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Sample records for inferior parietal lobule

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

    PubMed

    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

  2. Spatial selectivity in the temporoparietal junction, inferior frontal sulcus, and inferior parietal lobule

    PubMed Central

    Hansen, Kathleen A.; Chu, Carlton; Dickinson, Annelise; Pye, Brandon; Weller, J. Patrick; Ungerleider, Leslie G.

    2015-01-01

    Spatial selectivity, as measured by functional magnetic resonance imaging (fMRI) activity patterns that vary consistently with the location of visual stimuli, has been documented in many human brain regions, notably the occipital visual cortex and the frontal and parietal regions that are active during endogenous, goal-directed attention. We hypothesized that spatial selectivity also exists in regions that are active during exogenous, stimulus-driven attention. To test this hypothesis, we acquired fMRI data while subjects maintained passive fixation. At jittered time intervals, a briefly presented wedge-shaped array of rapidly expanding circles appeared at one of three contralateral or one of three ipsilateral locations. Positive fMRI activations were identified in multiple brain regions commonly associated with exogenous attention, including the temporoparietal junction, the inferior parietal lobule, and the inferior frontal sulcus. These activations were not organized as a map across the cortical surface. However, multivoxel pattern analysis of the fMRI activity correctly classified every pair of stimulus locations, demonstrating that patterns of fMRI activity were correlated with spatial location. These observations held for both contralateral and ipsilateral stimulus pairs as well as for stimuli of different textures (radial checkerboard) and shapes (squares and rings). Permutation testing verified that the obtained accuracies were not due to systematic biases and demonstrated that the findings were statistically significant. PMID:26382006

  3. Motor imagery-based skill acquisition disrupted following rTMS of the inferior parietal lobule.

    PubMed

    Kraeutner, Sarah N; Keeler, Laura T; Boe, Shaun G

    2016-02-01

    Motor imagery (MI), the mental rehearsal of motor tasks, has promise as a therapy in post-stroke rehabilitation. The potential effectiveness of MI is attributed to the facilitation of plasticity in numerous brain regions akin to those recruited for physical practice. It is suggested, however, that MI relies more heavily on regions commonly affected post-stroke, including left hemisphere parietal regions involved in visuospatial processes. However, the impact of parietal damage on MI-based skill acquisition that underlies rehabilitation remains unclear. Here, we examine the contribution of the left inferior parietal lobule (IPL) to MI using inhibitory transcranial magnetic stimulation (TMS) and an MI-based implicit sequence learning (ISL) paradigm. Participants (N = 27) completed the MI-based ISL paradigm after receiving continuous theta burst stimulation to the left IPL (TMS), or with the coil angled away from the scalp (sham). Reaction time differences (dRT) and effect sizes between implicit and random sequences assessed success of MI-based learning. Mean dRT for the sham group was 36.1 ± 28.2 ms (d = 0.71). Mean dRT in the TMS group was 7.7 ± 38.5 ms (d = 0.11). These results indicate that inhibition of the left IPL impaired MI-based learning. We conclude that the IPL and likely the visuospatial processes it mediates are critical for MI performance and thus MI-based skill acquisition or learning. Ultimately, these findings have implications for the use of MI in post-stroke rehabilitation.

  4. Morphometric characteristics of neuropeptide Y immunoreactive neurons in cortex of human inferior parietal lobule.

    PubMed

    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. Quantitative phosphoproteomic analyses of the inferior parietal lobule from three different pathological stages of Alzheimer's disease.

    PubMed

    Triplett, Judy C; Swomley, Aaron M; Cai, Jian; Klein, Jon B; Butterfield, D Allan

    2016-01-01

    Alzheimer's disease (AD), the most common age-related neurodegenerative disorder, is clinically characterized by progressive neuronal loss resulting in loss of memory and dementia. AD is histopathologically characterized by the extensive distribution of senile plaques and neurofibrillary tangles, and synapse loss. Amnestic mild cognitive impairment (MCI) is generally accepted to be an early stage of AD. MCI subjects have pathology and symptoms that fall on the scale intermediately between 'normal' cognition with little or no pathology and AD. A rare number of individuals, who exhibit normal cognition on psychometric tests but whose brains show widespread postmortem AD pathology, are classified as 'asymptomatic' or 'preclinical' AD (PCAD). In this study, we evaluated changes in protein phosphorylation states in the inferior parietal lobule of subjects with AD, MCI, PCAD, and control brain using a 2-D PAGE proteomics approach in conjunction with Pro-Q Diamond phosphoprotein staining. Statistically significant changes in phosphorylation levels were found in 19 proteins involved in energy metabolism, neuronal plasticity, signal transduction, and oxidative stress response. Changes in the disease state phosphoproteome may provide insights into underlying mechanisms for the preservation of memory with expansive AD pathology in PCAD and the progressive memory loss in amnestic MCI that escalates to the dementia and the characteristic pathology of AD brain.

