correlates revealed two associations: (1 reduced regional posterior–anterior gradient in FA of the longitudinal visual cortical association tracts (inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, optic radiation, posterior thalamic radiation correlated with reduced posterior–anterior gradient of intra-regional (nodal efficiency metrics with relative sparing of frontal and temporal regions; and (2 reduced regional FA within frontal–thalamic–striatal white matter pathways (anterior limb/anterior thalamic radiation, superior longitudinal fasciculus and cortical spinal tract

  17. CT findings of early acute cerebral infarction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hoon; Choi, Woo Suk; Ryu, Kyung Nam [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1992-11-15

    The CT findings of the acute cerebral infarction are well known. However the CT findings of early stroke within 24 hours of the onset have not been sufficiently reported. The purpose of this study is to evaluate early acute cerebral infarction on CT within 24 hours after ictus. The early and accurate CT diagnosis could lead to the appropriate therapy and improved outcome of the patients. Authors retrospectively analyzed 16 patients with early acute cerebral infarction. Acute cerebral infarction was confirmed by follow-up CT in 11 patients, SPECT in 4 patients, and MRI in 1 patient. The CT findings of early acute cerebral infarction include effacement of cortical sulci or cistern (n = 16, 100%), hyperattenuation of MCA (n = 3), obscuration of lentiform nucleus (n = 6), loss of insular ribbon (n = 6) and subtle low density in hemisphere (n = 5). The most frequent finding was effacement of cortical sulci in our study, and it was thought to be the most important sign of early acute cerebral infarction.

  18. Cerebral Paragonimiasis.

    Science.gov (United States)

    Miyazaki, I

    1975-01-01

    The first case of cerebral paragonimiasis was reported by Otani in Japan in 1887. This was nine years after Kerbert's discovery of the fluke in the lungs of Bengal tigers and seven years after a human pulmonary infection by the fluke was demonstrated by Baelz and Manson. The first case was a 26-year-old man who had been suffering from cough and hemosputum for one year. The patient developed convulsive seizures with subsequent coma and died. The postmortem examination showed cystic lesions in the right frontal and occipital lobes. An adult fluke was found in the occipital lesion and another was seen in a gross specimen of normal brain tissue around the affected occipital lobe. Two years after Otani's discovery, at autopsy a 29-year-old man with a history of Jacksonian seizure was reported as having cerebral paragonimiasis. Some time later, however, it was confirmed that the case was actually cerebral schistosomiasis japonica. Subsequently, cases of cerebral paragonimiasis were reported. However, the majority of these cases were not confirmed histologically. It was pointed out that some of these early cases were probably not Paragonimus infection. After World War II, reviews as well as case reports were published. Recently, investigations have been reported from Korea, with a clinicla study on 62 cases of cerebral paragonimiasis seen at the Neurology Department of the National Medical Center, Seoul, between 1958 and 1964. In 1971 Higashi described a statistical study on 105 cases of cerebral paragonimiasis that had been treated surgically in Japan.

  19. [Macro- and microscopic systematization of cerebral cortex malformations in children].

    Science.gov (United States)

    Milovanov, A P; Milovanova, O A

    2011-01-01

    For the first time in pediatric pathologicoanatomic practice the complete systematization of cerebral cortex malformations is represented. Organ, macroscopic forms: microencephaly, macroencephaly, micropolygyria, pachygyria, schizencephaly, porencephaly, lissencephaly. Histic microdysgenesis of cortex: type I includes isolated abnormalities such as radial (IA) and tangential (I B) subtypes of cortical dislamination; type II includes sublocal cortical dislamination with immature dysmorphic neurons (II A) and balloon cells (II B); type III are the combination focal cortical dysplasia with tuberous sclerosis of the hippocampus (III A), tumors (III B) and malformations of vessels, traumatic and hypoxic disorders (III C). Band heterotopias. Subependimal nodular heterotopias. Tuberous sclerosis. Cellular typification of cortical dysplasia: immature neurons and balloon cells.

  20. Cortical Blindness in a Child Secondary to Mycoplasma pneumoniae Infection.

    Science.gov (United States)

    Garcia Tirado, A; Jimenez-Rolando, B; Noval, S; Martinez Bermejo, A

    2017-01-01

    Our objective is to present a case of an uncommon complication associated with Mycoplasma pneumoniae infection in a child where cortical blindness was the main clinical feature. Stroke due to an infection by M. pneumoniae is very uncommon. No consensus has been reached on the pathogenesis, although several pathogenic mechanisms have been proposed. Occlusion of posterior cerebral circulation is the most uncommon central nervous system complication of M. pneumoniae infection being reported. Symptoms are usually hemiplegia and dysarthria. We report a case of a 6-year-old boy who suffered cortical blindness due to a stroke 2 days after M. pneumoniae infection. This is the first case of documented cortical blindness due to posterior cerebral arteries occlusion in children after M. pneumoniae infection.

  1. 穴封治疗脑瘫患儿皮质盲18例临床观察%Clinical observation of 18 cerebral palsy combined cortical blindness children used the acupuncture point injection

    Institute of Scientific and Technical Information of China (English)

    翟红印; 许予明; 夏冰

    2014-01-01

    目的:观察穴位注射球后、视区治疗小儿脑瘫皮质盲的效果,寻找治疗小儿皮质盲的治疗方法。方法:采用维生素 B1、B12配置液,穴位为双侧视区、球后,注射后按压3分钟止血,每周治疗三次,十次一个疗程,治疗三个疗程评估。结果:观察18例,痊愈10例,有效1例,其中无效7例,其中9例第一个疗程见效。结论:通过穴位注射治疗皮质盲有确切效果。%Objective:The ef ect of the acupuncture point injection,including retrobulbar injection and visual area injection,and look for treatments to treat child cortical blindness.Methods:Conduct the retrobulbar injection and the visual area injection,using Vitamin B1 Injection and Vitamin B12 Injection,then press to stop bleeding for 5 minutes.Treatment three times a week,ten times as a course,and make an assessment three courses.Result:There were 18 patients,of which ten were cured,one was treated ef ectively,seven were treated inef ectively,and there were 9 patients were treated ef ectively in the first course.Conclusion:The acupuncture point injection can achieve satisfactory ef ect in treatment of child cortical blindness.

  2. Analog and VLSI circuits

    CERN Document Server

    Chen, Wai-Kai

    2009-01-01

    Featuring hundreds of illustrations and references, this book provides the information on analog and VLSI circuits. It focuses on analog integrated circuits, presenting the knowledge on monolithic device models, analog circuit cells, high performance analog circuits, RF communication circuits, and PLL circuits.

  3. Cortico-amygdala-striatal circuits are organized as hierarchical subsystems through the primate amygdala.

    Science.gov (United States)

    Cho, Youngsun T; Ernst, Monique; Fudge, Julie L

    2013-08-28

    The prefrontal and insula cortex, amygdala, and striatum are key regions for emotional processing, yet the amygdala's role as an interface between the cortex and striatum is not well understood. In the nonhuman primate (Macaque fascicularis), we analyzed a collection of bidirectional tracer injections in the amygdala to understand how cortical inputs and striatal outputs are organized to form integrated cortico-amygdala-striatal circuits. Overall, diverse prefrontal and insular cortical regions projected to the basal and accessory basal nuclei of the amygdala. In turn, these amygdala regions projected to widespread striatal domains extending well beyond the classic ventral striatum. Analysis of the cases in aggregate revealed a topographic colocalization of cortical inputs and striatal outputs in the amygdala that was additionally distinguished by cortical cytoarchitecture. Specifically, the degree of cortical laminar differentiation of the cortical inputs predicted amygdalostriatal targets, and distinguished three main cortico-amygdala-striatal circuits. These three circuits were categorized as "primitive," "intermediate," and "developed," respectively, to emphasize the relative phylogenetic and ontogenetic features of the cortical inputs. Within the amygdala, these circuits appeared arranged in a pyramidal-like fashion, with the primitive circuit found in all examined subregions, and subsequent circuits hierarchically layered in discrete amygdala subregions. This arrangement suggests a stepwise integration of the functions of these circuits across amygdala subregions, providing a potential mechanism through which internal emotional states are managed with external social and sensory information toward emotionally informed complex behaviors.

  4. Cerebral Palsy (For Teens)

    Science.gov (United States)

    ... Right Sport for You Healthy School Lunch Planner Cerebral Palsy KidsHealth > For Teens > Cerebral Palsy Print A A ... do just what everyone else does. What Is Cerebral Palsy? Cerebral palsy (CP) is a disorder of the ...

  5. Cortical control of whisker movement.

    Science.gov (United States)

    Petersen, Carl C H

    2014-01-01

    Facial muscles drive whisker movements, which are important for active tactile sensory perception in mice and rats. These whisker muscles are innervated by cholinergic motor neurons located in the lateral facial nucleus. The whisker motor neurons receive synaptic inputs from premotor neurons, which are located within the brain stem, the midbrain, and the neocortex. Complex, distributed neural circuits therefore regulate whisker movement during behavior. This review focuses specifically on cortical whisker motor control. The whisker primary motor cortex (M1) strongly innervates brain stem reticular nuclei containing whisker premotor neurons, which might form a central pattern generator for rhythmic whisker protraction. In a parallel analogous pathway, the whisker primary somatosensory cortex (S1) strongly projects to the brain stem spinal trigeminal interpolaris nucleus, which contains whisker premotor neurons innervating muscles for whisker retraction. These anatomical pathways may play important functional roles, since stimulation of M1 drives exploratory rhythmic whisking, whereas stimulation of S1 drives whisker retraction.

  6. Circuit Connectors

    Science.gov (United States)

    1979-01-01

    The U-shaped wire devices in the upper photo are Digi-Klipsm; aids to compact packaging of electrical and electronic devices. They serve as connectors linking the circuitry of one circuit board with another in multi-board systems. Digi-Klips were originally developed for Goddard Space Flight Center to meet a need for lightweight, reliable connectors to replace hand-wired connections formerly used in spacecraft. They are made of beryllium copper wire, noted for its excellent conductivity and its spring-like properties, which assure solid electrical contact over a long period of time.

  7. Relating neuronal firing patterns to functional differentiation of cerebral cortex.

    Directory of Open Access Journals (Sweden)

    Shigeru Shinomoto

    2009-07-01

    Full Text Available It has been empirically established that the cerebral cortical areas defined by Brodmann one hundred years ago solely on the basis of cellular organization are closely correlated to their function, such as sensation, association, and motion. Cytoarchitectonically distinct cortical areas have different densities and types of neurons. Thus, signaling patterns may also vary among cytoarchitectonically unique cortical areas. To examine how neuronal signaling patterns are related to innate cortical functions, we detected intrinsic features of cortical firing by devising a metric that efficiently isolates non-Poisson irregular characteristics, independent of spike rate fluctuations that are caused extrinsically by ever-changing behavioral conditions. Using the new metric, we analyzed spike trains from over 1,000 neurons in 15 cortical areas sampled by eight independent neurophysiological laboratories. Analysis of firing-pattern dissimilarities across cortical areas revealed a gradient of firing regularity that corresponded closely to the functional category of the cortical area; neuronal spiking patterns are regular in motor areas, random in the visual areas, and bursty in the prefrontal area. Thus, signaling patterns may play an important role in function-specific cerebral cortical computation.

  8. Coordinated scaling of cortical and cerebellar numbers of neurons

    Directory of Open Access Journals (Sweden)

    Suzana Herculano-Houzel

    2010-03-01

    Full Text Available While larger brains possess concertedly larger cerebral cortices and cerebella, the relative size of the cerebral cortex increases with brain size, but relative cerebellar size does not. In the absence of data on numbers of neurons in these structures, this discrepancy has been used to dispute the hypothesis that the cerebral cortex and cerebellum function and have evolved in concert and to support a trend towards neocorticalization in evolution. However, the rationale for interpreting changes in absolute and relative size of the cerebral cortex and cerebellum relies on the assumption that they reflect absolute and relative numbers of neurons in these structures across all species – an assumption that our recent studies have shown to be flawed. Here I show for the first time that the numbers of neurons in the cerebral cortex and cerebellum are directly correlated across 19 mammalian species of 4 different orders, including humans, and increase concertedly in a similar fashion both within and across the orders Eulipotyphla (Insectivora, Rodentia, Scandentia and Primata, such that on average a ratio of 3.6 neurons in the cerebellum to every neuron in the cerebral cortex is maintained across species. This coordinated scaling of cortical and cerebellar numbers of neurons provides direct evidence in favor of concerted function, scaling and evolution of these brain structures, and suggests that the common notion that equates cognitive advancement with neocortical expansion should be revisited to consider in its stead the coordinated scaling of neocortex and cerebellum as a functional ensemble.

  9. 电针对局灶性脑梗死大鼠皮质Slit2/Robo 1表达的影响%Effect of Electroacupuncture of "Neiguan" (PC 6) and "Zusanli" (ST 36) on Expression of Cerebral Cortical Slit 2/Robo 1 in the Focal Cerebral Infarction Rats

    Institute of Scientific and Technical Information of China (English)

    吕凯; 李凤; 龚标; 代恩泽; 汪莹; 曾志华

    2013-01-01

    Objective To observe the effect of electroacupuncture (EA) intervention on expression of Slit 2 and its transmembrane receptor Robo 1 in the cortex tissue of cerebral infarction rats so as to study its mechanism underlying improvement of cerebral ischemia.Methods Ninety male Sprague Dawley rats were randomly divided into control group (n =10),model group (n =40) and EA group (n =40),and the latter two groups were further randomized into four subgroups:1 d,3 d,7 d,and 14 d (n =10 in each subgroup) according to the cerebral ischemia duration.Cerebral infarction model was established by occlusion of the middle cerebral artery (MCAO).EA (80-100 Hz,1-3 mA) was applied to bilateral "Neiguan" (PC 6) and "Zusanli" (ST 36) for 30 min,once daily for 1 d,3 d,7 d,and 14 d,respectively.The animals' neurological defect was assessed using Zea-Longa scoring.The expression of Slit 2 and Robo 1 proteins in the cerebral cortex on the ischemic side was assayed using immunohistochemistry and Western blotting,respectively.Results In comparison with the control group,the neurological score was significantly higher in the model group (P<0.05),and reduced considerably on day 7 and 14 after MCAO in the EA group compared with the model group (P<0.05).Immunohistochemical results showed that in comparison with the control group,the immunoactivity levels of cerebral Slit 2 and Robo 1 were remarkably upregulated on day 1,3 and 7 after MCAO in the model group (P<0.05,P<0.01),and backed to the control levels on day 14 (P>0.05).While compared with the model group,the immunoactivity levels of cerebral Slit 2 and Robo 1 were further obviously upregulated on day 1,3,7 and 14 after cerebral ischemia in the EA group (P<0.05,P<0.01).The results of Western blotting about the expression levels of cerebral Slit 2 and Robo 1 proteins were nearly the same to those of immunohistochemical outcomes in the 4 subgroups apart from that the expression levels of both Slit 2 and Robo 1 proteins were

  10. Ipsilateral Cerebral and Contralateral Cerebellar Hyperperfusion in Patients with Unilateral Cerebral Infarction; SPM Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sun Pyo; Yoon, Joon Kee; Choi, Bong Hoi; Joo, In Soo; Yoon, Seok Nam [Ajou University School of Medicine, Suwon (Korea, Republic of)

    2008-10-15

    Cortical reorganization has an important role in the recovery of stroke. We analyzed the compensatory cerebral and cerebellar perfusion change in patients with unilateral cerebral infarction using statistical parametric mapping (SPM). Fifty seven {sup 99m}Tc-Ethylene Cystein Diethylester (ECD) cerebral perfusion SPECT images of 57 patients (male/female=38/19, mean age=56{+-}17 years) with unilateral cerebral infarction were evaluated retrospectively. Patients were divided into subgroups according to the location (left, right) and the onset (acute, chronic) of infarction. Each subgroup was compared with normal controls (male/female=11/1, mean age =36{+-}10 years) in a voxel-by-voxel manner (two sample t-test, p<0.001) using SPM. All 4 subgroups showed hyperperfusion in the ipsilateral cerebral cortex, but not in the contralateral cerebral cortex. Chronic left and right infarction groups revealed hyperperfusion in the ipsilateral primary sensorimotor cortex, meanwhile, acute subgroups did not. Contralateral cerebellar hyperperfusion was also demonstrated in the chronic left infarction group. Using {sup 99m}Tc-ECD SPECT, we observed ipsilateral cerebral and contralateral cerebeller hyperperfusion in patients with cerebral infarction. However, whether these findings are related to the recovery of cerebral functions should be further evaluated.

  11. 头孢曲松钠对大鼠脑皮质神经元氧糖剥夺损伤的保护作用及其机制%Protective effect and its mechanism of ceftriaxone on injured by rat's cerebral cortical cells oxygenglucose deprivational

    Institute of Scientific and Technical Information of China (English)

    刘春华; 王维治

    2011-01-01

    Objective To explore the protective effect and its mechanism of ceftriaxone(CTX) on cerebral cortical cells of rats injured by oxygen-glucose deprivational (OGD).Methods Cerebral cortical neurocytes of rats were cultured and divided into normal control group, OGD group and CTX pretreatment group.The OGD Models were established in OGD group and CTX pretreatment group.Cytoactive, the expression of glutamate transporter (GLT)-1mRNA, contents of brain-derived neurotrophic factor (BDNF) and interleukin (IL) -6 in the cell culture supernate in each group were assayed.Results Compared with normal control group, neural cytoactive and expression of GLT-1 mRNA were significantly decreased, BDNF and 1 IL-6 were significantly increased in OGD group and CTX pretreatment group( P <0.05 -0.01 ).Compared with OGD group, neural cytoactive, expression of GLT-1 mRNA and BDNF were significantly increase in CTX pretreatment groups (all P <0.01 ), and IL-6 level had no significantly change.Conclusion CTX pretreatment can protect cortical neurocytes from OGD injury by increasing the expression of GLT-1 and BDNF.%目的 研究头孢曲松钠对大鼠脑皮质神经元氧糖剥夺(OGD)损伤的保护作用及其可能的机制.方法 体外培养大鼠脑皮质神经细胞,分为正常对照组、氧糖剥夺(OGD)组和头孢曲松钠(CTX)预处理组.OGD组和CTX预处理组建立OGD模型.并检测各组的细胞活性、细胞谷氨酸转运体-1(GLT-1)mRNA表达、脑源性神经营养因子(BDNF)和白介素(IL)-6含量.结果 与正常对照组比较,OGD组及CTX预处理组神经细胞活性减低,GLT-1 mRNA表达显著下调,细胞培养上清液中BDNF及IL-6含昔显著增加(P<0.05~0.01);与OGD组比较,CTX预处理组神经细胞活性明显增加,GLT-1 mRNA表达上调,细胞培养上清液中BDNF含量增加(均P<0.01),IL-6含量无明显改变.结论 CTX预处理通过上调GLT-1和BDNF表达保护皮质细胞OGD损伤.

  12. LOGIC CIRCUIT

    Science.gov (United States)

    Strong, G.H.; Faught, M.L.

    1963-12-24

    A device for safety rod counting in a nuclear reactor is described. A Wheatstone bridge circuit is adapted to prevent de-energizing the hopper coils of a ball backup system if safety rods, sufficient in total control effect, properly enter the reactor core to effect shut down. A plurality of resistances form one arm of the bridge, each resistance being associated with a particular safety rod and weighted in value according to the control effect of the particular safety rod. Switching means are used to switch each of the resistances in and out of the bridge circuit responsive to the presence of a particular safety rod in its effective position in the reactor core and responsive to the attainment of a predetermined velocity by a particular safety rod enroute to its effective position. The bridge is unbalanced in one direction during normal reactor operation prior to the generation of a scram signal and the switching means and resistances are adapted to unbalance the bridge in the opposite direction if the safety rods produce a predetermined amount of control effect in response to the scram signal. The bridge unbalance reversal is then utilized to prevent the actuation of the ball backup system, or, conversely, a failure of the safety rods to produce the predetermined effect produces no unbalance reversal and the ball backup system is actuated. (AEC)

  13. Effects of prenatal protein malnutrition on the electrical cerebral activity during development.

    Science.gov (United States)

    De Frías, V; Varela, O; Oropeza, J J; Bisiacchi, B; Alvarez, A

    2010-10-04

    Early protein restriction during the prenatal period has significant repercussions on the ontogeny and development of the central nervous system. The present study investigates whether early prenatal protein malnutrition could alter the electrical cerebral activity of the progeny. We used Sprague-Dawley female rats of 200 g randomly divided into three groups: a control group that received a diet with 25% of the protein content (lactalbumin), the experimental group, that received a diet with 6% of the protein content and the rehabilitated group that initially received a diet with 6% of the protein content, then switched to a diet with 25% of the protein content after the weaning period (P20D) up to 60 days of life (P60D). Reduction of the protein content from 25% to 6% of lactalbumin in the diet of pregnant rats produces impairment in the electrical cerebral activity in the progeny at P20D and at P60D. The power spectral analysis for each one of the electroencephalograms revealed that prenatal protein malnutrition in rats produced a significant reduction of the alpha (8-13 Hz) and the beta bands (13-30 Hz) and a significant increase of the theta (4-8 Hz), and delta bands (1-4 Hz), at two different stages of life (P20D and P60D). Similar results were obtained for the rehabilitated group. These results indicate that early malnutrition in life affects the ontogeny of the electrical cerebral activity. This insult probably disrupts the establishment of cortical neural circuits during the critical period of brain development. The rehabilitation period did not revert the impairment in the electrical cerebral activity produced by malnutrition. We used one-way ANOVA analysis, followed by Tukey test (*p<0.001). (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Collective of mechatronics circuit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1987-02-15

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  15. Vasoespasmo cerebral

    OpenAIRE

    1987-01-01

    Vasoespasmo cerebral ocorre em patologias como enxaqueca, hemorragia subaracnóidea, trauma de crânio, após isquemia e/ou hipoxia. A fisiopatologia do vasoespasmo cerebral nestas patologias não está completamente desvendada. Neste artigo são analisados os fatores neuroquímicos e morfológicos responsáveis pelo controle circulatório cerebral. As alterações circulatórias que seguem a hemorragia subaracnóidea são utilizadas como exemplo. Conclui-se que fatores bioquímicos, fisiológicos e morfológi...

  16. Extensive cortical involvement in leptomeningeal carcinomatosis.

    Science.gov (United States)

    Ayzenberg, I; Börnke, C; Tönnes, C; Ziebarth, W; Lavrov, A; Lukas, C

    2012-12-01

    We present a 77-year-old previously well patient with facial asymmetry and progressive weakness of the lower extremities. An initial MRI revealed slight contrast enhancement of the meninges. Three consecutive cerebrospinal fluid examinations demonstrated low glucose concentration, marked elevation of total protein and moderate pleocytosis. No tumor cells, fungi, acid-fast bacilli or mycobacterial DNA were found. The patient's level of consciousness deteriorated dramatically, and follow-up MRI showed widespread extensive cortical hyperintensities. The lesions showed restricted diffusion on diffusion-weighted images as well as low values on the corresponding apparent diffusion coefficient maps, the changes consistent with diffuse cytotoxic edema. Neuropathological examination findings were of leptomeningeal carcinomatosis (LMC) with diffuse continuous infiltration of the cerebral cortex, cerebellum and spinal cord. The autopsy revealed a subcentimetre adenocarcinoma of the lung. To our knowledge, this is the first report demonstrating extensive cortical involvement in adenocarcinomatous LMC.

  17. Cortical mechanisms of mirror therapy after stroke.

    Science.gov (United States)

    Rossiter, Holly E; Borrelli, Mimi R; Borchert, Robin J; Bradbury, David; Ward, Nick S

    2015-06-01

    Mirror therapy is a new form of stroke rehabilitation that uses the mirror reflection of the unaffected hand in place of the affected hand to augment movement training. The mechanism of mirror therapy is not known but is thought to involve changes in cerebral organization. We used magnetoencephalography (MEG) to measure changes in cortical activity during mirror training after stroke. In particular, we examined movement-related changes in the power of cortical oscillations in the beta (15-30 Hz) frequency range, known to be involved in movement. Ten stroke patients with upper limb paresis and 13 healthy controls were recorded using MEG while performing bimanual hand movements in 2 different conditions. In one, subjects looked directly at their affected hand (or dominant hand in controls), and in the other, they looked at a mirror reflection of their unaffected hand in place of their affected hand. The movement-related beta desynchronization was calculated in both primary motor cortices. Movement-related beta desynchronization was symmetrical during bilateral movement and unaltered by the mirror condition in controls. In the patients, movement-related beta desynchronization was generally smaller than in controls, but greater in contralesional compared to ipsilesional motor cortex. This initial asymmetry in movement-related beta desynchronization between hemispheres was made more symmetrical by the presence of the mirror. Mirror therapy could potentially aid stroke rehabilitation by normalizing an asymmetrical pattern of movement-related beta desynchronization in primary motor cortices during bilateral movement. © The Author(s) 2014.

