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Sample records for superior parietal cortices

  1. [Parietal Cortices and Body Information].

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    Naito, Eiichi; Amemiya, Kaoru; Morita, Tomoyo

    2016-11-01

    Proprioceptive signals originating from skeletal muscles and joints contribute to the formation of both the human body schema and the body image. In this chapter, we introduce various types of bodily illusions that are elicited by proprioceptive inputs, and we discuss distinct functions implemented by different parietal cortices. First, we illustrate the primary importance of the motor network in the processing of proprioceptive (kinesthetic) signals originating from muscle spindles. Next, we argue that the right inferior parietal cortex, in concert with the inferior frontal cortex (both regions connected by the inferior branch of the superior longitudinal fasciculus-SLF III), may be involved in the conscious experience of body image. Further, we hypothesize other functions of distinct parietal regions: the association between internal hand motor representation with external object representation in the left inferior parietal cortex, visuo-kinesthetic processing in the bilateral posterior parietal cortices, and the integration of somatic signals from different body parts in the higher-order somatosensory parietal cortices. Our results indicate that a distinct parietal region, in concert with its anatomically and functionally connected frontal regions, probably plays specialized roles in the processing of body-related information.

  2. Cerebello-thalamo-cortical projections to the posterior parietal cortex in the macaque monkey.

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    Amino, Y; Kyuhou, S; Matsuzaki, R; Gemba, H

    2001-08-17

    The cerebello-thalamo-posterior parietal cortical projections were investigated electrophysiologically and morphologically in macaque monkeys. In anesthetized monkeys, electrical stimulation of every cerebellar nucleus evoked marked surface-positive, depth-negative (s-P, d-N) cortical field potentials in the superior parietal lobule and the cortical bank of the intraparietal sulcus, but no responses in the inferior parietal lobule. Tract-tracing experiments combining the anterograde method with the retrograde one indicated that the interposed and lateral cerebellar nuclei projected to the posterior parietal cortex mainly through the nucleus ventral lateralis caudalis of the thalamus. The significance of the projections is discussed in connection with cognitive functions.

  3. Neural correlates of superior intelligence: stronger recruitment of posterior parietal cortex.

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    Lee, Kun Ho; Choi, Yu Yong; Gray, Jeremy R; Cho, Sun Hee; Chae, Jeong-Ho; Lee, Seungheun; Kim, Kyungjin

    2006-01-15

    General intelligence (g) is a common factor in diverse cognitive abilities and a major influence on life outcomes. Neuroimaging studies in adults suggest that the lateral prefrontal and parietal cortices play a crucial role in related cognitive activities including fluid reasoning, the control of attention, and working memory. Here, we investigated the neural bases for intellectual giftedness (superior-g) in adolescents, using fMRI. The participants consisted of a superior-g group (n = 18, mean RAPM = 33.9 +/- 0.8, >99%) from the national academy for gifted adolescents and the control group (n = 18, mean RAPM = 22.8 +/- 1.6, 60%) from local high schools in Korea (mean age = 16.5 +/- 0.8). fMRI data were acquired while they performed two reasoning tasks with high and low g-loadings. In both groups, the high g-loaded tasks specifically increased regional activity in the bilateral fronto-parietal network including the lateral prefrontal, anterior cingulate, and posterior parietal cortices. However, the regional activations of the superior-g group were significantly stronger than those of the control group, especially in the posterior parietal cortex. Moreover, regression analysis revealed that activity of the superior and intraparietal cortices (BA 7/40) strongly covaried with individual differences in g (r = 0.71 to 0.81). A correlated vectors analysis implicated bilateral posterior parietal areas in g. These results suggest that superior-g may not be due to the recruitment of additional brain regions but to the functional facilitation of the fronto-parietal network particularly driven by the posterior parietal activation.

  4. Thalamo-cortical projections to the posterior parietal cortex in the monkey.

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    Matsuzaki, Ryuichi; Kyuhou, Shin-ichi; Matsuura-Nakao, Kazuko; Gemba, Hisae

    2004-01-23

    Thalamo-cortical projections to the posterior parietal cortex (PPC) were investigated electrophysiologically in the monkey. Cortical field potentials evoked by the thalamic stimulation were recorded with electrodes chronically implanted on the cortical surface and at a 2.0-3.0 mm cortical depth in the PPC. The stimulation of the nucleus lateralis posterior (LP), nucleus ventralis posterior lateralis pars caudalis (VPLc), and nucleus pulvinaris lateralis (Pul.l) and medialis (Pul.m) induced surface-negative, depth-positive potentials in the PPC. The LP and VPLc projected mainly to the superior parietal lobule (SPL) and the anterior bank of the intraparietal sulcus (IPS), and the Pul.m mainly to the inferior parietal lobule (IPL) and the posterior bank of the IPS. The Pul.l had projections to all of the SPL, the IPL and both the banks. The significance of the projections is discussed in connection with motor functions.

  5. Cortical networks for visual reaching: physiological and anatomical organization of frontal and parietal lobe arm regions.

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    Johnson, P B; Ferraina, S; Bianchi, L; Caminiti, R

    1996-01-01

    The functional and structural properties of the dorsolateral frontal lobe and posterior parietal proximal arm representations were studied in macaque monkeys. Physiological mapping of primary motor (MI), dorsal premotor (PMd), and posterior parietal (area 5) cortices was performed in behaving monkeys trained in an instructed-delay reaching task. The parietofrontal corticocortical connectivities of these same areas were subsequently examined anatomically by means of retrograde tracing techniques. Signal-, set-, movement-, and position-related directional neuronal activities were distributed nonuniformly within the task-related areas in both frontal and parietal cortices. Within the frontal lobe, moving caudally from PMd to the MI, the activity that signals for the visuo-spatial events leading to target localization decreased, while the activity more directly linked to movement generation increased. Physiological recordings in the superior parietal lobule revealed a gradient-like distribution of functional properties similar to that observed in the frontal lobe. Signal- and set-related activities were encountered more frequently in the intermediate and ventral part of the medial bank of the intraparietal sulcus (IPS), in area MIP. Movement-and position-related activities were distributed more uniformly within the superior parietal lobule (SPL), in both dorsal area 5 and in MIP. Frontal and parietal regions sharing similar functional properties were preferentially connected through their association pathways. As a result of this study, area MIP, and possibly areas MDP and 7m as well, emerge as the parietal nodes by which visual information may be relayed to the frontal lobe arm region. These parietal and frontal areas, along with their association connections, represent a potential cortical network for visual reaching. The architecture of this network is ideal for coding reaching as the result of a combination between visual and somatic information.

  6. Sustained attention is associated with right superior longitudinal fasciculus and superior parietal white matter microstructure in children.

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    Klarborg, Brith; Skak Madsen, Kathrine; Vestergaard, Martin; Skimminge, Arnold; Jernigan, Terry L; Baaré, William F C

    2013-12-01

    Sustained attention develops during childhood and has been linked to the right fronto-parietal cortices in functional imaging studies; however, less is known about its relation to white matter (WM) characteristics. Here we investigated whether the microstructure of the WM underlying and connecting the right fronto-parietal cortices was associated with sustained attention performance in a group of 76 typically developing children aged 7-13 years. Sustained attention was assessed using a rapid visual information processing paradigm. The two behavioral measures of interest were the sensitivity index d' and the coefficient of variation in reaction times (RTCV ). Diffusion-weighted imaging was performed. Mean fractional anisotropy (FA) was extracted from the WM underlying right dorsolateral prefrontal (DLPFC) and parietal cortex (PC), and the right superior longitudinal fasciculus (SLF), as well as equivalent anatomical regions-of-interest (ROIs) in the left hemisphere and mean global WM FA. When analyzed collectively, right hemisphere ROIs FA was significantly associated with d' independently of age. Follow-up analyses revealed that only FA of right SLF and the superior part of the right PC contributed significantly to this association. RTCV was significantly associated with right superior PC FA, but not with right SLF FA. Observed associations remained significant after controlling for FA of equivalent left hemisphere ROIs or global mean FA. In conclusion, better sustained attention performance was associated with higher FA of WM in regions connecting right frontal and parietal cortices. Further studies are needed to clarify to which extent these associations are driven by maturational processes, stable characteristics and/or experience.

  7. Age-related temporal and parietal cortical thinning in autism spectrum disorders.

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    Wallace, Gregory L; Dankner, Nathan; Kenworthy, Lauren; Giedd, Jay N; Martin, Alex

    2010-12-01

    Studies of head size and brain volume in autism spectrum disorders have suggested that early cortical overgrowth may be followed by prematurely arrested growth. However, the few investigations quantifying cortical thickness have yielded inconsistent results, probably due to variable ages and/or small sample sizes. We assessed differences in cortical thickness between high-functioning adolescent and young adult males with autism spectrum disorders (n = 41) and matched typically developing males (n = 40). We hypothesized thinner cortex, particularly in frontal, parietal and temporal regions, for individuals with autism spectrum disorders in comparison with typically developing controls. Furthermore, we expected to find an age × diagnosis interaction: with increasing age, more pronounced cortical thinning would be observed in autism spectrum disorders than typically developing participants. T(1)-weighted magnetization prepared rapid gradient echo 3 T magnetic resonance imaging scans were acquired from high-functioning males with autism spectrum disorders and from typically developing males matched group-wise on age (range 12-24 years), intelligence quotient (≥ 85) and handedness. Both gyral-level and vertex-based analyses revealed significantly thinner cortex in the autism spectrum disorders group that was located predominantly in left temporal and parietal regions (i.e. the superior temporal sulcus, inferior temporal, postcentral/superior parietal and supramarginal gyri). These findings remained largely unchanged after controlling for intelligence quotient and after accounting for psychotropic medication usage and comorbid psychopathology. Furthermore, a significant age × diagnosis interaction was found in the left fusiform/inferior temporal cortex: participants with autism spectrum disorders had thinner cortex in this region with increasing age to a greater degree than did typically developing participants. Follow-up within group comparisons revealed significant

  8. Central and peripheral components of writing critically depend on a defined area of the dominant superior parietal gyrus.

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    Magrassi, Lorenzo; Bongetta, Daniele; Bianchini, Simonetta; Berardesca, Marta; Arienta, Cesare

    2010-07-30

    Classical neuropsychological models of writing separate central (linguistic) processes common to oral spelling, writing and typing from peripheral (motor) processes that are modality specific. Damage to the left superior parietal gyrus, an area of the cortex involved in peripheral processes specific to handwriting, should generate distorted graphemes but not misspelled words, while damage to other areas of the cortex like the frontal lobe should produce alterations in written and oral spelling without distorted graphemes. We describe the clinical and neuropsychological features of a patient with combined agraphia for handwriting and typewriting bearing a small glioblastoma in the left parietal lobe. His agraphia resolved after antiedema therapy and we tested by bipolar cortical stimulation his handwriting abilities during an awake neurosurgical procedure. We found that we could reversibly re-induce the same defects of writing by stimulating during surgery a limited area of the superior parietal gyrus in the same patient and in an independent patient that was never agraphic before the operation. In those patients stimulation caused spelling errors, poorly formed letters and in some cases a complete cessation of writing with minimal or no effects on oral spelling. Our results suggest that stimulating a specific area in the superior parietal gyrus we can generate different patterns of agraphia. Moreover, our findings also suggest that some of the central processes specific for typing and handwriting converge with motor processes at least in the limited portion of the superior parietal gyrus we mapped in our patients.

  9. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

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    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  10. Dissociation of Subtraction and Multiplication in the Right Parietal Cortex: Evidence from Intraoperative Cortical Electrostimulation

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    Yu, Xiaodan; Chen, Chuansheng; Pu, Song; Wu, Chenxing; Li, Yongnian; Jiang, Tao; Zhou, Xinlin

    2011-01-01

    Previous research has consistently shown that the left parietal cortex is critical for numerical processing, but the role of the right parietal lobe has been much less clear. This study used the intraoperative cortical electrical stimulation approach to investigate neural dissociation in the right parietal cortex for subtraction and…

  11. Somatosensory-motor adaptation of orofacial actions in posterior parietal and ventral premotor cortices.

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    Krystyna Grabski

    Full Text Available Recent studies have provided evidence for sensory-motor adaptive changes and action goal coding of visually guided manual action in premotor and posterior parietal cortices. To extend these results to orofacial actions, devoid of auditory and visual feedback, we used a repetition suppression paradigm while measuring neural activity with functional magnetic resonance imaging during repeated intransitive and silent lip, jaw and tongue movements. In the motor domain, this paradigm refers to decreased activity in specific neural populations due to repeated motor acts and has been proposed to reflect sensory-motor adaptation. Orofacial movements activated a set of largely overlapping, common brain areas forming a core neural network classically involved in orofacial motor control. Crucially, suppressed neural responses during repeated orofacial actions were specifically observed in the left ventral premotor cortex, the intraparietal sulcus, the inferior parietal lobule and the superior parietal lobule. Since no visual and auditory feedback were provided during orofacial actions, these results suggest somatosensory-motor adaptive control of intransitive and silent orofacial actions in these premotor and parietal regions.

  12. Auditory cortical delta-entrainment interacts with oscillatory power in multiple fronto-parietal networks.

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    Keitel, Anne; Ince, Robin A A; Gross, Joachim; Kayser, Christoph

    2017-02-15

    The timing of slow auditory cortical activity aligns to the rhythmic fluctuations in speech. This entrainment is considered to be a marker of the prosodic and syllabic encoding of speech, and has been shown to correlate with intelligibility. Yet, whether and how auditory cortical entrainment is influenced by the activity in other speech-relevant areas remains unknown. Using source-localized MEG data, we quantified the dependency of auditory entrainment on the state of oscillatory activity in fronto-parietal regions. We found that delta band entrainment interacted with the oscillatory activity in three distinct networks. First, entrainment in the left anterior superior temporal gyrus (STG) was modulated by beta power in orbitofrontal areas, possibly reflecting predictive top-down modulations of auditory encoding. Second, entrainment in the left Heschl's Gyrus and anterior STG was dependent on alpha power in central areas, in line with the importance of motor structures for phonological analysis. And third, entrainment in the right posterior STG modulated theta power in parietal areas, consistent with the engagement of semantic memory. These results illustrate the topographical network interactions of auditory delta entrainment and reveal distinct cross-frequency mechanisms by which entrainment can interact with different cognitive processes underlying speech perception.

  13. Distinct contributions by frontal and parietal cortices support working memory.

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    Mackey, Wayne E; Curtis, Clayton E

    2017-07-21

    Although subregions of frontal and parietal cortex both contribute and coordinate to support working memory (WM) functions, their distinct contributions remain elusive. Here, we demonstrate that perturbations to topographically organized human frontal and parietal cortex during WM maintenance cause distinct but systematic distortions in WM. The nature of these distortions supports theories positing that parietal cortex mainly codes for retrospective sensory information, while frontal cortex codes for prospective action.

  14. Sustained attention is associated with right superior longitudinal fasciculus and superior parietal white matter microstructure in children

    DEFF Research Database (Denmark)

    Klarborg, Brith; Skak Madsen, Kathrine; Vestergaard, Martin

    2013-01-01

    the right fronto-parietal cortices was associated with sustained attention performance in a group of 76 typically developing children aged 7-13 years. Sustained attention was assessed using a rapid visual information processing paradigm. The two behavioral measures of interest were the sensitivity index d......Sustained attention develops during childhood and has been linked to the right fronto-parietal cortices in functional imaging studies; however, less is known about its relation to white matter (WM) characteristics. Here we investigated whether the microstructure of the WM underlying and connecting...

  15. Gelastic seizures and fever originating from a parietal cortical dysplasia

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    Sana Chaouki

    2013-01-01

    Full Text Available Gelastic seizures (GS is an uncommon seizure type characterized by sudden inappropriate attacks of uncontrolled and unmotivated laugh and its diagnostic criteria were elaborated by Gascon. These criteria included stereotypical recurrence of laugh, which is unjustified by the context, associated signs compatible with seizure, and ictal or interictal abnormalities. GS can be cryptogenic or symptomatic of a variety of cerebral lesions, the most common being hypothalamic hamartoma. However, GS associated with other types of cerebral lesions are exceedingly rare. The physiopathologic mechanisms of this type of seizure are still undefined. Two reports have described a non-lesional GS arising from a parietal focus. In this paper, we report the first case of lesional GS associated to the parietal area of the brain in a child and this case has associated fever that is likely an ictal symptom.

  16. Decoding the superior parietal lobule connections of the superior longitudinal fasciculus/arcuate fasciculus in the human brain.

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    Kamali, A; Sair, H I; Radmanesh, A; Hasan, K M

    2014-09-26

    The temporo-parietal (TP) white matter connections between the inferior parietal lobule and superior temporal gyrus as part of the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) or middle longitudinal fasciculus (MdLF) have been studied in prior diffusion tensor tractography (DTT) studies. However, few studies have been focusing on the higher TP connections of the superior parietal lobule with the temporal lobe. These higher TP connections have been shown to have a role in core processes such as attention, memory, emotions, and language. Our most recent study, for the first time, hinted to the possibility of a long white matter connection interconnecting the superior parietal lobule (SPL) with the posterior temporal lobe in human brain which we call the SLF/AF TP-SPL and for a shorter abbreviation, the TP-SPL. We decided to further investigate this white matter connection using fiber assignment by continuous tracking deterministic tractography and high spatial resolution diffusion tensor imaging on 3T. Five healthy right-handed men (age range 24-37 years) were studied. We delineated the SPL connections of the SLF/AF TP bilaterally in five normal adult human brains. Using a high resolution DTT technique, we demonstrate for the first time, the trajectory of a long fiber bundle connectivity between the SPL and posterior temporal lobe, called the SLF/AF TP-SPL (or the TP-SPL), bilaterally in five healthy adult human brains. We also demonstrate the trajectory of the vertically oriented posterior TP connections, interconnecting the inferior parietal lobule (IPL) with the posterior temporal lobe (TP-IPL) in relation to the TP-SPL, arcuate fasciculus and other major language pathways. In the current study, for the first time, we categorized the TP connections into the anterior and posterior connectivity groups and subcategorized each one into the SPL or IPL connections. Published by Elsevier Ltd.

  17. Left superior parietal cortex involvement in writing: integrating fMRI with lesion evidence.

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    Menon, V; Desmond, J E

    2001-10-01

    Writing is a uniquely human skill that we utilize nearly everyday. Lesion studies in patients with Gerstmann's syndrome have pointed to the parietal cortex as being critical for writing. Very little information is, however, available about the precise anatomical location of brain regions subserving writing in normal healthy individuals. In this study, we used functional magnetic resonance imaging (fMRI) to investigate parietal lobe function during writing to dictation. Significant clusters of activation were observed in left superior parietal lobe (SPL) and the dorsal aspects of the inferior parietal cortex (IPC) bordering the SPL. Localized clusters of activation were also observed in the left premotor cortex, sensorimotor cortex and supplementary motor area. No activation cluster was observed in the right hemisphere. These results clearly indicate that writing appears to be primarily organized in the language-dominant hemisphere. Further analysis revealed that within the parietal cortex, activation was significantly greater in the left SPL, compared to left IPC. Together with lesion studies, findings from the present study provide further evidence for the essential role of the left SPL in writing. Deficits to the precise left hemisphere parietal cortex regions identified in the present study may specifically underlie disorders of writing observed in Gerstmann's syndrome and apractic agraphia.

  18. Human middle longitudinal fascicle: Segregation and behavioral-clinical implications of two distinct fiber connections linking temporal pole and superior temporal gyrus with the angular gyrus or superior parietal lobule using multi-tensor tractography

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    Makris, N.; Preti, M.G.; Wassermann, D.; Rathi, Y.; Papadimitriou, G. M.; Yergatian, C.; Dickerson, B. C.; Shenton, M. E.; Kubicki, M.

    2013-01-01

    The middle longitudinal fascicle (MdLF) is a major fiber connection running principally between the superior temporal gyrus and the parietal lobe, neocortical regions of great biological and clinical interest. Although one of the most prominent cerebral association fiber tracts it has only recently been discovered in humans. In this high angular resolution diffusion imaging (HARDI) MRI study, we delineated the two major fiber connections of the human MdLF, by examining morphology, topography, cortical connections, biophysical measures, volume and length in seventy-four brains. These two fiber connections course together through the dorsal temporal pole and the superior temporal gyrus maintaining a characteristic topographic relationship in the mediolateral and ventrodorsal dimensions. As these pathways course towards the parietal lobe, they split to form separate fiber pathways, one following a ventrolateral trajectory and connecting with the angular gyrus and the other following a dorsomedial route and connecting with the superior parietal lobule. Based on the functions of their cortical affiliations, we suggest that the superior temporal-angular connection of the MdLF, i.e., STG(MdLF)AG plays a role in language and attention, whereas the superior temporal-superior parietal connection of the MdLF, i.e., STG(MdLF)SPL is involved in visuospatial and integrative audiovisual functions. Furthermore, the MdLF may have clinical implications in neurodegenerative disorders such as primary progressive aphasia, frontotemporal dementia, posterior cortical atrophy, corticobulbar degeneration and Alzheimer’s disease as well as attention-deficit/hyperactivity disorder and schizophrenia. PMID:23686576

  19. Frontal and Parietal Cortices Show Different Spatiotemporal Dynamics across Problem-solving Stages.

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    Tschentscher, Nadja; Hauk, Olaf

    2016-08-01

    Arithmetic problem-solving can be conceptualized as a multistage process ranging from task encoding over rule and strategy selection to step-wise task execution. Previous fMRI research suggested a frontal-parietal network involved in the execution of complex numerical and nonnumerical tasks, but evidence is lacking on the particular contributions of frontal and parietal cortices across time. In an arithmetic task paradigm, we evaluated individual participants' "retrieval" and "multistep procedural" strategies on a trial-by-trial basis and contrasted those in time-resolved analyses using combined EEG and MEG. Retrieval strategies relied on direct retrieval of arithmetic facts (e.g., 2 + 3 = 5). Procedural strategies required multiple solution steps (e.g., 12 + 23 = 12 + 20 + 3 or 23 + 10 + 2). Evoked source analyses revealed independent activation dynamics within the first second of problem-solving in brain areas previously described as one network, such as the frontal-parietal cognitive control network: The right frontal cortex showed earliest effects of strategy selection for multistep procedural strategies around 300 msec, before parietal cortex activated around 700 msec. In time-frequency source power analyses, memory retrieval and multistep procedural strategies were differentially reflected in theta, alpha, and beta frequencies: Stronger beta and alpha desynchronizations emerged for procedural strategies in right frontal, parietal, and temporal regions as function of executive demands. Arithmetic fact retrieval was reflected in right prefrontal increases in theta power. Our results demonstrate differential brain dynamics within frontal-parietal networks across the time course of a problem-solving process, and analyses of different frequency bands allowed us to disentangle cortical regions supporting the underlying memory and executive functions.

  20. Laminar thickness alterations in the fronto-parietal cortical mantle of patients with attention-deficit/hyperactivity disorder.

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    Elseline Hoekzema

    Full Text Available Although Attention-Deficit/Hyperactivity Disorder (ADHD was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43 and without ADHD (n = 41, as well as a group of adult neurotypical individuals (n = 31, adult patients with a history of stimulant treatment (n = 31 and medication-naïve adults with ADHD (n = 24. We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally. Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing.

  1. Laminar Thickness Alterations in the Fronto-Parietal Cortical Mantle of Patients with Attention-Deficit/Hyperactivity Disorder

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    Ramos-Quiroga, J. Antoni; Fernández, Vanesa Richarte; Picado, Marisol; Bosch, Rosa; Soliva, Juan Carlos; Rovira, Mariana; Vives, Yolanda; Bulbena, Antonio; Tobeña, Adolf; Casas, Miguel; Vilarroya, Oscar

    2012-01-01

    Although Attention-Deficit/Hyperactivity Disorder (ADHD) was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43) and without ADHD (n = 41), as well as a group of adult neurotypical individuals (n = 31), adult patients with a history of stimulant treatment (n = 31) and medication-naïve adults with ADHD (n = 24). We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally). Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing. PMID:23239964

  2. Visual processing of multiple elements in the dyslexic brain: evidence for a superior parietal dysfunction

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    Muriel Anne Lobier

    2014-07-01

    Full Text Available The visual attention (VA span deficit hypothesis of developmental dyslexia posits that impaired multiple element processing can be responsible for poor reading outcomes. In VA span impaired dyslexic children, poor performance on letter report tasks is associated with reduced parietal activations for multiple letter processing. While this hints towards a non-specific, attention-based dysfunction, it is still unclear whether reduced parietal activity generalizes to other types of stimuli. Furthermore, putative links between reduced parietal activity and reduced ventral occipito-temporal (vOT in dyslexia have yet to be explored. Using fMRI, we measured brain activity in 12 VA span impaired dyslexic adults and 12 adult skilled readers while they carried out a categorization task on single or multiple alphanumeric or non-alphanumeric characters. While healthy readers activated parietal areas more strongly for multiple than single element processing (right-sided for alphanumeric and bilateral for non-alphanumeric, similar stronger multiple element right parietal activations were absent for dyslexic participants. Contrasts between skilled and dyslexic readers revealed significantly reduced right superior parietal lobule (SPL activity for dyslexic readers regardless of stimuli type. Using a priori anatomically defined ROI, we showed that neural activity was reduced for dyslexic participants in both SPL and vOT bilaterally. Finally, we used multiple regressions to test whether SPL activity could predict vOT activity in each group. In the left hemisphere, SPL activity modulated vOT activity for both normal and dyslexic readers. In contrast, in the right hemisphere, SPL activity modulated vOT activity only for dyslexic readers. These results bring critical support to the visual attention interpretation of the VA Span deficit. In addition, they offer a new insight on how deficits in automatic vOT based word recognition could arise in developmental dyslexia.

  3. Atrophy of the Parietal Lobe in Preclinical Dementia

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    Jacobs, Heidi I. L.; Van Boxtel, Martin P. J.; Uylings, Harry B. M.; Gronenschild, Ed H. B. M.; Verhey, Frans R.; Jolles, Jelle

    2011-01-01

    Cortical grey matter atrophy patterns have been reported in healthy ageing and Alzheimer disease (AD), but less consistently in the parietal regions of the brain. We investigated cortical grey matter volume patterns in parietal areas. The grey matter of the somatosensory cortex, superior and inferior parietal lobule was measured in 75 older adults…

  4. Atrophy of the Parietal Lobe in Preclinical Dementia

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    Jacobs, Heidi I. L.; Van Boxtel, Martin P. J.; Uylings, Harry B. M.; Gronenschild, Ed H. B. M.; Verhey, Frans R.; Jolles, Jelle

    2011-01-01

    Cortical grey matter atrophy patterns have been reported in healthy ageing and Alzheimer disease (AD), but less consistently in the parietal regions of the brain. We investigated cortical grey matter volume patterns in parietal areas. The grey matter of the somatosensory cortex, superior and inferior parietal lobule was measured in 75 older adults…

  5. Cortical projections to the superior colliculus in tree shrews (Tupaia belangeri).

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    Baldwin, Mary K L; Wei, Haiyang; Reed, Jamie L; Bickford, Martha E; Petry, Heywood M; Kaas, Jon H

    2013-05-01

    The visuomotor functions of the superior colliculus depend not only on direct inputs from the retina, but also on inputs from neocortex. As mammals vary in the areal organization of neocortex, and in the organization of the number of visual and visuomotor areas, patterns of corticotectal projections vary. Primates in particular have a large number of visual areas projecting to the superior colliculus. As tree shrews are close relatives of primates, and they are also highly visual, we studied the distribution of cortical neurons projecting to the superior colliculus by injecting anatomical tracers into the colliculus. Since projections from visuotopically organized visual areas are expected to match the visuotopy of the superior colliculus, injections at different retinotopic locations in the superior colliculus provide information about the locations and organization of topographic areas in extrastriate cortex. Small injections in the superior colliculus labeled neurons in locations within areas 17 (V1) and 18 (V2) that are consistent with the known topography of these areas and the superior colliculus. In addition, the separate locations of clusters of labeled cells in temporal visual cortex provide evidence for five or more topographically organized areas. Injections that included deeper layers of the superior colliculus also labeled neurons in medial frontal cortex, likely in premotor cortex. Only occasional labeled neurons were observed in somatosensory or auditory cortex. Regardless of tracer injection location, we found that, unlike primates, a substantial projection to the superior colliculus from posterior parietal cortex is not a characteristic of tree shrews.

  6. The Neuroanatomical Basis for Posterior Superior Parietal Lobule Control Lateralization of Visuospatial Attention.

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    Wu, Yan; Wang, Jiaojian; Zhang, Yun; Zheng, Dingchen; Zhang, Jinfeng; Rong, Menglin; Wu, Huawang; Wang, Yinyan; Zhou, Ke; Jiang, Tianzi

    2016-01-01

    The right hemispheric dominance in visuospatial attention in human brain has been well established. Converging evidence has documented that ventral posterior parietal cortex (PPC) plays an important role in visuospatial attention. The role of dorsal PPC subregions, especially the superior parietal lobule (SPL) in visuospatial attention is still controversial. In the current study, we used repetitive transcranial magnetic stimulation (rTMS) and diffusion magnetic resonance imaging (MRI) techniques to test the role of posterior SPL in visuospatial attention and to investigate the potential neuroanatomical basis for right hemisphere dominance in visuospatial function. Transcranial magnetic stimulation (TMS) results unraveled that the right SPL predominantly mediated visuospatial attention compared to left SPL. Anatomical connections analyses between the posterior SPL and the intrahemispheric frontal subregions and the contralateral PPC revealed that right posterior SPL has stronger anatomical connections with the ipsilateral middle frontal gyrus (MFG), with the ipsilateral inferior frontal gyrus (IFG), and with contralateral PPC than that of the left posterior SPL. Furthermore, these asymmetric anatomical connections were closely related to behavioral performances. Our findings indicate that SPL plays a crucial role in regulating visuospatial attention, and dominance of visuospatial attention results from unbalanced interactions between the bilateral fronto-parietal networks and the interhemispheric parietal network.

  7. Self-face recognition shares brain regions active during proprioceptive illusion in the right inferior fronto-parietal superior longitudinal fasciculus III network.

    Science.gov (United States)

    Morita, Tomoyo; Saito, Daisuke N; Ban, Midori; Shimada, Koji; Okamoto, Yuko; Kosaka, Hirotaka; Okazawa, Hidehiko; Asada, Minoru; Naito, Eiichi

    2017-04-21

    Proprioception is somatic sensation that allows us to sense and recognize position, posture, and their changes in our body parts. It pertains directly to oneself and may contribute to bodily awareness. Likewise, one's face is a symbol of oneself, so that visual self-face recognition directly contributes to the awareness of self as distinct from others. Recently, we showed that right-hemispheric dominant activity in the inferior fronto-parietal cortices, which are connected by the inferior branch of the superior longitudinal fasciculus (SLF III), is associated with proprioceptive illusion (awareness), in concert with sensorimotor activity. Herein, we tested the hypothesis that visual self-face recognition shares brain regions active during proprioceptive illusion in the right inferior fronto-parietal SLF III network. We scanned brain activity using functional magnetic resonance imaging while twenty-two right-handed healthy adults performed two tasks. One was a proprioceptive illusion task, where blindfolded participants experienced a proprioceptive illusion of right hand movement. The other was a visual self-face recognition task, where the participants judged whether an observed face was their own. We examined whether the self-face recognition and the proprioceptive illusion commonly activated the inferior fronto-parietal cortices connected by the SLF III in a right-hemispheric dominant manner. Despite the difference in sensory modality and in the body parts involved in the two tasks, both tasks activated the right inferior fronto-parietal cortices, which are likely connected by the SLF III, in a right-side dominant manner. Here we discuss possible roles for right inferior fronto-parietal activity in bodily awareness and self-awareness. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  8. Cortical infarction of the right parietal lobe and neurogenic heart disease A report of three cases

    Institute of Scientific and Technical Information of China (English)

    Fang Li; Yujie Jia

    2012-01-01

    Three male patients were diagnosed with new cortical infarctions of the right parietal lobe on the basis of head magnetic resonance imaging; high-intensity signals indicating lesions in the right parietal lobe were noted on diffusion-weighted images at admission. Two of them presented with left hand weakness, and one exhibited left upper limb weakness. Treatment for improving blood supply to the brain was administered. One patient died suddenly because of ventricular fibrillation 3 days after admission. The other two patients had increased troponin levels and abnormal elec-trocardiograms, and were diagnosed with acute myocardial infarction half a month after admission. When lesions exist in field 7 of the parietal cortex (resulting in paralysis of the contralateral hand), the sympathetic center of the posterior lateral nucleus of the hypothalamus demonstrates compensatory excitement, which easily causes tachyarrhythmia and sudden death. Our experi-mental findings indicate that close electrocardiograph monitoring and cerebral infarction treatment should be standard procedures to predict and help prevent heart disease in patients with cerebral infarction in the right parietal lobe and left upper limb weakness as the main complaint.

  9. Cortical infarction of the right parietal lobe and neurogenic heart disease: A report of three cases.

    Science.gov (United States)

    Li, Fang; Jia, Yujie

    2012-04-25

    Three male patients were diagnosed with new cortical infarctions of the right parietal lobe on the basis of head magnetic resonance imaging; high-intensity signals indicating lesions in the right parietal lobe were noted on diffusion-weighted images at admission. Two of them presented with left hand weakness, and one exhibited left upper limb weakness. Treatment for improving blood supply to the brain was administered. One patient died suddenly because of ventricular fibrillation 3 days after admission. The other two patients had increased troponin levels and abnormal electrocardiograms, and were diagnosed with acute myocardial infarction half a month after admission. When lesions exist in field 7 of the parietal cortex (resulting in paralysis of the contralateral hand), the sympathetic center of the posterior lateral nucleus of the hypothalamus demonstrates compensatory excitement, which easily causes tachyarrhythmia and sudden death. Our experimental findings indicate that close electrocardiograph monitoring and cerebral infarction treatment should be standard procedures to predict and help prevent heart disease in patients with cerebral infarction in the right parietal lobe and left upper limb weakness as the main complaint.

  10. Differential roles for parietal and occipital cortices in visual working memory.

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    Daisuke Matsuyoshi

    Full Text Available Visual working memory (VWM is known as a highly capacity-limited cognitive system that can hold 3-4 items. Recent studies have demonstrated that activity in the intraparietal sulcus (IPS and occipital cortices correlates with the number of representations held in VWM. However, differences among those regions are poorly understood, particularly when task-irrelevant items are to be ignored. The present fMRI-based study investigated whether memory load-sensitive regions such as the IPS and occipital cortices respond differently to task-relevant information. Using a change detection task in which participants are required to remember pre-specified targets, here we show that while the IPS exhibited comparable responses to both targets and distractors, the dorsal occipital cortex manifested significantly weaker responses to an array containing distractors than to an array containing only targets, despite that the number of objects presented was the same for the two arrays. These results suggest that parietal and occipital cortices engage differently in distractor processing and that the dorsal occipital, rather than parietal, activity appears to reflect output of stimulus filtering and selection based on behavioral relevance.

  11. Optimized gamma synchronization enhances functional binding of fronto-parietal cortices in mathematically gifted adolescents during deductive reasoning

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    Li eZhang

    2014-06-01

    Full Text Available As enhanced fronto-parietal network has been suggested to support reasoning ability of math-gifted adolescents, the main goal of this EEG source analysis is to investigate the temporal binding of the gamma-band (30-60Hz synchronization between frontal and parietal cortices in adolescents with exceptional mathematical ability, including the functional connectivity of gamma neurocognitive network, the temporal dynamics of fronto-parietal network (phase-locking durations and network lability in time domain, and the self-organized criticality of synchronizing oscillation. Compared with the average-ability subjects, the math-gifted adolescents show a highly integrated fronto-parietal network due to distant gamma phase-locking oscillations, which is indicated by lower modularity of the global network topology, more connector bridges between the frontal and parietal cortices and less connector hubs in the sensorimotor cortex. The time-domain analysis finds that, while maintaining more stable phase dynamics of the fronto-parietal coupling, the math-gifted adolescents are characterized by more extensive fronto-parietal connection reconfiguration. The results from sample fitting in the power-law model further find that the phase-locking durations in the math-gifted brain abides by a wider interval of the power-law distribution. This phase-lock distribution mechanism could represent a relatively optimized pattern for the functional binding of frontal-parietal network, which underlies stable fronto-parietal connectivity and increases flexibility of timely network reconfiguration.

  12. Differential roles of the dorsal prefrontal and posterior parietal cortices in visual search: a TMS study.

    Science.gov (United States)

    Yan, Yulong; Wei, Rizhen; Zhang, Qian; Jin, Zhenlan; Li, Ling

    2016-07-25

    Although previous studies have shown that fronto-parietal attentional networks play a crucial role in bottom-up and top-down processes, the relative contribution of the frontal and parietal cortices to these processes remains elusive. Here we used transcranial magnetic stimulation (TMS) to interfere with the activity of the right dorsal prefrontal cortex (DLPFC) or the right posterior parietal cortex (PPC), immediately prior to the onset of the visual search display. Participants searched a target defined by color and orientation in "pop-out" or "search" condition. Repetitive TMS was applied to either the right DLPFC or the right PPC on different days. Performance was evaluated at baseline (no TMS), during TMS, and after TMS (Post-session). RTs were prolonged when TMS was applied over the DLPFC in the search, but not in the pop-out condition, relative to the baseline session. In comparison, TMS over the PPC prolonged RTs in the pop-out condition, and when the target appeared in the left visual field for the search condition. Taken together these findings provide evidence for a differential role of DLPFC and PPC in the visual search, indicating that DLPFC has a specific involvement in the "search" condition, while PPC is mainly involved in detecting "pop-out" targets.

  13. Functional Connectivity Between Superior Parietal Lobule and Primary Visual Cortex "at Rest" Predicts Visual Search Efficiency.

    Science.gov (United States)

    Bueichekú, Elisenda; Ventura-Campos, Noelia; Palomar-García, María-Ángeles; Miró-Padilla, Anna; Parcet, María-Antonia; Ávila, César

    2015-10-01

    Spatiotemporal activity that emerges spontaneously "at rest" has been proposed to reflect individual a priori biases in cognitive processing. This research focused on testing neurocognitive models of visual attention by studying the functional connectivity (FC) of the superior parietal lobule (SPL), given its central role in establishing priority maps during visual search tasks. Twenty-three human participants completed a functional magnetic resonance imaging session that featured a resting-state scan, followed by a visual search task based on the alphanumeric category effect. As expected, the behavioral results showed longer reaction times and more errors for the within-category (i.e., searching a target letter among letters) than the between-category search (i.e., searching a target letter among numbers). The within-category condition was related to greater activation of the superior and inferior parietal lobules, occipital cortex, inferior frontal cortex, dorsal anterior cingulate cortex, and the superior colliculus than the between-category search. The resting-state FC analysis of the SPL revealed a broad network that included connections with the inferotemporal cortex, dorsolateral prefrontal cortex, and dorsal frontal areas like the supplementary motor area and frontal eye field. Noteworthy, the regression analysis revealed that the more efficient participants in the visual search showed stronger FC between the SPL and areas of primary visual cortex (V1) related to the search task. We shed some light on how the SPL establishes a priority map of the environment during visual attention tasks and how FC is a valuable tool for assessing individual differences while performing cognitive tasks.

  14. Temporary interference over the posterior parietal cortices disrupts thermoregulatory control in humans.

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    Alberto Gallace

    Full Text Available The suggestion has recently been made that certain higher-order cortical areas involved in supporting multisensory representations of the body, and of the space around it, might also play a role in controlling thermoregulatory functions. Here we demonstrate that temporary interference with the function of one of these areas, the posterior parietal cortex, by repetitive transcranial magnetic stimulation, results in a decrease in limb temperature. By contrast, interference with the activity of a sensory-specific area (the primary somatosensory cortex had no effect on temperature. The results of this experiment suggest that associative multisensory brain areas might exert a top-down modulation over basic physiological control. Such a function might be part of a larger neural circuit responsible for maintaining the integrity of the body at both a homeostatic and a psychological level.

  15. Changes in Effective Connectivity of the Superior Parietal Lobe during Inhibition and Redirection of Eye Movements

    Science.gov (United States)

    Asscheman, Susanne J.; Thakkar, Katharine N.; Neggers, Sebastiaan F.W.

    2015-01-01

    Executive control is the ability to flexibly control behavior and is frequently studied with saccadic eye movements. Contrary to frontal oculomotor areas, the role of the superior parietal lobe (SPL) in the executive control of saccades remains unknown. To explore the role of SPL networks in saccade control, we performed a saccadic search-step task while acquiring functional magnetic resonance imaging data for 41 participants. Psychophysiological interaction analyses assessed task-related differences in the effective connectivity of SPL with other brain regions during the inhibition and redirection of saccades. Results indicate an increased coupling of SPL with frontal, posterior, and striatal oculomotor areas for redirected saccades versus visually guided saccades. Saccade inhibition versus unsuccessful inhibition revealed an increased coupling of SPL with dorsolateral prefrontal cortex and anterior cingulate cortex. We discuss how these findings relate to ongoing debates about the implementation of executive control and conclude that early attentional control and rapid updating of saccade goals are important signals for executive control. PMID:27147827

  16. Changes in Effective Connectivity of the Superior Parietal Lobe during Inhibition and Redirection of Eye Movements

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    Susanne J. Asscheman

    2015-01-01

    Full Text Available Executive control is the ability to flexibly control behavior and is frequently studied with saccadic eye movements. Contrary to frontal oculomotor areas, the role of the superior parietal lobe (SPL in the executive control of saccades remains unknown. To explore the role of SPL networks in saccade control, we performed a saccadic search-step task while acquiring functional magnetic resonance imaging data for 41 participants. Psychophysiological interaction analyses assessed task-related differences in the effective connectivity of SPL with other brain regions during the inhibition and redirection of saccades. Results indicate an increased coupling of SPL with frontal, posterior, and striatal oculomotor areas for redirected saccades versus visually guided saccades. Saccade inhibition versus unsuccessful inhibition revealed an increased coupling of SPL with dorsolateral prefrontal cortex and anterior cingulate cortex. We discuss how these findings relate to ongoing debates about the implementation of executive control and conclude that early attentional control and rapid updating of saccade goals are important signals for executive control.

  17. Changes in Effective Connectivity of the Superior Parietal Lobe during Inhibition and Redirection of Eye Movements.

    Science.gov (United States)

    Asscheman, Susanne J; Thakkar, Katharine N; Neggers, Sebastiaan F W

    2015-01-01

    Executive control is the ability to flexibly control behavior and is frequently studied with saccadic eye movements. Contrary to frontal oculomotor areas, the role of the superior parietal lobe (SPL) in the executive control of saccades remains unknown. To explore the role of SPL networks in saccade control, we performed a saccadic search-step task while acquiring functional magnetic resonance imaging data for 41 participants. Psychophysiological interaction analyses assessed task-related differences in the effective connectivity of SPL with other brain regions during the inhibition and redirection of saccades. Results indicate an increased coupling of SPL with frontal, posterior, and striatal oculomotor areas for redirected saccades versus visually guided saccades. Saccade inhibition versus unsuccessful inhibition revealed an increased coupling of SPL with dorsolateral prefrontal cortex and anterior cingulate cortex. We discuss how these findings relate to ongoing debates about the implementation of executive control and conclude that early attentional control and rapid updating of saccade goals are important signals for executive control.

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

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    James Clinton Dooley

    2015-01-01

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

  19. Cortical Hemiballism: A Case of Hemiballismus Associated with Parietal Lobe Infarct.

    Science.gov (United States)

    Shrestha, Pragya; Adhikari, Janak; Poudel, Dilli; Pathak, Ranjan; Karmacharya, Paras

    2015-12-01

    Hemiballismus is characterized by involuntary, irregular, large amplitude, and violent flinging movements of limbs. Stroke (middle and posterior cerebral artery) remains the most common etiology with 2/3 being lacunar. Lesions outside the substantia niagra (STN) can cause hemiballism, and only a minority by STN lesions, unlike the classical belief. Compared to those arising from STN, cortical hemiballismus is usually less severe with a good prognosis. A 61-year-old man presented with sudden onset involuntary flinging movements of his right upper extremity accompanied by numbness and tingling. Past medical history was significant for stroke 2 years back with no residual deficits. Vitals signs were blood pressure of 165/84 mm Hg, and heart rate - 82 beats/min. Irregular, arrhythmic, jerky flinging movement, and decreased sensation to light touch in right upper extremity was noted. Magnetic resonance imaging of the brain revealed acute posterior left parietal lobe infarction. He was treated with aspirin and atorvastatin. Thrombolytic therapy was offered but declined. The movements resolved spontaneously over the next 2 days. No further episodes occurred at 3-month follow-up. Lesions affecting various areas outside the STN can cause hemiballism and usually carries a good prognosis with spontaneous resolution. Acute thrombolytic therapy may be considered on an individual basis. Treatment with antipsychotics can be useful for severe and recurring symptoms.

  20. The role of left superior parietal lobe in male sexual behavior: dynamics of distinct components revealed by FMRI.

    Science.gov (United States)

    Cera, Nicoletta; Di Pierro, Ezio D; Sepede, Gianna; Gambi, Francesco; Perrucci, Mauro Gianni; Merla, Arcangelo; Tartaro, Armando; Del Gratta, Cosimo; Galatioto Paradiso, Giuseppe; Vicentini, Carlo; Romani, Gian Luca; Ferretti, Antonio

    2012-06-01

    Despite the interest for the brain correlates of male sexual arousal, few studies investigated neural mechanisms underlying psychogenic erectile dysfunction (ED). Although these studies showed several brain regions active in ED patients during visual erotic stimulation, the dynamics of inhibition of sexual response is still unclear. This study investigated the dynamics of brain regions involved in the psychogenic ED. Functional magnetic resonance imaging (fMRI) and simultaneous penile tumescence (PT) were used to study brain activity evoked in 17 outpatients with psychogenic ED and 19 healthy controls during visual erotic stimulation. Patterns of brain activation related to different phases of sexual response in the two groups were compared. Simultaneous recording of blood oxygen level-dependent fMRI responses and PT during visual erotic stimulation. During visual erotic stimuli, a larger activation was observed for the patient group in the left superior parietal lobe, ventromedial prefrontal cortex, and posterior cingulate cortex, whereas the control group showed larger activation in the right middle insula and dorsal anterior cingulate cortex and hippocampus. Moreover, the left superior parietal lobe showed a larger activation in patients than controls especially during the later stage of sexual response. Our results suggest that, among regions more active in patient group, the left superior parietal lobe plays a crucial role in inhibition of sexual response. Previous studies showed that left superior parietal lobe is involved in monitoring of internal body representation. The larger activation of this region in patients during later stages of sexual response suggests a high monitoring of the internal body representation, possibly affecting the behavioral response. These findings provide insight on brain mechanisms involved in psychogenic ED. © 2012 International Society for Sexual Medicine.

  1. [Brodmann Areas 39 and 40: Human Parietal Association Area and Higher Cortical Function].

    Science.gov (United States)

    Sakurai, Yasuhisa

    2017-04-01

    The anatomy and function of the angular gyrus (Brodmann Area 39) and supramarginal gyrus (Brodmann Area 40) are described here. Both gyri constitute the inferior part of the parietal lobe. Association fibers from the angular gyrus project to the dorsolateral prefrontal cortex via the superior longitudinal fasciculus (SLF) II/arcuate fasciculus (AF), whereas those from the supramarginal gyrus project to the ventrolateral prefrontal cortex via SLF III/AF. Damage to the left angular gyrus causes kanji agraphia (lexical agraphia) and mild anomia, whereas damage to the left supramarginal gyrus causes kana alexia (phonological dyslexia) and kana agraphia (phonological agraphia). Damage to either gyrus causes Gerstmann's syndrome (finger agnosia, left-right disorientation, agraphia and acalculia) and verbal short-term memory impairment. "Angular alexia with agraphia" results from damage to the middle occipital gyrus posterior to the angular gyrus. Alexia and agraphia, with lesions in the angular or supramarginal gyrus, are characterized by kana transposition errors in reading words, which suggests the impairment of sequential phonological processing.

  2. Increased Intrinsic Activity of Medial-Temporal Lobe Subregions is Associated with Decreased Cortical Thickness of Medial-Parietal Areas in Patients with Alzheimer's Disease Dementia.

    Science.gov (United States)

    Pasquini, Lorenzo; Scherr, Martin; Tahmasian, Masoud; Myers, Nicholas E; Ortner, Marion; Kurz, Alexander; Förstl, Hans; Zimmer, Claus; Grimmer, Timo; Akhrif, Atae; Wohlschläger, Afra M; Riedl, Valentin; Sorg, Christian

    2016-01-01

    In Alzheimer's disease (AD), disrupted connectivity between medial-parietal cortices and medial-temporal lobes (MTL) is linked with increased MTL local functional connectivity, and parietal atrophy is associated with increased MTL memory activation. We hypothesized that intrinsic activity in MTL subregions is increased and associated with medial-parietal degeneration and impaired memory in AD. To test this hypothesis, resting-state-functional and structural-MRI was assessed in 22 healthy controls, 22 mild cognitive impairment patients, and 21 AD-dementia patients. Intrinsic activity was measured by power-spectrum density of blood-oxygenation-level-dependent signal, medial-parietal degeneration by cortical thinning. In AD-dementia patients, intrinsic activity was increased for several right MTL subregions. Raised intrinsic activity in dentate gyrus and cornu ammonis 1 was associated with cortical thinning in posterior cingulate cortices, and at-trend with impaired delayed recall. Critically, increased intrinsic activity in the right entorhinal cortex was associated with ipsilateral posterior cingulate degeneration. Our results provide evidence that in AD, intrinsic activity in MTL subregions is increased and associated with medial-parietal atrophy. Results fit a model in which medial-parietal degeneration contributes to MTL dysconnectivity from medial-parietal cortices, potentially underpinning disinhibition-like changes in MTL activity.

  3. Cortical Connectivity Maps Reveal Anatomically Distinct Areas in the Parietal Cortex of the Rat

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    Aaron eWilber

    2015-01-01

    Full Text Available A central feature of theories of spatial navigation involves the representation of spatial relationships between objects in complex environments. The parietal cortex has long been linked to the processing of spatial visual information and recent evidence from single unit recording in rodents suggests a role for this region in encoding egocentric and world-centered frames. The rat parietal cortex can be subdivided into up to four distinct rostral-caudal and medial-lateral regions, which includes a zone previously characterized as secondary visual cortex. At present, very little is known regarding the relative connectivity of these parietal subdivisions. Thus, we set out to map the connectivity of the entire anterior-posterior and medial-lateral span of this region. To do this we used anterograde and retrograde tracers in conjunction with open source neuronal segmentation and tracer detection tools to generate whole brain connectivity maps of parietal inputs and outputs. Our present results show that inputs to the parietal cortex varied significantly along the medial-lateral, but not the rostral-caudal axis. Specifically, retrosplenial connectivity is greater medially, but connectivity with visual cortex, though generally sparse, is more significant laterally. Finally, based on connection density, the connectivity between parietal cortex and hippocampus is indirect and likely achieved largely via dysgranular retrosplenial cortex. Thus, similar to primates, the parietal cortex of rats exhibits a difference in connectivity along the medial-lateral axis, which may represent functionally distinct areas.

  4. The role of prefrontal and parietal cortices in esthetic appreciation of representational and abstract art: a TMS study.

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    Cattaneo, Zaira; Lega, Carlotta; Gardelli, Chiara; Merabet, Lotfi B; Cela-Conde, Camilo J; Nadal, Marcos

    2014-10-01

    To explain the biological foundations of art appreciation is to explain one of our species' distinctive traits. Previous neuroimaging and electrophysiological studies have pointed to the prefrontal and the parietal cortex as two critical regions mediating esthetic appreciation of visual art. In this study, we applied transcranial magnetic stimulation (TMS) over the left prefrontal cortex and the right posterior parietal cortex while participants were evaluating whether they liked, and by how much, a particular painting. By depolarizing cell membranes in the targeted regions, TMS transiently interferes with the activity of specific cortical areas, which allows clarifying their role in a given task. Our results show that both regions play a fundamental role in mediating esthetic appreciation. Critically though, the effects of TMS varied depending on the type of art considered (i.e. representational vs. abstract) and on participants' a-priori inclination toward one or the other.

  5. Multimodal responses induced by cortical stimulation of the parietal lobe: a stereo-electroencephalography study.

    Science.gov (United States)

    Balestrini, Simona; Francione, Stefano; Mai, Roberto; Castana, Laura; Casaceli, Giuseppe; Marino, Daniela; Provinciali, Leandro; Cardinale, Francesco; Tassi, Laura

    2015-09-01

    The functional complexity of the parietal lobe still represents a challenge for neurophysiological and functional neuroimaging studies. While the somatosensory functions of the anterior parietal cortex are well established, the posterior parietal cortex has a relevant role in processing the sensory information, including visuo-spatial perception, visual attention, visuo-motor transformations and other complex and not completely understood functions. We retrospectively analysed all the clinical manifestations induced by intracerebral bipolar electrical stimulation in 172 patients suffering from drug-resistant focal epilepsy (mean age 25.6, standard deviation 11.6; 44% females and 56% males) with at least one electrode stereotactically implanted in the parietal cortex. A total of 1186 electrical stimulations were included in the analysis, of which 88 were subsequently excluded because of eliciting pathological electric activity or inducing ictal symptomatology. In the dominant parietal lobe, clinical responses were observed for 56 (25%) of the low-frequency stimulations and for 76 (50%) of the high-frequency stimulations. In the non-dominant parietal lobe, 111 (27%) low-frequency and 176 (55%) high-frequency stimulations were associated with a clinical response. Body scheme alteration was the only clinical effect showing a lateralization, as they were evoked only in the non-dominant hemisphere. The occurrence of somatosensory sensations, motor symptoms, dysarthria and multimodal responses were significantly associated with stimulation of the postcentral gyrus (odds ratio: 5.83, P parietal cortex with the aim to evaluate the neurophysiology of this relevant brain region. Our analysis offers a general overview of the multiple roles of the parietal cortex and supports its crucial involvement in different networks related to complex integrative functions.media-1vid110.1093/brain/awv187_video_abstractawv187_video_abstract. © The Author (2015). Published by Oxford

  6. Time course of the involvement of the right anterior superior temporal gyrus and the right fronto-parietal operculum in emotional prosody perception.

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    Marjolijn Hoekert

    Full Text Available In verbal communication, not only the meaning of the words convey information, but also the tone of voice (prosody conveys crucial information about the emotional state and intentions of others. In various studies right frontal and right temporal regions have been found to play a role in emotional prosody perception. Here, we used triple-pulse repetitive transcranial magnetic stimulation (rTMS to shed light on the precise time course of involvement of the right anterior superior temporal gyrus and the right fronto-parietal operculum. We hypothesized that information would be processed in the right anterior superior temporal gyrus before being processed in the right fronto-parietal operculum. Right-handed healthy subjects performed an emotional prosody task. During listening to each sentence a triplet of TMS pulses was applied to one of the regions at one of six time points (400-1900 ms. Results showed a significant main effect of Time for right anterior superior temporal gyrus and right fronto-parietal operculum. The largest interference was observed half-way through the sentence. This effect was stronger for withdrawal emotions than for the approach emotion. A further experiment with the inclusion of an active control condition, TMS over the EEG site POz (midline parietal-occipital junction, revealed stronger effects at the fronto-parietal operculum and anterior superior temporal gyrus relative to the active control condition. No evidence was found for sequential processing of emotional prosodic information from right anterior superior temporal gyrus to the right fronto-parietal operculum, but the results revealed more parallel processing. Our results suggest that both right fronto-parietal operculum and right anterior superior temporal gyrus are critical for emotional prosody perception at a relatively late time period after sentence onset. This may reflect that emotional cues can still be ambiguous at the beginning of sentences, but become

  7. Sleep paralysis and "the bedroom intruder": the role of the right superior parietal, phantom pain and body image projection.

    Science.gov (United States)

    Jalal, Baland; Ramachandran, Vilayanur S

    2014-12-01

    Sleep paralysis (SP) is a common condition occurring either at sleep onset or sleep offset. During SP the sleeper experiences gross motor paralysis while the sensory system is clear. Hypnogogic and hypnopompic hallucinations are common during SP and may involve seeing, hearing, and sensing the presence of menacing intruders in one's bedroom. This "intruder" is often perceived as a shadowy humanoid figure. Supernatural accounts of this hallucinated intruder are common across cultures. In this paper, we postulate that a functional disturbance of the right parietal cortex explains the shadowy nocturnal bedroom intruder hallucination during SP. This hallucination may arise due to a disturbance in the multisensory processing of body and self at the temporoparietal junction. We specifically propose that this perceived intruder is the result of a hallucinated projection of the genetically "hard-wired" body image (homunculus), in the right parietal region; namely, the same circuits that dictate aesthetic and sexual preference of body morphology. One way to test this hypothesis would be to study clinical populations who may have genetically acquired "irregularities" in their internal hard-wired body image in the right superior parietal lobule (SPL); for example, individuals with apotemnophilia or anorexia nervosa. If such individuals experience SP (e.g., induced in a sleep lab), and they hallucinate this shadowy figure, one would predict that they would see humanoid shadows and shapes with body irregularities, mirroring their own internal body image morphology. If correct, our hypothesis will offer a neurological explanation for this nocturnal bedroom intruder that has been a source of controversy, and striking and implausible cultural interpretations throughout history. Indeed, if our proposed hypothesis is tested and corroborated, dissemination of such findings would provide great relief to SP experiencers worldwide and could potentially be used in a therapeutic context.

  8. Posterior Cortical Atrophy Presenting with Superior Arcuate Field Defect

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    Sue Ling Wan

    2015-01-01

    Full Text Available An 80-year-old female with reading difficulty presented with progressive arcuate field defect despite low intraocular pressure. Over a 5-year period, the field defect evolved into an incongruous homonymous hemianopia and the repeated neuroimaging revealed progressive posterior cortical atrophy. Further neuropsychiatric assessment demonstrated symptoms and signs consistent with Benson’s syndrome.

  9. A brain-computer interface based on self-regulation of gamma-oscillations in the superior parietal cortex

    Science.gov (United States)

    Grosse-Wentrup, Moritz; Schölkopf, Bernhard

    2014-10-01

    Objective. Brain-computer interface (BCI) systems are often based on motor- and/or sensory processes that are known to be impaired in late stages of amyotrophic lateral sclerosis (ALS). We propose a novel BCI designed for patients in late stages of ALS that only requires high-level cognitive processes to transmit information from the user to the BCI. Approach. We trained subjects via EEG-based neurofeedback to self-regulate the amplitude of gamma-oscillations in the superior parietal cortex (SPC). We argue that parietal gamma-oscillations are likely to be associated with high-level attentional processes, thereby providing a communication channel that does not rely on the integrity of sensory- and/or motor-pathways impaired in late stages of ALS. Main results. Healthy subjects quickly learned to self-regulate gamma-power in the SPC by alternating between states of focused attention and relaxed wakefulness, resulting in an average decoding accuracy of 70.2%. One locked-in ALS patient (ALS-FRS-R score of zero) achieved an average decoding accuracy significantly above chance-level though insufficient for communication (55.8%). Significance. Self-regulation of gamma-power in the SPC is a feasible paradigm for brain-computer interfacing and may be preserved in late stages of ALS. This provides a novel approach to testing whether completely locked-in ALS patients retain the capacity for goal-directed thinking.

  10. Reaching in depth: hand position dominates over binocular eye position in the rostral superior parietal lobule.

    Science.gov (United States)

    Ferraina, Stefano; Brunamonti, Emiliano; Giusti, Maria Assunta; Costa, Stefania; Genovesio, Aldo; Caminiti, Roberto

    2009-09-16

    Neural activity was recorded in area PE (dorsorostral part of Brodmann's area 5) of the posterior parietal cortex while monkeys performed arm reaching toward memorized targets located at different distances from the body. For any given distance, arm movements were performed while the animal kept binocular eye fixation constant. Under these conditions, the activity of a large proportion (36%) of neurons was modulated by reach distance during the memory period. By varying binocular eye position (vergence angle) and initial hand position, we found that the reaching-related activity of most neurons (61%) was influenced by changing the starting position of the hand, whereas that of a smaller, although substantial, population (13%) was influenced by changes of binocular eye position (i.e., by the angle of vergence). Furthermore, the modulation of the neural activity was better explained expressing the reach movement end-point, corresponding to the memorized target location, in terms of distance from the initial hand position, rather than from the body. These results suggest that the activity of neurons in area PE combines information about eye and hand position to encode target distance for reaching in depth predominantly in hand coordinates. This encoding mechanism is consistent with the position of PE in the functional gradient that characterizes the parieto-frontal network underlying reaching.

  11. Decoding a wide range of hand configurations from macaque motor, premotor, and parietal cortices.

    Science.gov (United States)

    Schaffelhofer, Stefan; Agudelo-Toro, Andres; Scherberger, Hansjörg

    2015-01-21

    Despite recent advances in decoding cortical activity for motor control, the development of hand prosthetics remains a major challenge. To reduce the complexity of such applications, higher cortical areas that also represent motor plans rather than just the individual movements might be advantageous. We investigated the decoding of many grip types using spiking activity from the anterior intraparietal (AIP), ventral premotor (F5), and primary motor (M1) cortices. Two rhesus monkeys were trained to grasp 50 objects in a delayed task while hand kinematics and spiking activity from six implanted electrode arrays (total of 192 electrodes) were recorded. Offline, we determined 20 grip types from the kinematic data and decoded these hand configurations and the grasped objects with a simple Bayesian classifier. When decoding from AIP, F5, and M1 combined, the mean accuracy was 50% (using planning activity) and 62% (during motor execution) for predicting the 50 objects (chance level, 2%) and substantially larger when predicting the 20 grip types (planning, 74%; execution, 86%; chance level, 5%). When decoding from individual arrays, objects and grip types could be predicted well during movement planning from AIP (medial array) and F5 (lateral array), whereas M1 predictions were poor. In contrast, predictions during movement execution were best from M1, whereas F5 performed only slightly worse. These results demonstrate for the first time that a large number of grip types can be decoded from higher cortical areas during movement preparation and execution, which could be relevant for future neuroprosthetic devices that decode motor plans.

  12. Motor learning in individuals with autism spectrum disorder: activation in superior parietal lobule related to learning and repetitive behaviors.

    Science.gov (United States)

    Travers, Brittany G; Kana, Rajesh K; Klinger, Laura G; Klein, Christopher L; Klinger, Mark R

    2015-02-01

    Motor-linked implicit learning is the learning of a sequence of movements without conscious awareness. Although motor symptoms are frequently reported in individuals with autism spectrum disorder (ASD), recent behavioral studies have suggested that motor-linked implicit learning may be intact in ASD. The serial reaction time (SRT) task is one of the most common measures of motor-linked implicit learning. The present study used a 3T functional magnetic resonance imaging scanner to examine the behavioral and neural correlates of real-time motor sequence learning in adolescents and adults with ASD (n = 15) compared with age- and intelligence quotient-matched individuals with typical development (n = 15) during an SRT task. Behavioral results suggested less robust motor sequence learning in individuals with ASD. Group differences in brain activation suggested that individuals with ASD, relative to individuals with typical development, showed decreased activation in the right superior parietal lobule (SPL) and right precuneus (Brodmann areas 5 and 7, and extending into the intraparietal sulcus) during learning. Activation in these areas (and in areas such as the right putamen and right supramarginal gyrus) was found to be significantly related to behavioral learning in this task. Additionally, individuals with ASD who had more severe repetitive behavior/restricted interest symptoms demonstrated greater decreased activation in these regions during motor learning. In conjunction, these results suggest that the SPL may play an important role in motor learning and repetitive behavior in individuals with ASD.

  13. Evaluating the roles of the inferior frontal gyrus and superior parietal lobule in deductive reasoning: an rTMS study.

    Science.gov (United States)

    Tsujii, Takeo; Sakatani, Kaoru; Masuda, Sayako; Akiyama, Takekazu; Watanabe, Shigeru

    2011-09-15

    This study used off-line repetitive transcranial magnetic stimulation (rTMS) to examine the roles of the superior parietal lobule (SPL) and inferior frontal gyrus (IFG) in a deductive reasoning task. Subjects performed a categorical syllogistic reasoning task involving congruent, incongruent, and abstract trials. Twenty four subjects received magnetic stimulation to the SPL region prior to the task. In the other 24 subjects, TMS was administered to the IFG region before the task. Stimulation lasted for 10min, with an inter-pulse frequency of 1Hz. We found that bilateral SPL (Brodmann area (BA) 7) stimulation disrupted performance on abstract and incongruent reasoning. Left IFG (BA 45) stimulation impaired congruent reasoning performance while paradoxically facilitating incongruent reasoning performance. This resulted in the elimination of the belief-bias. In contrast, right IFG stimulation only impaired incongruent reasoning performance, thus enhancing the belief-bias effect. These findings are largely consistent with the dual-process theory of reasoning, which proposes the existence of two different human reasoning systems: a belief-based heuristic system; and a logic-based analytic system. The present findings suggest that the left language-related IFG (BA 45) may correspond to the heuristic system, while bilateral SPL may underlie the analytic system. The right IFG may play a role in blocking the belief-based heuristic system for solving incongruent reasoning trials. This study could offer an insight about functional roles of distributed brain systems in human deductive reasoning by utilizing the rTMS approach.

  14. 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

  15. Sensory syndromes in parietal stroke.

    Science.gov (United States)

    Bassetti, C; Bogousslavsky, J; Regli, F

    1993-10-01

    We studied 20 patients with an acute parietal stroke with hemisensory disturbances but no visual field deficit and no or only slight motor weakness, without thalamic involvement on CT or MRI and found three main sensory syndromes. (1) The pseudothalamic sensory syndrome consists of a faciobrachiocrural impairment of elementary sensation (touch, pain, temperature, vibration). All patients have an inferior-anterior parietal stroke involving the parietal operculum, posterior insula, and, in all but one patient, underlying white matter. (2) The cortical sensory syndrome consists of an isolated loss of discriminative sensation (stereognosis, graphesthesia, position sense) involving one or two parts of the body. These patients show a superior-posterior parietal stroke. (3) The atypical sensory syndrome consists of a sensory loss involving all modalities of sensation in a partial distribution. Parietal lesions of different topography are responsible for this clinical picture, which probably represents a minor variant of the two previous sensory syndromes. Neuropsychological dysfunction was present in 17 patients. The only constant association was between conduction aphasia and right-sided pseudothalamic sensory deficit. We conclude that parietal stroke can cause different sensory syndromes depending on the topography of the underlying lesion. Sensory deficits can be monosymptomatic but never present as a "pure sensory stroke" involving face, arm, leg, and trunk together.