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

    PubMed Central

    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

  7. Functional topography of the right inferior parietal lobule structured by anatomical connectivity profiles.

    PubMed

    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

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

    PubMed

    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.

  9. The role of the left inferior parietal lobule in second language learning: An intensive language training fMRI study.

    PubMed

    Barbeau, Elise B; Chai, Xiaoqian J; Chen, Jen-Kai; Soles, Jennika; Berken, Jonathan; Baum, Shari; Watkins, Kate E; Klein, Denise

    2016-10-07

    Research to date suggests that second language acquisition results in functional and structural changes in the bilingual brain, however, in what way and how quickly these changes occur remains unclear. To address these questions, we studied fourteen English-speaking monolingual adults enrolled in a 12-week intensive French language-training program in Montreal. Using functional MRI, we investigated the neural changes associated with new language acquisition. The participants were scanned before the start of the immersion program and at the end of the 12 weeks. The fMRI scan aimed to investigate the brain regions recruited in a sentence reading task both in English, their first language (L1), and in French, their second language (L2). For the L1, fMRI patterns did not change from Time 1 to Time 2, while for the L2, the brain response changed between Time 1 and Time 2 in language-related areas. Of note, for the L2, there was higher activation at Time 2 compared to Time 1 in the left inferior parietal lobule (IPL) including the supramarginal gyrus. At Time 2 this higher activation in the IPL correlated with faster L2 reading speed. Moreover, higher activation in the left IPL at Time 1 predicted improvement in L2 reading speed from Time 1 to Time 2. Our results suggest that learning-induced plasticity occurred as early as 12 weeks into immersive second-language training, and that the IPL appears to play a special role in language learning.

  10. White matter volume in the brainstem and inferior parietal lobule is related to motor performance in children with autism spectrum disorder: A voxel-based morphometry study.

    PubMed

    Hanaie, Ryuzo; Mohri, Ikuko; Kagitani-Shimono, Kuriko; Tachibana, Masaya; Matsuzaki, Junko; Hirata, Ikuko; Nagatani, Fumiyo; Watanabe, Yoshiyuki; Fujita, Norihiko; Taniike, Masako

    2016-09-01

    Many studies have reported poor motor performance in autism spectrum disorder (ASD); however, the underlying brain mechanisms remain unclear. Recent neuroimaging studies have suggested that abnormalities of the white matter (WM) are related to the features of ASD. In this study, we used voxel-based morphometry (VBM) to investigate which WM regions correlate with motor performance in children with ASD, and whether the WM volume in those brain regions differed between children with ASD and typically developing (TD) children. The subjects included 19 children with ASD and 20 TD controls. Motor performance was assessed using the Movement Assessment Battery for Children 2 (M-ABC 2). Children with ASD showed poorer motor performance than did the controls. There was a significant positive correlation between the total test score on the M-ABC 2 and the volume of WM in the brainstem and WM adjacent to the left supramarginal gyrus (SMG). In addition, compared with the TD controls, children with ASD had a decreased volume of WM in the brainstem and adjacent to the left intraparietal sulcus, which is close to the SMG. These findings suggest that structural changes in the WM in the brainstem and left inferior parietal lobule may contribute to poor motor performance in children with ASD. Autism Res 2016, 9: 981-992. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

  11. Correspondent Functional Topography of the Human Left Inferior Parietal Lobule at Rest and Under Task Revealed Using Resting-State fMRI and Coactivation Based Parcellation.