  18. A revised view of sensory cortical parcellation

    Science.gov (United States)

    Wallace, Mark T.; Ramachandran, Ramnarayan; Stein, Barry E.

    2004-01-01

    Traditional cortical parcellation schemes have emphasized the presence of sharply defined visual, auditory, and somatosensory domains populated exclusively by modality-specific neurons (i.e., neurons responsive to sensory stimuli from a single sensory modality). However, the modality-exclusivity of this scheme has recently been challenged. Observations in a variety of species suggest that each of these domains is subject to influences from other senses. Using the cerebral cortex of the rat as a model, the present study systematically examined the capability of individual neurons in visual, auditory, and somatosensory cortex to be activated by stimuli from other senses. Within the major modality-specific domains, the incidence of inappropriate (i.e., nonmatching) and/or multisensory neurons was very low. However, at the borders between each of these domains a concentration of multisensory neurons was found whose modality profile matched the representations in neighboring cortices and that were able to integrate their cross-modal inputs to give rise to enhanced and/or depressed responses. The results of these studies are consistent with some features of both the traditional and challenging views of cortical organization, and they suggest a parcellation scheme in which modality-specific cortical domains are separated from one another by transitional multisensory zones. PMID:14766982

  19. Bilaterally symmetric focal cortical dysplasia in a golden retriever dog.

    Science.gov (United States)

    Casey, K M; Bollen, A W; Winger, K M; Vernau, K M; Dickinson, P J; Higgins, R J; Sisó, S

    2014-11-01

    A 10-year-old golden retriever dog was referred with a 24-h history of generalized seizures. Magnetic resonance imaging of the brain found no abnormalities on 3 mm transverse sections and the dog was subsequently humanely destroyed. Microscopically there was bilaterally symmetrical focal disorganization of cortical grey matter within the tips of the right and left suprasylvian gyri of the temporal cortex. The focal abnormal cortical lamination was characterized by loss of pyramidal neurons with abnormal, irregular, angular, remaining neurons occasionally forming clusters, surrounded by fibrillary astrogliosis and microgliosis and vascular proliferation. These histological findings are consistent with focal cortical dysplasia, a cerebral cortical malformation that causes seizures in people, but not reported previously in the dog.

  20. EphA/ephrin A reverse signaling promotes the migration of cortical interneurons from the medial ganglionic eminence.

    Science.gov (United States)

    Steinecke, André; Gampe, Christin; Zimmer, Geraldine; Rudolph, Judith; Bolz, Jürgen

    2014-01-01

    Inhibitory interneurons control the flow of information and synchronization in the cerebral cortex at the circuit level. During embryonic development, multiple subtypes of cortical interneurons are generated in different regions of the ventral telencephalon, such as the medial and caudal ganglionic eminence (MGE and CGE), as well as the preoptic area (POA). These neurons then migrate over long distances towards their cortical target areas. Diverse families of diffusible and cell-bound signaling molecules, including the Eph/ephrin system, regulate and orchestrate interneuron migration. Ephrin A3 and A5, for instance, are expressed at the borders of the pathway of MGE-derived interneurons and prevent these cells from entering inappropriate regions via EphA4 forward signaling. We found that MGE-derived interneurons, in addition to EphA4, also express ephrin A and B ligands, suggesting Eph/ephrin forward and reverse signaling in the same cell. In vitro and in vivo approaches showed that EphA4-induced reverse signaling in MGE-derived interneurons promotes their migration and that this effect is mediated by ephrin A2 ligands. In EphA4 mutant mice, as well as after ephrin A2 knockdown using in utero electroporation, we found delayed interneuron migration at embryonic stages. Thus, besides functions in guiding MGE-derived interneurons to the cortex through forward signaling, here we describe a novel role of the ephrins in driving these neurons to their target via reverse signaling.

  1. Locus coeruleus stimulation recruits a broad cortical neuronal network and increases cortical perfusion.

    Science.gov (United States)

    Toussay, Xavier; Basu, Kaustuv; Lacoste, Baptiste; Hamel, Edith

    2013-02-20

    The locus coeruleus (LC), the main source of brain noradrenalin (NA), modulates cortical activity, cerebral blood flow (CBF), glucose metabolism, and blood-brain barrier permeability. However, the role of the LC-NA system in the regulation of cortical CBF has remained elusive. This rat study shows that similar proportions (∼20%) of cortical pyramidal cells and GABA interneurons are contacted by LC-NA afferents on their cell soma or proximal dendrites. LC stimulation induced ipsilateral activation (c-Fos upregulation) of pyramidal cells and of a larger proportion (>36%) of interneurons that colocalize parvalbumin, somatostatin, or nitric oxide synthase compared with pyramidal cells expressing cyclooxygenase-2 (22%, p interneurons (16%, p BK, -52%, p < 0.05), and inward-rectifier (Kir, -40%, p < 0.05) K+ channels primarily impaired the hyperemic response. The data demonstrate that LC stimulation recruits a broad network of cortical excitatory and inhibitory neurons resulting in increased cortical activity and that K+ fluxes and EET signaling mediate a large part of the hemodynamic response.

  2. Normal cerebral FDG uptake during childhood

    Energy Technology Data Exchange (ETDEWEB)

    London, Kevin [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Discipline of Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia); Howman-Giles, Robert [The Children' s Hospital at Westmead, Department of Nuclear Medicine, Sydney, NSW (Australia); University of Sydney, Disciplines of Imaging and Paediatrics and Child Health, Sydney Medical School, Sydney, NSW (Australia)

    2014-04-15

    Current understanding of cerebral FDG uptake during childhood originates from a small number of studies in patients with neurological abnormalities. Our aim was to describe cerebral FDG uptake in a dataset of FDG PET scans in children more likely to represent a normal population. We reviewed cerebral FDG PET scans in children up to 16 years of age with suspected/proven extracranial malignancies and the following exclusions: central nervous system metastases, previous malignancies, previous chemotherapy or radiotherapy, development of cerebral metastases during therapy, neurological conditions, taking antiepileptic medication or medications likely to interfere with cerebral metabolism, and general anaesthesia within 24 h. White matter, basal ganglia, thalamus and the cerebellar cortex were analysed using regional SUV{sub max}, and the cerebral cortex, basal ganglia, thalamus and cerebellum were analysed using a regional relative uptake analysis in comparison to maximal cortical uptake. Scans from 30 patients (age range 11 months to 16 years, mean age 10 years 5 months) were included. All regions showed increasing SUV{sub max} with age. The parietal, occipital, lateral temporal and medial temporal lobes showed lower rates of increasing FDG uptake causing changing patterns of regional FDG uptake during childhood. The cortical regions showing the most intense uptake in early childhood were the parietal and occipital lobes. At approximately 7 years of age these regions had relatively less uptake than the frontal lobes and at approximately 10 years of age these regions had relatively less uptake than the thalamus. Relative FDG uptake in the brain has not reached an adult pattern by 1 year of age, but continues to change up to 16 years of age. The changing pattern is due to different regional rates of increasing cortical FDG uptake, which is less rapid in the parietal, occipital and temporal lobes than in the frontal lobes. (orig.)

  3. The cortical hem regulates the size and patterning of neocortex.

    Science.gov (United States)

    Caronia-Brown, Giuliana; Yoshida, Michio; Gulden, Forrest; Assimacopoulos, Stavroula; Grove, Elizabeth A

    2014-07-01

    The cortical hem, a source of Wingless-related (WNT) and bone morphogenetic protein (BMP) signaling in the dorsomedial telencephalon, is the embryonic organizer for the hippocampus. Whether the hem is a major regulator of cortical patterning outside the hippocampus has not been investigated. We examined regional organization across the entire cerebral cortex in mice genetically engineered to lack the hem. Indicating that the hem regulates dorsoventral patterning in the cortical hemisphere, the neocortex, particularly dorsomedial neocortex, was reduced in size in late-stage hem-ablated embryos, whereas cortex ventrolateral to the neocortex expanded dorsally. Unexpectedly, hem ablation also perturbed regional patterning along the rostrocaudal axis of neocortex. Rostral neocortical domains identified by characteristic gene expression were expanded, and caudal domains diminished. A similar shift occurs when fibroblast growth factor (FGF) 8 is increased at the rostral telencephalic organizer, yet the FGF8 source was unchanged in hem-ablated brains. Rather we found that hem WNT or BMP signals, or both, have opposite effects to those of FGF8 in regulating transcription factors that control the size and position of neocortical areas. When the hem is ablated a necessary balance is perturbed, and cerebral cortex is rostralized. Our findings reveal a much broader role for the hem in cortical development than previously recognized, and emphasize that two major signaling centers interact antagonistically to pattern cerebral cortex.

  4. Progesterone increases brain-derived neuroptrophic factor expression and protects against glutamate toxicity in a mitogen-activated protein kinase- and phosphoinositide-3 kinase-dependent manner in cerebral cortical explants.

    Science.gov (United States)

    Kaur, Paramjit; Jodhka, Parmeet K; Underwood, Wendy A; Bowles, Courtney A; de Fiebre, Nancyellen C; de Fiebre, Christopher M; Singh, Meharvan

    2007-08-15

    The higher prevalence and risk for Alzheimer's disease in women relative to men has been partially attributed to the precipitous decline in gonadal hormone levels that occurs in women following the menopause. Although considerable attention has been focused on the consequence of estrogen loss, and thus estrogen's neuroprotective potential, it is important to recognize that the menopause results in a precipitous decline in progesterone levels as well. In fact, progesterone is neuroprotective, although the precise mechanisms involved remain unclear. Based on our previous observation that progesterone elicits the phosphorylation of ERK and Akt, key effectors of the neuroprotective mitogen-activated protein kinase (MAPK) and phosphoinositide-3 kinase (PI3-K) pathways, respectively, we determined whether activation of either of these pathways was necessary for progesterone-induced protection. With organotypic explants (slice culture) of the cerebral cortex, we found that progesterone protected against glutamate-induced toxicity. Furthermore, these protective effects were inhibited by either the MEK1/2 inhibitor UO126 or the PI3-K inhibitor LY294002, supporting the requirement for both the MAPK and PI3-K pathways in progesterone-induced protection. In addition, at a concentration and duration of treatment consistent with our neuroprotection data, progesterone also increased the expression of brain-derived neurotrophic factor (BDNF), at the level of both protein and mRNA. This induction of BDNF may be relevant to the protective effects of progesterone, in that inhibition of Trk signaling, with K252a, inhibited the protective effects of progesterone. Collectively, these data suggest that progesterone is protective via multiple and potentially related mechanisms. (c) 2007 Wiley-Liss, Inc.

  5. Commutation circuit for an HVDC circuit breaker

    Science.gov (United States)

    Premerlani, William J.

    1981-01-01

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

  6. Impaired excitability of somatostatin- and parvalbumin-expressing cortical interneurons in a mouse model of Dravet syndrome.

    Science.gov (United States)

    Tai, Chao; Abe, Yasuyuki; Westenbroek, Ruth E; Scheuer, Todd; Catterall, William A

    2014-07-29

    Haploinsufficiency of the voltage-gated sodium channel NaV1.1 causes Dravet syndrome, an intractable developmental epilepsy syndrome with seizure onset in the first year of life. Specific heterozygous deletion of NaV1.1 in forebrain GABAergic-inhibitory neurons is sufficient to cause all the manifestations of Dravet syndrome in mice, but the physiological roles of specific subtypes of GABAergic interneurons in the cerebral cortex in this disease are unknown. Voltage-clamp studies of dissociated interneurons from cerebral cortex did not detect a significant effect of the Dravet syndrome mutation on sodium currents in cell bodies. However, current-clamp recordings of intact interneurons in layer V of neocortical slices from mice with haploinsufficiency in the gene encoding the NaV1.1 sodium channel, Scn1a, revealed substantial reduction of excitability in fast-spiking, parvalbumin-expressing interneurons and somatostatin-expressing interneurons. The threshold and rheobase for action potential generation were increased, the frequency of action potentials within trains was decreased, and action-potential firing within trains failed more frequently. Furthermore, the deficit in excitability of somatostatin-expressing interneurons caused significant reduction in frequency-dependent disynaptic inhibition between neighboring layer V pyramidal neurons mediated by somatostatin-expressing Martinotti cells, which would lead to substantial disinhibition of the output of cortical circuits. In contrast to these deficits in interneurons, pyramidal cells showed no differences in excitability. These results reveal that the two major subtypes of interneurons in layer V of the neocortex, parvalbumin-expressing and somatostatin-expressing, both have impaired excitability, resulting in disinhibition of the cortical network. These major functional deficits are likely to contribute synergistically to the pathophysiology of Dravet syndrome.

  7. Genetic dissection of GABAergic neural circuits in mouse neocortex

    Directory of Open Access Journals (Sweden)

    Hiroki eTaniguchi

    2014-01-01

    Full Text Available Diverse and flexible cortical functions rely on the ability of neural circuits to perform multiple types of neuronal computations. GABAergic inhibitory interneurons significantly contribute to this task by regulating the balance of activity, synaptic integration, spiking, synchrony, and oscillation in a neural ensemble. GABAergic interneruons display a high degree of cellular diversity in morphology, physiology, connectivity, and gene expression. A considerable number of subtypes of GABAergic interneurons diversify modes of cortical inhibition, enabling various types of information processing in the cortex. Thus, comprehensively understanding fate specification, circuit assembly and physiological function of GABAergic interneurons is a key to elucidate the principles of cortical wiring and function. Recent advances in genetically encoded molecular tools have made a breakthrough to systematically study cortical circuitry at the molecular, cellular, circuit, and whole animal levels. However, the biggest obstacle to fully applying the power of these to analysis of GABAergic circuits was that there were no efficient and reliable methods to express them in subtypes of GABAergic interneurons. Here, I first summarize cortical interneuron diversity and current understanding of mechanisms, by which distinct classes of GABAergic interneurons are generated. I then review recent development in genetically encoded molecular tools for neural circuit research, and genetic targeting of GABAergic interneuron subtypes, particulary focusing on our recent effort to develop and characterize Cre/CreER knockin lines. Finally, I highlight recent success in genetic targeting of chandelier cells (ChCs, the most unique and distinct GABAergic interneuron subtype, and discuss what kind of questions need to be addressed to understand development and function of cortical inhibitory circuits.

  8. Analog circuit design designing dynamic circuit response

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    This second volume, Designing Dynamic Circuit Response builds upon the first volume Designing Amplifier Circuits by extending coverage to include reactances and their time- and frequency-related behavioral consequences.

  9. Research on relation between cortical functional section and acupuncture point

    Science.gov (United States)

    Chen, Shuwang; Li, Chunhua; Liang, Guozhuang; Wang, Shuhai

    2008-02-01

    The application of the infrared imaging using in the brain cognition and the acupuncture is introduced. Acupuncturing a certain point of the healthy experimental cats, observing the responds of the cerebral cortical temperature by using of infrared imaging, and researching the corresponding relation between the acupuncture points with the active sections of the cerebral cortex, so the effect of the acupuncture is obtained. The theory of the refreshment and induce resuscitation pinprick is approved. The method of the "refreshment and induce resuscitation pinprick" can promote the metabolize renovation, improve the living function and increase the healing rate. However, the relations between the points and the cortical functional sections have not the last word still. After removing the skulls on the head, full of the cerebral cortex of a cat are exposed. Observing the infrared imaging and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing the points to judge the activation position. During the process of acupuncture, the trend of the rising temperature on cerebral cortex is primary in terms of the phenomena in the infrared pictures. The cortical hemogram variety is measured in terms of the infrared pictures and the temperature values, so the characteristic curve of the temperature for a corresponding position on the cerebral cortex and the acupuncture point can be obtained. When the acupuncture point is changed, the position where temperature varied on cerebral cortex is different correspondingly. The variety in the cortical functional sections is corresponding to the result of the acupuncture point in terms of the imaging and the temperatures. The experimental results accord with the theoretic model, so they validate the correctness of the "refreshment and induce resuscitation pinprick". According to the experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture

  10. Cortical control of anticipatory postural adjustments prior to stepping.

    Science.gov (United States)

    Varghese, J P; Merino, D M; Beyer, K B; McIlroy, W E

    2016-01-28

    Human bipedal balance control is achieved either reactively or predictively by a distributed network of neural areas within the central nervous system with a potential role for cerebral cortex. While the role of the cortex in reactive balance has been widely explored, only few studies have addressed the cortical activations related to predictive balance control. The present study investigated the cortical activations related to the preparation and execution of anticipatory postural adjustment (APA) that precede a step. This study also examined whether the preparatory cortical activations related to a specific movement is dependent on the context of control (postural component vs. focal component). Ground reaction forces and electroencephalographic (EEG) data were recorded from 14 healthy adults while they performed lateral weight shift and lateral stepping with and without initially preloading their weight to the stance leg. EEG analysis revealed that there were distinct movement-related potentials (MRPs) with concurrent event-related desynchronization (ERD) of mu and beta rhythms prior to the onset of APA and also to the onset of foot-off during lateral stepping in the fronto-central cortical areas. Also, the MRPs and ERD prior to the onset of APA and onset of lateral weight shift were not significantly different suggesting the comparable cortical activations for the generation of postural and focal movements. The present study reveals the occurrence of cortical activation prior to the execution of an APA that precedes a step. Importantly, this cortical activity appears independent of the context of the movement.

  11. Dendritic bundles, minicolumns, columns, and cortical output units

    Directory of Open Access Journals (Sweden)

    Giorgio Innocenti

    2010-03-01

    Full Text Available The search for the fundamental building block of the cerebral cortex has highlighted three structures, perpendicular to the cortical surface: i columns of neurons with radially invariant response properties, e.g., receptive field position, sensory modality, stimulus orientation or direction, frequency tuning etc. ii minicolumns of radially aligned cell bodies and iii bundles, constituted by the apical dendrites of pyramidal neurons with cell bodies in different layers. The latter were described in detail, and sometimes quantitatively, in several species and areas. It was recently suggested that the dendritic bundles consist of apical dendrites belonging to neurons projecting their axons to specific targets. We review the concept above and suggest that another structural and computational unit of cerebral cortex is the cortical output unit (COU, i.e. an assembly of bundles of apical dendrites and their parent cell bodies including each of the outputs to distant cortical or subcortical structures, of a given cortical locus (area or part of an area. This somato-dendritic assembly receives inputs some of which are common to the whole assembly and determine its radially invariant response properties, others are specific to one or more dendritic bundles, and determine the specific response signature of neurons in the different cortical layers and projecting to different targets.

  12. Evolution of cortical neurogenesis.

    Science.gov (United States)

    Abdel-Mannan, Omar; Cheung, Amanda F P; Molnár, Zoltán

    2008-03-18

    The neurons of the mammalian neocortex are organised into six layers. By contrast, the reptilian and avian dorsal cortices only have three layers which are thought to be equivalent to layers I, V and VI of mammals. Increased repertoire of mammalian higher cognitive functions is likely a result of an expanded cortical surface area. The majority of cortical cell proliferation in mammals occurs in the ventricular zone (VZ) and subventricular zone (SVZ), with a small number of scattered divisions outside the germinal zone. Comparative developmental studies suggest that the appearance of SVZ coincides with the laminar expansion of the cortex to six layers, as well as the tangential expansion of the cortical sheet seen within mammals. In spite of great variation and further compartmentalisation in the mitotic compartments, the number of neurons in an arbitrary cortical column appears to be remarkably constant within mammals. The current challenge is to understand how the emergence and elaboration of the SVZ has contributed to increased cortical cell diversity, tangential expansion and gyrus formation of the mammalian neocortex. This review discusses neurogenic processes that are believed to underlie these major changes in cortical dimensions in vertebrates.

  13. Cerebral computed tomography in men with acquired immunodeficiency syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Brun, B.; Boesen, F.; Gerstoft, J.; Nielsen, J.O.; Praestholm, J.

    Cerebral CT scannings were performed in 19 homosexual men with the acquired immunodeficiency syndrome (AIDS). Nearly half of them (9 patients) had cortical atrophy. Three patients with toxoplasmosis had cerebral pathology, in two of them with ring enhancement while the third had an ill-defined nonspecific lesion with slight heterogeneous enhancement without ring formation. Two patients with multifocal leucoencephalopathy and non-Hodgkin's lymphoma, respectively, presented non-enhancing, low attenuating lesions at CT.

  14. Malformations of cortical development and neocortical focus.

    Science.gov (United States)

    Luhmann, Heiko J; Kilb, Werner; Clusmann, Hans

    2014-01-01

    Developmental neocortical malformations resulting from abnormal neurogenesis, disturbances in programmed cell death, or neuronal migration disorders may cause a long-term hyperexcitability. Early generated Cajal-Retzius and subplate neurons play important roles in transient cortical circuits, and structural/functional disorders in early cortical development may induce persistent network disturbances and epileptic disorders. In particular, depolarizing GABAergic responses are important for the regulation of neurodevelopmental events, like neurogenesis or migration, while pathophysiological alterations in chloride homeostasis may cause epileptic activity. Although modern imaging techniques may provide an estimate of the structural lesion, the site and extent of the cortical malformation may not correlate with the epileptogenic zone. The neocortical focus may be surrounded by widespread molecular, structural, and functional disturbances, which are difficult to recognize with imaging technologies. However, modern imaging and electrophysiological techniques enable focused hypotheses of the neocortical epileptogenic zone, thus allowing more specific epilepsy surgery. Focal cortical malformation can be successfully removed with minimal rim, close to or even within eloquent cortex with a promising risk-benefit ratio.

  15. Analog circuit design designing waveform processing circuits

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The fourth volume in the set Designing Waveform-Processing Circuits builds on the previous 3 volumes and presents a variety of analog non-amplifier circuits, including voltage references, current sources, filters, hysteresis switches and oscilloscope trigger and sweep circuitry, function generation, absolute-value circuits, and peak detectors.

  16. Hyperfixation of Tc-99m ECD in subacute cortical infarction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Seung; Kweon, Sun Uck; Ryu, Jin Sook; Moon, Dae Hyuk; Lee, Hee Kyung [College of Medicine, Ulsan Univ., Seoul (Korea, Republic of)

    2001-07-01

    It has been known that hyperfixation of Tc-99m ECD (HF) is not shown in subacute cerebral infarction because the brain distribution of Tc-99m ECD reflects not only perfusion but also the metabolic status of brain tissue. However, we observed several cases with HF in the subacute pure cortical infarction. To find out the cause of HF in subacute cortical infarction. We assessed the difference in associated cerebral hemodynamics and clinical findings between the subacute cortical infarctions with and without HF. We reviewed 16 patients (63.8{+-}8.6 yr, M/F: 15/1) with pure cortical infarction not involving adjacent subcortical white matter on MRI. All patients underwent acetazolamide stress brain perfusion SPECT using Tc-99m ECD and MRI at subacute period (7.3{+-}4.4 days from ictus). Uptake of Tc-99m ECD in infarcted cortex was assessed visually comparing the contralateral side. To assess the difference in associate clinical findings between the infarctions with and without HF, rCVR of the cerebral territory including infarcted cortex, extent of Gd-enhancement on MRI. Intervals between SPECT and ictus, and the presence of associated ICA stenosis were evaluated. Infarctions were focal (n=8) or multifocal (n=8) and located in frontoparietal cortices on MRI. Twelve patients were accompanied with ipsilateral ICA stenosis. Resting SPECT showed increased cortical uptake (=HF) in 7 patients and decreased in 9. rCVR of the MCA territory was preserved in all of the 7 patients with HF, compared with 4 of the 9 patients without HF (p=0.03). Gd-enhancement was minimal in all of the 7 patients with HF, compared with of the 0 patients without HF (p=0.03). Presence of ipsilateral ICA stenosis and intervals from ictus were not different (p>0.1) Subacute cerebral cortical infarction with HF was more frequently associated with preserved rCVR and minimal destruction of the blood-brain barrier than that without HF. Our findings suggest that HF may result from luxury perfusion of

  17. Modulation of Cortical Oscillations by Low-Frequency Direct Cortical Stimulation Is State-Dependent.

    Directory of Open Access Journals (Sweden)

    Sankaraleengam Alagapan

    2016-03-01

    Full Text Available Cortical oscillations play a fundamental role in organizing large-scale functional brain networks. Noninvasive brain stimulation with temporally patterned waveforms such as repetitive transcranial magnetic stimulation (rTMS and transcranial alternating current stimulation (tACS have been proposed to modulate these oscillations. Thus, these stimulation modalities represent promising new approaches for the treatment of psychiatric illnesses in which these oscillations are impaired. However, the mechanism by which periodic brain stimulation alters endogenous oscillation dynamics is debated and appears to depend on brain state. Here, we demonstrate with a static model and a neural oscillator model that recurrent excitation in the thalamo-cortical circuit, together with recruitment of cortico-cortical connections, can explain the enhancement of oscillations by brain stimulation as a function of brain state. We then performed concurrent invasive recording and stimulation of the human cortical surface to elucidate the response of cortical oscillations to periodic stimulation and support the findings from the computational models. We found that (1 stimulation enhanced the targeted oscillation power, (2 this enhancement outlasted stimulation, and (3 the effect of stimulation depended on behavioral state. Together, our results show successful target engagement of oscillations by periodic brain stimulation and highlight the role of nonlinear interaction between endogenous network oscillations and stimulation. These mechanistic insights will contribute to the design of adaptive, more targeted stimulation paradigms.