  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

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    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. Differential roles of the frontal and parietal cortices in the control of saccades.

    Science.gov (United States)

    Bender, Julia; Tark, Kyeong-Jin; Reuter, Benedikt; Kathmann, Norbert; Curtis, Clayton E

    2013-10-01

    Although externally as well as internally-guided eye movements allow us to flexibly explore the visual environment, their differential neural mechanisms remain elusive. A better understanding of these neural mechanisms will help us to understand the control of action and to elucidate the nature of cognitive deficits in certain psychiatric populations (e.g., schizophrenia) that show increased latencies in volitional but not visually-guided saccades. Both the superior precentral sulcus (sPCS) and the intraparietal sulcus (IPS) are implicated in the control of eye movements. However, it remains unknown what differential contributions the two areas make to the programming of visually-guided and internally-guided saccades. In this study we tested the hypotheses that sPCS and IPS distinctly encode internally-guided saccades and visually-guided saccades. We scanned subjects with fMRI while they generated visually-guided and internally-guided delayed saccades. We used multi-voxel pattern analysis to test whether patterns of cue related, preparatory and saccade related activation could be used to predict the direction of the planned eye movement. Results indicate that patterns in the human sPCS predicted internally-guided saccades but not visually-guided saccades in all trial periods and patterns in the IPS predicted internally-guided saccades and visually-guided saccades equally well. The results support the hypothesis that the human sPCS and IPS make distinct contributions to the control of volitional eye movements.

  18. Effects of glossy privet fruit on neural cell apoptosis in the cortical parietal lobe and hippocampal CA1 region of vascular dementia rats

    Institute of Scientific and Technical Information of China (English)

    Jing Cai; Fan Zhou; Jian Du

    2008-01-01

    BACKGROUND: Glossy privet fruit inhibits neural cell apoptosis following the onset of vascular dementia. OBJECTIVE: To confirm glossy privet fruit effects on neural cell apoptosis in the cortical parietal lobe and hippocampal CA1 region of rat models of vascular dementia using molecular biology techniques. DESIGN, TIME AND SETTING: The neural cell morphology experiment was performed at the Laboratory of Flow Cells and Biochemistry, Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, and the Basic Room of Pathology, Academy of Chinese Medicine from December 2006 to May 2008.MATERIALS: A total of 60 Wistar rats were used to establish vascular dementia models using a photochemical reaction method. Glossy privet fruit was purchased from Fujian, China. Hydergine was co-produced by Sandoz, Switzerland and Huajin, China. METHODS: The 60 Wistar rats were randomly divided into 6 equal sized groups (n = 10), I.e. Model, blank, high, moderate and low doses of Chinese medicine, and hydergine control groups. Rats in the model group were treated with distilled water (1 mL/100 g) by gavage following model establishment. Rats in the blank group underwent experimental procedures as for the model group, except that rat models were created without illumination. Rats in the high, moderate and low doses of Chinese medicine groups, and the hydergine control group respectively received high, moderate and low doses of glossy privet fruit, and hydergine suspension (1 mL/100 g) by gavage, once a day, for 30 days. MAIN OUTCOME MEASURES: Morphology of neural cells from the rat cortical parietal lobe and hippocampal CA1 region of all groups was observed with an electron microscope. Positive neural cells in the injury site of the rat cortical parietal lobe and hippocampal CA1 region were investigated using the Fas immunohistochemical method. Absorbance of Fas-positive neurons was detected by the MPIAS-500 multimedia color imaging analysis system. RESULTS: Neural

  19. Cortical porosity not superior to conventional densitometry in identifying hemodialysis patients with fragility fracture

    Science.gov (United States)

    Patsch, Janina M.; Fischer, Lukas; Bojic, Marija; Winnicki, Wolfgang; Weber, Michael; Cejka, Daniel

    2017-01-01

    Hemodialysis (HD) patients face increased fracture risk, which is further associated with elevated risk of hospitalization and mortality. High-resolution peripheral computed tomography (HR-pQCT) has advanced our understanding of bone disease in chronic kidney disease by characterizing distinct changes in both the cortical and trabecular compartments. Increased cortical porosity (Ct.Po) has been shown to be associated with fracture in patients with osteopenia or in postmenopausal diabetic women. We tested whether the degree of Ct.Po identifies hemodialysis patients with prevalent fragility fractures in comparison to bone mineral density (BMD) assessed by dual X-ray absorptiometry (DXA). We performed a post-hoc analysis of a cross-sectional study in 76 prevalent hemodialysis patients. Markers of mineral metabolism, coronary calcification score, DXA-, and HR-pQCT-data were analyzed, and Ct.Po determined at radius and tibia. Ct.Po was significantly higher in patients with fracture but association was lost after adjusting for age and gender (tibia p = 0.228, radius p = 0.5). Instead, femoral (F) BMD neck area (p = 0.03), F T-score neck area (p = 0.03), radius (R) BMD (p = 0.03), R T-score (p = 0.03), and cortical HR-pQCT indices such as cortical area (Ct.Ar) (tibia: p = 0.01; radius: p = 0.02) and cortical thickness (Ct.Th) (tibia: p = 0.03; radius: p = 0.02) correctly classified patients with fragility fractures. Area under receiver operating characteristic curves (AUC) for Ct.Po (tibia AUC: 0.711; p = 0.01; radius AUC: 0.666; p = 0.04), Ct.Ar (tibia AUC: 0.832; p<0.001; radius AUC: 0.796; p<0.001), and F neck BMD (AUC: 0.758; p = 0.002) did not differ significantly among each other. In conclusion, measuring Ct.Po is not superior to BMD determined by DXA for identification of HD patients with fragility fracture. PMID:28199411

  20. Mapping auditory core, lateral belt, and parabelt cortices in the human superior temporal gyrus

    DEFF Research Database (Denmark)

    Sweet, Robert A; Dorph-Petersen, Karl-Anton; Lewis, David A

    2005-01-01

    the location of the lateral belt and parabelt with respect to gross anatomical landmarks. Architectonic criteria for the core, lateral belt, and parabelt were readily adapted from monkey to human. Additionally, we found evidence for an architectonic subdivision within the parabelt, present in both species......The goal of the present study was to determine whether the architectonic criteria used to identify the core, lateral belt, and parabelt auditory cortices in macaque monkeys (Macaca fascicularis) could be used to identify homologous regions in humans (Homo sapiens). Current evidence indicates...... that auditory cortex in humans, as in monkeys, is located on the superior temporal gyrus (STG), and is functionally and structurally altered in illnesses such as schizophrenia and Alzheimer's disease. In this study, we used serial sets of adjacent sections processed for Nissl substance, acetylcholinesterase...

  1. The Left Superior Longitudinal Fasciculus within the Primary Sensory Area of Inferior Parietal Lobe Plays a Role in Dysgraphia of Kana Omission within Sentences

    Directory of Open Access Journals (Sweden)

    Nobusada Shinoura

    2012-01-01

    Full Text Available Functional neurological changes after surgery combined with diffusion tensor imaging (DTI tractography can directly provide evidence of anatomical localization of brain function. Using these techniques, a patient with dysgraphia before surgery was analyzed at our hospital in 2011. The patient showed omission of kana within sentences before surgery, which improved after surgery. The brain tumor was relatively small and was located within the primary sensory area (S1 of the inferior parietal lobe (IPL. DTI tractography before surgery revealed compression of the branch of the superior longitudinal fasciculus (SLF by the brain tumor. These results suggest that the left SLF within the S1 of IPL plays a role in the development of dysgraphia of kana omission within sentences.

  2. Positive symptoms associate with cortical thinning in the superior temporal gyrus via the ENIGMA Schizophrenia consortium.

    Science.gov (United States)

    Walton, E; Hibar, D P; van Erp, T G M; Potkin, S G; Roiz-Santiañez, R; Crespo-Facorro, B; Suarez-Pinilla, P; Van Haren, N E M; de Zwarte, S M C; Kahn, R S; Cahn, W; Doan, N T; Jørgensen, K N; Gurholt, T P; Agartz, I; Andreassen, O A; Westlye, L T; Melle, I; Berg, A O; Mørch-Johnsen, L; Faerden, A; Flyckt, L; Fatouros-Bergman, H; Jönsson, E G; Hashimoto, R; Yamamori, H; Fukunaga, M; Preda, A; De Rossi, P; Piras, F; Banaj, N; Ciullo, V; Spalletta, G; Gur, R E; Gur, R C; Wolf, D H; Satterthwaite, T D; Beard, L M; Sommer, I E; Koops, S; Gruber, O; Richter, A; Krämer, B; Kelly, S; Donohoe, G; McDonald, C; Cannon, D M; Corvin, A; Gill, M; Di Giorgio, A; Bertolino, A; Lawrie, S; Nickson, T; Whalley, H C; Neilson, E; Calhoun, V D; Thompson, P M; Turner, J A; Ehrlich, S

    2017-05-01

    Based on the role of the superior temporal gyrus (STG) in auditory processing, language comprehension and self-monitoring, this study aimed to investigate the relationship between STG cortical thickness and positive symptom severity in schizophrenia. This prospective meta-analysis includes data from 1987 individuals with schizophrenia collected at seventeen centres around the world that contribute to the ENIGMA Schizophrenia Working Group. STG thickness measures were extracted from T1-weighted brain scans using FreeSurfer. The study performed a meta-analysis of effect sizes across sites generated by a model predicting left or right STG thickness with a positive symptom severity score (harmonized SAPS or PANSS-positive scores), while controlling for age, sex and site. Secondary models investigated relationships between antipsychotic medication, duration of illness, overall illness severity, handedness and STG thickness. Positive symptom severity was negatively related to STG thickness in both hemispheres (left: βstd = -0.052; P = 0.021; right: βstd = -0.073; P = 0.001) when statistically controlling for age, sex and site. This effect remained stable in models including duration of illness, antipsychotic medication or handedness. Our findings further underline the important role of the STG in hallmark symptoms in schizophrenia. These findings can assist in advancing insight into symptom-relevant pathophysiological mechanisms in schizophrenia. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Cortico-cortical connectivity between right parietal and bilateral primary motor cortices during imagined and observed actions: A combined TMS/tDCS study.

    Directory of Open Access Journals (Sweden)

    Matteo eFeurra

    2011-08-01

    Full Text Available Previous TMS studies showed functional connections between the parietal cortex (PC and the primary motor cortex (M1 during tasks of different reaching-to-grasp movements. Here, we tested whether the same network is involved in cognitive processes such as imagined or observed actions. Single pulse TMS of the right and left M1 during rest and during a motor imagery and an action observation task (i.e. an index-thumb pinch grip in both cases was used to measure corticospinal excitability changes before and after conditioning of the right PC by 10 minutes of cathodal, anodal or sham transcranial direct current stimulation (tDCS. Corticospinal excitability was indexed by the size of motor evoked potentials (MEPs from the contralateral FDI (target and ADM (control muscles. Results showed selective ipsilateral effects on the M1 excitability, exclusively for motor imagery processes: anodal tDCS enhanced the MEPs’ size from the FDI muscle, whereas cathodal tDCS decreased it. Only cathodal tDCS impacted corticospinal facilitation induced by action observation. Sham stimulation was always uneffective. These results suggest that motor imagery, differently from action observation, is sustained by a strictly ipsilateral parieto-motor cortex circuits. Results might have implication for neuromodulatory rehabilitative purposes.

  4. Occlusion of the pig superior sagittal sinus, bridging and cortical veins: multistep evolution of sinus-vein thrombosis.

    Science.gov (United States)

    Fries, G; Wallenfang, T; Hennen, J; Velthaus, M; Heimann, A; Schild, H; Perneczky, A; Kempski, O

    1992-07-01

    Cerebral sinus-vein thrombosis may lead to severe hemodynamic changes, elevated intracranial pressure (ICP), and brain edema. It is supposed that progression of the thrombus from the sinus into bridging and cortical veins plays a key role in the development of these pathophysiological changes, but this hypothesis lacks experimental proof. The aim of this study, using a novel animal model of sinus-vein thrombosis, was to evaluate the effects of a standardized occlusion of the superior sagittal sinus and its bridging and cortical veins on hemodynamic alterations, on brain water content, and on ICP in domestic pigs. In 10 animals, the middle third of the superior sagittal sinus was occluded with a catheter-guided balloon. Five of these pigs received an additional injection of 1 ml fibrin glue into the superior sagittal sinus anterior to the inflated balloon, leading to an obstruction of bridging and cortical veins. In five control animals the balloon was inserted but not inflated. Five pigs underwent cerebral angiography. Four hours after occlusion, the brains were frozen in liquid nitrogen, and coronal slices were examined for Evans blue dye extravasation, regional water content, and histological changes. Occlusion of the superior sagittal sinus alone did not affect ICP or cerebral perfusion pressure (CPP). The additional injection of fibrin glue caused an obstruction of cortical and bridging veins as well as severe increases in mean (+/- standard deviation) ICP to 49.4 +/- 14.3 mm Hg, compared with 8.3 +/- 4.5 mm Hg in sham-treated controls and 7.1 +/- 3.9 mm Hg in animals with occlusion of the superior sagittal sinus alone. There was also a steep fall in the mean CPP to 34.2 +/- 19.6 mm Hg compared with 96.4 +/- 13.8 mm Hg in the control group. White-matter water content anterior to the occlusion site was elevated to 81.9 +/- 3.7 gm/100 gm frozen weight in the fibrin group as compared to 70.7 +/- 2.2 gm/100 gm in controls. Posterior to the occlusion site, water

  5. Effect of the stimulus frequency and pulse number of repetitive transcranial magnetic stimulation on the inter-reversal time of perceptual reversal on the right superior parietal lobule

    Science.gov (United States)

    Nojima, Kazuhisa; Ge, Sheng; Katayama, Yoshinori; Ueno, Shoogo; Iramina, Keiji

    2010-05-01

    The aim of this study is to investigate the effect of the stimulus frequency and pulses number of repetitive transcranial magnetic stimulation (rTMS) on the inter-reversal time (IRT) of perceptual reversal on the right superior parietal lobule (SPL). The spinning wheel illusion was used as the ambiguous figures stimulation in this study. To investigate the rTMS effect over the right SPL during perceptual reversal, 0.25 Hz 60 pulse, 1 Hz 60 pulse, 0.5 Hz 120 pulse, 1 Hz 120 pulse, and 1 Hz 240 pulse biphasic rTMS at 90% of resting motor threshold was applied over the right SPL and the right posterior temporal lobe (PTL), respectively. As a control, a no TMS was also conducted. It was found that rTMS on 0.25 Hz 60 pulse and 1 Hz 60 pulse applied over the right SPL caused shorter IRT. In contrast, it was found that rTMS on 1 Hz 240-pulse applied over the right SPL caused longer IRT. On the other hand, there is no significant difference between IRTs when the rTMS on 0.5 Hz 120 pulse and 1 Hz 120 pulse were applied over the right SPL. Therefore, the applying of rTMS over the right SPL suggests that the IRT of perceptual reversal is effected by the rTMS conditions such as the stimulus frequency and the number of pulses.

  6. Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence.

    Science.gov (United States)

    Schilling, C; Kühn, S; Paus, T; Romanowski, A; Banaschewski, T; Barbot, A; Barker, G J; Brühl, R; Büchel, C; Conrod, P J; Dalley, J W; Flor, H; Ittermann, B; Ivanov, N; Mann, K; Martinot, J-L; Nees, F; Rietschel, M; Robbins, T W; Smolka, M N; Ströhle, A; Kathmann, N; Garavan, H; Heinz, A; Schumann, G; Gallinat, J

    2013-05-01

    Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits.

  7. Sex, age, and cognitive correlates of asymmetries in thickness of the cortical mantle across the life span

    DEFF Research Database (Denmark)

    Plessen, Kerstin J; Hugdahl, Kenneth; Bansal, Ravi

    2014-01-01

    lateral, dorsal, and mesial surfaces of the frontal lobe, extending into primary sensory, superior parietal, and anterior superior temporal cortices. A right > left asymmetry was present in the lateral, mesial, and dorsal surfaces of the posterior temporal, parietal, and occipital cortices, as well...... as in the entire inferior surface of the brain. An exaggerated left > right asymmetry was detected in females in anterior brain regions, and an exaggerated right > left asymmetry was detected in males in the orbitofrontal, inferior parietal, and inferior occipital cortices. Weaker moderating effects of sex were...... scattered along the mesial surface of the brain. Age significantly moderated asymmetry measures in the inferior sensorimotor, inferior parietal, posterior temporal, and inferior occipital cortices. The age × asymmetry interaction derived from a steeper decline in cortical thickness with age in the right...

  8. Cancellous Screws Are Biomechanically Superior to Cortical Screws in Metaphyseal Bone.

    Science.gov (United States)

    Wang, Tim; Boone, Christopher; Behn, Anthony W; Ledesma, Justin B; Bishop, Julius A

    2016-09-01

    Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. This study compares the biomechanical properties of commercially available cortical and cancellous screw designs in a synthetic model representing various bone densities. Commercially available, fully threaded, 4.0-mm outer-diameter cortical and cancellous screws were tested in terms of pullout strength and maximum insertion torque in standard-density and osteoporotic cancellous bone models. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixation. [Orthopedics.2016; 39(5):e828-e832.].

  9. Correlations between brain cortical thickness and cutaneous pain thresholds are atypical in adults with migraine.

    Directory of Open Access Journals (Sweden)

    Todd J Schwedt

    Full Text Available BACKGROUND/OBJECTIVE: Migraineurs have atypical pain processing, increased expectations for pain, and hypervigilance for pain. Recent studies identified correlations between brain structure and pain sensation in healthy adults. The objective of this study was to compare cortical thickness-to-pain threshold correlations in migraineurs to healthy controls. We hypothesized that migraineurs would have aberrant relationships between the anatomical neurocorrelates of pain processing and pain thresholds. METHODS: Pain thresholds to cutaneously applied heat were determined for 31 adult migraineurs and 32 healthy controls. Cortical thickness was determined from magnetic resonance imaging T1-weighted sequences. Regional cortical thickness-to-pain threshold correlations were determined for migraineurs and controls separately using a general linear model whole brain vertex-wise analysis. A pain threshold-by-group interaction analysis was then conducted to estimate regions where migraineurs show alterations in the pain threshold-to-cortical thickness correlations relative to healthy controls. RESULTS: Controls had negative correlations (p<0.01 uncorrected between pain thresholds and cortical thickness in left posterior cingulate/precuneus, right superior temporal, right inferior parietal, and left inferior temporal regions, and a negative correlation (p<0.01 Monte Carlo corrected with a left superior temporal/inferior parietal region. Migraineurs had positive correlations (p<0.01 uncorrected between pain thresholds and cortical thickness in left superior temporal/inferior parietal, right precuneus, right superior temporal/inferior parietal, and left inferior parietal regions. Cortical thickness-to-pain threshold correlations differed between migraine and control groups (p<0.01 uncorrected for right superior temporal/inferior parietal, right precentral, left posterior cingulate/precuneus, and right inferior parietal regions and (p<0.01 Monte Carlo corrected

  10. Xenomelia: a new right parietal lobe syndrome.

    Science.gov (United States)

    McGeoch, Paul D; Brang, David; Song, Tao; Lee, Roland R; Huang, Mingxiong; Ramachandran, V S

    2011-12-01

    Damage to the right parietal lobe has long been associated with various disorders of body image. The authors have recently suggested that an unusual behavioural condition in which otherwise rational individuals desire the amputation of a healthy limb might also arise from right parietal dysfunction. Four subjects who desired the amputation of healthy legs (two right, one left and one, at first, bilateral and then left only) were recruited and underwent magnetoencephalography (MEG) scans during tactile stimulation of sites above and below the desired amputation line. Regions of interest (ROIs) in each hemisphere (superior parietal lobule (SPL), inferior parietal lobule, S1, M1, insula, premotor cortex and precuneus) were defined using FreeSurfer software. Analysis of average MEG activity across the 40-140 ms post-stimulation timeframe was carried out using an unpaired t test. This revealed significantly reduced activation only in the right SPL ROI for the subjects' affected legs when compared with both subjects' unaffected legs and that of controls. The right SPL is a cortical area that appears ideally placed to unify disparate sensory inputs to create a coherent sense of having a body. The authors propose that inadequate activation of the right SPL leads to the unnatural situation in which the sufferers can feel the limb in question being touched without it actually incorporating into their body image, with a resulting desire for amputation. The authors introduce the term 'xenomelia' as a more appropriate name than apotemnophilia or body integrity identity disorder, for what appears to be an unrecognised right parietal lobe syndrome.

  11. Explaining the high voice superiority effect in polyphonic music: evidence from cortical evoked potentials and peripheral auditory models.

    Science.gov (United States)

    Trainor, Laurel J; Marie, Céline; Bruce, Ian C; Bidelman, Gavin M

    2014-02-01

    Natural auditory environments contain multiple simultaneously-sounding objects and the auditory system must parse the incoming complex sound wave they collectively create into parts that represent each of these individual objects. Music often similarly requires processing of more than one voice or stream at the same time, and behavioral studies demonstrate that human listeners show a systematic perceptual bias in processing the highest voice in multi-voiced music. Here, we review studies utilizing event-related brain potentials (ERPs), which support the notions that (1) separate memory traces are formed for two simultaneous voices (even without conscious awareness) in auditory cortex and (2) adults show more robust encoding (i.e., larger ERP responses) to deviant pitches in the higher than in the lower voice, indicating better encoding of the former. Furthermore, infants also show this high-voice superiority effect, suggesting that the perceptual dominance observed across studies might result from neurophysiological characteristics of the peripheral auditory system. Although musically untrained adults show smaller responses in general than musically trained adults, both groups similarly show a more robust cortical representation of the higher than of the lower voice. Finally, years of experience playing a bass-range instrument reduces but does not reverse the high voice superiority effect, indicating that although it can be modified, it is not highly neuroplastic. Results of new modeling experiments examined the possibility that characteristics of middle-ear filtering and cochlear dynamics (e.g., suppression) reflected in auditory nerve firing patterns might account for the higher-voice superiority effect. Simulations show that both place and temporal AN coding schemes well-predict a high-voice superiority across a wide range of interval spacings and registers. Collectively, we infer an innate, peripheral origin for the higher-voice superiority observed in human

  12. Increased Cortical Thickness in Professional On-Line Gamers

    Science.gov (United States)

    Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam

    2013-01-01

    Objective The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. Methods High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. Results Career length was positively correlated with cortical thickness in three brain regions: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Conclusion Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility. PMID:24474988

  13. Increased cortical thickness in professional on-line gamers.

    Science.gov (United States)

    Hyun, Gi Jung; Shin, Yong Wook; Kim, Bung-Nyun; Cheong, Jae Hoon; Jin, Seong Nam; Han, Doug Hyun

    2013-12-01

    The bulk of recent studies have tested whether video games change the brain in terms of activity and cortical volume. However, such studies are limited by several factors including cross-sectional comparisons, co-morbidity, and short-term follow-up periods. In the present study, we hypothesized that cognitive flexibility and the volume of brain cortex would be correlated with the career length of on-line pro-gamers. High-resolution magnetic resonance scans were acquired in twenty-three pro-gamers recruited from StarCraft pro-game teams. We measured cortical thickness in each individual using FreeSurfer and the cortical thickness was correlated with the career length and the performance of the pro-gamers. CAREER LENGTH WAS POSITIVELY CORRELATED WITH CORTICAL THICKNESS IN THREE BRAIN REGIONS: right superior frontal gyrus, right superior parietal gyrus, and right precentral gyrus. Additionally, increased cortical thickness in the prefrontal cortex was correlated with winning rates of the pro-game league. Increased cortical thickness in the prefrontal and parietal cortices was also associated with higher performance of Wisconsin Card Sorting Test. Our results suggest that in individuals without pathologic conditions, regular, long-term playing of on-line games is associated with volume changes in the prefrontal and parietal cortices, which are associated with cognitive flexibility.

  14. Effects of parietal TMS on visual and auditory processing at the primary cortical level -- a concurrent TMS-fMRI study

    DEFF Research Database (Denmark)

    Leitão, Joana; Thielscher, Axel; Werner, Sebastian

    2013-01-01

    Accumulating evidence suggests that multisensory interactions emerge already at the primary cortical level. Specifically, auditory inputs were shown to suppress activations in visual cortices when presented alone but amplify the blood oxygen level-dependent (BOLD) responses to concurrent visual i...

  15. Brain activity dynamics in human parietal regions during spontaneous switches in bistable perception.

    Science.gov (United States)

    Megumi, Fukuda; Bahrami, Bahador; Kanai, Ryota; Rees, Geraint

    2015-02-15

    The neural mechanisms underlying conscious visual perception have been extensively investigated using bistable perception paradigms. Previous functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) studies suggest that the right anterior superior parietal (r-aSPL) and the right posterior superior parietal lobule (r-pSPL) have opposite roles in triggering perceptual reversals. It has been proposed that these two areas are part of a hierarchical network whose dynamics determine perceptual switches. However, how these two parietal regions interact with each other and with the rest of the brain during bistable perception is not known. Here, we investigated such a model by recording brain activity using fMRI while participants viewed a bistable structure-from-motion stimulus. Using dynamic causal modeling (DCM), we found that resolving such perceptual ambiguity was specifically associated with reciprocal interactions between these parietal regions and V5/MT. Strikingly, the strength of bottom-up coupling between V5/MT to r-pSPL and from r-pSPL to r-aSPL predicted individual mean dominance duration. Our findings are consistent with a hierarchical predictive coding model of parietal involvement in bistable perception and suggest that visual information processing underlying spontaneous perceptual switches can be described as changes in connectivity strength between parietal and visual cortical regions.

  16. Effects of parietal TMS on visual and auditory processing at the primary cortical level -- a concurrent TMS-fMRI study.

    Science.gov (United States)

    Leitão, Joana; Thielscher, Axel; Werner, Sebastian; Pohmann, Rolf; Noppeney, Uta

    2013-04-01

    Accumulating evidence suggests that multisensory interactions emerge already at the primary cortical level. Specifically, auditory inputs were shown to suppress activations in visual cortices when presented alone but amplify the blood oxygen level-dependent (BOLD) responses to concurrent visual inputs (and vice versa). This concurrent transcranial magnetic stimulation-functional magnetic resonance imaging (TMS-fMRI) study applied repetitive TMS trains at no, low, and high intensity over right intraparietal sulcus (IPS) and vertex to investigate top-down influences on visual and auditory cortices under 3 sensory contexts: visual, auditory, and no stimulation. IPS-TMS increased activations in auditory cortices irrespective of sensory context as a result of direct and nonspecific auditory TMS side effects. In contrast, IPS-TMS modulated activations in the visual cortex in a state-dependent fashion: it deactivated the visual cortex under no and auditory stimulation but amplified the BOLD response to visual stimulation. However, only the response amplification to visual stimulation was selective for IPS-TMS, while the deactivations observed for IPS- and Vertex-TMS resulted from crossmodal deactivations induced by auditory activity to TMS sounds. TMS to IPS may increase the responses in visual (or auditory) cortices to visual (or auditory) stimulation via a gain control mechanism or crossmodal interactions. Collectively, our results demonstrate that understanding TMS effects on (uni)sensory processing requires a multisensory perspective.

  17. Short-Term Internet-Search Training Is Associated with Increased Fractional Anisotropy in the Superior Longitudinal Fasciculus in the Parietal Lobe.

    Science.gov (United States)

    Dong, Guangheng; Li, Hui; Potenza, Marc N

    2017-01-01

    The Internet search engine has become an indispensable tool for many people, yet the ways in which Internet searching may alter brain structure and function is poorly understood. In this study, we investigated the influence of short-term Internet-search "training" on white matter microstructure using diffusion tensor imaging (DTI). Fifty-nine valid subjects (Experimental group, 43; Control group, 16) completed the whole procedure: pre- DTI scan, 6-day's training and post- DTI scan. Using track-based spatial statistics, we found increased fractional anisotropy in the right superior longitudinal fasciculus at post-test as compared to pre-test in experimental group. Within the identified region of the right superior longitudinal fasciculus, decreased radial diffusivity (RD), and unchanged axial diffusivity (AD) were observed. These results suggest that short-term Internet-search training may increase white-matter integrity in the right superior longitudinal fasciculus. A possible mechanism for the observed FA change may involve increased myelination after training, although this possibility warrants additional investigation.

  18. Sex Differences in Orienting to Pictures with and without Humans : Evidence from the Cardiac Evoked Response (ECR) and the Cortical Long Latency Parietal Positivity (LPP)

    NARCIS (Netherlands)

    Althaus, Monika; Groen, Yvonne; van der Schaft, Lutske; Minderaa, Ruud B.; Tucha, Oliver; Mulder, Lambertus J. M.; Wijers, Albertus A.

    2014-01-01

    OBJECTIVE: This study investigated the effect of social relevance in affective pictures on two orienting responses, i.e. the evoked cardiac response (ECR), and a long latency cortical evoked potential (LPP) and whether this effect would differ between males and females. Assuming that orienting to

  19. Superior digit memory of abacus experts: an event-related functional MRI study.

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    Tanaka, Satoshi; Michimata, Chikashi; Kaminaga, Tatsuro; Honda, Manabu; Sadato, Norihiro

    2002-12-01

    Abacus experts exhibit superior short-term memory for digits, but the underlying neurophysiological mechanism remains unknown. Using event-related fMRI, we examined the brain activity of abacus experts and non-experts during the memory retention period of a delayed match-to-sample task using digits as stimuli. In controls, activity was greater in cortical areas related to verbal working memory, including Broca's area. In contrast, in experts, activity was greater in cortical areas related to visuo-spatial working memory, including the bilateral superior frontal sulcus and superior parietal lobule. This provides neurophysiological evidence that abacus experts utilize a visuo-spatial representation for digit memory.

  20. Functional interaction between right parietal and bilateral frontal cortices during visual search tasks revealed using functional magnetic imaging and transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Amanda Ellison

    Full Text Available The existence of a network of brain regions which are activated when one undertakes a difficult visual search task is well established. Two primary nodes on this network are right posterior parietal cortex (rPPC and right frontal eye fields. Both have been shown to be involved in the orientation of attention, but the contingency that the activity of one of these areas has on the other is less clear. We sought to investigate this question by using transcranial direct current stimulation (tDCS to selectively decrease activity in rPPC and then asking participants to perform a visual search task whilst undergoing functional magnetic resonance imaging. Comparison with a condition in which sham tDCS was applied revealed that cathodal tDCS over rPPC causes a selective bilateral decrease in frontal activity when performing a visual search task. This result demonstrates for the first time that premotor regions within the frontal lobe and rPPC are not only necessary to carry out a visual search task, but that they work together to bring about normal function.

  1. Macrostructural brain changes in patients with longstanding type 1 diabetes mellitus - a cortical thickness analysis study

    DEFF Research Database (Denmark)

    Frøkjær, J B; Brock, C; Søfteland, E

    2013-01-01

    with longstanding (average 24.6 years) type 1 DM and 20 healthy controls were studied in a 3T magnetic resonance scanner. Using an automated surface based cortical segmentation method, cortical thickness was assessed in anatomical regions including total and lobe-wise grey and white matter volumes. Also.......03) and superior parietal gyrus (P=0.008) in patients. The cortical thickness of these regions was not associated with diabetes duration, age at diabetes onset or to HbA1c (all P>0.08). Patients with peripheral neuropathy showed reduced right postcentral gyrus cortical thickness compared to patients without...

  2. Sex differences in orienting to pictures with and without humans: evidence from the cardiac evoked response (ECR and the cortical long latency parietal positivity (LPP.

    Directory of Open Access Journals (Sweden)

    Monika Althaus

    Full Text Available OBJECTIVE: This study investigated the effect of social relevance in affective pictures on two orienting responses, i.e. the evoked cardiac response (ECR, and a long latency cortical evoked potential (LPP and whether this effect would differ between males and females. Assuming that orienting to affective social information is fundamental to experiencing affective empathy, associations between self-report measures of empathy and the two orienting responses were investigated. METHOD: ECRs were obtained from 34 female and 30 male students, and LPPs from 25 female and 27 male students viewing 414 pictures from the International Affective Picture System. Pictures portrayed pleasant, unpleasant and neutral scenes with and without humans. RESULTS: Both the ECR and LPP showed the largest response to pictures with humans in unpleasant situations. For both measures, the responses to pictures with humans correlated with self-report measures of empathy. While we found a greater male than female responsiveness to the pictures without humans in the ECR, a greater female than male responsiveness was observed in the LPP response to pictures with humans. CONCLUSION AND SIGNIFICANCE: The sensitivity of these orienting responses to social relevance and their differential contribution to the prediction of individual differences underline the validity of their combined use in clinical studies investigating individuals with social disabilities.

  3. Sex differences in orienting to pictures with and without humans: evidence from the cardiac evoked response (ECR) and the cortical long latency parietal positivity (LPP).

    Science.gov (United States)

    Althaus, Monika; Groen, Yvonne; van der Schaft, Lutske; Minderaa, Ruud B; Tucha, Oliver; Mulder, Lambertus J M; Wijers, Albertus A

    2014-01-01

    This study investigated the effect of social relevance in affective pictures on two orienting responses, i.e. the evoked cardiac response (ECR), and a long latency cortical evoked potential (LPP) and whether this effect would differ between males and females. Assuming that orienting to affective social information is fundamental to experiencing affective empathy, associations between self-report measures of empathy and the two orienting responses were investigated. ECRs were obtained from 34 female and 30 male students, and LPPs from 25 female and 27 male students viewing 414 pictures from the International Affective Picture System. Pictures portrayed pleasant, unpleasant and neutral scenes with and without humans. Both the ECR and LPP showed the largest response to pictures with humans in unpleasant situations. For both measures, the responses to pictures with humans correlated with self-report measures of empathy. While we found a greater male than female responsiveness to the pictures without humans in the ECR, a greater female than male responsiveness was observed in the LPP response to pictures with humans. The sensitivity of these orienting responses to social relevance and their differential contribution to the prediction of individual differences underline the validity of their combined use in clinical studies investigating individuals with social disabilities.

  4. Reduced parietal activation in cervical dystonia after parietal TMS interleaved with fMRI

    NARCIS (Netherlands)

    de Vries, Paulien M.; de Jong, Bauke M.; Bohning, Daryl E.; Hinson, Vanessa K.; George, Mark S.; Leenders, Klaus L.

    2012-01-01

    Objective: Clinically normal hand movement with altered cerebral activation patterns in cervical dystonia (CD) may imply cerebral adaptation. Since impaired sensorimotor integration appears to play a role in dystonia, left superior parietal cortex modulation with repetitive transcranial magnetic sti

  5. Working memory load influences perceptual ambiguity by competing for fronto-parietal attentional resources.

    Science.gov (United States)

    Intaitė, Monika; Duarte, João Valente; Castelo-Branco, Miguel

    2016-11-01

    A visual stimulus is defined as ambiguous when observers perceive it as having at least two distinct and spontaneously alternating interpretations. Neuroimaging studies suggest an involvement of a right fronto-parietal network regulating the balance between stable percepts and the triggering of alternative interpretations. As spontaneous perceptual reversals may occur even in the absence of attention to these stimuli, we investigated neural activity patterns in response to perceptual changes of ambiguous Necker cube under different amounts of working memory load using a dual-task design. We hypothesized that the same regions that process working memory load are involved in perceptual switching and confirmed the prediction that perceptual reversals led to fMRI responses that linearly depended on load. Accordingly, posterior Superior Parietal Lobule, anterior Prefrontal and Dorsolateral Prefrontal cortices exhibited differential BOLD signal changes in response to perceptual reversals under working memory load. Our results also suggest that the posterior Superior Parietal Lobule may be directly involved in the emergence of perceptual reversals, given that it specifically reflects both perceptual versus real changes and load levels. The anterior Prefrontal and Dorsolateral Prefrontal cortices, showing a significant interaction between reversal levels and load, might subserve a modulatory role in such reversals, in a mirror symmetric way: in the former activation is suppressed by the highest loads, and in the latter deactivation is reduced by highest loads, suggesting a more direct role of the aPFC in reversal generation.

  6. Longitudinal changes in cortical thickness associated with normal aging.

    Science.gov (United States)

    Thambisetty, Madhav; Wan, Jing; Carass, Aaron; An, Yang; Prince, Jerry L; Resnick, Susan M

    2010-10-01

    Imaging studies of anatomic changes in regional gray matter volumes and cortical thickness have documented age effects in many brain regions, but the majority of such studies have been cross-sectional investigations of individuals studied at a single point in time. In this study, using serial imaging assessments of participants in the Baltimore Longitudinal Study of Aging (BLSA), we investigate longitudinal changes in cortical thickness during aging in a cohort of 66 older adults (mean age 68.78; sd. 6.6; range 60-84 at baseline) without dementia. We used the Cortical Reconstruction Using Implicit Surface Evolution CRUISE suite of algorithms to automatically generate a reconstruction of the cortical surface and identified twenty gyral based regions of interest per hemisphere. Using mixed effects regression, we investigated longitudinal changes in these regions over a mean follow-up interval of 8 years. The main finding in this study is that age-related decline in cortical thickness is widespread, but shows an anterior-posterior gradient with frontal and parietal regions, in general, exhibiting greater rates of decline than temporal and occipital. There were fewer regions in the right hemisphere showing statistically significant age-associated longitudinal decreases in mean cortical thickness. Males showed greater rates of decline in the middle frontal, inferior parietal, parahippocampal, postcentral, and superior temporal gyri in the left hemisphere, right precuneus and bilaterally in the superior parietal and cingulate regions. Significant nonlinear changes over time were observed in the postcentral, precentral, and orbitofrontal gyri on the left and inferior parietal, cingulate, and orbitofrontal gyri on the right.

  7. Parietal cortex and representation of the mental Self

    DEFF Research Database (Denmark)

    Lou, Hans C; Luber, Bruce; Crupain, Michael

    2004-01-01

    differential activity in medial prefrontal and medial parietal cortices. With positron-emission tomography, we here show that these medial regions are functionally connected and interact with lateral regions that are activated according to the degree of self-reference. During retrieval of previous judgments...... of Oneself, Best Friend, and the Danish Queen, activation increased in the left lateral temporal cortex and decreased in the right inferior parietal region with decreasing self-reference. Functionally, the former region was preferentially connected to medial prefrontal cortex, the latter to medial parietal....... The medial parietal region may, then, be conceived of as a nodal structure in self-representation, functionally connected to both the right parietal and the medial prefrontal cortices. To determine whether medial parietal cortex in this network is essential for episodic memory retrieval with self...

  8. Aberrant parietal cortex developmental trajectories in girls with Turner syndrome and related visual-spatial cognitive development: a preliminary study.

    Science.gov (United States)

    Green, Tamar; Chromik, Lindsay C; Mazaika, Paul K; Fierro, Kyle; Raman, Mira M; Lazzeroni, Laura C; Hong, David S; Reiss, Allan L

    2014-09-01

    Turner syndrome (TS) arises from partial or complete absence of the X-chromosome in females. Girls with TS show deficits in visual-spatial skills as well as reduced brain volume and surface area in the parietal cortex which supports these cognitive functions. Thus, measuring the developmental trajectory of the parietal cortex and the associated visual-spatial cognition in TS may provide novel insights into critical brain-behavior associations. In this longitudinal study, we acquired structural MRI data and assessed visual-spatial skills in 16 (age: 8.23 ± 2.5) girls with TS and 13 age-matched controls over two time-points. Gray and white matter volume, surface area and cortical thickness were calculated from surfaced based segmentation of bilateral parietal cortices, and the NEPSY Arrows subtest was used to assess visual-spatial ability. Volumetric and cognitive scalars were modeled to obtain estimates of age-related change. The results show aberrant growth of white matter volume (P = 0.011, corrected) and surface area (P = 0.036, corrected) of the left superior parietal regions during childhood in girls with TS. Other parietal sub-regions were significantly smaller in girls with TS at both time-points but did not show different growth trajectories relative to controls. Furthermore, we found that visual-spatial skills showed a widening deficit for girls with TS relative to controls (P = 0.003). Young girls with TS demonstrate an aberrant trajectory of parietal cortical and cognitive development during childhood. Elucidating aberrant neurodevelopmental trajectories in this population is critical for determining specific stages of brain maturation that are particularly dependent on TS-related genetic and hormonal factors. © 2014 Wiley Periodicals, Inc.

  9. Uncertain relational reasoning in the parietal cortex.

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    Ragni, Marco; Franzmeier, Imke; Maier, Simon; Knauff, Markus

    2016-04-01

    The psychology of reasoning is currently transitioning from the study of deductive inferences under certainty to inferences that have degrees of uncertainty in both their premises and conclusions; however, only a few studies have explored the cortical basis of uncertain reasoning. Using transcranial magnetic stimulation (TMS), we show that areas in the right superior parietal lobe (rSPL) are necessary for solving spatial relational reasoning problems under conditions of uncertainty. Twenty-four participants had to decide whether a single presented order of objects agreed with a given set of indeterminate premises that could be interpreted in more than one way. During the presentation of the order, 10-Hz TMS was applied over the rSPL or a sham control site. Right SPL TMS during the inference phase disrupted performance in uncertain relational reasoning. Moreover, we found differences in the error rates between preferred mental models, alternative models, and inconsistent models. Our results suggest that different mechanisms are involved when people reason spatially and evaluate different kinds of uncertain conclusions.

  10. Structural alteration of the dorsal visual network in DLB patients with visual hallucinations: a cortical thickness MRI study.

    Science.gov (United States)

    Delli Pizzi, Stefano; Franciotti, Raffaella; Tartaro, Armando; Caulo, Massimo; Thomas, Astrid; Onofrj, Marco; Bonanni, Laura

    2014-01-01

    Visual hallucinations (VH) represent one of the core features in discriminating dementia with Lewy bodies (DLB) from Alzheimer's Disease (AD). Previous studies reported that in DLB patients functional alterations of the parieto-occipital regions were correlated with the presence of VH. The aim of our study was to assess whether morphological changes in specific cortical regions of DLB could be related to the presence and severity of VH. We performed a cortical thickness analysis on magnetic resonance imaging data in a cohort including 18 DLB patients, 15 AD patients and 14 healthy control subjects. Relatively to DLB group, correlation analysis between the cortical thickness and the Neuropsychiatric Inventory (NPI) hallucination item scores was also performed. Cortical thickness was reduced bilaterally in DLB compared to controls in the pericalcarine and lingual gyri, cuneus, precuneus, superior parietal gyrus. Cortical thinning was found bilaterally in AD compared to controls in temporal cortex including the superior and middle temporal gyrus, part of inferior temporal cortex, temporal pole and insula. Inferior parietal and supramarginal gyri were also affected bilaterally in AD as compared to controls. The comparison between DLB and AD evidenced cortical thinning in DLB group in the right posterior regions including superior parietal gyrus, precuneus, cuneus, pericalcarine and lingual gyri. Furthermore, the correlation analysis between cortical thickness and NPI hallucination item scores showed that the structural alteration in the dorsal visual regions including superior parietal gyrus and precuneus closely correlated with the occurrence and severity of VH. We suggest that structural changes in key regions of the dorsal visual network may play a crucial role in the physiopathology of VH in DLB patients.

  11. Structural alteration of the dorsal visual network in DLB patients with visual hallucinations: a cortical thickness MRI study.

    Directory of Open Access Journals (Sweden)

    Stefano Delli Pizzi

    Full Text Available Visual hallucinations (VH represent one of the core features in discriminating dementia with Lewy bodies (DLB from Alzheimer's Disease (AD. Previous studies reported that in DLB patients functional alterations of the parieto-occipital regions were correlated with the presence of VH. The aim of our study was to assess whether morphological changes in specific cortical regions of DLB could be related to the presence and severity of VH. We performed a cortical thickness analysis on magnetic resonance imaging data in a cohort including 18 DLB patients, 15 AD patients and 14 healthy control subjects. Relatively to DLB group, correlation analysis between the cortical thickness and the Neuropsychiatric Inventory (NPI hallucination item scores was also performed. Cortical thickness was reduced bilaterally in DLB compared to controls in the pericalcarine and lingual gyri, cuneus, precuneus, superior parietal gyrus. Cortical thinning was found bilaterally in AD compared to controls in temporal cortex including the superior and middle temporal gyrus, part of inferior temporal cortex, temporal pole and insula. Inferior parietal and supramarginal gyri were also affected bilaterally in AD as compared to controls. The comparison between DLB and AD evidenced cortical thinning in DLB group in the right posterior regions including superior parietal gyrus, precuneus, cuneus, pericalcarine and lingual gyri. Furthermore, the correlation analysis between cortical thickness and NPI hallucination item scores showed that the structural alteration in the dorsal visual regions including superior parietal gyrus and precuneus closely correlated with the occurrence and severity of VH. We suggest that structural changes in key regions of the dorsal visual network may play a crucial role in the physiopathology of VH in DLB patients.

  12. Patterns of cortical thinning in nondemented Parkinson's disease patients

    Science.gov (United States)

    Uribe, Carme; Segura, Barbara; Baggio, Hugo Cesar; Abos, Alexandra; Marti, Maria Jose; Valldeoriola, Francesc; Compta, Yaroslau; Bargallo, Nuria

    2016-01-01

    ABSTRACT Background Clinical variability in the Parkinson's disease phenotype suggests the existence of disease subtypes. We investigated whether distinct anatomical patterns of atrophy can be identified in Parkinson's disease using a hypothesis‐free, data‐driven approach based on cortical thickness data. Methods T1‐weighted 3‐tesla MRI and a comprehensive neuropsychological assessment were performed in a sample of 88 nondemented Parkinson's disease patients and 31 healthy controls. We performed a hierarchical cluster analysis of imaging data using Ward's linkage method. A general linear model with cortical thickness data was used to compare clustering groups. Results We observed 3 patterns of cortical thinning in patients when compared with healthy controls. Pattern 1 (n = 30, 34.09%) consisted of cortical atrophy in bilateral precentral gyrus, inferior and superior parietal lobules, cuneus, posterior cingulate, and parahippocampal gyrus. These patients showed worse cognitive performance when compared with controls and the other 2 patterns. Pattern 2 (n = 29, 32.95%) consisted of cortical atrophy involving occipital and frontal as well as superior parietal areas and included patients with younger age at onset. Finally, in pattern 3 (n = 29, 32.95%), there was no detectable cortical thinning. Patients in the 3 patterns did not differ in disease duration, motor severity, dopaminergic medication doses, or presence of mild cognitive impairment. Conclusions Three cortical atrophy subtypes were identified in nondemented Parkinson's disease patients: (1) parieto‐temporal pattern of atrophy with worse cognitive performance, (2) occipital and frontal cortical atrophy and younger disease onset, and (3) patients without detectable cortical atrophy. These findings may help identify prognosis markers in Parkinson's disease. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement

  13. Association of dorsal inferior frontooccipital fasciculus fibers in the deep parietal lobe with both reading and writing processes: a brain mapping study.

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    Motomura, Kazuya; Fujii, Masazumi; Maesawa, Satoshi; Kuramitsu, Shunichiro; Natsume, Atsushi; Wakabayashi, Toshihiko

    2014-07-01

    Alexia and agraphia are disorders common to the left inferior parietal lobule, including the angular and supramarginal gyri. However, it is still unclear how these cortical regions interact with other cortical sites and what the most important white matter tracts are in relation to reading and writing processes. Here, the authors present the case of a patient who underwent an awake craniotomy for a left inferior parietal lobule glioma using direct cortical and subcortical electrostimulation. The use of subcortical stimulation allowed identification of the specific white matter tracts associated with reading and writing. These tracts were found as portions of the dorsal inferior frontooccipital fasciculus (IFOF) fibers in the deep parietal lobe that are responsible for connecting the frontal lobe to the superior parietal lobule. These findings are consistent with previous diffusion tensor imaging tractography and functional MRI studies, which suggest that the IFOF may play a role in the reading and writing processes. This is the first report of transient alexia and agraphia elicited through intraoperative direct subcortical electrostimulation, and the findings support the crucial role of the IFOF in reading and writing.

  14. Forced arm use is superior to voluntary training for motor recovery and brain plasticity after cortical ischemia in rats.

    Science.gov (United States)

    Schneider, Armin; Rogalewski, Andreas; Wafzig, Oliver; Kirsch, Friederike; Gretz, Norbert; Krüger, Carola; Diederich, Kai; Pitzer, Claudia; Laage, Rico; Plaas, Christian; Vogt, Gerhard; Minnerup, Jens; Schäbitz, Wolf-Rüdiger

    2014-02-14

    Both the immobilization of the unaffected arm combined with physical therapy (forced arm use, FAU) and voluntary exercise (VE) as model for enriched environment are promising approaches to enhance recovery after stroke. The genomic mechanisms involved in long-term plasticity changes after different means of rehabilitative training post-stroke are largely unexplored. The present investigation explored the effects of these physical therapies on behavioral recovery and molecular markers of regeneration after experimental ischemia. 42 Wistar rats were randomly treated with either forced arm use (FAU, 1-sleeve plaster cast onto unaffected limb at 8/10 days), voluntary exercise (VE, connection of a freely accessible running wheel to cage), or controls with no access to a running wheel for 10 days starting at 48 hours after photothrombotic stroke of the sensorimotor cortex. Functional outcome was measured using sensorimotor test before ischemia, after ischemia, after the training period of 10 days, at 3 and 4 weeks after ischemia. Global gene expression changes were assessed from the ipsi- and contralateral cortex and the hippocampus. FAU-treated animals demonstrated significantly improved functional recovery compared to the VE-treated group. Both were superior to cage control. A large number of genes are altered by both training paradigms in the ipsi- and contralateral cortex and the hippocampus. Overall, the extent of changes observed correlated well with the functional recovery obtained. One category of genes overrepresented in the gene set is linked to neuronal plasticity processes, containing marker genes such as the NMDA 2a receptor, PKC ζ, NTRK2, or MAP 1b. We show that physical training after photothrombotic stroke significantly and permanently improves functional recovery after stroke, and that forced arm training is clearly superior to voluntary running training. The behavioral outcomes seen correlate with patterns and extent of gene expression changes in all

  15. Gelastic seizures involving the left parietal lobe.

    Science.gov (United States)

    Machado, René Andrade; Astencio, Adriana Goicoechea

    2012-01-01

    Gelastic seizures have been described in various epilepsies arising from the temporal or frontal lobes, although the most commonly encountered form is related to the presence of a hypothalamic hamartoma. We describe a patient with gelastic seizures involving the left parietal lobe. Our patient, an 8-year-old girl, underwent interictal video/EEG monitoring and MRI. The seizures consisted of brief staring followed by smiling and laughing. Electroencephalography during the gelastic seizures showed rhythmic spikes and waves in the left parietal lobe. MRI revealed the characteristic features of focal cortical dysplasia. Our findings suggest that the left parietal lobe may actively participate in the particular epileptogenic network generating gelastic seizures. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Parietal cell vagotomy.

    Science.gov (United States)

    Cumberland, V H; Coupland, G A

    1975-07-12

    In a series of 100 consecutive patients who had parietal cell vagotomy performed, no drainage procedure was performed in 56 while 44 were drained. Dumping was significantly less in those who were not drained. All patients were tested for adequacy of vagotomy and for function of the nerve of Latarget at operation. Four patients have had further operations, two for proven recurrent ulcers. Parietal cell vagotomy has given excellent clinical results in this group of patients.

  17. Abnormalities of fixation, saccade and pursuit in posterior cortical atrophy.

    Science.gov (United States)

    Shakespeare, Timothy J; Kaski, Diego; Yong, Keir X X; Paterson, Ross W; Slattery, Catherine F; Ryan, Natalie S; Schott, Jonathan M; Crutch, Sebastian J

    2015-07-01

    whose frequency correlated significantly with generalized reductions in cortical thickness. Patients with both posterior cortical atrophy and typical Alzheimer's disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in posterior cortical atrophy, and highlights multiple aspects of saccadic performance which distinguish posterior cortical atrophy from typical Alzheimer's disease. We suggest the posterior cortical atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in posterior cortical atrophy and many other patients with dementia-related visual impairment.

  18. Right parietal dominance in spatial egocentric discrimination.

    Science.gov (United States)

    Loayza, F R; Fernández-Seara, M A; Aznárez-Sanado, M; Pastor, M A

    2011-03-15

    Egocentric tactile perception is crucial for skilled hand motor control. In order to better understand the brain functional underpinnings related to this basic sensorial perception, we performed a tactile perception functional magnetic resonance imaging (fMRI) experiment with two aims. The first aim consisted of characterizing the neural substrate of two types of egocentric tactile discrimination: the spatial localization (SLD) and simultaneity succession discrimination (SSD) in both hands to define hemispheric dominance for these tasks. The second goal consisted of characterizing the brain activation related to the spatial attentional load, the functional changes and their connectivity patterns induced by the psychometric performance (PP) during SLD. We used fMRI in 25 right-handed volunteers, applying pairs of sinusoidal vibratory stimuli on eight different positions in the palmar surface of both hands. Subjects were required either to identify the stimulus location with respect to an imaginary midline (SLD), to discriminate the simultaneity or succession of a stimuli pair (SSD) or to simply respond to stimulus detection. We found a fronto-parietal network for SLD and frontal network for SSD. During SLD we identified right hemispheric dominance with increased BOLD activation and functional interaction of the right supramarginal gyrus with contralateral intra-parietal sulcus for right and left hand independently. Brain activity correlated to spatial attentional load was found in bilateral structures of intra-parietal sulcus, precuneus extended to superior parietal lobule, pre-supplementary motor area, frontal eye fields and anterior insulae for both hands. We suggest that the right supramarginal gyrus and its interaction with intra-parietal lobule may play a pivotal role in the phenomenon of tactile neglect in right fronto-parietal lesions. Copyright © 2010 Elsevier Inc. All rights reserved.

  19. Safe Harvesting of Outer Table Parietal Bone Grafts Using an Oscillating Saw and a Bone Scraper : A Refinement of Technique for Harvesting Cortical and "Cancellous"-Like Calvarial Bone

    NARCIS (Netherlands)

    Schortinghuis, Jurjen; Putters, Thomas F.; Raghoebar, Gerry M.

    2012-01-01

    Calvarial bone is a readily available source of bone for preimplantation augmentation procedures of the alveolar process. However, the calvaria consist mostly of cortical bone, and cancellous bone of the diploic space is scarce. A bone scraper (Safescraper Twist; META, Reggio Emilia, Italy) was used

  20. Parcellation of left parietal tool representations by functional connectivity

    Science.gov (United States)

    Garcea, Frank E.; Z. Mahon, Bradford

    2014-01-01

    Manipulating a tool according to its function requires the integration of visual, conceptual, and motor information, a process subserved in part by left parietal cortex. How these different types of information are integrated and how their integration is reflected in neural responses in the parietal lobule remains an open question. Here, participants viewed images of tools and animals during functional magnetic resonance imaging (fMRI). K-means clustering over time series data was used to parcellate left parietal cortex into subregions based on functional connectivity to a whole brain network of regions involved in tool processing. One cluster, in the inferior parietal cortex, expressed privileged functional connectivity to the left ventral premotor cortex. A second cluster, in the vicinity of the anterior intraparietal sulcus, expressed privileged functional connectivity with the left medial fusiform gyrus. A third cluster in the superior parietal lobe expressed privileged functional connectivity with dorsal occipital cortex. Control analyses using Monte Carlo style permutation tests demonstrated that the clustering solutions were outside the range of what would be observed based on chance ‘lumpiness’ in random data, or mere anatomical proximity. Finally, hierarchical clustering analyses were used to formally relate the resulting parcellation scheme of left parietal tool representations to previous work that has parcellated the left parietal lobule on purely anatomical grounds. These findings demonstrate significant heterogeneity in the functional organization of manipulable object representations in left parietal cortex, and outline a framework that generates novel predictions about the causes of some forms of upper limb apraxia. PMID:24892224

  1. Brain volumes and regional cortical thickness in young females with anorexia nervosa.

    Science.gov (United States)

    Fuglset, Tone Seim; Endestad, Tor; Hilland, Eva; Bang, Lasse; Tamnes, Christian Krog; Landrø, Nils Inge; Rø, Øyvind

    2016-11-16

    Anorexia nervosa (AN) is a severe mental illness, with an unknown etiology. Magnetic resonance imaging studies show reduced brain volumes and cortical thickness in patients compared to healthy controls. However, findings are inconsistent, especially concerning the anatomical location and extent of the differences. The purpose of this study was to estimate and compare brain volumes and regional cortical thickness in young females with AN and healthy controls. Magnetic resonance imaging data was acquired from young females with anorexia nervosa (n = 23) and healthy controls (n = 28). Two different scanner sites were used. BMI varied from 13.5 to 20.7 within the patient group, and 11 patients had a BMI > 17.5. FreeSurfer was used to estimate brain volumes and regional cortical thickness. There were no differences between groups in total cerebral cortex volume, white matter volume, or lateral ventricle volume. There were also no volume differences in subcortical grey matter structures. However the results showed reduced cortical thickness bilaterally in the superior parietal gyrus, and in the right inferior parietal and superior frontal gyri. The functional significance of the findings is undetermined as the majority of the included patients was already partially weight-restored. We discuss whether these regions could be related to predisposing factors of the illness, or whether they are regions that are more vulnerable to starvation, malnutrition or associated processes in AN.

  2. Cortical gyrification and sulcal spans in early stage Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Tao Liu

    Full Text Available Alzheimer's disease (AD is characterized by an insidious onset of progressive cerebral atrophy and cognitive decline. Previous research suggests that cortical folding and sulcal width are associated with cognitive function in elderly individuals, and the aim of the present study was to investigate these morphological measures in patients with AD. The sample contained 161 participants, comprising 80 normal controls, 57 patients with very mild AD, and 24 patients with mild AD. From 3D T1-weighted brain scans, automated methods were used to calculate an index of global cortex gyrification and the width of five individual sulci: superior frontal, intra-parietal, superior temporal, central, and Sylvian fissure. We found that global cortex gyrification decreased with increasing severity of AD, and that the width of all individual sulci investigated other than the intra-parietal sulcus was greater in patients with mild AD than in controls. We also found that cognitive functioning, as assessed by Mini-Mental State Examination (MMSE scores, decreased as global cortex gyrification decreased. MMSE scores also decreased in association with a widening of all individual sulci investigated other than the intra-parietal sulcus. The results suggest that abnormalities of global cortex gyrification and regional sulcal span are characteristic of patients with even very mild AD, and could thus facilitate the early diagnosis of this condition.

  3. Parietal lobe epilepsy.

    Science.gov (United States)

    Salanova, Vicenta

    2012-10-01

    Patients with parietal lobe epilepsy (PLE) exhibit an electroclinical epilepsy syndrome that is rarely seen even at large epilepsy centers. Clinically, most patients with PLE exhibit a somatosensory aura that may include painful dysesthesias, though vertigo, aphasia, disturbances of one's body image also occur, when ictal propagation occurs from the parietal lobe to the supplementary motor area, hypermotor manifestations are noted. When temporolimbic propagation occurs, complex visual or auditory hallucinations and automatisms may appear. Scalp electroencephalogram (EEG) is often nonlocalizing. Ictal EEG is rarely localizing in PLE, and invasive EEG is often required for definitive localization and functional mapping. Recent advances in clinical neurophysiology during the evaluation of patients with refractory partial epilepsy include Ictal magnetic source imaging (MSI). Combined EEG and functional magnetic resonance imaging (EEG-fMRI) may be useful for patients with PLE to refine the localization in patients undergoing a presurgical evaluation. High-frequency oscillations (HFOs) are more concentrated inside the seizure onset zone (SOZ), indicating that they may be used as interictal scalp EEG biomarker for the SOZ. When medical therapy fails, resective epilepsy surgery can result in seizure freedom or significant reduction especially when a lesion is present.

  4. Parietal cheiro-oral syndrome.

    Science.gov (United States)

    Yasuda, Y; Watanabe, T; Ogura, A

    2000-12-01

    Cheiro-oral syndrome due to a parietal lesion has been reported in conjuction with a brain tumor, infarction and migraine. Only six reports of cheiro-oral syndrome due to a parietal infarction have been reported to date. We treated a 45-year-old woman with cheiro-oral syndrome due to a parietal infarction. Her sensory disturbance was characterized by paresthesia in the lower face and hand on the left side, and severe involvement of stereognosis and graphesthesia in the left hand. The pathogenesis of parietal cheiro-oral syndrome is discussed.

  5. Semantic retrieval during overt picture description: Left anterior temporal or the parietal lobe?

    Science.gov (United States)

    Geranmayeh, Fatemeh; Leech, Robert; Wise, Richard J S

    2015-09-01

    Retrieval of semantic representations is a central process during overt speech production. There is an increasing consensus that an amodal semantic 'hub' must exist that draws together modality-specific representations of concepts. Based on the distribution of atrophy and the behavioral deficit of patients with the semantic variant of fronto-temporal lobar degeneration, it has been proposed that this hub is localized within both anterior temporal lobes (ATL), and is functionally connected with verbal 'output' systems via the left ATL. An alternative view, dating from Geschwind's proposal in 1965, is that the angular gyrus (AG) is central to object-based semantic representations. In this fMRI study we examined the connectivity of the left ATL and parietal lobe (PL) with whole brain networks known to be activated during overt picture description. We decomposed each of these two brain volumes into 15 regions of interest (ROIs), using independent component analysis. A dual regression analysis was used to establish the connectivity of each ROI with whole brain-networks. An ROI within the left anterior superior temporal sulcus (antSTS) was functionally connected to other parts of the left ATL, including anterior ventromedial left temporal cortex (partially attenuated by signal loss due to susceptibility artifact), a large left dorsolateral prefrontal region (including 'classic' Broca's area), extensive bilateral sensory-motor cortices, and the length of both superior temporal gyri. The time-course of this functionally connected network was associated with picture description but not with non-semantic baseline tasks. This system has the distribution expected for the production of overt speech with appropriate semantic content, and the auditory monitoring of the overt speech output. In contrast, the only left PL ROI that showed connectivity with brain systems most strongly activated by the picture-description task, was in the superior parietal lobe (supPL). This region

  6. Abnormal temporal and parietal magnetic activations during the early stages of theory of mind in schizophrenic patients.

    Science.gov (United States)

    Vistoli, Damien; Brunet-Gouet, Eric; Lemoalle, Amelia; Hardy-Baylé, Marie-Christine; Passerieux, Christine

    2011-01-01

    Schizophrenia is associated with abnormal cortical activation during theory of mind (ToM), as demonstrated by several fMRI or PET studies. Electrical and temporal characteristics of these abnormalities, especially in the early stages, remain unexplored. Nineteen medicated schizophrenic patients and 21 healthy controls underwent magnetoencephalography (MEG) recording to measure brain response evoked by nonverbal stimuli requiring mentalizing. Three conditions based on comic-strips were contrasted: attribution of intentions to others (AI), physical causality with human characters (PCCH), and physical causality with objects (PCOB). Minimum norm localization was performed in order to select regions of interest (ROIs) within bilateral temporal and parietal regions that showed significant ToM-related activations in the control group. Time-courses of each ROI were compared across group and condition. Reduced cortical activation within the 200 to 600 ms time-window was observed in the selected regions in patients. Significant group by condition interactions (i.e., reduced modulation in patients) were found in right posterior superior temporal sulcus, right temporoparietal junction, and right inferior parietal lobule during attribution of intentions. As in healthy controls, the presence of characters elicited activation in patients' left posterior temporal regions and temporoparietal junction. No group difference on evoked responses' latencies in AI was found. In conclusion, ToM processes in the early stages are functionally impaired in schizophrenia. MEG provides a promising means to refine our knowledge on schizophrenic social cognitive disorders.

  7. Parietal Lobe Volume Deficits in Adolescents with Schizophrenia and Adolescents with Cannabis Use Disorders

    Science.gov (United States)

    Kumra, Sanjiv; Robinson, Paul; Tambyraja, Rabindra; Jensen, Daniel; Schimunek, Caroline; Houri, Alaa; Reis, Tiffany; Lim, Kelvin

    2012-01-01

    Objective: In early-onset schizophrenia (EOS), the earliest structural brain volumetric abnormalities appear in the parietal cortices. Early exposure to cannabis may represent an environmental risk factor for developing schizophrenia. This study characterized cerebral cortical gray matter structure in adolescents in regions of interest (ROIs) that…

  8. Parietal Lobe Volume Deficits in Adolescents with Schizophrenia and Adolescents with Cannabis Use Disorders

    Science.gov (United States)

    Kumra, Sanjiv; Robinson, Paul; Tambyraja, Rabindra; Jensen, Daniel; Schimunek, Caroline; Houri, Alaa; Reis, Tiffany; Lim, Kelvin

    2012-01-01

    Objective: In early-onset schizophrenia (EOS), the earliest structural brain volumetric abnormalities appear in the parietal cortices. Early exposure to cannabis may represent an environmental risk factor for developing schizophrenia. This study characterized cerebral cortical gray matter structure in adolescents in regions of interest (ROIs) that…

  9. Double dissociation between motor and visual imagery in the posterior parietal cortex.

    Science.gov (United States)

    Pelgrims, Barbara; Andres, Michael; Olivier, Etienne

    2009-10-01

    Because motor imagery (MI) and visual imagery (VI) are influenced differently by factors such as biomechanical constraints or stimulus size, it is conceivable that they rely on separate processes, possibly involving distinct cortical networks, a view corroborated by neuroimaging and neuropsychological studies. In the posterior parietal cortex, it has been suggested that the superior parietal lobule (SPL) underlies VI, whereas MI relies on the supramarginalis gyrus (SMG). However, because several brain imaging studies have also shown an overlap of activations in SPL and SMG during VI or MI, the question arises as to which extent these 2 subregions really contribute to distinct imagery processes. To address this issue, we used repetitive transcranial magnetic stimulation to induce virtual lesions of either SMG or SPL in subjects performing a MI (hand drawing rotation) or a VI (letter rotation) task. Whatever hemisphere was stimulated, SMG lesions selectively altered MI, whereas SPL lesions only affected VI, demonstrating a double dissociation between MI and VI. Because these deficits were not influenced by the angular distance of the stimuli, we suggest that SMG and SPL are involved in the reenactment of the motor and visual representations, respectively, and not in mental rotation processes per se.