    PubMed

    Wang, Jiaojian; Xie, Sangma; Guo, Xin; Becker, Benjamin; Fox, Peter T; Eickhoff, Simon B; Jiang, Tianzi

    2017-03-01

    The human left inferior parietal lobule (LIPL) plays a pivotal role in many cognitive functions and is an important node in the default mode network (DMN). Although many previous studies have proposed different parcellation schemes for the LIPL, the detailed functional organization of the LIPL and the exact correspondence between the DMN and LIPL subregions remain unclear. Mounting evidence indicates that spontaneous fluctuations in the brain are strongly associated with cognitive performance at the behavioral level. However, whether a consistent functional topographic organization of the LIPL during rest and under task can be revealed remains unknown. Here, they used resting-state functional connectivity (RSFC) and task-related coactivation patterns separately to parcellate the LIPL and identified seven subregions. Four subregions were located in the supramarginal gyrus (SMG) and three subregions were located in the angular gyrus (AG). The subregion-specific networks and functional characterization revealed that the four anterior subregions were found to be primarily involved in sensorimotor processing, movement imagination and inhibitory control, audition perception and speech processing, and social cognition, whereas the three posterior subregions were mainly involved in episodic memory, semantic processing, and spatial cognition. The results revealed a detailed functional organization of the LIPL and suggested that the LIPL is a functionally heterogeneous area. In addition, the present study demonstrated that the functional architecture of the LIPL during rest corresponds with that found in task processing. Hum Brain Mapp 38:1659-1675, 2017. © 2017 Wiley Periodicals, Inc.

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

    PubMed Central

    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. PMID:27047351

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

    PubMed

    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.

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

    PubMed

    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.

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

    ERIC Educational Resources Information Center

    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…

  16. Audio-visual multisensory integration in superior parietal lobule revealed by human intracranial recordings.

    PubMed

    Molholm, Sophie; Sehatpour, Pejman; Mehta, Ashesh D; Shpaner, Marina; Gomez-Ramirez, Manuel; Ortigue, Stephanie; Dyke, Jonathan P; Schwartz, Theodore H; Foxe, John J

    2006-08-01

    Intracranial recordings from three human subjects provide the first direct electrophysiological evidence for audio-visual multisensory processing in the human superior parietal lobule (SPL). Auditory and visual sensory inputs project to the same highly localized region of the parietal cortex with auditory inputs arriving considerably earlier (30 ms) than visual inputs (75 ms). Multisensory integration processes in this region were assessed by comparing the response to simultaneous audio-visual stimulation with the algebraic sum of responses to the constituent auditory and visual unisensory stimulus conditions. Significant integration effects were seen with almost identical morphology across the three subjects, beginning between 120 and 160 ms. These results are discussed in the context of the role of SPL in supramodal spatial attention and sensory-motor transformations.

  17. The anterior superior parietal lobule and its interactions with language and motor areas during writing.

    PubMed

    Segal, Emily; Petrides, Michael

    2012-01-01

    Past neuroimaging studies of writing demonstrate activation foci in several regions of the posterior parietal cortex (PPC). The present study aimed to dissociate the role of the superior parietal lobule (SPL) from the other PPC regions using functional magnetic resonance imaging (fMRI) and functional connectivity. First, parametric event-related fMRI permitted the categorical comparison of experimental writing conditions with control conditions that were carefully chosen to match the experimental conditions in terms of variables extraneous to the motor act of writing, such as visual stimulus characteristics, and generating and retrieving verbal information. A selective focus of increased activation in the PPC restricted to the rostral part of the SPL (area PE) in the left hemisphere was demonstrated. Subsequently, functional connectivity analysis showed that area PE flexibly interacts with different language areas depending on the linguistic demands of the writing task. Activity in area PE correlates with the left angular gyrus, a region implicated in reading, when the writing is in response to words that are read; in sharp contrast, when the writing is in response to pictured objects, then area PE correlates with the supramarginal gyrus, a region involved in the articulatory and phonological loop, as well as with prefrontal regions that are involved in the retrieval and selection of semantic information. The results suggest that area PE serves as a critical interface between posterior cortical regions in the left hemisphere involved in language processing and the central motor and sensory regions that are directly involved in the control of movement.