  18. Spontaneous thrombosis of a giant cerebral varix in a pediatric patient.

    Science.gov (United States)

    Ozturk, Mesut; Aslan, Serdar; Ceyhan Bilgici, Meltem; Idil Soylu, Aysegul; Aydin, Keramettin

    2017-07-20

    Cerebral cortical venous aneurysm also known as cerebral varix is a rare entity that usually occurs in relation to high-flow draining veins of arteriovenous fistulas, arteriovenous malformations, and venous angioma. Isolated cerebral varix is an extremely rare entity. We present a 1-year-old male with isolated cerebral varix. During follow-up, the varix thrombosed spontaneously without causing any neurological deficits. To the best of our knowledge, spontaneous asymptomatic thrombosis of an isolated cerebral varix without any clinical finding was reported for the first time in the literature.

  19. Prediction for human intelligence using morphometric characteristics of cortical surface: partial least square analysis.

    Science.gov (United States)

    Yang, J-J; Yoon, U; Yun, H J; Im, K; Choi, Y Y; Lee, K H; Park, H; Hough, M G; Lee, J-M

    2013-08-29

    A number of imaging studies have reported neuroanatomical correlates of human intelligence with various morphological characteristics of the cerebral cortex. However, it is not yet clear whether these morphological properties of the cerebral cortex account for human intelligence. We assumed that the complex structure of the cerebral cortex could be explained effectively considering cortical thickness, surface area, sulcal depth and absolute mean curvature together. In 78 young healthy adults (age range: 17-27, male/female: 39/39), we used the full-scale intelligence quotient (FSIQ) and the cortical measurements calculated in native space from each subject to determine how much combining various cortical measures explained human intelligence. Since each cortical measure is thought to be not independent but highly inter-related, we applied partial least square (PLS) regression, which is one of the most promising multivariate analysis approaches, to overcome multicollinearity among cortical measures. Our results showed that 30% of FSIQ was explained by the first latent variable extracted from PLS regression analysis. Although it is difficult to relate the first derived latent variable with specific anatomy, we found that cortical thickness measures had a substantial impact on the PLS model supporting the most significant factor accounting for FSIQ. Our results presented here strongly suggest that the new predictor combining different morphometric properties of complex cortical structure is well suited for predicting human intelligence. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Long-Range Cortical Dynamics: A Perspective from the Mouse Sensorimotor Whisker System.

    Science.gov (United States)

    Ni, Jianguang; Chen, Jerry L

    2017-09-16

    In the mammalian neocortex, the capacity to dynamically route and coordinate the exchange of information between areas is a critical feature of cognitive function, enabling processes such as higher-level sensory processing and sensorimotor integration. Despite the importance attributed to long-range connections between cortical areas, their exact operations and role in cortical function remain an open question. In recent years, progress has been made in understanding long-range cortical circuits through work focused on the mouse sensorimotor whisker system. In this review, we examine recent studies dissecting long-range circuits involved in whisker sensorimotor processing as an entry point for understanding the rules that govern long-range cortical circuit function. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Emergence of cortical inhibition by coordinated sensory–driven plasticity at distinct synaptic loci

    OpenAIRE

    Chittajallu, Ramesh; Isaac, John T. R.

    2010-01-01

    Feed–forward GABAergic inhibition sets dendritic integration window thereby controlling timing and output in cortical circuits. However, it is unclear how feed–forward inhibitory circuits emerge, even though this is a critical step for neocortical development and function. Here we show that sensory–experience drives plasticity of the feed–forward inhibitory circuit in mouse layer 4 somatosensory “barrel” cortex in the second postnatal week by two distinct mechanisms. Firstly, sensory–experien...

  2. Immunosuppression by whole-body irradiation and its effect on oedema in experimental cerebral ischaemia

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, R.D.; Kane, P.J.; Mendelow, A.D. (Department of Surgery, Neurosurgery, University of Newcastle-Upon-Tyne (United Kingdom)); Cook, S.; Chambers, I.R.; Clayton, C.B. (Department of Medical Physics, University of Newcastle-Upon-Tyne (United Kingdom))

    1992-01-01

    The effect of global immunosuppression by sublethal whole body X-irradiation on the development of cerebral oedema was assessed 24 h after right middle cerebral artery occulustion in the rat. Irradiation produced a significant leucopaenia and thrombocytopaenia, and significantly reduced cortical oedema when compared to non-irradiated control animals. (au).

  3. Cross-modal synaptic plasticity in adult primary sensory cortices.

    Science.gov (United States)

    Lee, Hey-Kyoung; Whitt, Jessica L

    2015-12-01

    Sensory loss leads to widespread adaptation of brain circuits to allow an organism to navigate its environment with its remaining senses, which is broadly referred to as cross-modal plasticity. Such adaptation can be observed even in the primary sensory cortices, and falls into two distinct categories: recruitment of the deprived sensory cortex for processing the remaining senses, which we term 'cross-modal recruitment', and experience-dependent refinement of the spared sensory cortices referred to as 'compensatory plasticity.' Here we will review recent studies demonstrating that cortical adaptation to sensory loss involves LTP/LTD and homeostatic synaptic plasticity. Cross-modal synaptic plasticity is observed in adults, hence cross-modal sensory deprivation may be an effective way to promote plasticity in adult primary sensory cortices.

  4. Mean field methods for cortical network dynamics

    DEFF Research Database (Denmark)

    Hertz, J.; Lerchner, Alexander; Ahmadi, M.

    2004-01-01

    We review the use of mean field theory for describing the dynamics of dense, randomly connected cortical circuits. For a simple network of excitatory and inhibitory leaky integrate- and-fire neurons, we can show how the firing irregularity, as measured by the Fano factor, increases...... with the strength of the synapses in the network and with the value to which the membrane potential is reset after a spike. Generalizing the model to include conductance-based synapses gives insight into the connection between the firing statistics and the high- conductance state observed experimentally in visual...

  5. Focal cortical dysplasia - review.

    Science.gov (United States)

    Kabat, Joanna; Król, Przemysław

    2012-04-01

    Focal cortical dysplasia is a malformation of cortical development, which is the most common cause of medically refractory epilepsy in the pediatric population and the second/third most common etiology of medically intractable seizures in adults.Both genetic and acquired factors are involved in the pathogenesis of cortical dysplasia. Numerous classifications of the complex structural abnormalities of focal cortical dysplasia have been proposed - from Taylor et al. in 1971 to the last modification of Palmini classification made by Blumcke in 2011. In general, three types of cortical dysplasia are recognized.Type I focal cortical dysplasia with mild symptomatic expression and late onset, is more often seen in adults, with changes present in the temporal lobe.Clinical symptoms are more severe in type II of cortical dysplasia usually seen in children. In this type, more extensive changes occur outside the temporal lobe with predilection for the frontal lobes.New type III is one of the above dysplasias with associated another principal lesion as hippocampal sclerosis, tumor, vascular malformation or acquired pathology during early life.Brain MRI imaging shows abnormalities in the majority of type II dysplasias and in only some of type I cortical dysplasias.THE MOST COMMON FINDINGS ON MRI IMAGING INCLUDE: focal cortical thickening or thinning, areas of focal brain atrophy, blurring of the gray-white junction, increased signal on T2- and FLAIR-weighted images in the gray and subcortical white matter often tapering toward the ventricle. On the basis of the MRI findings, it is possible to differentiate between type I and type II cortical dysplasia. A complete resection of the epileptogenic zone is required for seizure-free life. MRI imaging is very helpful to identify those patients who are likely to benefit from surgical treatment in a group of patients with drug-resistant epilepsy.However, in type I cortical dysplasia, MR imaging is often normal, and also in both types

  6. Employees with Cerebral Palsy

    Science.gov (United States)

    ... Resources Home | Accommodation and Compliance Series: Employees with Cerebral Palsy (CP) By Eddie Whidden, MA Preface Introduction Information ... SOAR) at http://AskJAN.org/soar. Information about Cerebral Palsy (CP) What is CP? Cerebral palsy is a ...

  7. Relating Cortical Wave Dynamics to Learning and Remembering

    Directory of Open Access Journals (Sweden)

    Eduardo Mercado III

    2014-12-01

    Full Text Available Electrical waves propagate across sensory and motor cortices in stereotypical patterns. These waves have been described as potentially facilitating sensory processing when they travel through sensory cortex, as guiding movement preparation and performance when they travel across motor cortex, and as possibly promoting synaptic plasticity and the consolidation of memory traces, especially during sleep. Here, an alternative theoretical framework is suggested that integrates Pavlovian hypotheses about learning and cortical function with concepts from contemporary proceduralist theories of memory. The proposed framework postulates that sensory-evoked cortical waves are gradually modified across repeated experiences such that the waves more effectively differentiate sensory events, and so that the waves are more likely to reverberate. It is argued that the qualities of cortical waves—their origins, form, intensity, speed, periodicity, extent, and trajectories —are a function of both the structural organization of neural circuits and ongoing reverberations resulting from previously experienced events. It is hypothesized that experience-dependent cortical plasticity, both in the short- and long-term, modulates the qualities of cortical waves, thereby enabling individuals to make progressively more precise distinctions between complex sensory events, and to reconstruct components of previously experienced events. Unlike most current neurobiological theories of learning and memory mechanisms, this hypothesis does not assume that synaptic plasticity, or any other form of neural plasticity, serves to store physical records of previously experienced events for later reactivation. Rather, the reorganization of cortical circuits may alter the potential for certain wave patterns to arise and persist. Understanding what factors determine the spatiotemporal dynamics of cortical waves, how structural changes affect their qualities, and how wave dynamics

  8. Cegueira cortical: relato de dois casos clínicos Cortical blindness: report of two cases

    Directory of Open Access Journals (Sweden)

    Raquel de Lima e Silva

    2001-06-01

    Full Text Available O objetivo deste trabalho é relatar dois casos de cegueira cortical atendidos no serviço de urgência da Clínica de Olhos da Santa Casa de Belo Horizonte. A cegueira cortical é uma condição clínica rara e bilateral, de causa isquêmica, caracterizada por lesão no córtex cerebral. Nos presentes casos, o diagnóstico foi feito pela sintomatologia clínica, pelos achados oftalmológicos e pelas alterações obtidas por imagem. Em ambos houve evolução rápida da doença, com perda visual súbita importante. O acompanhamento oftalmológico não revelou melhora significativa da acuidade visual final. A baixa acuidade visual é um sinal importante em oftalmologia e deve ser avaliada com cautela e atenção, visto que pode ser causada pela cegueira cortical, condição rara, grave e ainda pouco estudada no nosso meio.The aim of this work is to report two cases of cortical blindness, evaluated at an ophthalmologic service (Clínica de Olhos da Santa Casa de Belo Horizonte. Cortical blindness is a rare, usually ischemic, bilateral retrogeniculate lesion. The two diagnoses were based on patient complaints, ophthalmologic data and image signs. Both patients suddenly lost their visual function. None presented a significant improvement in their final vision acuity during the evolution. Subnormal visual acuity is an important ophthalmologic sign that must be seen with concern and attention since it may be caused by cortical blindness, a rare and serious condition not yet well studied in our Country.

  9. Severe Cerebral Vasospasm in Patients with Hyperthyroidism

    Science.gov (United States)

    Oh, Hyuk-Jin; Oh, Jae-Sang; Shim, Jai-Joon; Bae, Hack-Gun

    2016-01-01

    Cerebral vasospasm associated with hyperthyroidism has not been reported to cause cerebral infarction. The case reported here is therefore the first of cerebral infarction co-existing with severe vasospasm and hyperthyroidism. A 30-year-old woman was transferred to our hospital in a stuporous state with right hemiparesis. At first, she complained of headache and dizziness. However, she had no neurological deficits or radiological abnormalities. She was diagnosed with hyperthyroidism 2 months ago, but she had discontinued the antithyroid medication herself three days ago. Magnetic resonance imaging and angiography showed cerebral infarction with severe vasospasm. Thus, chemical angioplasty using verapamil was performed two times, and antithyroid medication was administered. Follow-up angiography performed at 6 weeks demonstrated complete recovery of the vasospasm. At the 2-year clinical follow-up, she was alert with mild weakness and cortical blindness. Hyperthyroidism may influence cerebral vascular hemodynamics. Therefore, a sudden increase in the thyroid hormone levels in the clinical setting should be avoided to prevent cerebrovascular accidents. When neurological deterioration is noticed without primary cerebral parenchyma lesions, evaluation of thyroid function may be required before the symptoms occur. PMID:28184350

  10. Severe Cerebral Vasospasm in Patients with Hyperthyroidism.

    Science.gov (United States)

    Oh, Hyuk-Jin; Yoon, Seok-Mann; Oh, Jae-Sang; Shim, Jai-Joon; Bae, Hack-Gun

    2016-12-01

    Cerebral vasospasm associated with hyperthyroidism has not been reported to cause cerebral infarction. The case reported here is therefore the first of cerebral infarction co-existing with severe vasospasm and hyperthyroidism. A 30-year-old woman was transferred to our hospital in a stuporous state with right hemiparesis. At first, she complained of headache and dizziness. However, she had no neurological deficits or radiological abnormalities. She was diagnosed with hyperthyroidism 2 months ago, but she had discontinued the antithyroid medication herself three days ago. Magnetic resonance imaging and angiography showed cerebral infarction with severe vasospasm. Thus, chemical angioplasty using verapamil was performed two times, and antithyroid medication was administered. Follow-up angiography performed at 6 weeks demonstrated complete recovery of the vasospasm. At the 2-year clinical follow-up, she was alert with mild weakness and cortical blindness. Hyperthyroidism may influence cerebral vascular hemodynamics. Therefore, a sudden increase in the thyroid hormone levels in the clinical setting should be avoided to prevent cerebrovascular accidents. When neurological deterioration is noticed without primary cerebral parenchyma lesions, evaluation of thyroid function may be required before the symptoms occur.

  11. Visual experience modulates spatio-temporal dynamics of circuit activation

    Directory of Open Access Journals (Sweden)

    Lang eWang

    2011-06-01

    Full Text Available Persistent reduction in sensory drive in early development results in multiple plastic changes of different cortical synapses. How these experience-dependent modifications affect the spatio-temporal dynamics of signal propagation in neocortical circuits is poorly understood. Here we demonstrate that brief visual deprivation significantly affects the propagation of electrical signals in the primary visual cortex. The spatio-temporal spread of circuit activation upon direct stimulation of its input layer (Layer 4 is reduced, as is the activation of Layer 2/3 – the main recipient of the output from Layer 4. Our data suggest that the decrease in spatio-temporal activation of L2/3 depends on reduced L4 output, and is not intrinsically generated within L2/3. The data shown here suggest that changes in the synaptic components of the visual cortical circuit result not only in alteration of local integration of excitatory and inhibitory inputs, but also in a significant decrease in overall circuit activation. Furthermore, our data indicate a differential effect of visual deprivation on L4 and L2/3, suggesting that while feedforward activation of L2/3 is reduced, its activation by long range, within layer inputs is unaltered. Thus, brief visual deprivation induces experience-dependent circuit re-organization by modulating not only circuit excitability, but also the spatio-temporal patterns of cortical activation within and between layers.

  12. Changes in calcium-binding protein expression in human cortical contusion tissue.

    Science.gov (United States)

    Buriticá, Efraín; Villamil, Liliana; Guzmán, Francisco; Escobar, Martha I; García-Cairasco, Norberto; Pimienta, Hernán J

    2009-12-01

    Traumatic brain injury (TBI) produces several cellular changes, such as gliosis, axonal and dendritic plasticity, and inhibition-excitation imbalance, as well as cell death, which can initiate epileptogenesis. It has been demonstrated that dysfunction of the inhibitory components of the cerebral cortex after injury may cause status epilepticus in experimental models; we proposed to analyze the response of cortical interneurons and astrocytes after TBI in humans. Twelve contusion samples were evaluated, identifying the expression of glial fibrillary acidic protein (GFAP) and calcium-binding proteins (CaBPs). The study was made in sectors with and without preserved cytoarchitecture evaluated with NeuN immunoreactivity (IR). In sectors with total loss of NeuN-IR the results showed a remarkable loss of CaBP-IR both in neuropil and somata. In sectors with conserved cytoarchitecture less drastic changes in CaBP-IR were detected. These changes include a decrease in the amount of parvalbumin (PV-IR) neurons in layer II, an increase of calbindin (CB-IR) neurons in layers III and V, and an increase in calretinin (CR-IR) neurons in layer II. We also observed glial fibrillary acidic protein immunoreactivity (GFAP-IR) in the white matter, in the gray-white matter transition, and around the sectors with NeuN-IR total loss. These findings may reflect dynamic activity as a consequence of the lesion that is associated with changes in the excitatory circuits of neighboring hyperactivated glutamatergic neurons, possibly due to the primary impact, or secondary events such as hypoxia-ischemia. Temporal evolution of these changes may be the substrate linking severe cortical contusion and the resulting epileptogenic activity observed in some patients.

  13. An evolutionary theory of schizophrenia: cortical connectivity, metarepresentation, and the social brain.

    Science.gov (United States)

    Burns, Jonathan Kenneth

    2004-12-01

    Schizophrenia is a worldwide, prevalent disorder with a multifactorial but highly genetic aetiology. A constant prevalence rate in the face of reduced fecundity has caused some to argue that an evolutionary advantage exists in unaffected relatives. Here, I critique this adaptationist approach, and review--and find wanting--Crow's "speciation" hypothesis. In keeping with available biological and psychological evidence, I propose an alternative theory of the origins of this disorder. Schizophrenia is a disorder of the social brain, and it exists as a costly trade-off in the evolution of complex social cognition. Paleoanthropological and comparative primate research suggests that hominids evolved complex cortical interconnectivity (in particular, frontotemporal and frontoparietal circuits) to regulate social cognition and the intellectual demands of group living. I suggest that the ontogenetic mechanism underlying this cerebral adaptation was sequential hypermorphosis and that it rendered the hominid brain vulnerable to genetic and environmental insults. I argue that changes in genes regulating the timing of neurodevelopment occurred prior to the migration of Homo sapiens out of Africa 100,000-150,000 years ago, giving rise to the schizotypal spectrum. While some individuals within this spectrum may have exhibited unusual creativity and iconoclasm, this phenotype was not necessarily adaptive in reproductive terms. However, because the disorder shared a common genetic basis with the evolving circuitry of the social brain, it persisted. Thus schizophrenia emerged as a costly trade-off in the evolution of complex social cognition.

  14. Solid-state circuits

    CERN Document Server

    Pridham, G J

    2013-01-01

    Solid-State Circuits provides an introduction to the theory and practice underlying solid-state circuits, laying particular emphasis on field effect transistors and integrated circuits. Topics range from construction and characteristics of semiconductor devices to rectification and power supplies, low-frequency amplifiers, sine- and square-wave oscillators, and high-frequency effects and circuits. Black-box equivalent circuits of bipolar transistors, physical equivalent circuits of bipolar transistors, and equivalent circuits of field effect transistors are also covered. This volume is divided

  15. Simple Autonomous Chaotic Circuits

    Science.gov (United States)

    Piper, Jessica; Sprott, J.

    2010-03-01

    Over the last several decades, numerous electronic circuits exhibiting chaos have been proposed. Non-autonomous circuits with as few as two components have been developed. However, the operation of such circuits relies on the non-ideal behavior of the devices used, and therefore the circuit equations can be quite complex. In this paper, we present two simple autonomous chaotic circuits using only opamps and linear passive components. The circuits each use one opamp as a comparator, to provide a signum nonlinearity. The chaotic behavior is robust, and independent of nonlinearities in the passive components. Moreover, the circuit equations are among the algebraically simplest chaotic systems yet constructed.

  16. Circuit analysis for dummies

    CERN Document Server

    Santiago, John

    2013-01-01

    Circuits overloaded from electric circuit analysis? Many universities require that students pursuing a degree in electrical or computer engineering take an Electric Circuit Analysis course to determine who will ""make the cut"" and continue in the degree program. Circuit Analysis For Dummies will help these students to better understand electric circuit analysis by presenting the information in an effective and straightforward manner. Circuit Analysis For Dummies gives you clear-cut information about the topics covered in an electric circuit analysis courses to help

  17. Evoked potentials in pediatric cerebral malaria

    Directory of Open Access Journals (Sweden)

    Minal Bhanushali

    2011-12-01

    Full Text Available Cortical evoked potentials (EP provide localized data regarding brain function and may offer prognostic information and insights into the pathologic mechanisms of malariamediated cerebral injury. As part of a prospective cohort study, we obtained somatosensory evoked potentials (SSEPs and brainstem auditory EPs (AEPs within 24 hours of admission on 27 consecutive children admitted with cerebral malaria (CM. Children underwent follow-up for 12 months to determine if they had any long term neurologic sequelae. EPs were obtained in 27 pediatric CM admissions. Two children died. Among survivors followed an average of 514 days, 7/25 (28.0% had at least one adverse neurologic outcome. Only a single subject had absent cortical EPs on admission and this child had a good neurologic outcome. Among pediatric CM survivors, cortical EPs are generally intact and do not predict adverse neurologic outcomes. Further study is needed to determine if alterations in cortical EPs can be used to predict a fatal outcome in CM.

  18. Current limiter circuit system

    Energy Technology Data Exchange (ETDEWEB)

    Witcher, Joseph Brandon; Bredemann, Michael V.

    2017-09-05

    An apparatus comprising a steady state sensing circuit, a switching circuit, and a detection circuit. The steady state sensing circuit is connected to a first, a second and a third node. The first node is connected to a first device, the second node is connected to a second device, and the steady state sensing circuit causes a scaled current to flow at the third node. The scaled current is proportional to a voltage difference between the first and second node. The switching circuit limits an amount of current that flows between the first and second device. The detection circuit is connected to the third node and the switching circuit. The detection circuit monitors the scaled current at the third node and controls the switching circuit to limit the amount of the current that flows between the first and second device when the scaled current is greater than a desired level.