  10. Development of a superior frontal-intraparietal network for visuo-spatial working memory.

    Science.gov (United States)

    Klingberg, Torkel

    2006-01-01

    Working memory capacity increases throughout childhood and adolescence, which is important for the development of a wide range of cognitive abilities, including complex reasoning. The spatial-span task, in which subjects retain information about the order and position of a number of objects, is a sensitive task to measure development of spatial working memory. This review considers results from previous neuroimaging studies investigating the neural correlates of this development. Older children and adolescents, with higher capacity, have been found to have higher brain activity in the intraparietal cortex and in the posterior part of the superior frontal sulcus, during the performance of working memory tasks. The structural maturation of white matter has been investigated by diffusion tensor magnetic resonance imaging (DTI). This has revealed several regions in the frontal lobes in which white matter maturation is correlated with the development of working memory. Among these is a superior fronto-parietal white matter region, located close to the grey matter regions that are implicated in the development of working memory. Furthermore, the degree of white matter maturation is positively correlated with the degree of cortical activation in the frontal and parietal regions. This suggests that during childhood and adolescence, there is development of networks related to specific cognitive functions, such as visuo-spatial working memory. These networks not only consist of cortical areas but also the white matter tracts connecting them. For visuo-spatial working memory, this network could consist of the superior frontal and intraparietal cortex.

  11. Apraxia and the Parietal Lobes

    Science.gov (United States)

    Goldenberg, Georg

    2009-01-01

    The widely held belief in a central role of left parietal lesions for apraxia can be traced back to Liepmann's model of a posterior to anterior stream converting mental images of intended action into motor execution. Although this model has undergone significant changes, its modern descendants still attribute the parietal contribution to the…

  12. Parietal intraparenchymal Schwannoma: case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Hwan; Chung, Tae Woong; Yoon, Woong; Jeong, Gwang Woo; Kang, Heoung Keun [Chonnam National University Hospital, Kwangju (Korea, Republic of)

    2008-10-15

    We report a case of an intraparenchymal schwannoma of the left parietal lobe. A 51-year-old woman was admitted to our hospital with complaints of intermittent headaches. Computed tomography and magnetic resonance images revealed a 1.3 cm sized intra-axial homogeneous enhancing mass in the left parietal lobe. The lesion was pathologically confirmed to be a schwannoma.

  13. Effect of Kangxin Capsule(康欣胶囊) on the Expression of Nerve Growth Factors in Parietal Lobe of Cortex and Hippocampus CA1 Area of Vascular Dementia Model Rats

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To observe the effect of Kangxin Capsule (康欣胶囊, KXC) on the expression of nerve growth factor (NGF) as well as the morphology and amount of nerve synapse in the cortical parietal lobe and hippocampus CA1 area of vascular dementia (VD) model rats. Methods: The model rats of VD made by photochemical reaction technique were randomly divided into five groups: the model group (MG), the high-dose, middle-dose and low-dose KXC groups (HDG, MDG and LDG), and the Western medicine hydergin control group (WMG). They were treated respectively with distilled water, high, middle and low dosage of KXC suspended liquid, and hydergin for a month. Besides, a blank group consisting of normal (non-model)rats was set up for control (CG). The ultrastructure of nerve synapse in the cortical parietal lobe and hippocampus CA1 area of the rats were observed and its density estimated. The condition of NGF positive neurons in the above-mentioned two regions were also observed by immunohistochemical stain. Results: All the KXC or hydergin treated groups demonstrated a normal amount of nerve synapse with integral structure in the cortical parietal lobe and hippocampus CA1 area, which approached that in the CG and was superior to that in the MG. Also, the NGF positive neuron in all the treated groups was much more than that in MG with significant difference ( P<0.01 ), approaching to that in the CG. Conclusion: KXC could elevate the expression of NGF in the cortical parietal lobe and hippocampus CA1 area, preserve the number and morphology of synapse,thus to protect the function of nerve system from ischemic injury.

  14. Fronto-Parietal Contributions to Phonological Processes in Successful Artificial Grammar Learning

    Science.gov (United States)

    Goranskaya, Dariya; Kreitewolf, Jens; Mueller, Jutta L.; Friederici, Angela D.; Hartwigsen, Gesa

    2016-01-01

    Sensitivity to regularities plays a crucial role in the acquisition of various linguistic features from spoken language input. Artificial grammar learning paradigms explore pattern recognition abilities in a set of structured sequences (i.e., of syllables or letters). In the present study, we investigated the functional underpinnings of learning phonological regularities in auditorily presented syllable sequences. While previous neuroimaging studies either focused on functional differences between the processing of correct vs. incorrect sequences or between different levels of sequence complexity, here the focus is on the neural foundation of the actual learning success. During functional magnetic resonance imaging (fMRI), participants were exposed to a set of syllable sequences with an underlying phonological rule system, known to ensure performance differences between participants. We expected that successful learning and rule application would require phonological segmentation and phoneme comparison. As an outcome of four alternating learning and test fMRI sessions, participants split into successful learners and non-learners. Relative to non-learners, successful learners showed increased task-related activity in a fronto-parietal network of brain areas encompassing the left lateral premotor cortex as well as bilateral superior and inferior parietal cortices during both learning and rule application. These areas were previously associated with phonological segmentation, phoneme comparison, and verbal working memory. Based on these activity patterns and the phonological strategies for rule acquisition and application, we argue that successful learning and processing of complex phonological rules in our paradigm is mediated via a fronto-parietal network for phonological processes. PMID:27877120

  15. Fronto-parietal contributions to phonological processes in successful artificial grammar learning

    Directory of Open Access Journals (Sweden)

    Dariya Goranskaya

    2016-11-01

    Full Text Available Sensitivity to regularities plays a crucial role in the acquisition of various linguistic features from spoken language input. Artificial grammar (AG learning paradigms explore pattern recognition abilities in a set of structured sequences (i.e. of syllables or letters. In the present study, we investigated the functional underpinnings of learning phonological regularities in auditorily presented syllable sequences. While previous neuroimaging studies either focused on functional differences between the processing of correct vs. incorrect sequences or between different levels of sequence complexity, here the focus is on the neural foundation of the actual learning success. During functional magnetic resonance imaging (fMRI, participants were exposed to a set of syllable sequences with an underlying phonological rule system, known to ensure performance differences between participants. We expected that successful learning and rule application would require phonological segmentation and phoneme comparison. As an outcome of four alternating learning and test fMRI sessions, participants split into successful learners and non-learners. Relative to non-learners, successful learners showed increased task-related activity in a fronto-parietal network of brain areas encompassing the left lateral premotor cortex as well as bilateral superior and inferior parietal cortices during both learning and rule application. These areas were previously associated with phonological segmentation, phoneme comparison and verbal working memory. Based on these activity patterns and the phonological strategies for rule acquisition and application, we argue that successful learning and processing of complex phonological rules in our paradigm is mediated via a fronto-parietal network for phonological processes.

  16. Genetic associations between intelligence and cortical thickness emerge at the start of puberty.

    Science.gov (United States)

    Brouwer, Rachel M; van Soelen, Inge L C; Swagerman, Suzanne C; Schnack, Hugo G; Ehli, Erik A; Kahn, René S; Hulshoff Pol, Hilleke E; Boomsma, Dorret I

    2014-08-01

    Cognitive abilities are related to (changes in) brain structure during adolescence and adulthood. Previous studies suggest that associations between cortical thickness and intelligence may be different at different ages. As both intelligence and cortical thickness are heritable traits, the question arises whether the association between cortical thickness development and intelligence is due to genes influencing both traits. We study this association in a longitudinal sample of young twins. Intelligence was assessed by standard IQ tests at age 9 in 224 twins, 190 of whom also underwent structural magnetic resonance imaging (MRI). Three years later at age 12, 177/125 twins returned for a follow-up measurement of intelligence/MRI scanning, respectively. We investigated whether cortical thickness was associated with intelligence and if so, whether this association was driven by genes. At age 9, there were no associations between cortical thickness and intelligence. At age 12, a negative relationship emerged. This association was mainly driven by verbal intelligence, and manifested itself most prominently in the left hemisphere. Cortical thickness and intelligence were explained by the same genes. As a post hoc analysis, we tested whether a specific allele (rs6265; Val66Met in the BDNF gene) contributed to this association. Met carriers showed lower intelligence and a thicker cortex, but only the association between the BDNF genotype and cortical thickness in the left superior parietal gyrus reached significance. In conclusion, it seems that brain areas contributing to (verbal) intellectual performance are specializing under the influence of genes around the onset of puberty.

  17. Sylvian Fissure and Parietal Anatomy in Children with Autism Spectrum Disorder

    Science.gov (United States)

    Knaus, Tracey A.; Tager-Flusberg, Helen; Foundas, Anne L.

    2012-01-01

    Autism spectrum disorder (ASD) is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF) and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7–14 years), matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions. PMID:22713374

  18. Sylvian Fissure and Parietal Anatomy in Children with Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Tracey A. Knaus

    2012-01-01

    Full Text Available Autism spectrum disorder (ASD is characterized by deficits in social functioning and language and communication, with restricted interests or stereotyped behaviors. Anatomical differences have been found in the parietal cortex in children with ASD, but parietal subregions and associations between Sylvian fissure (SF and parietal anatomy have not been explored. In this study, SF length and anterior and posterior parietal volumes were measured on MRI in 30 right-handed boys with ASD and 30 right-handed typically developing boys (7–14 years, matched on age and non-verbal IQ. There was leftward SF and anterior parietal asymmetry, and rightward posterior parietal asymmetry, across groups. There were associations between SF and parietal asymmetries, with slight group differences. Typical SF asymmetry was associated with typical anterior and posterior parietal asymmetry, in both groups. In the atypical SF asymmetry group, controls had atypical parietal asymmetry, whereas in ASD there were more equal numbers of individuals with typical as atypical anterior parietal asymmetry. We did not find significant anatomical-behavioral associations. Our findings of more individuals in the ASD group having a dissociation between cortical asymmetries warrants further investigation of these subgroups and emphasizes the importance of investigating anatomical relationships in addition to group differences in individual regions.

  19. Body and movement: consciousness in the parietal lobes.

    Science.gov (United States)

    Daprati, Elena; Sirigu, Angela; Nico, Daniele

    2010-02-01

    A critical issue related to the notion of identity concerns our ability to discriminate between internally and externally generated stimuli. This basic mechanism likely relies on perceptual and motor information, and requires that both motor plans and the resulting activity be continuously mapped on a reliable body representation. It has been widely demonstrated that the parietal cortices of the two hemispheres play a crucial role, albeit differently specialized, in both monitoring internal representation of our own actions and sustaining body representation. Ample neuropsychological evidence indicates that while damage to the left parietal cortex affects the ability to generate and/or monitor an internal model of one's own movement, lesions of the right parietal lobe are largely responsible for severe perturbations of the internal representation of one's own body. In the present paper, we discuss the processes involved in body perception and self-recognition and propose a tentative model describing how the right and left parietal cortices contribute in integrating various sources of information to produce the unique, elementary experience of one's own body in motion. The ecological value of this process in constructing identity and autobiographical experience will be discussed.

  20. Functional differences in epigenetic modulators-superiority of mercaptoacetamide-based histone deacetylase inhibitors relative to hydroxamates in cortical neuron neuroprotection studies.

    Science.gov (United States)

    Kozikowski, Alan P; Chen, Yufeng; Gaysin, Arsen; Chen, Bin; D'Annibale, Melissa A; Suto, Carla M; Langley, Brett C

    2007-06-28

    We compare the ability of two structurally different classes of epigenetic modulators, namely, histone deacetylase (HDAC) inhibitors containing either a hydroxamate or a mercaptoacetamide as the zinc binding group, to protect cortical neurons in culture from oxidative stress-induced death. This study reveals that some of the mercaptoacetamide-based HDAC inhibitors are fully protective, whereas the hydroxamates show toxicity at higher concentrations. Our present results appear to be consistent with the possibility that the mercaptoacetamide-based HDAC inhibitors interact with a different subset of the HDAC isozymes [less activity at HDAC1 and 2 correlates with less inhibitor toxicity], or alternatively, are interacting selectively with only the cytoplasmic HDACs that are crucial for protection from oxidative stress.

  1. Longitudinal changes in cortical thickness in autism and typical development

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    Prigge, Molly B. D.; Nielsen, Jared A.; Froehlich, Alyson L.; Abildskov, Tracy J.; Anderson, Jeffrey S.; Fletcher, P. Thomas; Zygmunt, Kristen M.; Travers, Brittany G.; Lange, Nicholas; Alexander, Andrew L.; Bigler, Erin D.; Lainhart, Janet E.

    2014-01-01

    The natural history of brain growth in autism spectrum disorders remains unclear. Cross-sectional studies have identified regional abnormalities in brain volume and cortical thickness in autism, although substantial discrepancies have been reported. Preliminary longitudinal studies using two time points and small samples have identified specific regional differences in cortical thickness in the disorder. To clarify age-related trajectories of cortical development, we examined longitudinal changes in cortical thickness within a large mixed cross-sectional and longitudinal sample of autistic subjects and age- and gender-matched typically developing controls. Three hundred and forty-five magnetic resonance imaging scans were examined from 97 males with autism (mean age = 16.8 years; range 3–36 years) and 60 males with typical development (mean age = 18 years; range 4–39 years), with an average interscan interval of 2.6 years. FreeSurfer image analysis software was used to parcellate the cortex into 34 regions of interest per hemisphere and to calculate mean cortical thickness for each region. Longitudinal linear mixed effects models were used to further characterize these findings and identify regions with between-group differences in longitudinal age-related trajectories. Using mean age at time of first scan as a reference (15 years), differences were observed in bilateral inferior frontal gyrus, pars opercularis and pars triangularis, right caudal middle frontal and left rostral middle frontal regions, and left frontal pole. However, group differences in cortical thickness varied by developmental stage, and were influenced by IQ. Differences in age-related trajectories emerged in bilateral parietal and occipital regions (postcentral gyrus, cuneus, lingual gyrus, pericalcarine cortex), left frontal regions (pars opercularis, rostral middle frontal and frontal pole), left supramarginal gyrus, and right transverse temporal gyrus, superior parietal lobule, and

  2. Cognitive signals for brain-machine interfaces in posterior parietal cortex include continuous 3D trajectory commands.

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    Hauschild, Markus; Mulliken, Grant H; Fineman, Igor; Loeb, Gerald E; Andersen, Richard A

    2012-10-16

    Cortical neural prosthetics extract command signals from the brain with the goal to restore function in paralyzed or amputated patients. Continuous control signals can be extracted from the motor cortical areas, whereas neural activity from posterior parietal cortex (PPC) can be used to decode cognitive variables related to the goals of movement. Because typical activities of daily living comprise both continuous control tasks such as reaching, and tasks benefiting from discrete control such as typing on a keyboard, availability of both signals simultaneously would promise significant increases in performance and versatility. Here, we show that PPC can provide 3D hand trajectory information under natural conditions that would be encountered for prosthetic applications, thus allowing simultaneous extraction of continuous and discrete signals without requiring multisite surgical implants. We found that limb movements can be decoded robustly and with high accuracy from a small population of neural units under free gaze in a complex 3D point-to-point reaching task. Both animals' brain-control performance improved rapidly with practice, resulting in faster target acquisition and increasing accuracy. These findings disprove the notion that the motor cortical areas are the only candidate areas for continuous prosthetic command signals and, rather, suggests that PPC can provide equally useful trajectory signals in addition to discrete, cognitive variables. Hybrid use of continuous and discrete signals from PPC may enable a new generation of neural prostheses providing superior performance and additional flexibility in addressing individual patient needs.

  3. The role of human parietal area 7A as a link between sequencing in hand actions and in overt speech production

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    Stefan eHeim

    2012-12-01

    Full Text Available Research on the evolutionary basis of the human language faculty has proposed the mirror neuron system as a link between motor processing and speech development. Consequently, most work has focussed on the left inferior frontal cortex, in particular Broca's region, and the left inferior parietal cortex. However, the direct link between planning of hand motor and speech actions remains to be elucidated. Thus, the present study investigated whether sequencing of hand motor actions vs. speech motor actions has a common neural denominator. For the hand motor task, 25 subjects performed single, repeated, or sequenced button presses with either the left or right hand. The speech task was in analogy; the same subjects produced the syllable "po" once or repeatedly, or a sequence of different syllables (po-pi-po. Speech motor vs. hand motor effectors resulted in increased perisylvian activation including Broca's region (left area 44 and areas medially adjacent to left area 45. In contrast, common activation for sequenced vs. repeated production of button presses and syllables revealed the effector-independent involvement of left area 7A in the superior parietal lobule (SPL in sequencing. These data demonstrate that sequencing of vocal gestures, an important precondition for ordered utterances and ultimately human speech, shares area 7A, rather than inferior parietal regions, as a common cortical module with hand motor sequencing. Interestingly, area 7A has previously also been shown to be involved in the observation of hand and non-hand actions. In combination with the literature, the present data thus suggest a distinction between area 44, which is specifically recruited for (cognitive aspects of speech, and SPL area 7A for general aspects of motor sequencing. In sum, the study demonstrates a yet little considered role of the superior parietal lobule in the origins of speech, and may be discussed in the light of embodiment of speech and language in the

  4. Preparative activities in posterior parietal cortex for self-paced movement in monkeys.

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    Gemba, Hisae; Matsuura-Nakao, Kazuko; Matsuzaki, Ryuichi

    2004-02-26

    Cortical field potentials were recorded by electrodes implanted chronically on the surface and at a 2.0-3.0 mm depth in various cortices in monkeys performing self-paced finger, toe, mouth, hand or trunk movements. Surface-negative, depth-positive potentials (readiness potential) appeared in the posterior parietal cortex about 1.0 s before onset of every self-paced movement, as well as in the premotor, motor and somatosensory cortices. Somatotopical distribution was seen in the readiness potential in the posterior parietal cortex, although it was not so distinct as that in the motor or somatosensory cortex. This suggests that the posterior parietal cortex is involved in preparation for self-paced movement of any body part. This study contributes to the investigation of central nervous mechanisms of voluntary movements initiated by internal stimulus.

  5. [Ictal Gerstmann's syndrome in a patient with symptomatic parietal lobe epilepsy].

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    Shimotake, Akihiro; Fujita, Youshi; Ikeda, Akio; Tomimoto, Hidekazu; Takahashi, Jun; Takahashi, Ryosuke

    2008-03-01

    A 34-year-old man with astrocytoma in the left parietal lobe had symptomatic partial epilepsy, and he presented transient episodes of acalculia, agraphia and finger agnosia. Occasionally he had difficulty in finding appropriate letters when making an e-mail, and difficulty in writing and calculation. Neurological examinations revealed ictal symptoms of Gerstmann's syndrome without right to left disorientation. No other higher cortical dysfunction or neurological deficits were noted. Scalp EEGs showed frequent, regional ictal discharges in the left parietal area lasting for 60-240 seconds. These clinico-electrographical observations strongly support that epileptic seizures produced a loss of cortical higher function manifesting Gerstmann's syndrome.

  6. Contributions to singing ability by the posterior portion of the superior temporal gyrus of the non-language-dominant hemisphere: first evidence from subdural cortical stimulation, Wada testing, and fMRI.

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    Suarez, Ralph O; Golby, Alexandra; Whalen, Stephen; Sato, Susumu; Theodore, William H; Kufta, Conrad V; Devinsky, Orrin; Balish, Marshall; Bromfield, Edward B

    2010-03-01

    Although the substrates that mediate singing abilities in the human brain are not well understood, invasive brain mapping techniques used for clinical decision making such as intracranial electro-cortical testing and Wada testing offer a rare opportunity to examine music-related function in a select group of subjects, affording exceptional spatial and temporal specificity. We studied eight patients with medically refractory epilepsy undergoing indwelling subdural electrode seizure focus localization. All patients underwent Wada testing for language lateralization. Functional assessment of language and music tasks was done by electrode grid cortical stimulation. One patient was also tested non-invasively with functional magnetic resonance imaging (fMRI). Functional organization of singing ability compared to language ability was determined based on four regions-of-interest (ROIs): left and right inferior frontal gyrus (IFG), and left and right posterior superior temporal gyrus (pSTG). In some subjects, electrical stimulation of dominant pSTG can interfere with speech and not singing, whereas stimulation of non-dominant pSTG area can interfere with singing and not speech. Stimulation of the dominant IFG tends to interfere with both musical and language expression, while non-dominant IFG stimulation was often observed to cause no interference with either task; and finally, that stimulation of areas adjacent to but not within non-dominant pSTG typically does not affect either ability. Functional fMRI mappings of one subject revealed similar music/language dissociation with respect to activation asymmetry within the ROIs. Despite inherent limitations with respect to strictly research objectives, invasive clinical techniques offer a rare opportunity to probe musical and language cognitive processes of the brain in a select group of patients. Copyright (c) 2009 Elsevier Srl. All rights reserved.

  7. A proposed number system for the 107 cortical areas of Economo and Koskinas, and Brodmann area correlations.

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    Triarhou, Lazaros C

    2007-01-01

    In their Atlas of Cytoarchitectonics of the Adult Human Cerebral Cortex, Economo and Koskinas defined 54 'ground,' 76 'variant,' and 107 'modification' areas. The 107 modifications are topographically distributed as 35 frontal, 13 superior limbic, 6 insular, 18 parietal, 7 occipital, 14 temporal and 14 inferior limbic (or hippocampal). One way to make the Economo-Koskinas system more practical is to encode the complex symbol notations of the 107 cortical areas with numbers EK 1 through EK 107. The present study does that, and it further correlates Economo-Koskinas areas with Brodmann areas, based on an overview of the classical and modern neurohistological literature. Copyright (c) 2007 S. Karger AG, Basel.

  8. Parietal network underlying movement control: disturbances during subcortical electrostimulation.

    Science.gov (United States)

    Almairac, Fabien; Herbet, Guillaume; Moritz-Gasser, Sylvie; Duffau, Hugues

    2014-07-01

    Our understanding of brain movement control has changed over the last two decades. Recent findings in the monkey and in humans have led to a parallel and interconnected network. Nevertheless, little is known about these networks. Here, we present two cases of patients with a parietal low-grade glioma. They underwent surgery under local anesthesia with cortical and subcortical mapping. For patient 1, subcortical electrostimulation immediately posterior to thalamocortical fibers induced movement disorders, with an inhibition of leg and arm movements medially and, more laterally, an acceleration of arm movement. For patient 2, electrostimulation of white matter immediately posterior to thalamocortical fibers induced an inhibition of both arm movement. It means that the detected fibers in the parietal lobe may be involved in the motor control modulation. They are distributed veil-like immediately posterior to thalamocortical pathways and could correspond to a fronto-parietal movement control subnetwork. These two cases highlight the major role of the subcortical connectivity in movement regulation, involving parietal lobe, thus the necessity to be identified and preserved during brain surgery.

  9. Choline acetyltransferase-containing neurons in the human parietal neocortex

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    V Benagiano

    2009-06-01

    Full Text Available A number of immunocytochemical studies have indicated the presence of cholinergic neurons in the cerebral cortex of various species of mammals. Whether such cholinergic neurons in the human cerebral cortex are exclusively of subcortical origin is still debated. In this immunocytochemical study, the existence of cortical cholinergic neurons was investigated on surgical samples of human parietal association neocortex using a highly specific monoclonal antibody against choline acetyltransferase (ChAT, the acetylcholine biosynthesising enzyme. ChAT immunoreactivity was detected in a subpopulation of neurons located in layers II and III. These were small or medium-sized pyramidal neurons which showed cytoplasmic immunoreactivity in the perikarya and processes, often in close association to blood microvessels. This study, providing demonstration of ChAT neurons in the human parietal neocortex, strongly supports the existence of intrinsic cholinergic innervation of the human neocortex. It is likely that these neurons contribute to the cholinergic innervation of the intracortical microvessels.

  10. The characteristics of cortical glucose metabolism in amblyopia

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    Ahn, Ji Young [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of); Lee, Dong Soo; Chung, June Key; Shin, Seung Ai; Lee, Myung Chul [College of Medicine, Ewha Womans Univ., Seoul (Korea, Republic of)

    2000-07-01

    Cortical metabolism of amblyopia patients was investigated with F-18-FDG PET and Statistical Parametric Mapping (SPM) and quantificiation based on volume of interest (VOI) by statistical probabilistic anatomical map (SPAM). In 9 amblyopic patients (12{+-}7 years ) and 20 normal subjects (23{+-}2 years), F-18-FDG PET scans were peformed in amblyopic patients after amblyopic eye or sound eye was patch-closed during PET studies. SPM was done with SPM96. By multiplying SPAM to FDG images, counts of 98 VOI's were calculated and compared with 3 S. D. range of those of normal subjects. On SPM, cortical metabolism decreased (p<0.05) in occipital lobe (Ba 17, 18, 19), superior partietal lobe (Ba 7), and inferior temporal lobe (BA 37, 20). FDG uptake of gyri of occuipital lobe was decreased in 2 and increased in 2, and was normal in the other 5. FDG uptake of gyri of parietal, frontal, and temporal lobes were decreased in FDG uptake on these VOIs. We conclude that cortical metabolism in occipital lobe and extraoccipital lobes was variable but was consistent regardless of visual input during PET studies in amblyopic patients. SPM and quantification of functional images using SPAM could reveal subtle differences or changes according to visual input. The significance of metabolic changes of extraoccipital lobes should be studies further.

  11. Estimating frontal and parietal involvement in cognitive estimation: a study of focal neurodegenerative diseases

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    Teagan Ann Bisbing

    2015-06-01

    Full Text Available We often estimate an unknown value based on available relevant information, a process known as cognitive estimation. In this study, we assess the cognitive and neuroanatomic basis for quantitative estimation by examining deficits in patients with focal neurodegenerative disease in frontal and parietal cortex. Executive function and number knowledge are key components in cognitive estimation. Prefrontal cortex has been implicated in multilevel reasoning and planning processes, and parietal cortex has been associated with number knowledge required for such estimations. We administered the Biber Cognitive Estimation Test (BCET to assess cognitive estimation in 22 patients with prefrontal disease due to behavioral variant frontotemporal dementia (bvFTD, to 17 patients with parietal disease due to corticobasal syndrome (CBS or posterior cortical atrophy (PCA and 11 patients with mild cognitive impairment (MCI. Both bvFTD and CBS/PCA patients had significantly more difficulty with cognitive estimation than controls. MCI were not impaired on BCET relative to controls. Regression analyses related BCET performance to gray matter atrophy in right lateral prefrontal and orbital frontal cortices in bvFTD, and to atrophy in right inferior parietal cortex, right insula and fusiform cortices in CBS/PCA. These results are consistent with the hypothesis that a frontal-parietal network plays a crucial role in cognitive estimation.

  12. Estimating frontal and parietal involvement in cognitive estimation: a study of focal neurodegenerative diseases

    Science.gov (United States)

    Bisbing, Teagan A.; Olm, Christopher A.; McMillan, Corey T.; Rascovsky, Katya; Baehr, Laura; Ternes, Kylie; Irwin, David J.; Clark, Robin; Grossman, Murray

    2015-01-01

    We often estimate an unknown value based on available relevant information, a process known as cognitive estimation. In this study, we assess the cognitive and neuroanatomic basis for quantitative estimation by examining deficits in patients with focal neurodegenerative disease in frontal and parietal cortex. Executive function and number knowledge are key components in cognitive estimation. Prefrontal cortex has been implicated in multilevel reasoning and planning processes, and parietal cortex has been associated with number knowledge required for such estimations. We administered the Biber cognitive estimation test (BCET) to assess cognitive estimation in 22 patients with prefrontal disease due to behavioral variant frontotemporal dementia (bvFTD), to 17 patients with parietal disease due to corticobasal syndrome (CBS) or posterior cortical atrophy (PCA) and 11 patients with mild cognitive impairment (MCI). Both bvFTD and CBS/PCA patients had significantly more difficulty with cognitive estimation than controls. MCI were not impaired on BCET relative to controls. Regression analyses related BCET performance to gray matter atrophy in right lateral prefrontal and orbital frontal cortices in bvFTD, and to atrophy in right inferior parietal cortex, right insula, and fusiform cortices in CBS/PCA. These results are consistent with the hypothesis that a frontal-parietal network plays a crucial role in cognitive estimation. PMID:26089786

  13. Characterization of Cortical Networks and Corticocortical Functional Connectivity Mediating Arbitrary Visuomotor Mapping.

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    Brovelli, Andrea; Chicharro, Daniel; Badier, Jean-Michel; Wang, Huifang; Jirsa, Viktor

    2015-09-16

    Adaptive behaviors are built on the arbitrary linkage of sensory inputs to actions and goals. Although the sensorimotor and associative frontostriatal circuits are known to mediate arbitrary visuomotor mappings, the underlying corticocortico dynamics remain elusive. Here, we take a novel approach exploiting gamma-band neural activity to study the human cortical networks and corticocortical functional connectivity mediating arbitrary visuomotor mapping. Single-trial gamma-power time courses were estimated for all Brodmann areas by combing magnetoencephalographic and MRI data with spectral analysis and beam-forming techniques. Linear correlation and Granger causality analyses were performed to investigate functional connectivity between cortical regions. The performance of visuomotor associations was characterized by an increase in gamma-power and functional connectivity over the sensorimotor and frontoparietal network, in addition to medial prefrontal areas. The superior parietal area played a driving role in the network, exerting Granger causality on the dorsal premotor area. Premotor areas acted as relay from parietal to medial prefrontal cortices, which played a receiving role in the network. Link community analysis further revealed that visuomotor mappings reflect the coordination of multiple subnetworks with strong overlap over motor and frontoparietal areas. We put forward an associative account of the underlying cognitive processes and corticocortical functional connectivity. Overall, our approach and results provide novel perspectives toward a better understanding of how distributed brain activity coordinates adaptive behaviors. In everyday life, most of our behaviors are based on the arbitrary linkage of sensory information to actions and goals, such as stopping at a red traffic light. Despite their automaticity, such behaviors rely on the activity of a large brain network and elusive interareal functional connectivity. We take a novel approach exploiting

  14. Cortical atrophy in presymptomatic Alzheimer's disease presenilin 1 mutation carriers.

    Science.gov (United States)

    Quiroz, Yakeel T; Stern, Chantal E; Reiman, Eric M; Brickhouse, Michael; Ruiz, Adriana; Sperling, Reisa A; Lopera, Francisco; Dickerson, Bradford C

    2013-05-01

    Sporadic late-onset Alzheimer's disease (AD) dementia has been associated with a 'signature' of cortical atrophy in paralimbic and heteromodal association regions measured with MRI. To investigate whether a similar pattern of cortical atrophy is present in presymptomatic presenilin 1 E280A mutation carriers an average of 6 years before clinical symptom onset. 40 cognitively normal volunteers from a Colombian population with familial AD were included; 18 were positive for the AD-associated presenilin 1 mutation (carriers, mean age=38) whereas 22 were non-carriers. T1-weighted volumetric MRI images were acquired and cortical thickness was measured. A priori regions of interest from our previous work were used to obtain thickness from AD-signature regions. Compared to non-carriers, presymptomatic presenilin 1 mutation carriers exhibited thinner cortex within the AD-signature summary measure (p<0.008). Analyses of individual regions demonstrated thinner angular gyrus, precuneus and superior parietal lobule in carriers compared to non-carriers, with trend-level effects in the medial temporal lobe. Results demonstrate that cognitively normal individuals genetically determined to develop AD have a thinner cerebral cortex than non-carriers in regions known to be affected by typical late-onset sporadic AD. These findings provide further support for the hypothesis that cortical atrophy is present in preclinical AD more than 5 years prior to symptom onset. Further research is needed to determine whether this method could be used to characterise the age-dependent trajectory of cortical atrophy in presymptomatic stages of AD.

  15. Parietal transcranial direct current stimulation modulates primary motor cortex excitability.

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    Rivera-Urbina, Guadalupe Nathzidy; Batsikadze, Giorgi; Molero-Chamizo, Andrés; Paulus, Walter; Kuo, Min-Fang; Nitsche, Michael A

    2015-03-01

    The posterior parietal cortex is part of the cortical network involved in motor learning and is structurally and functionally connected with the primary motor cortex (M1). Neuroplastic alterations of neuronal connectivity might be an important basis for learning processes. These have however not been explored for parieto-motor connections in humans by transcranial direct current stimulation (tDCS). Exploring tDCS effects on parieto-motor cortical connectivity might be functionally relevant, because tDCS has been shown to improve motor learning. We aimed to explore plastic alterations of parieto-motor cortical connections by tDCS in healthy humans. We measured neuroplastic changes of corticospinal excitability via motor evoked potentials (MEP) elicited by single-pulse transcranial magnetic stimulation (TMS) before and after tDCS over the left posterior parietal cortex (P3), and 3 cm posterior or lateral to P3, to explore the spatial specificity of the effects. Furthermore, short-interval intracortical inhibition/intracortical facilitation (SICI/ICF) over M1, and parieto-motor cortical connectivity were obtained before and after P3 tDCS. The results show polarity-dependent M1 excitability alterations primarily after P3 tDCS. Single-pulse TMS-elicited MEPs, M1 SICI/ICF at 5 and 7 ms and 10 and 15 ms interstimulus intervals (ISIs), and parieto-motor connectivity at 10 and 15 ms ISIs were all enhanced by anodal stimulation. Single pulse-TMS-elicited MEPs, and parieto-motor connectivity at 10 and 15 ms ISIs were reduced by cathodal tDCS. The respective corticospinal excitability alterations lasted for at least 120 min after stimulation. These results show an effect of remote stimulation of parietal areas on M1 excitability. The spatial specificity of the effects and the impact on parietal cortex-motor cortex connections suggest a relevant connectivity-driven effect.

  16. Neural networks underlying parietal lobe seizures: a quantified study from intracerebral recordings.

    Science.gov (United States)

    Bartolomei, Fabrice; Gavaret, Martine; Hewett, Russell; Valton, Luc; Aubert, Sandrine; Régis, Jean; Wendling, Fabrice; Chauvel, Patrick

    2011-02-01

    In this study we have quantified the "epileptogenicity" of several brain regions in seizures originating in the posterior parietal cortex in 17 patients investigated by intracerebral recordings using stereotactic EEG (SEEG). Epileptogenicity of brain structures was quantified according to the "epileptogenicity index" (EI), a way to quantify rapid discharges at seizure onset. Seven patients had maximal epileptogenicity in the superior parietal lobule-BA area 7 (Gr1), 2 patients in the superior parietal lobule-area 5 (Gr2), 4 patients in inferior parietal lobule (Gr3) and 4 in the opercular region (Gr4). A large majority of patients (15/17 (88%)) reported to have at least one aura during the course of their disease. Somato-sensory manifestations were reported in the four groups. Vestibular disturbance was observed mainly in seizures from the superior parietal lobule (Gr1 and 2). Ipsilateral version was the most frequent objective manifestation (64%). Hyperkinetic behaviour (motor agitation) was found to be frequent, observed in 4/17 cases (23%) and observed in seizures from inferior parietal regions. In conclusion, the electrophysiological organization and the clinical manifestations of PLS are various and complex. The subjective manifestations are frequent and often suggestive, therefore must be actively sought. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Subcortical mapping of calculation processing in the right parietal lobe.

    Science.gov (United States)

    Della Puppa, Alessandro; De Pellegrin, Serena; Lazzarini, Anna; Gioffrè, Giorgio; Rustemi, Oriela; Cagnin, Annachiara; Scienza, Renato; Semenza, Carlo

    2015-05-01

    Preservation of calculation processing in brain surgery is crucial for patients' quality of life. Over the last decade, surgical electrostimulation was used to identify and preserve the cortical areas involved in such processing. Conversely, subcortical connectivity among different areas implicated in this function remains unclear, and the role of surgery in this domain has not been explored so far. The authors present the first 2 cases in which the subcortical functional sites involved in calculation were identified during right parietal lobe surgery. Two patients affected by a glioma located in the right parietal lobe underwent surgery with the aid of MRI neuronavigation. No calculation deficits were detected during preoperative assessment. Cortical and subcortical mapping were performed using a bipolar stimulator. The current intensity was determined by progressively increasing the amplitude by 0.5-mA increments (from a baseline of 1 mA) until a sensorimotor response was elicited. Then, addition and multiplication calculation tasks were administered. Corticectomy was performed according to both the MRI neuronavigation data and the functional findings obtained through cortical mapping. Direct subcortical electrostimulation was repeatedly performed during tumor resection. Subcortical functional sites for multiplication and addition were detected in both patients. Electrostimulation interfered with calculation processing during cortical mapping as well. Functional sites were spared during tumor removal. The postoperative course was uneventful, and calculation processing was preserved. Postoperative MRI showed complete resection of the tumor. The present preliminary study shows for the first time how functional mapping can be a promising method to intraoperatively identify the subcortical functional sites involved in calculation processing. This report therefore supports direct electrical stimulation as a promising tool to improve the current knowledge on

  18. Cortical fMRI activation produced by attentive tracking of moving targets.

    Science.gov (United States)

    Culham, J C; Brandt, S A; Cavanagh, P; Kanwisher, N G; Dale, A M; Tootell, R B

    1998-11-01

    Attention can be used to keep track of moving items, particularly when there are multiple targets of interest that cannot all be followed with eye movements. Functional magnetic resonance imaging (fMRI) was used to investigate cortical regions involved in attentive tracking. Cortical flattening techniques facilitated within-subject comparisons of activation produced by attentive tracking, visual motion, discrete attention shifts, and eye movements. In the main task, subjects viewed a display of nine green "bouncing balls" and used attention to mentally track a subset of them while fixating. At the start of each attentive-tracking condition, several target balls (e.g., 3/9) turned red for 2 s and then reverted to green. Subjects then used attention to keep track of the previously indicated targets, which were otherwise indistinguishable from the nontargets. Attentive-tracking conditions alternated with passive viewing of the same display when no targets had been indicated. Subjects were pretested with an eye-movement monitor to ensure they could perform the task accurately while fixating. For seven subjects, functional activation was superimposed on each individual's cortically unfolded surface. Comparisons between attentive tracking and passive viewing revealed bilateral activation in parietal cortex (intraparietal sulcus, postcentral sulcus, superior parietal lobule, and precuneus), frontal cortex (frontal eye fields and precentral sulcus), and the MT complex (including motion-selective areas MT and MST). Attentional enhancement was absent in early visual areas and weak in the MT complex. However, in parietal and frontal areas, the signal change produced by the moving stimuli was more than doubled when items were tracked attentively. Comparisons between attentive tracking and attention shifting revealed essentially identical activation patterns that differed only in the magnitude of activation. This suggests that parietal cortex is involved not only in discrete

  19. Spatial imagery relies on a sensory independent, though sensory sensitive, functional organization within the parietal cortex: a fMRI study of angle discrimination in sighted and congenitally blind individuals.

    Science.gov (United States)

    Bonino, Daniela; Ricciardi, Emiliano; Bernardi, Giulio; Sani, Lorenzo; Gentili, Claudio; Vecchi, Tomaso; Pietrini, Pietro

    2015-02-01

    Although vision offers distinctive information to space representation, individuals who lack vision since birth often show perceptual and representational skills comparable to those found in sighted individuals. However, congenitally blind individuals may result in impaired spatial analysis, when engaging in 'visual' spatial features (e.g., perspective or angle representation) or complex spatial mental abilities. In the present study, we measured behavioral and brain responses using functional magnetic resonance imaging in sighted and congenitally blind individuals during spatial imagery based on a modified version of the mental clock task (e.g., angle discrimination) and a simple recognition control condition, as conveyed across distinct sensory modalities: visual (sighted individuals only), tactile and auditory. Blind individuals were significantly less accurate during the auditory task, but comparable-to-sighted during the tactile task. As expected, both groups showed common neural activations in intraparietal and superior parietal regions across visual and non-visual spatial perception and imagery conditions, indicating the more abstract, sensory independent functional organization of these cortical areas, a property that we named supramodality. At the same time, however, comparisons in brain responses and functional connectivity patterns across experimental conditions demonstrated also a functional lateralization, in a way that correlated with the distinct behavioral performance in blind and sighted individuals. Specifically, blind individuals relied more on right parietal regions, mainly in the tactile and less in the auditory spatial processing. In sighted, spatial representation across modalities relied more on left parietal regions. In conclusions, intraparietal and superior parietal regions subserve supramodal spatial representations in sighted and congenitally blind individuals. Differences in their recruitment across non-visual spatial processing in

  20. A Preliminary Study of the Influence of Age of Onset and Childhood Trauma on Cortical Thickness in Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Natalia Jaworska

    2014-01-01

    Full Text Available Background. Major depressive disorder (MDD neural underpinnings may differ based on onset age and childhood trauma. We assessed cortical thickness in patients who differed in age of MDD onset and examined trauma history influence. Methods. Adults with MDD (N=36 and controls (HC; N=18 underwent magnetic resonance imaging. Twenty patients had MDD onset 25 years of age (adult onset. The MDD group was also subdivided into those with (N=12 and without (N=19 physical and/or sexual abuse as assessed by the Childhood Trauma Questionnaire (CTQ. Cortical thickness was analyzed with FreeSurfer software. Results. Thicker frontal pole and a tendency for thinner transverse temporal cortices existed in MDD. The former was driven by the pediatric onset group and abuse history (independently, particularly in the right frontal pole. Inverse correlations existed between CTQ scores and frontal pole cortex thickness. A similar inverse relation existed with left inferior and right superior parietal cortex thickness. The superior temporal cortex tended to be thinner in pediatric versus adult onset groups with childhood abuse. Conclusions. This preliminary work suggests neural differences between pediatric and adult MDD onset. Trauma history also contributes to cytoarchitectural modulation. Thickened frontal pole cortices as a compensatory mechanism in MDD warrant evaluation.

  1. Prearcuate cortex in the Cebus monkey has cortical and subcortical connections like the macaque frontal eye field and projects to fastigial-recipient oculomotor-related brainstem nuclei.

    Science.gov (United States)

    Leichnetz, G R; Gonzalo-Ruiz, A

    1996-01-01

    The cortical and subcortical connections of the prearcuate cortex were studied in capuchin monkeys (Cebus apella, albifrons) using the anterograde and retrograde transport capabilities of the horseradish peroxidase technique. The findings demonstrate remarkable similarities to those of the macaque frontal eye field and strongly support their homology. The report then focuses on specific prearcuate projections to oculomotor-related brainstem nuclei that were shown in a companion experiment to entertain connections with the caudal oculomotor portion of the cerebellar fastigial nucleus. The principal corticocortical connections of the cebus prearcuate cortex were with dorsomedial prefrontal cortex, lateral intraparietal sulcal cortex, posterior medial parietal cortex, and superior temporal sulcal cortex, which were for the most part reciprocal and columnar in organization. The connections of the dorsal prearcuate region were heavier to the dorsomedial prefrontal and posterior medial parietal cortices, and those of the ventral region were heavier to the superior temporal sulcal cortex. The prearcuate cortex projects to several brainstem areas which also receive projections from the caudal fastigial nucleus, including the supraoculomotor periaqueductal gray matter, superior colliculus, medial nucleus reticularis tegmenti pontis, dorsomedial basilar pontine nucleus, dorsolateral basilar pontine nucleus, nucleus reticularis pontis caudalis, pontine raphe, and nucleus prepositus hypoglossi. The findings define a neuroanatomical framework within which convergence of prearcuate (putative frontal eye field) and caudal fastigial nucleus connections might occur, facilitating their potential interaction in saccadic and smooth pursuit eye movement.

  2. Reconsidering harbingers of dementia: progression of parietal lobe white matter hyperintensities predicts Alzheimer's disease incidence.

    Science.gov (United States)

    Brickman, Adam M; Zahodne, Laura B; Guzman, Vanessa A; Narkhede, Atul; Meier, Irene B; Griffith, Erica Y; Provenzano, Frank A; Schupf, Nicole; Manly, Jennifer J; Stern, Yaakov; Luchsinger, José A; Mayeux, Richard

    2015-01-01

    Accumulating evidence implicates small vessel cerebrovascular disease, visualized as white matter hyperintensities (WMH) on T2-weighted magnetic resonance imaging, in the pathogenesis and diagnosis of Alzheimer's disease (AD). Cross-sectional volumetric measures of WMH, particularly in the parietal lobes, are associated with increased risk of AD. In the present study, we sought to determine whether the longitudinal regional progression of WMH predicts incident AD above-and-beyond traditional radiological markers of neurodegeneration (i.e., hippocampal atrophy and cortical thickness). Three hundred three nondemented older adults (mean age = 79.24 ± 5.29) received high-resolution magnetic resonance imaging at baseline and then again 4.6 years (standard deviation = 1.01) later. Over the follow-up interval 26 participants progressed to AD. Using structural equation modeling, we calculated latent difference scores of parietal and nonparietal WMH, hippocampus volumes, and cortical thickness values in AD-related regions. Within the structural equation modeling framework, we determined whether baseline or change scores or both predicted AD conversion, while controlling for several time-invariant relevant variables. Smaller baseline hippocampus volume, change in hippocampus volume (i.e., atrophy), higher baseline parietal lobe WMH, and increasing parietal lobe WMH volume but not WMH in other regions or measures of cortical thickness, independently predicted progression to AD. The findings provide strong evidence that regionally accumulating WMH predict AD onset in addition to hallmark neurodegenerative changes typically associated with AD. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Reduced cortical and subcortical volumes in female adolescents with borderline personality disorder.

    Science.gov (United States)

    Richter, Julia; Brunner, Romuald; Parzer, Peter; Resch, Franz; Stieltjes, Bram; Henze, Romy

    2014-03-30

    Volumetric alterations in limbic structures have been detected in adults, but not in adolescents with borderline personality disorder (BPD). We examined adolescents in the early stages of BPD to provide a unique opportunity to investigate which parts of the brain are initially affected by the disorder before confounding factors such as long-term medication or chronicity can mask them. A group of 60 right-handed female adolescents between 14 and 18 years of age (20 patients with BPD, 20 clinical controls, and 20 healthy controls) underwent magnetic resonance imaging (MRI). Focus was on the examination of hippocampal and amygdalar volume differences. Furthermore, a cortical thickness analysis was conducted. FreeSurfer software detected significant group differences in the right and left hippocampus and in the right amygdala. Additionally, significant volume reductions in frontal (right middle frontal gyrus, orbital part of the inferior frontal gyrus bilaterally), and parietal regions (superior parietal gyrus bilaterally) were found in adolescents with BPD compared with controls. No group differences in cortical thickness were revealed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Longitudinal trajectories of cortical thickness as a biomarker for psychosis in individuals with 22q11.2 deletion syndrome.

    Science.gov (United States)

    Ramanathan, Seetha; Mattiaccio, Leah M; Coman, Ioana L; Botti, Jo-Anna C; Fremont, Wanda; Faraone, Stephen V; Antshel, Kevin M; Kates, Wendy R

    2016-12-14

    22q11.2 deletion syndrome (DS) or velo-cardio-facial syndrome (VCFS) is a genetic condition that has been identified as the highest genetic risk factor for developing psychotic illnesses. This unique biological nature of 22q11DS provides a valuable opportunity to explore predictive biomarkers of psychosis. In this study, we examined the relationship of cortical thickness and surface area between various brain regions and prodromal symptoms of psychosis. 75 probands with 22q11DS, 32 age-matched controls and 28 siblings underwent MRIs over 2 or 3 timepoints. Longitudinal mixed model regression analyses, with age as an interaction variable, were carried out to study the differences in longitudinal trajectories of change in average cortical thickness and surface area over 6-9years. Similar analyses were carried out to examine the relationship with positive prodromal symptoms of psychosis. Significant differences were noted in the inferior and superior parietal regions in both the average thickness and longitudinal change in cortical thickness with age between the probands and controls. Significant associations were also noted between regions in the frontal cortex and positive prodromal symptoms among probands. No associations were noted with cortical surface area. Our results indicate that individuals with 22q11DS who develop positive prodromal symptoms demonstrate differential longitudinal trajectories of cortical thickness in some regions of the frontal lobe. Our results suggest that the pruning stage associated with adolescent brain development may be disrupted. Copyright © 2016. Published by Elsevier B.V.

  5. The Superior Transvelar Approach to the Fourth Ventricle and Brainstem

    OpenAIRE

    Ezer, Haim; Banerjee, Anirban Deep; Bollam, Papireddy; Guthikonda, Bharat; Nanda, Anil

    2012-01-01

    Objective The superior transvelar approach is used to access pathologies located in the fourth ventricle and brainstem. The surgical path is below the venous structures, through the superior medullary velum. Following splitting the tentorial edge, near the tentorial apex, the superior medullary velum is split in the cerebello-mesencephalic fissure. Using the supracerebellar infratentorial, transtentorial or parietal interhemispheric routes, the superior medullary velum is approached. Splittin...

  6. 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

  7. Brain morphology and neuropsychological profiles in a family displaying dyslexia and superior nonverbal intelligence.

    Science.gov (United States)

    Craggs, Jason G; Sanchez, Juliana; Kibby, Michelle Y; Gilger, Jeffrey W; Hynd, George W

    2006-11-01

    Behavioral research suggests that individuals with dyslexia may have exceptional skills in nonverbal cognitive processes, while genetic studies have noted that giftedness, high IQ and/or special talents tend to run in families. Taken together, these results suggest that persons within families (particularly offspring) may share similar cortical systems supporting those functions. Postmortem and in vivo imaging studies have linked dyslexia to abnormalities in the structures associated with the parietal operculum (PO) (e.g., planum temporale, supramarginal gyrus, and angular gyrus). In this paper we present data on a single family showing a link between dyslexia, superior nonverbal IQ and atypical PO presentation. We consider the psychometric and neurological patterns of this family as a tentative etiological test of the putative dyslexia-talent association.

  8. [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.

  9. Mapping the cortical representation of speech sounds in a syllable repetition task.

    Science.gov (United States)

    Markiewicz, Christopher J; Bohland, Jason W

    2016-11-01

    Speech repetition relies on a series of distributed cortical representations and functional pathways. A speaker must map auditory representations of incoming sounds onto learned speech items, maintain an accurate representation of those items in short-term memory, interface that representation with the motor output system, and fluently articulate the target sequence. A "dorsal stream" consisting of posterior temporal, inferior parietal and premotor regions is thought to mediate auditory-motor representations and transformations, but the nature and activation of these representations for different portions of speech repetition tasks remains unclear. Here we mapped the correlates of phonetic and/or phonological information related to the specific phonemes and syllables that were heard, remembered, and produced using a series of cortical searchlight multi-voxel pattern analyses trained on estimates of BOLD responses from individual trials. Based on responses linked to input events (auditory syllable presentation), predictive vowel-level information was found in the left inferior frontal sulcus, while syllable prediction revealed significant clusters in the left ventral premotor cortex and central sulcus and the left mid superior temporal sulcus. Responses linked to output events (the GO signal cueing overt production) revealed strong clusters of vowel-related information bilaterally in the mid to posterior superior temporal sulcus. For the prediction of onset and coda consonants, input-linked responses yielded distributed clusters in the superior temporal cortices, which were further informative for classifiers trained on output-linked responses. Output-linked responses in the Rolandic cortex made strong predictions for the syllables and consonants produced, but their predictive power was reduced for vowels. The results of this study provide a systematic survey of how cortical response patterns covary with the identity of speech sounds, which will help to constrain

  10. Visuo-spatial construction in patients with frontal and parietal lobe lesions

    Directory of Open Access Journals (Sweden)

    Himani Kashyap

    2011-04-01

    Full Text Available Visuospatial construction, traditionally viewed as a putative parietal function, also requires sustained attention, planning, organization strategies and error correction, and hence frontal lobe mediation. The relative contributions of the frontal and parietal lobes are poorly understood. To examine the contributions of parietal, frontal lobes, as well as right and left cerebral hemispheres to visuospatial construction. The Stick Construction Test for two-dimensional construction and the Block Construction Test for three-dimensional construction were administered pre-surgically to patients with lesions in the parietal lobe (n =9 and the frontal lobe (n=11, along with normal control subjects (n =20 matched to the patients on age (+/- 3 years, gender, education (+/- 3 years and handedness. The patients were significantly slower than the controls on both two-dimensional and three-dimensional tests. Patients with parietal lesions were slower than those with frontal lesions on the test of three-dimensional construction. Within each lobe patients with right and left sided lesions did not differ significantly. It appears that tests of three-dimensional construction might be most sensitive to visuospatial construction deficits. Visuospatial construction involves the mediation of both frontal and parietal lobes. The function does not appear to be lateralized. The networks arising from the parieto-occipital areas and projecting to the frontal cortices (e.g., occipito-frontal fasciculus may be the basis of the mediation of both lobes in visuospatial construction. The present findings need replication from studies with larger sample sizes.

  11. [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.

  12. 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.

  13. High Frequency rTMS over the Left Parietal Lobule Increases Non-Word Reading Accuracy

    Science.gov (United States)

    Costanzo, Floriana; Menghini, Deny; Caltagirone, Carlo; Oliveri, Massimiliano; Vicari, Stefano

    2012-01-01

    Increasing evidence in the literature supports the usefulness of Transcranial Magnetic Stimulation (TMS) in studying reading processes. Two brain regions are primarily involved in phonological decoding: the left superior temporal gyrus (STG), which is associated with the auditory representation of spoken words, and the left inferior parietal lobe…

  14. Scene-Selectivity and Retinotopy in Medial Parietal Cortex

    Science.gov (United States)

    Silson, Edward H.; Steel, Adam D.; Baker, Chris I.

    2016-01-01

    Functional imaging studies in human reliably identify a trio of scene-selective regions, one on each of the lateral [occipital place area (OPA)], ventral [parahippocampal place area (PPA)], and medial [retrosplenial complex (RSC)] cortical surfaces. Recently, we demonstrated differential retinotopic biases for the contralateral lower and upper visual fields within OPA and PPA, respectively. Here, using functional magnetic resonance imaging, we combine detailed mapping of both population receptive fields (pRF) and category-selectivity, with independently acquired resting-state functional connectivity analyses, to examine scene and retinotopic processing within medial parietal cortex. We identified a medial scene-selective region, which was contained largely within the posterior and ventral bank of the parieto-occipital sulcus (POS). While this region is typically referred to as RSC, the spatial extent of our scene-selective region typically did not extend into retrosplenial cortex, and thus we adopt the term medial place area (MPA) to refer to this visually defined scene-selective region. Intriguingly MPA co-localized with a region identified solely on the basis of retinotopic sensitivity using pRF analyses. We found that MPA demonstrates a significant contralateral visual field bias, coupled with large pRF sizes. Unlike OPA and PPA, MPA did not show a consistent bias to a single visual quadrant. MPA also co-localized with a region identified by strong differential functional connectivity with PPA and the human face-selective fusiform face area (FFA), commensurate with its functional selectivity. Functional connectivity with OPA was much weaker than with PPA, and similar to that with face-selective occipital face area (OFA), suggesting a closer link with ventral than lateral cortex. Consistent with prior research, we also observed differential functional connectivity in medial parietal cortex for anterior over posterior PPA, as well as a region on the lateral

  15. Sound to language: different cortical processing for first and second languages in elementary school children as revealed by a large-scale study using fNIRS.

    Science.gov (United States)

    Sugiura, Lisa; Ojima, Shiro; Matsuba-Kurita, Hiroko; Dan, Ippeita; Tsuzuki, Daisuke; Katura, Takusige; Hagiwara, Hiroko

    2011-10-01

    A large-scale study of 484 elementary school children (6-10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L2 words were processed like nonword auditory stimuli. The activation was bilateral in the auditory and superior/middle temporal regions. Hemispheric asymmetry was observed in the inferior frontal region (right dominant), and in the inferior parietal region with interactions: low-frequency words elicited more right-hemispheric activation (particularly in the supramarginal gyrus), while high-frequency words elicited more left-hemispheric activation (particularly in the angular gyrus). The present results reveal the strong involvement of a bilateral language network in children's brains depending more on right-hemispheric processing while acquiring unfamiliar/low-frequency words. A right-to-left shift in laterality should occur in the inferior parietal region, as lexical knowledge increases irrespective of language.

  16. Sound to Language: Different Cortical Processing for First and Second Languages in Elementary School Children as Revealed by a Large-Scale Study Using fNIRS

    Science.gov (United States)

    Ojima, Shiro; Matsuba-Kurita, Hiroko; Dan, Ippeita; Tsuzuki, Daisuke; Katura, Takusige; Hagiwara, Hiroko

    2011-01-01

    A large-scale study of 484 elementary school children (6–10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L2 words were processed like nonword auditory stimuli. The activation was bilateral in the auditory and superior/middle temporal regions. Hemispheric asymmetry was observed in the inferior frontal region (right dominant), and in the inferior parietal region with interactions: low-frequency words elicited more right-hemispheric activation (particularly in the supramarginal gyrus), while high-frequency words elicited more left-hemispheric activation (particularly in the angular gyrus). The present results reveal the strong involvement of a bilateral language network in children’s brains depending more on right-hemispheric processing while acquiring unfamiliar/low-frequency words. A right-to-left shift in laterality should occur in the inferior parietal region, as lexical knowledge increases irrespective of language. PMID:21350046

  17. Refractory Lesional Parietal Lobe Epilepsy: Clinical, Electroencephalographic and Neurodiagnostic Findings.

    Science.gov (United States)

    Kurşun, Oğuzhan; Karataş, Hülya; Dericioğlu, Neşe; Saygi, Serap

    2016-09-01

    Specialized centers, in the management and surgical treatment of medically refractory epilepsy, emphasize the importance of differentiating the varieties of localization related epilepsies. There has been considerable recent interest in temporal and frontal lobe epileptic syndromes and less attention has been paid to parietal and occipital lobe epilepsies. Here we report the clinical, electroencephalographic and neuroimaging characteristics of 46 patients with medically refractory lesional parietal lobe epilepsy who have been followed up for 1-10 years. In this study auras were reported in 78.3% of the patients and included sensory symptoms (72.2%), headache (36.1%), nausea and vomiting (36.1%), psychic symptoms (36.1%) and visual symptoms (16.6%). The most common ictal behavioral changes were paresthesia (69.6%) and focal clonic activity (39.1%). Tonic posture, various automatisms, head deviation, staring, sensation of pain and speech disturbances occurred to a lesser extent. Simple partial seizures were present in 69.6%. Complex partial seizures occurred in 43.5% and secondary generalized tonic clonic seizures were reported in 58.7% of the patients. Interictal routine EEG disclosed abnormal background activity in 1/3 of the patients. Nonlocalising epileptiform abnormalities were found in 34.8% of the patients. EEG findings were normal in 34.8% of the patients. The most common presumed etiologic factors were as follows: posttraumatic encephalomalacia, stroke, tumor, malformation of cortical development, atrophy, and arteriovenous malformation. Clinical, electrophysiological and neuroimaging features of the lesional symptomatic partial epilepsy patients may help us to localize the seizure focus in some patients with cryptogenic partial epilepsy. So that, the timing decision of the parietal lobe sampling with more invasive techniques like intracranial electrodes prior to epilepsy surgery would be easier.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. Right parietal cortex mediates recognition memory for melodies.

    Science.gov (United States)

    Schaal, Nora K; Javadi, Amir-Homayoun; Halpern, Andrea R; Pollok, Bettina; Banissy, Michael J

    2015-07-01

    Functional brain imaging studies have highlighted the significance of right-lateralized temporal, frontal and parietal brain areas for memory for melodies. The present study investigated the involvement of bilateral posterior parietal cortices (PPCs) for the recognition memory of melodies using transcranial direct current stimulation (tDCS). Participants performed a recognition task before and after tDCS. The task included an encoding phase (12 melodies), a retention period, as well as a recognition phase (24 melodies). Experiment 1 revealed that anodal tDCS over the right PPC led to a deterioration of overall memory performance compared with sham. Experiment 2 confirmed the results of Experiment 1 and further showed that anodal tDCS over the left PPC did not show a modulatory effect on memory task performance, indicating a right lateralization for musical memory. Furthermore, both experiments revealed that the decline in memory for melodies can be traced back to an interference of anodal stimulation on the recollection process (remember judgements) rather than to familiarity judgements. Taken together, this study revealed a causal involvement of the right PPC for memory for melodies and demonstrated a key role for this brain region in the recollection process of the memory task. © 2015 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  20. Theta and Alpha Oscillations during the Retention Period of Working Memory by rTMS Stimulating the Parietal Lobe.

    Science.gov (United States)

    Li, Song; Jin, Jing-Na; Wang, Xin; Qi, Hong-Zhi; Liu, Zhi-Peng; Yin, Tao

    2017-01-01

    Studies on repetitive transcranial magnetic stimulation (rTMS) have shown that stimulating the parietal lobe, which plays a role in memory storage, can enhance performance during the "retention" process of working memory (WM). However, the mechanism of rTMS effect during this phase is still unclear. In this study, we stimulated the superior parietal lobe (SPL) using 5-Hz rTMS in 26 participants and recorded electroencephalography (EEG) while they performed a delayed-recognition WM task. The analyses included the comparisons of event-related spectral perturbation (ERSP) value variations in theta (4-7 Hz) and alpha (8-14 Hz) band frequencies between conditions (rTMS vs. sham), as well as the correlations between different brain areas. Following rTMS, the ERSP values of theta-band oscillations were significantly increased in the parietal and occipital-parietal brain areas (P parietal area (P parietal and left prefrontal areas were positively correlated with the response time (RT) variations (by using rTMS, the more subject RT decreased, the more ERSP value of theta oscillation increased). The ERSP value variations of alpha-band oscillations in the left parietal and bilateral prefrontal areas were negatively correlated with RT variations (by using rTMS, the more RT of the subject decreased, the more ERSP value of alpha oscillation decreased). Inter-sites phase synchronization of theta-band EEG between the left parietal and left prefrontal areas, as well as alpha-band EEG between the left parietal and bilateral prefrontal areas were enhanced by rTMS. These results indicated that activities of both parietal and prefrontal areas were required for information storage, and these activities were related to the behavioral responses. Moreover, the connectivity between these two regions was intensified following rTMS. Thus, rTMS may affect the frontal area indirectly via the frontal parietal pathway.

  1. Abnormal Parietal Brain Function in ADHD: Replication and Extension of Previous EEG Beta Asymmetry Findings

    Directory of Open Access Journals (Sweden)

    T. Sigi eHale

    2014-07-01

    Full Text Available Background: Abundant work indicates ADHD abnormal posterior brain structure and function, including abnormal structural and functional asymmetries and reduced corpus callosum size. However, this literature has attracted considerably less research interest than fronto-striatal findings. Objective: To help address this imbalance, the current study replicates and extends our previous work showing abnormal parietal brain function in ADHD adults during the Conner’s continuous performance test (CPT. Method: Our previous study found that ADHD adults had increased rightward EEG beta (16-21 Hz asymmetry in inferior parietal brain regions during the CPT (p=.00001, and that this metric exhibited a lack of normal correlation (i.e., observed in controls with beta asymmetry at temporal-parietal regions. We re-tested these effects in a new ADHD sample, and with both new and old samples combined. We additionally examined: a EEG asymmetry in multiple frequency bands, b unilateral effects for all asymmetry findings, and c the association between EEG asymmetry and a battery of cognitive tests. Results: We replicated our original findings, again demonstrating abnormal rightward inferior parietal beta asymmetry in adults with ADHD during the CPT, and again this metric exhibited abnormal reduced correlation to temporal-parietal beta asymmetry. Novel analyses also demonstrated a broader pattern of rightward beta and theta asymmetry across inferior, superior, and temporal-parietal brain regions, and showed that rightward parietal asymmetry in ADHD was atypically associated with multiple cognitive tests. Conclusion: Abnormal increased rightward parietal EEG beta asymmetry is an important feature of ADHD. We speculate that this phenotype may occur with any form of impaired capacity for top-down task-directed control over sensory encoding functions, and that it may reflect associated increases of attentional shifting and compensatory sustained/selective attention.

  2. Dynamic social adaptation of motion-related neurons in primate parietal cortex.

    Directory of Open Access Journals (Sweden)

    Naotaka Fujii

    Full Text Available Social brain function, which allows us to adapt our behavior to social context, is poorly understood at the single-cell level due largely to technical limitations. But the questions involved are vital: How do neurons recognize and modulate their activity in response to social context? To probe the mechanisms involved, we developed a novel recording technique, called multi-dimensional recording, and applied it simultaneously in the left parietal cortices of two monkeys while they shared a common social space. When the monkeys sat near each other but did not interact, each monkey's parietal activity showed robust response preference to action by his own right arm and almost no response to action by the other's arm. But the preference was broken if social conflict emerged between the monkeys-specifically, if both were able to reach for the same food item placed on the table between them. Under these circumstances, parietal neurons started to show complex combinatorial responses to motion of self and other. Parietal cortex adapted its response properties in the social context by discarding and recruiting different neural populations. Our results suggest that parietal neurons can recognize social events in the environment linked with current social context and form part of a larger social brain network.

  3. Prostate Cancer Presenting with Parietal Bone Metastasis

    Science.gov (United States)

    Pare, Abdoul Karim; Abubakar, Babagana Mustapha; Kabore, Moussa

    2017-01-01

    Bone metastases from prostate cancer are very common. They are usually located on the axial skeleton. However, cranial bone metastases especially to the parietal bone are rare. We report a case of metastatic prostate cancer presenting with left parietal bone metastasis in a patient with no urological symptoms or signs. We should consider prostate cancer in any man above 60 years presenting unusual bone lesions.