  18. Changes in effective connectivity of human superior parietal lobule under multisensory and unisensory stimulation.

    PubMed

    Moran, R J; Molholm, S; Reilly, R B; Foxe, J J

    2008-05-01

    Previous event-related potential (ERP) studies have identified the superior parietal lobule (SPL) as actively multisensory. This study compares effective, or contextually active, connections to this region under unisensory and multisensory conditions. Effective connectivity, the influence of one brain region over another, during unisensory visual, unisensory auditory and multisensory audiovisual stimulation was investigated. ERPs were recorded from subdural electrodes placed over the parietal lobe of three patients while they conducted a rapid reaction-time task. A generative model of interacting neuronal ensembles for ERPs was inverted in a scheme allowing investigation of the connections from and to the SPL, a multisensory processing area. Important features of the ensemble model include inhibitory and excitatory feedback connections to pyramidal cells and extrinsic input to the stellate cell pool, with extrinsic forward and backward connections delineated by laminar connection differences between ensembles. The framework embeds the SPL in a plausible connection of distinct neuronal ensembles mirroring the integrated brain regions involved in the response task. Bayesian model comparison was used to test competing feed-forward and feed-backward models of how the electrophysiological data were generated. Comparisons were performed between multisensory and unisensory data. Findings from three patients show differences in summed unisensory and multisensory ERPs that can be accounted for by a mediation of both forward and backward connections to the SPL. In particular, a negative gain in all forward and backward connections to the SPL from other regions was observed during the period of multisensory integration, while a positive gain was observed for forward projections that arise from the SPL.

  19. Convergent Functional Architecture of the Superior Parietal Lobule Unraveled with Multimodal Neuroimaging Approaches

    PubMed Central

    Wang, Jiaojian; Yang, Yong; Fan, Lingzhong; Xu, Jinping; Li, Changhai; Liu, Yong; Fox, Peter T.; Eickhoff, Simon B.; Yu, Chunshui; Jiang, Tianzi

    2014-01-01

    The superior parietal lobule (SPL) plays a pivotal role in many cognitive, perceptive and motor-related processes. This implies that a mosaic of distinct functional and structural subregions may exist in this area. Recent studies have demonstrated that the ongoing spontaneous fluctuations in the brain at rest are highly structured and, like co-activation patterns, reflect the integration of cortical locations into long-distance networks. This suggests that the internal differentiation of a complex brain region may be revealed by interaction-patterns that are reflected in different neuroimaging modalities. On the basis of this perspective, we aimed to identify a convergent functional organization of the SPL using multimodal neuroimaging approaches. The SPL was first parcellated based on its structural connections as well as on its resting-state connectivity and coactivation patterns. Then, post-hoc functional characterizations and connectivity analyses were performed for each subregion. The three types of connectivity-based parcellations consistently identified five subregions in the SPL of each hemisphere. The two anterior subregions were found to be primarily involved in action processes and in visually guided visuomotor functions, whereas the three posterior subregions were primarily associated with visual perception, spatial cognition, reasoning, working memory, and attention. This parcellation scheme for the SPL was further supported by revealing distinct connectivity patterns for each sub-region in all the employed modalities. These results thus indicate a convergent functional architecture of the SPL that can be revealed based on different types of connectivity and is reflected by different functions and interactions. PMID:25181023

  20. High frequency rTMS over the left parietal lobule increases non-word reading accuracy.

    PubMed

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

    2012-09-01

    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 (IPL), which operates in phonological computation. This study aimed to clarify the specific contribution of IPL and STG to reading aloud and to evaluate the possibility of modulating healthy participants' task performance using high frequency repetitive TMS (hf-rTMS). The main finding is that hf-rTMS over the left IPL improves non-word reading accuracy (fewer errors), whereas hf-rTMS over the right STG selectively decreases text-reading accuracy (more errors). These results confirm the prevalent role of the left IPL in grapheme-to-phoneme conversion. The non-word reading improvement after Left-IPL stimulation provide a direct link between left IPL activation and advantages in sublexical procedures, mainly involved in non-word reading. Results indicate also the specific involvement of STG in reading morphologically complex words and in processing the representation of the text. The text reading impairment after stimulation of the right STG can be interpreted in light of an inhibitory influence on the homologous area. In sum, data document that hf-rTMS is effective in modulating the reading accuracy of expert readers and that the modulation is task related and site specific. These findings suggest new perspectives for the treatment of reading disorders.

  1. Differential contributions of the superior and inferior parietal cortex to feedback versus feedforward control of tools

    PubMed Central

    Macuga, Kristen L.; Frey, Scott H.