  19. Genetic influences on thinning of the cerebral cortex during development.

    Science.gov (United States)

    van Soelen, I L C; Brouwer, R M; van Baal, G C M; Schnack, H G; Peper, J S; Collins, D L; Evans, A C; Kahn, R S; Boomsma, D I; Hulshoff Pol, H E

    2012-02-15

    During development from childhood to adulthood the human brain undergoes considerable thinning of the cerebral cortex. Whether developmental cortical thinning is influenced by genes and if independent genetic factors influence different parts of the cortex is not known. Magnetic resonance brain imaging was done in twins at age 9 (N = 190) and again at age 12 (N = 125; 113 repeated measures) to assess genetic influences on changes in cortical thinning. We find considerable thinning of the cortex between over this three year interval (on average 0.05 mm; 1.5%), particularly in the frontal poles, and orbitofrontal, paracentral, and occipital cortices. Cortical thinning was highly heritable at age 9 and age 12, and the degree of genetic influence differed for the various areas of the brain. One genetic factor affected left inferior frontal (Broca's area), and left parietal (Wernicke's area) thinning; a second factor influenced left anterior paracentral (sensory-motor) thinning. Two factors influenced cortical thinning in the frontal poles: one of decreasing influence over time, and another independent genetic factor emerging at age 12 in left and right frontal poles. Thus, thinning of the cerebral cortex is heritable in children between the ages 9 and 12. Furthermore, different genetic factors are responsible for variation in cortical thickness at ages 9 and 12, with independent genetic factors acting on cortical thickness across time and between various brain areas during childhood brain development.

  20. Regional patterns of cortical blood flow distinguish extraverts from introverts

    OpenAIRE

    Stenberg, Georg; Risberg, Jarl; Warkentin, S.; Rosén, Ingmar

    1990-01-01

    Eysenck's hypothesis of higher cortical arousal in introverts was examined using regional cerebral blood flow measurement in 37 healthy subjects . The measurement was made at rest, using the133Xe-inhalation method. Estimates of gray matter flow were obtained for 32 brain regions. There was no significant evidence of personality differences in general arousal, as measured by the mean flow level, averaged over all regions. There were, however, regional differences. An overall test of the blood ...

  1. Depression of cortical activity in humans by mild hypercapnia.

    Science.gov (United States)

    Thesen, Thomas; Leontiev, Oleg; Song, Tao; Dehghani, Nima; Hagler, Donald J; Huang, Mingxiong; Buxton, Richard; Halgren, Eric

    2012-03-01

    The effects of neural activity on cerebral hemodynamics underlie human brain imaging with functional magnetic resonance imaging and positron emission tomography. However, the threshold and characteristics of the converse effects, wherein the cerebral hemodynamic and metabolic milieu influence neural activity, remain unclear. We tested whether mild hypercapnia (5% CO2 ) decreases the magnetoencephalogram response to auditory pattern recognition and visual semantic tasks. Hypercapnia induced statistically significant decreases in event-related fields without affecting behavioral performance. Decreases were observed in early sensory components in both auditory and visual modalities as well as later cognitive components related to memory and language. Effects were distributed across cortical regions. Decreases were comparable in evoked versus spontaneous spectral power. Hypercapnia is commonly used with hemodynamic models to calibrate the blood oxygenation level-dependent response. Modifying model assumptions to incorporate the current findings produce a modest but measurable decrease in the estimated cerebral metabolic rate for oxygen change with activation. Because under normal conditions, low cerebral pH would arise when bloodflow is unable to keep pace with neuronal activity, the cortical depression observed here may reflect a homeostatic mechanism by which neuronal activity is adjusted to a level that can be sustained by available bloodflow. Animal studies suggest that these effects may be mediated by pH-modulating presynaptic adenosine receptors. Although the data is not clear, comparable changes in cortical pH to those induced here may occur during sleep apnea, sleep, and exercise. If so, these results suggest that such activities may in turn have generalized depressive effects on cortical activity.

  2. Resting-state cerebellar-cerebral networks are differently affected in first-episode, drug-naive schizophrenia patients and unaffected siblings.

    Science.gov (United States)

    Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Zhang, Zhikun; Yu, Miaoyu; Xiao, Changqing; Zhao, Jingping

    2015-11-26

    Dysconnectivity hypothesis posits that schizophrenia is a disorder with dysconnectivity of the cortico-cerebellar-thalamic-cortical circuit (CCTCC). However, it remains unclear to the changes of the cerebral connectivity with the cerebellum in schizophrenia patients and unaffected siblings. Forty-nine patients with first-episode, drug-naive schizophrenia patients, 46 unaffected siblings of schizophrenia patients and 46 healthy controls participated in the study. Seed-based resting-state functional connectivity approach was employed to analyze the data. Compared with the controls, the patients and the siblings share increased default-mode network (DMN) seed - right Crus II connectivity. The patients have decreased right dorsal attention network (DAN) seed - bilateral cerebellum 4,5 connectivity relative to the controls. By contrast, the siblings exhibit increased FC between the right DAN seed and the right cerebellum 6 and right cerebellum 4,5 compared to the controls. No other abnormal connectivities (executive control network and salience network) are observed in the patients/siblings relative to the controls. There are no correlations between abnormal cerebellar-cerebral connectivities and clinical variables. Cerebellar-cerebral connectivity of brain networks within the cerebellum are differently affected in first-episode, drug-naive schizophrenia patients and unaffected siblings. Increased DMN connectivity with the cerebellum may serve as potential endophenotype for schizophrenia.

  3. Solenoid-Simulation Circuit

    Science.gov (United States)

    Simon, R. A.

    1986-01-01

    Electrical properties of solenoids imitated for tests of control circuits. Simulation circuit imitates voltage and current responses of two engine-controlling solenoids. Used in tests of programs of digital engine-control circuits, also provides electronic interface with circuits imitating electrical properties of pressure sensors and linear variable-differential transformers. Produces voltages, currents, delays, and discrete turnon and turnoff signals representing operation of solenoid in engine-control relay. Many such circuits used simulating overall engine circuitry.

  4. Magnetic Resonance Perfusion Imaging in Malformations of Cortical Development

    Energy Technology Data Exchange (ETDEWEB)

    Widjaja, ED.; Wilkinson, I.D.; Griffiths, P.D. [Academic Section of Radiolog y, Univ. of Sheffield, Sheffield (United Kingdom)

    2007-10-15

    Background: Malformations of cortical development vary in neuronal maturity and level of functioning. Purpose: To characterize regional relative cerebral blood volume (rCBV) and difference in first moment transit time (TTfm) in polymicrogyria and cortical tubers using magnetic resonance (MR) perfusion imaging. Material and Methods: MR imaging and dynamic T2*-weighted MR perfusion imaging were performed in 13 patients with tuberous sclerosis complex, 10 with polymicrogyria, and 18 controls with developmental delay but no macroscopic brain abnormality. Regions of interest were placed in cortical tubers or polymicrogyric cortex and in the contralateral normal-appearing side in patients with malformations. In 'control' subjects, regions of interest were placed in the frontal and parietal lobes in both hemispheres. The rCBV and TTfm of the tuber/contralateral side (rCBVRTSC and TTFMTSC) as well as those of the polymicrogyria/contralateral side (rCBVRPMG and TTFMPMG) were assessed. The right-to-left asymmetry of rCBV and TTfm in the control group was also assessed (rCBVRControls and TTFMControls). Results: There was no significant asymmetry between right and left rCBV or TTfm (P>0.05) in controls. There was significant reduction in rCBVRTSC compared to rCBVRControls (P<0.05), but no significant difference in TTFMTSC compared to TTFMControls (P>0.05). There were no significant differences between rCBVRPMG and rCBVRControls (P>0.05) or TTFMPMG and TTFMControls (P>0.05). Conclusion: Our findings imply that cerebral blood volume of polymicrogyria is similar to normal cortex, but there is reduced cerebral blood volume in cortical tubers. The lower rCBV ratio of cortical tubers may be related to known differences in pathogenetic timing of the underlying abnormalities during brain development or the presence of gliosis.

  5. Cerebral and cerebellar gray matter reduction in first-episode patients with major depressive disorder: A voxel-based morphometry study

    Energy Technology Data Exchange (ETDEWEB)

    Peng Jing, E-mail: ppengjjing@sina.com.cn [Department of Radiology, Xuanwu Hospital of Capital Medical University, No. 45, Chang-Chun St, Xuanwu District, Beijing 100053 (China); Liu Jiangtao, E-mail: Liujiangtao813@sina.com [Department of Radiology, Xuanwu Hospital of Capital Medical University, No. 45, Chang-Chun St, Xuanwu District, Beijing 100053 (China); Nie Binbin, E-mail: niebb@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, PO Box 918, Yu-Quan St, Shijingshan District, Beijing 100049 (China); Li Yang, E-mail: Liyang2007428@hotmail.com [Department of Psychiatry, Anding Hospital of Capital Medical University, No. 5, An Kang Hutong, Deshengmen wai, Xicheng District, Beijing 100088 (China); Shan Baoci, E-mail: shanbc@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, PO Box 918, Yu-Quan St, Shijingshan District, Beijing 100049 (China); Wang Gang, E-mail: gangwang@gmail.com [Department of Psychiatry, Anding Hospital of Capital Medical University, No. 5, An Kang Hutong, Deshengmen wai, Xicheng District, Beijing 100088 (China); Li Kuncheng, E-mail: likuncheng1955@yahoo.com.cn [Department of Radiology, Xuanwu Hospital of Capital Medical University, No. 45, Chang-Chun St, Xuanwu District, Beijing 100053 (China)

    2011-11-15

    Purpose: To investigate cerebral and cerebellar gray matter abnormalities in patients with first-episode major depressive disorder (MDD). Materials and methods: We examined the structural difference in regional gray matter density (GMD) between 22 first-episode MDD patients and 30 age-, gender- and education-matched healthy controls by optimized voxel-based morphometry (VBM) based on magnetic resonance imaging. Results: Compared with healthy controls, MDD patients showed decreased GMD in the right medial and left lateral orbitofrontal cortex, right dorsolateral prefrontal cortex (DLPFC), bilateral temporal pole, right superior temporal gyrus, bilateral anterior insular cortex, left parahippocampal gyrus, and left cerebellum. In addition, in MDD patients, there was a negative correlation between GMD values of the right DLPFC and the score of the depression rating scale. Conclusions: Our findings provided additional support for the involvement of limbic-cortical circuits in the pathophysiology of MDD and preliminary evidence that a defect involving the cerebellum may also be implicated.

  6. [Transient cortical blindness--a complication after coronary angiography--case report].

    Science.gov (United States)

    Borowik, Helena; Kułakowska, Alina; Drozdowski, Wiesław; Dubicki, Artur; Kraśnicki, Paweł

    2008-05-01

    Transient cortical blindness is a very rare complication of cardiovascular and cerebral angiography procedures. We present a case of 63-years-old woman, who developed cortical blindness after coronary angiography. Computed tomography (CT) done immediately after blindness appearance showed bilateral hyperintensive areas (probably due to a leakage of contrast medium) in the occipital and parietal cerebral lobes. All visual symptoms disappeared during 48 hours and CT scan repeated after sight recovery did not show any focal lesions in the brain. A breakdown of the blood-brain barrier with direct contrast neurotoxicity seems to be the causal factor of neurological changes observed in our patient after coronary angiography.

  7. Research on acupuncture points and cortical functional activation position in cats by infrared imaging detection

    Science.gov (United States)

    Chen, Shuwang; Sha, Zhanyou; Wang, Shuhai; Wen, Huanming

    2007-12-01

    The research of the brain cognition is mainly to find out the activation position in brain according to the stimulation at present in the world. The research regards the animals as the experimental objects and explores the stimulation response on the cerebral cortex of acupuncture. It provides a new method, which can detect the activation position on the creatural cerebral cortex directly by middle-far infrared imaging. According to the theory of local temperature situation, the difference of cortical temperature maybe associate with the excitement of cortical nerve cells, the metabolism of local tissue and the local hemal circulation. Direct naked detection of temperature variety on cerebral cortex is applied by middle and far infrared imaging technology. So the activation position is ascertained. The effect of stimulation response is superior to other indirect methods. After removing the skulls on the head, full of cerebral cortex of a cat are exposed. By observing the infrared images and measuring the temperatures of the visual cerebral cortex during the process of acupuncturing, the points are used to judge the activation position. The variety in the cortical functional sections is corresponding to the result of the acupuncture points in terms of infrared images and temperatures. According to experimental results, we know that the variety of a cortical functional section is corresponding to a special acupuncture point exactly.

  8. 18F-AV-1451 PET Imaging in Three Patients with Probable Cerebral Amyloid Angiopathy.

    Science.gov (United States)

    Kim, Hee Jin; Cho, Hanna; Werring, David J; Jang, Young Kyoung; Kim, Yeo Jin; Lee, Jin San; Lee, Juyoun; Jun, Soomin; Park, Seongbeom; Ryu, Young Hoon; Choi, Jae Yong; Cho, Young Seok; Moon, Seung Hwan; Na, Duk L; Lyoo, Chul Hyoung; Seo, Sang Won

    2017-01-01

    Cerebrovascular deposition of amyloid-β, known as cerebral amyloid angiopathy (CAA), is associated with MRI findings of lobar hemorrhage, cerebral microbleeds, and cortical superficial siderosis. Although pathological studies suggest that tau may co-localize with vascular amyloid, this has not yet been investigated in CAA in vivo. Three patients with probable CAA underwent 11C-Pittsburgh Compound B (PiB) PET or 18F-florbetaben PET to evaluate amyloid burden, and 18F-AV-1451 PET to evaluate paired helical filament tau burden. Regions that had cerebral microbleeds or cortical superficial siderosis largely overlapped with those showing increased 18F-AV-1451. Our preliminary study raised the possibility that lobar cerebral microbleeds, and cortical superficial siderosis, which are characteristic markers of vascular amyloid, may be associated with local production of paired helical filament tau.

  9. Visuospatial Functioning in Cerebral Amyloid Angiopathy : A Pilot Study

    NARCIS (Netherlands)

    Valenti, Raffaella; Charidimou, Andreas; Xiong, Li; Boulouis, Gregoire; Fotiadis, Panagiotis; Ayres, Alison; Riley, Grace; Kuijf, Hugo J.|info:eu-repo/dai/nl/341734888; Reijmer, Yael D.; Pantoni, Leonardo; Gurol, M. Edip; Davidsdottir, Sigurros; Greenberg, Steven M.; Viswanathan, Anand

    2017-01-01

    Cerebral amyloid angiopathy (CAA) is a contributor to cognitive impairment in the elderly. We hypothesized that the posterior cortical predilection of CAA would cause visual-processing impairment. We systematically evaluated visuospatial abilities in 22 non-demented CAA patients. Neurocognitive

  10. SOMATOSENSORY EVOKED-POTENTIALS IN CEREBRAL ANEURYSM SURGERY

    NARCIS (Netherlands)

    BUCHTHAL, A; BELOPAVLOVIC, M

    1992-01-01

    Monitoring of median nerve somatosensory evoked potentials (SSEP) during surgery for a basilar artery aneurysm under moderate hypothermia revealed an unexpected loss of the first cortical peak. This was due to compression of the middle cerebral artery under the retractor during the surgical approach

  11. Cerebral perfusion SPECT in transient ischemic attack

    Energy Technology Data Exchange (ETDEWEB)

    You, D.-L. E-mail: dlyou@mail.kfcc.org.tw; Shieh, F.-Y.; Tzen, K.-Y.; Tsai, M.-F.; Kao, P.-F

    2000-04-01

    Purpose: The purpose of our study is to evaluate the efficacy of cerebral perfusion single photon emission computerized tomography (SPECT) in patients with transient ischemic attack (TIA). Methods: Thirty-seven patients with TIA were collected for study. All patients had transient focal neurological symptoms or signs with complete recovery within 24 h after onset. The patients underwent cerebral perfusion SPECT between 6 h and 11 days after onset, with 10 cases performed within 24 h (group A), nine cases performed between 1 and 3 days (group B), 11 cases performed between 3 and 5 days (group C), and seven cases performed after more than 5 days (group D). A semi-quantitative method was used for analyzing the SPECT data, and the difference ratios between lesion side and contralateral normal side were calculated on each pair of regions of interest. Results: In total, 78.4% (29/37) of patients had reduced perfusion in the cerebral cortical regions or deep nuclei, and the regions with reduced perfusion corresponded with clinical presentations of the patients. The abnormal rate with reduced perfusion was 90.0% in group A, 77.8% in group B, 72.7% in group C and 71.4% in group D. Cross cerebellar diaschisis (CCD) was present in seven patients, and all of the primary cerebral perfusion defects of these patients were located at the territory of left or right middle cerebral artery. Conclusion: Cerebral perfusion SPECT is a potential tool to detect cerebral perfusion defects and CCD in patients with TIA. Although the perfusion defect may persist more than 5 days after onset, we suggest cerebral perfusion SPECT should be performed as soon as possible.

  12. Quantitative magnetic resonance imaging of cortical multiple sclerosis pathology

    DEFF Research Database (Denmark)

    Tardif, Christine L; Bedell, Barry J; Eskildsen, Simon Fristed

    2012-01-01

    pathology. The objective of this study was to characterize the MRI signature of CLs to help interpret the changes seen in vivo and elucidate the factors limiting their visualization. A quantitative 3D high-resolution (350 μm isotropic) MRI study at 3 Tesla of a fixed post mortem cerebral hemisphere from......Although significant improvements have been made regarding the visualization and characterization of cortical multiple sclerosis (MS) lesions using magnetic resonance imaging (MRI), cortical lesions (CL) continue to be under-detected in vivo, and we have a limited understanding of the causes of GM...... a patient with MS is presented in combination with matched immunohistochemistry. Type III subpial lesions are characterized by an increase in T1, T2 and M0, and a decrease in MTR in comparison to the normal appearing cortex (NAC). All quantitative MR parameters were associated with cortical GM myelin...

  13. Impact of prenatal environmental stress on cortical development

    Directory of Open Access Journals (Sweden)

    Seiji eIshii

    2015-05-01

    Full Text Available Prenatal exposure of the developing brain to various types of environmental stress increases susceptibility to neuropsychiatric disorders such as autism, attention deficit hyperactivity disorder and schizophrenia. Given that even subtle perturbations by prenatal environmental stress in the cerebral cortex impair the cognitive and memory functions, this review focuses on underlying molecular mechanisms of pathological cortical development. We especially highlight recent works that utilized animal exposure models, human specimens or/and induced Pluripotent Stem (iPS cells to demonstrate: 1. molecular mechanisms shared by various types of environmental stressors, 2. the mechanisms by which the affected extracortical tissues indirectly impact the cortical development and function, and 3. interaction between prenatal environmental stress and the genetic predisposition of neuropsychiatric disorders. Finally, we discuss current challenges for achieving a comprehensive understanding of the role of environmentally disturbed molecular expressions in cortical maldevelopment, knowledge of which may eventually facilitate discovery of interventions for prenatal environment-linked neuropsychiatric disorders.

  14. The continuum of spreading depolarizations in acute cortical lesion development

    DEFF Research Database (Denmark)

    Hartings, Jed A; Shuttleworth, C William; Kirov, Sergei A;

    2017-01-01

    A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum...... of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed....... The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion...

  15. Comparison of gray matter volume and thickness for analysis of cortical changes in Alzheimer's disease

    Science.gov (United States)

    Liu, Jiachao; Li, Ziyi; Chen, Kewei; Yao, Li; Wang, Zhiqun; Li, Kunchen; Guo, Xiaojuan

    2011-03-01

    Gray matter volume and cortical thickness are two indices of concern in brain structure magnetic resonance imaging research. Gray matter volume reflects mixed-measurement information of cerebral cortex, while cortical thickness reflects only the information of distance between inner surface and outer surface of cerebral cortex. Using Scaled Subprofile Modeling based on Principal Component Analysis (SSM_PCA) and Pearson's Correlation Analysis, this study further provided quantitative comparisons and depicted both global relevance and local relevance to comprehensively investigate morphometrical abnormalities in cerebral cortex in Alzheimer's disease (AD). Thirteen patients with AD and thirteen age- and gender-matched healthy controls were included in this study. Results showed that factor scores from the first 8 principal components accounted for ~53.38% of the total variance for gray matter volume, and ~50.18% for cortical thickness. Factor scores from the fifth principal component showed significant correlation. In addition, gray matter voxel-based volume was closely related to cortical thickness alterations in most cortical cortex, especially, in some typical abnormal brain regions such as insula and the parahippocampal gyrus in AD. These findings suggest that these two measurements are effective indices for understanding the neuropathology in AD. Studies using both gray matter volume and cortical thickness can separate the causes of the discrepancy, provide complementary information and carry out a comprehensive description of the morphological changes of brain structure.

  16. Hidden circuits and argumentation

    Science.gov (United States)

    Leinonen, Risto; Kesonen, Mikko H. P.; Hirvonen, Pekka E.

    2016-11-01

    Despite the relevance of DC circuits in everyday life and schools, they have been shown to cause numerous learning difficulties at various school levels. In the course of this article, we present a flexible method for teaching DC circuits at lower secondary level. The method is labelled as hidden circuits, and the essential idea underlying hidden circuits is in hiding the actual wiring of DC circuits, but to make their behaviour evident for pupils. Pupils are expected to find out the wiring of the circuit which should enhance their learning of DC circuits. We present two possible ways to utilise hidden circuits in a classroom. First, they can be used to test and enhance pupils’ conceptual understanding when pupils are expected to find out which one of the offered circuit diagram options corresponds to the actual circuit shown. This method aims to get pupils to evaluate the circuits holistically rather than locally, and as a part of that aim this method highlights any learning difficulties of pupils. Second, hidden circuits can be used to enhance pupils’ argumentation skills with the aid of argumentation sheet that illustrates the main elements of an argument. Based on the findings from our co-operating teachers and our own experiences, hidden circuits offer a flexible and motivating way to supplement teaching of DC circuits.

  17. Circuits Regulating Pleasure and Happiness-Mechanisms of Depression

    NARCIS (Netherlands)

    Loonen, Antonius; Ivanova, Svetlana A

    2016-01-01

    According to our model of the regulation of appetitive-searching vs. distress-avoiding behaviors, the motivation to display these essential conducts is regulated by two parallel cortico-striato-thalamo-cortical, re-entry circuits, including the core and the shell parts of the nucleus accumbens,

  18. Circuits Regulating Pleasure and Happiness-Mechanisms of Depression

    NARCIS (Netherlands)

    Loonen, Antonius; Ivanova, Svetlana A

    2016-01-01

    According to our model of the regulation of appetitive-searching vs. distress-avoiding behaviors, the motivation to display these essential conducts is regulated by two parallel cortico-striato-thalamo-cortical, re-entry circuits, including the core and the shell parts of the nucleus accumbens, resp

  19. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  20. The circuit designer's companion

    CERN Document Server

    Williams, Tim

    2013-01-01

    The Circuit Designer's Companion covers the theoretical aspects and practices in analogue and digital circuit design. Electronic circuit design involves designing a circuit that will fulfill its specified function and designing the same circuit so that every production model of it will fulfill its specified function, and no other undesired and unspecified function.This book is composed of nine chapters and starts with a review of the concept of grounding, wiring, and printed circuits. The subsequent chapters deal with the passive and active components of circuitry design. These topics are foll

  1. A dynamic skull model for simulation of cerebral cortex folding.

    Science.gov (United States)

    Chen, Hanbo; Guo, Lei; Nie, Jingxin; Zhang, Tuo; Hu, Xintao; Liu, Tianming

    2010-01-01

    The mechanisms of human cerebral cortex folding and their interactions during brain development are largely unknown, partly due to the difficulties in biological experiments and data acquisition for the developing fetus brain. Computational modeling and simulation provide a novel approach to the understanding of cortex folding processes in normal or aberrant neurodevelopment. Based on our recently developed computational model of the cerebral cortex folding using neuronal growth model and mechanical skull constraint, this paper presents a computational dynamic model of the brain skull that regulates the cortical folding simulation. Our simulation results show that the dynamic skull model is more biologically realistic and significantly improves our cortical folding simulation results. This work provides further computational support to the hypothesis that skull is an important regulator of cortical folding.

  2. PSD-95 uncoupling from NMDA receptors by Tat-N-dimer ameliorates neuronal depolarisation in cortical spreading depression

    DEFF Research Database (Denmark)

    Kucharz, Krzysztof; Søndergaard Rasmussen, Ida; Bach, Anders;

    2017-01-01

    of the negative shift in direct current potential by 33% (4.1 mV). Furthermore, the compound diminished the average depression of spontaneous electrocorticographic activity by 11% during first 40 min of post-cortical spreading depression recovery, but did not mitigate the suppressing effect of cortical spreading...... during the first hour after i.v. injection. The Tat-N-dimer suppressed stimulation-evoked synaptic activity by 2-20%, while cortical blood flow and cerebral oxygen metabolic (CMRO2) responses were preserved. During cortical spreading depression, the Tat-N-dimer reduced the average amplitude...