  4. Neuronal Correlates of Individual Differences in the Big Five Personality Traits: Evidences from Cortical Morphology and Functional Homogeneity

    Directory of Open Access Journals (Sweden)

    Ting Li

    2017-07-01

    Full Text Available There have been many neuroimaging studies of human personality traits, and it have already provided glimpse into the neurobiology of complex traits. And most of previous studies adopt voxel-based morphology (VBM analysis to explore the brain-personality mechanism from two levels (vertex and regional based, the findings are mixed with great inconsistencies and the brain-personality relations are far from a full understanding. Here, we used a new method of surface-based morphology (SBM analysis, which provides better alignment of cortical landmarks to generate about the associations between cortical morphology and the personality traits across 120 healthy individuals at both vertex and regional levels. While to further reveal local functional correlates of the morphology-personality relationships, we related surface-based functional homogeneity measures to the regions identified in the regional-based SBM correlation. Vertex-wise analysis revealed that people with high agreeableness exhibited larger areas in the left superior temporal gyrus. Based on regional parcellation we found that extroversion was negatively related with the volume of the left lateral occipito-temporal gyrus and agreeableness was negatively associated with the sulcus depth of the left superior parietal lobule. Moreover, increased regional homogeneity in the left lateral occipito-temporal gyrus is related to the scores of extroversion, and increased regional homogeneity in the left superior parietal lobule is related to the scores of agreeableness. These findings provide supporting evidence of a link between personality and brain structural mysteries with a method of SBM, and further suggest that local functional homogeneity of personality traits has neurobiological relevance that is likely based on anatomical substrates.

  5. Prefrontal, posterior parietal and sensorimotor network activity underlying speed control during walking

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    Thomas C Bulea

    2015-05-01

    Full Text Available Accumulating evidence suggests cortical circuits may contribute to control of human locomotion. Here, noninvasive electroencephalography (EEG recorded from able-bodied volunteers during a novel treadmill walking paradigm was used to assess neural correlates of walking. A systematic processing method, including a recently developed subspace reconstruction algorithm, reduced movement-related EEG artifact prior to independent component analysis and dipole source localization. We quantified cortical activity while participants tracked slow and fast target speeds across two treadmill conditions: an active mode that adjusted belt speed based on user movements and a passive mode reflecting a typical treadmill. Our results reveal frequency specific, multi-focal task related changes in cortical oscillations elicited by active walking. Low γ band power, localized to the prefrontal and posterior parietal cortices, was significantly increased during double support and early swing phases, critical points in the gait cycle since the active controller adjusted speed based on pelvis position and swing foot velocity. These phasic γ band synchronizations provide evidence that prefrontal and posterior parietal networks, previously implicated in visuo-spatial and somotosensory integration, are engaged to enhance lower limb control during gait. Sustained μ and β band desynchronization within sensorimotor cortex, a neural correlate for movement, was observed during walking thereby validating our methods for isolating cortical activity. Our results also demonstrate the utility of EEG recorded during locomotion for probing the multi-regional cortical networks which underpin its execution. For example, the cortical network engagement elicited by the active treadmill suggests that it may enhance neuroplasticity for more effective motor training.

  6. Parietal versus temporal lobe components in spatial cognition: Setting the mid-point of a horizontal line.

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    Oliveri, Massimiliano; Vallar, Giuseppe

    2009-09-01

    Recent anatomo-clinical correlation studies have extended to the superior temporal gyrus, the right hemisphere lesion sites associated with the left unilateral spatial neglect, in addition to the traditional posterior-inferior-parietal localization of the responsible lesion (supramarginal gyrus, at the temporo-parietal junction). The study aimed at teasing apart, by means of repetitive transcranial magnetic stimulation (rTMS), the contribution of the inferior parietal lobule (angular gyrus versus supramarginal gyrus) and of the superior temporal gyrus of the right hemisphere, in making judgments about the mid-point of a horizontal line, a widely used task for detecting and investigating spatial neglect. rTMS trains at 25 Hz frequency were delivered over the inferior parietal lobule (angular gyrus and supramarginal gyrus), the superior temporal gyrus and the anterior parietal lobe of the right hemisphere, in 10 neurologically unimpaired participants, performing a line bisection judgment task. rTMS of the inferior parietal lobule at the level of the supramarginal gyrus brought about a rightward error in the bisection judgment, ipsilateral to the side of the rTMS, with stimulation over the other sites being ineffective. The neural correlates of computing the mid-point of a horizontal segment include the right supramarginal gyrus in the inferior parietal lobule and do not extend to the angular gyrus and the superior temporal gyrus. These rTMS data in unimpaired subjects constrain the evidence from lesion studies in brain-damaged patients, emphasizing the major role of a subset of relevant regions.

  7. Face activated neurodynamic cortical networks.

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    Susac, Ana; Ilmoniemi, Risto J; Ranken, Doug; Supek, Selma

    2011-05-01

    Previous neuroimaging studies have shown that complex visual stimuli, such as faces, activate multiple brain regions, yet little is known on the dynamics and complexity of the activated cortical networks during the entire measurable evoked response. In this study, we used simulated and face-evoked empirical MEG data from an oddball study to investigate the feasibility of accurate, efficient, and reliable spatio-temporal tracking of cortical pathways over prolonged time intervals. We applied a data-driven, semiautomated approach to spatio-temporal source localization with no prior assumptions on active cortical regions to explore non-invasively face-processing dynamics and their modulation by task. Simulations demonstrated that the use of multi-start downhill simplex and data-driven selections of time intervals submitted to the Calibrated Start Spatio-Temporal (CSST) algorithm resulted in improved accuracy of the source localization and the estimation of the onset of their activity. Locations and dynamics of the identified sources indicated a distributed cortical network involved in face processing whose complexity was task dependent. This MEG study provided the first non-invasive demonstration, agreeing with intracranial recordings, of an early onset of the activity in the fusiform face gyrus (FFG), and that frontal activation preceded parietal for responses elicited by target faces.

  8. Does shape discrimination by the mouth activate the parietal and occipital lobes? - near-infrared spectroscopy study.

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    Tomonori Kagawa

    Full Text Available A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS. Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7, extrastriate cortex (BA18, BA19, and striate cortex (BA17 activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7, extrastriate cortex (BA18, 19, and striate cortex (BA17, as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth.

  9. Does Shape Discrimination by the Mouth Activate the Parietal and Occipital Lobes? – Near-Infrared Spectroscopy Study

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    Kagawa, Tomonori; Narita, Noriyuki; Iwaki, Sunao; Kawasaki, Shingo; Kamiya, Kazunobu; Minakuchi, Shunsuke

    2014-01-01

    A cross-modal association between somatosensory tactile sensation and parietal and occipital activities during Braille reading was initially discovered in tests with blind subjects, with sighted and blindfolded healthy subjects used as controls. However, the neural background of oral stereognosis remains unclear. In the present study, we investigated whether the parietal and occipital cortices are activated during shape discrimination by the mouth using functional near-infrared spectroscopy (fNIRS). Following presentation of the test piece shape, a sham discrimination trial without the test pieces induced posterior parietal lobe (BA7), extrastriate cortex (BA18, BA19), and striate cortex (BA17) activation as compared with the rest session, while shape discrimination of the test pieces markedly activated those areas as compared with the rest session. Furthermore, shape discrimination of the test pieces specifically activated the posterior parietal cortex (precuneus/BA7), extrastriate cortex (BA18, 19), and striate cortex (BA17), as compared with sham sessions without a test piece. We concluded that oral tactile sensation is recognized through tactile/visual cross-modal substrates in the parietal and occipital cortices during shape discrimination by the mouth. PMID:25299397

  10. Anatomical substrates of the alerting, orienting and executive control components of attention: focus on the posterior parietal lobe.

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    Yin, Xuntao; Zhao, Lu; Xu, Junhai; Evans, Alan C; Fan, Lingzhong; Ge, Haitao; Tang, Yuchun; Khundrakpam, Budhachandra; Wang, Jian; Liu, Shuwei

    2012-01-01

    Both neuropsychological and functional neuroimaging studies have identified that the posterior parietal lobe (PPL) is critical for the attention function. However, the unique role of distinct parietal cortical subregions and their underlying white matter (WM) remains in question. In this study, we collected both magnetic resonance imaging and diffusion tensor imaging (DTI) data in normal participants, and evaluated their attention performance using attention network test (ANT), which could isolate three different attention components: alerting, orienting and executive control. Cortical thickness, surface area and DTI parameters were extracted from predefined PPL subregions and correlated with behavioural performance. Tract-based spatial statistics (TBSS) was used for the voxel-wise statistical analysis. Results indicated structure-behaviour relationships on multiple levels. First, a link between the cortical thickness and WM integrity of the right inferior parietal regions and orienting performance was observed. Specifically, probabilistic tractography demonstrated that the integrity of WM connectivity between the bilateral inferior parietal lobules mediated the orienting performance. Second, the scores of executive control were significantly associated with the WM diffusion metrics of the right supramarginal gyrus. Finally, TBSS analysis revealed that alerting performance was significant correlated with the fractional anisotropy of local WM connecting the right thalamus and supplementary motor area. We conclude that distinct areas and features within PPL are associated with different components of attention. These findings could yield a more complete understanding of the nature of the PPL contribution to visuospatial attention.

  11. Anatomical substrates of the alerting, orienting and executive control components of attention: focus on the posterior parietal lobe.

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    Xuntao Yin

    Full Text Available Both neuropsychological and functional neuroimaging studies have identified that the posterior parietal lobe (PPL is critical for the attention function. However, the unique role of distinct parietal cortical subregions and their underlying white matter (WM remains in question. In this study, we collected both magnetic resonance imaging and diffusion tensor imaging (DTI data in normal participants, and evaluated their attention performance using attention network test (ANT, which could isolate three different attention components: alerting, orienting and executive control. Cortical thickness, surface area and DTI parameters were extracted from predefined PPL subregions and correlated with behavioural performance. Tract-based spatial statistics (TBSS was used for the voxel-wise statistical analysis. Results indicated structure-behaviour relationships on multiple levels. First, a link between the cortical thickness and WM integrity of the right inferior parietal regions and orienting performance was observed. Specifically, probabilistic tractography demonstrated that the integrity of WM connectivity between the bilateral inferior parietal lobules mediated the orienting performance. Second, the scores of executive control were significantly associated with the WM diffusion metrics of the right supramarginal gyrus. Finally, TBSS analysis revealed that alerting performance was significant correlated with the fractional anisotropy of local WM connecting the right thalamus and supplementary motor area. We conclude that distinct areas and features within PPL are associated with different components of attention. These findings could yield a more complete understanding of the nature of the PPL contribution to visuospatial attention.

  12. Abnormal parietal encephalomalacia associated with schizophrenia

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    Pan, Fen; Wang, Jun-Yuan; Xu, Yi; Huang, Man-Li

    2017-01-01

    Abstract Rationale: It is widely believed that structural abnormalities of the brain contribute to the pathophysiology of schizophrenia. The parietal lobe is a central hub of multisensory integration, and abnormities in this region might account for the clinical features of schizophrenia. However, few cases of parietal encephalomalacia associated with schizophrenia have been described. Patient concerns and Diagnoses: In this paper, we present a case of a 25-year-old schizophrenia patient with abnormal parietal encephalomalacia. The patient had poor nutrition and frequently had upper respiratory infections during childhood and adolescence. She showed severe schizophrenic symptoms such as visual hallucinations for 2 years. After examining all her possible medical conditions, we found that the patient had a lesion consistent with the diagnosis of encephalomalacia in her right parietal lobe and slight brain atrophy. Interventions: The patient was prescribed olanzapine (10 mg per day). Outcomes: Her symptoms significantly improved after antipsychotic treatment and were still well controlled 1 year later. Lessons: This case suggested that parietal encephalomalacia, which might be caused by inflammatory and infectious conditions in early life and be aggravated by undernutrition, might be implicated in the etiology of schizophrenia. PMID:28272261

  13. The cortical and sub-cortical network of sensory evoked response in healthy subjects.

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    Muthuraman, M; Hellriegel, H; Groppa, S; Deuschl, G; Raethjen, J

    2013-01-01

    The aim of this study was to find the cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects during electrical stimulation of right median nerve at wrist. The multitaper method was used to estimate the power and coherence spectrum followed by the source analysis method dynamic imaging of coherent sources (DICS) to find the highest coherent source for the basic frequency 3 Hz and the complete cortical and sub-cortical network responsible for the sensory evoked coherence in healthy subjects. The highest coherent source for the basic frequency was in the posterior parietal cortex for all the subjects. The cortical and sub-cortical network comprised of the primary sensory motor cortex (SI), secondary sensory motor cortex (SII), frontal cortex and medial pulvinar nucleus in the thalamus. The cortical and sub-cortical network responsible for the sensory evoked coherence was found successfully with a 64-channel EEG system. The sensory evoked coherence is involved with a thalamo-cortical network in healthy subjects.

  14. Neural correlates of cognitive impairment in posterior cortical atrophy.

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    Kas, Aurélie; de Souza, Leonardo Cruz; Samri, Dalila; Bartolomeo, Paolo; Lacomblez, Lucette; Kalafat, Michel; Migliaccio, Raffaella; Thiebaut de Schotten, Michel; Cohen, Laurent; Dubois, Bruno; Habert, Marie-Odile; Sarazin, Marie

    2011-05-01

    With the prospect of disease-modifying drugs that will target the physiopathological process of Alzheimer's disease, it is now crucial to increase the understanding of the atypical focal presentations of Alzheimer's disease, such as posterior cortical atrophy. This study aimed to (i) characterize the brain perfusion profile in posterior cortical atrophy using regions of interest and a voxel-based approach; (ii) study the influence of the disease duration on the clinical and imaging profiles; and (iii) explore the correlations between brain perfusion and cognitive deficits. Thirty-nine patients with posterior cortical atrophy underwent a specific battery of neuropsychological tests, mainly targeting visuospatial functions, and a brain perfusion scintigraphy with 99mTc-ethyl cysteinate dimer. The imaging analysis included a comparison with a group of 24 patients with Alzheimer's disease, matched for age, disease duration and Mini-Mental State Examination, and 24 healthy controls. The single-photon emission computed tomography profile in patients with posterior cortical atrophy was characterized by extensive and severe hypoperfusion in the occipital, parietal, posterior temporal cortices and in a smaller cortical area corresponding to the frontal eye fields (Brodmann areas 6/8). Compared with patients with Alzheimer's disease, the group with posterior cortical atrophy showed more severe occipitoparietal hypoperfusion and higher perfusion in the frontal, anterior cingulate and mesiotemporal regions. When considering the disease duration, the functional changes began and remained centred on the posterior lobes, even in the late stage. Correlation analyses of brain perfusion and neuropsychological scores in posterior cortical atrophy highlighted the prominent role of left inferior parietal damage in acalculia, Gerstmann's syndrome, left-right indistinction and limb apraxia, whereas damage to the bilateral dorsal occipitoparietal regions appeared to be involved in B

  15. Parietal cortex mediates conscious perception of illusory gestalt.

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    Zaretskaya, Natalia; Anstis, Stuart; Bartels, Andreas

    2013-01-09

    Grouping local elements into a holistic percept, also known as spatial binding, is crucial for meaningful perception. Previous studies have shown that neurons in early visual areas V1 and V2 can signal complex grouping-related information, such as illusory contours or object-border ownerships. However, relatively little is known about higher-level processes contributing to these signals and mediating global Gestalt perception. We used a novel bistable motion illusion that induced alternating and mutually exclusive vivid conscious experiences of either dynamic illusory contours forming a global Gestalt or moving ungrouped local elements while the visual stimulation remained the same. fMRI in healthy human volunteers revealed that activity fluctuations in two sites of the parietal cortex, the superior parietal lobe and the anterior intraparietal sulcus (aIPS), correlated specifically with the perception of the grouped illusory Gestalt as opposed to perception of ungrouped local elements. We then disturbed activity at these two sites in the same participants using transcranial magnetic stimulation (TMS). TMS over aIPS led to a selective shortening of the duration of the global Gestalt percept, with no effect on that of local elements. The results suggest that aIPS activity is directly involved in the process of spatial binding during effortless viewing in the healthy brain. Conscious perception of global Gestalt is therefore associated with aIPS function, similar to attention and perceptual selection.

  16. Patterns in Cortical Connectivity for Determining Outcomes in Hand Function after Subcortical Stroke

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    Yin, Dazhi; Song, Fan; Xu, Dongrong; Peterson, Bradley S.; Sun, Limin; Men, Weiwei; Yan, Xu; Fan, Mingxia

    2012-01-01

    Background and Purpose Previous studies have noted changes in resting-state functional connectivity during motor recovery following stroke. However, these studies always uncover various patterns of motor recovery. Moreover, subgroups of stroke patients with different outcomes in hand function have rarely been studied. Materials and Methods We selected 24 patients who had a subcortical stroke in the left motor pathway and displayed only motor deficits. The patients were divided into two subgroups: completely paralyzed hands (CPH) (12 patients) and partially paralyzed hands (PPH) (12 patients). Twenty-four healthy controls (HC) were also recruited. We performed functional connectivity analysis in both the ipsilesional and contralesional primary motor cortex (M1) to explore the differences in the patterns between each pair of the three diagnostic groups. Results Compared with the HC, the PPH group displays reduced connectivity of both the ipsilesional and contralesional M1 with bilateral prefrontal gyrus and contralesional cerebellum posterior lobe. The connectivity of both the ipsilesional and contralesional M1 with contralateral primary sensorimotor cortex was reduced in the CPH group. Additionally, the connectivity of the ipsilesional M1 with contralesional postcentral gyrus, superior parietal lobule and ipsilesional inferior parietal lobule was reduced in the CPH group compared with the PPH group. Moreover, the connectivity of these regions was positively correlated with the Fugl-Meyer Assessment scores (hand+wrist) across all stroke patients. Conclusions Patterns in cortical connectivity may serve as a potential biomarker for the neural substratum associated with outcomes in hand function after subcortical stroke. PMID:23285171

  17. Visual imagery influences brain responses to visual stimulation in bilateral cortical blindness.

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    de Gelder, Beatrice; Tamietto, Marco; Pegna, Alan J; Van den Stock, Jan

    2015-11-01

    Mental imagery is a powerful mechanism that may facilitate visual perception as well as compensate for it. The role of V1 in mental imagery is still a matter of debate. Our goal here was to investigate whether visual imagery was still possible in case of bilateral V1 destruction behaviorally evidenced by total clinical blindness and if so, whether it might boost residual visual perception. In a factorial fMRI design, faces, scenes or scrambled images were presented while a rare patient with cortical blindness over the whole visual field due to bilateral V1-lesions (TN) was instructed to imagine either an angry person or a neutral object (tree). The results show that visual imagery of a person activates frontal, parietal and occipital brain regions similar to control subjects and hence suggest that V1 is not necessary for visual imagery. In addition, the combination of visual stimulation and visual imagery of socio-emotional stimuli triggers activation in superior parietal lobule (SPL) and ventromedial (vmPFC) and dorsolateral prefrontal cortex (DLPFC). Finally, activation during residual vision, visual imagery and their interaction overlapped in the SPL, arguing for a central role of feeling in V1-independent vision and imagery.

  18. Patterns in cortical connectivity for determining outcomes in hand function after subcortical stroke.

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    Dazhi Yin

    Full Text Available BACKGROUND AND PURPOSE: Previous studies have noted changes in resting-state functional connectivity during motor recovery following stroke. However, these studies always uncover various patterns of motor recovery. Moreover, subgroups of stroke patients with different outcomes in hand function have rarely been studied. MATERIALS AND METHODS: We selected 24 patients who had a subcortical stroke in the left motor pathway and displayed only motor deficits. The patients were divided into two subgroups: completely paralyzed hands (CPH (12 patients and partially paralyzed hands (PPH (12 patients. Twenty-four healthy controls (HC were also recruited. We performed functional connectivity analysis in both the ipsilesional and contralesional primary motor cortex (M1 to explore the differences in the patterns between each pair of the three diagnostic groups. RESULTS: Compared with the HC, the PPH group displays reduced connectivity of both the ipsilesional and contralesional M1 with bilateral prefrontal gyrus and contralesional cerebellum posterior lobe. The connectivity of both the ipsilesional and contralesional M1 with contralateral primary sensorimotor cortex was reduced in the CPH group. Additionally, the connectivity of the ipsilesional M1 with contralesional postcentral gyrus, superior parietal lobule and ipsilesional inferior parietal lobule was reduced in the CPH group compared with the PPH group. Moreover, the connectivity of these regions was positively correlated with the Fugl-Meyer Assessment scores (hand+wrist across all stroke patients. CONCLUSIONS: Patterns in cortical connectivity may serve as a potential biomarker for the neural substratum associated with outcomes in hand function after subcortical stroke.

  19. Understanding the parietal lobe syndrome from a neurophysiological and evolutionary perspective.

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    Caminiti, Roberto; Chafee, Matthew V; Battaglia-Mayer, Alexandra; Averbeck, Bruno B; Crowe, David A; Georgopoulos, Apostolos P

    2010-06-01

    In human and nonhuman primates parietal cortex is formed by a multiplicity of areas. For those of the superior parietal lobule (SPL) there exists a certain homology between man and macaques. As a consequence, optic ataxia, a disturbed visual control of hand reaching, has similar features in man and monkeys. Establishing such correspondence has proven difficult for the areas of the inferior parietal lobule (IPL). This difficulty depends on many factors. First, no physiological information is available in man on the dynamic properties of cells in the IPL. Second, the number of IPL areas identified in the monkey is paradoxically higher than that so far described in man, although this issue will probably be reconsidered in future years, thanks to comparative imaging studies. Third, the consequences of parietal lesions in monkeys do not always match those observed in humans. This is another paradox if one considers that, in certain cases, the functional properties of neurons in the monkey's IPL would predict the presence of behavioral skills, such as construction capacity, that however do not seem to emerge in the wild. Therefore, constructional apraxia, which is well characterized in man, has never been described in monkeys and apes. Finally, only certain aspects, i.e. hand directional hypokinesia and gaze apraxia (Balint's psychic paralysis of gaze), of the multifaceted syndrome hemispatial neglect have been described in monkeys. These similarities, differences and paradoxes, among many others, make the study of the evolution and function of parietal cortex a challenging case.

  20. Language outcomes after resection of dominant inferior parietal lobule gliomas.

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    Southwell, Derek G; Riva, Marco; Jordan, Kesshi; Caverzasi, Eduardo; Li, Jing; Perry, David W; Henry, Roland G; Berger, Mitchel S

    2017-01-06

    OBJECTIVE The dominant inferior parietal lobule (IPL) contains cortical and subcortical regions essential for language. Although resection of IPL tumors could result in language deficits, little is known about the likelihood of postoperative language morbidity or the risk factors predisposing to this outcome. METHODS The authors retrospectively examined a series of patients who underwent resections of gliomas from the dominant IPL. Postoperative language outcomes were characterized across the patient population. To identify factors associated with postoperative language morbidity, the authors then compared features between those patients who experienced postoperative deficits and those who experienced no postoperative language dysfunction. RESULTS Twenty-four patients were identified for analysis. Long-term language deficits occurred in 29.2% of patients (7 of 24): 3 of these patients had experienced preoperative language deficits, whereas new long-term language deficits occurred in 4 patients (16.7%; 4 of 24). Of those patients who exhibited preoperative language deficits, 62.5% (5 of 8) experienced long-term resolution of their language deficits with surgical treatment. All patients underwent intraoperative brain mapping by direct electrical stimulation. Awake, intraoperative cortical language mapping was performed on 17 patients (70.8%). Positive cortical language sites were identified in 23.5% of these patients (4 of 17). Awake, intraoperative subcortical language mapping was performed in 8 patients (33.3%). Positive subcortical language sites were identified in 62.5% of these patients (5 of 8). Patients with positive cortical language sites exhibited a higher rate of long-term language deficits (3 of 4, 75%), compared with those who did not (1 of 13, 7.7%; p = 0.02). Although patients with positive subcortical language sites exhibited a higher rate of long-term language deficits than those who exhibited only negative sites (40.0% vs 0.0%, respectively), this

  1. Apraxia, pantomime and the parietal cortex

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    E. Niessen

    2014-01-01

    In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies and elderly neurological patients (typically included in structural lesion studies may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.

  2. Parietal Lobes in Schizophrenia: Do They Matter?

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    Yildiz, Murat; Borgwardt, Stefan J.; Berger, Gregor E.

    2011-01-01

    Objective. Despite observations that abnormal parietal lobe (PL) function is associated with psychotic-like experiences, our knowledge about the nature of PL involvement in schizophrenia is modest. The objective of this paper is to investigate the role of the PL in schizophrenia. Method. Medline databases were searched for English language publications using the following key words: parietal lobe, combined with schizophrenia, lesions, epilepsy, cognition, rare genetic disorders, MRI, fMRI, PET, and SPECT, respectively, followed by cross-checking of references. Results. Imaging studies in childhood onset schizophrenia suggest that grey matter abnormalities start in parietal and occipital lobes and proceed to frontal regions. Although, the findings are inconsistent, several studies with patients at risk to develop schizophrenia indicate early changes in the PL. Conclusions. We want to propose that in a proportion of individuals with emerging schizophrenia structural and functional alterations may start in the PL and progress to frontal regions. PMID:22937268

  3. Dynamic changes in phase-amplitude coupling facilitate spatial attention control in fronto-parietal cortex.

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    Sara M Szczepanski

    2014-08-01

    Full Text Available Attention is a core cognitive mechanism that allows the brain to allocate limited resources depending on current task demands. A number of frontal and posterior parietal cortical areas, referred to collectively as the fronto-parietal attentional control network, are engaged during attentional allocation in both humans and non-human primates. Numerous studies have examined this network in the human brain using various neuroimaging and scalp electrophysiological techniques. However, little is known about how these frontal and parietal areas interact dynamically to produce behavior on a fine temporal (sub-second and spatial (sub-centimeter scale. We addressed how human fronto-parietal regions control visuospatial attention on a fine spatiotemporal scale by recording electrocorticography (ECoG signals measured directly from subdural electrode arrays that were implanted in patients undergoing intracranial monitoring for localization of epileptic foci. Subjects (n = 8 performed a spatial-cuing task, in which they allocated visuospatial attention to either the right or left visual field and detected the appearance of a target. We found increases in high gamma (HG power (70-250 Hz time-locked to trial onset that remained elevated throughout the attentional allocation period over frontal, parietal, and visual areas. These HG power increases were modulated by the phase of the ongoing delta/theta (2-5 Hz oscillation during attentional allocation. Critically, we found that the strength of this delta/theta phase-HG amplitude coupling predicted reaction times to detected targets on a trial-by-trial basis. These results highlight the role of delta/theta phase-HG amplitude coupling as a mechanism for sub-second facilitation and coordination within human fronto-parietal cortex that is guided by momentary attentional demands.

  4. Apraxia, pantomime and the parietal cortex.

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    Niessen, E; Fink, G R; Weiss, P H

    2014-01-01

    Apraxia, a disorder of higher motor cognition, is a frequent and outcome-relevant sequel of left hemispheric stroke. Deficient pantomiming of object use constitutes a key symptom of apraxia and is assessed when testing for apraxia. To date the neural basis of pantomime remains controversial. We here review the literature and perform a meta-analysis of the relevant structural and functional imaging (fMRI/PET) studies. Based on a systematic literature search, 10 structural and 12 functional imaging studies were selected. Structural lesion studies associated pantomiming deficits with left frontal, parietal and temporal lesions. In contrast, functional imaging studies associate pantomimes with left parietal activations, with or without concurrent frontal or temporal activations. Functional imaging studies that selectively activated parietal cortex adopted the most stringent controls. In contrast to previous suggestions, current analyses show that both lesion and functional studies support the notion of a left-hemispheric fronto-(temporal)-parietal network underlying pantomiming object use. Furthermore, our review demonstrates that the left parietal cortex plays a key role in pantomime-related processes. More specifically, stringently controlled fMRI-studies suggest that in addition to storing motor schemas, left parietal cortex is also involved in activating these motor schemas in the context of pantomiming object use. In addition to inherent differences between structural and functional imaging studies and consistent with the dedifferentiation hypothesis, the age difference between young healthy subjects (typically included in functional imaging studies) and elderly neurological patients (typically included in structural lesion studies) may well contribute to the finding of a more distributed representation of pantomiming within the motor-dominant left hemisphere in the elderly.

  5. Cortical Activation during Action Observation, Action Execution, and Interpersonal Synchrony in Adults: A functional Near-Infrared Spectroscopy (fNIRS Study

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    Anjana N. Bhat

    2017-09-01

    Full Text Available Introduction: Humans engage in Interpersonal Synchrony (IPS as they synchronize their own actions with that of a social partner over time. When humans engage in imitation/IPS behaviors, multiple regions in the frontal, temporal, and parietal cortices are activated including the putative Mirror Neuron Systems (Iacoboni, 2005; Buxbaum et al., 2014. In the present study, we compared fNIRS-based cortical activation patterns across three conditions of action observation (“Watch” partner, action execution (“Do” on your own, and IPS (move “Together”.Methods: Fifteen typically developing adults completed a reach and cleanup task with the right arm while cortical activation was examined using a 24-channel, Hitachi fNIRS system. Each adult completed 8 trials across three conditions (Watch, Do, and Together. For each fNIRS channel, we obtained oxy hemoglobin (HbO2 and deoxy hemoglobin (HHb profiles. Spatial registration methods were applied to localize the cortical regions underneath each channel and to define six regions of interest (ROIs, right and left supero-anterior (SA or pre/post-central gyri, infero-posterior (IP or angular/supramarginal gyri, and infero-anterior (IA or superior/middle temporal gyri regions.Results: In terms of task-related differences, the majority of the ROIs were more active during Do and Together compared to Watch. Only the right/ipsilateral fronto-parietal and inferior parietal cortices had greater activation during Together compared to Do.Conclusions: The similarities in cortical activation between action execution and IPS suggest that neural control of IPS is more similar to its execution than observational aspects. To be clear, the more complex the actions performed, the more difficult the IPS behaviors. Secondly, IPS behaviors required slightly more right-sided activation (vs. execution/observation suggesting that IPS is a higher-order process involving more bilateral activation compared to its sub

  6. Cortical Activation during Action Observation, Action Execution, and Interpersonal Synchrony in Adults: A functional Near-Infrared Spectroscopy (fNIRS) Study.

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    Bhat, Anjana N; Hoffman, Michael D; Trost, Susanna L; Culotta, McKenzie L; Eilbott, Jeffrey; Tsuzuki, Daisuke; Pelphrey, Kevin A

    2017-01-01

    Introduction: Humans engage in Interpersonal Synchrony (IPS) as they synchronize their own actions with that of a social partner over time. When humans engage in imitation/IPS behaviors, multiple regions in the frontal, temporal, and parietal cortices are activated including the putative Mirror Neuron Systems (Iacoboni, 2005; Buxbaum et al., 2014). In the present study, we compared fNIRS-based cortical activation patterns across three conditions of action observation ("Watch" partner), action execution ("Do" on your own), and IPS (move "Together"). Methods: Fifteen typically developing adults completed a reach and cleanup task with the right arm while cortical activation was examined using a 24-channel, Hitachi fNIRS system. Each adult completed 8 trials across three conditions (Watch, Do, and Together). For each fNIRS channel, we obtained oxy hemoglobin (HbO2) and deoxy hemoglobin (HHb) profiles. Spatial registration methods were applied to localize the cortical regions underneath each channel and to define six regions of interest (ROIs), right and left supero-anterior (SA or pre/post-central gyri), infero-posterior (IP or angular/supramarginal gyri), and infero-anterior (IA or superior/middle temporal gyri) regions. Results: In terms of task-related differences, the majority of the ROIs were more active during Do and Together compared to Watch. Only the right/ipsilateral fronto-parietal and inferior parietal cortices had greater activation during Together compared to Do. Conclusions: The similarities in cortical activation between action execution and IPS suggest that neural control of IPS is more similar to its execution than observational aspects. To be clear, the more complex the actions performed, the more difficult the IPS behaviors. Secondly, IPS behaviors required slightly more right-sided activation (vs. execution/observation) suggesting that IPS is a higher-order process involving more bilateral activation compared to its sub-components. These findings

  7. TMS investigations into the task-dependent functional interplay between human posterior parietal and motor cortex.

    Science.gov (United States)

    Koch, Giacomo; Rothwell, John C

    2009-09-14

    Transcranial magnetic stimulation (TMS) can be used in two different ways to investigate the contribution of cortical areas involved in grasp/reach movements in humans. It can produce "virtual lesions" that interfere with activity in particular cortical areas at specific times during a task, or it can be used in a twin coil design to test the excitability of cortical projections to M1 at different times during a task. The former method has described how cortical structures such as the ventral premotor cortex (PMv), dorsal premotor cortex (PMd) and the anterior intraparietal sulcus (aIPS) are important for specific aspects of reaching, grasping and lifting objects. In the latter method, a conditioning stimulus (CS) is first used to activate putative pathways to the motor cortex from, for example, posterior parietal cortex (PPC) or PMd, while a second, test stimulus (TS), delivered over the primary motor cortex a few ms later probes any changes in excitability that are produced by the input. Thus changes in the effectiveness of the conditioning pulse give an indication of how the excitability of the connection changes over time and during a specific task. Here we review studies describing the time course of operation of parallel intracortical circuits and cortico-cortical connections between the PMd, PMv, PPC and M1, thus demonstrating that functional interplay between these areas and the primary motor cortices is not fixed, but can change in a highly task-, condition- and time-dependent manner.

  8. Sodium valproate use is associated with reduced parietal lobe thickness and brain volume.

    Science.gov (United States)

    Pardoe, Heath R; Berg, Anne T; Jackson, Graeme D

    2013-05-14

    We hypothesized that total brain volume, white matter volume, and lobar cortical thickness would be different in epilepsy patients. We studied valproate relative to nonvalproate by using patients with epilepsy and healthy controls. Patients with focal intractable epilepsy from a tertiary epilepsy center were the primary group for analysis. A confirmatory analysis was carried out in an independent group of subjects imaged as part of a community-based study of childhood-onset epilepsy. Total brain volume; white matter volume; and frontal, parietal, occipital, and temporal lobe thickness were measured by processing whole-brain T1-weighted MRI using FreeSurfer 5.1. Total brain volume, white matter volume, and parietal thickness were reduced in the valproate group relative to controls and nonvalproate users (valproate, n = 9; nonvalproate, n = 27; controls, n = 45; all male). These findings were confirmed in an independent group (valproate, n = 7; nonvalproate, n = 70; controls, n = 20; all male). Sodium valproate use in epilepsy is associated with parietal lobe thinning, reduced total brain volume, and reduced white matter volume. This study provides Class IV evidence that use of valproate in epilepsy is associated with reduced parietal lobe thickness, total brain volume, and white matter volume.

  9. Cross-frequency power correlations reveal the right superior temporal gyrus as a hub region during working memory maintenance.

    Science.gov (United States)

    Park, Hyojin; Kang, Eunjoo; Kang, Hyejin; Kim, June Sic; Jensen, Ole; Chung, Chun Kee; Lee, Dong Soo

    2011-01-01

    In the present study, we characterized within- and cross-frequency power correlations from magnetoencephalography (MEG) data in order to understand how different brain regions cooperate as a network to maintain working memory representations with several features. The working memory items were composed of spatially arranged dots supposedly requiring both the dorsal and the ventral stream to be engaged during maintenance. Using a beamforming technique, we localized memory-dependent sources in the alpha, beta, and gamma bands. After the single-trial power values were extracted from these frequency bands with respect to each source, we calculated the correlations within- and cross-frequency bands. The following general picture emerged: gamma power in right superior temporal gyrus (STG) during working memory maintenance was correlated with numerous other sources in the alpha band in prefrontal, parietal, and posterior regions. In addition, the power correlations within the alpha band showed correlations across posterior-parietal-frontal regions. From these findings, we suggest that the STG dominated by gamma activity serves as a hub region for the network nodes responsible for the retention of the stimulus used in this study, which is likely to depend on both the "where-" and the "what-" visual system simultaneously. The present study demonstrates how oscillatory dynamics reflecting the interaction between cortical areas can be investigated by means of cross-frequency power correlations in source space. This methodological framework could be of general utility when studying functional network properties of the working brain.

  10. Acute hepatic encephalopathy presenting as cortical laminar necrosis: case report.

    Science.gov (United States)

    Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young

    2013-01-01

    We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

  11. Acute hepatic encephalopathy presenting as cortical laminar necrosis: Case report

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong Mun; Kim, Yoon Hee; Roh, Sook Young [Bundang Jesaeng General Hospital, Daejin Medical Center, Seongnam (Korea, Republic of)

    2013-04-15

    We report on a 55-year-old man with alcoholic liver cirrhosis who presented with status epilepticus. Laboratory analysis showed markedly elevated blood ammonia. Brain magnetic resonance imaging (MRI) showed widespread cortical signal changes with restricted diffusion, involving both temporo-fronto-parietal cortex, while the perirolandic regions and occipital cortex were uniquely spared. A follow-up brain MRI demonstrated diffuse cortical atrophy with increased signals on T1-weighted images in both the basal ganglia and temporal lobe cortex, representing cortical laminar necrosis. We suggest that the brain lesions, in our case, represent a consequence of toxic effect of ammonia.

  12. Radiation-induced abnormal cortical thickness in patients with nasopharyngeal carcinoma after radiotherapy

    Directory of Open Access Journals (Sweden)

    Jiabao Lin

    2017-01-01

    Full Text Available Conventional MRI studies showed that radiation-induced brain necrosis in patients with nasopharyngeal carcinoma (NPC in years after radiotherapy (RT could involve brain gray matter (GM and impair brain function. However, it is still unclear the radiation-induced brain morphological changes in NPC patients with normal-appearing GM in the early period after RT. In this study, we acquired high-resolution brain structural MRI data from three groups of patients, 22 before radiotherapy (pre-RT NPC patients with newly diagnosed but not yet medically treated, 22 NPC patients in the early-delayed stage after radiotherapy (post-RT-ED, and 20 NPC patients in the late-delayed stage after radiotherapy (post-RT-LD, and then analyzed the radiation-induced cortical thickness alteration in NPC patients after RT. Using a vertex-wise surface-based morphometry (SBM approach, we detected significantly decreased cortical thickness in the precentral gyrus (PreCG in the post-RT-ED group compared to the pre-RT group. And the post-RT-LD group showed significantly increased cortical thickness in widespread brain regions, including the bilateral inferior parietal, left isthmus of the cingulate, left bank of the superior temporal sulcus and left lateral occipital regions, compared to the pre-RT group, and in the bilateral PreCG compared to the post-RT-ED group. Similar analysis with ROI-wise SBM method also found the consistent results. These results indicated that radiation-induced brain injury mainly occurred in the post-RT-LD group and the cortical thickness alterations after RT were dynamic in different periods. Our findings may reflect the pathogenesis of radiation-induced brain injury in NPC patients with normal-appearing GM and an early intervention is necessary for protecting GM during RT.

  13. A longitudinal study of atrophy in amnestic mild cognitive impairment and normal aging revealed by cortical thickness.

    Directory of Open Access Journals (Sweden)

    Zhijun Yao

    Full Text Available In recent years, amnestic mild cognitive impairment (aMCI has attracted significant attention as an indicator of high risk for Alzheimer's disease. An understanding of the pathology of aMCI may benefit the development of effective clinical treatments for dementia. In this work, we measured the cortical thickness of 109 aMCI subjects and 99 normal controls (NC twice over two years. The longitudinal changes and the cross-sectional differences between the two types of participants were explored using the vertex thickness values. The thickness of the cortex in aMCI was found significantly reduced in both longitudinal and between-group comparisons, mainly in the temporal lobe, superolateral parietal lobe and some regions of the frontal cortices. Compared to NC, the aMCI showed a significantly high atrophy rate in the left lateral temporal lobe and left parahippocampal gyrus over two years. Additionally, a significant positive correlation between brain atrophy and the decline of Mini-Mental State Examination (MMSE scores was also found in the left superior and left middle temporal gyrus in aMCI. These findings demonstrated specific longitudinal spatial patterns of cortical atrophy in aMCI and NC. The higher atrophy rate in aMCI might be responsible for the accelerated functional decline in the aMCI progression process.

  14. A longitudinal study of atrophy in amnestic mild cognitive impairment and normal aging revealed by cortical thickness.

    Science.gov (United States)

    Yao, Zhijun; Hu, Bin; Liang, Chuanjiang; Zhao, Lina; Jackson, Mike

    2012-01-01

    In recent years, amnestic mild cognitive impairment (aMCI) has attracted significant attention as an indicator of high risk for Alzheimer's disease. An understanding of the pathology of aMCI may benefit the development of effective clinical treatments for dementia. In this work, we measured the cortical thickness of 109 aMCI subjects and 99 normal controls (NC) twice over two years. The longitudinal changes and the cross-sectional differences between the two types of participants were explored using the vertex thickness values. The thickness of the cortex in aMCI was found significantly reduced in both longitudinal and between-group comparisons, mainly in the temporal lobe, superolateral parietal lobe and some regions of the frontal cortices. Compared to NC, the aMCI showed a significantly high atrophy rate in the left lateral temporal lobe and left parahippocampal gyrus over two years. Additionally, a significant positive correlation between brain atrophy and the decline of Mini-Mental State Examination (MMSE) scores was also found in the left superior and left middle temporal gyrus in aMCI. These findings demonstrated specific longitudinal spatial patterns of cortical atrophy in aMCI and NC. The higher atrophy rate in aMCI might be responsible for the accelerated functional decline in the aMCI progression process.

  15. Decoding the view expectation during learned maze navigation from human fronto-parietal network.

    Science.gov (United States)

    Shikauchi, Yumi; Ishii, Shin

    2015-12-03

    Humans use external cues and prior knowledge about the environment to monitor their positions during spatial navigation. View expectation is essential for correlating scene views with a cognitive map. To determine how the brain performs view expectation during spatial navigation, we applied a multiple parallel decoding technique to functional magnetic resonance imaging (fMRI) when human participants performed scene choice tasks in learned maze navigation environments. We decoded participants' view expectation from fMRI signals in parietal and medial prefrontal cortices, whereas activity patterns in occipital cortex represented various types of external cues. The decoder's output reflected participants' expectations even when they were wrong, corresponding to subjective beliefs opposed to objective reality. Thus, view expectation is subjectively represented in human brain, and the fronto-parietal network is involved in integrating external cues and prior knowledge during spatial navigation.

  16. Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex

    Science.gov (United States)

    Degnan, Andrew J.; Wisnowski, Jessica L.; Choi, SoYoung; Ceschin, Rafael; Bhushan, Chitresh; Leahy, Richard M.; Corby, Patricia; Schmithorst, Vincent J.; Panigrahy, Ashok

    2015-01-01

    Objective Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN), which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth. Methods Thirty-eight preadolescents (ages 9–13; 19 born in the late preterm period (≥32 weeks gestational age) and 19 at term) without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI). Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus) and lateral parietal DMN (superior marginal and angular gyri). Results Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC). Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups. Conclusion Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks

  17. Altered Structural and Functional Connectivity in Late Preterm Preadolescence: An Anatomic Seed-Based Study of Resting State Networks Related to the Posteromedial and Lateral Parietal Cortex.

    Directory of Open Access Journals (Sweden)

    Andrew J Degnan

    Full Text Available Late preterm birth confers increased risk of developmental delay, academic difficulties and social deficits. The late third trimester may represent a critical period of development of neural networks including the default mode network (DMN, which is essential to normal cognition. Our objective is to identify functional and structural connectivity differences in the posteromedial cortex related to late preterm birth.Thirty-eight preadolescents (ages 9-13; 19 born in the late preterm period (≥32 weeks gestational age and 19 at term without access to advanced neonatal care were recruited from a low socioeconomic status community in Brazil. Participants underwent neurocognitive testing, 3-dimensional T1-weighted imaging, diffusion-weighted imaging and resting state functional MRI (RS-fMRI. Seed-based probabilistic diffusion tractography and RS-fMRI analyses were performed using unilateral seeds within the posterior DMN (posterior cingulate cortex, precuneus and lateral parietal DMN (superior marginal and angular gyri.Late preterm children demonstrated increased functional connectivity within the posterior default mode networks and increased anti-correlation with the central-executive network when seeded from the posteromedial cortex (PMC. Key differences were demonstrated between PMC components with increased anti-correlation with the salience network seen only with posterior cingulate cortex seeding but not with precuneus seeding. Probabilistic tractography showed increased streamlines within the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus within late preterm children while decreased intrahemispheric streamlines were also observed. No significant differences in neurocognitive testing were demonstrated between groups.Late preterm preadolescence is associated with altered functional connectivity from the PMC and lateral parietal cortex to known distributed functional cortical networks despite no significant

  18. Bilateral, posterior parietal polymicrogyria as part of speech therapy ...

    African Journals Online (AJOL)

    Bilateral, posterior parietal polymicrogyria as part of speech therapy work-up. ... units to make the diagnosis of bilateral posterior parietal polymicrogyria in a child with speech pathology. ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  19. Severity of Cortical Thinning Correlates With Schizophrenia Spectrum Symptoms

    Science.gov (United States)

    Greenstein, Deanna; Shora, Lorie; Dillard-Broadnax, Diane; Gochman, Peter; Clasen, Liv S.; Berman, Rebecca A.; Rapoport, Judith L.; Gogtay, Nitin; Ordóñez, Anna E.

    2016-01-01

    Objective This study investigated the relationship between regional cortical gray matter thinning and symptoms of schizophrenia spectrum personality disorders (PDs) in siblings of patients with childhood-onset schizophrenia (COS). Method 66 siblings of patients with COS were assessed for symptoms of schizophrenia spectrum PDs (avoidant, paranoid, schizoid, schizotypal). Structural magnetic resonance images were obtained at approximately 2-year intervals from the siblings and from 62 healthy volunteers, matched for age, sex, ethnicity, and handedness. Cortical thickness measures were extracted. Mixed effect regression models were used to test the relationship between symptoms and cortical gray matter thickness. Cortical thinning was also tested longitudinally in healthy volunteers and siblings. Results Cortical thinning was found to correlate with symptoms of schizotypal and, to a lesser extent, schizoid PDs. Thinning was most pronounced in the left temporal and parietal lobes and right frontal and parietal regions. Gray matter loss was found to be continuous with that measured in COS. Longitudinal thinning trajectories were found not to differ between siblings and healthy volunteers. Conclusion The present investigation of cortical thinning in siblings of patients with COS indicates that symptoms of schizophrenia spectrum PDs correlate with regional gray matter loss. This finding supports the idea of cortical thinning as a schizophrenia endophenotype. PMID:26802780

  20. Influence of bone microstructure on the mechanical properties of skull cortical bone - A combined experimental and computational approach.

    Science.gov (United States)

    Boruah, Sourabh; Subit, Damien L; Paskoff, Glenn R; Shender, Barry S; Crandall, Jeff R; Salzar, Robert S

    2017-01-01

    The strength and compliance of the dense cortical layers of the human skull have been examined since the beginning of the 20th century with the wide range in the observed mechanical properties attributed to natural biological variance. Since this variance may be explained by the difference in structural arrangement of bone tissue, micro-computed tomography (µCT) was used in conjunction with mechanical testing to study the relationship between the microstructure of human skull cortical coupons and their mechanical response. Ninety-seven bone samples were machined from the cortical tables of the calvaria of ten fresh post mortem human surrogates and tested in dynamic tension until failure. A linear response between stress and strain was observed until close to failure, which occurred at 0.6% strain on average. The effective modulus of elasticity for the coupons was 12.01 ± 3.28GPa. Porosity of the test specimens, determined from µCT, could explain only 51% of the variation of their effective elastic modulus. Finite element (FE) models of the tested specimens built from µCT images indicated that modeling the microstructural arrangement of the bone, in addition to the porosity, led to a marginal improvement of the coefficient of determination to 54%. Modulus for skull cortical bone for an element size of 50µm was estimated to be 19GPa at an average. Unlike the load bearing bones of the body, almost half of the variance in the mechanical properties of cortical bone from the skull may be attributed to differences at the sub-osteon (< 50µm) level. ANOVA tests indicated that effective failure stress and strain varied significantly between the frontal and parietal bones, while the bone phase modulus was different for the superior and inferior aspects of the calvarium. The micro FE models did not indicate any anisotropy attributable to the pores observable under µCT.

  1. Cortical thinning in former professional soccer players.

    Science.gov (United States)

    Koerte, Inga K; Mayinger, Michael; Muehlmann, Marc; Kaufmann, David; Lin, Alexander P; Steffinger, Denise; Fisch, Barbara; Rauchmann, Boris-Stephan; Immler, Stefanie; Karch, Susanne; Heinen, Florian R; Ertl-Wagner, Birgit; Reiser, Maximilian; Stern, Robert A; Zafonte, Ross; Shenton, Martha E

    2016-09-01

    Soccer is the most popular sport in the world. Soccer players are at high risk for repetitive subconcussive head impact when heading the ball. Whether this leads to long-term alterations of the brain's structure associated with cognitive decline remains unknown. The aim of this study was to evaluate cortical thickness in former professional soccer players using high-resolution structural MR imaging. Fifteen former male professional soccer players (mean age 49.3 [SD 5.1] years) underwent high-resolution structural 3 T MR imaging, as well as cognitive testing. Fifteen male, age-matched former professional non-contact sport athletes (mean age 49.6 [SD 6.4] years) served as controls. Group analyses of cortical thickness were performed using voxel-based statistics. Soccer players demonstrated greater cortical thinning with increasing age compared to controls in the right inferolateral-parietal, temporal, and occipital cortex. Cortical thinning was associated with lower cognitive performance as well as with estimated exposure to repetitive subconcussive head impact. Neurocognitive evaluation revealed decreased memory performance in the soccer players compared to controls. The association of cortical thinning and decreased cognitive performance, as well as exposure to repetitive subconcussive head impact, further supports the hypothesis that repetitive subconcussive head impact may play a role in early cognitive decline in soccer players. Future studies are needed to elucidate the time course of changes in cortical thickness as well as their association with impaired cognitive function and possible underlying neurodegenerative process.

  2. User-driven control increases cortical activity during treadmill walking: an EEG study.

    Science.gov (United States)

    Bulea, Thomas C; Jonghyun Kim; Damiano, Diane L; Stanley, Christopher J; Hyung-Soon Park

    2014-01-01

    Treadmills provide a safe and efficient method for gait rehabilitation but treadmill based training paradigms have not been shown to create superior results when compared with traditional physical therapy methods such as overground training. One explanation for this may be that walking at a constant, fixed speed requires little mental engagement from the user, which has been postulated as a key factor in the success of motor learning. To increase mental engagement, we developed a user-driven treadmill control scheme. In this paper we use electroencephalography (EEG) to compare cortical activity during user-driven (active) walking with activity on a normal (passive) treadmill in nine healthy subjects. We used independent component analysis (ICA) to isolate brain activity from artifactual components. We fit equivalent dipole sources to each brain component and clustered these across subjects. Our analysis revealed that relative to the passive treadmill, active walking resulted in statistically significant decreases in spectral power, i.e. desynchronization, in the anterior cingulate, sensorimotor cortices, and posterior parietal lobe of the cortex. These results indicate that user-driven treadmills more fully engage the motor cortex and therefore could facilitate better training outcomes than a traditional treadmill.

  3. Repetitive transcranial magnetic stimulation affects behavior by biasing endogenous cortical oscillations

    Directory of Open Access Journals (Sweden)

    Massihullah Hamidi

    2009-06-01

    Full Text Available A governing assumption about repetitive transcranial magnetic stimulation (rTMS has been that it interferes with task-related neuronal activity – in effect, by “injecting noise” into the brain – and thereby disrupts behavior. Recent reports of rTMS-produced behavioral enhancement, however, call this assumption into question. We investigated the neurophysiological effects of rTMS delivered during the delay period of a visual working memory task by simultaneously recording brain activity with electroencephalography (EEG. Subjects performed visual working memory for locations or for shapes, and in half the trials a 10-Hz train of rTMS was delivered to the superior parietal lobule or a control brain area. The wide range of individual differences in the effects of rTMS on task accuracy, from improvement to impairment, was predicted by individual differences in the effect of rTMS on power in the alpha-band of the EEG (~ 10 Hz: a decrease in alpha-band power corresponded to improved performance, whereas an increase in alpha-band power corresponded to the opposite. The EEG effect was localized to cortical sources encompassing the frontal eye fields and the intraparietal sulcus, and was specific to task (location, but not object memory and to rTMS target (superior parietal lobule, not control area. Furthermore, for the same task condition, rTMS-induced changes in cross-frequency phase synchrony between alpha- and gamma-band (> 40 Hz oscillations predicted changes in behavior. These results suggest that alpha-band oscillations play an active role cognitive processes and do not simply reflect absence of processing. Furthermore, this study shows that the complex effects of rTMS on behavior can result from biasing endogenous patterns of network-level oscillations.

  4. Social distance evaluation in human parietal cortex.

    Science.gov (United States)

    Yamakawa, Yoshinori; Kanai, Ryota; Matsumura, Michikazu; Naito, Eiichi

    2009-01-01

    Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. "close friends" "high lord"). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space.

  5. Parietal wall endometriosis: a rare case report

    Directory of Open Access Journals (Sweden)

    Mahija Sahu

    2015-04-01

    Full Text Available A 28 year old P2L1 with one previous cesarean presented with cyclical pain in periumblical area just below umbilicus for 1 year with USG finding suggestive of parietal wall endometriosis planned for surgery on her 2nd day of menstruation. She underwent diagnostic laparoscopy with complete excision of endometrioma. Diagnostic laparoscopy showed no evidence of endometrioma in the pelvic cavity except for omental adhesion at parietal wall endometrioma site, adhesiolysis of omentum, mesh repair of rectus sheath defect done. She is followed up for last 3 cycles post-operative and has no cyclical pain further. [Int J Reprod Contracept Obstet Gynecol 2015; 4(2.000: 524-526

  6. Deficits of Motor Intention following Parietal Lesions

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    Christopher L. Gore

    2002-01-01

    Full Text Available Patients with lesions to the right parietal lobe were tested on their ability to reach to targets, or to respond verbally to targets. The targets occurred at the same two spatial locations -- to the left and right of the patient—with the task being cued by the color of the target. Patients were able to perform both tasks separately rapidly and without error. However, when the two tasks were interleaved, they had difficulty making a response in the left (contralesional field when this was different to a response that they had just made. These results suggest that lesions to the parietal cortex may cause a deficit in the coding for motor intention, as well as attention in the contralesional field.

  7. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Directory of Open Access Journals (Sweden)

    Kai Yuan

    Full Text Available Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18 and age-, education- and gender-matched controls (n = 18 were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC, insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  8. Cortical thickness abnormalities in late adolescence with online gaming addiction.

    Science.gov (United States)

    Yuan, Kai; Cheng, Ping; Dong, Tao; Bi, Yanzhi; Xing, Lihong; Yu, Dahua; Zhao, Limei; Dong, Minghao; von Deneen, Karen M; Liu, Yijun; Qin, Wei; Tian, Jie

    2013-01-01

    Online gaming addiction, as the most popular subtype of Internet addiction, had gained more and more attention from the whole world. However, the structural differences in cortical thickness of the brain between adolescents with online gaming addiction and healthy controls are not well unknown; neither was its association with the impaired cognitive control ability. High-resolution magnetic resonance imaging scans from late adolescence with online gaming addiction (n = 18) and age-, education- and gender-matched controls (n = 18) were acquired. The cortical thickness measurement method was employed to investigate alterations of cortical thickness in individuals with online gaming addiction. The color-word Stroop task was employed to investigate the functional implications of the cortical thickness abnormalities. Imaging data revealed increased cortical thickness in the left precentral cortex, precuneus, middle frontal cortex, inferior temporal and middle temporal cortices in late adolescence with online gaming addiction; meanwhile, the cortical thicknesses of the left lateral orbitofrontal cortex (OFC), insula, lingual gyrus, the right postcentral gyrus, entorhinal cortex and inferior parietal cortex were decreased. Correlation analysis demonstrated that the cortical thicknesses of the left precentral cortex, precuneus and lingual gyrus correlated with duration of online gaming addiction and the cortical thickness of the OFC correlated with the impaired task performance during the color-word Stroop task in adolescents with online gaming addiction. The findings in the current study suggested that the cortical thickness abnormalities of these regions may be implicated in the underlying pathophysiology of online gaming addiction.

  9. Eclamptogenic Gerstmann's syndrome in combination with cortical agnosia and cortical diplopia.

    Science.gov (United States)

    Käsmann, B; Ruprecht, K W

    1995-07-01

    Cortical blindness is defined as a loss of vision due to bilateral retrogeniculate lesions (geniculocalcarine blindness). Gerstmann's syndrome is a combination of disorientation for left and right, finger agnosia, and profound agraphia, alexia, and acalculia. It is due to a lesion in the left angular gyrus, situated at the confluence of the temporal, parietal, and occipital lobes. We report on a patient who suffered from severe underdiagnosed eclampsia and who developed bilateral extensive medial temporal, parietal, and calcarine ischemic infarctions during an eclamptic fit. In addition, ischemia destroyed the left angular gyrus. The combination of these lesions led to Gerstmann's syndrome with additional cortical agnosia and cortical diplopia. For the first few months following the ischemic insult, the patient had been cortically blind. Thereafter, the patient slowly regained a visual acuity of 0.1 in both eyes. She then experienced monocular and binocular diplopia. Her ocular motility was normal; there was no phoria or tropia. Monocular and binocular diplopia slowly became less severe over the following year. Now, 2 years after the incident, the patient has a visual acuity of 0.2 in both eyes and no double vision. However, the handicapping symptoms of Gerstmann's syndrome, which make leading a normal life impossible, have persisted--the patient still cannot cope alone, mainly due to the severe disorientation for left and right. The picture of cortical agnosia, cortical diplopia, and Gerstmann's syndrome is a very rare combination. Visual recovery and rehabilitation in cortical blindness are severely affected and made difficult by the symptoms of Gerstmann's syndrome. In our case the reason for such a dramatic clinical picture was eclampsia, whose prodomes had not been diagnosed in time.

  10. Is the Posterior Parietal Lobe Involved in Working Memory Retrieval? Evidence from Patients with Bilateral Parietal Lobe Damage

    OpenAIRE

    Marian E Berryhill; Olson, Ingrid R.

    2008-01-01

    Neuroimaging evidence suggests that the parietal lobe has an important role in memory retrieval, yet neuropsychology is largely silent on this topic. Recently, we reported that unilateral parietal lobe damage impairs various forms of visual working memory when tested by old/new recognition. Here, we investigate whether parietal lobe working memory deficits are linked to problems at retrieval. We tested two patients with bilateral parietal lobe damage in a series of visual working memory tasks...

  11. Is the posterior parietal lobe involved in working memory retrieval? Evidence from patients with bilateral parietal lobe damage

    OpenAIRE

    Berryhill, M.E; Olson, I.R.

    2008-01-01

    Neuroimaging evidence suggests that the parietal lobe has an important role in memory retrieval, yet neuropsychology is largely silent on this topic. Recently, we reported that unilateral parietal lobe damage impairs various forms of visual working memory when tested by old/new recognition. Here, we investigate whether parietal lobe working memory deficits are linked to problems at retrieval. We tested two patients with bilateral parietal lobe damage in a series of visual working memory tasks...

  12. Discrete object representation, attention switching, and task difficulty in the parietal lobe.

    Science.gov (United States)

    Cusack, Rhodri; Mitchell, Daniel J; Duncan, John

    2010-01-01

    An important component of perception, attention, and memory is the structuring of information into subsets ("objects"), which allows some parts to be considered together but kept separate from others. Portions of the posterior parietal lobe respond proportionally to the number of objects in the scope of attention and short-term memory, up to a capacity limit of around four, suggesting they have a role in this important process. This study investigates the relationship of discrete object representation to other parietal functions. Two experiments and two supplementary analyses were conducted to evaluate responsivity in parietal regions to the number of objects, the number of spatial locations, attention switching, and general task difficulty. Using transparent motion, it was found that a posterior and inferior parietal response to multiple objects persists even in the absence of a change in visual extent or the number of spatial locations. In a monitoring task, it was found that attention switching (or task difficulty) and object representation have distinct neural signatures, with the former showing greater recruitment of an anterior and lateral intraparietal sulcus (IPS) region, but the latter in a posterior and lateral region. A dissociation was also seen between selectivity for object load across tasks in the inferior IPS and feature or object-related memory load in the superior IPS.

  13. Neural correlate of subjective sensory experience gradually builds up across cortical areas

    Science.gov (United States)

    de Lafuente, Victor; Romo, Ranulfo

    2006-01-01

    When a sensory stimulus is presented, many cortical areas are activated, but how does the representation of a sensory stimulus evolve in time and across cortical areas during a perceptual judgment? We investigated this question by analyzing the responses from single neurons, recorded in several cortical areas of parietal and frontal lobes, while trained monkeys reported the presence or absence of a mechanical vibration of varying amplitude applied to the skin of one fingertip. Here we show that the strength of the covariations between neuronal activity and perceptual judgments progressively increases across cortical areas as the activity is transmitted from the primary somatosensory cortex to the premotor areas of the frontal lobe. This finding suggests that the neuronal correlates of subjective sensory experience gradually build up across somatosensory areas of the parietal lobe and premotor cortices of the frontal lobe. PMID:16924098

  14. Anatomical coupling among distributed cortical regions in youth varies as a function of individual differences in vocabulary abilities.

    Science.gov (United States)

    Lee, Nancy Raitano; Raznahan, Armin; Wallace, Gregory L; Alexander-Bloch, Aaron; Clasen, Liv S; Lerch, Jason P; Giedd, Jay N

    2014-05-01

    Patient lesion and functional magnetic resonance imaging (fMRI) studies have provided convincing evidence that a distributed brain network subserves word knowledge. However, little is known about the structural correlates of this network within the context of typical development and whether anatomical coupling in linguistically relevant regions of cortex varies as a function of vocabulary skill. Here we investigate the association between vocabulary and anatomical coupling in 235 typically developing youth (ages 6-19 years) using structural MRI. The study's primary aim was to evaluate whether higher vocabulary performance was associated with greater vertex-level cortical thickness covariation in distributed regions of cortex known to be associated with word knowledge. Results indicate that better vocabulary skills are associated with greater anatomical coupling in several linguistically relevant regions of cortex, including the left inferior parietal (temporal-parietal junction), inferior temporal, middle frontal, and superior frontal gyri and the right inferior frontal and precentral gyri. Furthermore, in high vocabulary scorers, stronger coupling is found among these regions. Thus, complementing patient and fMRI studies, this is the first investigation to highlight the relevance of anatomical covariance within the cortex to vocabulary skills in typically developing youth, further elucidating the distributed nature of neural systems subserving word knowledge.

  15. Atypical parietal lobe activity to subliminal faces in youth with a family history of alcoholism.

    Science.gov (United States)

    Peraza, Jennifer; Cservenka, Anita; Herting, Megan M; Nagel, Bonnie J

    2015-03-01

    Adults with alcohol use disorders (AUDs) show different behavioral and neurological functioning during emotional processing tasks from healthy controls. Adults with a family history (FHP) of AUD also show different activation in limbic brain areas, such as the amygdala. However, it is unclear if this pattern exists during adolescence before any episodes of heavy alcohol use. We hypothesized that the amygdalar response to subliminally-presented fearful faces would be reduced in FHP adolescents compared to peers who were family history negative (FHN) for AUD. An adapted Masked Faces paradigm was used to examine blood oxygen level-dependent response to subliminal fearful vs. neutral faces in 14 FHP (6 females, 8 males) and 15 FHN (6 females, 9 males) youth, ages 11-15 years. Both FHP and FHN youth had no history of heavy alcohol consumption. A significant difference was seen between groups in the left superior parietal lobule FHN youth showed deactivation to fearful and neutral masked faces compared to baseline, whereas FHP youth showed deactivation only to fearful masked faces. No significant differences in amygdalar activation were seen between groups. The left superior parietal lobule is part of the fronto-parietal network, which has been implicated in attentional control. Lack of reduced neural activity to neutral faces among FHP youth may represent differences in suppressing attention networks to less salient emotional stimuli, or perhaps, a higher threshold of saliency for emotional stimuli among at-risk youth.

  16. Morbidity profile following aggressive resection of parietal lobe gliomas.

    Science.gov (United States)

    Sanai, Nader; Martino, Juan; Berger, Mitchel S

    2012-06-01

    The impact of parietal lobe gliomas is typically studied in the context of parietal lobe syndromes. However, critical language pathways traverse the parietal lobe and are susceptible during tumor resection. The authors of this study reviewed their experience with parietal gliomas to characterize the impact of resection and the morbidity associated with language. The study population included adults who had undergone resection of parietal gliomas of all grades. Tumor location was identified according to a proposed classification system for parietal region gliomas. Low- and high-grade tumors were volumetrically analyzed using FLAIR and T1-weighted contrast-enhanced MR imaging. One hundred nineteen patients with parietal gliomas were identified--34 with low-grade gliomas and 85 with high-grade gliomas. The median patient age was 45 years, and most patients (53) presented with seizures, whereas only 4 patients had an appreciable parietal lobe syndrome. The median preoperative tumor volume was 31.3 cm(3), the median extent of resection was 96%, and the median postoperative tumor volume was 0.9 cm(3). Surprisingly, the most common early postoperative neurological deficit was dysphasia (16 patients), not weakness (12 patients), sensory deficits (14 patients), or parietal lobe syndrome (10 patients). A proposed parietal glioma classification system, based on surgical anatomy, was predictive of language deficits. This is the largest reported experience with parietal lobe gliomas. The findings suggested that parietal language pathways are compromised at a surprisingly high rate. The proposed parietal glioma classification system is predictive of postoperative morbidity associated with language and can assist with preoperative planning. Taken together, these data emphasize the value of identifying language pathways when operating within the parietal lobe.