    2016-01-01

    Damage to the superior and/or inferior parietal lobules (SPL, IPL) (Sirigu et al., 1996) or cerebellum (Grealy and Lee, 2011) can selectively disrupt motor imagery, motivating the hypothesis that these regions participate in predictive (i.e., feedforward) control. If so, then the SPL, IPL, and cerebellum should show greater activity as the demands on feedforward control increase from visually-guided execution (closed-loop) to execution without visual feedback (open-loop) to motor imagery. Using fMRI and a Fitts’ reciprocal aiming task with tools directed at targets in far space, we found that the SPL and cerebellum exhibited greater activity during closed-loop control. Conversely, open-loop and imagery conditions were associated with increased activity within the IPL and prefrontal areas. These results are consistent with a superior-to-inferior gradient in the representation of feedback-to-feedforward control within the posterior parietal cortex. Additionally, the anterior SPL displayed greater activity when aiming movements were performed with a stick vs. laser pointer. This may suggest that it is involved in the remapping of far into near (reachable) space (Maravita and Iriki, 2004), or in distalization of the end-effector from hand to stick (Arbib et al., 2009). PMID:24473100

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

    PubMed

    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.

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

    PubMed

    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.

  4. The Contribution of the Inferior Parietal Cortex to Spoken Language Production

    ERIC Educational Resources Information Center

    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…

  5. Sensorimotor integration for speech motor learning involves the inferior parietal cortex.

    PubMed

    Shum, Mamie; Shiller, Douglas M; Baum, Shari R; Gracco, Vincent L

    2011-12-01

    Sensorimotor integration is important for motor learning. The inferior parietal lobe, through its connections with the frontal lobe and cerebellum, has been associated with multisensory integration and sensorimotor adaptation for motor behaviors other than speech. In the present study, the contribution of the inferior parietal cortex to speech motor learning was evaluated using repetitive transcranial magnetic stimulation (rTMS) prior to a speech motor adaptation task. Subjects' auditory feedback was altered in a manner consistent with the auditory consequences of an unintended change in tongue position during speech production, and adaptation performance was used to evaluate sensorimotor plasticity and short-term learning. Prior to the feedback alteration, rTMS or sham stimulation was applied over the left supramarginal gyrus (SMG). Subjects who underwent the sham stimulation exhibited a robust adaptive response to the feedback alteration whereas subjects who underwent rTMS exhibited a diminished adaptive response. The results suggest that the inferior parietal region, in and around SMG, plays a role in sensorimotor adaptation for speech. The interconnections of the inferior parietal cortex with inferior frontal cortex, cerebellum and primary sensory areas suggest that this region may be an important component in learning and adapting sensorimotor patterns for speech.

  6. Atrophy of the Parietal Lobe in Preclinical Dementia

    ERIC Educational Resources Information Center

    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…

  7. 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

    NASA Astrophysics Data System (ADS)

    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.

  8. Developmental changes in mental arithmetic: evidence for increased functional specialization in the left inferior parietal cortex.

    PubMed

    Rivera, S M; Reiss, A L; Eckert, M A; Menon, V

    2005-11-01

    Arithmetic reasoning is arguably one of the most important cognitive skills a child must master. Here we examine neurodevelopmental changes in mental arithmetic. Subjects (ages 8-19 years) viewed arithmetic equations and were asked to judge whether the results were correct or incorrect. During two-operand addition or subtraction trials, for which accuracy was comparable across age, older subjects showed greater activation in the left parietal cortex, along the supramarginal gyrus and adjoining anterior intra-parietal sulcus as well as the left lateral occipital temporal cortex. These age-related changes were not associated with alterations in gray matter density, and provide novel evidence for increased functional maturation with age. By contrast, younger subjects showed greater activation in the prefrontal cortex, including the dorsolateral and ventrolateral prefrontal cortex and the anterior cingulate cortex, suggesting that they require comparatively more working memory and attentional resources to achieve similar levels of mental arithmetic performance. Younger subjects also showed greater activation of the hippocampus and dorsal basal ganglia, reflecting the greater demands placed on both declarative and procedural memory systems. Our findings provide evidence for a process of increased functional specialization of the left inferior parietal cortex in mental arithmetic, a process that is accompanied by decreased dependence on memory and attentional resources with development.