  3. Transient cortical blindness as a complication of posterior spinal surgery in a pediatric patient.

    Science.gov (United States)

    Nathan, Senthil T; Jain, Viral; Lykissas, Marios G; Crawford, Alvin H; West, Constance E

    2013-09-01

    Postoperative vision loss after spinal surgery is a well-known but devastating complication that may result from direct ocular ischemia, embolism to the central retinal artery, ischemic optic neuropathy, or occipital cortical ischemia. The occipital cortex is situated in the posterior border zone of the middle and posterior cerebral arteries and is susceptible to ischemic damage. Transient cortical blindness as a cause of postoperative vision loss has never been reported after spine surgery in a child. We report an 11-year-old female patient with muscular dystrophy who underwent posterior spinal fusion and instrumentation under hypotensive anesthesia for scoliosis who developed transient cortical blindness.

  4. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  5. Cortical myoclonus and cerebellar pathology

    NARCIS (Netherlands)

    Tijssen, MAJ; Thom, M; Ellison, DW; Wilkins, P; Barnes, D; Thompson, PD; Brown, P

    2000-01-01

    Objective To study the electrophysiologic and pathologic findings in three patients with cortical myoclonus. In two patients the myoclonic ataxic syndrome was associated with proven celiac disease. Background: The pathologic findings in conditions associated with cortical myoclonus commonly involve

  6. Cortical Abnormalities in ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2003-12-01

    Full Text Available Grey-matter abnormalities at the cortical surface and regional brain size were mapped by high-resolution MRI and surface-based, computational image analytical techniques in a group of 27 children and adolescents with attention deficit hyperactivity disorder (ADHD and 46 controls, matched by age and sex, at the University of California at Los Angeles.

  7. Neuroprotective effects of the immunomodulatory drug Setarud on cerebral ischemia in male rats

    Institute of Scientific and Technical Information of China (English)

    Farzaneh Vafaee; Nasser Zangiabadi; Fatemeh Mehdi Pour; Farzaneh Dehghanian; Majid Asadi-Shekaari; Hossein Karimi Afshar

    2012-01-01

    Anti-inflammatory and anti-oxidant agents can alleviate ischemic cerebral injury. The immunomodulary drug Setarud, which is composed of herbal extracts including Rosa canina, Urtica dioica and Tanacetum vulgare, supplemented with selenium exhibits anti-inflammatory and anti-oxidant properties. Therefore, we hypothesized that Setarud will have a neuroprotective effect against ischemic cerebral injury. To validate this hypothesis, rats were intraperitoneally administered with 0.66 mL/kg Setarud for 30 minutes after middle cerebral artery occlusion. Triphenyltetrazolium chloride staining showed that Setarud could reduce cerebral infarct volume of rats subjected to cerebral ischemia. Transmission electron microscopy and hematoxylin-eosin staining results showed that Setarud could alleviate the degenerative changes in cortical neurons of rats with cerebral ischemia. The inclined plate test and prehensile test showed that Setarud could significantly improve the motor function of rats with cerebral ischemia. These findings suggest that Setarud shows neuroprotective effects against ischemic brain injury.

  8. Circuits on Cylinders

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro; Vinay, V

    2006-01-01

    We consider the computational power of constant width polynomial size cylindrical circuits and nondeterministic branching programs. We show that every function computed by a Pi2 o MOD o AC0 circuit can also be computed by a constant width polynomial size cylindrical nondeterministic branching...... program (or cylindrical circuit) and that every function computed by a constant width polynomial size cylindrical circuit belongs to ACC0....

  9. Electric circuits essentials

    CERN Document Server

    REA, Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Electric Circuits I includes units, notation, resistive circuits, experimental laws, transient circuits, network theorems, techniques of circuit analysis, sinusoidal analysis, polyph

  10. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  11. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  12. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  13. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  14. Short-circuit logic

    NARCIS (Netherlands)

    Bergstra, J.A.; Ponse, A.

    2010-01-01

    Short-circuit evaluation denotes the semantics of propositional connectives in which the second argument is only evaluated if the first argument does not suffice to determine the value of the expression. In programming, short-circuit evaluation is widely used. A short-circuit logic is a variant of p

  15. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

  16. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, Simon Minze; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital converte

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

    Science.gov (United States)

    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

  18. Relationship between higher cortical dysfunction and the findings of magnetic resonance imaging in systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Maeshima, Etsuko; Maeshima, Shinichiro; Yamada, Yoichi; Yukawa, Susumu [Wakayama Medical Coll. (Japan)

    1996-04-01

    The relationship between systemic lupus erythematosus (SLE) and organic lesions was investigated by magnetic resonance imaging (MRI) to clarify the etiology of higher cortical dysfunction in SLE. The subjects were 10 patients with SLE, and higher cortical dysfunction was observed in 8 (80%) of the 10 patients. Five (82.5%) of the 8 patients showed abnormal MRI findings. The findings of higher cortical dysfunction were consistent with the MRI findings in 1 of the 5 patients, but not in the remaining four. MRI revealed no lesion despite the presence of higher cortical dysfunction in three patients. These results suggest that the association of organic changes and functional changes in cerebral nerve cells is important for etiology of higher cortical dysfunction in SLE. (author).

  19. Altered cortical activation from the hand after facial botulinum toxin treatment.

    Science.gov (United States)

    Haenzi, Sara; Stefanics, Gabor; Lanaras, Tatjana; Calcagni, Maurizio; Ghosh, Arko

    2014-01-01

    Plastic interactions between face and hand cortical tactile circuits occur after severe injuries that affect the hand such as in amputation or spinal cord injury. However, whether loss of facial movements alters the cortical circuits involved in processing tactile inputs from the hand remains unknown. In this prospective observational study we used electroencephalography (EEG) to measure cortical activity evoked by tactile stimulation of the hands before and after botulinum toxin-A-induced facial paralysis. We found a reduction in the tactile event-related potentials (ERPs) 6 weeks after the treatment. This suggests that the limited paralysis of facial muscles induced during cosmetic interventions designed to smooth lines and wrinkles on the face is sufficient to alter the cortical processing of tactile inputs from the hand.

  20. Broadcasting of cortical activity to the olfactory bulb.

    Science.gov (United States)

    Boyd, Alison M; Kato, Hiroyuki K; Komiyama, Takaki; Isaacson, Jeffry S

    2015-02-24

    Odor representations are initially formed in the olfactory bulb, which contains a topographic glomerular map of odor molecular features. The bulb transmits sensory information directly to piriform cortex, where it is encoded by distributed ensembles of pyramidal cells without spatial order. Intriguingly, piriform cortex pyramidal cells project back to the bulb, but the information contained in this feedback projection is unknown. Here, we use imaging in awake mice to directly monitor activity in the presynaptic boutons of cortical feedback fibers. We show that the cortex provides the bulb with a rich array of information for any individual odor and that cortical feedback is dependent on brain state. In contrast to the stereotyped, spatial arrangement of olfactory bulb glomeruli, cortical inputs tuned to different odors commingle and indiscriminately target individual glomerular channels. Thus, the cortex modulates early odor representations by broadcasting sensory information diffusely onto spatially ordered bulbar circuits.

  1. Reversible Logic Circuit Synthesis

    CERN Document Server

    Shende, V V; Markov, I L; Prasad, A K; Hayes, John P.; Markov, Igor L.; Prasad, Aditya K.; Shende, Vivek V.

    2002-01-01

    Reversible, or information-lossless, circuits have applications in digital signal processing, communication, computer graphics and cryptography. They are also a fundamental requirement for quantum computation. We investigate the synthesis of reversible circuits that employ a minimum number of gates and contain no redundant input-output line-pairs (temporary storage channels). We propose new constructions for reversible circuits composed of NOT, Controlled-NOT, and TOFFOLI gates (the CNT gate library) based on permutation theory. A new algorithm is given to synthesize optimal reversible circuits using an arbitrary gate library. We also describe much faster heuristic algorithms. We also pursue applications of the proposed techniques to the synthesis of quantum circuits.

  2. Stroke rehabilitation using noninvasive cortical stimulation: hemispatial neglect.

    Science.gov (United States)

    Mylius, Veit; Ayache, Samar S; Zouari, Hela G; Aoun-Sebaïti, Mehdi; Farhat, Wassim H; Lefaucheur, Jean-Pascal

    2012-08-01

    The rehabilitation of neuropsychological sequels of cerebral stroke such as hemispatial neglect by noninvasive cortical stimulation (NICS) attracts increasing attention from the scientific community. The NICS techniques include primarily repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). They are based on the concept of either reactivating a hypoactive cortical region affected by the stroke (the right hemisphere in case of neglect) or reducing cortical hyperactivity of the corresponding cortical region in the contralateral hemisphere (the left hemisphere). In the studies published to date on the topic of neglect rehabilitation, rTMS was used to inhibit the left parietal cortex and tDCS to either activate the right or inhibit the left parietal cortex. Sham-controlled NICS studies assessed short-term effects, whereas long-term effects were only assessed in noncontrolled rTMS studies. Further controlled studies of large series of patients are necessary to determine the best parameters of stimulation (including the optimal cortical target location) according to each subtype of neglect presentation and to the time course of stroke recovery. To date, even if there are serious therapeutic perspectives based on imaging data and experimental studies, the evidence is not compelling enough to recommend any particular NICS protocol to treat this disabling condition in clinical practice.

  3. Specialization of Binaural Responses in Ventral Auditory Cortices

    Science.gov (United States)

    Higgins, Nathan C.; Storace, Douglas A.; Escabí, Monty A.

    2010-01-01

    Accurate orientation to sound under challenging conditions requires auditory cortex, but it is unclear how spatial attributes of the auditory scene are represented at this level. Current organization schemes follow a functional division whereby dorsal and ventral auditory cortices specialize to encode spatial and object features of sound source, respectively. However, few studies have examined spatial cue sensitivities in ventral cortices to support or reject such schemes. Here Fourier optical imaging was used to quantify best frequency responses and corresponding gradient organization in primary (A1), anterior, posterior, ventral (VAF), and suprarhinal (SRAF) auditory fields of the rat. Spike rate sensitivities to binaural interaural level difference (ILD) and average binaural level cues were probed in A1 and two ventral cortices, VAF and SRAF. Continuous distributions of best ILDs and ILD tuning metrics were observed in all cortices, suggesting this horizontal position cue is well covered. VAF and caudal SRAF in the right cerebral hemisphere responded maximally to midline horizontal position cues, whereas A1 and rostral SRAF responded maximally to ILD cues favoring more eccentric positions in the contralateral sound hemifield. SRAF had the highest incidence of binaural facilitation for ILD cues corresponding to midline positions, supporting current theories that auditory cortices have specialized and hierarchical functional organization. PMID:20980610

  4. Dense neuron clustering explains connectivity statistics in cortical microcircuits.

    Directory of Open Access Journals (Sweden)

    Vladimir V Klinshov

    Full Text Available Local cortical circuits appear highly non-random, but the underlying connectivity rule remains elusive. Here, we analyze experimental data observed in layer 5 of rat neocortex and suggest a model for connectivity from which emerge essential observed non-random features of both wiring and weighting. These features include lognormal distributions of synaptic connection strength, anatomical clustering, and strong correlations between clustering and connection strength. Our model predicts that cortical microcircuits contain large groups of densely connected neurons which we call clusters. We show that such a cluster contains about one fifth of all excitatory neurons of a circuit which are very densely connected with stronger than average synapses. We demonstrate that such clustering plays an important role in the network dynamics, namely, it creates bistable neural spiking in small cortical circuits. Furthermore, introducing local clustering in large-scale networks leads to the emergence of various patterns of persistent local activity in an ongoing network activity. Thus, our results may bridge a gap between anatomical structure and persistent activity observed during working memory and other cognitive processes.

  5. Cortical injury in multiple sclerosis; the role of the immune system

    Directory of Open Access Journals (Sweden)

    Walker Caroline A

    2011-12-01

    Full Text Available Abstract The easily identifiable, ubiquitous demyelination and neuronal damage that occurs within the cerebral white matter of patients with multiple sclerosis (MS has been the subject of extensive study. Accordingly, MS has historically been described as a disease of the white matter. Recently, the cerebral cortex (gray matter of patients with MS has been recognized as an additional and major site of disease pathogenesis. This acknowledgement of cortical tissue damage is due, in part, to more powerful MRI that allows detection of such injury and to focused neuropathology-based investigations. Cortical tissue damage has been associated with inflammation that is less pronounced to that which is associated with damage in the white matter. There is, however, emerging evidence that suggests cortical damage can be closely associated with robust inflammation not only in the parenchyma, but also in the neighboring meninges. This manuscript will highlight the current knowledge of inflammation associated with cortical tissue injury. Historical literature along with contemporary work that focuses on both the absence and presence of inflammation in the cerebral cortex and in the cerebral meninges will be reviewed.

  6. A Developmental and Genetic Classification for Malformations of Cortical Development: Update 2012

    Science.gov (United States)

    Barkovich, A. James; Guerrini, Renzo; Kuzniecky, Ruben I.; Jackson, Graeme D.; Dobyns, William B.

    2012-01-01

    Malformations of cerebral cortical development include a wide range of developmental disorders that are common causes of neurodevelopmental delay and epilepsy. In addition, study of these disorders contributes greatly to the understanding of normal brain development and its perturbations. The rapid recent evolution of molecular biology, genetics…

  7. Exact Threshold Circuits

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2010-01-01

    We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave with the ......We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave...... with the well-studied corresponding hierarchies defined using ordinary threshold gates. A major open problem in Boolean circuit complexity is to provide an explicit super-polynomial lower bound for depth two threshold circuits. We identify the class of depth two exact threshold circuits as a natural subclass...

  8. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  9. Purely Cortical Anaplastic Ependymoma

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    Flávio Ramalho Romero

    2012-01-01

    Full Text Available Ependymomas are glial tumors derived from ependymal cells lining the ventricles and the central canal of the spinal cord. It may occur outside the ventricular structures, representing the extraventicular form, or without any relationship of ventricular system, called ectopic ependymona. Less than fifteen cases of ectopic ependymomas were reported and less than five were anaplastic. We report a rare case of pure cortical ectopic anaplastic ependymoma.

  10. Intra-areal and corticocortical circuits arising in the dysgranular zone of rat primary somatosensory cortex that processes deep somatic input.

    Science.gov (United States)

    Kim, Uhnoh; Lee, Taehee

    2013-08-01

    Somesthesis-guided exploration of the external world requires cortical processing of both cutaneous and proprioceptive information and their integration into motor commands to guide further haptic movement. In the past, attention has been given mostly to the cortical circuits processing cutaneous information for somatic motor integration. By comparison, little has been examined about how cortical circuits are organized for higher order proprioceptive processing. Using the rat cortex as a model, we characterized the intrinsic and corticocortical circuits arising in the major proprioceptive region of the primary somatosensory cortex (SI) that is conventionally referred to as the dysgranular zone (DSZ). We made small injections of biotinylated dextran amine (BDA) as an anterograde tracer in various parts of the DSZ, revealing three distinct principles of its cortical circuit organization. First, its intrinsic circuits extend mainly along the major axis of DSZ to organize multiple patches of interconnections. Second, the central and peripheral regions of DSZ produce differential patterns of intra-areal and corticocortical circuits. Third, the projection fields of DSZ encompass only selective regions of the second somatic (SII), posterior parietal (PPC), and primary motor (MI) cortices. These projection fields are at least partially separated from those of SI cutaneous areas. We hypothesize, based on these observations, that the cortical circuits of DSZ facilitate a modular integration of proprioceptive information along its major axis and disseminate this information to only selective parts of higher order somatic and MI cortices in parallel with cutaneous information.

  11. A Computational Growth Model for Measuring Dynamic Cortical Development in the First Year of Life

    Science.gov (United States)

    Nie, Jingxin; Li, Gang; Wang, Li; Gilmore, John H.; Lin, Weili

    2012-01-01

    Human cerebral cortex develops extremely fast in the first year of life. Quantitative measurement of cortical development during this early stage plays an important role in revealing the relationship between cortical structural and high-level functional development. This paper presents a computational growth model to simulate the dynamic development of the cerebral cortex from birth to 1 year old by modeling the cerebral cortex as a deformable elastoplasticity surface driven via a growth model. To achieve a high accuracy, a guidance model is also incorporated to estimate the growth parameters and cortical shapes at later developmental stages. The proposed growth model has been applied to 10 healthy subjects with longitudinal brain MR images acquired at every 3 months from birth to 1 year old. The experimental results show that our proposed method can capture the dynamic developmental process of the cortex, with the average surface distance error smaller than 0.6 mm compared with the ground truth surfaces, and the results also show that 1) the curvedness and sharpness decrease from 2 weeks to 12 months and 2) the frontal lobe shows rapidly increasing cortical folding during this period, with relatively slower increase of the cortical folding in the occipital and parietal lobes. PMID:22047969

  12. Corticostriatal circuit mechanisms of value-based action selection: Implementation of reinforcement learning algorithms and beyond.

    Science.gov (United States)

    Morita, Kenji; Jitsev, Jenia; Morrison, Abigail

    2016-09-15

    Value-based action selection has been suggested to be realized in the corticostriatal local circuits through competition among neural populations. In this article, we review theoretical and experimental studies that have constructed and verified this notion, and provide new perspectives on how the local-circuit selection mechanisms implement reinforcement learning (RL) algorithms and computations beyond them. The striatal neurons are mostly inhibitory, and lateral inhibition among them has been classically proposed to realize "Winner-Take-All (WTA)" selection of the maximum-valued action (i.e., 'max' operation). Although this view has been challenged by the revealed weakness, sparseness, and asymmetry of lateral inhibition, which suggest more complex dynamics, WTA-like competition could still occur on short time scales. Unlike the striatal circuit, the cortical circuit contains recurrent excitation, which may enable retention or temporal integration of information and probabilistic "soft-max" selection. The striatal "max" circuit and the cortical "soft-max" circuit might co-implement an RL algorithm called Q-learning; the cortical circuit might also similarly serve for other algorithms such as SARSA. In these implementations, the cortical circuit presumably sustains activity representing the executed action, which negatively impacts dopamine neurons so that they can calculate reward-prediction-error. Regarding the suggested more complex dynamics of striatal, as well as cortical, circuits on long time scales, which could be viewed as a sequence of short WTA fragments, computational roles remain open: such a sequence might represent (1) sequential state-action-state transitions, constituting replay or simulation of the internal model, (2) a single state/action by the whole trajectory, or (3) probabilistic sampling of state/action.

  13. Therapeutic potential of the novel hybrid molecule JM-20 against focal cortical ischemia in rats

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    Yanier Núñez Figueredo

    2016-08-01

    Full Text Available Context: Despite the great mortality and morbidity of stroke, treatment options remain limited. We previously showed that JM-20, a novel synthetic molecule, possessed a strong neuroprotective effect in rats subjected to transient middle cerebral artery occlusion. However, to verify the robustness of the pre-clinical neuroprotective effects of JM-20 to get good prognosis in the translation to the clinic, it is necessary to use other experimental models of brain ischemia. Aims: To evaluate the neuroprotective effects of JM-20 following the onset of permanent focal cerebral ischemia induced in rats by thermocoagulation of blood into pial blood vessels of cerebral cortices. Methods: Ischemic lesion was induced by thermocoagulation of blood into pial blood vessels of primary motor and somatosensory cortices. Behavioral performance was evaluated by the cylinder testing for a period of 2, 3 and 7 days after surgery, and was followed by histopathological study in brain cortex stained with hematoxylin- eosin. Results: Ischemic injury resulted in impaired function of the forelimb evidenced by high asymmetry punctuation, and caused histopathological alterations indicative of tissue damage at cerebral cortex. JM-20 treatment (4 and 8 mg/kg significantly decreased asymmetry scores and histological alterations with a marked preservation of cortical neurons. Conclusions: The effects of permanent brain ischemia were strongly attenuated by JM-20 administration, which expands and improves the current preclinical data of JM-20 as neuroprotector against cerebral ischemia, and strongly support the examination of its translation to the clinic to treat acute ischemic stroke.

  14. Cortical cartography reveals political and physical maps.

    Science.gov (United States)

    Loring, David W; Gaillard, William Davis; Bookheimer, Susan Y; Meador, Kimford J; Ojemann, Jeffrey G

    2014-05-01

    Advances in functional imaging have provided noninvasive techniques to probe brain organization of multiple constructs including language and memory. Because of high overall rates of agreements with older techniques, including Wada testing and cortical stimulation mapping (CSM), some have proposed that those approaches should be largely abandoned because of their invasiveness, and replaced with noninvasive functional imaging methods. High overall agreement, however, is based largely on concordant language lateralization in series dominated by cases of typical cerebral dominance. Advocating a universal switch from Wada testing and cortical stimulation mapping to functional magnetic resonance imaging (fMRI) or magnetoencephalography (MEG) ignores the differences in specific expertise across epilepsy centers, many of which often have greater skill with one approach rather than the other, and that Wada, CSM, fMRI, and MEG protocols vary across institutions resulting in different outcomes and reliability. Specific patient characteristics also affect whether Wada or CSM might influence surgical management, making it difficult to accept broad recommendations against currently useful clinical tools. Although the development of noninvasive techniques has diminished the frequency of more invasive approaches, advocating their use to replace Wada testing and CSM across all epilepsy surgery programs without consideration of the different skills, protocols, and expertise at any given center site is ill-advised. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  15. Isolation of locally derived stem/progenitor cells from the peri-infarct area that do not migrate from the lateral ventricle after cortical stroke.

    Science.gov (United States)

    Shimada, Issei S; Peterson, Brittni M; Spees, Jeffrey L

    2010-09-01

    Neurogenesis can arise from neural stem/progenitor cells of the subventricular zone after strokes involving both the cortex and striatum. However, it is controversial whether all types of stroke and strokes of different sizes activate neurogenesis from the subventricular zone niche. In contrast with cortical/striatal strokes, repair and remodeling after mild cortical strokes may involve to a greater extent local cortical stem/progenitor cells and cells from nonneurogenic niches. We compared stem/progenitor cell responses after focal cortical strokes produced by distal middle cerebral artery occlusion and cortical/striatal strokes produced by the intraluminal suture model. To label migrating neuroblasts from the subventricular zone, we injected DiI to the lateral ventricle after distal middle cerebral artery occlusion. By immunohistochemistry, we characterized cells expressing stem/progenitor cell markers in the peri-infarct area. We isolated cortical stem/progenitor cells from the peri-infarct area after distal middle cerebral artery occlusion and assayed their self-renewal and differentiation capacity. In contrast with cortical/striatal strokes, focal cortical strokes did not induce neuroblast migration from the subventricular zone to the infarct zone after distal middle cerebral artery occlusion. By immunohistochemistry, we observed subpopulations of reactive astrocytes in the peri-infarct area that coexpressed radial glial cell markers such as Sox2, Nestin, and RC2. Clonal neural spheres isolated from the peri-infarct area after distal middle cerebral artery occlusion differentiated into neurons, astrocytes, oligodendrocytes, and smooth muscle cells. Notably, neural spheres isolated from the peri-infarct area also expressed RC2 before differentiation. Mild cortical strokes that do not penetrate the striatum activate local cortical stem/progenitor cells but do not induce neuroblast migration from the subventricular zone niche.