  17. Theta and Alpha Oscillations during the Retention Period of Working Memory by rTMS Stimulating the Parietal Lobe

    Directory of Open Access Journals (Sweden)

    Song Li

    2017-09-01

    Full Text Available Studies on repetitive transcranial magnetic stimulation (rTMS have shown that stimulating the parietal lobe, which plays a role in memory storage, can enhance performance during the “retention” process of working memory (WM. However, the mechanism of rTMS effect during this phase is still unclear. In this study, we stimulated the superior parietal lobe (SPL using 5-Hz rTMS in 26 participants and recorded electroencephalography (EEG while they performed a delayed-recognition WM task. The analyses included the comparisons of event-related spectral perturbation (ERSP value variations in theta (4–7 Hz and alpha (8–14 Hz band frequencies between conditions (rTMS vs. sham, as well as the correlations between different brain areas. Following rTMS, the ERSP values of theta-band oscillations were significantly increased in the parietal and occipital-parietal brain areas (P < 0.05*, whereas the ERSP values of alpha-band oscillations were significantly decreased in the parietal area (P < 0.05*. The ERSP value variations of theta-band oscillations between the two conditions in the left parietal and left prefrontal areas were positively correlated with the response time (RT variations (by using rTMS, the more subject RT decreased, the more ERSP value of theta oscillation increased. The ERSP value variations of alpha-band oscillations in the left parietal and bilateral prefrontal areas were negatively correlated with RT variations (by using rTMS, the more RT of the subject decreased, the more ERSP value of alpha oscillation decreased. Inter-sites phase synchronization of theta-band EEG between the left parietal and left prefrontal areas, as well as alpha-band EEG between the left parietal and bilateral prefrontal areas were enhanced by rTMS. These results indicated that activities of both parietal and prefrontal areas were required for information storage, and these activities were related to the behavioral responses. Moreover, the connectivity

  18. 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 ...

  19. Asymmetric multisensory interactions of visual and somatosensory responses in a region of the rat parietal cortex.

    Directory of Open Access Journals (Sweden)

    Michael T Lippert

    Full Text Available Perception greatly benefits from integrating multiple sensory cues into a unified percept. To study the neural mechanisms of sensory integration, model systems are required that allow the simultaneous assessment of activity and the use of techniques to affect individual neural processes in behaving animals. While rodents qualify for these requirements, little is known about multisensory integration and areas involved for this purpose in the rodent. Using optical imaging combined with laminar electrophysiological recordings, the rat parietal cortex was identified as an area where visual and somatosensory inputs converge and interact. Our results reveal similar response patterns to visual and somatosensory stimuli at the level of current source density (CSD responses and multi-unit responses within a strip in parietal cortex. Surprisingly, a selective asymmetry was observed in multisensory interactions: when the somatosensory response preceded the visual response, supra-linear summation of CSD was observed, but the reverse stimulus order resulted in sub-linear effects in the CSD. This asymmetry was not present in multi-unit activity however, which showed consistently sub-linear interactions. These interactions were restricted to a specific temporal window, and pharmacological tests revealed significant local intra-cortical contributions to this phenomenon. Our results highlight the rodent parietal cortex as a system to model the neural underpinnings of multisensory processing in behaving animals and at the cellular level.

  20. Fronto-Parietal Network Reconfiguration Supports the Development of Reasoning Ability.

    Science.gov (United States)

    Wendelken, Carter; Ferrer, Emilio; Whitaker, Kirstie J; Bunge, Silvia A

    2016-05-01

    The goal of this fMRI study was to examine how well developmental improvements in reasoning ability can be explained by changes in functional connectivity between specific nodes in prefrontal and parietal cortices. To this end, we examined connectivity within the lateral fronto-parietal network (LFPN) and its relation to reasoning ability in 132 children and adolescents aged 6-18 years, 56 of whom were scanned twice over the course of 1.5 years. Developmental changes in strength of connections within the LFPN were most prominent in late childhood and early adolescence. Reasoning ability was related to functional connectivity between left rostrolateral prefrontal cortex (RLPFC) and inferior parietal lobule (IPL), but only among 12-18-year olds. For 9-11-year olds, reasoning ability was most strongly related to connectivity between left and right RLPFC; this relationship was mediated by working memory. For 6-8-year olds, significant relationships between connectivity and performance were not observed; in this group, processing speed was the primary mediator of improvement in reasoning ability. We conclude that different connections best support reasoning at different points in development and that RLPFC-IPL connectivity becomes an important predictor of reasoning during adolescence.

  1. Does a volume reduction of the parietal lobe contribute to freezing of gait in Parkinson's disease?

    Science.gov (United States)

    Rubino, Alfonso; Assogna, Francesca; Piras, Fabrizio; Di Battista, Maria Elena; Imperiale, Francesca; Chiapponi, Chiara; Spalletta, Gianfranco; Meco, Giuseppe

    2014-10-01

    Freezing of gait (FOG) is as a brief, episodic absence or marked reduction of forward progression of the feet despite the intention to walk. Structural neuroimaging studies on FOG in PD using volumetric techniques yielded variable and partially conflicting findings, probably reflecting the heterogeneity and complexity of the phenomenon. The aim of this study was to further explore the differences in local gray matter (GM) volume in patients with PD with and without FOG by using Voxel-Based Morphometry (VBM). We enrolled 26 patients (7 women and 19 men) with a diagnosis of PD in stable treatment with dopaminergic therapy. Thirteen patients classified as FOG+ were matched with thirteen non-freezer (FOG-) PD patients. All 26 participants underwent a detailed neuropsychological assessment as well as a VBM analysis derived from T1 weighted 3T MRI. The patient groups did not significantly differ for age, disease duration, H&Y stage, UPDRS part-III or educational attainment. No significant differences of cognitive profile emerged. PD-FOG+ patients showed a pattern of relative GM atrophy in left posterior parietal gyrus compared with PD-FOG-. Our results suggest that a specific pattern of cortical volume reduction involving posterior parietal cortex contributes to the occurrence of FOG in PD. These data agree with the growing body of evidence considering the parietal posterior cortex as an associative area involved in spatial control of motor behavior, par-taking in response selection to sensory evaluation. Copyright © 2014. Published by Elsevier Ltd.

  2. Late onset reversible cortical blindness following electrocution.

    Science.gov (United States)

    Chauhan, Bhumir; Philip, Vivek J; Shankar, Udaya C

    2015-12-01

    An elderly gentleman presented with acute onset of bilateral visual blurring and generalized headache after 1 week post electrocution injury. Clinically, the symptoms were attributed to cortical lesion. Magnetic resonance imaging (MRI) of brain revealed bilaterally symmetrical diffusion restriction in parietal and occipital areas. Treatment with intravenous steroids resulted in remarkable improvement in symptoms. Neurological injury secondary to electrocution is a well described entity having a variety of clinical presentation. We put forward our experience with this unique case presenting as post electrocution delayed onset of visual symptoms. Discussion and review of literature related to this clinical entity will also be presented.

  3. Dysfunction and dysconnection in cortical-striatal networks during sustained attention: Genetic risk for schizophrenia or bipolar disorder and its impact on brain network function

    Directory of Open Access Journals (Sweden)

    Vaibhav A. Diwadkar

    2014-05-01

    Full Text Available Abnormalities in the brain’s attention network may represent early identifiable neurobiological impairments in individuals at increased risk for schizophrenia or bipolar disorder. Here we provide evidence of dysfunctional regional and network function in adolescents at higher genetic risk for schizophrenia or bipolar disorder (henceforth HGR. During fMRI, participants engaged in a sustained attention task with variable demands. The task alternated between attention (120 s, visual control (passive viewing; 120 s and rest (20 s epochs. Low and high demand attention conditions were created using the rapid presentation of 2- or 3-digit numbers. Subjects were required to detect repeated presentation of numbers. We demonstrate that the recruitment of cortical and striatal regions are disordered in HGR: Relative to typical controls (TC, HGR showed lower recruitment of the dorsal prefrontal cortex, but higher recruitment of the superior parietal cortex. This imbalance was more dramatic in the basal ganglia. There, a group by task demand interaction was observed, such that increased attention demand led to increased engagement in TC, but disengagement in HGR. These activation studies were complemented by network analyses using Dynamic Causal Modeling. Competing model architectures were assessed across a network of cortical-striatal regions, distinguished at a second level using random effects Bayesian model selection. In the winning architecture, HGR were characterized by significant reductions in coupling across both frontal-striatal and frontal-parietal pathways. The effective connectivity analyses indicate emergent network dysconnection, consistent with findings in patients with schizophrenia. Emergent patterns of regional dysfunction and disconnection in cortical-striatal pathways may provide functional biological signatures in the adolescent risk state for psychiatric illness.

  4. The motor cortical representation of a muscle is not homogeneous in brain connectivity.

    Science.gov (United States)

    Smith, Jo Armour; Albishi, Alaa; Babikian, Sarine; Asavasopon, Skulpan; Fisher, Beth E; Kutch, Jason J

    2017-06-19

    Functional connectivity patterns of the motor cortical representational area of single muscles have not been extensively mapped in humans, particularly for the axial musculature. Functional connectivity may provide a neural substrate for adaptation of muscle activity in axial muscles that have both voluntary and postural functions. The purpose of this study was to combine brain stimulation and neuroimaging to both map the cortical representation of the external oblique (EO) in primary motor cortex (M1) and supplementary motor area (SMA), and to establish the resting-state functional connectivity associated with this representation. Motor-evoked potentials were elicited from the EO muscle in stimulation locations encompassing M1 and SMA. The coordinates of locations with the largest motor-evoked potentials were confirmed with task-based fMRI imaging during EO activation. The M1 and SMA components of the EO representation demonstrated significantly different resting-state functional connectivity with other brain regions: the SMA representation of the EO muscle was significantly more connected to the putamen and cerebellum, and the M1 representation of the EO muscle was significantly more connected to somatosensory cortex and the superior parietal lobule. This study confirms the representation of a human axial muscle in M1 and SMA, and demonstrates for the first time that different parts of the cortical representation of a human axial muscle have resting-state functional connectivity with distinct brain regions. Future studies can use the brain regions of interest we have identified here to test the association between resting-state functional connectivity and control of the axial muscles.

  5. Centrality of prefrontal and motor preparation cortices to Tourette Syndrome revealed by meta-analysis of task-based neuroimaging studies.

    Science.gov (United States)

    Polyanska, Liliana; Critchley, Hugo D; Rae, Charlotte L

    2017-01-01

    Tourette Syndrome (TS) is a neurodevelopmental condition characterized by chronic multiple tics, which are experienced as compulsive and 'unwilled'. Patients with TS can differ markedly in the frequency, severity, and bodily distribution of tics. Moreover, there are high comorbidity rates with attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), anxiety disorders, and depression. This complex clinical profile may account for apparent variability of findings across neuroimaging studies that connect neural function to cognitive and motor behavior in TS. Here we crystalized information from neuroimaging regarding the functional circuitry of TS, and furthermore, tested specifically for neural determinants of tic severity, by applying activation likelihood estimation (ALE) meta-analyses to neuroimaging (activation) studies of TS. Fourteen task-based studies (13 fMRI and one H2O-PET) met rigorous inclusion criteria. These studies, encompassing 25 experiments and 651 participants, tested for differences between TS participants and healthy controls across cognitive, motor, perceptual and somatosensory domains. Relative to controls, TS participants showed distributed differences in the activation of prefrontal (inferior, middle, and superior frontal gyri), anterior cingulate, and motor preparation cortices (lateral premotor cortex and supplementary motor area; SMA). Differences also extended into sensory (somatosensory cortex and the lingual gyrus; V4); and temporo-parietal association cortices (posterior superior temporal sulcus, supramarginal gyrus, and retrosplenial cortex). Within TS participants, tic severity (reported using the Yale Global Tic Severity Scale; YGTSS) selectively correlated with engagement of SMA, precentral gyrus, and middle frontal gyrus across tasks. The dispersed involvement of multiple cortical regions with differences in functional reactivity may account for heterogeneity in the symptomatic expression of TS and its

  6. Repetition suppression for speech processing in the associative occipital and parietal cortex of congenitally blind adults.

    Directory of Open Access Journals (Sweden)

    Laureline Arnaud

    Full Text Available In the congenitally blind (CB, sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI. We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth.

  7. Repetition Suppression for Speech Processing in the Associative Occipital and Parietal Cortex of Congenitally Blind Adults

    Science.gov (United States)

    Arnaud, Laureline; Sato, Marc; Ménard, Lucie; Gracco, Vincent L.

    2013-01-01

    In the congenitally blind (CB), sensory deprivation results in cross-modal plasticity, with visual cortical activity observed for various auditory tasks. This reorganization has been associated with enhanced auditory abilities and the recruitment of visual brain areas during sound and language processing. The questions we addressed are whether visual cortical activity might also be observed in CB during passive listening to auditory speech and whether cross-modal plasticity is associated with adaptive differences in neuronal populations compared to sighted individuals (SI). We focused on the neural substrate of vowel processing in CB and SI adults using a repetition suppression (RS) paradigm. RS has been associated with enhanced or accelerated neural processing efficiency and synchronous activity between interacting brain regions. We evaluated whether cortical areas in CB were sensitive to RS during repeated vowel processing and whether there were differences across the two groups. In accordance with previous studies, both groups displayed a RS effect in the posterior temporal cortex. In the blind, however, additional occipital, temporal and parietal cortical regions were associated with predictive processing of repeated vowel sounds. The findings suggest a more expanded role for cross-modal compensatory effects in blind persons during sound and speech processing and a functional transfer of specific adaptive properties across neural regions as a consequence of sensory deprivation at birth. PMID:23717628

  8. Rhythmic and melodic deviations in musical sequences recruit different cortical areas for mismatch detection.

    Science.gov (United States)

    Lappe, Claudia; Steinsträter, Olaf; Pantev, Christo

    2013-01-01

    The mismatch negativity (MMN), an event-related potential (ERP) representing the violation of an acoustic regularity, is considered as a pre-attentive change detection mechanism at the sensory level on the one hand and as a prediction error signal on the other hand, suggesting that bottom-up as well as top-down processes are involved in its generation. Rhythmic and melodic deviations within a musical sequence elicit a MMN in musically trained subjects, indicating that acquired musical expertise leads to better discrimination accuracy of musical material and better predictions about upcoming musical events. Expectation violations to musical material could therefore recruit neural generators that reflect top-down processes that are based on musical knowledge. We describe the neural generators of the musical MMN for rhythmic and melodic material after a short-term sensorimotor-auditory (SA) training. We compare the localization of musical MMN data from two previous MEG studies by applying beamformer analysis. One study focused on the melodic harmonic progression whereas the other study focused on rhythmic progression. The MMN to melodic deviations revealed significant right hemispheric neural activation in the superior temporal gyrus (STG), inferior frontal cortex (IFC), and the superior frontal (SFG) and orbitofrontal (OFG) gyri. IFC and SFG activation was also observed in the left hemisphere. In contrast, beamformer analysis of the data from the rhythm study revealed bilateral activation within the vicinity of auditory cortices and in the inferior parietal lobule (IPL), an area that has recently been implied in temporal processing. We conclude that different cortical networks are activated in the analysis of the temporal and the melodic content of musical material, and discuss these networks in the context of the dual-pathway model of auditory processing.

  9. Rhythmic and melodic deviations in musical sequences recruit different cortical areas for mismatch detection

    Directory of Open Access Journals (Sweden)

    Claudia eLappe

    2013-06-01

    Full Text Available The mismatch negativity (MMN, an event-related potential (ERP representing the violation of an acoustic regularity, is considered as a pre-attentive change detection mechanism at the sensory level on the one hand and as a prediction error signal on the other hand, suggesting that bottom-up as well as top-down processes are involved in its generation. Rhythmic and melodic deviations within a musical sequence elicit a mismatch negativity in musically trained subjects, indicating that acquired musical expertise leads to better discrimination accuracy of musical material and better predictions about upcoming musical events. Expectation violations to musical material could therefore recruit neural generators that reflect top-down processes that are based on musical knowledge.We describe the neural generators of the musical MMN for rhythmic and melodic material after a short-term sensorimotor-auditory training. We compare the localization of musical MMN data from two previous MEG studies by applying beamformer analysis. One study focused on the melodic harmonic progression whereas the other study focused on rhythmic progression. The MMN to melodic deviations revealed significant right hemispheric neural activation in the superior temporal gyrus (STG, inferior frontal cortex (IFC, and the superior frontal (SFG and orbitofrontal (OFG gyri. IFC and SFG activation was also observed in the left hemisphere. In contrast, beamformer analysis of the data from the rhythm study revealed bilatral activation within the vicinity of auditory cortices and in the inferior parietal lobule, an area that has recently been implied in temporal processing. We conclude that different cortical networks are activated in the analysis of the temporal and the melodic content of musical material, and discuss these networks in the context of the the dual-pathway model of auditory processing.

  10. White Matter Microstructure in Superior Longitudinal Fasciculus Associated with Spatial Working Memory Performance in Children

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Madsen, Kathrine Skak; Baaré, William F C

    2011-01-01

    memory (SWM) performance improves significantly throughout the childhood years, and several lines of evidence implicate the left fronto-parietal cortices and connecting fiber tracts in SWM processing. Here we report results from a study of 76 typically developing children, 7 to 13 years of age. We...

  11. Cathodal transcranial direct current stimulation of the posterior parietal cortex reduces steady-state postural stability during the effect of light touch.

    Science.gov (United States)

    Ishigaki, Tomoya; Imai, Ryota; Morioka, Shu

    2016-09-28

    Touching a stable object with a fingertip using slight force (mechanical support, which is referred to as the effect of light touch (LT). In the neural mechanism of the effect of LT, the specific contribution of the cortical brain activity toward the effect of LT remains undefined, particularly the contribution toward steady-state postural sway. The aim of the present study was to investigate the cortical region responsible for the reduction of postural sway in response to the effect of LT. Active LT was applied with the right fingertip and transcranial direct current stimulation (sham or cathodal) was applied to the left primary sensorimotor cortex or the left posterior parietal cortex in the two groups. The experiments were conducted using a single-blind sham-controlled crossover design. Steady-state postural sway was compared with the factors of transcranial direct current stimulation (sham or cathodal) and time (pre or post). In the results, the effect of LT reduced postural stability in the mediolateral direction after cathodal transcranial direct current stimulation of the left posterior parietal cortex. No effect was observed after stimulation of the left primary sensorimotor cortex. This indicates that the left posterior parietal cortex is partly responsible for the effect of LT when touching a fixed point with the right fingertip during suprapostural tasks, where posture is adjusted according to the precision requirements. Cortical processing of sensory integration for voluntary postural orientation in response to touch occurs in the posterior parietal cortex.

  12. The ‘when’ pathway of the right parietal lobe

    Science.gov (United States)

    Battelli, Lorella; Pascual-Leone, Alvaro; Cavanagh, Patrick

    2013-01-01

    The order of events, whether two events are seen as simultaneous or successive, sets the stage for the moment-to-moment interpretation of the visual world. Evidence from patients who have lesions to the parietal lobes and transcranial magnetic stimulation studies in normal subjects suggest that the right inferior parietal lobe underlies this analysis of event timing. Judgment of temporal order, simultaneity and high-level motion are all compromised following right parietal lesions and degraded after transcranial magnetic stimulation over the right parietal but not elsewhere. The results suggest that the right parietal lobe serves as part of a when pathway for both visual fields. We propose that the disruption of this mechanism is the underlying cause of a wide range of seemingly unrelated tasks being impaired in right parietal patients. PMID:17379569

  13. The right parietal lobe is critical for visual working memory.

    Science.gov (United States)

    Berryhill, Marian E; Olson, Ingrid R

    2008-01-01

    Visual working memory (VWM) permits the maintenance of object identities and their locations across brief delays such as those accompanying eye movements. Recent neuroimaging studies have emphasized the role of the posterior parietal lobe in this process although the specific nature of this involvement in VWM remains controversial. Neuroimaging findings suggest that the parietal lobe may have a general role in remembering various types of visual information whereas neuropsychological findings suggest that parietal involvement is primarily related to motor spatial attention and spatial memory. In the present study, patients with unilateral right parietal lobe damage, lacking symptoms of neglect, were tested in several VWM old/new recognition tasks. Parietal damage lead to impaired performance on all VWM tasks, including spatial, object, and object/spatial conjunction tasks. Deficits were found across several stimulus categories. These results provide neuropsychological support for neuroimaging results, and more generally indicate that the parietal lobe serves a general role in diverse forms of VWM.

  14. Is the parietal lobe necessary for recollection in humans?

    Science.gov (United States)

    Simons, Jon S; Peers, Polly V; Hwang, David Y; Ally, Brandon A; Fletcher, Paul C; Budson, Andrew E

    2008-03-07

    An intriguing puzzle in cognitive neuroscience over recent years has been the common observation of parietal lobe activation in functional neuroimaging studies during the performance of human memory tasks. These findings have surprised scientists and clinicians because they challenge decades of established thinking that the parietal lobe does not support memory function. However, direct empirical investigation of whether circumscribed parietal lobe lesions might indeed be associated with human memory impairment has been lacking. Here we confirm using functional magnetic resonance imaging that significant parietal lobe activation is observed in healthy volunteers during a task assessing recollection of the context in which events previously occurred. However, patients with parietal lobe lesions that overlap closely with the regions activated in the healthy volunteers nevertheless exhibit normal performance on the same recollection task. Thus, although the processes subserved by the human parietal lobe appear to be recruited to support memory function, they are not a necessary requirement for accurate remembering to occur.

  15. Visual Dysfunction in Posterior Cortical Atrophy

    Directory of Open Access Journals (Sweden)

    Mari N. Maia da Silva

    2017-08-01

    Full Text Available Posterior cortical atrophy (PCA is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions.

  16. Visual Dysfunction in Posterior Cortical Atrophy

    Science.gov (United States)

    da Silva, Mari N. Maia; Millington, Rebecca S.; Bridge, Holly; James-Galton, Merle; Plant, Gordon T.

    2017-01-01

    Posterior cortical atrophy (PCA) is a syndromic diagnosis. It is characterized by progressive impairment of higher (cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal, and posterior temporal lobes bilaterally. Most cases will prove to have Alzheimer pathology. The aim of this review is to summarize the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognized visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarized, with special attention to its role on the differential diagnosis with related conditions. PMID:28861031

  17. A focus on parietal cells as a renewing cell population

    Institute of Scientific and Technical Information of China (English)

    Sherif; M; Karam

    2010-01-01

    The fact that the acidsecreting parietal cells undergo continuous renewal has been ignored by many gastroenterologists and cell biologists. In the past, it was thought that these cells were static. However, by using 3Hthymidine radioautography in combination with electron microscopy, it was possible to demonstrate that parietal cells belong to a continuously renewing epithelial cell lineage. In the gastric glands, stem cells anchored in the isthmus region are responsible for the production of parietal cells...

  18. Sex Differences in Parietal Lobe Structure and Development

    OpenAIRE

    Salinas, Joel; Mills, Elizabeth D.; Conrad, Amy L.; Koscik, Timothy; Andreasen, Nancy C; Nopoulos, Peg

    2012-01-01

    Structural MRI studies provide evidence for sex differences in the human brain. Differences in surface area and the proportion of gray to white matter volume are observed, particularly in the parietal lobe. To our knowledge, there are no studies examining sex differences of parietal lobe structure in younger populations or in the context of development. The current study evaluated sex difference in the structure of the parietal lobe in children (7-17 years of age). Also, by adding the cohort ...

  19. The ‘when’ pathway of the right parietal lobe

    OpenAIRE

    Battelli, Lorella; Pascual-Leone, Alvaro; Cavanagh, Patrick

    2007-01-01

    The order of events, whether two events are seen as simultaneous or successive, sets the stage for the moment-to-moment interpretation of the visual world. Evidence from patients who have lesions to the parietal lobes and transcranial magnetic stimulation studies in normal subjects suggest that the right inferior parietal lobe underlies this analysis of event timing. Judgment of temporal order, simultaneity and high-level motion are all compromised following right parietal lesions and degrade...

  20. Callosal alien hand sign following a right parietal lobe infarction.

    Science.gov (United States)

    Kim, Young-Do; Lee, Eek-Sung; Lee, Kwang-Soo; Kim, Joong-Seok

    2010-06-01

    Callosal alien hand syndrome is characterized primarily by intermanual conflict and is associated with an anterior callosal lesion. We report a patient who presented with topographical disorientation and the callosal type alien hand sign. An MRI of the brain showed a right parietal lobe infarction. This is a rare example of callosal alien hand sign associated with a right parietal lesion. The right parietal lobe appeared to be responsible for the callosal hand sign in this patient, possibly due to interference with peristriate outflow pathways toward the parietal zones, where visual somatosensory interactions are likely to occur. Copyright 2009 Elsevier Ltd. All rights reserved.

  1. Alzheimer's disease: the downside of a highly evolved parietal lobe?

    Science.gov (United States)

    Bruner, Emiliano; Jacobs, Heidi I L

    2013-01-01

    Clinical grade Alzheimer's disease (AD) is only described in humans. Recent imaging studies in early AD patients showed that the parietal areas display the most prominent metabolic impairments. So far, neuroimaging studies have not been able to explain why the medial parietal regions possess this hub characteristic in AD. Paleoneurological and neuroanatomical studies suggest that our species, Homo sapiens, has a unique and derived organization of the parietal areas, which are involved in higher cognitive functions. Combining evidence from neuroimaging, paleontology, and comparative anatomy, we suggest that the vulnerability of the parietal lobe to neurodegenerative processes may be associated with the origin of our species. The species-specific parietal morphology in modern humans largely influenced the brain spatial organization, and it involved changes in vascularization and energy management, which may underlie the sensitivity of these areas to metabolic impairment. Metabolic constraints and anatomical evolutionary changes in the medial parietal regions of modern humans may be important in early AD onset. Taking into account the species-specific adaptations of the modern human parietal areas and their association with AD, we hypothesize that AD can be the evolutionary drawback of the specialized structure of our parietal lobes. The cognitive advantage is associated with increased sensitivity to neurodegenerative processes which, being limited to the post-reproductive period, have a minor effect on the overall genetic fitness. The changes of energy requirements associated with form and size variations at the parietal areas may support the hypothesis of AD as a metabolic syndrome.

  2. Is the posterior parietal lobe involved in working memory retrieval? Evidence from patients with bilateral parietal lobe damage.

    Science.gov (United States)

    Berryhill, Marian E; Olson, Ingrid R

    2008-01-01

    Neuroimaging evidence suggests that the parietal lobe has an important role in memory retrieval, yet neuropsychology is largely silent on this topic. Recently, we reported that unilateral parietal lobe damage impairs various forms of visual working memory when tested by old/new recognition. Here, we investigate whether parietal lobe working memory deficits are linked to problems at retrieval. We tested two patients with bilateral parietal lobe damage in a series of visual working memory tasks that probed recall and old/new recognition. Stimuli were presented sequentially and several stimulus categories were tested. The results of these experiments show that parietal lobe damage disproportionately impairs old/new recognition as compared to cued recall across stimulus categories. The observed performance dissociation suggests that the posterior parietal lobe plays a particularly vital role in working memory retrieval.

  3. Abstract categories of functions in anterior parietal lobe.

    Science.gov (United States)

    Leshinskaya, Anna; Caramazza, Alfonso

    2015-09-01

    Knowledge of function is critical for selecting objects to meet action goals, even when the affordances of those objects are not mechanical-for instance, both a painting and a vase can decorate a room. To identify neural representations of such abstract function concepts, we asked participants in an fMRI scanner to view a variety of objects and evaluate their utility to each of four goals (two Decoration goals: dress up for a night out and decorate a house, and two Protection goals: protect your body from the cold and keep objects dry in a flooded basement). These task conditions differed in the kind of functional evaluation participants had to perform over objects, but did not vary in the objects themselves. We performed a searchlight multivariate pattern analysis to identify cortical representations in which neural patterns were more similar for the pairs of similar-goal than dissimilar-goal task conditions (Decorate vs. Protect). We report such effects in anterior inferior parietal lobe (aIPL) close to regions typically reported for processing tool-related actions, and thought to be important for representing how they are manipulated. However, the current study design fully controlled for manipulation similarity, which predicted orthogonal relationships among the conditions. We conclude that the aIPL likely has nearby, but distinct, representations of both manipulation and function knowledge, and thereby may have a broader role in understanding how objects can be used, representing not just physical affordances but also abstract functional criteria such as esthetic value or purpose categories such as decorate. This pattern of localization has implications for how semantic knowledge is organized in the brain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Muscarinic responses of gastric parietal cells

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, J.M.; Kajimura, M.; Scott, D.R.; Hersey, S.J.; Sachs, G. (Department of Medicine, University of California, Los Angeles (United States))

    1991-06-01

    Isolated rabbit gastric glands were used to study the nature of the muscarinic cholinergic responses of parietal cells. Carbachol stimulation of acid secretion, as measured by the accumulation of aminopyrine, was inhibited by the M1 antagonist, pirenzepine, with an IC50 of 13 microM; by the M2 antagonist, 11,2-(diethylamino)methyl-1 piperidinyl acetyl-5,11-dihydro-6H-pyrido 2,3-b 1,4 benzodiazepin-6-one (AF-DX 116), with an IC50 of 110 microM; and by the M1/M3 antagonist, diphenyl-acetoxy-4-methylpiperidinemethiodide, with an IC50 of 35 nM. The three antagonists displayed equivalent IC50 values for the inhibition of carbachol-stimulated production of 14CO2 from radiolabeled glucose, which is a measure of the turnover of the H,K-ATPase, the final step of acid secretion. Intracellular calcium levels were measured in gastric glands loaded with FURA 2. Carbachol was shown to both release calcium from an intracellular pool and to promote calcium entry across the plasma membrane. The calcium entry was inhibitable by 20 microM La3+. The relative potency of the three muscarinic antagonists for inhibition of calcium entry was essentially the same as for inhibition of acid secretion or pump related glucose oxidation. Image analysis of the glands showed the effects of carbachol, and of the antagonists, on intracellular calcium were occurring largely in the parietal cell. The rise in cell calcium due to release of calcium from intracellular stores was inhibited by 4-DAMP with an IC50 of 1.7 nM, suggesting that the release pathway was regulated by a low affinity M3 muscarinic receptor or state; Ca entry and acid secretion are regulated by a high affinity M3 muscarinic receptor or state, inhibited by higher 4-DAMP concentrations, suggesting that it is the steady-state elevation of Ca that is related to parietal cell function rather than the (Ca)i transient.

  5. 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.

  6. Distinct Genetic Influences on Cortical and Subcortical Brain Structures

    Science.gov (United States)

    Wen, Wei; Thalamuthu, Anbupalam; Mather, Karen A.; Zhu, Wanlin; Jiang, Jiyang; de Micheaux, Pierre Lafaye; Wright, Margaret J.; Ames, David; Sachdev, Perminder S.

    2016-09-01

    This study examined the heritability of brain grey matter structures in a subsample of older adult twins (93 MZ and 68 DZ twin pairs; mean age 70 years) from the Older Australian Twins Study. The heritability estimates of subcortical regions ranged from 0.41 (amygdala) to 0.73 (hippocampus), and of cortical regions, from 0.55 (parietal lobe) to 0.78 (frontal lobe). Corresponding structures in the two hemispheres were influenced by the same genetic factors and high genetic correlations were observed between the two hemispheric regions. There were three genetically correlated clusters, comprising (i) the cortical lobes (frontal, temporal, parietal and occipital lobes); (ii) the basal ganglia (caudate, putamen and pallidum) with weak genetic correlations with cortical lobes, and (iii) the amygdala, hippocampus, thalamus and nucleus accumbens grouped together, which genetically correlated with both basal ganglia and cortical lobes, albeit relatively weakly. Our study demonstrates a complex but patterned and clustered genetic architecture of the human brain, with divergent genetic determinants of cortical and subcortical structures, in particular the basal ganglia.

  7. Longitudinal development of frontoparietal activity during feedback learning: Contributions of age, performance, working memory and cortical thickness

    Directory of Open Access Journals (Sweden)

    Sabine Peters

    2016-06-01

    Full Text Available Feedback learning is a crucial skill for cognitive flexibility that continues to develop into adolescence, and is linked to neural activity within a frontoparietal network. Although it is well conceptualized that activity in the frontoparietal network changes during development, there is surprisingly little consensus about the direction of change. Using a longitudinal design (N = 208, 8–27 years, two measurements in two years, we investigated developmental trajectories in frontoparietal activity during feedback learning. Our first aim was to test for linear and nonlinear developmental trajectories in dorsolateral prefrontal cortex (DLPFC, superior parietal cortex (SPC, supplementary motor area (SMA and anterior cingulate cortex (ACC. Second, we tested which factors (task performance, working memory, cortical thickness explained additional variance in time-related changes in activity besides age. Developmental patterns for activity in DLPFC and SPC were best characterized by a quadratic age function leveling off/peaking in late adolescence. There was a linear increase in SMA and a linear decrease with age in ACC activity. In addition to age, task performance explained variance in DLPFC and SPC activity, whereas cortical thickness explained variance in SMA activity. Together, these findings provide a novel perspective of linear and nonlinear developmental changes in the frontoparietal network during feedback learning.

  8. Automatic and intentional number processing both rely on intact right parietal cortex: A combined fMRI and neuronavigated TMS study.

    Directory of Open Access Journals (Sweden)

    Roi eCohen Kadosh

    2012-02-01

    Full Text Available Practice and training usually lead to performance increase in a given task. In addition, a shift from intentional towards more automatic processing mechanisms is often observed. It is currently debated whether automatic and intentional processing is subserved by the same or by different mechanism(s, and whether the same or different regions in the brain are recruited. Previous correlational evidence provided by behavioural, neuroimaging, modelling, and neuropsychological studies addressing this question yielded conflicting results. Here we used transcranial magnetic stimulation (TMS to compare the causal influence of disrupting either left or right parietal cortex during automatic and intentional numerical processing, as reflected by the size congruity effect and the numerical distance effect, respectively. We found a functional hemispheric asymmetry within parietal cortex with only the TMS-induced right parietal disruption impairing both automatic and intentional numerical processing. In contrast, disrupting the left parietal lobe with TMS, or applying sham stimulation, did not affect performance during automatic or intentional numerical processing. The current results provide causal evidence for the functional relevance of right, but not left, parietal cortex for intentional and automatic numerical processing, implying that at least within the parietal cortices, automatic and intentional numerical processing rely on the same underlying hemispheric lateralization.

  9. Increased BOLD variability in the parietal cortex and enhanced parieto-occipital connectivity during tactile perception in congenitally blind individuals.

    Science.gov (United States)

    Leo, Andrea; Bernardi, Giulio; Handjaras, Giacomo; Bonino, Daniela; Ricciardi, Emiliano; Pietrini, Pietro

    2012-01-01

    Previous studies in early blind individuals posited a possible role of parieto-occipital connections in conveying nonvisual information to the visual occipital cortex. As a consequence of blindness, parietal areas would thus become able to integrate a greater amount of multimodal information than in sighted individuals. To verify this hypothesis, we compared fMRI-measured BOLD signal temporal variability, an index of efficiency in functional information integration, in congenitally blind and sighted individuals during tactile spatial discrimination and motion perception tasks. In both tasks, the BOLD variability analysis revealed many cortical regions with a significantly greater variability in the blind as compared to sighted individuals, with an overlapping cluster located in the left inferior parietal/anterior intraparietal cortex. A functional connectivity analysis using this region as seed showed stronger correlations in both tasks with occipital areas in the blind as compared to sighted individuals. As BOLD variability reflects neural integration and processing efficiency, these cross-modal plastic changes in the parietal cortex, even if described in a limited sample, reinforce the hypothesis that this region may play an important role in processing nonvisual information in blind subjects and act as a hub in the cortico-cortical pathway from somatosensory cortex to the reorganized occipital areas.

  10. Increased BOLD Variability in the Parietal Cortex and Enhanced Parieto-Occipital Connectivity during Tactile Perception in Congenitally Blind Individuals

    Directory of Open Access Journals (Sweden)

    Andrea Leo

    2012-01-01

    Full Text Available Previous studies in early blind individuals posited a possible role of parieto-occipital connections in conveying nonvisual information to the visual occipital cortex. As a consequence of blindness, parietal areas would thus become able to integrate a greater amount of multimodal information than in sighted individuals. To verify this hypothesis, we compared fMRI-measured BOLD signal temporal variability, an index of efficiency in functional information integration, in congenitally blind and sighted individuals during tactile spatial discrimination and motion perception tasks. In both tasks, the BOLD variability analysis revealed many cortical regions with a significantly greater variability in the blind as compared to sighted individuals, with an overlapping cluster located in the left inferior parietal/anterior intraparietal cortex. A functional connectivity analysis using this region as seed showed stronger correlations in both tasks with occipital areas in the blind as compared to sighted individuals. As BOLD variability reflects neural integration and processing efficiency, these cross-modal plastic changes in the parietal cortex, even if described in a limited sample, reinforce the hypothesis that this region may play an important role in processing nonvisual information in blind subjects and act as a hub in the cortico-cortical pathway from somatosensory cortex to the reorganized occipital areas.

  11. Larger right posterior parietal volume in action video game experts: a behavioral and voxel-based morphometry (VBM) study.

    Science.gov (United States)

    Tanaka, Satoshi; Ikeda, Hanako; Kasahara, Kazumi; Kato, Ryo; Tsubomi, Hiroyuki; Sugawara, Sho K; Mori, Makoto; Hanakawa, Takashi; Sadato, Norihiro; Honda, Manabu; Watanabe, Katsumi

    2013-01-01

    Recent studies suggest that action video game players exhibit superior performance in visuospatial cognitive tasks compared with non-game players. However, the neural basis underlying this visuospatial cognitive performance advantage remains largely unknown. The present human behavioral and imaging study compared gray matter volume in action video game experts and non-experts using structural magnetic resonance imaging and voxel-based morphometry analysis. The results revealed significantly larger gray matter volume in the right posterior parietal cortex in experts compared with non-experts. Furthermore, the larger gray matter volume in the right posterior parietal cortex significantly correlated with individual performance in a visual working memory task in experts. These results suggest that differences in brain structure may be linked to extensive video game play, leading to superior visuospatial cognitive performance in action video game experts.

  12. Activation in the Right Inferior Parietal Lobule Reflects the Representation of Musical Structure beyond Simple Pitch Discrimination

    Science.gov (United States)

    Royal, Isabelle; Vuvan, Dominique T.; Zendel, Benjamin Rich; Robitaille, Nicolas; Schönwiesner, Marc; Peretz, Isabelle

    2016-01-01

    Pitch discrimination tasks typically engage the superior temporal gyrus and the right inferior frontal gyrus. It is currently unclear whether these regions are equally involved in the processing of incongruous notes in melodies, which requires the representation of musical structure (tonality) in addition to pitch discrimination. To this aim, 14 participants completed two tasks while undergoing functional magnetic resonance imaging, one in which they had to identify a pitch change in a series of non-melodic repeating tones and a second in which they had to identify an incongruous note in a tonal melody. In both tasks, the deviants activated the right superior temporal gyrus. A contrast between deviants in the melodic task and deviants in the non-melodic task (melodic > non-melodic) revealed additional activity in the right inferior parietal lobule. Activation in the inferior parietal lobule likely represents processes related to the maintenance of tonal pitch structure in working memory during pitch discrimination. PMID:27195523

  13. Cortical Thickness Changes Associated with Photoparoxysmal Response

    DEFF Research Database (Denmark)

    Hanganu, Alexandru; Groppa, Stanislav A; Deuschl, Günther

    2014-01-01

    Photoparoxysmal response (PPR) is an EEG trait of spike and spike-wave discharges in response to photic stimulation that is closely linked to idiopathic generalized epilepsy (IGE). In our previous studies we showed that PPR is associated with functional alterations in the occipital and frontal co......) and compared these groups with a group of PPR-negative-healthy-controls (HC, n = 17; 15.3 ± 3.6 years; 6 males). Our results revealed an increase of cortical thickness in the occipital, frontal and parietal cortices bilaterally in PPR-positive-subjects in comparison to HC. Moreover PPR......-positive-subjects presented a significant decrease of cortical thickness in the temporal cortex in the same group contrast. IGE patients exhibited lower cortical thickness in the temporal lobe bilaterally and in the right paracentral region in comparison to PPR-positive-subjects. Our study demonstrates structural changes...... in the occipital lobe, frontoparietal regions and temporal lobe, which also show functional changes associated with PPR. Patients with epilepsy present changes in the temporal lobe and supplementary motor area....

  14. The superior transvelar approach to the fourth ventricle and brainstem.

    Science.gov (United States)

    Ezer, Haim; Banerjee, Anirban Deep; Bollam, Papireddy; Guthikonda, Bharat; Nanda, Anil

    2012-06-01

    Objective The superior transvelar approach is used to access pathologies located in the fourth ventricle and brainstem. The surgical path is below the venous structures, through the superior medullary velum. Following splitting the tentorial edge, near the tentorial apex, the superior medullary velum is split in the cerebello-mesencephalic fissure. Using the supracerebellar infratentorial, transtentorial or parietal interhemispheric routes, the superior medullary velum is approached. Splitting this velum provides a detailed view of the fourth ventricle and its floor. Materials and Methods A total of 10 formalin-fixed specimens were dissected in a stepwise manner to simulate the superior transvelar approach to the fourth ventricle. The exposure gained the distance from the craniotomy site and the ease of access was assessed for each of the routes. We also present an illustrative case, operated by the senior author (AN). Results The superior transvelar approach provides access to the entire length of the fourth ventricle floor, from the aqueduct to the obex, when using the parietal interhemispheric route. In addition, this approach provides access to the entire width of the floor of the fourth ventricle; however, this requires retracting the superior cerebellar peduncle. Using the supracerebellar infratentorial route gives a limited exposure of the superior part of the fourth ventricle. The occipital interhemispheric route is a compromise between these two. Conclusion The superior transvelar approach to the fourth ventricle provides a route for approaching the fourth ventricle from above. This approach does not require opening the posterior fossa in the traditional way, and provides a reasonable alternative for accessing the superior fourth ventricle.

  15. Bilateral fronto-parietal integrity in young chronic cigarette smokers: a diffusion tensor imaging study.

    Directory of Open Access Journals (Sweden)

    Yanhui Liao

    Full Text Available BACKGROUND: Cigarette smoking continues to be the leading cause of preventable morbidity and mortality in China and other countries. Previous studies have demonstrated gray matter loss in chronic smokers. However, only a few studies assessed the changes of white matter integrity in this group. Based on those previous reports of alterations in white matter integrity in smokers, the aim of this study was to examine the alteration of white matter integrity in a large, well-matched sample of chronic smokers and non-smokers. METHODOLOGY/PRINCIPAL FINDINGS: Using in vivo diffusion tensor imaging (DTI to measure the differences of whole-brain white matter integrity between 44 chronic smoking subjects (mean age, 28.0±5.6 years and 44 healthy age- and sex-matched comparison non-smoking volunteers (mean age, 26.3±5.8 years. DTI was performed on a 3-Tesla Siemens scanner (Allegra; Siemens Medical System. The data revealed that smokers had higher fractional anisotropy (FA than healthy non-smokers in almost symmetrically bilateral fronto-parietal tracts consisting of a major white matter pathway, the superior longitudinal fasciculus (SLF. CONCLUSION/SIGNIFICANCE: We found the almost symmetrically bilateral fronto-parietal whiter matter changes in a relatively large sample of chronic smokers. These findings support the hypothesis that chronic cigarette smoking involves alterations of bilateral fronto-parietal connectivity.

  16. Tool-use practice induces changes in intrinsic functional connectivity of parietal areas

    Directory of Open Access Journals (Sweden)

    Kwangsun eYoo

    2013-02-01

    Full Text Available Intrinsic functional connectivity from resting state functional magnetic resonance imaging (rsfMRI has increasingly received attention as a possible predictor of cognitive function and performance. In this study, we investigated the influence of practicing skillful tool manipulation on intrinsic functional connectivity in the resting brain. Acquisition of tool-use skill has two aspects such as formation of motor representation for skillful manipulation and acquisition of the tool concept. To dissociate these two processes, we chose chopsticks-handling with the non-dominant hand. Because participants were already adept at chopsticks-handling with their dominant hand, practice with the non-dominant hand involved only acquiring the skill for tool manipulation with existing knowledge. Eight young participants practiced chopsticks-handling with their non-dominant hand for 8 weeks. They underwent fMRI sessions before and after the practice. As a result, functional connectivity among tool-use-related regions of the brain decreased after practice. We found decreased functional connectivity centered on parietal areas, mainly the supramarginal gyrus and superior parietal lobule and additionally between the primary sensorimotor area and cerebellum. These results suggest that the parietal lobe and cerebellum purely mediate motor learning for skillful tool-use. This decreased functional connectivity may represent increased efficiency of functional network.

  17. The Role of Human Parietal Cortex in Attention Networks

    Science.gov (United States)

    Han, Shihui; Jiang, Yi; Gu, Hua; Rao, Hengyi; Mao, Lihua; Cui, Yong; Zhai, Renyou

    2004-01-01

    The parietal cortex has been proposed as part of the neural network for guiding spatial attention. However, it is unclear to what degree the parietal cortex contributes to the attentional modulations of activities of the visual cortex and the engagement of the frontal cortex in the attention network. We recorded behavioural performance and…

  18. Use of explicit memory cues following parietal lobe lesions.

    Science.gov (United States)

    Dobbins, Ian G; Jaeger, Antonio; Studer, Bettina; Simons, Jon S

    2012-11-01

    The putative role of the lateral parietal lobe in episodic memory has recently become a topic of considerable debate, owing primarily to its consistent activation for studied materials during functional magnetic resonance imaging studies of recognition. Here we examined the performance of patients with parietal lobe lesions using an explicit memory cueing task in which probabilistic cues ("Likely Old" or "Likely New"; 75% validity) preceded the majority of verbal recognition memory probes. Without cues, patients and control participants did not differ in accuracy. However, group differences emerged during the "Likely New" cue condition with controls responding more accurately than parietal patients when these cues were valid (preceding new materials) and trending towards less accuracy when these cues were invalid (preceding old materials). Both effects suggest insufficient integration of external cues into memory judgments on the part of the parietal patients whose cued performance largely resembled performance in the complete absence of cues. Comparison of the parietal patients to a patient group with frontal lobe lesions suggested the pattern was specific to parietal and adjacent area lesions. Overall, the data indicate that parietal lobe patients fail to appropriately incorporate external cues of novelty into recognition attributions. This finding supports a role for the lateral parietal lobe in the adaptive biasing of memory judgments through the integration of external cues and internal memory evidence. We outline the importance of such adaptive biasing through consideration of basic signal detection predictions regarding maximum possible accuracy with and without informative environmental cues. Copyright © 2012 Elsevier Ltd. All rights reserved.

  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. Parietal lobe epilepsy: the great imitator among focal epilepsies.

    Science.gov (United States)

    Ristić, Aleksandar J; Alexopoulos, Andreas V; So, Norman; Wong, Chong; Najm, Imad M

    2012-03-01

    Comprising large areas of association cortex, the parietal lobe is part of an extensive synaptic network elaborately intertwined with other brain regions. We hypothesize that such widespread projections are responsible for producing inaccurate localisation readings on scalp EEG and clinical semiology in patients with parietal lobe epilepsies, as opposed to frontal or temporal lobe epilepsies. Our study included 50 patients with pharmacoresistant focal epilepsy, who were subsequently rendered seizure-free for ≥12 months (median: 23 months) following resections limited to the frontal (n=17), temporal (n=17), or parietal (n=16) lobes. Interictal and ictal EEG data with accompanying seizure video recordings were extracted from archived files of scalp video-EEG monitoring. Two blinded raters independently reviewed the EEG according to predetermined criteria. Videos of seizures were then observed, as raters formulated their final electroclinical impression (ECI), identifying patients' abnormal neuronal activities with parietal, temporal, and frontal lobe epilepsy, or unspecified localisation. Groups did not differ significantly in demographics, age at epilepsy onset, or presence of MRI abnormalities. Interictal discharges in parietal lobe epilepsy showed the greatest magnitude of scatter outside the lobe of origin; the majority of patients with parietal lobe epilepsy had more than one spike population (pparietal lobe epilepsy cases (p=0.024). Whenever raters confidently limited their ECI to one lobar subtype, overall accuracy was excellent. Lobar classifications by ECI were highly accurate for temporal lobe epilepsy, vacillating in frontal lobe epilepsy, and least accurate in parietal lobe epilepsy subjects. Scalp EEG readings of parietal lobe epilepsy patients showed a more variable scatter of interictal discharges and a lower localisation value of ictal recordings compared to temporal and frontal lobe epilepsy subjects, suggesting an increased likelihood of

  1. Individual structural differences in left inferior parietal area are associated with schoolchildrens’ arithmetic scores

    Directory of Open Access Journals (Sweden)

    Yongxin eLi

    2013-12-01

    Full Text Available Arithmetic skill is of critical importance for academic achievement, professional success and everyday life, and childhood is the key period to acquire this skill. Neuroimaging studies have identified that left parietal regions are a key neural substrate for representing arithmetic skill. Although the relationship between functional brain activity in left parietal regions and arithmetic skill has been studied in detail, it remains unclear about the relationship between arithmetic achievement and structural properties in left inferior parietal area in schoolchildren. The current study employed a combination of voxel-based morphometry (VBM for high-resolution T1-weighted images and fiber tracking on diffusion tensor imaging (DTI to examine the relationship between structural properties in the inferior parietal area and arithmetic achievement in 10-year-old schoolchildren. VBM of the T1-weighted images revealed that individual differences in arithmetic scores were significantly and positively correlated with the grey matter (GM volume in the left intraparietal sulcus (IPS. Fiber tracking analysis revealed that the forceps major, left superior longitudinal fasciculus (SLF, bilateral inferior longitudinal fasciculus (ILF and inferior fronto-occipital fasciculus (IFOF were the primary pathways connecting the left IPS with other brain areas. Furthermore, the regression analysis of the probabilistic pathways revealed a significant and positive correlation between the fractional anisotropy (FA values in the left SLF, ILF and bilateral IFOF and arithmetic scores. The brain structure-behavior correlation analyses indicated that the GM volumes in the left IPS and the FA values in the tract pathways connecting left IPS were both related to children’s arithmetic achievement. The present findings provide evidence that individual structural differences in the left IPS are associated with arithmetic scores in schoolchildren.

  2. Variability in the distribution of callosal projection neurons in the adult rat parietal cortex.

    Science.gov (United States)

    Ivy, G O; Gould, H J; Killackey, H P

    1984-07-23

    Previous reports have shown that the barrel field area of the parietal cortex of the adult rat contains relatively few callosal projection neurons, even though callosal projection neurons are abundant in this cortical region in the neonatal rat. Furthermore, it has been shown that many of the callosal neurons which seem to disappear as the animal matures do not die, but project to ipsilateral cortical areas. These findings rely on the ability of retrograde transport techniques which utilize injections of horseradish peroxidase (HRP) or of fluorescent dyes into one hemisphere. We now show that several technical modifications of the HRP technique yield a wider distribution of HRP-containing neurons in the contralateral barrel field area of the adult rat than previously reported. These include implants of HRP pellets into transected axons of the corpus callosum, the addition of DMSO and nonidet P40 to Sigma VI HRP, wheat germ agglutinin HRP and the use of tetramethyl benzidine as the chromogen in the reaction procedure. Our findings have implications for transport studies in general and for the development of the cortical barrel field in particular.

  3. Caracterización del injerto parietal

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    José Manuel Díaz Fernández

    1996-12-01

    Full Text Available Se realizó un estudio descriptivo, longitudinal y prospectivo de 22 pacientes en los que se utilizó el injerto parietal autógeno para reconstruir defectos del cráneo, en los servicios de Cirugía Maxilofacial y Neurocirugía del Hospital Clinicoquirúrgico Docente "Saturnino Lora", de Santiago de Cuba, desde 1988 hasta 1991. El método de extracción del injerto con división in situ resultó el más empleado y el que ofreció las mejores posibilidades de reconstrucción en cuanto a forma, volumen y flexibilidad, por lo que se recomienda en los defectos pequeños y medianos, sobre todo de la región frontal y áreas adyacentes, donde el contorno y la simetría son los 2 aspectos fundamentales que se deben conseguir. El método de división, in vitro se utilizó en las reconstrucciones de las deformidades de grandes dimensiones, particularmente en aquellas que no incluían la frente. El índice de complicaciones fue bajoIt was carried out a descriptive, longitudinal and prospective study of 22 patients in whom an autogenous parietal graft was used to reconstruct cranial defects at the Maxillofacial Surgery and Neurosurgery Department of the "Saturnino Lora" Clinical and Surgical Teaching Hospital, in Santiago de Cuba, from 1988 to 1991. The graft extraction method with division in situ was the most used and offered the best possibilities for reconstruction as regards form, volume and flexibility. Therefore, it is recommended for small and medium defects, particularly of the frontal region and adjacent areas, where contour and symmetry are the two fundamental aspects to be taken into consideration. The method of division in vitro was used to reconstruct large deformities, specially those in which the forehead was not included. The complications index was low

  4. Neuro-cognitive mechanisms of simultanagnosia in patients with posterior cortical atrophy.

    Science.gov (United States)

    Neitzel, Julia; Ortner, Marion; Haupt, Marleen; Redel, Petra; Grimmer, Timo; Yakushev, Igor; Drzezga, Alexander; Bublak, Peter; Preul, Christoph; Sorg, Christian; Finke, Kathrin

    2016-12-01

    deficits of simultaneous perception. Compared to controls, we observed a specific slowing of visual processing speed, while visual short-term memory capacity was preserved. In a regression analysis, processing speed was identified as the only significant predictor of simultaneous perception deficits that explained a high degree of variance (70-82%) across simultanagnosia tasks. More severe slowing was also indicative for more severe impairments in reading and scene comprehension. Voxel-based morphometry yielded extensive reductions of grey and white matter in parieto-occipital and thalamic brain areas. Importantly, the degree of individual atrophy of white matter in left superior parietal lobe, but not of any grey matter region, was associated with processing speed. Based on these findings, we propose that atrophy of white matter commonly observed in posterior cortical atrophy leads to slowing of visual processing speed, which underlies the overt clinical symptoms of simultanagnosia. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study.

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    Qiu, Wei-Hong; Wu, Hui-Xiang; Yang, Qing-Lu; Kang, Zhuang; Chen, Zhao-Cong; Li, Kui; Qiu, Guo-Rong; Xie, Chun-Qing; Wan, Gui-Fang; Chen, Shao-Qiong

    2017-01-01

    Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas.

  6. Evidence of cortical reorganization of language networks after stroke with subacute Broca's aphasia: a blood oxygenation level dependent-functional magnetic resonance imaging study

    Science.gov (United States)

    Qiu, Wei-hong; Wu, Hui-xiang; Yang, Qing-lu; Kang, Zhuang; Chen, Zhao-cong; Li, Kui; Qiu, Guo-rong; Xie, Chun-qing; Wan, Gui-fang; Chen, Shao-qiong

    2017-01-01

    Aphasia is an acquired language disorder that is a common consequence of stroke. The pathogenesis of the disease is not fully understood, and as a result, current treatment options are not satisfactory. Here, we used blood oxygenation level-dependent functional magnetic resonance imaging to evaluate the activation of bilateral cortices in patients with Broca's aphasia 1 to 3 months after stroke. Our results showed that language expression was associated with multiple brain regions in which the right hemisphere participated in the generation of language. The activation areas in the left hemisphere of aphasia patients were significantly smaller compared with those in healthy adults. The activation frequency, volumes, and intensity in the regions related to language, such as the left inferior frontal gyrus (Broca's area), the left superior temporal gyrus, and the right inferior frontal gyrus (the mirror region of Broca's area), were lower in patients compared with healthy adults. In contrast, activation in the right superior temporal gyrus, the bilateral superior parietal lobule, and the left inferior temporal gyrus was stronger in patients compared with healthy controls. These results suggest that the right inferior frontal gyrus plays a role in the recovery of language function in the subacute stage of stroke-related aphasia by increasing the engagement of related brain areas. PMID:28250756

  7. Navigating actions through the rodent parietal cortex

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    Jonathan R. Whitlock

    2014-05-01

    Full Text Available The posterior parietal cortex (PPC participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial versus motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 second in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys.

  8. Abnormal parietal function in conversion paresis.

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    Marije van Beilen

    Full Text Available The etiology of medically unexplained symptoms such as conversion disorder is poorly understood. This is partly because the interpretation of neuroimaging results in conversion paresis has been complicated by the use of different control groups, tasks and statistical comparisons. The present study includes these different aspects in a single data set. In our study we included both normal controls and feigners to control for conversion paresis. We studied both movement execution and imagery, and we contrasted both within-group and between-group activation. Moreover, to reveal hemisphere-specific effects that have not been reported before, we performed these analyses using both flipped and unflipped data. This approach resulted in the identification of abnormal parietal activation which was specific for conversion paresis patients. Patients also showed reduced activity in the prefrontal cortex, supramarginal gyrus and precuneus, including hemisphere-specific activation that is lateralized in the same hemisphere, regardless of right- or left-sided paresis. We propose that these regions are candidates for an interface between psychological mechanisms and disturbed higher-order motor control. Our study presents an integrative neurophysiological view of the mechanisms that contribute to the etiology of this puzzling psychological disorder, which can be further investigated with other types of conversion symptoms.

  9. Abnormal Parietal Function in Conversion Paresis

    Science.gov (United States)

    van Beilen, Marije; de Jong, Bauke M.; Gieteling, Esther W.; Renken, Remco; Leenders, Klaus L.

    2011-01-01

    The etiology of medically unexplained symptoms such as conversion disorder is poorly understood. This is partly because the interpretation of neuroimaging results in conversion paresis has been complicated by the use of different control groups, tasks and statistical comparisons. The present study includes these different aspects in a single data set. In our study we included both normal controls and feigners to control for conversion paresis. We studied both movement execution and imagery, and we contrasted both within-group and between-group activation. Moreover, to reveal hemisphere-specific effects that have not been reported before, we performed these analyses using both flipped and unflipped data. This approach resulted in the identification of abnormal parietal activation which was specific for conversion paresis patients. Patients also showed reduced activity in the prefrontal cortex, supramarginal gyrus and precuneus, including hemisphere-specific activation that is lateralized in the same hemisphere, regardless of right- or left-sided paresis. We propose that these regions are candidates for an interface between psychological mechanisms and disturbed higher-order motor control. Our study presents an integrative neurophysiological view of the mechanisms that contribute to the etiology of this puzzling psychological disorder, which can be further investigated with other types of conversion symptoms. PMID:22039428

  10. The role of the right parietal lobe in anorexia nervosa.

    Science.gov (United States)

    Nico, D; Daprati, E; Nighoghossian, N; Carrier, E; Duhamel, J-R; Sirigu, A

    2010-09-01

    Patients with anorexia nervosa (AN) overestimate their size despite being severely underweight. Whether this misperception echoes an underlying emotional disturbance or also reflects a genuine body-representation deficit is debatable. Current measures inquire directly about subjective perception of body image, thus distinguishing poorly between top-down effects of emotions/attitudes towards the body and disturbances due to proprioceptive disorders/distorted body schema. Disorders of body representation also emerge following damage to the right parietal lobe. The possibility that parietal dysfunction might contribute to AN is suspected, based on the demonstrated association of spatial impairments, comparable to those found after parietal lesion, with this syndrome. We used a behavioral task to compare body knowledge in severe anorexics (n=8), healthy volunteers (n=11) and stroke patients with focal damage to the left/right parietal lobe (n=4). We applied a psychophysical procedure based on the perception, in the dark, of an approaching visual stimulus that was turned off before reaching the observer. Participants had to predict whether the stimulus would have hit/missed their body, had it continued its linear motion. Healthy volunteers and left parietal patients estimated body boundaries very close to the real ones. Conversely, anorexics and right parietal patients underestimated eccentricity of their left body boundary. These findings are in line with the role the parietal cortex plays in developing and maintaining body representation, and support the possibility for a neuropsychological component in the pathogenesis of anorexia, offering alternative approaches to treatment of the disorder.

  11. Visuo-Spatial Imagery Impairment in Posterior Cortical Atrophy: A Cognitive and SPECT Study

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    Simona Gardini

    2011-01-01

    Full Text Available This study investigated the cognitive profile and the cerebral perfusion pattern in a highly educated 70 year old gentleman with posterior cortical atrophy (PCA. Visuo-perceptual abilities, spatial memory, spatial representation and navigation, visuo-spatial mental imagery, semantic and episodic-autobiographical memory were assessed. Regional cerebral blood flow (rCBF was imaged with SPECT. Cognitive testing showed visual-perceptual impairment, apperceptive visual and landmark agnosia, topographical disorientation with way-finding deficits, impaired map learning and poor mental image generation. Semantic memory was normal, while episodic-autobiographical memory was impaired. Reduced rCBF was found mainly in the right hemisphere, in the precentral gyrus, posterior cingulate and middle temporal gyri, cuneus and precuneus, in the left superior temporal and lingual gyri and in the parahippocampus bilaterally. Hypoperfusion in occipito-parietal regions was associated with visuo-spatial deficits, whereas deficits in visuo-spatial mental imagery might reflect dysfunction related to hypoperfusion in the parahippocampus and precuneus, structures which are responsible for spatial and imagery processing. Dissociating performance between preserved semantic memory and poor episodic-autobiographical recall is consistent with a pattern of normal perfusion in frontal and anterior temporal regions but abnormal rCBF in the parahippocampi. The present findings indicate that PCA involves visuo-spatial imagery deficits and provide further validation to current neuro-cognitive models of spatial representation and topographical disorientation.

  12. From Cortical and Subcortical Grey Matter Abnormalities to Neurobehavioral Phenotype of Angelman Syndrome: A Voxel-Based Morphometry Study.

    Science.gov (United States)

    Aghakhanyan, Gayane; Bonanni, Paolo; Randazzo, Giovanna; Nappi, Sara; Tessarotto, Federica; De Martin, Lara; Frijia, Francesca; De Marchi, Daniele; De Masi, Francesco; Kuppers, Beate; Lombardo, Francesco; Caramella, Davide; Montanaro, Domenico

    2016-01-01

    Angelman syndrome (AS) is a rare neurogenetic disorder due to loss of expression of maternal ubiquitin-protein ligase E3A (UBE3A) gene. It is characterized by severe developmental delay, speech impairment, movement or balance disorder and typical behavioral uniqueness. Affected individuals show normal magnetic resonance imaging (MRI) findings, although mild dysmyelination may be observed. In this study, we adopted a quantitative MRI analysis with voxel-based morphometry (FSL-VBM) method to investigate disease-related changes in the cortical/subcortical grey matter (GM) structures. Since 2006 to 2013 twenty-six AS patients were assessed by our multidisciplinary team. From those, sixteen AS children with confirmed maternal 15q11-q13 deletions (mean age 7.7 ± 3.6 years) and twenty-one age-matched controls were recruited. The developmental delay and motor dysfunction were assessed using Bayley III and Gross Motor Function Measure (GMFM). Principal component analysis (PCA) was applied to the clinical and neuropsychological datasets. High-resolution T1-weighted images were acquired and FSL-VBM approach was applied to investigate differences in the local GM volume and to correlate clinical and neuropsychological changes in the regional distribution of GM. We found bilateral GM volume loss in AS compared to control children in the striatum, limbic structures, insular and orbitofrontal cortices. Voxel-wise correlation analysis with the principal components of the PCA output revealed a strong relationship with GM volume in the superior parietal lobule and precuneus on the left hemisphere. The anatomical distribution of cortical/subcortical GM changes plausibly related to several clinical features of the disease and may provide an important morphological underpinning for clinical and neurobehavioral symptoms in children with AS.

  13. It's how you get there: Walking down a virtual alley activates premotor and parietal areas

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    Johanna eWagner

    2014-02-01

    Full Text Available Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE feedback task on the EEG patterns during robot assisted walking. We compared walking in the VE modality to two control conditions: walking with a visual attention paradigm, in which visual stimuli were unrelated to the motor task; and walking with mirror feedback, in which participants observed their own movements. Eleven healthy participants were considered. Application of independent component analysis to the EEG revealed three independent component clusters in premotor and parietal areas showing increased activity during walking with the adaptive VE training paradigm compared to the control conditions. During the interactive VE walking task spectral power in frequency ranges 8-12Hz, 15-20Hz and 23-40Hz was significantly (p ≤ 0.05 decreased. This power decrease is interpreted as a correlate of an active cortical area. Furthermore activity in the premotor cortex revealed gait cycle related modulations significantly different (p ≤ 0.05 from baseline in the frequency range 23-40Hz during walking. These modulations were significantly (p ≤ 0.05 reduced depending on gait cycle phases in the interactive VE walking task compared to the control conditions.We demonstrate that premotor and parietal areas show increased activity during walking with the adaptive VE training paradigm, when compared to walking with mirror- and movement unrelated feedback. Previous research has related a premotor-parietal network to motor planning and motor intention. We argue that movement related interactive feedback enhances motor planning and motor intention. We hypothesize that this might improve gait recovery during rehabilitation.

  14. 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.)

  15. EEG source reconstruction reveals frontal-parietal dynamics of spatial conflict processing.

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    Michael X Cohen

    Full Text Available Cognitive control requires the suppression of distracting information in order to focus on task-relevant information. We applied EEG source reconstruction via time-frequency linear constrained minimum variance beamforming to help elucidate the neural mechanisms involved in spatial conflict processing. Human subjects performed a Simon task, in which conflict was induced by incongruence between spatial location and response hand. We found an early (∼200 ms post-stimulus conflict modulation in stimulus-contralateral parietal gamma (30-50 Hz, followed by a later alpha-band (8-12 Hz conflict modulation, suggesting an early detection of spatial conflict and inhibition of spatial location processing. Inter-regional connectivity analyses assessed via cross-frequency coupling of theta (4-8 Hz, alpha, and gamma power revealed conflict-induced shifts in cortical network interactions: Congruent trials (relative to incongruent trials had stronger coupling between frontal theta and stimulus-contrahemifield parietal alpha/gamma power, whereas incongruent trials had increased theta coupling between medial frontal and lateral frontal regions. These findings shed new light into the large-scale network dynamics of spatial conflict processing, and how those networks are shaped by oscillatory interactions.

  16. EEG source reconstruction reveals frontal-parietal dynamics of spatial conflict processing.

    Science.gov (United States)

    Cohen, Michael X; Ridderinkhof, K Richard

    2013-01-01

    Cognitive control requires the suppression of distracting information in order to focus on task-relevant information. We applied EEG source reconstruction via time-frequency linear constrained minimum variance beamforming to help elucidate the neural mechanisms involved in spatial conflict processing. Human subjects performed a Simon task, in which conflict was induced by incongruence between spatial location and response hand. We found an early (∼200 ms post-stimulus) conflict modulation in stimulus-contralateral parietal gamma (30-50 Hz), followed by a later alpha-band (8-12 Hz) conflict modulation, suggesting an early detection of spatial conflict and inhibition of spatial location processing. Inter-regional connectivity analyses assessed via cross-frequency coupling of theta (4-8 Hz), alpha, and gamma power revealed conflict-induced shifts in cortical network interactions: Congruent trials (relative to incongruent trials) had stronger coupling between frontal theta and stimulus-contrahemifield parietal alpha/gamma power, whereas incongruent trials had increased theta coupling between medial frontal and lateral frontal regions. These findings shed new light into the large-scale network dynamics of spatial conflict processing, and how those networks are shaped by oscillatory interactions.

  17. Intentional signals during saccadic and reaching delays in the human posterior parietal cortex.

    Science.gov (United States)

    Galati, Gaspare; Committeri, Giorgia; Pitzalis, Sabrina; Pelle, Gina; Patria, Fabiana; Fattori, Patrizia; Galletti, Claudio

    2011-12-01

    In the monkey posterior parietal cortex (PPC), there is clear evidence of anatomically segregated neuronal populations specialized for planning saccades and arm-reaching movements. However, functional neuroimaging studies in humans have yielded controversial results. Here we show that the human PPC contains distinct subregions responsive to salient visual cues, some of which combine spatial and action-related signals into 'intentional' signals. Participants underwent event-related functional magnetic resonance imaging while performing delayed saccades and long-range arm reaches instructed by visual cues. We focused on activity in the time period following the cue and preceding the actual movement. The use of individual cortical surface reconstructions with detailed sulcal labeling allowed the definition of six responsive regions with distinctive anatomical locations in the PPC. Each region exhibited a distinctive combination of transient and sustained signals during the delay, modulated by either the cue spatial location (contralateral vs. ipsilateral), the instructed action (saccades vs. reaching) or both. Importantly, a lateral and a medial dorsal parietal region showed sustained responses during the delay preferentially for contralateral saccadic and reaching trials, respectively. In the lateral region, preference for saccades was evident only as a more sustained response during saccadic vs. reaching delays, whereas the medial region also showed a higher transient response to cues signaling reaching vs. saccadic actions. These response profiles closely match the behavior of neurons in the macaque lateral and medial intraparietal area, respectively, and suggest that these corresponding human regions are encoding spatially directed action plans or 'intentions'.

  18. Timing of spatial priming within the fronto-parietal attention network: A TMS study.

    Science.gov (United States)

    Kehrer, Stefanie; Kraft, Antje; Koch, Stefan P; Kathmann, Norbert; Irlbacher, Kerstin; Brandt, Stephan A

    2015-07-01

    The posterior parietal cortex (PPC) and the dorsolateral prefrontal cortex (DLPFC) are known to be part of a cortical network involved in visual spatial attention. Top-down control can modulate processing at target and distractor positions over a sequence of trials, leading to positive priming at prior target positions and negative priming at prior distractor positions. In order to elucidate the exact time course of this top-down mechanism we here propose a transcranial magnetic stimulation (TMS) protocol. Single-pulses were applied over the right PPC, the right DLPFC or over the vertex (sham stimulation) at five time intervals (50, 100, 150, 200, 250 ms) after onset of a probe display during a spatial negative priming paradigm. Both suppression of the negative priming effect at a previous distractor position and enhancement of positive priming at a previous target position was found if a TMS pulse was applied 100 ms after the probe display onset either over the right DLPFC or the right PPC. We suggest that top-down mechanisms within the right fronto-parietal attention network are compromised during TMS interference in this time window.

  19. Patterns of Activity in the Human Frontal and Parietal Cortex Differentiate Large and Small Saccades

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    Marie-Helene Grosbras

    2016-10-01

    Full Text Available A vast literature indicates that small and large saccades, respectively, subserve different perceptual and cognitive strategies and may rely on different programming modes. While it is well established that in monkeys’ main oculomotor brain regions small and large eye movements are controlled by segregated neuronal populations, the representation of saccade amplitude in the human brain remains unclear. To address this question we used functional magnetic resonance imaging (fMRI to scan participants while they performed saccades towards targets at either short (4 degrees or large (30 degrees eccentricity. A regional multivoxel pattern analysis (MVPA reveals that patterns of activity in the frontal (FEF and parietal eye fields discriminate between the execution of large or small saccades. This was not the case in the supplementary eye fields nor in the inferior precentral cortex. These findings provide the first evidence of a representation of saccadic eye movement size in the fronto-parietal occulomotor circuit. They shed light on the respective roles of the different cortical oculomotor regions with respect to space perception and exploration, as well as on the homology of eye movement control between human and non-human primates.

  20. Parietal and Frontal Cortex Encode Stimulus-Specific Mnemonic Representations during Visual Working Memory.

    Science.gov (United States)

    Ester, Edward F; Sprague, Thomas C; Serences, John T

    2015-08-19

    Working memory (WM) enables the storage and manipulation of information in an active state. WM storage has long been associated with sustained increases in activation across a network of frontal and parietal cortical regions. However, recent evidence suggests that these regions primarily encode information related to general task goals rather than feature-selective representations of specific memoranda. These goal-related representations are thought to provide top-down feedback that coordinates the representation of fine-grained details in early sensory areas. Here, we test this model using fMRI-based reconstructions of remembered visual details from region-level activation patterns. We could reconstruct high-fidelity representations of a remembered orientation based on activation patterns in occipital visual cortex and in several sub-regions of frontal and parietal cortex, independent of sustained increases in mean activation. These results challenge models of WM that postulate disjoint frontoparietal "top-down control" and posterior sensory "feature storage" networks. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Mapping the functional neuroanatomy of spatial neglect and human parietal lobe functions: progress and challenges.

    Science.gov (United States)

    Vuilleumier, Patrik

    2013-08-01

    Spatial neglect is generally defined by various deficits in processing information from one (e.g., left) side of space contralateral to focal (e.g., right) hemisphere damage. Although classically associated with parietal lobe functions, there is now compelling evidence that neglect can follow lesions in many different cortical and subcortical sites, suggesting a dysfunction in distributed brain networks. In addition, neglect is likely to result from a combination of distinct deficits that co-occur due to concomitant damage affecting juxtaposed brain areas and their connections, but the exact nature of core deficits and their neural substrates still remains unclear. The present review describes recent progress in identifying functional components of the neglect syndrome and relating them to distinct subregions of parietal cortex. A comprehensive understanding of spatial neglect will require a more precise definition of cognitive processes implicated in different behavioral manifestations, as well as meticulous mapping of these processes onto specific brain circuits, while taking into account functional changes in activity that may arise in structurally intact areas subsequent to damage in distant portions of the relevant networks. © 2013 New York Academy of Sciences.

  2. Motor and parietal cortex stimulation for phantom limb pain and sensations.

    Science.gov (United States)

    Bolognini, Nadia; Olgiati, Elena; Maravita, Angelo; Ferraro, Francesco; Fregni, Felipe

    2013-08-01

    Limb amputation may lead to chronic painful sensations referred to the absent limb, ie phantom limb pain (PLP), which is likely subtended by maladaptive plasticity. The present study investigated whether transcranial direct current stimulation (tDCS), a noninvasive technique of brain stimulation that can modulate neuroplasticity, can reduce PLP. In 2 double-blind, sham-controlled experiments in subjects with unilateral lower or upper limb amputation, we measured the effects of a single session of tDCS (2 mA, 15 min) of the primary motor cortex (M1) and of the posterior parietal cortex (PPC) on PLP, stump pain, nonpainful phantom limb sensations and telescoping. Anodal tDCS of M1 induced a selective short-lasting decrease of PLP, whereas cathodal tDCS of PPC induced a selective short-lasting decrease of nonpainful phantom sensations; stump pain and telescoping were not affected by parietal or by motor tDCS. These findings demonstrate that painful and nonpainful phantom limb sensations are dissociable phenomena. PLP is associated primarily with cortical excitability shifts in the sensorimotor network; increasing excitability in this system by anodal tDCS has an antalgic effect on PLP. Conversely, nonpainful phantom sensations are associated to a hyperexcitation of PPC that can be normalized by cathodal tDCS. This evidence highlights the relationship between the level of excitability of different cortical areas, which underpins maladaptive plasticity following limb amputation and the phenomenology of phantom limb, and it opens up new opportunities for the use of tDCS in the treatment of PLP.

  3. Evolution of posterior parietal cortex and parietal-frontal networks for specific actions in primates.

    Science.gov (United States)

    Kaas, Jon H; Stepniewska, Iwona

    2016-02-15

    Posterior parietal cortex (PPC) is an extensive region of the human brain that develops relatively late and is proportionally large compared with that of monkeys and prosimian primates. Our ongoing comparative studies have led to several conclusions about the evolution of this posterior parietal region. In early placental mammals, PPC likely was a small multisensory region much like PPC of extant rodents and tree shrews. In early primates, PPC likely resembled that of prosimian galagos, in which caudal PPC (PPCc) is visual and rostral PPC (PPCr) has eight or more multisensory domains where electrical stimulation evokes different complex motor behaviors, including reaching, hand-to-mouth, looking, protecting the face or body, and grasping. These evoked behaviors depend on connections with functionally matched domains in premotor cortex (PMC) and motor cortex (M1). Domains in each region compete with each other, and a serial arrangement of domains allows different factors to influence motor outcomes successively. Similar arrangements of domains have been retained in New and Old World monkeys, and humans appear to have at least some of these domains. The great expansion and prolonged development of PPC in humans suggest the addition of functionally distinct territories. We propose that, across primates, PMC and M1 domains are second and third levels in a number of parallel, interacting networks for mediating and selecting one type of action over others.

  4. Neural correlates of conflict between gestures and words: A domain-specific role for a temporal-parietal complex

    Science.gov (United States)

    Noah, J. Adam; Dravida, Swethasri; Zhang, Xian; Yahil, Shaul; Hirsch, Joy

    2017-01-01

    The interpretation of social cues is a fundamental function of human social behavior, and resolution of inconsistencies between spoken and gestural cues plays an important role in successful interactions. To gain insight into these underlying neural processes, we compared neural responses in a traditional color/word conflict task and to a gesture/word conflict task to test hypotheses of domain-general and domain-specific conflict resolution. In the gesture task, recorded spoken words (“yes” and “no”) were presented simultaneously with video recordings of actors performing one of the following affirmative or negative gestures: thumbs up, thumbs down, head nodding (up and down), or head shaking (side-to-side), thereby generating congruent and incongruent communication stimuli between gesture and words. Participants identified the communicative intent of the gestures as either positive or negative. In the color task, participants were presented the words “red” and “green” in either red or green font and were asked to identify the color of the letters. We observed a classic “Stroop” behavioral interference effect, with participants showing increased response time for incongruent trials relative to congruent ones for both the gesture and color tasks. Hemodynamic signals acquired using functional near-infrared spectroscopy (fNIRS) were increased in the right dorsolateral prefrontal cortex (DLPFC) for incongruent trials relative to congruent trials for both tasks consistent with a common, domain-general mechanism for detecting conflict. However, activity in the left DLPFC and frontal eye fields and the right temporal-parietal junction (TPJ), superior temporal gyrus (STG), supramarginal gyrus (SMG), and primary and auditory association cortices was greater for the gesture task than the color task. Thus, in addition to domain-general conflict processing mechanisms, as suggested by common engagement of right DLPFC, socially specialized neural modules

  5. Basic visual function and cortical thickness patterns in posterior cortical atrophy.

    Science.gov (United States)

    Lehmann, Manja; Barnes, Josephine; Ridgway, Gerard R; Wattam-Bell, John; Warrington, Elizabeth K; Fox, Nick C; Crutch, Sebastian J

    2011-09-01

    Posterior cortical atrophy (PCA) is characterized by a progressive decline in higher-visual object and space processing, but the extent to which these deficits are underpinned by basic visual impairments is unknown. This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvement of visual networks in PCA. Cortical thickness analysis revealed trends toward lower cortical thickness in occipitotemporal (ventral) and occipitoparietal (dorsal) regions in patients with visuoperceptual and visuospatial deficits, respectively. However, there was also a lot of overlap in their patterns of cortical thinning. These findings suggest that different presentations of PCA represent points in a continuum of phenotypical variation.

  6. Bilateral, posterior parietal polymicrogyria as part of speech therapy ...

    African Journals Online (AJOL)

    Congenital bilateral perisylvian syndrome (CBPS) was traditionally ... mental language disorder. Magnetic ... parietal polymicrogyria in a child with speech pathology. .... did not recognise food in the mouth, no tongue movement was observed.

  7. Impaired speech repetition and left parietal lobe damage

    National Research Council Canada - National Science Library

    Fridriksson, Julius; Kjartansson, Olafur; Morgan, Paul S; Hjaltason, Haukur; Magnusdottir, Sigridur; Bonilha, Leonardo; Rorden, Christopher

    2010-01-01

    .... However, perfusion-weighted MRI revealed that tissue dysfunction, in the form of either frank damage or hypoperfusion, to the left inferior parietal lobe, rather than the underlying white matter...

  8. Antisaccade generation is impaired after parietal lobe lesions.

    Science.gov (United States)

    Sharpe, James A; Cheng, Ping; Eizenman, Moshe

    2011-09-01

    Antisaccades are directed away from visual targets. Impaired antisaccade generation has been attributed to frontal lobe damage. We studied antisaccades in patients with unilateral focal parietal lobe lesions. Normal subjects (N = 10) instructed to make 10° antisaccades opposite to a 100-ms target flash 10° to the right or left of center made antisaccades in 86.1% of trials. Patients (N = 13) made antisaccades contraversive to their lesions in 55.4% of trials and 50.5% of ipsiversive trials. In other trials, reflexive saccades occurred toward the target flash. Nine patients with imaged lesions overlapping in parietal lobe white matter showed subnormal antisaccade generation. Antisaccades provide a means of measuring voluntary saccade function of the parietal lobes independent of visual guidance. Impaired suppression of reflexive saccades and generation of antisaccades is attributed to disconnection of parietal lobe from frontal lobe ocular motor areas. © 2011 New York Academy of Sciences.

  9. Human cortical control of hand movements: parietofrontal networks for reaching, grasping, and pointing.

    Science.gov (United States)

    Filimon, Flavia

    2010-08-01

    In primates, control of the limb depends on many cortical areas. Whereas specialized parietofrontal circuits have been proposed for different movements in macaques, functional neuroimaging in humans has revealed widespread, overlapping activations for hand and eye movements and for movements such as reaching and grasping. This review examines the involvement of frontal and parietal areas in hand and arm movements in humans as revealed with functional neuroimaging. The degree of functional specialization, possible homologies with macaque cortical regions, and differences between frontal and posterior parietal areas are discussed, as well as a possible organization of hand movements with respect to different spatial reference frames. The available evidence supports a cortical organization along gradients of sensory (visual to somatosensory) and effector (eye to hand) preferences.

  10. 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.

  11. Gyri of the human parietal lobe: Volumes, spatial extents, automatic labelling, and probabilistic atlases.

    Science.gov (United States)

    Wild, Heather M; Heckemann, Rolf A; Studholme, Colin; Hammers, Alexander

    2017-01-01

    Accurately describing the anatomy of individual brains enables interlaboratory communication of functional and developmental studies and is crucial for possible surgical interventions. The human parietal lobe participates in multimodal sensory integration including language processing and also contains the primary somatosensory area. We describe detailed protocols to subdivide the parietal lobe, analyze morphological and volumetric characteristics, and create probabilistic atlases in MNI152 stereotaxic space. The parietal lobe was manually delineated on 3D T1 MR images of 30 healthy subjects and divided into four regions: supramarginal gyrus (SMG), angular gyrus (AG), superior parietal lobe (supPL) and postcentral gyrus (postCG). There was the expected correlation of male gender with larger brain and intracranial volume. We examined a wide range of anatomical features of the gyri and the sulci separating them. At least a rudimentary primary intermediate sulcus of Jensen (PISJ) separating SMG and AG was identified in nearly all (59/60) hemispheres. Presence of additional gyri in SMG and AG was related to sulcal features and volumetric characteristics. The parietal lobe was slightly (2%) larger on the left, driven by leftward asymmetries of the postCG and SMG. Intersubject variability was highest for SMG and AG, and lowest for postCG. Overall the morphological characteristics tended to be symmetrical, and volumes also tended to covary between hemispheres. This may reflect developmental as well as maturation factors. To assess the accuracy with which the labels can be used to segment newly acquired (unlabelled) T1-weighted brain images, we applied multi-atlas label propagation software (MAPER) in a leave-one-out experiment and compared the resulting automatic labels with the manually prepared ones. The results showed strong agreement (mean Jaccard index 0.69, corresponding to a mean Dice index of 0.82, average mean volume error of 0.6%). Stereotaxic probabilistic

  12. Functional integration of parietal lobe activity in early Alzheimer disease.

    Science.gov (United States)

    Jacobs, H I L; Van Boxtel, M P J; Heinecke, A; Gronenschild, E H B M; Backes, W H; Ramakers, I H G B; Jolles, J; Verhey, F R J

    2012-01-31

    Parietal lobe dysfunction is an important characteristic of early Alzheimer disease (AD). Functional studies have shown conflicting parietal activation patterns indicative of either compensatory or dysfunctional mechanisms. This study aimed at examining activation differences in early AD using a visuospatial task. We focused on functional characteristics of the parietal lobe and examined compensation or disconnection mechanisms by combining a fMRI task with effective connectivity measures from Granger causality mapping (GCM). Eighteen male patients with amnestic mild cognitive impairment (aMCI) and 18 male cognitively healthy older individuals were given a mental rotation task with different rotation angles. There were no behavioral group differences on the fMRI task. Separate measurements at each angle revealed widespread activation group differences. More temporal and parietal activation in the higher angle condition was observed in patients with aMCI. The parametric modulation, which identifies regions associated with increasing angle, confirmed these results. The GCM showed increased connectivity within the parietal lobe and between parietal and temporal regions in patients with aMCI. Decreased connectivity was found between the inferior parietal lobule and posterior cingulate gyrus. Connectivity patterns correlated with memory performance scores in patients with aMCI. Our results demonstrate increased effective temporoparietal connectivity in patients with aMCI, while maintaining intact behavioral performance. This might be a compensational mechanism to counteract a parietal-posterior cingulate gyrus disconnection. These findings highlight the importance of connectivity changes in the pathophysiology of AD. In addition, effective connectivity may be a promising method for evaluating interventions aimed at the promotion of compensatory mechanisms.

  13. A volumetric study of parietal lobe subregions in Turner syndrome

    OpenAIRE

    Brown, Wendy E.; Shelli R Kesler; Eliez, Stephan; Warsofsky, Ilana S.; Haberecht, Michael; Reiss, Allan L.

    2004-01-01

    Turner syndrome, a genetic disorder that results from the complete or partial absence of an X chromosome in females, has been associated with specific impairment in visuospatial cognition. Previous studies have demonstrated a relationship between parietal lobe abnormalities and visuospatial deficits in Turner syndrome. We used high-resolution magnetic resonance imaging to measure parietal lobe subdivisions in 14 participants with Turner syndrome (mean age 13 years 5 months, SD 5 years) and 14...

  14. Perceptual distortions and delusional thinking following ketamine administration are related to increased pharmacological MRI signal changes in the parietal lobe.

    Science.gov (United States)

    Stone, James; Kotoula, Vasileia; Dietrich, Craige; De Simoni, Sara; Krystal, John H; Mehta, Mitul A

    2015-09-01

    Ketamine produces effects in healthy humans that resemble the positive, negative and cognitive symptoms of schizophrenia. We investigated the effect of ketamine administration on brain activity as indexed by blood-oxygen-level-dependent (BOLD) signal change response, and its relationship to ketamine-induced subjective changes, including perceptual distortion. Thirteen healthy participants volunteered for the study. All underwent a 15-min functional MRI acquisition with a ketamine infusion commencing after 5 min (approx 0.26 mg/kg over 20s followed by an infusion of approx. 0.42 mg/kg/h). Following the scan, participants self-rated ketamine-induced effects using the Psychotomimetic States Inventory. Ketamine led to widespread cortical and subcortical increases in BOLD response (FWE-corrected p parietal cortices reflect ketamine effects on circuits that contribute to its capacity to produce perceptual alterations and delusional interpretations. © The Author(s) 2015.

  15. Parietal lesion effects on cued recall following pair associate learning.

    Science.gov (United States)

    Ben-Zvi, Shir; Soroker, Nachum; Levy, Daniel A

    2015-07-01

    We investigated the involvement of the posterior parietal cortex in episodic memory in a lesion-effects study of cued recall following pair-associate learning. Groups of patients who had experienced first-incident stroke, generally in middle cerebral artery territory, and exhibited damage that included lateral posterior parietal regions, were tested within an early post-stroke time window. In three experiments, patients and matched healthy comparison groups executed repeated study and cued recall test blocks of pairs of words (Experiment 1), pairs of object pictures (Experiment 2), or pairs of object pictures and environmental sounds (Experiment 3). Patients' brain CT scans were subjected to quantitative analysis of lesion volumes. Behavioral and lesion data were used to compute correlations between area lesion extent and memory deficits, and to conduct voxel-based lesion-symptom mapping. These analyses implicated lateral ventral parietal cortex, especially the angular gyrus, in cued recall deficits, most pronouncedly in the cross-modal picture-sound pairs task, though significant parietal lesion effects were also found in the unimodal word pairs and picture pairs tasks. In contrast to an earlier study in which comparable parietal lesions did not cause deficits in item recognition, these results indicate that lateral posterior parietal areas make a substantive contribution to demanding forms of recollective retrieval as represented by cued recall, especially for complex associative representations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Sex differences in parietal lobe structure and development.

    Science.gov (United States)

    Salinas, Joel; Mills, Elizabeth D; Conrad, Amy L; Koscik, Timothy; Andreasen, Nancy C; Nopoulos, Peg

    2012-02-01

    Structural magnetic resonance imaging studies provide evidence for sex differences in the human brain. Differences in surface area and the proportion of gray to white matter volume are observed, in particular in the parietal lobe. To our knowledge, no studies have examined sex differences in parietal lobe structure in younger populations or in the context of development. The present study evaluated sex differences in the structure of the parietal lobe in children aged 7 to 17 years. In addition, by adding a cohort of previously studied adults aged 18 to 50 years, sex differences in parietal lobe structure were examined across the age span of 7 to 50 years. Compared with the adult sample, the younger sample showed that the ratio of parietal lobe cortex to white matter was greater in female brains, but no sex differences in surface area. When examining the effects of age, surface area exhibited a significant sex-age interaction. In male brains, there was essentially no decrease in surfaces area over time, whereas in female brains, there was a significant decrease in surface area over time. These findings support the notion of structural sex differences in the parietal lobe, not only in the context of cross-sectional assessment but also in terms of differences in developmental trajectories. Copyright © 2012 Elsevier HS Journals, Inc. All rights reserved.

  17. Whisker-related afferents in superior colliculus.

    Science.gov (United States)

    Castro-Alamancos, Manuel A; Favero, Morgana

    2016-05-01

    Rodents use their whiskers to explore the environment, and the superior colliculus is part of the neural circuits that process this sensorimotor information. Cells in the intermediate layers of the superior colliculus integrate trigeminotectal afferents from trigeminal complex and corticotectal afferents from barrel cortex. Using histological methods in mice, we found that trigeminotectal and corticotectal synapses overlap somewhat as they innervate the lower and upper portions of the intermediate granular layer, respectively. Using electrophysiological recordings and optogenetics in anesthetized mice in vivo, we showed that, similar to rats, whisker deflections produce two successive responses that are driven by trigeminotectal and corticotectal afferents. We then employed in vivo and slice experiments to characterize the response properties of these afferents. In vivo, corticotectal responses triggered by electrical stimulation of the barrel cortex evoke activity in the superior colliculus that increases with stimulus intensity and depresses with increasing frequency. In slices from adult mice, optogenetic activation of channelrhodopsin-expressing trigeminotectal and corticotectal fibers revealed that cells in the intermediate layers receive more efficacious trigeminotectal, than corticotectal, synaptic inputs. Moreover, the efficacy of trigeminotectal inputs depresses more strongly with increasing frequency than that of corticotectal inputs. The intermediate layers of superior colliculus appear to be tuned to process strong but infrequent trigeminal inputs and weak but more persistent cortical inputs, which explains features of sensory responsiveness, such as the robust rapid sensory adaptation of whisker responses in the superior colliculus. Copyright © 2016 the American Physiological Society.

  18. Attention to Multiple Objects Facilitates Their Integration in Prefrontal and Parietal Cortex.

    Science.gov (United States)

    Kim, Yee-Joon; Tsai, Jeffrey J; Ojemann, Jeffrey; Verghese, Preeti

    2017-05-10

    Selective attention is known to interact with perceptual organization. In visual scenes, individual objects that are distinct and discriminable may occur on their own, or in groups such as a stack of books. The main objective of this study is to probe the neural interaction that occurs between individual objects when attention is directed toward one or more objects. Here we record steady-state visual evoked potentials via electrocorticography to directly assess the responses to individual stimuli and to their interaction. When human participants attend to two adjacent stimuli, prefrontal and parietal cortex shows a selective enhancement of only the neural interaction between stimuli, but not the responses to individual stimuli. When only one stimulus is attended, the neural response to that stimulus is selectively enhanced in prefrontal and parietal cortex. In contrast, early visual areas generally manifest responses to individual stimuli and to their interaction regardless of attentional task, although a subset of the responses is modulated similarly to prefrontal and parietal cortex. Thus, the neural representation of the visual scene as one progresses up the cortical hierarchy becomes more highly task-specific and represents either individual stimuli or their interaction, depending on the behavioral goal. Attention to multiple objects facilitates an integration of objects akin to perceptual grouping.SIGNIFICANCE STATEMENT Individual objects in a visual scene are seen as distinct entities or as parts of a whole. Here we examine how attention to multiple objects affects their neural representation. Previous studies measured single-cell or fMRI responses and obtained only aggregate measures that combined the activity to individual stimuli as well as their potential interaction. Here, we directly measure electrocorticographic steady-state responses corresponding to individual objects and to their interaction using a frequency-tagging technique. Attention to two

  19. Extrastriate cortical areas activated during visual discrimination in man

    DEFF Research Database (Denmark)

    Roland, PE

    1981-01-01

    The regional cerebral blood flow (rCBF) was measured in 254 different regions of the human extrastriate cerebral cortex during rest and during visual shape discrimination. Visual shape discrimination increased the rCBF markedly in the frontal eye fields, the upper part of the prefrontal cortex......, the lateral occipital cortex and the superior parietal cortex. Moderate increases of rCBF appeared in the inferotemporal cortex, the parietotemporo-occipital region and scattered in the lateral part of the prefrontal cortex....

  20. Heterogeneous afferents to the inferior parietal lobule of the rhesus monkey revealed by the retrograde transport method.

    Science.gov (United States)

    Divac, I; Lavail, J H; Rakic, P; Winston, K R

    1977-03-11

    The sources of afferent connections to the inferior parietal lobule (rostral part of the area 7 of Brodman; PF and rostral part of PG of von Bonin and Bailey) were examined with the retrograde transport method in infant and adult rhesus monkeys. Two to 3 days after injections of horseradish peroxidase (HRP) into the cortex, the animals were anesthetized, and the brains fixed and processed for the histochemical demonstration of the enzyme marker. Labeled neurons were found in layer III in the ipsilateral prefrontal, parietal, occipital and temporal cortices, notably in areas 5, 19, 22 and 46 of Brodmann, and in area 7 of the contralateral parietal cortex. In the thalamus, HRP-positive cells were located ipsilaterally in the medial pulvinar nucleus in the nuclei centrum medianum and parafascicularis, as well as in the rostral thalamus, lateral and medial to the mammillothalamic tract, in the nucleus ventralis anterior and nucleus paracentralis. Numerous labeled cells were also identified in the magnocellular nuclei of the basal forebrain, in the dorsal and medial raphe nuclei, and in the locus coeruleus. Most of the cells in these regions were located in the hemisphere ipsilateral to the injections, but a number of them were also found in the contralateral hemispher. In adult monkeys, brownish granules in the cytoplasm of some cells were interpreted as endogenous pigment or due to various pigment precursors. However, all 14 locations listed above were identified in the infant monkey in which endogenous pigment was not a confounding factor.

  1. Parallel and serial processing of haptic information in man: effects of parietal lesions on sensorimotor hand function.

    Science.gov (United States)

    Knecht, S; Kunesch, E; Schnitzler, A

    1996-07-01

    Recent animal studies have shown that there is an evolutionary shift within the order of primates from parallel to serial processing of haptic information. In an attempt to determine whether there is also evidence of serial processing in humans 10 patients with parietal cortical lesions, three patients with subcortical lesions and one patient after hemispherectomy, were examined. Case-by-case and across subject analysis of lesion type, sensorimotor profile and electrophysiological findings showed that in unihemispheric lesions: (a) there is little impairment of thermesthesia, nociception and vibration sense: (b) two-point discrimination and integrity of the N20 somatosensory component are highly correlated; (c) a loss of the N20 component is accompanied by a severe impairment of stereognosis; (d) conversely, in more posterior lesions astereognosis can occur with an intact N20 component; and (e) if the lesion is in the right hemisphere there is frequently impairment of graphesthesia in both hands. These data are taken to indicate serial processing from SI (as evidenced by an intact N20 component) to posterior parietal cortex allowing progressive spatial and temporal integration. In graphesthesia our data suggest an integrative function of the right parietal cortex for both sides of the body. Other sensory qualities like vibration nociception and thermesthesia are apparently processed in a non-serial, probably parallel way involving both hemispheres. The effects of cerebral lesions in our series suggest parallel as well as serial processing of somesthetic information in man underlying the perception of different haptic features.

  2. RNA-Seq analysis of the parietal cortex in Alzheimer's disease reveals alternatively spliced isoforms related to lipid metabolism.

    Science.gov (United States)

    Mills, James D; Nalpathamkalam, Thomas; Jacobs, Heidi I L; Janitz, Caroline; Merico, Daniele; Hu, Pingzhao; Janitz, Michael

    2013-03-01

    The parietal cortex of the human brain plays a unique role in the coordination of movement and in the integration of signals from the other cortices. Because of its extensive connections and involvement in many higher-order cognitive functions, neurodegenerative changes in the parietal lobe are believed to be crucial in the early symptoms of Alzheimer's disease (AD). Little is known about the transcriptome of this part of the human brain or how it is perturbed by the neurodegenerative process. To that end, we performed mRNA sequencing using the Illumina RNA-Seq technique on samples derived from normal and AD parietal lobes. Gene expression analysis evaluating alternatively spliced isoform expression and promoter usage revealed surprisingly elevated transcriptome activity in the AD condition. This phenomenon was particularly apparent in the alternative usage of transcriptional start sites. A Gene Ontology analysis of the differentially expressed genes revealed enrichment in the functional pathways related to lipid metabolism, thus highlighting the importance of astrocyte activity in the neurodegenerative process. We also identified an upregulation of the diazepam-binding inhibitor (DBI) gene in AD, as the result of a splicing switch toward shorter, intron-retaining isoforms driven by alternative promoters and was coupled with a simultaneous decrease in the abundance of protein-coding transcripts. These two DBI isoforms have not been described previously.

  3. Independent measurement of femoral cortical thickness and cortical bone density using clinical CT.

    Science.gov (United States)

    Treece, G M; Gee, A H

    2015-02-01

    The local structure of the proximal femoral cortex is of interest since both fracture risk, and the effects of various interventions aimed at reducing that risk, are associated with cortical properties focused in particular regions rather than dispersed over the whole bone. Much of the femoral cortex is less than 3mm thick, appearing so blurred in clinical CT that its actual density is not apparent in the data, and neither thresholding nor full-width half-maximum techniques are capable of determining its width. Our previous work on cortical bone mapping showed how to produce more accurate estimates of cortical thickness by assuming a fixed value of the cortical density for each hip. However, although cortical density varies much less over the proximal femur than thickness, what little variation there is leads to errors in thickness measurement. In this paper, we develop the cortical bone mapping technique by exploiting local estimates of imaging blur to correct the global density estimate, thus providing a local density estimate as well as more accurate estimates of thickness. We also consider measurement of cortical mass surface density and the density of trabecular bone immediately adjacent to the cortex. Performance is assessed with ex vivo clinical QCT scans of proximal femurs, with true values derived from high resolution HRpQCT scans of the same bones. We demonstrate superior estimation of thickness than is possible with alternative techniques (accuracy 0.12 ± 0.39 mm for cortices in the range 1-3mm), and that local cortical density estimation is feasible for densities >800 mg/cm(3).

  4. Atypical balance between occipital and fronto-parietal activation for visual shape extraction in dyslexia.

    Science.gov (United States)

    Zhang, Ying; Whitfield-Gabrieli, Susan; Christodoulou, Joanna A; Gabrieli, John D E

    2013-01-01

    Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow's direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading.

  5. Atypical balance between occipital and fronto-parietal activation for visual shape extraction in dyslexia.

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    Full Text Available Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI to examine brain activation while adults with or without dyslexia responded to the change of an arrow's direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading.

  6. Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia

    Science.gov (United States)

    Zhang, Ying; Whitfield-Gabrieli, Susan; Christodoulou, Joanna A.; Gabrieli, John D. E.

    2013-01-01

    Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading. PMID:23825653

  7. The role of temporo-parietal junction (TPJ) in global Gestalt perception.

    Science.gov (United States)

    Huberle, Elisabeth; Karnath, Hans-Otto

    2012-07-01

    Grouping processes enable the coherent perception of our environment. A number of brain areas has been suggested to be involved in the integration of elements into objects including early and higher visual areas along the ventral visual pathway as well as motion-processing areas of the dorsal visual pathway. However, integration not only is required for the cortical representation of individual objects, but is also essential for the perception of more complex visual scenes consisting of several different objects and/or shapes. The present fMRI experiments aimed to address such integration processes. We investigated the neural correlates underlying the global Gestalt perception of hierarchically organized stimuli that allowed parametrical degrading of the object at the global level. The comparison of intact versus disturbed perception of the global Gestalt revealed a network of cortical areas including the temporo-parietal junction (TPJ), anterior cingulate cortex and the precuneus. The TPJ location corresponds well with the areas known to be typically lesioned in stroke patients with simultanagnosia following bilateral brain damage. These patients typically show a deficit in identifying the global Gestalt of a visual scene. Further, we found the closest relation between behavioral performance and fMRI activation for the TPJ. Our data thus argue for a significant role of the TPJ in human global Gestalt perception.

  8. Three-Dimensional Eye Position Signals Shape Both Peripersonal Space and Arm Movement Activity in the Medial Posterior Parietal Cortex.

    Directory of Open Access Journals (Sweden)

    Kostas eHadjidimitrakis

    2012-06-01

    Full Text Available Research conducted over the last decades has established that the medial part of posterior parietal cortex is crucial for controlling visually guided actions in human and non-human primates. Within this cortical sector there is area V6A, a crucial node of the parietofrontal network involved in arm movement control in both monkeys and humans. However, the encoding of action-in-depth by V6A cells had been not studied till recently. Recent neurophysiological studies show the existence in V6A neurons of signals related to the distance of targets from the eyes. These signals are integrated, often at the level of single cells, with information about the direction of gaze, thus encoding spatial location in 3D space. Moreover, 3D eye position signals seem to be further exploited at two additional levels of neural processing: a in determining whether targets are located in the peripersonal space or not, and b in shaping the spatial tuning of arm movement related activity towards reachable targets. These findings are in line with studies in putative homolog regions in humans and together point to a role of medial posterior parietal cortex in encoding both the vergence angle of the eyes and peripersonal space. Besides this role in spatial encoding also in depth, several findings demonstrate the involvement of this cortical sector in non-spatial processes.

  9. Dissociable Memory- and Response-Related Activity in Parietal Cortex during Auditory Spatial Working Memory

    Directory of Open Access Journals (Sweden)

    Claude Alain

    2010-12-01

    Full Text Available Attending and responding to sound location generates increased activity in parietal cortex which may index auditory spatial working memory and/or goal-directed action. Here, we used an n-back task (Experiment 1 and an adaptation paradigm (Experiment 2 to distinguish memory-related activity from that associated with goal-directed action. In Experiment 1, participants indicated, in separate blocks of trials, whether the incoming stimulus was presented at the same location as in the previous trial (1-back or two trials ago (2-back. Prior to a block of trials, participants were told to use their left or right index finger. Accuracy and reaction times were worse for the 2-back than for the 1-back condition. The analysis of fMRI data revealed greater sustained task-related activity in the inferior parietal lobule (IPL and superior frontal sulcus during 2-back than 1-back after accounting for response-related activity elicited by the targets. Target detection and response execution were also associated with enhanced activity in the IPL bilaterally, though the activation was anterior to that associated with sustained task-related activity. In Experiment 2, we used an event-related design in which participants listened (no response required to trials that comprised four sounds presented either at the same location or at four different locations. We found larger IPL activation for changes in sound location than for sounds presented at the same location. The IPL activation overlapped with that observed during auditory spatial working memory task. Together, these results provide converging evidence supporting the role of parietal cortex in auditory spatial working memory which can be dissociated from response selection and execution.

  10. Superior Hiking Trail

    Data.gov (United States)

    Minnesota Department of Natural Resources — Superior Hiking Trail main trail, spurs, and camp spurs for completed trail throughout Cook, Lake, St. Louis and Carlton counties. These data were collected with...

  11. Bathymetry of Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  12. Superior Hiking Trail Facilities

    Data.gov (United States)

    Minnesota Department of Natural Resources — Superior Hiking Trail main trail, spurs, and camp spurs for completed trail throughout Cook, Lake, St. Louis and Carlton counties. These data were collected with...

  13. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject.

    Science.gov (United States)

    Ioannides, Andreas A; Liu, Lichan; Poghosyan, Vahe; Saridis, George A; Gjedde, Albert; Ptito, Maurice; Kupers, Ron

    2013-01-01

    Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG) data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1) and motor (M1) cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45-70 Hz activity at latencies of 20-50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA) 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong, and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI) revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occurred in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

  14. MEG reveals a fast pathway from somatosensory cortex to occipital areas via posterior parietal cortex in a blind subject

    Directory of Open Access Journals (Sweden)

    Andreas A Ioannides

    2013-08-01

    Full Text Available Cross-modal activity in visual cortex of blind subjects has been reported during performance of variety of non-visual tasks. A key unanswered question is through which pathways non-visual inputs are funneled to the visual cortex. Here we used tomographic analysis of single trial magnetoencephalography (MEG data recorded from one congenitally blind and two sighted subjects after stimulation of the left and right median nerves at three intensities: below sensory threshold, above sensory threshold and above motor threshold; the last sufficient to produce thumb twitching. We identified reproducible brain responses in the primary somatosensory (S1 and motor (M1 cortices at around 20 ms post-stimulus, which were very similar in sighted and blind subjects. Time-frequency analysis revealed strong 45 to 70 Hz activity at latencies of 20 to 50 ms in S1 and M1, and posterior parietal cortex Brodmann areas (BA 7 and 40, which compared to lower frequencies, were substantially more pronounced in the blind than the sighted subjects. Critically, at frequencies from α-band up to 100 Hz we found clear, strong and widespread responses in the visual cortex of the blind subject, which increased with the intensity of the somatosensory stimuli. Time-delayed mutual information (MI revealed that in blind subject the stimulus information is funneled from the early somatosensory to visual cortex through posterior parietal BA 7 and 40, projecting first to visual areas V5 and V3, and eventually V1. The flow of information through this pathway occured in stages characterized by convergence of activations into specific cortical regions. In sighted subjects, no linked activity was found that led from the somatosensory to the visual cortex through any of the studied brain regions. These results provide the first evidence from MEG that in blind subjects, tactile information is routed from primary somatosensory to occipital cortex via the posterior parietal cortex.

  15. Temporal order processing of syllables in the left parietal lobe.

    Science.gov (United States)

    Moser, Dana; Baker, Julie M; Sanchez, Carmen E; Rorden, Chris; Fridriksson, Julius

    2009-10-07

    Speech processing requires the temporal parsing of syllable order. Individuals suffering from posterior left hemisphere brain injury often exhibit temporal processing deficits as well as language deficits. Although the right posterior inferior parietal lobe has been implicated in temporal order judgments (TOJs) of visual information, there is limited evidence to support the role of the left inferior parietal lobe (IPL) in processing syllable order. The purpose of this study was to examine whether the left inferior parietal lobe is recruited during temporal order judgments of speech stimuli. Functional magnetic resonance imaging data were collected on 14 normal participants while they completed the following forced-choice tasks: (1) syllable order of multisyllabic pseudowords, (2) syllable identification of single syllables, and (3) gender identification of both multisyllabic and monosyllabic speech stimuli. Results revealed increased neural recruitment in the left inferior parietal lobe when participants made judgments about syllable order compared with both syllable identification and gender identification. These findings suggest that the left inferior parietal lobe plays an important role in processing syllable order and support the hypothesized role of this region as an interface between auditory speech and the articulatory code. Furthermore, a breakdown in this interface may explain some components of the speech deficits observed after posterior damage to the left hemisphere.

  16. Cognitive and metacognitive activity in mathematical problem solving: prefrontal and parietal patterns.

    Science.gov (United States)

    Anderson, John R; Betts, Shawn; Ferris, Jennifer L; Fincham, Jon M

    2011-03-01

    Students were taught an algorithm for solving a new class of mathematical problems. Occasionally in the sequence of problems, they encountered exception problems that required that they extend the algorithm. Regular and exception problems were associated with different patterns of brain activation. Some regions showed a Cognitive pattern of being active only until the problem was solved and no difference between regular or exception problems. Other regions showed a Metacognitive pattern of greater activity for exception problems and activity that extended into the post-solution period, particularly when an error was made. The Cognitive regions included some of parietal and prefrontal regions associated with the triple-code theory of (Dehaene, S., Piazza, M., Pinel, P., & Cohen, L. (2003). Three parietal circuits for number processing. Cognitive Neuropsychology, 20, 487-506) and associated with algebra equation solving in the ACT-R theory (Anderson, J. R. (2005). Human symbol manipulation within an 911 integrated cognitive architecture. Cognitive science, 29, 313-342. Metacognitive regions included the superior prefrontal gyrus, the angular gyrus of the triple-code theory, and frontopolar regions.

  17. rTMS over bilateral inferior parietal cortex induces decrement of spatial sustained attention

    Science.gov (United States)

    Lee, Jeyeon; Ku, Jeonghun; Han, Kiwan; Park, Jinsick; Lee, Hyeongrae; Kim, Kyung Ran; Lee, Eun; Husain, Masud; Yoon, Kang Jun; Kim, In Young; Jang, Dong Pyo; Kim, Sun I.

    2013-01-01

    Sustained attention is an essential brain function that enables a subject to maintain attention level over the time of a task. In previous work, the right inferior parietal lobe (IPL) has been reported as one of the main brain regions related to sustained attention, however, the right lateralization of vigilance/sustained attention is unclear because information about the network for sustained attention is traditionally provided by neglect patients who typically have right brain damage. Here, we investigated sustained attention by applying a virtual lesion technique, transcranial magnetic stimulation (TMS), over the left and right superior parietal lobe (SPL) and IPL. We used two different types of visual sustained attention tasks: spatial (location based) and non-spatial (feature based). When the participants performed the spatial task, repetitive TMS (rTMS) over either the right or left IPL induced a significant decrement of sustained attention causing a progressive increment of errors and response time. In contrast, participants' performance was not changed by rTMS on the non-spatial task. Also, omission errors (true negative) gradually increased with time on right and left IPL rTMS conditions, while commission errors (false positive) were relatively stable. These findings suggest that the maintenance of attention, especially in tasks regarding spatial location, is not uniquely lateralized to the right IPL, but may also involve participation of the left IPL. PMID:23403477

  18. Expert cognitive control and individual differences associated with frontal and parietal white matter microstructure.

    Science.gov (United States)

    Roberts, R Edward; Anderson, Elaine J; Husain, Masud

    2010-12-15

    Although many functional imaging studies have reported frontal activity associated with "cognitive control" tasks, little is understood about factors underlying individual differences in performance. Here we compared the behavior and brain structure of healthy controls with fighter pilots, an expert group trained to make precision choices at speed in the presence of conflicting cues. Two different behavioral paradigms--Eriksen Flanker and change of plan tasks--were used to assess the influence of distractors and the ability to update ongoing action plans. Fighter pilots demonstrated superior cognitive control as indexed by accuracy and postconflict adaptation on the Flanker task, but also showed increased sensitivity to irrelevant, distracting choices. By contrast, when pilots were examined on their ability to inhibit a current action plan in favor of an alternative response, their performance was no better than the control group. Diffusion weighted imaging revealed differences in white matter radial diffusivity between pilots and controls not only in the right dorsomedial frontal region but also in the right parietal lobe. Moreover, analysis of individual differences in reaction time costs for conflict trials on the Flanker task demonstrated significant correlations with radial diffusivity at these locations, but in different directions. Postconflict adaptation effects, however, were confined to the dorsomedial frontal locus. The findings demonstrate that in humans expert cognitive control may surprisingly be mediated by enhanced response gain to both relevant and irrelevant stimuli, and is accompanied by structural alterations in the white matter of the frontal and parietal lobe.

  19. Reduced parietal connectivity with a premotor writing area in writer's cramp.

    Science.gov (United States)

    Delnooz, Cathérine C S; Helmich, Rick C; Toni, Ivan; van de Warrenburg, Bart P C

    2012-09-15

    Writer's cramp is a task-specific form of dystonia with symptoms characterized by abnormal movements and postures of the hand and arm evident only during writing. Its pathophysiology has been related to faulty sensorimotor integration, abnormal sensory processing, and impaired motor planning. Its symptoms might appear when the computational load of writing pushes a tonically altered circuit outside its operational range. Using resting-state fMRI, we tested whether writer's cramp patients have altered intrinsic functional connectivity in the premotor-parietal circuit. Sixteen patients with right-sided writer's cramp and 19 control subjects were studied. We show that writer's cramp patients have reduced connectivity between the superior parietal lobule and a dorsal precentral region that controls writing movements. This difference between patients and controls occurred in the absence of writing and only in the hemisphere contralateral to the affected hand. This finding adds a novel element to the pathophysiological substrate for writer's cramp, namely, task-independent alterations within a writing-related circuit.

  20. rTMS over bilateral inferior parietal cortex induces decrement of spatial sustained attention

    Directory of Open Access Journals (Sweden)

    Jeyeon eLee

    2013-02-01

    Full Text Available Sustained attention is an essential brain function that enables a subject to maintain attention level over the time of a task. In previous work, the right inferior parietal lobe (IPL has been reported as one of the main brain regions related to sustained attention, however, the right lateralization of vigilance/sustained attention is unclear because information about the network for sustained attention is traditionally provided by neglect patients who typically have right brain damage. Here, we investigated sustained attention by applying a virtual lesion technique, transcranial magnetic stimulation (TMS, over the left and right superior parietal lobe (SPL and IPL. We used two different types of visual sustained attention tasks: spatial (location based and non-spatial (feature based. When the participants performed the spatial task, repetitive TMS (rTMS over either the right or left IPL induced a significant decrement of sustained attention causing a progressive increment of errors and response time. In contrast, participants’ performance was not changed by rTMS on the non-spatial task. Also, omission errors (true negative gradually increased with time on right and left IPL rTMS conditions, while commission errors (false positive were relatively stable. These findings suggest that the maintenance of attention, especially in tasks regarding spatial location, is not uniquely lateralized to the right IPL, but may also involve participation of the left IPL as well.

  1. Creating Colored Letters: Familial Markers of Grapheme-Color Synesthesia in Parietal Lobe Activation and Structure.

    Science.gov (United States)

    Colizoli, Olympia; Murre, Jaap M J; Scholte, H Steven; Rouw, Romke

    2017-07-01

    Perception is inherently subjective, and individual differences in phenomenology are well illustrated by the phenomenon of synesthesia (highly specific, consistent, and automatic cross-modal experiences, in which the external stimulus corresponding to the additional sensation is absent). It is unknown why some people develop synesthesia and others do not. In the current study, we tested whether neural markers related to having synesthesia in the family were evident in brain function and structure. Relatives of synesthetes (who did not have any type of synesthesia themselves) and matched controls read specially prepared books with colored letters for several weeks and were scanned before and after reading using magnetic resonance imaging. Effects of acquired letter-color associations were evident in brain activation. Training-related activation (while viewing black letters) in the right angular gyrus of the parietal lobe was directly related to the strength of the learned letter-color associations (behavioral Stroop effect). Within this obtained angular gyrus ROI, the familial trait of synesthesia related to brain activation differences while participants viewed both black and colored letters. Finally, we compared brain structure using voxel-based morphometry and diffusion tensor imaging to test for group differences and training effects. One cluster in the left superior parietal lobe had significantly more coherent white matter in the relatives compared with controls. No evidence for experience-dependent plasticity was obtained. For the first time, we present evidence suggesting that the (nonsynesthete) relatives of grapheme-color synesthetes show atypical grapheme processing as well as increased brain connectivity.

  2. A parcellation scheme for human left lateral parietal cortex.

    Science.gov (United States)

    Nelson, Steven M; Cohen, Alexander L; Power, Jonathan D; Wig, Gagan S; Miezin, Francis M; Wheeler, Mark E; Velanova, Katerina; Donaldson, David I; Phillips, Jeffrey S; Schlaggar, Bradley L; Petersen, Steven E

    2010-07-15

    The parietal lobe has long been viewed as a collection of architectonic and functional subdivisions. Though much parietal research has focused on mechanisms of visuospatial attention and control-related processes, more recent functional neuroimaging studies of memory retrieval have reported greater activity in left lateral parietal cortex (LLPC) when items are correctly identified as previously studied ("old") versus unstudied ("new"). These studies have suggested functional divisions within LLPC that may provide distinct contributions toward recognition memory judgments. Here, we define regions within LLPC by developing a parcellation scheme that integrates data from resting-state functional connectivity MRI and functional MRI. This combined approach results in a 6-fold parcellation of LLPC based on the presence (or absence) of memory-retrieval-related activity, dissociations in the profile of task-evoked time courses, and membership in large-scale brain networks. This parcellation should serve as a roadmap for future investigations aimed at understanding LLPC function.

  3. Inter-hemispheric remapping between arm proprioception and vision of the hand is disrupted by single pulse TMS on the left parietal cortex.

    Science.gov (United States)

    Fautrelle, Lilian; Gueugnon, Mathieu; Barbieri, Guillaume; Bonnetblanc, François

    2013-07-01

    Parietal cortical areas are involved in sensori-motor transformations for their respective contralateral hemifield/body. When arms of the subjects are crossed while their gaze is fixed straight ahead, vision of the hand is processed by the hemisphere ipsilateral to the arm position and proprioception of the arm by the contralateral hemisphere. It induces interhemispheric transfer and remapping. Our objective was to investigate whether a single pulse TMS applied to the left parietal cortical area would disturb interhemispheric remapping in a similar case, and would increase a simple reaction time (RT) with respect to a control single pulse TMS applied to the frontal cortical area. Two LED were superimposed and located in front of the subjects on the saggital axis. Subjects were asked to carefully fixate on these LED during each trial. The lighting of the red LED was used as a warning signal. Following the green one was illuminated after a variable delay and served as a go-signal. The hand for the response was determined before the start of each trial. TMS was applied to the left parietal, the left frontal cortical areas, or not applied to the subject. Results revealed that: (1) Irrespective of its location, single pulse TMS induced a non-specific effect similar to a startle reflex and reduced RT substantially (15ms on average) with respect to a control condition without TMS (mean value=153ms). (2) Irrespective of TMS, RT were shorter when the right or the left hand was positioned in the right visual hemi-field (i.e. normal and crossed positions respectively). (3) Finally, RT increased when single pulse TMS was applied to the left parietal area and when hands were crossed irrespective of which hand was used. We concluded that interhemispheric sensori-motor remapping was disrupted by a single pulse TMS that was applied to the left parietal cortex. This effect was also combined with some visual attention directed towards the hand located on the right visual hemi-field.

  4. 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.

  5. PERSISTENT LEFT SUPERIOR VENACAVA

    Directory of Open Access Journals (Sweden)

    Devinder Singh

    2014-05-01

    Full Text Available A Persistent Left Superior Venacava (PLSVC is the most common variation of the thoracic venous system and rare congenital vascular anomaly and is prevalent in 0.3% of the population. It may be associated with other cardiovascular abnormalities including atrial septal defect, bicuspid aortic valve, coarctation of aorta, coronary sinus ostial atresia, and cor triatriatum. Incidental rotation of a dilated coronary sinus on echocardiography should raise the suspicion of PLSVC. The diagnosis should be confirmed by saline contrast echocardiography. Condition is usually asymptomatic. Here we present a rare case of persistent left superior vena cava presented in OPD with dyspnoea & palpitations.

  6. Superior memorizers employ different neural networks for encoding and recall.

    Science.gov (United States)

    Mallow, Johannes; Bernarding, Johannes; Luchtmann, Michael; Bethmann, Anja; Brechmann, André

    2015-01-01

    Superior memorizers often employ the method of loci (MoL) to memorize large amounts of information. The MoL, known since ancient times, relies on a complex process where information to be memorized is bound to landmarks along mental routes in a previously memorized environment. However, functional magnetic resonance imaging data on groups of trained superior memorizer are rare. Based on the memorizing strategy reported by superior memorizers, we developed a scheme of the processes successively employed during memorizing and recalling digits and relate these to brain activation that is specific for the encoding and recall period. In the examined superior memorizers several regions, suggested to be involved in mental navigation and digit-to-word processing, were specifically activated during encoding: bilateral early visual cortex, retrosplenial cortex, left parahippocampus, left visual cortex, and left superior parietal cortex. Although the scheme suggests that some steps during encoding and recall seem to be analog, none of the encoding areas were specifically activated during the recall. Instead, we found strong activation in left anterior superior temporal gyrus, which we relate to recalling the sequential order of the digits, and right motor cortex that may be related to reciting the digits.

  7. Superior Memorizers Employ Different Neural Networks for Encoding and Recall

    Directory of Open Access Journals (Sweden)

    Johannes eMallow

    2015-09-01

    Full Text Available Superior memorizers often employ the method of loci (MoL to memorize large amounts of information. The method of loci, known since ancient times, relies on a complex process where information to be memorized is bound to landmarks along mental routes in a previously memorized environment. However, fMRI data on groups of trained superior memorizer are rare. Based on the memorizing strategy reported by superior memorizers we developed a scheme of the processes successively employed during memorizing and recalling digits and relate these to brain activation that is specific for the encoding and recall period. In the examined superior memorizers several regions, suggested to be involved in mental navigation and digit-to-word processing, were specifically activated during encoding: bilateral early visual cortex, retrosplenial cortex, left parahippocampus, left visual cortex, and left superior parietal cortex. Although the scheme suggests that some steps during encoding and recall seem to be analog, none of the encoding areas were specifically activated during the recall. Instead, we found strong activation in left anterior superior temporal gyrus, which we relate to recalling the sequential order of the digits, and right motor cortex that may be related to reciting the digits.

  8. Cortical Lewy Body Dementia

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    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.

  9. Distinct contribution of the parietal and temporal cortex to hand configuration and contextual judgements about tools.

    Science.gov (United States)

    Andres, Michael; Pelgrims, Barbara; Olivier, Etienne

    2013-09-01

    Neuropsychological studies showed that manipulatory and semantic knowledge can be independently impaired in patients with upper-limb apraxia, leading to different tool use disorders. The present study aimed to dissociate the brain regions involved in judging the hand configuration or the context associated to tool use. We focussed on the left supramarginalis gyrus (SMG) and left middle temporal gyrus (MTG), whose activation, as evidenced by functional magnetic resonance imaging (fMRI) studies, suggests that they may play a critical role in tool use. The distinctive location of SMG in the dorsal visual stream led us to postulate that this parietal region could play a role in processing incoming information about tools to shape hand posture. In contrast, we hypothesized that MTG, because of its interconnections with several cortical areas involved in semantic memory, could contribute to retrieving semantic information necessary to create a contextual representation of tool use. To test these hypotheses, we used neuronavigated transcranial magnetic stimulation (TMS) to interfere transiently with the function of either left SMG or left MTG in healthy participants performing judgement tasks about either hand configuration or context of tool use. We found that SMG virtual lesions impaired hand configuration but not contextual judgements, whereas MTG lesions selectively interfered with judgements about the context of tool use while leaving hand configuration judgements unaffected. This double dissociation demonstrates that the ability to infer a context of use or a hand posture from tool perception relies on distinct processes, performed in the temporal and parietal regions. The present findings suggest that tool use disorders caused by SMG lesions will be characterized by difficulties in selecting the appropriate hand posture for tool use, whereas MTG lesions will yield difficulties in using tools in the appropriate context.

  10. Exploring the contributions of premotor and parietal cortex to spatial compatibility using image-guided TMS.

    Science.gov (United States)

    Koski, Lisa; Molnar-Szakacs, Istvan; Iacoboni, Marco

    2005-01-15

    Functional brain imaging studies have demonstrated increased activity in dorsal premotor and posterior parietal cortex when performing spatial stimulus-response compatibility tasks (SRC). We tested the specific role of these regions in stimulus-response mapping using single-pulse transcranial magnetic stimulation (TMS). Subjects were scanned using functional magnetic resonance imaging (fMRI) prior to the TMS session during performance of a task in which spatial compatibility was manipulated. For each subject, the area of increased signal within the regions of interest was registered onto their own high-resolution T1-weighted anatomic scan. TMS was applied to these areas for each subject using a frameless stereotaxic system. Task accuracy and reaction time (RT) were measured during blocks of compatible or incompatible trials and during blocks of real TMS or sham stimulation. On each trial, a single TMS pulse was delivered at 50, 100, 150, or 200 ms after the onset of the stimulus in the left or right visual field. TMS over the left premotor cortex produced various facilitatory effects, depending on the timing of the stimulation. At short intervals, TMS appeared to prime the left dorsal premotor cortex to select a right-hand response more quickly, regardless of stimulus-response compatibility. The strongest effect of stimulation, however, occurred at the 200-ms interval, when TMS facilitated left-hand responses during the incompatible condition. Facilitation of attention to the contralateral visual hemifield was observed during stimulation over the parietal locations. We conclude that the left premotor cortex is one of the cortical regions responsible for overriding automatic stimulus-response associations.

  11. Frontal lobe and posterior parietal contributions to the cortico-cerebellar system.

    Science.gov (United States)

    Ramnani, Narender

    2012-06-01

    Our growing understanding of how cerebral cortical areas communicate with the cerebellum in primates has enriched our understanding of the data that cerebellar circuits can access, and the neocortical areas that cerebellar activity can influence. The cerebellum is part of some large-scale networks involving several parts of the neocortex including association areas in the frontal lobe and the posterior parietal cortex that are known for their contributions to higher cognitive function. Understanding their connections with the cerebellum informs the debates around the role of the cerebellum in higher cognitive functions because they provide mechanisms through which association areas and the cerebellum can influence each others' operations. In recent years, evidence from connectional anatomy and human neuroimaging have comprehensively overturned the view that the cerebellum contributes only to motor control. The aim of this review is to examine our changing perspectives on the nature of cortico-cerebellar anatomy and the ways in which it continues to shape our views on its contributions to function. The review considers the anatomical connectivity of the cerebellar cortex with frontal lobe areas and the posterior parietal cortex. It will first focus on the anatomical organisation of these circuits in non-human primates before discussing new findings about this system in the human brain. It has been suggested that in non-human primates "although there is a modest input from medial prefrontal cortex, there is very little or none from the more lateral prefrontal areas" [33]. This review discusses anatomical investigations that challenge this claim. It also attempts to dispel the misconception that prefrontal projections to the cerebellum are from areas concerned only with the kinematic control of eye movements. Finally, I argue that our revised understanding of anatomy compels us to reconsider conventional views of how these systems operate in the human brain.

  12. Replenishment of the podocyte compartment by parietal epithelial cells.

    Science.gov (United States)

    Kopp, Jeffrey B

    2015-11-01

    While progressive podocytopenia is a characteristic feature of chronic glomerular disease, the visceral epithelial niche can be replenished from the parietal epithelium. Two new reports demonstrate this process in genetically engineered mice, using fate mapping, and in human renal biopsies manifesting segmental glomerulosclerosis in diverse settings, using cellular and extracellular matrix markers.

  13. Left inferior parietal lobe engagement in social cognition and language.

    Science.gov (United States)

    Bzdok, Danilo; Hartwigsen, Gesa; Reid, Andrew; Laird, Angela R; Fox, Peter T; Eickhoff, Simon B

    2016-09-01

    Social cognition and language are two core features of the human species. Despite distributed recruitment of brain regions in each mental capacity, the left parietal lobe (LPL) represents a zone of topographical convergence. The present study quantitatively summarizes hundreds of neuroimaging studies on social cognition and language. Using connectivity-based parcellation on a meta-analytically defined volume of interest (VOI), regional coactivation patterns within this VOI allowed identifying distinct subregions. Across parcellation solutions, two clusters emerged consistently in rostro-ventral and caudo-ventral aspects of the parietal VOI. Both clusters were functionally significantly associated with social-cognitive and language processing. In particular, the rostro-ventral cluster was associated with lower-level processing facets, while the caudo-ventral cluster was associated with higher-level processing facets in both mental capacities. Contrarily, in the (less stable) dorsal parietal VOI, all clusters reflected computation of general-purpose processes, such as working memory and matching tasks, that are frequently co-recruited by social or language processes. Our results hence favour a rostro-caudal distinction of lower- versus higher-level processes underlying social cognition and language in the left inferior parietal lobe. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Left inferior parietal lobe engagement in social cognition and language

    NARCIS (Netherlands)

    Bzdok, D.; Hartwigsen, G.; Reid, A.T.; Laird, A.R.; Fox, P.T.; Eickhoff, S.B.

    2016-01-01

    Social cognition and language are two core features of the human species. Despite distributed recruitment of brain regions in each mental capacity, the left parietal lobe (LPL) represents a zone of topographical convergence. This study quantitatively summarizes previous neuroimaging studies on

  15. Parietal cortex mediates perceptual Gestalt grouping independent of stimulus size.

    Science.gov (United States)

    Grassi, Pablo R; Zaretskaya, Natalia; Bartels, Andreas

    2016-06-01

    The integration of local moving elements into a unified gestalt percept has previously been linked to the posterior parietal cortex. There are two possible interpretations for the lack of involvement of other occipital regions. The first is that parietal cortex is indeed uniquely functionally specialized to perform grouping. Another possibility is that other visual regions can perform grouping as well, but that the large spatial separation of the local elements used previously exceeded their neurons' receptive field (RF) sizes, preventing their involvement. In this study we distinguished between these two alternatives. We measured whole-brain activity using fMRI in response to a bistable motion illusion that induced mutually exclusive percepts of either an illusory global Gestalt or of local elements. The stimulus was presented in two sizes, a large version known to activate IPS only, and a version sufficiently small to fit into the RFs of mid-level dorsal regions such as V5/MT. We found that none of the separately localized motion regions apart from parietal cortex showed a preference for global Gestalt perception, even for the smaller version of the stimulus. This outcome suggests that grouping-by-motion is mediated by a specialized size-invariant mechanism with parietal cortex as its anatomical substrate. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Directed cortical information flow during human object recognition: analyzing induced EEG gamma-band responses in brain's source space.

    Directory of Open Access Journals (Sweden)

    Gernot G Supp

    Full Text Available The increase of induced gamma-band responses (iGBRs; oscillations >30 Hz elicited by familiar (meaningful objects is well established in electroencephalogram (EEG research. This frequency-specific change at distinct locations is thought to indicate the dynamic formation of local neuronal assemblies during the activation of cortical object representations. As analytically power increase is just a property of a single location, phase-synchrony was introduced to investigate the formation of large-scale networks between spatially distant brain sites. However, classical phase-synchrony reveals symmetric, pair-wise correlations and is not suited to uncover the directionality of interactions. Here, we investigated the neural mechanism of visual object processing by means of directional coupling analysis going beyond recording sites, but rather assessing the directionality of oscillatory interactions between brain areas directly. This study is the first to identify the directionality of oscillatory brain interactions in source space during human object recognition and suggests that familiar, but not unfamiliar, objects engage widespread reciprocal information flow. Directionality of cortical information-flow was calculated based upon an established Granger-Causality coupling-measure (partial-directed coherence; PDC using autoregressive modeling. To enable comparison with previous coupling studies lacking directional information, phase-locking analysis was applied, using wavelet-based signal decompositions. Both, autoregressive modeling and wavelet analysis, revealed an augmentation of iGBRs during the presentation of familiar objects relative to unfamiliar controls, which was localized to inferior-temporal, superior-parietal and frontal brain areas by means of distributed source reconstruction. The multivariate analysis of PDC evaluated each possible direction of brain interaction and revealed widespread reciprocal information-transfer during familiar

  17. 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

  18. 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

  19. Functional connectivity of parietal cortex during temporal selective attention.

    Science.gov (United States)

    Tyler, Sarah C; Dasgupta, Samhita; Agosta, Sara; Battelli, Lorella; Grossman, Emily D

    2015-04-01

    Perception of natural experiences requires allocation of attention towards features, objects, and events that are moving and changing over time. This allocation of attention is controlled by large-scale brain networks that, when damaged, cause widespread cognitive deficits. In particular, damage to ventral parietal cortex (right lateralized TPJ, STS, supramarginal and angular gyri) is associated with failures to selectively attend to and isolate features embedded within rapidly changing visual sequences (Battelli, Pascual-Leone, & Cavanagh, 2007; Husain, Shapiro, Martin, & Kennard, 1997). In this study, we used fMRI to investigate the neural activity and functional connectivity of intact parietal cortex while typical subjects judged the relative onsets and offsets of rapidly flickering tokens (a phase discrimination task in which right parietal patients are impaired). We found two regions in parietal cortex correlated with task performance: a bilateral posterior TPJ (pTPJ) and an anterior right-lateralized TPJ (R aTPJ). Both regions were deactivated when subjects engaged in the task but showed different patterns of functional connectivity. The bilateral pTPJ was strongly connected to nodes within the default mode network (DMN) and the R aTPJ was connected to the attention network. Accurate phase discriminations were associated with increased functional correlations between sensory cortex (hMT+) and the bilateral pTPJ, whereas accuracy on a control task was associated with yoked activity in the hMT+ and the R aTPJ. We conclude that temporal selective attention is particularly sensitive for revealing information pathways between sensory and core cognitive control networks that, when damaged, can lead to nonspatial attention impairments in right parietal stroke patients.