  16. The long and the short of it: Gene and environment interactions during early cortical development and consequences for long-term neurological disease

    Directory of Open Access Journals (Sweden)

    Helen eStolp

    2012-06-01

    Full Text Available Cortical development is a complex amalgamation of proliferation, migration, differentiation and circuit formation. These processes follow defined timescales and are controlled by a combination of intrinsic and extrinsic factors. It is currently unclear how robust and flexible these processes are and whether the developing brain has the capacity to recover from disruptions to normal cortical development. What is clear is that there are a number of cognitive disorders or conditions that are elicited as a result of disrupted cortical development, although it may take a long time for the full pathophysiology of the conditions to be realised clinically. The critical window for the manifestation of a neurodevelopmental disorder is prolonged, and there is the potential for a complex interplay between genes and environment. While there have been extended investigations into the genetic basis of a number of neurological disorders, limited definitive associations have been discovered. Many environmental factors, including inflammation and stress, have been linked to neurodevelopmental disorders, and it may be that a better understanding of the interplay between genes and environment will speed progress in this field. In particular, the development of the brain needs to be considered in the context of the whole materno-foetal unit as the degree of the metabolic, endocrine or inflammatory responses, for example, will greatly influence the environment in which the brain develops. This review will emphasize the importance of extending neurodevelopmental studies to the contribution of the placenta, vasculature, cerebrospinal fluid, and to maternal and foetal immune response. These combined investigations are more likely to reveal genetic and environmental factors that influence the different stages of neuronal development and potentially lead to the better understanding of the aetiology of neurological disorders such as autism, epilepsy, cerebral palsy and

  17. Identifying and characterising cerebral visual impairment in children: a review.

    Science.gov (United States)

    Philip, Swetha Sara; Dutton, Gordon N

    2014-05-01

    Cerebral visual impairment (CVI) comprises visual malfunction due to retro-chiasmal visual and visual association pathway pathology. This can be isolated or accompany anterior visual pathway dysfunction. It is a major cause of low vision in children in the developed and developing world due to increasing survival in paediatric and neonatal care. CVI can present in many combinations and degrees. There are multiple causes and it is common in children with cerebral palsy. CVI can be identified easily, if a structured approach to history-taking is employed. This review describes the features of CVI and describes practical management strategies aimed at helping affected children. A literature review was undertaken using 'Medline' and 'Pubmed'. Search terms included cerebral visual impairment, cortical visual impairment, dorsal stream dysfunction and visual function in cerebral palsy.

  18. Cortical projections to the human red nucleus: a diffusion tensor tractography study with a 1.5-T MRI machine

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    Habas, Christophe; Cabanis, Emmanuel Alain [Universite Pierre et Marie Curie Paris 6, Service de Neuroimagerie, Centre Hospitalier National d' Optalmologie des Quinze-Vingts, Paris (France)

    2006-10-15

    Previous studies in apes and monkeys have shown that the red nucleus receives projections from the sensorimotor and premotor cortices, whereas other experiments carried out with injured human brains have found corticorubral projections issuing from associative areas. Therefore, we reassessed in vivo the human anatomical projections from the cerebral cortex to the red nucleus using diffusion tensor imaging (DTI) axonal tracking. The connectivity between the cerebral cortex and the red nuclei of seven volunteers was studied at 1.5 T using streamlined DTI axonal tracking. Trajectories were constantly tracked between the red nuclei and the ipsilateral pericentral and prefrontal cortices, as well as the temporal cortex and the striatum in two subjects. Within the cerebral trunk, trajectories also include the superior cerebellar peduncle and the central tegmental tract. The human red nucleus receives its main afferences from the sensorimotor and prefrontal cortices. (orig.)

  19. Cortical potentials associated with voluntary mandibular movements.

    Science.gov (United States)

    Yoshida, K; Kaji, R; Hamano, T; Kohara, N; Kimura, J; Shibasaki, H; Iizuka, T

    2000-07-01

    Movement-related cortical potentials (MRCPs) are negative potentials over the scalp, which gradually increase prior to voluntary movements, and might be applied to elucidate the cortical efferent function of the mandibular movements. We compared the MRCPs accompanying various mandibular movements to study the motor control mechanism underlying these movements. Electroencephalograms (EEGs) were recorded from 11 electrodes placed over the scalp (F3, Fz, F4, T3, C3, Cz, C4, T4, P3, Pz, and P4), according to the International 10-20 System, and electromyograms (EMGs) were obtained from surface electrodes over the masseter muscle and the anterior belly of the digastric muscle. Ten healthy subjects were requested to make brisk and self-paced mandibular movements in 4 different directions (mouth-opening and -closing, and left and right lateral movements). We obtained MRCPs by averaging the EEG, using the visually determined EMG onset as a trigger signal. In all the movements, a slowly increasing, bilaterally widespread negativity starting 1.5 to 2.0 sec before the EMG onset (Bereitschaftspotential, or BP proper) was observed, with the maximum over the vertex region. The negative slope (NS') occurred about 300 to 700 msec before the EMG onset. The cortical maps of BP/NS' (BP and NS' combined), immediately prior to the mouth-opening and closing, showed a symmetrical distribution, whereas that for the lateral movements showed a tendency of predominance over the hemisphere ipsilateral to the direction of the movement. BP/NS' amplitudes at the onset of movement differed significantly or tended to do so between open, close, and lateral movements, suggesting that MRCP recordings may thus provide a means to explore the role of the cerebral cortex in the control of mandibular movements.

  20. Lateral hypothalamic circuits for feeding and reward.

    Science.gov (United States)

    Stuber, Garret D; Wise, Roy A

    2016-02-01

    In experiments conducted over 60 years ago, the lateral hypothalamic area (LHA) was identified as a critical neuroanatomical substrate for motivated behavior. Electrical stimulation of the LHA induces voracious feeding even in well-fed animals. In the absence of food, animals will work tirelessly, often lever-pressing thousands of times per hour, for electrical stimulation at the same site that provokes feeding, drinking and other species-typical motivated behaviors. Here we review the classic findings from electrical stimulation studies and integrate them with more recent work that has used contemporary circuit-based approaches to study the LHA. We identify specific anatomically and molecularly defined LHA elements that integrate diverse information arising from cortical, extended amygdala and basal forebrain networks to ultimately generate a highly specified and invigorated behavioral state conveyed via LHA projections to downstream reward and feeding-specific circuits.

  1. United Cerebral Palsy

    Science.gov (United States)

    ... be sure to follow us on Twitter . United Cerebral Palsy UCP educates, advocates and provides support services to ... Partners Merz Logo Sprint Relay Copyright © 2015 United Cerebral Palsy 1825 K Street NW Suite 600 Washington, DC ...

  2. Employees with Cerebral Palsy

    Science.gov (United States)

    ... problems in the muscles or nerves. Instead, faulty development or damage to motor areas in the brain disrupt the brain's ability to adequately control movement and posture (United Cerebral Palsy, 2010). "Cerebral" refers to the ...

  3. Foreign gene expression in an organotypic culture of cortical anlage after in vivo electroporation.

    Science.gov (United States)

    Miyasaka, N; Arimatsu, Y; Takiguchihayashi, K

    1999-08-01

    A high level of foreign gene expression in organotypic cultures of the cerebral cortical anlage was achieved by electroporation-mediated gene transfer in vivo. A mammalian expression plasmid for green fluorescent protein (GFP) gene was injected into the lateral ventricle of rat embryos. Immediately after the plasmid DNA injection, the head of the embryo was electroporated between a pair of tweezer-type electrodes. The cortical anlage was isolated and maintained organotypically up to 21 days in vitro (DIV). The GFP-transgene was expressed intensely in neural progenitor cells at 1 DIV. GFP-expressing cells were still detectable and were demonstrated to differentiate into neurons and glia at 21 DIV. This system is expected to be useful for molecular analysis of cerebral cortical development and function.

  4. Brain and art: illustrations of the cerebral convolutions. A review.

    Science.gov (United States)

    Lazić, D; Marinković, S; Tomić, I; Mitrović, D; Starčević, A; Milić, I; Grujičić, M; Marković, B

    2014-08-01

    Aesthetics and functional significance of the cerebral cortical relief gave us the idea to find out how often the convolutions are presented in fine art, and in which techniques, conceptual meaning and pathophysiological aspect. We examined 27,614 art works created by 2,856 authors and presented in art literature, and in Google images search. The cerebral gyri were shown in 0.85% of the art works created by 2.35% of the authors. The concept of the brain was first mentioned in ancient Egypt some 3,700 years ago. The first artistic drawing of the convolutions was made by Leonardo da Vinci, and the first colour picture by an unknown Italian author. Rembrandt van Rijn was the first to paint the gyri. Dozens of modern authors, who are professional artists, medical experts or designers, presented the cerebralc onvolutions in drawings, paintings, digital works or sculptures, with various aesthetic, symbolic and metaphorical connotation. Some artistic compositions and natural forms show a gyral pattern. The convolutions, whose cortical layers enable the cognitive functions, can be affected by various disorders. Some artists suffered from those disorders, and some others presented them in their artworks. The cerebral convolutions or gyri, thanks to their extensive cortical mantle, are the specific morphological basis for the human mind, but also the structures with their own aesthetics. Contemporary authors relatively often depictor model the cerebral convolutions, either from the aesthetic or conceptual aspect. In this way, they make a connection between the neuroscience and fineart.

  5. 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

  6. Spine pruning drives antipsychotic-sensitive locomotion via circuit control of striatal dopamine.

    Science.gov (United States)

    Kim, Il Hwan; Rossi, Mark A; Aryal, Dipendra K; Racz, Bence; Kim, Namsoo; Uezu, Akiyoshi; Wang, Fan; Wetsel, William C; Weinberg, Richard J; Yin, Henry; Soderling, Scott H

    2015-06-01

    Psychiatric and neurodevelopmental disorders may arise from anomalies in long-range neuronal connectivity downstream of pathologies in dendritic spines. However, the mechanisms that may link spine pathology to circuit abnormalities relevant to atypical behavior remain unknown. Using a mouse model to conditionally disrupt a critical regulator of the dendritic spine cytoskeleton, the actin-related protein 2/3 complex (Arp2/3), we report here a molecular mechanism that unexpectedly reveals the inter-relationship of progressive spine pruning, elevated frontal cortical excitation of pyramidal neurons and striatal hyperdopaminergia in a cortical-to-midbrain circuit abnormality. The main symptomatic manifestations of this circuit abnormality are psychomotor agitation and stereotypical behaviors, which are relieved by antipsychotics. Moreover, this antipsychotic-responsive locomotion can be mimicked in wild-type mice by optogenetic activation of this circuit. Collectively these results reveal molecular and neural-circuit mechanisms, illustrating how diverse pathologies may converge to drive behaviors relevant to psychiatric disorders.

  7. Cortical spreading depression impairs oxygen delivery and metabolism in mice.

    Science.gov (United States)

    Yuzawa, Izumi; Sakadžić, Sava; Srinivasan, Vivek J; Shin, Hwa Kyoung; Eikermann-Haerter, Katharina; Boas, David A; Ayata, Cenk

    2012-02-01

    Cortical spreading depression (CSD) is associated with severe hypoperfusion in mice. Using minimally invasive multimodal optical imaging, we show that severe flow reductions during and after spreading depression are associated with a steep decline in cerebral metabolic rate of oxygen. Concurrent severe hemoglobin desaturation suggests that the oxygen metabolism becomes at least in part supply limited, and the decrease in cortical blood volume implicates vasoconstriction as the mechanism. In support of oxygen supply-demand mismatch, cortical nicotinamide adenine dinucleotide (NADH) fluorescence increases during spreading depression for at least 5 minutes, particularly away from parenchymal arterioles. However, modeling of tissue oxygen delivery shows that cerebral metabolic rate of oxygen drops more than predicted by a purely supply-limited model, raising the possibility of a concurrent reduction in oxygen demand during spreading depression. Importantly, a subsequent spreading depression triggered within 15 minutes evokes a monophasic flow increase superimposed on the oligemic baseline, which markedly differs from the response to the preceding spreading depression triggered in naive cortex. Altogether, these data suggest that CSD is associated with long-lasting oxygen supply-demand mismatch linked to severe vasoconstriction in mice.

  8. Methomyl poisoning presenting with decorticate posture and cortical blindness.

    Science.gov (United States)

    Lin, Chih-Ming

    2014-01-17

    Methomyl is a potent pesticide that is widely used in the field of agriculture. The systemic toxic effects of methomyl have been well described. However, the neurological effects of methomyl intoxication are not well understood. In this study, we report a 61-year-old Taiwanese man sent to our emergency department because of altered mental status. His family stated that he had consumed liquid methomyl in a suicide attempt. He was provided cardiopulmonary resuscitation because of unstable vital signs. He was then sent to an intensive care unit for close observation. On the second day of admission, he regained consciousness but exhibited irregular limb and torso posture. On the sixth day, he started to complain of blurred vision. An ophthalmologist was consulted but no obvious abnormalities could be identified. On suspicion of cerebral disease, a neurologist was consulted. Further examination revealed cortical blindness and decorticate posture. Cerebral magnetic resonance imaging (MRI) was arranged, which identified bilateral occipital regions lesions. The patient was administered normal saline and treated with aspirin and piracetam for 3 weeks in hospital. During the treatment period, his symptom of cortical blindness resolved, whereas his decorticate posture was refractory. Follow-up brain MRI results supported our clinical observations by indicating the disappearance of the bilateral occipital lesions and symmetrical putaminal high signal abnormalities. In this article, we briefly discuss the possible mechanisms underlying the cerebral effects of methomyl poisoning. Our study can provide clinicians with information on the manifestations of methomyl intoxication and an appropriate treatment direction.

  9. Methomyl poisoning presenting with decorticate posture and cortical blindness

    Directory of Open Access Journals (Sweden)

    Chih-Ming Lin

    2014-02-01

    Full Text Available Methomyl is a potent pesticide that is widely used in the field of agriculture. The systemic toxic effects of methomyl have been well described. However, the neurological effects of methomyl intoxication are not well understood. In this study, we report a 61-year-old Taiwanese man sent to our emergency department because of altered mental status. His family stated that he had consumed liquid methomyl in a suicide attempt. He was provided cardiopulmonary resuscitation because of unstable vital signs. He was then sent to an intensive care unit for close observation. On the second day of admission, he regained consciousness but exhibited irregular limb and torso posture. On the sixth day, he started to complain of blurred vision. An ophthalmologist was consulted but no obvious abnormalities could be identified. On suspicion of cerebral disease, a neurologist was consulted. Further examination revealed cortical blindness and decorticate posture. Cerebral magnetic resonance imaging (MRI was arranged, which identified bilateral occipital regions lesions. The patient was administered normal saline and treated with aspirin and piracetam for 3 weeks in hospital. During the treatment period, his symptom of cortical blindness resolved, whereas his decorticate posture was refractory. Follow-up brain MRI results supported our clinical observations by indicating the disappearance of the bilateral occipital lesions and symmetrical putaminal high signal abnormalities. In this article, we briefly discuss the possible mechanisms underlying the cerebral effects of methomyl poisoning. Our study can provide clinicians with information on the manifestations of methomyl intoxication and an appropriate treatment direction.

  10. Radiation-induced apoptosis in developing fetal rat cerebral cortex

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Woong Ki; Nam, Taek Keun; Lee, Min Cheol; Ahn, Sung Ja; Song, Ju Young; Park, Seung Jin; Nah, Byung Sik [College of Medicine, Chonnam National Univ., Gwangju (Korea, Republic of)

    2003-09-01

    The study was performed to investigate apoptosis by radiation in the developing fetal rat brain. Fetal brains were irradiated in utero between the 17th and 19th days of fetal life(E17-19) by linear accelerator. A dose of irradiation ranging from 1 Gy to 4 Gy was used to evaluate dose dependency. To test time dependency the rats were irradiated with 2 Gy and then the fetal brain specimens were removed at variable time course; 1, 3, 6, 12 and 24 hours after the onset of irradiation. Immunohistochemical staining using in situ TdT-mediated dUTP nick end labelling (TUNEL) technique was used for apoptotic cells. The cerebral cortex, including three zones of cortical zone (CZ), intermediate zone (IZ), and ventricular zone (VZ), was examined. TUNEL positive cells revealed typical features of apoptotic cells under light microscope in the fetal rat cerebral cortex. Apoptotic cells were not found in the cerebral cortex of non-irradiated fetal rats, but did appear in the entire cerebral cortex after 1 Gy irradiation, and were more extensive at the ventricular and intermediate zones than at the cortical zone. The extent of apoptosis was increased with increasing doses of radiation. Apoptosis reached the peak at 6 hours after the onset of 2 Gy irradiation and persisted until 24 hours. Typical morphologic features of apoptosis by irradiation were observed in the developing fetal rat cerebral cortex. It was more extensive at the ventricular and intermediate zones than at the cortical zone, which suggested that stem cells or early differentiating cells are more radiosensitive than differentiated cells of the cortical zone.

  11. Effects of crocin on reperfusion-induced oxidative/nitrative injury to cerebral microvessels after global cerebral ischemia.

    Science.gov (United States)

    Zheng, Yong-Qiu; Liu, Jian-Xun; Wang, Jan-Nong; Xu, Li

    2007-03-23

    This paper studied the effects of crocin, a pharmacologically active component of Crocus sativus L., on ischemia/reperfusion (I/R) injury in mice cerebral microvessels. Transient global cerebral ischemia (20 min), followed by 24 h of reperfusion, significantly promoted the generation of nitric oxide (NO) and malondialdehyde (MDA) in cortical microvascular homogenates, as well as markedly reduced the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and promoted the activity of nitric oxide synthase (NOs). Reperfusion for 24 h led to serous edema with substantial microvilli loss, vacuolation, membrane damage and mitochondrial injuries in cortical microvascular endothelial cells (CMEC). Furthermore, enhanced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and decreased expression of matrix metalloproteinase-9 (MMP-9) were detected in cortical microvessels after I (20 min)/R (24 h). Reperfusion for 24 h also induced membrane (functional) G protein-coupled receptor kinase 2 (GRK2) expression, while it reduced cytosol GRK2 expression. Pretreatment with crocin markedly inhibited oxidizing reactions and modulated the ultrastructure of CMEC in mice with 20 min of bilateral common carotid artery occlusion (BCCAO) followed by 24 h of reperfusion in vivo. Furthermore, crocin inhibited GRK2 translocation from the cytosol to the membrane and reduced ERK1/2 phosphorylation and MMP-9 expression in cortical microvessels. We propose that crocin protects the brain against excessive oxidative stress and constitutes a potential therapeutic candidate in transient global cerebral ischemia.

  12. Cerebral Palsy (For Kids)

    Science.gov (United States)

    ... CPR: A Real Lifesaver Kids Talk About: Coaches Cerebral Palsy KidsHealth > For Kids > Cerebral Palsy Print A A A What's in this article? ... the first word you spoke? For kids with cerebral palsy, called CP for short, taking a first step ...

  13. Influence of cadmium on Bcl-2, Bax and Caspase-3 mRNA transcription in rat's primary cultured cerebral cortical neurons%镉对大鼠大脑皮质神经细胞Bcl-2,Bax和Caspase-3mRNA转录的影响

    Institute of Scientific and Technical Information of China (English)

    袁燕; 孙娅; 江辰阳; 刘学忠; 顾建红; 卞建春; 刘宗平

    2012-01-01

    To investigate the effects of cadmium on transcription levels of apoptosis-related genes Bcl-2,Bax and Caspase-3 mRNA in primary cerebral cortical neurons of SD rats,the neurons were exposured to cadmium at different concentrations (0,5,10,20μmol/L ) for 12 h. MTT assay was applied to test the cell viability,and real-time fluorescent quantitative PCR was used to detect the transcription levels of Bcl-2,Bax and Caspase-3 mRNA. In comparison with the control group, the results showed that the cell viability decreased significantly with the higher concentration cadmium (P〈0.05 or P〈0.01). Additionally, transcription levels of Bax and Caspase-3 mRNA increased significantly (P〈0.01),but transcription level of Bcl-2 mRNA and Bcl-2/Bax decreased signifi- cantly (P〈0. 05,P〈0. 01). It was concluded that cadmium can inhibit the growth of neurons and regulate the transcription of apoptosis-related genes,including Bcl-2,Bax and Caspase-3.%为研究镉对大鼠大脑皮质神经细胞凋亡相关基因Bcl-2、Bax和Caspase-3mRNA转录水平的影响,选用不同浓度(0、5、10、20μmol/L)醋酸镉染毒大鼠大脑皮质神经细胞12h,用MTT法检测细胞存活率,实时荧光定量PCR检测Bcl-2、Bax和Caspase-3mRNA的转录水平,并计算Bcl-2/Bax的比值。结果表明,与对照组相比,各染毒组细胞存活率随染毒剂量增加而显著下降(P〈0.05或P〈0.01);Bax和Caspase-3mRNA转录水平极显著升高(P〈0.01),而Bcl-2mRNA转录水平显著降低(P〈0.05),Bcl-2/Bax极显著降低(P〈0.01)。说明镉能抑制大鼠大脑皮质神经细胞的生长,并可调节凋亡相关基因Bcl2、Bax和Caspase-3mRNA的转录。

  14. Effects of Milrinone continuous intravenous infusion on global cerebral oxygenation and cerebral vasospasm after cerebral aneurysm surgical clipping

    Directory of Open Access Journals (Sweden)

    Mohamed A. Ghanem

    2014-01-01

    Conclusions: Milrinone improved significantly the global cerebral oxygenation and reduced the incidence of cerebral vasospasm during the dangerous period of cerebral spasm after cerebral aneurysm clipping.

  15. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  16. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  17. Parallelizing quantum circuit synthesis

    OpenAIRE

    Di Matteo, Olivia; Mosca, Michele

    2016-01-01

    Quantum circuit synthesis is the process in which an arbitrary unitary operation is decomposed into a sequence of gates from a universal set, typically one which a quantum computer can implement both efficiently and fault-tolerantly. As physical implementations of quantum computers improve, the need is growing for tools which can effectively synthesize components of the circuits and algorithms they will run. Existing algorithms for exact, multi-qubit circuit synthesis scale exponentially in t...

  18. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  19. Neural perspectives of cerebral correlates of giftedness.

    Science.gov (United States)

    Chen, A C; Buckley, K C

    1988-07-01

    Giftedness is defined as some special endowment or propensity for creativity, skill, and eminent achievement, found in relatively few individuals among the population. A high order of mental power (IQ), creativity, and motivation (task commitment) appear to be the most universally recognized attributes of the gifted. This report summarizes current knowledge of the cerebral correlates of intelligence and creativity, including physiological measures of EEG, cortical power spectrum, brain evoked potentials, and positron emission tomography. Controversy, debates, contentions, formal hypotheses, and research issues are considered. We are especially interested in the formulation of the deterministic function of EEG-brain dynamics. A CHAOS modeling on hierarchy of cognitive organization and cerebral processing in the gifted is suggested.

  20. Asperger's syndrome with unusual cerebral pathology: Case report and literature review.

    Science.gov (United States)

    Liu, Liqiong; Vo, Van; Ware, Marcus; Xiong, Zhenggang

    2012-05-01

    A case of Asperger's syndrome with unusual cerebral pathological changes is reported. A 22-year-old male had been having diagnostic Asperger's syndrome since the age of eight and had epilepsy during the past two years. Radiological studies revealed a focal intra-axial cortical and subcortical cerebral lesion with hyper-intensity and non-enhancing contrast in the left frontal lobe. Histological and immunohistochemical studies demonstrated that the lesion consisted of cortical laminar disorganization, neuronal dysmorphism and increased heterotopic neurons in sub-cortical white matter. To our knowledge, this is the first case of Asperger's syndrome with focal cerebral pathological abnormalities rather than mini-columnar changes and the gyrial malformation reported in the literature.

  1. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  2. CMOS circuits manual

    CERN Document Server

    Marston, R M

    1995-01-01

    CMOS Circuits Manual is a user's guide for CMOS. The book emphasizes the practical aspects of CMOS and provides circuits, tables, and graphs to further relate the fundamentals with the applications. The text first discusses the basic principles and characteristics of the CMOS devices. The succeeding chapters detail the types of CMOS IC, including simple inverter, gate and logic ICs and circuits, and complex counters and decoders. The last chapter presents a miscellaneous collection of two dozen useful CMOS circuits. The book will be useful to researchers and professionals who employ CMOS circu

  3. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  4. Timergenerator circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Timer/Generator Circuits Manual is an 11-chapter text that deals mainly with waveform generator techniques and circuits. Each chapter starts with an explanation of the basic principles of its subject followed by a wide range of practical circuit designs. This work presents a total of over 300 practical circuits, diagrams, and tables.Chapter 1 outlines the basic principles and the different types of generator. Chapters 2 to 9 deal with a specific type of waveform generator, including sine, square, triangular, sawtooth, and special waveform generators pulse. These chapters also include pulse gen

  5. Security electronics circuits manual

    CERN Document Server

    MARSTON, R M

    1998-01-01

    Security Electronics Circuits Manual is an invaluable guide for engineers and technicians in the security industry. It will also prove to be a useful guide for students and experimenters, as well as providing experienced amateurs and DIY enthusiasts with numerous ideas to protect their homes, businesses and properties.As with all Ray Marston's Circuits Manuals, the style is easy-to-read and non-mathematical, with the emphasis firmly on practical applications, circuits and design ideas. The ICs and other devices used in the practical circuits are modestly priced and readily available ty

  6. MOS integrated circuit design

    CERN Document Server

    Wolfendale, E

    2013-01-01

    MOS Integral Circuit Design aims to help in the design of integrated circuits, especially large-scale ones, using MOS Technology through teaching of techniques, practical applications, and examples. The book covers topics such as design equation and process parameters; MOS static and dynamic circuits; logic design techniques, system partitioning, and layout techniques. Also featured are computer aids such as logic simulation and mask layout, as well as examples on simple MOS design. The text is recommended for electrical engineers who would like to know how to use MOS for integral circuit desi

  7. Printed circuit board industry.

    Science.gov (United States)

    LaDou, Joseph

    2006-05-01

    The printed circuit board is the platform upon which microelectronic components such as semiconductor chips and capacitors are mounted. It provides the electrical interconnections between components and is found in virtually all electronics products. Once considered low technology, the printed circuit board is evolving into a high-technology product. Printed circuit board manufacturing is highly complicated, requiring large equipment investments and over 50 process steps. Many of the high-speed, miniaturized printed circuit boards are now manufactured in cleanrooms with the same health and safety problems posed by other microelectronics manufacturing. Asia produces three-fourths of the world's printed circuit boards. In Asian countries, glycol ethers are the major solvents used in the printed circuit board industry. Large quantities of hazardous chemicals such as formaldehyde, dimethylformamide, and lead are used by the printed circuit board industry. For decades, chemically intensive and often sloppy manufacturing processes exposed tens of thousands of workers to a large number of chemicals that are now known to be reproductive toxicants and carcinogens. The printed circuit board industry has exposed workers to high doses of toxic metals, solvents, acids, and photolithographic chemicals. Only recently has there been any serious effort to diminish the quantity of lead distributed worldwide by the printed circuit board industry. Billions of electronics products have been discarded in every region of the world. This paper summarizes recent regulatory and enforcement efforts.

  8. Acute Headache at Emergency Department: Reversible Cerebral Vasoconstriction Syndrome Complicated by Subarachnoid Haemorrhage and Cerebral Infarction

    Directory of Open Access Journals (Sweden)

    M. Yger

    2015-01-01

    Full Text Available Introduction. Reversible cerebral vasoconstriction syndrome is becoming widely accepted as a rare cause of both ischemic and haemorrhagic stroke and should be evocated in case of thunderclap headaches associated with stroke. We present the case of a patient with ischemic stroke associated with cortical subarachnoid haemorrhage (cSAH and reversible diffuse arteries narrowing, leading to the diagnosis of reversible vasoconstriction syndrome. Case Report. A 48-year-old woman came to the emergency department because of an unusual thunderclap headache. The computed tomography of the brain completed by CT-angiography was unremarkable. Eleven days later, she was readmitted because of a left hemianopsia. One day after her admission, she developed a sudden left hemiparesis. The brain MRI showed ischemic lesions in the right frontal and occipital lobe and diffuse cSAH. The angiography showed vasoconstriction of the right anterior cerebral artery and stenosis of both middle cerebral arteries. Nimodipine treatment was initiated and vasoconstriction completely regressed on day 16 after the first headache. Conclusion. Our case shows a severe reversible cerebral vasoconstriction syndrome where both haemorrhagic and ischemic complications were present at the same time. The history we reported shows that reversible cerebral vasoconstriction syndrome is still underrecognized, in particular in general emergency departments.

  9. Effects of rapamycin on cerebral oxygen supply and consumption during reperfusion after cerebral ischemia.

    Science.gov (United States)

    Chi, O Z; Barsoum, S; Vega-Cotto, N M; Jacinto, E; Liu, X; Mellender, S J; Weiss, H R

    2016-03-01

    Activation of the mammalian target of rapamycin (mTOR) leads to cell growth and survival. We tested the hypothesis that inhibition of mTOR would increase infarct size and decrease microregional O2 supply/consumption balance after cerebral ischemia-reperfusion. This was tested in isoflurane-anesthetized rats with middle cerebral artery blockade for 1h and reperfusion for 2h with and without rapamycin (20mg/kg once daily for two days prior to ischemia). Regional cerebral blood flow was determined using a C(14)-iodoantipyrine autoradiographic technique. Regional small-vessel arterial and venous oxygen saturations were determined microspectrophotometrically. The control ischemic-reperfused cortex had a similar blood flow and O2 consumption to the contralateral cortex. However, microregional O2 supply/consumption balance was significantly reduced in the ischemic-reperfused cortex. Rapamycin significantly increased cerebral O2 consumption and further reduced O2 supply/consumption balance in the reperfused area. This was associated with an increased cortical infarct size (13.5±0.8% control vs. 21.5±0.9% rapamycin). We also found that ischemia-reperfusion increased AKT and S6K1 phosphorylation, while rapamycin decreased this phosphorylation in both the control and ischemic-reperfused cortex. This suggests that mTOR is important for not only cell survival, but also for the control of oxygen balance after cerebral ischemia-reperfusion.

  10. Cerebral microangiopathies; Zerebrale Mikroangiopathien

    Energy Technology Data Exchange (ETDEWEB)

    Linn, Jennifer [Klinikum der Universitaet Muenchen (Germany). Abt. fuer Neuroradiologie

    2011-03-15

    Cerebral microangiopathies are a very heterogenous group of diseases characterized by pathological changes of the small cerebral vessels. They account for 20 - 30 % of all ischemic strokes. Degenerative microangiopathy and sporadic cerebral amyloid angiography represent the typical acquired cerebral microangiopathies, which are found in over 90 % of cases. Besides, a wide variety of rare, hereditary microangiopathy exists, as e.g. CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), Fabrys disease and MELAS syndrome (Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes). (orig.)

  11. Cortical thickness difference across the central sulcus visualized in the presence of vasogenic edema

    Energy Technology Data Exchange (ETDEWEB)

    Togao, Osamu [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)], E-mail: togao@dr.hosp.kyushu-u.ac.jp; Yoshiura, Takashi; Mihara, Futoshi; Noguchi, Tomoyuki; Hiwatashi, Akio; Yamashita, Koji; Yoshitake, Tadamasa; Honda, Hiroshi [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)

    2008-05-15

    Purpose: To confirm the cortical thickness difference across the central sulcus (CS) visualized in the presence of vasogenic edema on MRI. Materials and methods: T2-weighted images of 70 cerebral hemispheres showing vasogenic edema infiltrating into subcortical white matter around the CS were studied retrospectively. Two neuroradiologists measured the cortical thickness of the anterior and posterior banks of the CS, precentral sulci (PrCS), and postcentral sulci (PoCS). Additionally, we compared the cortical thickness of the anterior and posterior banks of each sulcus visually using a grading scale. Results: On T2-weighted images, the cerebral cortex was highlighted by a high signal-intensity vasogenic edema in the adjacent white matter, and its thickness was readily measurable. The unique cortical thickness difference between the anterior and posterior banks of the CS were confirmed with measurements of 2.67 and 1.48 mm (p < 0.0001). The cortical measurements across other cerebral sulci were 2.04 and 1.95 mm (NS) for the PrCS, and 1.67 and 1.77 mm (NS) for the PoCS. The cortical thickness ratios were 1.86 for the CS, 1.05 for the PrCS, and 0.96 for the PoCS. On visual evaluation, the anterior bank of the CS was thicker than the posterior bank in 93% (65/70). For the PrCS and PoCS, the thickness of the anterior and posterior banks appeared to be equal in over 70% of the patients. Conclusion: A prominent cortical thickness difference across the CS in the presence of vasogenic edema was confirmed. This finding is considered to facilitate the identification of the CS in patients with brain tumors.

  12. Object recognition by artificial cortical maps.

    Science.gov (United States)

    Plebe, Alessio; Domenella, Rosaria Grazia

    2007-09-01

    Object recognition is one of the most important functions of the human visual system, yet one of the least understood, this despite the fact that vision is certainly the most studied function of the brain. We understand relatively well how several processes in the cortical visual areas that support recognition capabilities take place, such as orientation discrimination and color constancy. This paper proposes a model of the development of object recognition capability, based on two main theoretical principles. The first is that recognition does not imply any sort of geometrical reconstruction, it is instead fully driven by the two dimensional view captured by the retina. The second assumption is that all the processing functions involved in recognition are not genetically determined or hardwired in neural circuits, but are the result of interactions between epigenetic influences and basic neural plasticity mechanisms. The model is organized in modules roughly related to the main visual biological areas, and is implemented mainly using the LISSOM architecture, a recent neural self-organizing map model that simulates the effects of intercortical lateral connections. This paper shows how recognition capabilities, similar to those found in brain ventral visual areas, can develop spontaneously by exposure to natural images in an artificial cortical model.

  13. Maduración cerebral y desarrollo cognoscitivo

    OpenAIRE

    Mónica Rosselli

    2003-01-01

    La maduración cerebral se correlaciona con muchos de los cambios cognoscitivos y de comportamiento observados durante la infancia y la adolescencia. En este artículo se revisa el concepto de maduración cerebral y su asociación con el desarrollo de la preferencia manual, del lenguaje verbal y de la función ejecutiva en el niño. Se describe el incremento de las arborizaciones dendríticas como el cambio cortical más importante asociado a la adquisición de funciones cognoscitivas complejas. Se as...

  14. Analysis of cranial CT-scan findings in cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Wada, F.; Andoh, T.; Une, K.; Takamatsu, T. (Kitakyushu Municipal Sogo-Ryoiku Center (Japan))

    1981-06-01

    CT-scan findings of 87 cerebral palsied children were studied. They consist of 23 cases of spastic quadriplegia, 9 cases of diplegia, 12 cases of paraplegia, 24 cases of athetosis and mixed type, and 19 cases of hemiplegia. In the former four types, ventricular dilatation and cortical atrophy were measured and abnormal changes in cerebral substance and cerebellar atrophy were observed. Spastic quadriplegia showed most intense changes in every aspect of the abnormalities, while paraplegia had almost normal appearance. Athetosis and mixed type had moderate changes. Hemiplegia always showed asymmetrical view on CT-scan, dilatation of lateral ventricle or atrophy of hemisphere in contralateral side being observed.

  15. Emerging roles of neural stem cells in cerebral cortex development and evolution.

    Science.gov (United States)

    Borrell, Víctor; Reillo, Isabel

    2012-07-01

    Expansion and folding of the cerebral cortex are landmark features of mammalian brain evolution, which are recapitulated during embryonic development. Neural stem cells and their derived germinal cells are coordinated during cerebral cortex development to produce the appropriate amounts and types of neurons. This process is further complicated in gyrencephalic species, where newborn neurons must disperse in the tangential axis to expand the cerebral cortex in surface area. Here, we review advances that have been made over the last decade in understanding the nature and diversity of telencephalic neural stem cells and their roles in cortical development, and we discuss recent progress on how newly identified types of cortical progenitor cell populations may have evolved to drive the expansion and folding of the mammalian cerebral cortex.

  16. Anxiety and cerebral blood flow during behavioral challenge. Dissociation of central from peripheral and subjective measures

    Energy Technology Data Exchange (ETDEWEB)

    Zohar, J.; Insel, T.R.; Berman, K.F.; Foa, E.B.; Hill, J.L.; Weinberger, D.R.

    1989-06-01

    To investigate the relationship between anxiety and regional cerebral blood flow, we administered behavioral challenges to 10 patients with obsessive-compulsive disorder while measuring regional cerebral blood flow with the xenon 133 inhalation technique. Each patient was studied under three conditions: relaxation, imaginal flooding, and in vivo (actual) exposure to the phobic stimulus. Subjective anxiety, obsessive-compulsive ratings, and autonomic measures (heart rate, blood pressure) increased significantly, but respiratory rate and PCO/sub 2/ did not change across the three conditions. Regional cerebral blood flow increased slightly (in the temporal region) during imaginal flooding, but decreased markedly in several cortical regions during in vivo exposure, when anxiety was highest by subjective and peripheral autonomic measures. These results demonstrate that intense anxiety can be associated with decreased rather than increased cortical perfusion and that ostensibly related states of anxiety (eg, anticipatory and obsessional anxiety) may be associated with opposite effects on regional cerebral blood flow.

  17. Revisiting the enigmatic cortical calretinin-expressing interneurons

    Directory of Open Access Journals (Sweden)

    Bruno eCauli

    2014-06-01

    Full Text Available Cortical calretinin (CR-expressing interneurons represent a heterogeneous subpopulation of about 10-30% of GABAergic interneurons, which altogether total ca. 12-20% of all cortical neurons. In the rodent neocortex, CR cells display different somatodendritic morphologies ranging from bipolar to multipolar but the bipolar cells and their variations dominate. They are also diverse at the molecular level as they were shown to express numerous neuropeptides in different combinations including vasoactive intestinal polypeptide (VIP, cholecystokinin (CCK, neurokinin B (NKB corticotrophin releasing factor (CRF, enkephalin (Enk but also neuropeptide Y (NPY and somatostatin (SOM to a lesser extent. CR-expressing interneurons exhibit different firing behaviors such as adapting, bursting or irregular. They mainly originate from the caudal ganglionic eminence (CGE but a subpopulation also derives from the dorsal part of the medial ganglionic eminence (MGE. Cortical GABAergic CR-expressing interneurons can be divided in two main populations: VIP-bipolar interneurons deriving from the CGE and SOM-Martinotti-like interneurons originating in the dorsal MGE. Although bipolar cells account for the majority of CR-expressing interneurons, the roles they play in cortical neuronal circuits and in the more general metabolic physiology of the brain remain elusive and enigmatic. The aim of this review is, firstly, to provide a comprehensive view of the morphological, molecular and electrophysiological features defining this cell type. We will, secondly, also summarize what is known about their place in the cortical circuit, their modulation by subcortical afferents and the functional roles they might play in neuronal processing and energy metabolism.

  18. Cortical hypometabolism and hypoperfusion in Parkinson's disease is extensive

    DEFF Research Database (Denmark)

    Borghammer, Per; Chakravarty, Mallar; Jonsdottir, Kristjana Yr;

    2010-01-01

    Recent cerebral blood flow (CBF) and glucose consumption (CMRglc) studies of Parkinson's disease (PD) revealed conflicting results. Using simulated data, we previously demonstrated that the often-reported subcortical hypermetabolism in PD could be explained as an artifact of biased global mean (GM......) normalization, and that low-magnitude, extensive cortical hypometabolism is best detected by alternative data-driven normalization methods. Thus, we hypothesized that PD is characterized by extensive cortical hypometabolism but no concurrent widespread subcortical hypermetabolism and tested it on three...... independent samples of PD patients. We compared SPECT CBF images of 32 early-stage and 33 late-stage PD patients with that of 60 matched controls. We also compared PET FDG images from 23 late-stage PD patients with that of 13 controls. Three different normalization methods were compared: (1) GM normalization...

  19. Cortical venous thrombosis following exogenous androgen use for bodybuilding.

    Science.gov (United States)

    Sveinsson, Olafur; Herrman, Lars

    2013-02-05

    There are only a few reports of patients developing cerebral venous sinus thrombosis (CVST) after androgen therapy. We present a young man who developed cortical venous thrombosis after using androgens to increase muscle mass. He was hospitalised for parasthesia and dyspraxia in the left hand followed by a generalised tonic-clonic seizure. At admission, he was drowsy, not fully orientated, had sensory inattention, pronation drift and a positive extensor response, all on the left side. The patient had been using anabolic steroids (dainabol 20 mg/day) for the last month for bodybuilding. CT angiography showed a right cortical venous thrombosis. Anticoagulation therapy was started with intravenous heparin for 11 days and oral anticoagulation (warfarin) thereafter. A control CT angiography 4 months later showed resolution of the thrombosis. He recovered fully.

  20. Acute cortical blindness due to posterior reversible encephalopathy.

    Science.gov (United States)

    Nguyen-Lam, Jenny; Kiernan, Matthew C

    2008-10-01

    An acutely hypertensive 55 year-old male experienced seizures and cortical blindness post-operatively. CT scans demonstrated hypointensities in the occipital lobes bilaterally. MRI revealed symmetrical bilateral hyperintense signals in the same region, involving both grey and white matter. Thromboembolic screening investigations including vertebral artery doppler studies were normal and echocardiography demonstrated borderline left ventricular hypertrophy. A diagnosis of posterior reversible encephalopathy syndrome (PRES) was reached and there was complete resolution of blindness with antihypertensive therapy. This case supports the vasogenic theory of PRES which suggests that sustained high grade fluctuations in blood pressure lead to a reduction in cerebral vascular autoregulatory function. The resultant failure of compensatory vasoconstriction to prevent hyperperfusion causes fluid to extravasate into the occipital lobes, which in the present case resulted in cortical blindness.

  1. Synchronizing Hyperchaotic Circuits

    DEFF Research Database (Denmark)

    Tamasevicius, Arunas; Cenys, Antanas; Namajunas, Audrius

    1997-01-01

    Regarding possible applications to secure communications the technique of synchronizing hyperchaotic circuits with a single dynamical variable is discussed. Several specific examples including the fourth-order circuits with two positive Lyapunov exponents as well as the oscillator with a delay line...... characterized by multiple positive Lyapunov exponents are reviewd....

  2. Genetic circuit design automation.

    Science.gov (United States)

    Nielsen, Alec A K; Der, Bryan S; Shin, Jonghyeon; Vaidyanathan, Prashant; Paralanov, Vanya; Strychalski, Elizabeth A; Ross, David; Densmore, Douglas; Voigt, Christopher A

    2016-04-01

    Computation can be performed in living cells by DNA-encoded circuits that process sensory information and control biological functions. Their construction is time-intensive, requiring manual part assembly and balancing of regulator expression. We describe a design environment, Cello, in which a user writes Verilog code that is automatically transformed into a DNA sequence. Algorithms build a circuit diagram, assign and connect gates, and simulate performance. Reliable circuit design requires the insulation of gates from genetic context, so that they function identically when used in different circuits. We used Cello to design 60 circuits forEscherichia coli(880,000 base pairs of DNA), for which each DNA sequence was built as predicted by the software with no additional tuning. Of these, 45 circuits performed correctly in every output state (up to 10 regulators and 55 parts), and across all circuits 92% of the output states functioned as predicted. Design automation simplifies the incorporation of genetic circuits into biotechnology projects that require decision-making, control, sensing, or spatial organization.

  3. A Virtual Circuits Lab

    Science.gov (United States)

    Vick, Matthew E.

    2010-01-01

    The University of Colorado's Physics Education Technology (PhET) website offers free, high-quality simulations of many physics experiments that can be used in the classroom. The Circuit Construction Kit, for example, allows students to safely and constructively play with circuit components while learning the mathematics behind many circuit…

  4. Adenomatous polyposis coli is required for early events in the normal growth and differentiation of the developing cerebral cortex

    Directory of Open Access Journals (Sweden)

    Price David J

    2009-01-01

    Full Text Available Abstract Background Adenomatous polyposis coli (Apc is a large multifunctional protein known to be important for Wnt/β-catenin signalling, cytoskeletal dynamics, and cell polarity. In the developing cerebral cortex, Apc is expressed in proliferating cells and its expression increases as cells migrate to the cortical plate. We examined the consequences of loss of Apc function for the early development of the cerebral cortex. Results We used Emx1Cre to inactivate Apc specifically in proliferating cerebral cortical cells and their descendents starting from embryonic day 9.5. We observed reduction in the size of the mutant cerebral cortex, disruption to its organisation, and changes in the molecular identity of its cells. Loss of Apc leads to a decrease in the size of the proliferative pool, disrupted interkinetic nuclear migration, and increased apoptosis. β-Catenin, pericentrin, and N-cadherin proteins no longer adopt their normal high concentration at the apical surface of the cerebral cortical ventricular zone, indicating that cell polarity is disrupted. Consistent with enhanced Wnt/β-catenin signalling resulting from loss of Apc we found increased levels of TCF/LEF-dependent transcription and expression of endogenous Wnt/β-catenin target genes (Axin2 (conductin, Lef1, and c-myc in the mutant cerebral cortex. In the Apc mutant cerebral cortex the expression of transcription factors Foxg1, Pax6, Tbr1, and Tbr2 is drastically reduced compared to normal and many cells ectopically express Pax3, Wnt1, and Wt1 (but not Wnt2b, Wnt8b, Ptc, Gli1, Mash1, Olig2, or Islet1. This indicates that loss of Apc function causes cerebral cortical cells to lose their normal identity and redirect to fates normally found in more posterior-dorsal regions of the central nervous system. Conclusion Apc is required for multiple aspects of early cerebral cortical development, including the regulation of cell number, interkinetic nuclear migration, cell polarity, and

  5. The Unique Brain Anatomy of Meditation Practitioners: Alterations in Cortical Gyrification

    Directory of Open Access Journals (Sweden)

    Eileen eLuders

    2012-02-01

    Full Text Available Several cortical regions are reported to vary in meditation practitioners. However, since prior analyses were focused on examining gray matter or cortical thickness, additional effects with respect to other cortical features might have remained undetected. Gyrification (the pattern and degree of cortical folding is an important cerebral characteristic related to the geometry of the brain’s surface. Cortical folding occurs early in development and might be linked to behavioral traits. Thus, exploring cortical gyrification in long-term meditators may provide additional clues with respect to the underlying anatomical correlates of meditation. This study examined cortical gyrification in a large sample (n=100 of meditators and controls, carefully matched for sex and age. Cortical gyrification was established via calculating mean curvature across thousands of vertices on individual cortical surface models. Pronounced group differences indicating larger gyrification in meditators were evident within the left precentral gyrus, right fusiform gyrus, right cuneus, as well as left and right anterior dorsal insula (the latter representing the global significance maximum. Although the exact functional implications of larger cortical gyrification remain to be established, these findings suggest the insula to be a key structure involved in aspects of meditation. For example, variations in insular complexity could affect the regulation of well-known distractions in the process of meditation, such as daydreaming, mind-wandering, and projections into past or future. Moreover, given that meditators are masters in introspection, awareness, and emotional control, increased insular gyrification may reflect an ideal integration of autonomic, affective, and cognitive processes. Due to the cross-sectional nature of this study, further research is necessary determine the relative contribution of nature and nurture to links between cortical gyrification and meditation.

  6. Neurons and circuits for odor processing in the piriform cortex.

    Science.gov (United States)

    Bekkers, John M; Suzuki, Norimitsu

    2013-07-01

    Increased understanding of the early stages of olfaction has lead to a renewed interest in the higher brain regions responsible for forming unified 'odor images' from the chemical components detected by the nose. The piriform cortex, which is one of the first cortical destinations of olfactory information in mammals, is a primitive paleocortex that is critical for the synthetic perception of odors. Here we review recent work that examines the cellular neurophysiology of the piriform cortex. Exciting new findings have revealed how the neurons and circuits of the piriform cortex process odor information, demonstrating that, despite its superficial simplicity, the piriform cortex is a remarkably subtle and intricate neural circuit.

  7. Analog VLSI Circuits for Short-Term Dynamic Synapses

    Directory of Open Access Journals (Sweden)

    Shih-Chii Liu

    2003-06-01

    Full Text Available Short-term dynamical synapses increase the computational power of neuronal networks. These synapses act as additional filters to the inputs of a neuron before the subsequent integration of these signals at its cell body. In this work, we describe a model of depressing and facilitating synapses derived from a hardware circuit implementation. This model is equivalent to theoretical models of short-term synaptic dynamics in network simulations. These circuits have been added to a network of leaky integrate-and-fire neurons. A cortical model of direction-selectivity that uses short-term dynamic synapses has been implemented with this network.