  20. Multiple parietal-frontal pathways mediate grasping in macaque monkeys

    Science.gov (United States)

    Gharbawie, Omar A.; Stepniewska, Iwona; Qi, Huixin; Kaas, Jon H.

    2011-01-01

    The nodes of a parietal-frontal pathway that mediates grasping in primates are in anterior intraparietal area (AIP) and ventral premotor cortex (PMv). Nevertheless, multiple somatosensory and motor representations of the hand, respectively in parietal and frontal cortex, suggest that additional pathways remain unrealized. We explored this possibility in macaque monkeys by injecting retrograde tracers into grasp zones identified in M1, PMv, and area 2 with long train electrical stimulation. The M1 grasp zone was densely connected with other frontal cortex motor regions. The remainder of the connections originated from somatosensory areas 3a and S2/PV, and from the medial bank and fundus of the intraparietal sulcus (IPS). The PMv grasp zone was also densely connected with frontal cortex motor regions, albeit to a lesser extent than the M1 grasp zone. The remainder of the connections originated from areas S2/PV and aspects of the inferior parietal lobe such as PF, PFG, AIP, and the tip of the IPS. The area 2 grasp zone was densely connected with the hand representations of somatosensory areas 3b, 1, and S2/PV. The remainder of the connections was with areas 3a and 5 and the medial bank and fundus of the IPS. Connections with frontal cortex were relatively weak and concentrated in caudal M1. Thus, the three grasp zones may be nodes of parallel parietal-frontal pathways. Differential points of origin and termination of each pathway suggest varying functional specializations. Direct and indirect connections between those parietal-frontal pathways likely coordinate their respective functions into an accurate grasp. PMID:21832196

  1. 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.

  2. Multilevel cortical processing of somatosensory novelty: a magnetoencephalography study

    Directory of Open Access Journals (Sweden)

    Gilles eNaeije

    2016-06-01

    Full Text Available Using magnetoencephalography (MEG, this study investigates the spatio-temporal dynamics of the multilevel cortical processing of somatosensory change detection. Neuromagnetic signals of sixteen healthy adult subjects (7 females and 9 males, mean age 29 +/-3 y were recorded using whole-scalp-covering MEG while they underwent an oddball paradigm based on simple standard (right index fingertip tactile stimulation and deviant (simultaneous right index fingertip and middle phalanx tactile stimulation stimuli gathered into sequences to create and then deviate from stimulus patterns at multiple (local versus global levels of complexity. Five healthy adult subjects (3 females and 2 males, mean age 31,6 +/-2 y also underwent a similar oddball paradigm in which standard and deviant stimuli were flipped.Local deviations led to a somatosensory mismatch response peaking at 55-130 ms post-stimulus onset with a cortical generator located at the contralateral secondary somatosensory cortex. The mismatch response was independent of the deviant stimuli physical characteristics. Global deviants led to a P300 response with cortical sources located bilaterally at temporo-parietal junction (TPJ and supplementary motor area (SMA. The posterior parietal cortex (PPC and the SMA were found to generate a contingent magnetic variation (CMV attributed to top-down expectations. Amplitude of mismatch responses were modulated by top-down expectations and correlated with both the magnitude of the CMV and the P300 amplitude at the right TPJ. These results provide novel empirical evidence for a unified sensory novelty detection system in the human brain by linking detection of salient sensory stimuli in personal and extra-personal spaces to a common framework of multilevel cortical processing.

  3. Effect of visual feedback on the occipito-parietal-motor network in Parkinson's disease patients with freezing of gait

    Directory of Open Access Journals (Sweden)

    Priya D Velu

    2014-01-01

    Full Text Available Freezing of gait (FOG is an elusive phenomenon that debilitates a large number of Parkinson’s disease (PD patients regardless of stage of disease, medication status, or DBS implantation. Sensory cues, especially visual feedback cues, have been shown to alleviate FOG episodes or prevent episodes from even occurring. Here, we examine cortical information flow between occipital, parietal, and motor areas during the pre-movement stage of gait in a PD-with-FOG patient that had a strong positive behavioral response to visual cues, a PD-with-FOG patient without any behavioral response to visual cues, and an age-matched healthy control, before and after training with visual feedback. Results for this case study show differences in cortical information flow between the responding PD-with-FOG patient and the other two subjects, notably, an increased information flow in the beta range. Tentatively suggesting the formation of an alternative cortical sensory-motor pathway during training with visual feedback, these results are proposed as subject for further verification employing larger cohorts of patients.

  4. [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.

  5. Pain modulation in waking and hypnosis in women: event-related potentials and sources of cortical activity.

    Science.gov (United States)

    De Pascalis, Vilfredo; Varriale, Vincenzo; Cacace, Immacolata

    2015-01-01

    Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N

  6. Pain modulation in waking and hypnosis in women: event-related potentials and sources of cortical activity.

    Directory of Open Access Journals (Sweden)

    Vilfredo De Pascalis

    Full Text Available Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA method revealed significant activations of the bilateral primary somatosensory (BA3, middle frontal gyrus (BA6 and anterior cingulate cortices (BA24. Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32, while for the P200 wave, activity was increased in the superior (BA22, middle (BA37, inferior temporal (BA19 gyri and superior parietal lobule (BA7. Hypnotic hypoalgesia in

  7. Regional quantitative analysis of cortical surface maps of FDG PET images

    CERN Document Server

    Protas, H D; Hayashi, K M; Chin Lung, Yu; Bergsneider, M; Sung Cheng, Huang

    2006-01-01

    Cortical surface maps are advantageous for visualizing the 3D profile of cortical gray matter development and atrophy, and for integrating structural and functional images. In addition, cortical surface maps for PET data, when analyzed in conjunction with structural MRI data allow us to investigate, and correct for, partial volume effects. Here we compared quantitative regional PET values based on a 3D cortical surface modeling approach with values obtained directly from the 3D FDG PET images in various atlas-defined regions of interest (ROIs; temporal, parietal, frontal, and occipital lobes). FDG PET and 3D MR (SPGR) images were obtained and aligned to ICBM space for 15 normal subjects. Each image was further elastically warped in 2D parameter space of the cortical surface, to align major cortical sulci. For each point within a 15 mm distance of the cortex, the value of the PET intensity was averaged to give a cortical surface map of FDG uptake. The average PET values on the cortical surface map were calcula...

  8. Imaging cortical activity following affective stimulation with a high temporal and spatial resolution

    Directory of Open Access Journals (Sweden)

    Catani Claudia

    2009-07-01

    Full Text Available Abstract Background The affective and motivational relevance of a stimulus has a distinct impact on cortical processing, particularly in sensory areas. However, the spatial and temporal dynamics of this affective modulation of brain activities remains unclear. The purpose of the present study was the development of a paradigm to investigate the affective modulation of cortical networks with a high temporal and spatial resolution. We assessed cortical activity with MEG using a visual steady-state paradigm with affective pictures. A combination of a complex demodulation procedure with a minimum norm estimation was applied to assess the temporal variation of the topography of cortical activity. Results Statistical permutation analyses of the results of the complex demodulation procedure revealed increased steady-state visual evoked field amplitudes over occipital areas following presentation of affective pictures compared to neutral pictures. This differentiation shifted in the time course from occipital regions to parietal and temporal regions. Conclusion It can be shown that stimulation with affective pictures leads to an enhanced activity in occipital region as compared to neutral pictures. However, the focus of differentiation is not stable over time but shifts into temporal and parietal regions within four seconds of stimulation. Thus, it can be crucial to carefully choose regions of interests and time intervals when analyzing the affective modulation of cortical activity.

  9. 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...

  10. Pronounced Impairment of Everyday Skills and Self-Care in Posterior Cortical Atrophy.

    OpenAIRE

    Shakespeare, T. J.; Yong, K. X.; Foxe, D.; Hodges, J.; Crutch, S. J.

    2014-01-01

    Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by progressive visual dysfunction and parietal, occipital, and occipitotemporal atrophy. The aim of this study was to compare the impact of PCA and typical Alzheimer's disease (tAD) on everyday functional abilities and neuropsychiatric status. The Cambridge Behavioural Inventory-Revised was given to carers of 32 PCA and 71 tAD patients. PCA patients showed significantly greater impairment in everyday skills and sel...

  11. Cortical sources of ERP in prosaccade and antisaccade eye movements using realistic source models

    Science.gov (United States)

    Richards, John E.

    2013-01-01

    The cortical sources of event-related-potentials (ERP) using realistic source models were examined in a prosaccade and antisaccade procedure. College-age participants were presented with a preparatory interval and a target that indicated the direction of the eye movement that was to be made. In some blocks a cue was given in the peripheral location where the target was to be presented and in other blocks no cue was given. In Experiment 1 the prosaccade and antisaccade trials were presented randomly within a block; in Experiment 2 procedures were compared in which either prosaccade and antisaccade trials were mixed in the same block, or trials were presented in separate blocks with only one type of eye movement. There was a central negative slow wave occurring prior to the target, a slow positive wave over the parietal scalp prior to the saccade, and a parietal spike potential immediately prior to saccade onset. Cortical source analysis of these ERP components showed a common set of sources in the ventral anterior cingulate and orbital frontal gyrus for the presaccadic positive slow wave and the spike potential. In Experiment 2 the same cued- and non-cued blocks were used, but prosaccade and antisaccade trials were presented in separate blocks. This resulted in a smaller difference in reaction time between prosaccade and antisaccade trials. Unlike the first experiment, the central negative slow wave was larger on antisaccade than on prosaccade trials, and this effect on the ERP component had its cortical source primarily in the parietal and mid-central cortical areas contralateral to the direction of the eye movement. These results suggest that blocked prosaccade and antisaccade trials results in preparatory or set effects that decreases reaction time, eliminates some cueing effects, and is based on contralateral parietal-central brain areas. PMID:23847476

  12. Cortical Sources of ERP in Prosaccade and Antisaccade Eye Movements using Realistic Source Models

    Directory of Open Access Journals (Sweden)

    John E Richards

    2013-07-01

    Full Text Available The cortical sources of event-related-potentials (ERP using realistic source models were examined in a prosaccade and antisaccade task. College-age participants were presented with a preparatory interval and a target that indicated the direction of the eye movement that was to be made. In some blocks a cue was given in the peripheral location where the target was to be presented and in other blocks no cue was given. In Experiment 1 the prosaccade and antisaccade trials were presented randomly within a block; in Experiment 2 procedures were compared in which either prosaccade and antisaccade trials were mixed in the same block, or trials were presented in separate blocks with only one type of eye movement. There was a central negative slow wave occurring prior to the target, a slow positive wave over the parietal scalp prior to the saccade, and a parietal spike potential immediately prior to saccade onset. Cortical source analysis of these ERP components showed a common set of sources in the ventral anterior cingulate and orbital frontal gyrus for the presaccadic positive slow wave and the spike potential. In Experiment 2 the same cued- and non-cued blocks were used, but prosaccade and antisaccade trials were presented in separate blocks. This resulted in a smaller difference in reaction time between prosaccade and antisaccade trials. Unlike the first experiment, the central negative slow wave was larger on antisaccade than on prosaccade trials, and this effect on the ERP component had its cortical source primarily in the parietal and mid-central cortical areas contralateral to the direction of the eye movement. These results suggest that blocked prosaccade and antisaccade trials results in preparatory or set effects that decreases reaction time, eliminates some cueing effects, and is based on contralateral parietal-central brain areas.

  13. Air Superiority Fighter Characteristics.

    Science.gov (United States)

    1998-06-05

    many a dispute could have been deflated into a single paragraph if the disputants had just dared to define their terms.7 Aristotle ...meaningful. This section will expand on some key ideology concepts. The phrase "air superiority fighter" may bring to mind visions of fighter... biographies are useful in garnering airpower advocate theories as well as identifying key characteristics. Air campaign results, starting with World

  14. Individual differences in left parietal white matter predict math scores on the Preliminary Scholastic Aptitude Test.

    Science.gov (United States)

    Matejko, Anna A; Price, Gavin R; Mazzocco, Michèle M M; Ansari, Daniel

    2013-02-01

    Mathematical skills are of critical importance, both academically and in everyday life. Neuroimaging research has primarily focused on the relationship between mathematical skills and functional brain activity. Comparatively few studies have examined which white matter regions support mathematical abilities. The current study uses diffusion tensor imaging (DTI) to test whether individual differences in white matter predict performance on the math subtest of the Preliminary Scholastic Aptitude Test (PSAT). Grades 10 and 11 PSAT scores were obtained from 30 young adults (ages 17-18) with wide-ranging math achievement levels. Tract based spatial statistics was used to examine the correlation between PSAT math scores, fractional anisotropy (FA), radial diffusivity (RD) and axial diffusivity (AD). FA in left parietal white matter was positively correlated with math PSAT scores (specifically in the left superior longitudinal fasciculus, left superior corona radiata, and left corticospinal tract) after controlling for chronological age and same grade PSAT critical reading scores. Furthermore, RD, but not AD, was correlated with PSAT math scores in these white matter microstructures. The negative correlation with RD further suggests that participants with higher PSAT math scores have greater white matter integrity in this region. Individual differences in FA and RD may reflect variability in experience dependent plasticity over the course of learning and development. These results are the first to demonstrate that individual differences in white matter are associated with mathematical abilities on a nationally administered scholastic aptitude measure.

  15. Functional topography of the right inferior parietal lobule structured by anatomical connectivity profiles.

    Science.gov (United States)

    Wang, Jiaojian; Zhang, Jinfeng; Rong, Menglin; Wei, Xuehu; Zheng, Dingchen; Fox, Peter T; Eickhoff, Simon B; Jiang, Tianzi

    2016-12-01

    The nature of the relationship between structure and function is a fundamental question in neuroscience, especially at the macroscopic neuroimaging level. Although mounting studies have revealed that functional connectivity reflects structural connectivity, whether similar structural and functional connectivity patterns can reveal corresponding similarities in the structural and functional topography remains an open problem. In our current study, we used the right inferior parietal lobule (RIPL), which has been demonstrated to have similar anatomical and functional connectivity patterns at the subregional level, to directly test the hypothesis that similar structural and functional connectivity patterns can inform the corresponding topography of this area. In addition, since the association between the RIPL regions and particular functions and networks is still largely unknown, post-hoc functional characterizations and connectivity analyses were performed to identify the main functions and cortical networks in which each subregion participated. Anatomical and functional connectivity-based parcellations of the RIPL have consistently identified five subregions. Our functional characterization using meta-analysis-based behavioral and connectivity analyses revealed that the two anterior subregions (Cl1 and Cl2) primarily participate in interoception and execution, respectively; whereas the posterior subregion (Cl3) in the SMG primarily participates in attention and action inhibition. The two posterior subregions (Cl4, Cl5) in the AG were primarily involved in social cognition and spatial cognition, respectively. These results indicated that similar anatomical and functional connectivity patterns of the RIPL are reflected in corresponding structural and functional topographies. The identified cortical connectivity and functional characterization of each subregion may facilitate RIPL-related clinical research. Hum Brain Mapp 37:4316-4332, 2016. © 2016 Wiley Periodicals

  16. Reduced cortical thickness associated with visceral fat and BMI

    Directory of Open Access Journals (Sweden)

    Ralf Veit

    2014-01-01

    Full Text Available Structural brain imaging studies have shown that obesity is associated with widespread reductions in gray matter (GM volume. Although the body mass index (BMI is an easily accessible anthropometric measure, substantial health problems are more related to specific body fat compartments, like visceral adipose tissue (VAT. We investigated cortical thickness measures in a group of 72 healthy subjects (BMI range 20–35 kg/m2, age range 19–50 years. Multiple regression analyses were performed using VAT and BMI as predictors and age, gender, total surface area and education as confounds. BMI and VAT were independently associated with reductions in cortical thickness in clusters comprising the left lateral occipital area, the left inferior temporal cortex, and the left precentral and inferior parietal area, while the right insula, the left fusiform gyrus and the right inferior temporal area showed a negative correlation with VAT only. In addition, we could show significant reductions in cortical thickness with increasing VAT adjusted for BMI in the left temporal cortex. We were able to detect widespread cortical thinning in a young to middle-aged population related to BMI and VAT; these findings show close resemblance to studies focusing on GM volume differences in diabetic patients. This may point to the influence of VAT related adverse effects, like low-grade inflammation, as a potentially harmful factor on brain integrity already in individuals at risk of developing diabetes, metabolic syndromes and arteriosclerosis.

  17. 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

  18. Amyloid-β Associated Cortical Thinning in Clinically Normal Elderly

    Science.gov (United States)

    Becker, J Alex; Hedden, Trey; Carmasin, Jeremy; Maye, Jacqueline; Rentz, Dorene M; Putcha, Deepti; Fischl, Bruce; Greve, Douglas N; Marshall, Gad A; Salloway, Stephen; Marks, Donald; Buckner, Randy L; Sperling, Reisa A; Johnson, Keith A

    2011-01-01

    Objective Both amyloid-β (Aβ) deposition and brain atrophy are associated with Alzheimer's disease (AD) and the disease process likely begins many years before symptoms appear. We sought to determine whether clinically normal (CN) older individuals with Aβ deposition revealed by positron emission tomography (PET) imaging using Pittsburgh Compound B (PiB) also have evidence of both cortical thickness and hippocampal volume reductions in a pattern similar to that seen in AD. Methods A total of 119 older individuals (87 CN subjects and 32 patients with mild AD) underwent PiB PET and high-resolution structural magnetic resonance imaging (MRI). Regression models were used to relate PiB retention to cortical thickness and hippocampal volume. Results We found that PiB retention in CN subjects was (1) age-related and (2) associated with cortical thickness reductions, particularly in parietal and posterior cingulate regions extending into the precuneus, in a pattern similar to that observed in mild AD. Hippocampal volume reduction was variably related to Aβ deposition. Interpretation We conclude that Aβ deposition is associated with a pattern of cortical thickness reduction consistent with AD prior to the development of cognitive impairment. ANN NEUROL 2010; PMID:21437929

  19. Overlapping Parietal Activity in Memory and Perception: Evidence for the Attention to Memory Model

    Science.gov (United States)

    Cabeza, Roberto; Mazuz, Yonatan S.; Stokes, Jared; Kragel, James E.; Woldorff, Marty G.; Ciaramelli, Elisa; Olson, Ingrid R.; Moscovitch, Morris

    2011-01-01

    The specific role of different parietal regions to episodic retrieval is a topic of intense debate. According to the Attention to Memory (AtoM) model, dorsal parietal cortex (DPC) mediates top-down attention processes guided by retrieval goals, whereas ventral parietal cortex (VPC) mediates bottom-up attention processes captured by the retrieval…

  20. A case of secondary somatosensory epilepsy with a left deep parietal opercular lesion: successful tumor resection using a transsubcentral gyral approach during awake surgery.

    Science.gov (United States)

    Maesawa, Satoshi; Fujii, Masazumi; Futamura, Miyako; Hayashi, Yuichiro; Iijima, Kentaro; Wakabayashi, Toshihiko

    2016-03-01

    Few studies have examined the clinical characteristics of patients with lesions in the deep parietal operculum facing the sylvian fissure, the region recognized as the secondary somatosensory area (SII). Moreover, surgical approaches in this region are challenging. In this paper the authors report on a patient presenting with SII epilepsy with a tumor in the left deep parietal operculum. The patient was a 24-year-old man who suffered daily partial seizures with extremely uncomfortable dysesthesia and/or occasional pain on his right side. MRI revealed a tumor in the medial aspect of the anterior transverse parietal gyrus, surrounding the posterior insular point. Long-term video electroencephalography monitoring with scalp electrodes failed to show relevant changes to seizures. Resection with cortical and subcortical mapping under awake conditions was performed. A negative response to stimulation was observed at the subcentral gyrus during language and somatosensory tasks; thus, the transcortical approach (specifically, a transsubcentral gyral approach) was used through this region. Subcortical stimulation at the medial aspect of the anterior parietal gyrus and the posterior insula around the posterior insular point elicited strong dysesthesia and pain in his right side, similar to manifestation of his seizure. The tumor was completely removed and pathologically diagnosed as pleomorphic xanthoastrocytoma. His epilepsy disappeared without neurological deterioration postoperatively. In this case study, 3 points are clinically significant. First, the clinical manifestation of this case was quite rare, although still representative of SII epilepsy. Second, the location of the lesion made surgical removal challenging, and the transsubcentral gyral approach was useful when intraoperative mapping was performed during awake surgery. Third, intraoperative mapping demonstrated that the patient experienced pain with electrical stimulation around the posterior insular point

  1. From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing.

    Science.gov (United States)

    Schlaffke, Lara; Rüther, Naima N; Heba, Stefanie; Haag, Lauren M; Schultz, Thomas; Rosengarth, Katharina; Tegenthoff, Martin; Bellebaum, Christian; Schmidt-Wilcke, Tobias

    2015-11-01

    Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico-semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico-semantic analysis). Perceptual and lexico-semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico-semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico-semantic stimulus analysis. Importantly, the activation pattern remains task-related LOP and is thus the result of a decision process as to which LOP to engage in.

  2. EEG UPPER/LOW ALPHA FREQUENCY POWER RATIO RELATES TO TEMPORO-PARIETAL BRAIN ATROPHY AND MEMORY PERFORMANCES IN MILD COGNITIVE IMPAIRMENT

    Directory of Open Access Journals (Sweden)

    Davide Vito Moretti

    2013-10-01

    Full Text Available Objective: temporo-parietal cortex thinning is associated to mild cognitive impairment (MCI due to Alzheimer disease (AD. The increase of EEG upper/low alpha power ratio has been associated with AD-converter MCI subjects. We investigated the association of alpha3/alpha2 ratio with patterns of cortical thickness in MCI.Methods: 74 adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG recording and high resolution 3D magnetic resonance imaging (MRI. Alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. Three MCI groups were detected according to increasing tertile values of upper/low alpha power ratio . Difference of cortical thikness among the groups was estimated. Pearson’s r was used to assess the topography of the correlation between cortical thinning and memory impairment.Results: High upper/low alpha power ratio group had total cortical grey matter (CGM volume reduction of 471 mm2 than low upper/low alpha power ratio group (p

  3. A case of lipoma of parietal peritoneum causing abdominal pain.

    Science.gov (United States)

    Bang, Chang Seok; Kim, Yeon Soo; Baik, Gwang Ho; Han, Sang Hak

    2014-06-01

    Lipomas are common benign tumors of mature adipose tissue, enclosed by thin fibrous capsules. They can occur on any part of the body; however, peritoneal lipoma is extremely rare. We encountered a case of a 75-year-old man presenting with intermittent abdominal pain, who had undergone right hemicolectomy due to colon cancer. Abdominal computerized tomography showed a well-defined heterogenous fatty mass measuring 4.5 × 3.5 cm in size, suggesting fat necrosis located in the abdominal wall. Laparotomy showed a very large soft mass of peritoneum. Pathologically, the tumor was diagnosed as lipoma containing fat necrosis located in parietal peritoneum not fixed to any organs, but with small bowel adhesion. Due to its rare etiologic origin and obscure cause of development, we report on a case of lipoma of parietal peritoneum causing abdominal pain.

  4. Impaired speech repetition and left parietal lobe damage.

    Science.gov (United States)

    Fridriksson, Julius; Kjartansson, Olafur; Morgan, Paul S; Hjaltason, Haukur; Magnusdottir, Sigridur; Bonilha, Leonardo; Rorden, Christopher

    2010-08-18

    Patients with left hemisphere damage and concomitant aphasia usually have difficulty repeating others' speech. Although impaired speech repetition, the primary symptom of conduction aphasia, has been associated with involvement of the left arcuate fasciculus, its specific lesion correlate remains elusive. This research examined speech repetition among 45 stroke patients who underwent aphasia testing and MRI examination. Based on lesion-behavior mapping, the primary structural damage most closely associated with impaired speech repetition was found in the posterior portion of the left arcuate fasciculus. However, perfusion-weighted MRI revealed that tissue dysfunction, in the form of either frank damage or hypoperfusion, to the left inferior parietal lobe, rather than the underlying white matter, was associated with impaired speech repetition. This latter result suggests that integrity of the left inferior parietal lobe is important for speech repetition and, as importantly, highlights the importance of examining cerebral perfusion for the purpose of lesion-behavior mapping in acute stroke.

  5. El arte parietal, espejo de las sociedades paleolíticas

    Directory of Open Access Journals (Sweden)

    Georges SAUVET

    2009-12-01

    Full Text Available RESUMEN: El presente trabajo aboga por un estudio del arte parietal como instrumento del conocimiento de la geografía humana de las sociedades de cazadores y de la evolución de sus redes de alianza, durante el Paleolítico superior. Tomando como ejemplo el componente figurativo de este arte y un amplio corpus de 3981 figuras procedentes de 154 yacimientos franceses y españoles, se demuestra que las asociaciones entre especies animales diferentes obedecen a reglas simples y coherentes, que se dejan fácilmente exprimir por un modelo formal. El análisis de doce sub-conjuntos sincrónicos y diacrónicos evidencia la movilidad de las connexiones interregionales (por ejemplo el desarrollo del Solutrense cantábrico en relación con los centros peninsulares y con escaso contacto con el sudoeste francés, al contrario de la situación que prevalece durante el Magdaleniense medio-superior. Sin embargo conforta la idea que las variaciones regionales operan dentro de un sistema de pensamiento religioso relativamente estable. Una segunda fase del trabajo se propone describir la estructuración del arte parietal a un nivel mucho más fino, teniendo en cuenta la diversidad formal de cada figura y sus relaciones topológicas con las demás. Una larga base de datos está en curso de elaboración para su tratamiento con las técnicas de "extracción de conocimiento" (Knowledge Discovery in Databases. Unos resultados preliminares dejan esperar que una base de datos de este tipo servirá el objetivo y proporcionará une visión más precisa y segura de la historia de los pueblos paleolíticos, dado que la fuente del estilo propio de cada grupo debe buscarse en la construcción gráfica de paneles complejos.ABSTRACT: This paper pleads in favour of the study of parietal art as a means to investigate the human geography of palaeolithic hunter-gatherers in Europe and the evolution of their alliance networks. Taking the example of the figurative component of Rock

  6. Different cortical areas in man in organization of voluntary movements in extrapersonal space

    DEFF Research Database (Denmark)

    Roland, P E; Skinhøj, E; Lassen, N A

    1980-01-01

    CBF in the supplementary motor area (bilaterally), the convexity part of the premotor area (bilaterally), the primary sensorimotor hand and arm area (contralaterally), and in the superior and inferior parietal region (bilaterally). 3. During the maze test there were, in addition, bilateral focal increases of the blood...... in extrapersonal space only are associated with activation of the parietal regions. These areas are assumed to provide information to the motor programming neurons about the demanded direction of motion in extrapersonal space in relation to proprioceptive reference systems. 6. The increase of rCBF in the auditory...

  7. Activation in a frontoparietal cortical network underlies individual differences in the performance of an embedded figures task.

    Science.gov (United States)

    Walter, Elizabeth; Dassonville, Paul

    2011-01-01

    The Embedded Figures Test (EFT) requires observers to search for a simple geometric shape hidden inside a more complex figure. Surprisingly, performance in the EFT is negatively correlated with susceptibility to illusions of spatial orientation, such as the Roelofs effect. Using fMRI, we previously demonstrated that regions in parietal cortex are involved in the contextual processing associated with the Roelofs task. In the present study, we found that similar parietal regions (superior parietal cortex and precuneus) were more active during the EFT than during a simple matching task. Importantly, these parietal activations overlapped with regions found to be involved during contextual processing in the Roelofs illusion. Additional parietal and frontal areas, in the right hemisphere, showed strong correlations between brain activity and behavioral performance during the search task. We propose that the posterior parietal regions are necessary for processing contextual information across many different, but related visuospatial tasks, with additional parietal and frontal regions serving to coordinate this processing in participants proficient in the task.

  8. Activation in a frontoparietal cortical network underlies individual differences in the performance of an embedded figures task.

    Directory of Open Access Journals (Sweden)

    Elizabeth Walter

    Full Text Available The Embedded Figures Test (EFT requires observers to search for a simple geometric shape hidden inside a more complex figure. Surprisingly, performance in the EFT is negatively correlated with susceptibility to illusions of spatial orientation, such as the Roelofs effect. Using fMRI, we previously demonstrated that regions in parietal cortex are involved in the contextual processing associated with the Roelofs task. In the present study, we found that similar parietal regions (superior parietal cortex and precuneus were more active during the EFT than during a simple matching task. Importantly, these parietal activations overlapped with regions found to be involved during contextual processing in the Roelofs illusion. Additional parietal and frontal areas, in the right hemisphere, showed strong correlations between brain activity and behavioral performance during the search task. We propose that the posterior parietal regions are necessary for processing contextual information across many different, but related visuospatial tasks, with additional parietal and frontal regions serving to coordinate this processing in participants proficient in the task.

  9. Importance of human right inferior frontoparietal network connected by inferior branch of superior longitudinal fasciculus tract in corporeal awareness of kinesthetic illusory movement.

    Science.gov (United States)

    Amemiya, Kaoru; Naito, Eiichi

    2016-05-01

    It is generally believed that the human right cerebral hemisphere plays a dominant role in corporeal awareness, which is highly associated with conscious experience of the physical self. Prompted by our previous findings, we examined whether the right frontoparietal activations often observed when people experience kinesthetic illusory limb movement are supported by a large-scale brain network connected by a specific branch of the superior longitudinal fasciculus fiber tracts (SLF I, II, and III). We scanned brain activity with functional magnetic resonance imaging (MRI) while nineteen blindfolded healthy volunteers experienced illusory movement of the right stationary hand elicited by tendon vibration, which was replicated after the scanning. We also scanned brain activity when they executed and imagined right hand movement, and identified the active brain regions during illusion, execution, and imagery in relation to the SLF fiber tracts. We found that illusion predominantly activated the right inferior frontoparietal regions connected by SLF III, which were not substantially recruited during execution and imagery. Among these regions, activities in the right inferior parietal cortices and inferior frontal cortices showed right-side dominance and correlated well with the amount of illusion (kinesthetic illusory awareness) experienced by the participants. The results illustrated the predominant involvement of the right inferior frontoparietal network connected by SLF III when people recognize postural changes of their limb. We assume that the network bears a series of functions, specifically, monitoring the current status of the musculoskeletal system, and building-up and updating our postural model (body schema), which could be a basis for the conscious experience of the physical self.

  10. Trans-saccadic interactions in human parietal and occipital cortex during the retention and comparison of object orientation.

    Science.gov (United States)

    Dunkley, Benjamin T; Baltaretu, Bianca; Crawford, J Douglas

    2016-09-01

    The cortical sites for the trans-saccadic storage and integration of visual object features are unknown. Here, we used a variant of fMRI-Adaptation where subjects fixated to the left or right of a briefly presented visual grating, maintained fixation or saccaded to the opposite side, then judged whether a re-presented grating had the same or different orientation. fMRI analysis revealed trans-saccadic interactions (different > same orientation) in a visual field-insensitive cluster within right supramarginal gyrus. This cluster was located at the anterolateral pole of the parietal eye field (identified in a localizer task). We also observed gaze centered, field-specific interactions (same > different orientation) in an extrastriate cluster overlapping with putative 'V4'. Based on these data and our literature review, we conclude that these supramarginal and extrastriate areas are involved in the retention, spatial updating, and evaluation of object orientation information across saccades.

  11. [Structural organization of the fronto-parietal area of the sensory-motor cortex of the rat brain].

    Science.gov (United States)

    Kakabadze, I M; Kostenko, N A

    1990-01-01

    Organizational peculiarities of the frontal-parietal area of the sensomotor cortex are: parvicellularity, alveolar-like distribution of neurons, radial striation of the lower zone, distinctly manifested stratification of the higher zone in the cortical plate, the middle zones contain short axonal pyramidal, stellate and granular neurons. Formation of somato-somatic contacts is specific for interneuronal interaction. Peculiarity of the normal ultrastructure of the neuronal cytoplasm is presence of 2-4 subsuperficial cisterns in the section. In neuropil, which is presented mainly as axo-spinal assymetrical contacts of the I type after Grey, transversal profiles of tightly arranged and collected in fasciculi finest axonal collaterals and terminal dendritic ramifications are revealed.

  12. Uniting functional network topology and oscillations in the fronto-parietal single unit network of behaving primates.

    Science.gov (United States)

    Dann, Benjamin; Michaels, Jonathan A; Schaffelhofer, Stefan; Scherberger, Hansjörg

    2016-08-15

    The functional communication of neurons in cortical networks underlies higher cognitive processes. Yet, little is known about the organization of the single neuron network or its relationship to the synchronization processes that are essential for its formation. Here, we show that the functional single neuron network of three fronto-parietal areas during active behavior of macaque monkeys is highly complex. The network was closely connected (small-world) and consisted of functional modules spanning these areas. Surprisingly, the importance of different neurons to the network was highly heterogeneous with a small number of neurons contributing strongly to the network function (hubs), which were in turn strongly inter-connected (rich-club). Examination of the network synchronization revealed that the identified rich-club consisted of neurons that were synchronized in the beta or low frequency range, whereas other neurons were mostly non-oscillatory synchronized. Therefore, oscillatory synchrony may be a central communication mechanism for highly organized functional spiking networks.

  13. 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.)

  14. Contabilidad Financiera Superior

    OpenAIRE

    Ipiñazar Petralanda, Izaskun

    2013-01-01

    Duración (en horas): De 31 a 40 horas. Destinatario: Estudiante y Docente A través de este material se presentan las pautas necesarias para implementar un aprendizaje basado en problemas en la asignatura de Contabilidad Financiera Superior dentro de los temas “Constitución de S.A. y S.R.L.” (Tema 2), “Ampliaciones de Capital” (Tema 3) y “Reducciones de Capital” (Tema 4). En primer lugar se presentan las guías generales de la asignatura, y a continuación, las diferentes activida...

  15. Contabilidad Financiera Superior

    OpenAIRE

    Ipiñazar Petralanda, Izaskun

    2013-01-01

    Duración (en horas): De 31 a 40 horas. Destinatario: Estudiante y Docente A través de este material se presentan las pautas necesarias para implementar un aprendizaje basado en problemas en la asignatura de Contabilidad Financiera Superior dentro de los temas “Constitución de S.A. y S.R.L.” (Tema 2), “Ampliaciones de Capital” (Tema 3) y “Reducciones de Capital” (Tema 4). En primer lugar se presentan las guías generales de la asignatura, y a continuación, las diferentes activida...

  16. Bottom-up Visual Integration in the Medial Parietal Lobe.

    Science.gov (United States)

    Pflugshaupt, Tobias; Nösberger, Myriam; Gutbrod, Klemens; Weber, Konrad P; Linnebank, Michael; Brugger, Peter

    2016-03-01

    Largely based on findings from functional neuroimaging studies, the medial parietal lobe is known to contribute to internally directed cognitive processes such as visual imagery or episodic memory. Here, we present 2 patients with behavioral impairments that extend this view. Both had chronic unilateral lesions of nearly the entire medial parietal lobe, but in opposite hemispheres. Routine neuropsychological examination conducted >4 years after the onset of brain damage showed little deficits of minor severity. In contrast, both patients reported persistent unusual visual impairment. A comprehensive series of tachistoscopic experiments with lateralized stimulus presentation and comparison with healthy participants revealed partial visual hemiagnosia for stimuli presented to their contralesional hemifield, applying inferential single-case statistics to evaluate deficits and dissociations. Double dissociations were found in 4 experiments during which participants had to integrate more than one visual element, either through comparison or formation of a global gestalt. Against the background of recent neuroimaging findings, we conclude that of all medial parietal structures, the precuneus is the most likely candidate for a crucial involvement in such bottom-up visual integration. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  17. Gestalt perception is associated with reduced parietal beta oscillations.

    Science.gov (United States)

    Zaretskaya, Natalia; Bartels, Andreas

    2015-05-15

    The ability to perceive composite objects as a whole is fundamental for visual perception in a complex and cluttered natural environment. This ability may be mediated by increased communication between neural representations of distinct object elements, and has been linked to increased synchronization of oscillatory brain activity in the gamma band. Previous studies of perceptual grouping either guided attention between local and global aspects of a given stimulus or manipulated its physical properties to achieve grouped and ungrouped perceptual conditions. In contrast to those studies, we fully matched the physical properties underlying global and local percepts using a bistable stimulus that causes the viewer to perceive either local motion of multiple elements or global motion of two illusory shapes without any external change. To test the synchronization hypothesis we recorded brain activity with EEG, while human participants viewed the stimulus and reported changes in their perception. In contrast to previous findings we show that power of the beta-band was lower during perception of global Gestalt than during that of local elements. Source localization places these differences in the posterior parietal cortex, overlapping with a site previously associated with both attention and Gestalt perception. These findings reveal a role of parietal beta-band activity in internally, rather than externally or attention-driven processes of Gestalt perception. They also add to the growing evidence for shared neural substrates of attention and Gestalt perception, both being linked to parietal cortex. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Commonalities for numerical and continuous quantity skills at temporo-parietal junction.

    Science.gov (United States)

    Cappelletti, Marinella; Chamberlain, Rebecca; Freeman, Elliot D; Kanai, Ryota; Butterworth, Brian; Price, Cathy J; Rees, Geraint

    2014-05-01

    How do our abilities to process number and other continuous quantities such as time and space relate to each other? Recent evidence suggests that these abilities share common magnitude processing and neural resources, although other findings also highlight the role of dimension-specific processes. To further characterize the relation between number, time, and space, we first examined them in a population with a developmental numerical dysfunction (developmental dyscalculia) and then assessed the extent to which these abilities correlated both behaviorally and anatomically in numerically normal participants. We found that (1) participants with dyscalculia showed preserved continuous quantity processing and (2) in numerically normal adults, numerical and continuous quantity abilities were at least partially dissociated both behaviorally and anatomically. Specifically, gray matter volume correlated with both measures of numerical and continuous quantity processing in the right TPJ; in contrast, individual differences in number proficiency were associated with gray matter volume in number-specific cortical regions in the right parietal lobe. Together, our new converging evidence of selective numerical impairment and of number-specific brain areas at least partially distinct from common magnitude areas suggests that the human brain is equipped with different ways of quantifying the outside world.

  19. Relation between Resting State Front-Parietal EEG Coherence and Executive Function in Parkinson's Disease

    Science.gov (United States)

    Teramoto, Hiroko; Akimoto, Takayoshi; Shiota, Hiroshi; Kamei, Satoshi

    2016-01-01

    Objective. To assess the relation between executive dysfunction (ED) in Parkinson's disease (PD) and resting state functional connectivity evaluated using electroencephalography (EEG) coherence. Methods. Sixty-eight nondemented sporadic PD patients were assessed using the Behavioural Assessment of the Dysexecutive Syndrome (BADS) to evaluate executive function. EEG coherence in the left frontoparietal electrode pair (F3-P3) and the right frontoparietal electrode pair (F4-P4) was analyzed in the alpha and theta range. The BADS scores were compared across the coherence groups, and the multiple logistic regression analysis was performed to assess the contribution of confounders. Results. The standardized BADS score was significantly lower in the low F3-P3 coherence group in the alpha range (Mann-Whitney U test, p = 0.032), though there was no difference between F4-P4 coherence group in the alpha range, F3-P3, and F4-P4 coherence groups in the theta range and the standardized BADS score. The multiple logistic regression analysis revealed the significant relation between the F3-P3 coherence group in alpha range and age-controlled standardized BADS score (p = 0.039, 95% CI = 1.002–1.062). Conclusion. The decrease in resting state functional connectivity between the frontal and parietal cortices especially in the left side is related to ED in PD. PMID:27433473

  20. Insights from Neuropsychology: Pinpointing the role of the Posterior Parietal Cortex in Episodic and Working Memory

    Directory of Open Access Journals (Sweden)

    Marian E. Berryhill

    2012-06-01

    Full Text Available The role of posterior parietal cortex (PPC in various forms of memory is a current topic of interest in the broader field of cognitive neuroscience. This large cortical region has been linked with a wide range of mnemonic functions affecting each stage of memory processing: encoding, maintenance and retrieval. Yet, the precise role of the PPC in memory remains mysterious and controversial. Progress in understanding PPC function will require researchers to incorporate findings in a convergent manner from multiple experimental techniques rather than emphasizing a particular type of data. To facilitate this process, here, we review findings from the human neuropsychological research and examine the consequences to memory following PPC damage. Recent patient-based research findings have investigated two typically disconnected fields: working memory and episodic memory. The findings from patient participants with unilateral and bilateral PPC lesions performing diverse experimental paradigms are summarized. These findings are then related to findings from other techniques including neurostimulation (TMS and tDCS and the influential and more abundant functional neuroimaging literature. We then review the strengths and weaknesses of hypotheses proposed to account for PPC function in these forms of memory. Finally, we address what missing evidence is needed to clarify the role(s of the PPC in memory.

  1. A key region in the human parietal cortex for processing proprioceptive hand feedback during reaching movements.

    Science.gov (United States)

    Reichenbach, Alexandra; Thielscher, Axel; Peer, Angelika; Bülthoff, Heinrich H; Bresciani, Jean-Pierre

    2014-01-01

    Seemingly effortless, we adjust our movements to continuously changing environments. After initiation of a goal-directed movement, the motor command is under constant control of sensory feedback loops. The main sensory signals contributing to movement control are vision and proprioception. Recent neuroimaging studies have focused mainly on identifying the parts of the posterior parietal cortex (PPC) that contribute to visually guided movements. We used event-related TMS and force perturbations of the reaching hand to test whether the same sub-regions of the left PPC contribute to the processing of proprioceptive-only and of multi-sensory information about hand position when reaching for a visual target. TMS over two distinct stimulation sites elicited differential effects: TMS applied over the posterior part of the medial intraparietal sulcus (mIPS) compromised reaching accuracy when proprioception was the only sensory information available for correcting the reaching error. When visual feedback of the hand was available, TMS over the anterior intraparietal sulcus (aIPS) prolonged reaching time. Our results show for the first time the causal involvement of the posterior mIPS in processing proprioceptive feedback for online reaching control, and demonstrate that distinct cortical areas process proprioceptive-only and multi-sensory information for fast feedback corrections.

  2. Interplay Between Grip and Vision in the Monkey Medial Parietal Lobe.

    Science.gov (United States)

    Breveglieri, Rossella; De Vitis, Marina; Bosco, Annalisa; Galletti, Claudio; Fattori, Patrizia

    2017-05-03

    We aimed at understanding the relative contribution of visual information and hand shaping to the neuronal activity of medial posterior parietal area V6A, a newly added area in the monkey cortical grasping circuit. Two Macaca fascicularis performed a Reach-to-Grasp task in the dark and in the light, grasping objects of different shapes. We found that V6A contains Visual cells, activated only during grasping in the light; Motor neurons, equally activated during grasping in the dark and in the light; Visuomotor cells, differently activated while grasping in the dark and in the light. Visual, Motor, and Visuomotor neurons were moderately or highly selective during grasping, whereas they reduced their selectivity during object observation without performing grasping. The use of the same experimental design employed in the dorsolateral grasping area AIP by other authors allowed us to compare the grasp-related properties of V6A and AIP. From these data and from the literature a frame emerges with many similarities between medial grasping area V6A and lateral grasping area AIP: both areas update and control prehension, with V6A less sensitive than AIP to fine visual details of the objects to be grasped, but more involved in coordinating reaching and grasping. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  3. Temporal structure in neuronal activity during working memory in Macaque parietal cortex

    CERN Document Server

    Pesaran, B; Sahami, M; Mitra, P; Andersen, R A

    2000-01-01

    A number of cortical structures are reported to have elevated single unit firing rates sustained throughout the memory period of a working memory task. How the nervous system forms and maintains these memories is unknown but reverberating neuronal network activity is thought to be important. We studied the temporal structure of single unit (SU) activity and simultaneously recorded local field potential (LFP) activity from area LIP in the inferior parietal lobe of two awake macaques during a memory-saccade task. Using multitaper techniques for spectral analysis, which play an important role in obtaining the present results, we find elevations in spectral power in a 50--90 Hz (gamma) frequency band during the memory period in both SU and LFP activity. The activity is tuned to the direction of the saccade providing evidence for temporal structure that codes for movement plans during working memory. We also find SU and LFP activity are coherent during the memory period in the 50--90 Hz gamma band and no consisten...

  4. Morphometric characteristics of neuropeptide Y immunoreactive neurons in cortex of human inferior parietal lobule.

    Science.gov (United States)

    Krivokuća, Dragan; Puskas, Laslo; Puskas, Nela; Erić, Mirela

    2010-03-01

    The aim of this study was to demonstrate and precisely define the morphology of neurons immunoreactive to neuropeptide Y (NPY) in cortex of human inferior parietal lobule (IPL). Five human brains were used for immunohistochemical investigation of the shape and laminar distribution of NPY neurons in serial section in the supramarginal and angular gyrus. Immunoreactivity to NPY was detected in all six layers of the cortex of human IPL. However a great number of NPY immunoreactive neurons were found in the white matter under the IPL cortex. The following types of NPY immunoreactive neurons were found: Cajal-Retzius, pyramidal, inverted pyramidal, "double bouquet" (bitufted), rare type 6, multipolar nonspinous, bipolar, voluminous "basket", and chandelier cells. These informations about morphometric characteristics of NPY immunoreactive neurons in cortical layers, together with morphometric data taken from brains having schizophrenia or Alzheimer's-type dementia may contribute to better understanding patogenesis of these neurological diseases. The finding of Cajal-Retzius neurons immunoreactive to NPY points to the need for further investigations because of great importance of these cells in neurogenesis and involvement in mentioned diseases instead of their rarity.

  5. Theta-burst transcranial magnetic stimulation to the prefrontal or parietal cortex does not impair metacognitive visual awareness

    Science.gov (United States)

    Bor, Daniel; Schwartzman, David J.; Barrett, Adam B.; Seth, Anil K.

    2017-01-01

    Neuroimaging studies commonly associate dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex with conscious perception. However, such studies only investigate correlation, rather than causation. In addition, many studies conflate objective performance with subjective awareness. In an influential recent paper, Rounis and colleagues addressed these issues by showing that continuous theta burst transcranial magnetic stimulation (cTBS) applied to the DLPFC impaired metacognitive (subjective) awareness for a perceptual task, while objective performance was kept constant. We attempted to replicate this finding, with minor modifications, including an active cTBS control site. Using a between-subjects design for both DLPFC and posterior parietal cortices, we found no evidence of a cTBS-induced metacognitive impairment. In a second experiment, we devised a highly rigorous within-subjects cTBS design for DLPFC, but again failed to find any evidence of metacognitive impairment. One crucial difference between our results and the Rounis study is our strict exclusion of data deemed unsuitable for a signal detection theory analysis. Indeed, when we included this unstable data, a significant, though invalid, metacognitive impairment was found. These results cast doubt on previous findings relating metacognitive awareness to DLPFC, and inform the current debate concerning whether or not prefrontal regions are preferentially implicated in conscious perception. PMID:28192502

  6. Neurologic Outcome After Resection of Parietal Lobe Including Primary Somatosensory Cortex: Implications of Additional Resection of Posterior Parietal Cortex.

    Science.gov (United States)

    Kim, Young-Hoon; Kim, June Sic; Lee, Sang Kun; Chung, Chun Kee

    2017-10-01

    Postoperative neurologic outcomes after primary somatosensory cortex (S1) resection have not been well documented. This study was designed to evaluate the neurologic deterioration that follows resection of the S1 areas and to assess the risk factors associated with these morbidities. We reviewed 48 consecutive patients with medically intractable epilepsy who underwent resection of the S1 and/or the adjacent cortex. The 48 patients were categorized into 4 groups according to the resected area as seen on postoperative magnetic resonance images: group 1 (resection of S1 only; n = 4), 2 (the posterior parietal cortex [PPC] only; n = 24), 3 (S1 and PPC; n = 10), and 4 (S1 and precentral gyrus; n = 10). After the resection of S1 areas, 19 patients (40%) experienced neurologic worsening, including 6 (13%) with permanent and 13 (27%) with transient deficits. Patients with permanent deficits included 2 with motor dysphasia, 1 with dysesthesia, 2 with equilibrium impairments, and 1 with fine movement disturbance of the hand. The overall and permanent neurologic risks were 25% and 0% in group 1, 17% and 4% in group 2, 80% and 20% in group 3, and 60% and 30% in group 4, respectively. Multivariate analysis determined that the resection of both S1 and PPC was the only significant risk factor for neurologic deficits (P = 0.002). The neurologic risk of the resection of S1 and/or its adjacent cortical areas was 40%. The additional resection of the PPC was significantly associated with the development of postoperative neurologic impairments. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Statistics of superior records

    Science.gov (United States)

    Ben-Naim, E.; Krapivsky, P. L.

    2013-08-01

    We study statistics of records in a sequence of random variables. These identical and independently distributed variables are drawn from the parent distribution ρ. The running record equals the maximum of all elements in the sequence up to a given point. We define a superior sequence as one where all running records are above the average record expected for the parent distribution ρ. We find that the fraction of superior sequences SN decays algebraically with sequence length N, SN˜N-β in the limit N→∞. Interestingly, the decay exponent β is nontrivial, being the root of an integral equation. For example, when ρ is a uniform distribution with compact support, we find β=0.450265. In general, the tail of the parent distribution governs the exponent β. We also consider the dual problem of inferior sequences, where all records are below average, and find that the fraction of inferior sequences IN decays algebraically, albeit with a different decay exponent, IN˜N-α. We use the above statistical measures to analyze earthquake data.

  8. Frenillo labial superior doble

    Directory of Open Access Journals (Sweden)

    Carlos Albornoz López del Castillo

    Full Text Available El frenillo labial superior doble no sindrómico es una anomalía del desarrollo que no hemos encontrado reportada en la revisión bibliográfica realizada. Se presenta una niña de 11 años de edad que fue remitida al servicio de Cirugía Maxilofacial del Hospital "Eduardo Agramonte Piña", de Camagüey, por presentar un frenillo labial superior doble de baja inserción. Se describen los síntomas clínicos asociados a esta anomalía y el tratamiento quirúrgico utilizado para su solución: una frenectomía y plastia sobre la banda muscular frénica anormal que provocaba exceso de tejido en la mucosa labial. Consideramos muy interesante la descripción de este caso, por no haber encontrado reporte similar en la literatura revisada.

  9. Decrease in the cortical intensity on T{sub 2}-weighted magnetic resonance imaging with aging in normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Imon, Yukari; Murata, Yoshio; Kajima, Toshio; Nakamura, Shigenobu [Hiroshima Univ. (Japan). School of Medicine; Yamaguchi, Shinya

    1997-03-01

    We reported previously that Low T{sub 2} intensity areas (LIAs) are more common in patients with central nervous system (CNS) diseases than in those with no such diseases, and that the occurrence of LIAs increases with aging. To determine a relationship between the intensity changes and aging, we investigated the intensity of the cerebral cortex in 26 normal Japanese individuals. Measurements of brain MRIs were performed with a Signa Advantage apparatus at 1.5 tesla. T{sub 2}-weighted images were obtained using the spin-echo pulse sequences. On our laboratory console, we measured signal intensities in the regions of interest in the prefrontal, motor, sensory, parietal, temporal, or occipital cortex, and in the frontal white matter. To remove the effect of the system gain settings on signal intensity, that of cerebrospinal fluid was used as reference according to the method of Pujol et al. The average intensity in the temporal and prefrontal cortices was the highest, followed in order by the parietal, sensory, motor, and occipital cortices. The intensity in the temporal and parietal cortices decreased significantly with aging, and that in the motor and sensory cortices had a tendency to decrease with aging. The intensity in the motor and sensory cortices of the elderly subjects and that in the occipital cortex throughout all ages were lower than that in the prefrontal white matter, which would result in the appearance of LIAs. The average intensity of each cerebral cortex was inversely related to the non-heme iron content previously reported. It is likely that the difference in intensity among the cortices reflects variations of the non-heme iron content, and that the change in intensity with aging could be due to the increase in such cortical senile changes as that of microglia, astroglia, and senile plaques, which contain iron or iron-related proteins. The temporal cortex is most susceptible to senile changes. (K.H.)

  10. Social Suppressive Behavior Is Organized by the Spatiotemporal Integration of Multiple Cortical Regions in the Japanese Macaque.

    Directory of Open Access Journals (Sweden)

    Naoya Oosugi

    Full Text Available Under social conflict, monkeys develop hierarchical positions through social interactions. Once the hierarchy is established, the dominant monkey dominates the space around itself and the submissive monkey tries not to violate this space. Previous studies have shown the contributions of the frontal and parietal cortices in social suppression, but the contributions of other cortical areas to suppressive functions remain elusive. We recorded neural activity in large cortical areas using electrocorticographic (ECoG arrays while monkeys performed a social food-grab task in which a target monkey was paired with either a dominant or a submissive monkey. If the paired monkey was dominant, the target monkey avoided taking food in the shared conflict space, but not in other areas. By contrast, when the paired monkey was submissive, the target monkey took the food freely without hesitation. We applied decoding analysis to the ECoG data to see when and which cortical areas contribute to social behavioral suppression. Neural information discriminating the social condition was more evident when the conflict space was set in the area contralateral to the recording hemisphere. We found that the information increased as the social pressure increased during the task. Before food presentation, when the pressure was relatively low, the parietal and somatosensory-motor cortices showed sustained discrimination of the social condition. After food presentation, when the monkey faced greater pressure to make a decision as to whether it should take the food, the prefrontal and visual cortices started to develop buildup responses. The social representation was found in a sustained form in the parietal and somatosensory-motor regions, followed by additional buildup form in the visual and prefrontal cortices. The representation was less influenced by reward expectation. These findings suggest that social adaptation is achieved by a higher-order self-regulation process

  11. Cortical Amyloid β Deposition and Current Depressive Symptoms in Alzheimer Disease and Mild Cognitive Impairment.

    Science.gov (United States)

    Chung, Jun Ku; Plitman, Eric; Nakajima, Shinichiro; Chakravarty, M Mallar; Caravaggio, Fernando; Gerretsen, Philip; Iwata, Yusuke; Graff-Guerrero, Ariel

    2016-05-01

    Depressive symptoms are frequently seen in patients with dementia and mild cognitive impairment (MCI). Evidence suggests that there may be a link between current depressive symptoms and Alzheimer disease (AD)-associated pathological changes, such as an increase in cortical amyloid-β (Aβ). However, limited in vivo studies have explored the relationship between current depressive symptoms and cortical Aβ in patients with MCI and AD. Our study, using a large sample of 455 patients with MCI and 153 patients with AD from the Alzheimer's disease Neuroimaging Initiatives, investigated whether current depressive symptoms are related to cortical Aβ deposition. Depressive symptoms were assessed using the Geriatric Depression Scale and Neuropsychiatric Inventory-depression/dysphoria. Cortical Aβ was quantified using positron emission tomography with the Aβ probe(18)F-florbetapir (AV-45).(18)F-florbetapir standardized uptake value ratio (AV-45 SUVR) from the frontal, cingulate, parietal, and temporal regions was estimated. A global AV-45 SUVR, defined as the average of frontal, cingulate, precuneus, and parietal cortex, was also used. We observed that current depressive symptoms were not related to cortical Aβ, after controlling for potential confounds, including history of major depression. We also observed that there was no difference in cortical Aβ between matched participants with high and low depressive symptoms, as well as no difference between matched participants with the presence and absence of depressive symptoms. The association between depression and cortical Aβ deposition does not exist, but the relationship is highly influenced by stressful events in the past, such as previous depressive episodes, and complex interactions of different pathways underlying both depression and dementia.

  12. Cortical Morphology Characteristics of Young Offspring of Patients With Schizophrenia or Bipolar Disorder.

    Science.gov (United States)

    Sugranyes, Gisela; Solé-Padullés, Cristina; de la Serna, Elena; Borras, Roger; Romero, Soledad; Sanchez-Gistau, Vanessa; Garcia-Rizo, Clemente; Goikolea, Jose Manuel; Bargallo, Nuria; Moreno, Dolores; Baeza, Inmaculada; Castro-Fornieles, Josefina

    2017-01-01

    Cortical surface area and thickness abnormalities have been observed in patients with schizophrenia and bipolar disorders; however, no study thus far has examined cortical morphologic measurements in children and adolescents at genetic risk for the disorders comparatively. One hundred thirty-seven participants, including 36 offspring of patients with schizophrenia (SzO), 54 offspring of patients with bipolar disorder (BpO), and 47 offspring of community controls (CcO), 6 to 17 years old, were assessed with clinical and neuroimaging methods. Sixty-nine percent of the sample was reassessed at a 27.6-month (mean) follow-up. Cortical surface reconstruction was applied to measure cortical area and thickness using FreeSurfer; mixed-effects models were used to investigate cross-sectional and longitudinal differences in global and lobar morphologic measurements. The SzO group exhibited a cross-sectional decrease in global, parietal, and occipital lobe surface area compared with the CcO group, and in the occipital lobe compared with the BpO group. In the SzO group, global and parietal surface area values were inversely associated with attenuated positive and negative prodromal symptom scores. No cross-sectional differences in cortical thickness were observed. Division of the sample by pubertal status showed group-by-time interactions in the pubertal and postpubertal SzO subgroup, with less longitudinal decrease in cortical surface area and thickness than in the CcO and BpO subgroups, respectively. The SzO, but not the BpO, group was characterized by cross-sectional decreases in surface area, and this was associated with prodromal symptoms. Longitudinal changes in cortical morphology associated with risk for schizophrenia may be expressed differently according to developmental stage. Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

  13. Predictors of coupling between structural and functional cortical networks in normal aging.

    Science.gov (United States)

    Romero-Garcia, Rafael; Atienza, Mercedes; Cantero, Jose L

    2014-06-01

    Understanding how the mammalian neocortex creates cognition largely depends on knowledge about large-scale cortical organization. Accumulated evidence has illuminated cortical substrates of cognition across the lifespan, but how topological properties of cortical networks support structure-function relationships in normal aging remains an open question. Here we investigate the role of connections (i.e., short/long and direct/indirect) and node properties (i.e., centrality and modularity) in predicting functional-structural connectivity coupling in healthy elderly subjects. Connectivity networks were derived from correlations of cortical thickness and cortical glucose consumption in resting state. Local-direct connections (i.e., nodes separated by less than 30 mm) and node modularity (i.e., a set of nodes highly interconnected within a topological community and sparsely interconnected with nodes from other modules) in the functional network were identified as the main determinants of coupling between cortical networks, suggesting that the structural network in aging is mainly constrained by functional topological properties involved in the segregation of information, likely due to aging-related deficits in functional integration. This hypothesis is supported by an enhanced connectivity between cortical regions of different resting-state networks involved in sensorimotor and memory functions in detrimental to associations between fronto-parietal regions supporting executive processes. Taken collectively, these findings open new avenues to identify aging-related failures in the anatomo-functional organization of the neocortical mantle, and might contribute to early detection of prevalent neurodegenerative conditions occurring in the late life.

  14. 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

  15. 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.

  16. Cortical Button Fixation: A Better Patellar Tendon Repair?

    Science.gov (United States)

    Ode, Gabriella E; Piasecki, Dana P; Habet, Nahir A; Peindl, Richard D

    2016-10-01

    Patellar tendon ruptures require surgical repair to optimize outcomes, but no consensus exists regarding the ideal repair technique. Cortical button fixation is a secure method for tendon repair that has not been studied in patellar tendons. Cortical button repair is biomechanically superior to the standard transpatellar repair and biomechanically equivalent to suture anchor repair. Controlled laboratory study. Twenty-three fresh-frozen cadaveric knees were used to compare 3 techniques of patellar tendon repair after a simulated rupture at the inferior pole of the patella. Repairs were performed at 45° of flexion using a standard transpatellar suture repair (n = 7), polyetheretherketone (PEEK) suture anchor repair (n = 8), or cortical button repair (n = 8). All specimens were tested on a custom apparatus to simulate cyclic open kinetic chain quadriceps contraction from extension to 90(o) of flexion. Outcomes of gap formation up to 250 cycles, maximum load to failure, and mode of failure were evaluated. Cortical button repair had significantly less gap formation than anchor repair after 1 cycle (P button repair sustained significantly higher loads to failure than anchor repair and suture repair (P button repairs either failed through the suture (n = 5), secondary failure of the patellar tendon (n = 2), or subsidence of the button through the anterior cortex of the patella (n = 1). Patellar tendon repair using cortical button fixation demonstrated mechanical advantages over suture repair and anchor repair in cadaveric specimens. Cortical button fixation showed less cyclic gap formation and withstood at least twice the load to failure of the construct. The biomechanical superiority of cortical button fixation may impart clinical advantages in accelerating postoperative rehabilitation. © 2016 The Author(s).

  17. Differential representation of arm movement direction in relation to cortical anatomy and function

    Science.gov (United States)

    Ball, Tonio; Schulze-Bonhage, Andreas; Aertsen, Ad; Mehring, Carsten

    2009-02-01

    Information about arm movement direction in neuronal activity of the cerebral cortex can be used for movement control mediated by a brain-machine interface (BMI). Here we provide a topographic analysis of the information related to arm movement direction that can be extracted from single trials of electrocorticographic (ECoG) signals recorded from the human frontal and parietal cortex based on a precise assignment of ECoG recording channels to the subjects' individual cortical anatomy and function. To this aim, each electrode contact was identified on structural MRI scans acquired while the electrodes were implanted and was thus related to the brain anatomy of each patient. Cortical function was assessed by direct cortical electrical stimulation. We show that activity from the primary motor cortex, in particular from the region showing hand and arm motor responses upon electrical stimulation, carries most directional information. The premotor, posterior parietal and lateral prefrontal cortex contributed gradually less, but still significant information. This gradient was observed for decoding from movement-related potentials, and from spectral amplitude modulations in low frequencies and in the high gamma band. Our findings thus demonstrate a close topographic correlation between cortical functional anatomy and direction-related information in humans that might be used for brain-machine interfacing.

  18. How the human brain goes virtual: distinct cortical regions of the person-processing network are involved in self-identification with virtual agents.

    Science.gov (United States)

    Ganesh, Shanti; van Schie, Hein T; de Lange, Floris P; Thompson, Evan; Wigboldus, Daniël H J

    2012-07-01

    Millions of people worldwide engage in online role-playing with their avatar, a virtual agent that represents the self. Previous behavioral studies have indicated that many gamers identify more strongly with their avatar than with their biological self. Through their avatar, gamers develop social networks and learn new social-cognitive skills. The cognitive neurosciences have yet to identify the neural processes that underlie self-identification with these virtual agents. We applied functional neuroimaging to 22 long-term online gamers and 21 nongaming controls, while they rated personality traits of self, avatar, and familiar others. Strikingly, neuroimaging data revealed greater avatar-referential cortical activity in the left inferior parietal lobe, a region associated with self-identification from a third-person perspective. The magnitude of this brain activity correlated positively with the propensity to incorporate external body enhancements into one's bodily identity. Avatar-referencing furthermore recruited greater activity in the rostral anterior cingulate gyrus, suggesting relatively greater emotional self-involvement with one's avatar. Post-scanning behavioral data revealed superior recognition memory for avatar relative to others. Interestingly, memory for avatar positively covaried with play duration. These findings significantly advance our knowledge about the brain's plasticity to self-identify with virtual agents and the human cognitive-affective potential to live and learn in virtual worlds.

  19. Syndecan-1 in the mouse parietal peritoneum microcirculation in inflammation.

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    Paulina M Kowalewska

    Full Text Available BACKGROUND: The heparan sulfate proteoglycan syndecan-1 (CD138 was shown to regulate inflammatory responses by binding chemokines and cytokines and interacting with adhesion molecules, thereby modulating leukocyte trafficking to tissues. The objectives of this study were to examine the expression of syndecan-1 and its role in leukocyte recruitment and chemokine presentation in the microcirculation underlying the parietal peritoneum. METHODS: Wild-type BALB/c and syndecan-1 null mice were stimulated with an intraperitoneal injection of Staphylococcus aureus LTA, Escherichia coli LPS or TNFα and the microcirculation of the parietal peritoneum was examined by intravital microscopy after 4 hours. Fluorescence confocal microscopy was used to examine syndecan-1 expression in the peritoneal microcirculation using fluorescent antibodies. Blocking antibodies to adhesion molecules were used to examine the role of these molecules in leukocyte-endothelial cell interactions in response to LTA. To determine whether syndecan-1 co-localizes with chemokines in vivo, fluorescent antibodies to syndecan-1 were co-injected intravenously with anti-MIP-2 (CXCL2, anti-KC (CXCL1 or anti-MCP-1 (CCL2. RESULTS AND CONCLUSION: Syndecan-1 was localized to the subendothelial region of peritoneal venules and the mesothelial layer. Leukocyte rolling was significantly decreased with LPS treatment while LTA and TNFα significantly increased leukocyte adhesion compared with saline control. Leukocyte-endothelial cell interactions were not different in syndecan-1 null mice. Antibody blockade of β2 integrin (CD18, ICAM-1 (CD54 and VCAM-1 (CD106 did not decrease leukocyte adhesion in response to LTA challenge while blockade of P-selectin (CD62P abrogated leukocyte rolling. Lastly, MIP-2 expression in the peritoneal venules was not dependent on syndecan-1 in vivo. Our data suggest that syndecan-1 is expressed in the parietal peritoneum microvasculature but does not regulate leukocyte

  20. Activity in right temporo-parietal junction is not selective for theory-of-mind.

    Science.gov (United States)

    Mitchell, Jason P

    2008-02-01

    Recent researchers have suggested that a region of right temporo-parietal junction (RTPJ) selectively subserves the attribution of beliefs to other people (Saxe R, Kanwisher N. 2003. People thinking about thinking people: fMRI investigations of theory of mind. NeuroImage. 19:1835-1842; Saxe R, Powell LJ. 2006. It's the thought that counts: specific brain regions for one component of theory of mind. Psychol Sci. 17:692-699; Saxe R, Wexler A. 2005. Making sense of another mind: the role of the right temporo-parietal junction. Neuropsychologia. 43:1391-1399). At the same time, a similar RTPJ region has been observed repeatedly in a variety of nonsocial tasks that require participants to redirect attention to task-relevant stimuli (e.g., Corbetta M, Shulman GL. 2002. Control of goal-directed and stimulus-driven attention in the brain. Nat Rev Neurosci. 3:201-215; Serences JT, Shomstein S, Leber AB, Golay X, Egeth HE, Yantis S. 2005. Coordination of voluntary and stimulus-driven attentional control in human cortex. Psychol Sci. 16:114-122). However, because these 2 sets of tasks have never been compared within the same participants, it remains unclear whether these observations refer to the exact same region of RTPJ or may instead involve neighboring regions with distinct functional profiles. To test the claim that there is a region of RTPJ selective for belief attribution, the current study used functional neuroimaging to examine the extent to which cortical loci identified by a "theory-of-mind localizer" also distinguish between trials on a target detection task that varied demands to reorient attention (i.e., a version of the "Posner cueing task"). Results were incompatible with claims of RTPJ selectivity for mental state attribution. Regardless of whether regions were defined from group analyses or were individually tailored for each participant, RTPJ activity was also modulated by the nonsocial attentional task. The overlap between theory-of-mind and attentional

  1. Amyloid burden and metabolic function in early-onset Alzheimer's disease: parietal lobe involvement.

    Science.gov (United States)

    Ossenkoppele, Rik; Zwan, Marissa D; Tolboom, Nelleke; van Assema, Danielle M E; Adriaanse, Sofie F; Kloet, Reina W; Boellaard, Ronald; Windhorst, Albert D; Barkhof, Frederik; Lammertsma, Adriaan A; Scheltens, Philip; van der Flier, Wiesje M; van Berckel, Bart N M

    2012-07-01

    Alzheimer's disease with early onset often presents with a distinct cognitive profile, potentially reflecting a different distribution of underlying neuropathology. The purpose of this study was to examine the relationships between age and both in vivo fibrillary amyloid deposition and glucose metabolism in patients with Alzheimer's disease. Dynamic [(11)C]Pittsburgh compound-B (90 min) and static [(18)F]fluorodeoxyglucose (15 min) scans were obtained in 100 patients with Alzheimer's disease and 20 healthy controls. Parametric non-displaceable binding potential images of [(11)C]Pittsburgh compound-B and standardized uptake value ratio images of [(18)F]fluorodeoxyglucose were generated using cerebellar grey matter as reference tissue. Nine [(11)C]Pittsburgh compound-B-negative patients were excluded. The remaining patients were categorized into younger (n=45, age: 56 ± 4 years) and older (n=46, age: 69 ± 5 years) groups, based on the median age (62 years) at time of diagnosis. Younger patients showed more severe impairment on visuo-spatial function, attention and executive function composite scores (Pparietal and occipital and posterior cingulate cortices) as within subjects factor and [(11)C]Pittsburgh compound-B binding/[(18)F]fluorodeoxyglucose uptake as dependent variables. There was no main effect of age for [(11)C]Pittsburgh compound-B or [(18)F]fluorodeoxyglucose, suggesting that overall, the extent of amyloid deposition or glucose hypometabolism did not differ between groups. Regional distributions of [(11)C]Pittsburgh compound-B binding and [(18)F]fluorodeoxyglucose uptake (both P for interaction parietal cortex of younger patients (both Pparietal [(11)C]Pittsburgh compound-B binding for younger patients (standardized β: -0.37) and between visuo-spatial functioning and occipital binding for older patients (standardized β: -0.39). For [(18)F]fluorodeoxyglucose, associations were found between parietal uptake with visuo-spatial (standardized β: 0

  2. 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.

  3. Hereditary cranium bifidum persisting as enlarged parietal foramina (Catlin marks) on cephalometric radiographs.

    Science.gov (United States)

    Mupparapu, Muralidhar; Binder, Robert E; Duarte, Fernando

    2006-06-01

    Cranium bifidum occultum is a rare skull ossification disorder referred to as the Catlin mark characterized by ossification defects in the parietal bones. Evidence suggests that this condition has a strong genetic heterogenicity. It is believed that, as calvarial growth continues, ossification in parietal bones fills these defects, and they can remain as parietal foramina on either side of the sagittal suture. During the conversion phase of cranium bifidum to the persistent parietal foramen, there will be periods when the brain is unprotected because of the delay in the ossification of the parietal bones. This report describes cranium bifidum occultum diagnosed as an incidental finding in a 14-year-old boy who initially had large bilateral unossified parietal bones and many congenital abnormalities. The patient underwent various surgical procedures over 6 years for the correction of cleft lip and palate. With craniofacial corrections and orthodontic treatment, the patient now has stable dentition and a firm palate with most of the parietal bones ossified. Cranioplasty was not recommended by his family physician after consultation with a neurosurgeon. Orthodontists should be familiar with this genetic abnormality because it causes delay in parietal bone ossification, and they should be able to distinguish between anatomic parietal foramina and enlarged parietal foramina (persistent unossified areas of cranium bifidum occultum), especially when craniofacial abnormalities are noticed.

  4. Sobredentadura total superior implantosoportada

    Directory of Open Access Journals (Sweden)

    Luis Orlando Rodríguez García

    2010-06-01

    Full Text Available Se presenta un caso de un paciente desdentado total superior, rehabilitado en la consulta de implantología de la Clínica "Pedro Ortiz" del municipio Habana del Este en Ciudad de La Habana, Cuba, en el año 2009, mediante prótesis sobre implantes osteointegrados, técnica que se ha incorporado a la práctica estomatológica en Cuba como alternativa al tratamiento convencional en los pacientes desdentados totales. Se siguió un protocolo que comprendió una fase quirúrgica, procedimiento con o sin realización de colgajo y carga precoz o inmediata. Se presenta un paciente masculino de 56 años de edad, que acudió a la consulta multidisciplinaria, preocupado, porque se le habían elaborado tres prótesis en los últimos dos años y ninguna reunía los requisitos de retención que él necesitaba para sentirse seguro y cómodo con las mismas. El resultado final fue la satisfacción total del paciente, con el mejoramiento de la calidad estética y funcional.

  5. [Case of transient cortical blindness due to thrombosis of the transverse sinus].

    Science.gov (United States)

    Mitaki, Shingo; Fukuda, Hitoshi; Kitani, Mitsuhiro

    2008-05-01

    An 62-year-old man presented visual impairment and generalized seizure. Brain CT performed on the day of admission showed thrombus in the right transverse sinus, and DWI showed high intensity areas in the bilateral occipital and parietal lobes. According to bilateral occipital lobe lesions, we considered his visual impairment as cortical blindness. He was diagnosed as venous sinus thrombosis and intravenous heparin, edaravone and osmotic diuretics were administered. MR venography performed after starting of intravenous treatment showed flow gap in the left transverse sinus but no abnormalities in the right transverse sinus. On the second day of hospitalization, his cortical blindness showed improvement and thrombus in the right transverse sinus were disappeared. This indicated that his left transverse sinus originally hypoplastic, thrombus and hemostatis in the right transverse sinus (his dominant side) caused his cortical blindness and generalized seizure. There was a recanalization in the right transverse sinus after heparin therapy.

  6. Coherent delta-band oscillations between cortical areas correlate with decision making

    Science.gov (United States)

    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-01-01

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1–4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making. PMID:23980180

  7. Coherent delta-band oscillations between cortical areas correlate with decision making.

    Science.gov (United States)

    Nácher, Verónica; Ledberg, Anders; Deco, Gustavo; Romo, Ranulfo

    2013-09-10

    Coherent oscillations in the theta-to-gamma frequency range have been proposed as a mechanism that coordinates neural activity in large-scale cortical networks in sensory, motor, and cognitive tasks. Whether this mechanism also involves coherent oscillations at delta frequencies (1-4 Hz) is not known. Rather, delta oscillations have been associated with slow-wave sleep. Here, we show coherent oscillations in the delta frequency band between parietal and frontal cortices during the decision-making component of a somatosensory discrimination task. Importantly, the magnitude of this delta-band coherence is modulated by the different decision alternatives. Furthermore, during control conditions not requiring decision making, delta-band coherences are typically much reduced. Our work indicates an important role for synchronous activity in the delta frequency band when large-scale, distant cortical networks coordinate their neural activity during decision making.

  8. Cortical projection topography of the human splenium: hemispheric asymmetry and individual differences.

    Science.gov (United States)

    Putnam, Mary Colvin; Steven, Megan S; Doron, Karl W; Riggall, Adam C; Gazzaniga, Michael S

    2010-08-01

    The corpus callosum is the largest white matter pathway in the human brain. The most posterior portion, known as the splenium, is critical for interhemispheric communication between visual areas. The current study employed diffusion tensor imaging to delineate the complete cortical projection topography of the human splenium. Homotopic and heterotopic connections were revealed between the splenium and the posterior visual areas, including the occipital and the posterior parietal cortices. In nearly one third of participants, there were homotopic connections between the primary visual cortices, suggesting interindividual differences in splenial connectivity. There were also more instances of connections with the right hemisphere, indicating a hemispheric asymmetry in interhemispheric connectivity within the splenium. Combined, these findings demonstrate unique aspects of human interhemispheric connectivity and provide anatomical bases for hemispheric asymmetries in visual processing and a long-described hemispheric asymmetry in speed of interhemispheric communication for visual information.

  9. Asymmetries in numerical density of pyramidal neurons in the fifth layer of the human posterior parietal cortex

    Directory of Open Access Journals (Sweden)

    Đukić-Macut Nataša

    2012-01-01

    Full Text Available Background/Aim. Both superior parietal lobule (SPL of dorsolateral hemispheric surface and precuneus (PEC of medial surface are the parts of posterior parietal cortex. The aim of this study was to determine the numerical density (NV of pyramidal neurons in the layer V of SPL and PEC and their potential differences. Methods. From 20 (40 hemispheres formaline fixed human brains (both sexes; 27- 65 years tissue blocks from SPL and PEC from the left and right hemisphere were used. According to their size the brains were divided into two groups, the group I with the larger left (15 brains and the group II with the larger right hemisphere (5 brains. Serial Nissl sections (5 μm of the left and right SPL and PEC were used for stereological estimation of NV of the layer V pyramidal neurons. Results. NV of pyramidal neurons in the layer V in the left SPL of brains with larger left hemispheres was significantly higher than in the left SPL of brains with larger right hemisphere. Comparing sides in brains with larger left hemisphere, the left SPL had higher NV than the right one, and then the left PEC, and the right SPL had significantly higher NV than the right PEC. Comparing sides in brains with the larger right hemisphere, the left SPL had significantly higher NV than left PEC, but the right SPL had significantly higher NV than left SPL and the right PEC. Conclusion. Generally, there is an inverse relationship of NV between the medial and lateral areas of the human posterior parietal cortex. The obtained values were different between the brains with larger left and right hemispheres, as well as between the SPL and PEC. In all the comparisons the left SPL had the highest values of NV of pyramidal neurons in the layer V (4771.80 mm-3, except in brains with the larger right hemisphere.

  10. 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.

  11. Cortical and subcortical changes in typically developing preadolescent children.

    Science.gov (United States)

    Muftuler, L Tugan; Davis, Elysia Poggi; Buss, Claudia; Head, Kevin; Hasso, Anton N; Sandman, Curt A

    2011-07-05

    There is evidence that abnormal cerebral development during childhood is a risk factor for various cognitive and psychiatric disorders. There is not, however, sufficient normative data available on large samples of typically developing children, especially within the narrow preadolescent age range. We analyzed high resolution MRI images from 126 normally developing children between ages 6 and 10 years. Age related differences in cortical thickness and in the volumes of major subcortical structures were assessed. Thinner cortices were observed in the occipital, parietal and somatosensory regions as well as in distinct regions of the temporal and frontal lobes with increasing age. Among the major subcortical structures analyzed in this study, only the thalamus showed increased volume with age after accounting for intracranial volume. Within the age range studied age-related cortical and subcortical differences were similar for boys and girls except for the right insula, where girls showed a slight increase in thickness with age. The findings reveal age-associated changes in brain anatomy, providing information about the trajectory of normal brain development during late childhood. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Abnormalities in cortical gray matter density in borderline personality disorder.

    Science.gov (United States)

    Rossi, R; Lanfredi, M; Pievani, M; Boccardi, M; Rasser, P E; Thompson, P M; Cavedo, E; Cotelli, M; Rosini, S; Beneduce, R; Bignotti, S; Magni, L R; Rillosi, L; Magnaldi, S; Cobelli, M; Rossi, G; Frisoni, G B

    2015-02-01

    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). 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%). 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 (Pmultiple comparisons via permutation testing. 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. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Cortical Thickness in Dementia with Lewy Bodies and Alzheimer's Disease: A Comparison of Prodromal and Dementia Stages.

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    Frederic Blanc

    Full Text Available To assess and compare cortical thickness (CTh of patients with prodromal Dementia with Lewy bodies (pro-DLB, prodromal Alzheimer's disease (pro-AD, DLB dementia (DLB-d, AD dementia (AD-d and normal ageing.Study participants(28 pro-DLB, 27 pro-AD, 31 DLB-d, 54 AD-d and 33 elderly controls underwent 3Tesla T1 3D MRI and detailed clinical and cognitive assessments. We used FreeSurfer analysis package to measure CTh and investigate patterns of cortical thinning across groups.Comparison of CTh between pro-DLB and pro-AD (p<0.05, FDR corrected showed more right anterior insula thinning in pro-DLB, and more bilateral parietal lobe and left parahippocampal gyri thinning in pro-AD. Comparison of prodromal patients to healthy elderly controls showed the involvement of the same regions. In DLB-d (p<0.05, FDR corrected cortical thinning was found predominantly in the right temporo-parietal junction, and insula, cingulate, orbitofrontal and lateral occipital cortices. In AD-d(p<0.05, FDR corrected,the most significant areas affected included the entorhinal cortices, parahippocampal gyri and parietal lobes. The comparison of AD-d and DLB-d demonstrated more CTh in AD-d in the left entorhinal cortex (p<0.05, FDR corrected.Cortical thickness is a sensitive measure for characterising patterns of grey matter atrophy in early stages of DLB distinct from AD. Right anterior insula involvement may be a key region at the prodromal stage of DLB and needs further investigation.

  14. 'How many' and 'how much' dissociate in the parietal lobe.

    Science.gov (United States)

    Lecce, Francesca; Walsh, Vincent; Didino, Daniele; Cappelletti, Marinella

    2015-12-01

    We investigated whether two features that are fundamental for quantity processing, namely numerosity and continuous quantity - or 'how many' versus 'how much' - may dissociate in the parietal lobe. Fourteen mathematically-normal participants performed a well-established numerosity discrimination task after receiving continuous theta burst transcranial magnetic stimulation (TBS) over the left or right intraparietal sulcus (IPS) or the Vertex. We performed a detailed analysis of accuracy (based on the Weber Fraction, wf), which distinguished between trials in which numerosity was anti-correlated or 'incongruent' to other continuous measures of quantity, and trials in which numerosity and other continuous features were 'congruent'. Congruent trials can be processed by integrating numerosity or continuous quantity features like cumulative area since they correlate. Instead incongruent trials can only be processed based on numerosity and requires inhibiting cumulative area or other continuous quantity features like dot size and would lead to incorrect judgment if these features are used as a proxy for numerosity. We found an increase of wf, i.e., weakened numerosity processing in incongruent but not congruent trials following left IPS-TBS, which suggests that numerosity processing was impaired while continuous quantity processing remained unchanged. Moreover, wf increased in congruent but not in incongruent trials following right IPS stimulation. We concluded that left and right parietal are respectively critical for numerosity discrimination, i.e., 'how many' or alternatively for response selection, and for integrating numerosity and continuous quantity features. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Sense of agency is related to gamma band coupling in an inferior parietal-preSMA circuitry

    DEFF Research Database (Denmark)

    Ritterband-Rosenbaum, Anina; Nielsen, Jens Bo; Christensen, Mark Schram

    2014-01-01

    In the present study we tested whether sense of agency (SoA) is reflected by changes in coupling between right medio-frontal/supplementary motor area (SMA) and inferior parietal cortex (IPC). Twelve healthy adult volunteers participated in the study. They performed a variation of a line-drawing t......In the present study we tested whether sense of agency (SoA) is reflected by changes in coupling between right medio-frontal/supplementary motor area (SMA) and inferior parietal cortex (IPC). Twelve healthy adult volunteers participated in the study. They performed a variation of a line...... as to the agent of the movement and they reported SoA in approximately 50% of trials when the movement was computer-generated. We tested whether IPC-preSMA coupling was associated with SoA, using dynamic causal modeling (DCM) for induced responses (Chen et al., 2008; Herz et al., 2012). Nine different DCMs were...... constructed for the early and late phases of the task, respectively. All models included two regions: a superior medial gyrus (preSMA) region and a right supramarginal gyrus (IPC) region. Bayesian models selection (Stephan et al., 2009) favored a model with input to IPC and modulation of the forward...

  16. Mathematically gifted adolescents mobilize enhanced workspace configuration of theta cortical network during deductive reasoning.

    Science.gov (United States)

    Zhang, L; Gan, J Q; Wang, H

    2015-03-19

    Previous studies have established the importance of the fronto-parietal brain network in the information processing of reasoning. At the level of cortical source analysis, this eletroencepalogram (EEG) study investigates the functional reorganization of the theta-band (4-8Hz) neurocognitive network of mathematically gifted adolescents during deductive reasoning. Depending on the dense increase of long-range phase synchronizations in the reasoning process, math-gifted adolescents show more significant adaptive reorganization and enhanced "workspace" configuration in the theta network as compared with average-ability control subjects. The salient areas are mainly located in the anterior cortical vertices of the fronto-parietal network. Further correlation analyses have shown that the enhanced workspace configuration with respect to the global topological metrics of the theta network in math-gifted subjects is correlated with the intensive frontal midline theta (fm theta) response that is related to strong neural effort for cognitive events. These results suggest that by investing more cognitive resources math-gifted adolescents temporally mobilize an enhanced task-related global neuronal workspace, which is manifested as a highly integrated fronto-parietal information processing network during the reasoning process.

  17. Associations between children's socioeconomic status and prefrontal cortical thickness.

    Science.gov (United States)

    Lawson, Gwendolyn M; Duda, Jeffrey T; Avants, Brian B; Wu, Jue; Farah, Martha J

    2013-09-01

    Childhood socioeconomic status (SES) predicts executive function performance and measures of prefrontal cortical function, but little is known about its anatomical correlates. Structural MRI and demographic data from a sample of 283 healthy children from the NIH MRI Study of Normal Brain Development were used to investigate the relationship between SES and prefrontal cortical thickness. Specifically, we assessed the association between two principal measures of childhood SES, family income and parental education, and gray matter thickness in specific subregions of prefrontal cortex and on the asymmetry of these areas. After correcting for multiple comparisons and controlling for potentially confounding variables, parental education significantly predicted cortical thickness in the right anterior cingulate gyrus and left superior frontal gyrus. These results suggest that brain structure in frontal regions may provide a meaningful link between SES and cognitive function among healthy, typically developing children. © 2013 John Wiley & Sons Ltd.

  18. Role of parietal regions in episodic memory retrieval: The dual attentional processes hypothesis

    OpenAIRE

    Cabeza, Roberto

    2008-01-01

    Although parietal cortex is frequently activated during episodic memory retrieval, damage to this region does not markedly impair episodic memory. To account for these and other findings, a new dual attentional processes (DAP) hypothesis is proposed. According to this hypothesis, dorsal parietal cortex (DPC) contributes top-down attentional processes guided by retrieval goals, whereas ventral parietal cortex (VPC) contributes bottom-up attentional processes captured by the retrieval output. C...

  19. Sex Differences in Parietal Lobe Morphology: Relationship to Mental Rotation Performance

    OpenAIRE

    Koscik, Tim; O’Leary, Dan; Moser, David J; Andreasen, Nancy C; Nopoulos, Peg

    2008-01-01

    Structural magnetic resonance imaging (MRI) studies of the human brain have reported evidence for sexual dimorphism. In addition to sex differences in overall cerebral volume, differences in the proportion of gray matter (GM) to white matter (WM) volume have been observed, particularly in the parietal lobe. To our knowledge there have been no studies examining the relationship between the sex differences in parietal lobe structure and function. The parietal lobe is thought to be involved in s...

  20. Cortical Network Dynamics of Perceptual Decision-Making in the Human Brain

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    Markus eSiegel

    2011-02-01

    Full Text Available Goal-directed behavior requires the flexible transformation of sensory evidence about our environment into motor actions. Studies of perceptual decision-making have shown that this transformation is distributed across several widely separated brain regions. Yet, little is known about how decision-making emerges from the dynamic interactions among these regions. Here, we review a series of studies, in which we characterized the cortical network interactions underlying a perceptual decision process in the human brain. We used magnetoencephalography (MEG to measure the large-scale cortical population dynamics underlying each of the sub-processes involved in this decision: the encoding of sensory evidence and action plan, the mapping between the two, and the attentional selection of task-relevant evidence. We found that these sub-processes are mediated by neuronal oscillations within specific frequency ranges. Localized gamma-band oscillations in sensory and motor cortices reflect the encoding of the sensory evidence and motor plan. Large-scale oscillations across widespread cortical networks mediate the integrative processes connecting these local networks: Gamma- and beta-band oscillations across frontal, parietal and sensory cortices serve the selection of relevant sensory evidence and its flexible mapping onto action plans. In sum, our results suggest that perceptual decisions are mediated by oscillatory interactions within overlapping local and large-scale cortical networks.

  1. Age effects on cortical thickness in young Down's syndrome subjects: a cross-sectional gender study

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Andrea; Moraschi, Marta [San Raffaele Foundation Rome, Rehabilitation Facility Ceglie Messapica, Rome (Italy); Cornia, Riccardo; Stella, Giacomo [University of Modena and Reggio Emilia, Department of Education and Human Sciences, Emilia-Romagna (Italy); Bozzao, Alessandro; Gagliardo, Olga [University Sapienza, NESMOS, Department of Neuroradiology, S. Andrea Hospital, Rome (Italy); Chiacchiararelli, Laura [University Sapienza, Department of Medical Physics, S. Andrea Hospital, Rome (Italy); Iani, Cristina [University of Modena and Reggio Emilia, Department of Communication and Economy, Emilia-Romagna (Italy); Albertini, Giorgio [IRCSS San Raffaele Pisana, Department of Paediatrics, Rome (Italy); Pierallini, Alberto [IRCSS San Raffaele Pisana, Department of Radiology, Rome (Italy)

    2015-04-01

    The aim of this study was to determine differences in the characteristic pattern of age-related cortical thinning in men and women with Down's syndrome (DS) by means of MRI and automatic cortical thickness measurements and a cross-sectional design, in a large cohort of young subjects. Eighty-four subjects with DS, 30 females (11-35 years, mean age ± SD = 22.8 ± 5.9) and 54 males (11-35 years, mean age ± SD = 21.5 ± 6.5), were examined using a 1.5-T scanner. MRI-based quantification of cortical thickness was performed using FreeSurfer software package. For all subjects participating in the study, the Pearson product-moment correlation coefficient between age and mean cortical thickness values has been evaluated. A significant negative correlation between cortical thickness and age was found in female DS subjects, predominantly in frontal and parietal lobes, bilaterally. In male DS subjects, a significant negative correlation between cortical thickness and age was found in the right fronto-temporal lobes and cingulate regions. Whole brain mean cortical thickness values were significantly negative correlated with age only in female DS subjects. Females with Down's syndrome showed a strong correlation between cortical thickness and age, already in early age. We suggest that the cognitive impairment due to hormonal deficit in the postmenopausal period could be emphasized by the early structural decline of gray matter in female DS subjects. (orig.)

  2. Differences in Cortical Sources of the Event-Related P3 Potential Between Young and Old Participants Indicate Frontal Compensation.

    Science.gov (United States)

    van Dinteren, R; Huster, R J; Jongsma, M L A; Kessels, R P C; Arns, M

    2017-01-18

    The event-related P3 potential, as elicited in auditory signal detection tasks, originates from neural activity of multiple cortical structures and presumably reflects an overlap of several cognitive processes. The fact that the P3 is affected by aging makes it a potential metric for age-related cognitive change. The P3 in older participants is thought to encompass frontal compensatory activity in addition to task-related processes. The current study investigates this by decomposing the P3 using group independent component analysis (ICA). Independent components (IC) of young and old participants were compared in order to investigate the effects of aging. Exact low-resolution tomography analysis (eLORETA) was used to compare current source densities between young and old participants for the P3-ICs to localize differences in cortical source activity for every IC. One of the P3-related ICs reflected a different constellation of cortical generators in older participants compared to younger participants, suggesting that this P3-IC reflects shifts in neural activations and compensatory processes with aging. This P3-IC was localized to the orbitofrontal/temporal, and the medio-parietal regions. For this IC, older participants showed more frontal activation and less parietal activation as measured on the scalp. The differences in cortical sources were localized in the precentral gyrus and the parahippocampal gyrus. This finding might reflect compensatory activity recruited from these cortical sources during a signal detection task.

  3. Deep sleep and parietal cortex gene expression changes are related to cognitive deficits with age.

    Directory of Open Access Journals (Sweden)

    Heather M Buechel

    Full Text Available BACKGROUND: Age-related cognitive deficits negatively affect quality of life and can presage serious neurodegenerative disorders. Despite sleep disruption's well-recognized negative influence on cognition, and its prevalence with age, surprisingly few studies have tested sleep's relationship to cognitive aging. METHODOLOGY: We measured sleep stages in young adult and aged F344 rats during inactive (enhanced sleep and active (enhanced wake periods. Animals were behaviorally characterized on the Morris water maze and gene expression profiles of their parietal cortices were taken. PRINCIPAL FINDINGS: Water maze performance was impaired, and inactive period deep sleep was decreased with age. However, increased deep sleep during the active period was most strongly correlated to maze performance. Transcriptional profiles were strongly associated with behavior and age, and were validated against prior studies. Bioinformatic analysis revealed increased translation and decreased myelin/neuronal pathways. CONCLUSIONS: The F344 rat appears to serve as a reasonable model for some common sleep architecture and cognitive changes seen with age in humans, including the cognitively disrupting influence of active period deep sleep. Microarray analysis suggests that the processes engaged by this sleep are consistent with its function. Thus, active period deep sleep appears temporally misaligned but mechanistically intact, leading to the following: first, aged brain tissue appears capable of generating the slow waves necessary for deep sleep, albeit at a weaker intensity than in young. Second, this activity, presented during the active period, seems disruptive rather than beneficial to cognition. Third, this active period deep sleep may be a cognitively pathologic attempt to recover age-related loss of inactive period deep sleep. Finally, therapeutic strategies aimed at reducing active period deep sleep (e.g., by promoting active period wakefulness and/or inactive

  4. Transcranial direct current stimulation of the frontal-parietal-temporal area attenuates smoking behavior.

    Science.gov (United States)

    Meng, Zhiqiang; Liu, Chang; Yu, Chengyang; Ma, Yuanye

    2014-07-01

    Many brain regions are involved in smoking addiction (e.g. insula, ventral tegmental area, prefrontal cortex and hippocampus), and the manipulation of the activity of these brain regions can show a modification of smoking behavior. Low current transcranial direct current stimulation (tDCS) is a noninvasive way to manipulate cortical excitability, and thus brain function and associated behaviors. In this study, we examined the effects of inhibiting the frontal-parietal-temporal association area (FPT) on attention bias to smoking-related cues and smoking behavior in tobacco users. This inhibition is induced by cathodal tDCS stimulation. We tested three stimulation conditions: 1) bilateral cathodal over both sides of FPT; 2) cathodal over right FPT; and 3) sham-tDCS. Visual attention bias to smoking-related cues was evaluated using an eye tracking system. The measurement for smoking behavior was the number of daily cigarettes consumed before and after tDCS treatment. We found that, after bilateral cathodal stimulation of the FPT area, while the attention to smoking-related cues showed a decreased trend, the effects were not significantly different from sham stimulation. The daily cigarette consumption was reduced to a significant level. These effects were not seen under single cathodal tDCS or sham-tDCS. Our results show that low current tDCS of FPT area attenuates smoking cue-related attention and smoking behavior. This non-invasive brain stimulation technique, targeted at FPT areas, might be a promising method for treating smoking behavior.

  5. Anodal transcranial direct current stimulation of parietal cortex enhances action naming in Corticobasal Syndrome

    Directory of Open Access Journals (Sweden)

    Rosa eManenti

    2015-04-01

    Full Text Available Background: Corticobasal Syndrome (CBS is a neurodegenerative disorder that overlaps both clinically and neuropathologically with Frontotemporal dementia and is characterized by apraxia, alien limb phenomena, cortical sensory loss, cognitive impairment, behavioural changes and aphasia. It has been recently demonstrated that transcranial direct current stimulation (tDCS improves naming in healthy subjects and in subjects with language deficits.Objective: The aim of the present study was to explore the extent to which anodal transcranial direct current stimulation (anodal tDCS over the parietal cortex (PARC could facilitate naming performance in CBS subjects. Methods: Anodal tDCS was applied to the left and right PARC during object and action naming in seventeen patients with a diagnosis of possible CBS. Participants underwent two sessions of anodal tDCS (left and right and one session of placebo tDCS. Vocal responses were recorded and analyzed for accuracy and vocal Reaction Times (vRTs. Results: A shortening of naming latency for actions was observed only after active anodal stimulation over the left PARC, as compared to placebo and right stimulations. No effects have been reported for accuracy.Conclusions: Our preliminary finding demonstrated that tDCS decreased vocal reaction time during action naming in a sample of patients with CBS. A possible explanation of our results is that anodal tDCS over the left PARC effects the brain network implicated in action observation and representation. Further studies, based on larger patient samples, should be conducted to investigate the usefulness of tDCS as an additional treatment of linguistic deficits in CBS patients.

  6. Superior Sagittal Sinus Thrombosis Complicating Typhoid Fever in a Teenager

    Directory of Open Access Journals (Sweden)

    P. O. Okunola

    2012-01-01

    Full Text Available Cerebral venous sinus (sinovenous thrombosis (CSVT is a rare life-threatening disorder in childhood that is often misdiagnosed. CSVT encompasses cavernous sinus thrombosis, lateral sinus thrombosis, and superior sagittal sinus thrombosis (SSST. We present an adolescent girl who was well until two weeks earlier when she had a throbbing frontal headache and fever with chills; she later had dyspnoea, jaundice, melena stool, multiple seizures, nuchal rigidity, and monoparesis of the right lower limb a day before admission. Urine test for Salmonella typhi Vi antigen was positive, and Widal reaction was significant. Serial cranial computerized tomography scans revealed an expanding hypodense lesion in the parafalcine region consistent with SSST or a parasagittal abscess. Inadvertent left parietal limited craniectomy confirmed SSST. She recovered completely with subsequent conservative management. Beyond neuropsychiatric complications of Typhoid fever, CSVT should be highly considered when focal neurologic deficits are present.

  7. A parietal memory network revealed by multiple MRI methods.

    Science.gov (United States)

    Gilmore, Adrian W; Nelson, Steven M; McDermott, Kathleen B

    2015-09-01

    The manner by which the human brain learns and recognizes stimuli is a matter of ongoing investigation. Through examination of meta-analyses of task-based functional MRI and resting state functional connectivity MRI, we identified a novel network strongly related to learning and memory. Activity within this network at encoding predicts subsequent item memory, and at retrieval differs for recognized and unrecognized items. The direction of activity flips as a function of recent history: from deactivation for novel stimuli to activation for stimuli that are familiar due to recent exposure. We term this network the 'parietal memory network' (PMN) to reflect its broad involvement in human memory processing. We provide a preliminary framework for understanding the key functional properties of the network. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Herpes Simplex Encephalitis of the Parietal Lobe: A Rare Presentation

    Science.gov (United States)

    Tkachenko, Lara; Moisi, Marc; Rostad, Steven; Umeh, Randle; Zwillman, Michael E; Tubbs, R. Shane; Page, Jeni; Newell, David W.; Delashaw, Johnny B

    2016-01-01

    A 69-year-old female with a history of breast cancer and hypertension presented with a rare case of herpes simplex encephalitis (HSE) isolated to her left parietal lobe. The patient’s first biopsy was negative for herpes simplex virus (HSV) I/II antigens, but less than two weeks later, the patient tested positive on repeat biopsy. This initial failure to detect the virus and the similarities between HSE and symptoms of intracranial hemorrhage (ICH) suggests repeat testing for HSV in the presence of ICH. Due to the frequency of patients with extra temporal HSE, a diagnosis of HSE should be more readily considered, particularly when a patient may not be improving and a concrete diagnosis has not been solidified. PMID:27774355

  9. Herpes Simplex Encephalitis of the Parietal Lobe: A Rare Presentation.

    Science.gov (United States)

    Fisahn, Christian; Tkachenko, Lara; Moisi, Marc; Rostad, Steven; Umeh, Randle; Zwillman, Michael E; Tubbs, R Shane; Page, Jeni; Newell, David W; Delashaw, Johnny B

    2016-09-16

    A 69-year-old female with a history of breast cancer and hypertension presented with a rare case of herpes simplex encephalitis (HSE) isolated to her left parietal lobe. The patient's first biopsy was negative for herpes simplex virus (HSV) I/II antigens, but less than two weeks later, the patient tested positive on repeat biopsy. This initial failure to detect the virus and the similarities between HSE and symptoms of intracranial hemorrhage (ICH) suggests repeat testing for HSV in the presence of ICH. Due to the frequency of patients with extra temporal HSE, a diagnosis of HSE should be more readily considered, particularly when a patient may not be improving and a concrete diagnosis has not been solidified.

  10. Scalp Medical Tattooing Technique to Camouflage Bifid Parietal Whorls

    Science.gov (United States)

    You, Seung Hyun

    2016-01-01

    Background: To the best of the authors’ knowledge, no reports have described cosmetic problems arising from the hair direction around the parietal whorl (PW). This study was performed to evaluate the efficacy of scalp medical tattooing technique for camouflaging bifid PWs. Methods: We retrospectively examined the outcomes of scalp medical tattooing in 38 patients who were admitted for camouflage of a bifid PW. Results: All patients’ cosmetic appearance was judged, by both the patients and the surgeon, to be markedly improved. No specific complications occurred, such as infection, hair loss in the operative field, or other problems. Conclusion: Scalp medical tattooing appears to be an effective method that helps to camouflage the see-through appearance of bifid PWs. PMID:27200232

  11. mu-Suppression during Action Observation and Execution Correlates with BOLD in Dorsal Premotor, Inferior Parietal, and SI Cortices

    NARCIS (Netherlands)

    Arnstein, Dan; Cui, Fang; Keysers, Christian; Maurits, Natasha M.; Gazzola, Valeria

    2011-01-01

    The discovery of mirror neurons in the monkey, that fire during both the execution and the observation of the same action, sparked great interest in studying the human equivalent. For over a decade, both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) have been used to

  12. Comparing TMS perturbations to occipital and parietal cortices in concurrent TMS-fMRI studies-Methodological considerations

    DEFF Research Database (Denmark)

    Leitao, Joana; Thielscher, Axel; Tuennerhoff, Johannes

    2017-01-01

    Neglect and hemianopia are two neuropsychological syndromes that are associated with reduced awareness for visual signals in patients' contralesional hemifield. They offer the unique possibility to dissociate the contributions of retino-geniculate and retino-colliculo circuitries in visual...... tutorial guidance on how future studies should compare TMS to primary sensory and association areas that are governed by distinct computational principles, neural dynamics and functional architecture....

  13. Collateral branching of long-distance cortical projections in monkey.

    Science.gov (United States)

    Rockland, Kathleen S

    2013-12-15

    Collateralization of individual cortical axons is well documented for rodents but less so for monkeys, where double retrograde tracer experiments have tended to find only small numbers of neurons projecting to two different injection sites. Evidence from both double label and single axon studies, however, suggests that in specific projection systems the number of neurons with collateralized axons can be 10% or greater. These include feedback projections from temporal areas (but less so those from V4 and MT/V5). Single-axon analyses show that many parietal neurons branch to multiple targets. Except for giant Meynert cells in area V1, feedforward projections from early visual areas have only a small number of neurons with branching axons. Why only some neurons collateralize, what determines branch points and projection foci, and how this impacts network organization are largely unknown. Deciphering the branching code might offer new perspectives on space-time organization at the network level.

  14. Posterior parietal cortex role in a sensorimotor task performance Papel do córtex parietal posterior na realização de uma tarefa sensório-motora

    Directory of Open Access Journals (Sweden)

    Sergio Nader

    2008-06-01

    Full Text Available This study aimed to elucidate electrophysiological and cortical mechanisms involved in anticipatory actions when individuals had to catch balls in free drop; specifically through quantitative electroencephalography (qEEG alpha absolute power changes. The sample was composed for 23 health subjects, both sexes, with ages varying between 25 and 40 years, absence of mental and physical illness, right handed and don't make use of any psychoactive or psychotropic substance at the time of the study. The experiment consisted of a task of catching balls in free drop. The three-way ANOVA analysis demonstrated an interaction between moment and position factors in left parietal posterior cortex (PPC (p=0.001. Through the experimental task employed, this area demonstrated a differentiated activity involving expectation, planning and preparedness in the ball's drop task.O estudo tentou elucidar mecanismos eletrofisiológicos e corticais envolvidos em ações antecipatórias quando os sujeitos testados tiveram que apreender bolas em queda livre; especificamente através de mudanças na potência absoluta na banda alfa da eletrencefalografia quantitativa (EEGq. A amostra foi composta por 23 sujeitos sadios, ambos os sexos, idade entre variando entre 25 e 40 anos, sem comprometimento físico e mental, destros, e não fazer uso de nenhuma substância psicoativa ou psicotrópicos até o momento do estudo. O experimento consistiu de uma tarefa de apreensão de bolas em queda livre. A análise three-way ANOVA demonstrou uma interação entre os fatores momento e posição no córtex parietal posterior (CPP esquerdo (p=0,001. Através da tarefa experimental empregada, esta área demonstrou uma atividade diferenciada envolvendo expectativa, planejamento e prontidão na tarefa de queda de bolas.

  15. Neurofeedback of slow cortical potentials: neural mechanisms and feasibility of a placebo-controlled design in healthy adults

    Directory of Open Access Journals (Sweden)

    Holger eGevensleben

    2014-12-01

    Full Text Available To elucidate basic mechanisms underlying neurofeedback we investigated neural mechanisms of training of slow cortical potentials by considering EEG- and fMRI. Additionally, we analyzed the feasibility of a double-blind, placebo-controlled design in NF research based on regulation performance during treatment sessions and self-assessment of the participants. Twenty healthy adults participated in 16 sessions of SCP training: 9 participants received regular SCP training, 11 participants received sham feedback. At three time points (pre, intermediate, post fMRI and EEG/ERP-measurements were conducted during a continuous performance test (CPT. Performance-data during the sessions (regulation performance in the treatment group and the placebo group were analyzed. Analysis of EEG-activity revealed in the SCP group a strong enhancement of the CNV (electrode Cz at the intermediate assessment, followed by a decrease back to baseline at the post-treatment assessment. In contrast, in the placebo group a continuous but smaller increase of the CNV could be obtained from pre to post assessment. The increase of the CNV in the SCP group at intermediate testing was superior to the enhancement in the placebo group. The changes of the CNV were accompanied by a continuous improvement in the test performance of the CPT from pre to intermediate to post assessment comparable in both groups. The change of the CNV in the SCP group is interpreted as an indicator of neural plasticity and efficiency while an increase of the CNV in the placebo group might reflect learning and improved timing due to the frequent task repetition.In the fMRI analysis evidence was obtained for neuronal plasticity. After regular SCP neurofeedback activation in the posterior parietal cortex decreased from the pre- to the intermediate measurement and increased again in the post measurement, inversely following the U-shaped increase and decrease of the tCNV EEG amplitude in the SCP-trained group

  16. Downregulation of GABA[Subscript A] Receptor Protein Subunits a6, ß2, d, e, ?2, ?, and ?2 in Superior Frontal Cortex of Subjects with Autism

    Science.gov (United States)

    Fatemi, S. Hossein; Reutiman, Teri J.; Folsom, Timothy D.; Rustan, Oyvind G.; Rooney, Robert J.; Thuras, Paul D.

    2014-01-01

    We measured protein and mRNA levels for nine gamma-aminobutyric acid A (GABA[subscript A]) receptor subunits in three brain regions (cerebellum, superior frontal cortex, and parietal cortex) in subjects with autism versus matched controls. We observed changes in mRNA for a number of GABA[subscript A] and GABA[subscript B] subunits and overall…

  17. Cortical Alpha Oscillations Predict Speech Intelligibility

    Science.gov (United States)

    Dimitrijevic, Andrew; Smith, Michael L.; Kadis, Darren S.; Moore, David R.

    2017-01-01

    Understanding speech in noise (SiN) is a complex task involving sensory encoding and cognitive resources including working memory and attention. Previous work has shown that brain oscillations, particularly alpha rhythms (8–12 Hz) play important roles in sensory processes involving working memory and attention. However, no previous study has examined brain oscillations during performance of a continuous speech perception test. The aim of this study was to measure cortical alpha during attentive listening in a commonly used SiN task (digits-in-noise, DiN) to better understand the neural processes associated with “top-down” cognitive processing in adverse listening environments. We recruited 14 normal hearing (NH) young adults. DiN speech reception threshold (SRT) was measured in an initial behavioral experiment. EEG activity was then collected: (i) while performing the DiN near SRT; and (ii) while attending to a silent, close-caption video during presentation of identical digit stimuli that the participant was instructed to ignore. Three main results were obtained: (1) during attentive (“active”) listening to the DiN, a number of distinct neural oscillations were observed (mainly alpha with some beta; 15–30 Hz). No oscillations were observed during attention to the video (“passive” listening); (2) overall, alpha event-related synchronization (ERS) of central/parietal sources were observed during active listening when data were grand averaged across all participants. In some participants, a smaller magnitude alpha event-related desynchronization (ERD), originating in temporal regions, was observed; and (3) when individual EEG trials were sorted according to correct and incorrect digit identification, the temporal alpha ERD was consistently greater on correctly identified trials. No such consistency was observed with the central/parietal alpha ERS. These data demonstrate that changes in alpha activity are specific to listening conditions. To our

  18. Attentional Modulation of Primary Interoceptive and Exteroceptive Cortices

    Science.gov (United States)

    Segal, Zindel V.; Anderson, Adam K.

    2013-01-01

    How exteroceptive attention (EA) alters neural representations of the external world is well characterized, yet little is known about how interoceptive attention (IA) alters neural representations of the body's internal state. We contrasted visual EA against IA toward respiration. Visual EA modulated striate and extrastriate cortices and a lateral frontoparietal “executive” network. By contrast, respiratory IA modulated a posterior insula region sensitive to respiratory frequency, consistent with primary interoceptive cortex, and a posterior limbic and medial parietal network, including the hippocampus, precuneus, and midcingulate cortex. Further distinguishing between EA and IA networks, attention-dependent connectivity analyses revealed that EA enhanced visual cortex connectivity with the inferior parietal lobule and pulvinar of the thalamus, while IA enhanced insula connectivity with the posterior ventromedial thalamus, a relay of the laminar I spinothalamocortical pathway supporting interoceptive afference. Despite strong connectivity between the posterior and the anterior insula, anatomical parcellation of the insula revealed a gradient of IA to EA recruitment along its posterior–anterior axis. These results suggest that distinct networks may support EA and IA. Furthermore, the anterior insula is not an area of pure body awareness but may link representations of the outside world with the body's internal state—a potential basis for emotional experience. PMID:22267308

  19. Cortical recovery of swallowing function in wound botulism

    Directory of Open Access Journals (Sweden)

    Ringelstein Erich B

    2008-05-01

    Full Text Available Abstract Background Botulism is a rare disease caused by intoxication leading to muscle weakness and rapidly progressive dysphagia. With adequate therapy signs of recovery can be observed within several days. In the last few years, brain imaging studies carried out in healthy subjects showed activation of the sensorimotor cortex and the insula during volitional swallowing. However, little is known about cortical changes and compensation mechanisms accompanying swallowing pathology. Methods In this study, we applied whole-head magnetoencephalography (MEG in order to study changes in cortical activation in a 27-year-old patient suffering from wound botulism during recovery from dysphagia. An age-matched group of healthy subjects served as control group. A self-paced swallowing paradigm was performed and data were analyzed using synthetic aperture magnetometry (SAM. Results The first MEG measurement, carried out when the patient still demonstrated severe dysphagia, revealed strongly decreased activation of the somatosensory cortex but a strong activation of the right insula and marked recruitment of the left posterior parietal cortex (PPC. In the second measurement performed five days later after clinical recovery from dysphagia we found a decreased activation in these two areas and a bilateral cortical activation of the primary and secondary sensorimotor cortex comparable to the results seen in a healthy control group. Conclusion These findings indicate parallel development to normalization of swallowing related cortical activation and clinical recovery from dysphagia and highlight the importance of the insula and the PPC for the central coordination of swallowing. The results suggest that MEG examination of swallowing can reflect short-term changes in patients suffering from neurogenic dysphagia.

  20. Cortical recovery of swallowing function in wound botulism.

    Science.gov (United States)

    Teismann, Inga K; Steinstraeter, Olaf; Warnecke, Tobias; Zimmermann, Julian; Ringelstein, Erich B; Pantev, Christo; Dziewas, Rainer

    2008-05-07

    Botulism is a rare disease caused by intoxication leading to muscle weakness and rapidly progressive dysphagia. With adequate therapy signs of recovery can be observed within several days. In the last few years, brain imaging studies carried out in healthy subjects showed activation of the sensorimotor cortex and the insula during volitional swallowing. However, little is known about cortical changes and compensation mechanisms accompanying swallowing pathology. In this study, we applied whole-head magnetoencephalography (MEG) in order to study changes in cortical activation in a 27-year-old patient suffering from wound botulism during recovery from dysphagia. An age-matched group of healthy subjects served as control group. A self-paced swallowing paradigm was performed and data were analyzed using synthetic aperture magnetometry (SAM). The first MEG measurement, carried out when the patient still demonstrated severe dysphagia, revealed strongly decreased activation of the somatosensory cortex but a strong activation of the right insula and marked recruitment of the left posterior parietal cortex (PPC). In the second measurement performed five days later after clinical recovery from dysphagia we found a decreased activation in these two areas and a bilateral cortical activation of the primary and secondary sensorimotor cortex comparable to the results seen in a healthy control group. These findings indicate parallel development to normalization of swallowing related cortical activation and clinical recovery from dysphagia and highlight the importance of the insula and the PPC for the central coordination of swallowing. The results suggest that MEG examination of swallowing can reflect short-term changes in patients suffering from neurogenic dysphagia.

  1. Focal laminar cortical infarcts following aneurysmal subarachnoid haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Weidauer, Stefan; Lanfermann, Heinrich; Zanella, Friedhelm [University of Frankfurt, Institute of Neuroradiology, Frankfurt (Germany); Vatter, Hartmut; Beck, Juergen; Raabe, Andreas; Seifert, Volker [University of Frankfurt, Department of Neurosurgery, Frankfurt (Germany)

    2008-01-15

    The aim of this prospective study was to analyse small band-like cortical infarcts after subarachnoid haemorrhage (SAH) using magnetic resonance imaging (MRI) with reference to additional digital subtraction angiography (DSA). In a 5-year period between January 2002 and January 2007 10 out of 188 patients with aneurysmal SAH were evaluated (one patient Hunt and Hess grade I, one patient grade II, four patients grade III, two patients grade IV, and two patients grade V). The imaging protocol included serially performed MRI with diffusion- and perfusion-weighted images (DWI/PWI) at three time points after aneurysm treatment, and cerebral vasospasm (CVS) was analysed on follow-up DSA on day 7{+-}3 after SAH. The lesions were located in the frontal lobe (n=10), in the insular cortex (n=3) and in the parietal lobe (n=1). The band-like infarcts occurred after a mean time interval of 5.8 days (range 3-10 days) and showed unexceptional adjacent thick sulcal clots. Seven out of ten patients with cortical infarcts had no or mild CVS, and in the remaining three patients DSA disclosed moderate (n=2) or severe (n=1) CVS. The infarct pattern after aneurysmal SAH includes cortical band-like lesions. In contrast to territorial infarcts or lacunar infarcts in the white matter which develop as a result of moderate or severe proximal and/or distal vasospasm visible on angiography, the cortical band-like lesions adjacent to sulcal clots may also develop without evidence of macroscopic vasospasm, implying a vasospastic reaction of the most distal superficial and intraparenchymal vessels. (orig.)

  2. Entorhinal cortex of the rat: cytoarchitectonic subdivisions and the origin and distribution of cortical efferents.

    Science.gov (United States)

    Insausti, R; Herrero, M T; Witter, M P

    1997-01-01

    The origins and terminations of entorhinal cortical projections in the rat were analyzed in detail with retrograde and anterograde tracing techniques. Retrograde fluorescent tracers were injected in different portions of olfactory, medial frontal (infralimbic and prelimbic areas), lateral frontal (motor area), temporal (auditory), parietal (somatosensory), occipital (visual), cingulate, retrosplenial, insular, and perirhinal cortices. Anterograde tracer injections were placed in various parts of the rat entorhinal cortex to demonstrate the laminar and topographical distribution of the cortical projections of the entorhinal cortex. The retrograde experiments showed that each cortical area explored receives projections from a specific set of entorhinal neurons, limited in number and distribution. By far the most extensive entorhinal projection was directed to the perirhinal cortex. This projection, which arises from all layers, originates throughout the entorhinal cortex, although its major origin is from the more lateral and caudal parts of the entorhinal cortex. Projections to the medial frontal cortex and olfactory structures originate largely in layers II and III of much of the intermediate and medial portions of the entorhinal cortex, although a modest component arises from neurons in layer V of the more caudal parts of the entorhinal cortex. Neurons in layer V of an extremely laterally located strip of entorhinal cortex, positioned along the rhinal fissure, give rise to the projections to lateral frontal (motor), parietal (somatosensory), temporal (auditory), occipital (visual), anterior insular, and cingulate cortices. Neurons in layer V of the most caudal part of the entorhinal cortex originate projections to the retrosplenial cortex. The anterograde experiments confirmed these findings and showed that in general, the terminal fields of the entorhinal-cortical projections were densest in layers I, II, and III, although particularly in the more densely

  3. Cortical thinning in subcortical vascular dementia with negative 11C-PiB PET.

    Science.gov (United States)

    Kim, Chi Hun; Seo, Sang Won; Kim, Geon Ha; Shin, Ji Soo; Cho, Hanna; Noh, Young; Kim, Suk-Hui; Kim, Min Ji; Jeon, Seun; Yoon, Uicheul; Lee, Jong-Min; Oh, Seung Jun; Kim, Jae Seung; Kim, Sung Tae; Lee, Jae-Hong; Na, Duk L

    2012-01-01

    To determine the existence of cortical thinning in subcortical vascular dementia (SVaD) with a negative 11C-Pittsburgh compound B (PiB) positron emission tomography scan and to compare the topography of cortical thinning between PiB-negative SVaD and Alzheimer's disease (AD), we enrolled 24 patients with PiB(-) SVaD, 81 clinically probable AD individuals, and 72 normal cognitive controls. Compared with controls, cortical thinning in PiB(-) SVaD was most profound in the perisylvian area, medial prefrontal area, and posterior cingulate gyri, while the precuneus and medial temporal lobes were relatively spared. When the cortical thickness of AD and PiB(-) SVaD were directly compared, PiB(-) SVaD demonstrated significant cortical thinning in the bilateral inferior frontal, superior temporal gyri, and right medial frontal and orbitofrontal lobes, while AD showed significant cortical thinning in the right medial temporal region. SVaD without amyloid burden may lead to substantial cortical atrophy. Moreover, characteristic topography of cortical thinning in PiB(-) SVaD suggests different mechanisms of cortical thinning in PiB(-) SVaD and AD.

  4. Vulnerability of the medial frontal corticospinal projection accompanies combined lateral frontal and parietal cortex injury in rhesus monkey.

    Science.gov (United States)

    Morecraft, R J; Ge, J; Stilwell-Morecraft, K S; McNeal, D W; Hynes, S M; Pizzimenti, M A; Rotella, D L; Darling, W G

    2015-03-01

    Concurrent damage to the lateral frontal and parietal cortex is common following middle cerebral artery infarction, leading to upper extremity paresis, paresthesia, and sensory loss. Motor recovery is often poor, and the mechanisms that support or impede this process are unclear. Since the medial wall of the cerebral hemisphere is commonly spared following stroke, we investigated the spontaneous long-term (6 and 12 month) effects of lateral frontoparietal injury (F2P2 lesion) on the terminal distribution of the corticospinal projection (CSP) from intact, ipsilesional supplementary motor cortex (M2) at spinal levels C5 to T1. Isolated injury to the frontoparietal arm/hand region resulted in a significant loss of contralateral corticospinal boutons from M2 compared with controls. Specifically, reductions occurred in the medial and lateral parts of lamina VII and the dorsal quadrants of lamina IX. There were no statistical differences in the ipsilateral CSP. Contrary to isolated lateral frontal motor injury (F2 lesion), which results in substantial increases in contralateral M2 labeling in laminae VII and IX (McNeal et al. [2010] J. Comp. Neurol. 518:586-621), the added effect of adjacent parietal cortex injury to the frontal motor lesion (F2P2 lesion) not only impedes a favorable compensatory neuroplastic response but results in a substantial loss of M2 CSP terminals. This dramatic reversal of the CSP response suggests a critical trophic role for cortical somatosensory influence on spared ipsilesional frontal corticospinal projections, and that restoration of a favorable compensatory response will require therapeutic intervention. © 2014 Wiley Periodicals, Inc.

  5. Assessment of quantitative cortical biomarkers in the developing brain of preterm infants

    Science.gov (United States)

    Moeskops, Pim; Benders, Manon J. N. L.; Pearlman, Paul C.; Kersbergen, Karina J.; Leemans, Alexander; Viergever, Max A.; Išgum, Ivana

    2013-02-01

    The cerebral cortex rapidly develops its folding during the second and third trimester of pregnancy. In preterm birth, this growth might be disrupted and influence neurodevelopment. The aim of this work is to extract quantitative biomarkers describing the cortex and evaluate them on a set of preterm infants without brain pathology. For this study, a set of 19 preterm - but otherwise healthy - infants scanned coronally with 3T MRI at the postmenstrual age of 30 weeks were selected. In ten patients (test set), the gray and white matter were manually annotated by an expert on the T2-weighted scans. Manual segmentations were used to extract cortical volume, surface area, thickness, and curvature using voxel-based methods. To compute these biomarkers per region in every patient, a template brain image has been generated by iterative registration and averaging of the scans of the remaining nine patients. This template has been manually divided in eight regions, and is transformed to every test image using elastic registration. In the results, gray and white matter volumes and cortical surface area appear symmetric between hemispheres, but small regional differences are visible. Cortical thickness seems slightly higher in the right parietal lobe than in other regions. The parietal lobes exhibit a higher global curvature, indicating more complex folding compared to other regions. The proposed approach can potentially - together with an automatic segmentation algorithm - be applied as a tool to assist in early diagnosis of abnormalities and prediction of the development of the cognitive abilities of these children.

  6. Classification of Single Normal and Alzheimer's Disease Individuals from Cortical Sources of Resting State EEG Rhythms

    Science.gov (United States)

    Babiloni, Claudio; Triggiani, Antonio I.; Lizio, Roberta; Cordone, Susanna; Tattoli, Giacomo; Bevilacqua, Vitoantonio; Soricelli, Andrea; Ferri, Raffaele; Nobili, Flavio; Gesualdo, Loreto; Millán-Calenti, José C.; Buján, Ana; Tortelli, Rosanna; Cardinali, Valentina; Barulli, Maria Rosaria; Giannini, Antonio; Spagnolo, Pantaleo; Armenise, Silvia; Buenza, Grazia; Scianatico, Gaetano; Logroscino, Giancarlo; Frisoni, Giovanni B.; del Percio, Claudio

    2016-01-01

    Previous studies have shown abnormal power and functional connectivity of resting state electroencephalographic (EEG) rhythms in groups of Alzheimer's disease (AD) compared to healthy elderly (Nold) subjects. Here we tested the best classification rate of 120 AD patients and 100 matched Nold subjects using EEG markers based on cortical sources of power and functional connectivity of these rhythms. EEG data were recorded during resting state eyes-closed condition. Exact low-resolution brain electromagnetic tomography (eLORETA) estimated the power and functional connectivity of cortical sources in frontal, central, parietal, occipital, temporal, and limbic regions. Delta (2–4 Hz), theta (4–8 Hz), alpha 1 (8–10.5 Hz), alpha 2 (10.5–13 Hz), beta 1 (13–20 Hz), beta 2 (20–30 Hz), and gamma (30–40 Hz) were the frequency bands of interest. The classification rates of interest were those with an area under the receiver operating characteristic curve (AUROC) higher than 0.7 as a threshold for a moderate classification rate (i.e., 70%). Results showed that the following EEG markers overcame this threshold: (i) central, parietal, occipital, temporal, and limbic delta/alpha 1 current density; (ii) central, parietal, occipital temporal, and limbic delta/alpha 2 current density; (iii) frontal theta/alpha 1 current density; (iv) occipital delta/alpha 1 inter-hemispherical connectivity; (v) occipital-temporal theta/alpha 1 right and left intra-hemispherical connectivity; and (vi) parietal-limbic alpha 1 right intra-hemispherical connectivity. Occipital delta/alpha 1 current density showed the best classification rate (sensitivity of 73.3%, specificity of 78%, accuracy of 75.5%, and AUROC of 82%). These results suggest that EEG source markers can classify Nold and AD individuals with a moderate classification rate higher than 80%. PMID:26941594

  7. Parietal Epithelial Cell Activation Marker in Early Recurrence of FSGS in the Transplant

    NARCIS (Netherlands)

    Fatima, H.; Moeller, M.J.; Smeets, B.; Yang, H.C.; D'Agati, V.D.; Alpers, C.E.; Fogo, A.B.

    2012-01-01

    BACKGROUND AND OBJECTIVES: Podocyte loss is key in glomerulosclerosis. Activated parietal epithelial cells are proposed to contribute to pathogenesis of glomerulosclerosis and may serve as stem cells that can transition to podocytes. CD44 is a marker for activated parietal epithelial cells. This stu

  8. Induction of motor associative plasticity in the posterior parietal cortex-primary motor network

    DEFF Research Database (Denmark)

    Chao, Chi-Chao; Karabanov, Anke Ninija; Paine, Rainer

    2015-01-01

    There is anatomical and functional connectivity between the primary motor cortex (M1) and posterior parietal cortex (PPC) that plays a role in sensorimotor integration. In this study, we applied corticocortical paired-associative stimuli to ipsilateral PPC and M1 (parietal ccPAS) in healthy right...

  9. Mapping different intra-hemispheric parietal-motor networks using twin Coil TMS

    DEFF Research Database (Denmark)

    Karabanov, Anke Ninija; Chao, Chi-Chao; Paine, Rainer

    2013-01-01

    Accumulating evidence suggests anatomical and functional differences in connectivity between the anterior and posterior parts of the inferior-parietal lobule (IPL) and the frontal motor areas.......Accumulating evidence suggests anatomical and functional differences in connectivity between the anterior and posterior parts of the inferior-parietal lobule (IPL) and the frontal motor areas....

  10. Dynamic CT Features of a hemangioma originating from the parietal pleura: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Won Kyung; Park, Jai Soung; Park, Sang Hyun; Cha, Jang Gyu; Shin, Hwa Kyoon; Koh, Eun Suk [Soonchunhyang Univ. Bucheon Hospital/Soonchunhyang Univ. College of Medicine, Bucheon (Korea, Republic of)

    2012-06-15

    A pleural hemangioma is an extremely rare disease. Few studies have reported on the radiologic appearance of chest wall hemangioma, especially originating from the parietal pleura. We describe a 45 year old female patient with a soft tissue mass in the parietal pleura showing centripetal enhancement on dynamic CT. The patient underwent surgery and the pathologic examination confirmed the presence of a capillary hemangioma.

  11. The Contribution of the Inferior Parietal Cortex to Spoken Language Production

    Science.gov (United States)

    Geranmayeh, Fatemeh; Brownsett, Sonia L. E.; Leech, Robert; Beckmann, Christian F.; Woodhead, Zoe; Wise, Richard J. S.

    2012-01-01

    This functional MRI study investigated the involvement of the left inferior parietal cortex (IPC) in spoken language production (Speech). Its role has been apparent in some studies but not others, and is not convincingly supported by clinical studies as they rarely include cases with lesions confined to the parietal lobe. We compared Speech with…

  12. The Role of Right and Left Parietal Lobes in the Conceptual Processing of Numbers

    Science.gov (United States)

    Cappelletti, Marinella; Lee, Hwee Ling; Freeman, Elliot D.; Price, Cathy J.

    2010-01-01

    Neuropsychological and functional imaging studies have associated the conceptual processing of numbers with bilateral parietal regions (including intraparietal sulcus). However, the processes driving these effects remain unclear because both left and right posterior parietal regions are activated by many other conceptual, perceptual, attention,…

  13. 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.

  14. 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.

  15. Role of parietal regions in episodic memory retrieval: the dual attentional processes hypothesis.

    Science.gov (United States)

    Cabeza, Roberto

    2008-01-01

    Although parietal cortex is frequently activated during episodic memory retrieval, damage to this region does not markedly impair episodic memory. To account for these and other findings, a new dual attentional processes (DAP) hypothesis is proposed. According to this hypothesis, dorsal parietal cortex (DPC) contributes top-down attentional processes guided by retrieval goals, whereas ventral parietal cortex (VPC) contributes bottom-up attentional processes captured by the retrieval output. Consistent with this hypothesis, DPC activity increases with retrieval effort whereas VPC activity increases with confidence in old and new responses. The DAP hypothesis can also account for the overlap of parietal activations across different cognitive domains and for opposing effects of parietal activity on encoding vs. retrieval. Finally, the DAP hypothesis explains why VPC lesions yield a memory neglect syndrome: a deficit in spontaneously reporting relevant memory details but not in accessing the same details when guided by specific questions.

  16. Brain cortical thickness in male adolescents with serious substance use and conduct problems

    Science.gov (United States)

    Chumachenko, Serhiy Y.; Sakai, Joseph T.; Dalwani, Manish S.; Mikulich-Gilbertson, Susan K.; Dunn, Robin; Tanabe, Jody; Young, Susan; McWilliams, Shannon K.; Banich, Marie T.; Crowley, Thomas J.

    2016-01-01

    Background Adolescents with substance use disorder (SUD) and conduct problems exhibit high levels of impulsivity and poor self-control. Limited work to date tests for brain cortical thickness differences in these youths. Objectives To investigate differences in cortical thickness between adolescents with substance use and conduct problems and controls. Methods We recruited 25 male adolescents with SUD, and 19 male adolescent controls, and completed structural 3T magnetic resonance brain imaging. Using the surface-based morphometry software FreeSurfer, we completed region-of-interest (ROI) analyses for group cortical thickness differences in left, and separately right, inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and insula. Using FreeSurfer, we completed whole-cerebrum analyses of group differences in cortical thickness. Results Versus controls, the SUD group showed no cortical thickness differences in ROI analyses. Controlling for age and IQ, no regions with cortical thickness differences were found using whole-cerebrum analyses (though secondary analyses co-varying IQ and whole-cerebrum cortical thickness yielded a between-group cortical thickness difference in the left posterior cingulate/precuneus). Secondary findings showed that the SUD group, relative to controls, demonstrated significantly less right>left asymmetry in IFG, had weaker insular-to-whole-cerebrum cortical thickness correlations, and showed a positive association between conduct disorder symptom count and cortical thickness in a superior temporal gyrus cluster. Conclusion Functional group differences may reflect a more nuanced cortical morphometric difference than ROI cortical thickness. Further investigation of morphometric differences is needed. If replicable findings can be established, they may aid in developing improved diagnostic or more targeted treatment approaches. PMID:26337200

  17. Brain cortical thickness in male adolescents with serious substance use and conduct problems.

    Science.gov (United States)

    Chumachenko, Serhiy Y; Sakai, Joseph T; Dalwani, Manish S; Mikulich-Gilbertson, Susan K; Dunn, Robin; Tanabe, Jody; Young, Susan; McWilliams, Shannon K; Banich, Marie T; Crowley, Thomas J

    2015-01-01

    Adolescents with substance use disorder (SUD) and conduct problems exhibit high levels of impulsivity and poor self-control. Limited work to date tests for brain cortical thickness differences in these youths. To investigate differences in cortical thickness between adolescents with substance use and conduct problems and controls. We recruited 25 male adolescents with SUD, and 19 male adolescent controls, and completed structural 3T magnetic resonance brain imaging. Using the surface-based morphometry software FreeSurfer, we completed region-of-interest (ROI) analyses for group cortical thickness differences in left, and separately right, inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and insula. Using FreeSurfer, we completed whole-cerebrum analyses of group differences in cortical thickness. Versus controls, the SUD group showed no cortical thickness differences in ROI analyses. Controlling for age and IQ, no regions with cortical thickness differences were found using whole-cerebrum analyses (though secondary analyses co-varying IQ and whole-cerebrum cortical thickness yielded a between-group cortical thickness difference in the left posterior cingulate/precuneus). Secondary findings showed that the SUD group, relative to controls, demonstrated significantly less right > left asymmetry in IFG, had weaker insular-to-whole-cerebrum cortical thickness correlations, and showed a positive association between conduct disorder symptom count and cortical thickness in a superior temporal gyrus cluster. Functional group differences may reflect a more nuanced cortical morphometric difference than ROI cortical thickness. Further investigation of morphometric differences is needed. If replicable findings can be established, they may aid in developing improved diagnostic or more targeted treatment approaches.

  18. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. 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