  8. Quantitative Magnetic Resonance Imaging of Cortical Multiple Sclerosis Pathology

    Directory of Open Access Journals (Sweden)

    Christine L. Tardif

    2012-01-01

    Full Text Available Although significant improvements have been made regarding the visualization and characterization of cortical multiple sclerosis (MS lesions using magnetic resonance imaging (MRI, cortical lesions (CL continue to be under-detected in vivo, and we have a limited understanding of the causes of GM pathology. The objective of this study was to characterize the MRI signature of CLs to help interpret the changes seen in vivo and elucidate the factors limiting their visualization. A quantitative 3D high-resolution (350 μm isotropic MRI study at 3 Tesla of a fixed post mortem cerebral hemisphere from a patient with MS is presented in combination with matched immunohistochemistry. Type III subpial lesions are characterized by an increase in T1, T2 and M0, and a decrease in MTR in comparison to the normal appearing cortex (NAC. All quantitative MR parameters were associated with cortical GM myelin content, while T1 showed the strongest correlation. The histogram analysis showed extensive overlap between CL and NAC for all MR parameters and myelin content. This is due to the poor contrast in myelin content between CL and NAC in comparison to the variability in myelo-architecture throughout the healthy cortex. This latter comparison is highlighted by the representation of T1 times on cortical surfaces at several laminar depths.

  9. Functional Doppler optical coherence tomography for cortical blood flow imaging

    Science.gov (United States)

    Yu, Lingfeng; Liu, Gangjun; Nguyen, Elaine; Choi, Bernard; Chen, Zhongping

    2010-02-01

    Optical methods have been widely used in basic neuroscience research to study the cerebral blood flow dynamics in order to overcome the low spatial resolution associated with magnetic resonance imaging and positron emission tomography. Although laser Doppler imaging and laser speckle imaging can map out en face cortical hemodynamics and columns, depth resolution is not available. Two-photon microscopy has been used for mapping cortical activity. However, flow measurement requires fluorescent dye injection, which can be problematic. The noninvasive and high resolution tomographic capabilities of optical coherence tomography make it a promising technique for mapping depth resolved cortical blood flow. Here, we present a functional Doppler optical coherence tomography (OCT) imaging modality for quantitative evaluation of cortical blood flow in a mouse model. Fast, repeated, Doppler OCT scans across a vessel of interest were performed to record flow dynamic information with a high temporal resolution of the cardiac cycles. Spectral Doppler analysis of continuous Doppler images demonstrates how the velocity components and longitudinally projected flow-volume-rate change over time, thereby providing complementary temporal flow information to the spatially distributed flow information of Doppler OCT. The proposed functional Doppler OCT imaging modality can be used to diagnose vessel stenosis/blockage or monitor blood flow changes due to pharmacological agents/neuronal activities. Non-invasive in-vivo mice experiments were performed to verify the capabilities of function Doppler OCT.

  10. Abnormalities in cortical gray matter density in borderline personality disorder

    Science.gov (United States)

    Rossi, Roberta; Lanfredi, Mariangela; Pievani, Michela; Boccardi, Marina; Rasser, Paul E; Thompson, Paul M; Cavedo, Enrica; Cotelli, Maria; Rosini, Sandra; Beneduce, Rossella; Bignotti, Stefano; Magni, Laura R; Rillosi, Luciana; Magnaldi, Silvia; Cobelli, Milena; Rossi, Giuseppe; Frisoni, Giovanni B

    2015-01-01

    Background Borderline personality disorder (BPD) is a chronic condition with a strong impact on patients‘ affective,cognitive and social functioning. Neuroimaging techniques offer invaluable tools to understand the biological substrate of the disease. We aimed to investigate gray matter alterations over the whole cortex in a group of Borderline Personality Disorder (BPD) patients compared to healthy controls (HC). Methods Magnetic resonance-based cortical pattern matching was used to assess cortical gray matter density (GMD) in 26 BPD patients and in their age- and sex-matched HC (age: 38±11; females: 16, 61%). Results BPD patients showed widespread lower cortical GMD compared to HC (4% difference) with peaks of lower density located in the dorsal frontal cortex, in the orbitofrontal cortex, the anterior and posterior cingulate, the right parietal lobe, the temporal lobe (medial temporal cortex and fusiform gyrus) and in the visual cortex (p<0.005). Our BPD subjects displayed a symmetric distribution of anomalies in the dorsal aspect of the cortical mantle, but a wider involvement of the left hemisphere in the mesial aspect in terms of lower density. A few restricted regions of higher density were detected in the right hemisphere. All regions remained significant after correction for multiple comparisons via permutation testing. Conclusions BPD patients feature specific morphology of the cerebral structures involved in cognitive and emotional processing and social cognition/mentalization, consistent with clinical and functional data. PMID:25561291

  11. Linear superposition of sensory-evoked and ongoing cortical hemodynamics

    Directory of Open Access Journals (Sweden)

    Mohamad Saka

    2010-08-01

    Full Text Available Modern non-invasive brain imaging techniques utilise changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. To investigate this issue, 2-dimensional optical imaging spectroscopy was used to measure cortical hemodynamics in response to sensory stimuli in anaesthetised rodents Pre-stimulus cortical hemodynamics displayed spontaneous periodic fluctuations and as such, data from individual stimulus presentation trials were assigned to one of four groups depending on the phase angle of pre-stimulus hemodynamic fluctuations and averaged. This analysis revealed that sensory evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase angle of ongoing fluctuations at stimulus onset. To investigate the origin of this phenomenon, ‘null-trails’ were collected without stimulus presentation. Subtraction of phase averaged ‘null trials’ from their phase averaged stimulus-evoked counterparts resulted in four similar time series that resembled the mean stimulus-evoked response. These analyses suggest that linear superposition of evoked and ongoing cortical hemodynamic changes may be a property of the structure of inter-trial variability.

  12. Transient cortical blindness following vertebral angiography: a case report.

    Science.gov (United States)

    Lo, Lai Wan; Chan, Ho Fung; Ma, Ka Fai; Cheng, Lik Fai; Chan, Tony Kt

    2015-02-01

    Transient cortical blindness (TCB) is a rare but well-known complication of cerebral angiography. Its pathophysiology remains uncertain. We would like to report a case of TCB in a patient during a follow up vertebral angiogram for post-coil embolization of left posterior inferior cerebellar artery aneurysm. Patient's vision was resumed spontaneously within 24 hours after angiography, with no residual neurological deficit in subsequent clinical follow up. Multi-modality imaging evaluation including vertebral angiography, brain CT and MRI performed on same day are presented.

  13. Cortical myoclonus during IV thrombolysis for ischemic stroke

    Directory of Open Access Journals (Sweden)

    Carla Bentes

    2014-01-01

    Full Text Available We describe a patient with an acute middle cerebral artery ischemic stroke developing subtle involuntary movements of the paretic upper limb with cortical origin during rt-PA perfusion. Despite the multiple potential pathophysiological mechanisms for the relationship between thrombolysis and epileptic activity, seizures during this procedure are scarcely reported. Our hypothesis is that subtle and transient clinical seizures, like those described in our patient, may not be detected or are misdiagnosed as nonepileptic involuntary movements. We aimed to draw attention to the recognition challenge of this paroxysmal motor behavior, highlighting this clinical and neurophysiological identification using video recording and back-average analysis of the EEG.

  14. Desviación disociada. Estrabismo de origen cortical

    OpenAIRE

    Martín Gallegos-Duarte; Jorge Mendiola-Santibáñez; Juan José Ortiz-Retana; Bernardo Rubín de Celis-Monteverde; Rosana Vidal-Pineda; Arleth Sigala-Zamora

    2007-01-01

    Objetivos: Determinar las alteraciones corticales relacionadas con el origen de la desviación disociada. Material y métodos: Estudio prospectivo, descriptivo y observacional que incluyó a 10 niños con diagnóstico de desviación horizontal disociada, sin evidencia previa de daño neuronal. Se determinó la dominancia manual, cerebral y ocular, el estado sensorial y el perfil perceptual visual. Se analizó la respuesta cortical a diferentes estímulos: luminoso, hiperventilación, movimientos de segu...

  15. Construction of 4D high-definition cortical surface atlases of infants: Methods and applications.

    Science.gov (United States)

    Li, Gang; Wang, Li; Shi, Feng; Gilmore, John H; Lin, Weili; Shen, Dinggang

    2015-10-01

    In neuroimaging, cortical surface atlases play a fundamental role for spatial normalization, analysis, visualization, and comparison of results across individuals and different studies. However, existing cortical surface atlases created for adults are not suitable for infant brains during the first two postnatal years, which is the most dynamic period of postnatal structural and functional development of the highly-folded cerebral cortex. Therefore, spatiotemporal cortical surface atlases for infant brains are highly desired yet still lacking for accurate mapping of early dynamic brain development. To bridge this significant gap, leveraging our infant-dedicated computational pipeline for cortical surface-based analysis and the unique longitudinal infant MRI dataset acquired in our research center, in this paper, we construct the first spatiotemporal (4D) high-definition cortical surface atlases for the dynamic developing infant cortical structures at seven time points, including 1, 3, 6, 9, 12, 18, and 24 months of age, based on 202 serial MRI scans from 35 healthy infants. For this purpose, we develop a novel method to ensure the longitudinal consistency and unbiasedness to any specific subject and age in our 4D infant cortical surface atlases. Specifically, we first compute the within-subject mean cortical folding by unbiased groupwise registration of longitudinal cortical surfaces of each infant. Then we establish longitudinally-consistent and unbiased inter-subject cortical correspondences by groupwise registration of the geometric features of within-subject mean cortical folding across all infants. Our 4D surface atlases capture both longitudinally-consistent dynamic mean shape changes and the individual variability of cortical folding during early brain development. Experimental results on two independent infant MRI datasets show that using our 4D infant cortical surface atlases as templates leads to significantly improved accuracy for spatial normalization

  16. TDCS increases cortical excitability: direct evidence from TMS-EEG.

    Science.gov (United States)

    Romero Lauro, Leonor J; Rosanova, Mario; Mattavelli, Giulia; Convento, Silvia; Pisoni, Alberto; Opitz, Alexander; Bolognini, Nadia; Vallar, Giuseppe

    2014-09-01

    Despite transcranial direct current stimulation (tDCS) is increasingly used in experimental and clinical settings, its precise mechanisms of action remain largely unknown. At a neuronal level, tDCS modulates the resting membrane potential in a polarity-dependent fashion: anodal stimulation increases cortical excitability in the stimulated region, while cathodal decreases it. So far, the neurophysiological underpinnings of the immediate and delayed effects of tDCS, and to what extent the stimulation of a given cerebral region may affect the activity of anatomically connected regions, remain unclear. In the present study, we used a combination of Transcranial Magnetic Stimulation (TMS) and Electroencephalography (EEG) in order to explore local and global cortical excitability modulation during and after active and sham tDCS. Single pulse TMS was delivered over the left posterior parietal cortex (PPC), before, during, and after 15 min of tDCS over the right PPC, while EEG was recorded from 60 channels. For each session, indexes of global and local cerebral excitability were obtained, computed as global and local mean field power (Global Mean Field Power, GMFP and Local Mean Field Power, LMFP) on mean TMS-evoked potentials (TEPs) for three temporal windows: 0-50, 50-100, and 100-150 msec. The global index was computed on all 60 channels. The local indexes were computed in six clusters of electrodes: left and right in frontal, parietal and temporal regions. GMFP increased, compared to baseline, both during and after active tDCS in the 0-100 msec temporal window. LMFP increased after the end of stimulation in parietal and frontal clusters bilaterally, while no difference was found in the temporal clusters. In sum, a diffuse rise of cortical excitability occurred, both during and after active tDCS. This evidence highlights the spreading of the effects of anodal tDCS over remote cortical regions of stimulated and contralateral hemispheres.

  17. Protective effects of berberine against amyloid beta-induced toxicity in cultured rat cortical neurons

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Yanjun Zhang; Shuai Du; Mixia Zhang

    2011-01-01

    Berberine, a major constituent of Coptidis rhizoma, exhibits neural protective effects. The present study analyzed the potential protective effect of berberine against amyloid G-induced cytotoxicity in rat cerebral cortical neurons. Alzheimer's disease cell models were treated with 0.5 and 2 μmol/Lberberine for 36 hours to inhibit amyloid G-induced toxicity. Methyl thiazolyl tetrazolium assay and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining results showed that berberine significantly increased cell viability and reduced cell apoptosis in primary cultured rat cortical neurons. In addition, western blot analysis revealed a protective effect of berberine against amyloid β-induced toxicity in cultured cortical neurons, which coincided with significantly decreased abnormal up-regulation of activated caspase-3. These results showed that berberine exhibited a protective effect against amyloid 13-induced cytotoxicity in cultured rat cortical neurons.

  18. Cortical stimulation and tooth pulp evoked potentials in rats: a model of direct anti-nociception.

    Science.gov (United States)

    Rusina, Robert; Barek, Stephane; Vaculin, Simon; Azérad, Jean; Rokyta, Richard

    2010-01-01

    While the effect of cortex stimulation on pain control is widely accepted, its physiological basis remains poorly understood. We chose an animal model of pain to study the influence of sensorimotor cortex stimulation on tooth pulp stimulation evoked potentials (TPEPs). Fifteen awake rats implanted with tooth pulp, cerebral cortex, and digastric muscle electrodes were divided into three groups, receiving 60 Hz, 40 Hz and no cortical stimulation, respectively. TPEPs were recorded before, one, three and five hours after continuous stimulation. We observed an inverse relationship between TPEP amplitude and latency with increasing tooth pulp stimulation. The amplitudes of the early components of TPEPs increased and their latency decreased with increasing tooth pulp stimulation intensity. Cortical stimulation decreased the amplitude of TPEPs; however, neither the latencies of TPEPs nor the jaw-opening reflex were changed after cortical stimulation. The decrease in amplitude of TPEPs after cortical stimulation may reflect its anti-nociceptive effect.

  19. Evaluating mandibular cortical index quantitatively.

    Science.gov (United States)

    Yasar, Fusun; Akgunlu, Faruk

    2008-10-01

    The aim was to assess whether Fractal Dimension and Lacunarity analysis can discriminate patients having different mandibular cortical shape. Panoramic radiographs of 52 patients were evaluated for mandibular cortical index. Weighted Kappa between the observations were varying between 0.718-0.805. These radiographs were scanned and converted to binary images. Fractal Dimension and Lacunarity were calculated from the regions where best represents the cortical morphology. It was found that there were statistically significant difference between the Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 1 and Cl 2 (Fractal Dimension P:0.000; Lacunarity P:0.003); and Cl 1 and Cl 3 cortical morphology (Fractal Dimension P:0.008; Lacunarity P:0.001); but there was no statistically significant difference between Fractal Dimension and Lacunarity of radiographs which were classified as having Cl 2 and Cl 3 cortical morphology (Fractal Dimension P:1.000; Lacunarity P:0.758). FD and L can differentiate Cl 1 mandibular cortical shape from both Cl 2 and Cl 3 mandibular cortical shape but cannot differentiate Cl 2 from Cl 3 mandibular cortical shape on panoramic radiographs.

  20. Cortico-cortical communication dynamics

    Directory of Open Access Journals (Sweden)

    Per E Roland

    2014-05-01

    Full Text Available IIn principle, cortico-cortical communication dynamics is simple: neurons in one cortical area communicate by sending action potentials that release glutamate and excite their target neurons in other cortical areas. In practice, knowledge about cortico-cortical communication dynamics is minute. One reason is that no current technique can capture the fast spatio-temporal cortico-cortical evolution of action potential transmission and membrane conductances with sufficient spatial resolution. A combination of optogenetics and monosynaptic tracing with virus can reveal the spatio-temporal cortico-cortical dynamics of specific neurons and their targets, but does not reveal how the dynamics evolves under natural conditions. Spontaneous ongoing action potentials also spread across cortical areas and are difficult to separate from structured evoked and intrinsic brain activity such as thinking. At a certain state of evolution, the dynamics may engage larger populations of neurons to drive the brain to decisions, percepts and behaviors. For example, successfully evolving dynamics to sensory transients can appear at the mesoscopic scale revealing how the transient is perceived. As a consequence of these methodological and conceptual difficulties, studies in this field comprise a wide range of computational models, large-scale measurements (e.g., by MEG, EEG, and a combination of invasive measurements in animal experiments. Further obstacles and challenges of studying cortico-cortical communication dynamics are outlined in this critical review.

  1. A key mechanism underlying sensory experience-dependent maturation of neocortical GABAergic circuits in vivo

    OpenAIRE

    Jiao, Yuanyuan; Zhang, Zhi; Zhang, Chunzhao; Wang, Xinjun; Sakata, Kazuko; Lu, Bai; Sun, Qian-Quan

    2011-01-01

    Mechanisms underlying experience-dependent refinement of cortical connections, especially GABAergic inhibitory circuits, are unknown. By using a line of mutant mice that lack activity-dependent BDNF expression (bdnf-KIV), we show that experience regulation of cortical GABAergic network is mediated by activity-driven BDNF expression. Levels of endogenous BDNF protein in the barrel cortex are strongly regulated by sensory inputs from whiskers. There is a severe alteration of excitation and inhi...

  2. Visual cortical areas of the mouse: comparison of parcellation and network structure with primates.

    Science.gov (United States)

    Laramée, Marie-Eve; Boire, Denis

    2014-01-01

    Brains have evolved to optimize sensory processing. In primates, complex cognitive tasks must be executed and evolution led to the development of large brains with many cortical areas. Rodents do not accomplish cognitive tasks of the same level of complexity as primates and remain with small brains both in relative and absolute terms. But is a small brain necessarily a simple brain? In this review, several aspects of the visual cortical networks have been compared between rodents and primates. The visual system has been used as a model to evaluate the level of complexity of the cortical circuits at the anatomical and functional levels. The evolutionary constraints are first presented in order to appreciate the rules for the development of the brain and its underlying circuits. The organization of sensory pathways, with their parallel and cross-modal circuits, is also examined. Other features of brain networks, often considered as imposing constraints on the development of underlying circuitry, are also discussed and their effect on the complexity of the mouse and primate brain are inspected. In this review, we discuss the common features of cortical circuits in mice and primates and see how these can be useful in understanding visual processing in these animals.

  3. Approximate circuits for increased reliability

    Energy Technology Data Exchange (ETDEWEB)

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-08-18

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  4. Approximate circuits for increased reliability

    Energy Technology Data Exchange (ETDEWEB)

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-12-22

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  5. Cortical and spinal assessment

    DEFF Research Database (Denmark)

    Fischer, I W; Gram, Mikkel; Hansen, T M

    2017-01-01

    BACKGROUND: Standardized objective methods to assess the analgesic effects of opioids, enable identification of underlying mechanisms of drug actions in the central nervous system. Opioids may exert their effect on both cortical and spinal levels. In this study actions of morphine at both levels...... subjects was included in the data analysis. There was no change in the activity in resting EEG (P>0.05) after morphine administration as compared to placebo. During cold pressor stimulation, morphine significantly lowered the relative activity in the delta (1-4Hz) band (P=0.03) and increased the activity...... morphine administration (P>0.05). CONCLUSIONS: Cold pressor EEG and the nociceptive reflex were more sensitive to morphine analgesia than resting EEG and can be used as standardized objective methods to assess opioid effects. However, no correlation between the analgesic effect of morphine on the spinal...

  6. Hiperostosis cortical infantil

    OpenAIRE

    Salvador Javier Santos Medina; Orelvis Pérez Duerto

    2015-01-01

    La enfermedad de Caffey, o hiperostosis cortical infantil, es una rara enfermedad ósea autolimitada, que aparece de preferencia en lactantes con signos inespecíficos sistémicos; el más relevante es la reacción subperióstica e hiperostosis en varios huesos del cuerpo, con predilección en el 75-80 % de los casos por la mandíbula. Su pronóstico es bueno, la mayoría no deja secuelas. El propósito del presente trabajo es describir las características clínicas, presentes en un lactante de cinco mes...

  7. Progressive posterior cortical dysfunction

    Directory of Open Access Journals (Sweden)

    Fábio Henrique de Gobbi Porto

    Full Text Available Abstract Progressive posterior cortical dysfunction (PPCD is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal and ventral (occipito-temporal pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction, complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

  8. Cortical plasticity and rehabilitation.

    Science.gov (United States)

    Moucha, Raluca; Kilgard, Michael P

    2006-01-01

    The brain is constantly adapting to environmental and endogenous changes (including injury) that occur at every stage of life. The mechanisms that regulate neural plasticity have been refined over millions of years. Motivation and sensory experience directly shape the rewiring that makes learning and neurological recovery possible. Guiding neural reorganization in a manner that facilitates recovery of function is a primary goal of neurological rehabilitation. As the rules that govern neural plasticity become better understood, it will be possible to manipulate the sensory and motor experience of patients to induce specific forms of plasticity. This review summarizes our current knowledge regarding factors that regulate cortical plasticity, illustrates specific forms of reorganization induced by control of each factor, and suggests how to exploit these factors for clinical benefit.

  9. CT findings of cerebral paragonimiasis in the chronic state

    Energy Technology Data Exchange (ETDEWEB)

    Udaka, F.; Okuda, B.; Tsuji, T.; Kameyama, M.; Okada, M.

    1988-02-01

    The CT findings in 5 patients with cerebral paragonimiasis in the chronic state are presented. The findings were: 1) multiple, densely calcified areas with a variety of round or nodular shapes in the brain, 2) a large low density area surrounding or connecting with the calcified areas, and 3) cortical atrophy and ventricular dilatation. The relation between the CT findings and the previously reported plain skull X-ray findings or neuropathological findings are discussed.

  10. CT findings of cerebral paragonimiasis in the chronic state.

    Science.gov (United States)

    Udaka, F; Okuda, B; Okada, M; Tsuji, T; Kameyama, M

    1988-01-01

    The CT findings in 5 patients with cerebral paragonimiasis in the chronic state are presented. The findings were: 1) multiple, densely calcified areas with a variety of round or nodular shapes in the brain, 2) a large low density area surrounding or connecting with the calcified areas, and 3) cortical atrophy and ventricular dilatation. The relation between the CT findings and the previously reported plain skull X-ray findings or neuropathological findings are discussed.

  11. Cell types, circuits, and receptive fields in the mouse visual cortex.

    Science.gov (United States)

    Niell, Cristopher M

    2015-07-08

    Over the past decade, the mouse has emerged as an important model system for studying cortical function, owing to the advent of powerful tools that can record and manipulate neural activity in intact neural circuits. This advance has been particularly prominent in the visual cortex, where studies in the mouse have begun to bridge the gap between cortical structure and function, allowing investigators to determine the circuits that underlie specific visual computations. This review describes the advances in our understanding of the mouse visual cortex, including neural coding, the role of different cell types, and links between vision and behavior, and discusses how recent findings and new approaches can guide future studies.

  12. The Impact of Structural Heterogeneity on Excitation-Inhibition Balance in Cortical Networks.

    Science.gov (United States)

    Landau, Itamar D; Egger, Robert; Dercksen, Vincent J; Oberlaender, Marcel; Sompolinsky, Haim

    2016-12-07

    Models of cortical dynamics often assume a homogeneous connectivity structure. However, we show that heterogeneous input connectivity can prevent the dynamic balance between excitation and inhibition, a hallmark of cortical dynamics, and yield unrealistically sparse and temporally regular firing. Anatomically based estimates of the connectivity of layer 4 (L4) rat barrel cortex and numerical simulations of this circuit indicate that the local network possesses substantial heterogeneity in input connectivity, sufficient to disrupt excitation-inhibition balance. We show that homeostatic plasticity in inhibitory synapses can align the functional connectivity to compensate for structural heterogeneity. Alternatively, spike-frequency adaptation can give rise to a novel state in which local firing rates adjust dynamically so that adaptation currents and synaptic inputs are balanced. This theory is supported by simulations of L4 barrel cortex during spontaneous and stimulus-evoked conditions. Our study shows how synaptic and cellular mechanisms yield fluctuation-driven dynamics despite structural heterogeneity in cortical circuits.

  13. Plasmonic Nanoguides and Circuits

    CERN Document Server

    Bozhevolnyi, Sergey

    2008-01-01

    Modern communication systems dealing with huge amounts of data at ever increasing speed try to utilize the best aspects of electronic and optical circuits. Electronic circuits are tiny but their operation speed is limited, whereas optical circuits are extremely fast but their sizes are limited by diffraction. Waveguide components utilizing surface plasmon (SP) modes were found to combine the huge optical bandwidth and compactness of electronics, and plasmonics thereby began to be considered as the next chip-scale technology. In this book, the authors concentrate on the SP waveguide configurati

  14. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Optoelectronics Circuits Manual covers the basic principles and characteristics of the best known types of optoelectronic