  9. The left inferior parietal lobe represents stored hand-postures for object use and action prediction.

    PubMed

    van Elk, Michiel

    2014-01-01

    Action semantics enables us to plan actions with objects and to predict others' object-directed actions as well. Previous studies have suggested that action semantics are represented in a fronto-parietal action network that has also been implicated to play a role in action observation. In the present fMRI study it was investigated how activity within this network changes as a function of the predictability of an action involving multiple objects and requiring the use of action semantics. Participants performed an action prediction task in which they were required to anticipate the use of a centrally presented object that could be moved to an associated target object (e.g., hammer-nail). The availability of actor information (i.e., presenting a hand grasping the central object) and the number of possible target objects (i.e., 0, 1, or 2 target objects) were independently manipulated, resulting in different levels of predictability. It was found that making an action prediction based on actor information resulted in an increased activation in the extrastriate body area (EBA) and the fronto-parietal action observation network (AON). Predicting actions involving a target object resulted in increased activation in the bilateral IPL and frontal motor areas. Within the AON, activity in the left inferior parietal lobe (IPL) and the left premotor cortex (PMC) increased as a function of the level of action predictability. Together these findings suggest that the left IPL represents stored hand-postures that can be used for planning object-directed actions and for predicting other's actions as well.

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

    PubMed

    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.

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

    PubMed Central

    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

  12. USING ACTION UNDERSTANDING TO UNDERSTAND THE LEFT INFERIOR PARIETAL CORTEX IN THE HUMAN BRAIN

    PubMed Central

    Passingham, RE; Chung, A; Goparaju, B; Cowey, A; Vaina, LM

    2015-01-01

    In an fMRI study we tried to establish whether the areas in the human brain that are involved in the understanding of actions are homologous with the inferior parietal cortex (area PFG) in macaque monkeys. Cells have been described in area PFG that discharge differentially depending upon whether the observer sees food being brought to the mouth or a small object being put in a container. In our study the observers saw videos in which the use of different objects was demonstrated in pantomime; and after viewing the videos, the subject had to pick the object that was appropriate to the pantomime. We found a cluster of activated voxels in parietal areas PFop and PFt and this cluster was greater in the left hemisphere than in the right. We suggest a mechanism that could account for this asymmetry, relate our results to handedness and suggest that they shed light on the human syndrome of apraxia. Finally, we suggest that during the evolution of the hominids, this same pantomime mechanism could have been used to ‘name’ or request objects. PMID:25086203

  13. Functional heterogeneity of inferior parietal cortex during mathematical cognition assessed with cytoarchitectonic probability maps.

    PubMed

    Wu, S S; Chang, T T; Majid, A; Caspers, S; Eickhoff, S B; Menon, V

    2009-12-01

    Although the inferior parietal cortex (IPC) has been consistently implicated in mathematical cognition, the functional roles of its subdivisions are poorly understood. We address this problem using probabilistic cytoarchitectonic maps of IPC subdivisions intraparietal sulcus (IPS), angular gyrus (AG), and supramarginal gyrus. We quantified IPC responses relative to task difficulty and individual differences in task proficiency during mental arithmetic (MA) tasks performed with Arabic (MA-A) and Roman (MA-R) numerals. The 2 tasks showed similar levels of activation in 3 distinct IPS areas, hIP1, hIP2, and hIP3, suggesting their obligatory role in MA. Both AG areas, PGa and PGp, were strongly deactivated in both tasks, with stronger deactivations in posterior area PGp. Compared with the more difficult MA-R task, the MA-A task showed greater responses in both AG areas, but this effect was driven by less deactivation in the MA-A task. AG deactivations showed prominent overlap with lateral parietal nodes of the default mode network, suggesting a nonspecific role in MA. In both tasks, greater bilateral AG deactivation was associated with poorer performance. Our findings suggest a close link between IPC structure and function and they provide new evidence for behaviorally salient functional heterogeneity within the IPC during mathematical cognition.

  14. How do we infer others' goals from non-stereotypic actions? The outcome of context-sensitive inferential processing in right inferior parietal and posterior temporal cortex.

    PubMed

    Liepelt, Roman; Von Cramon, D Yves; Brass, Marcel

    2008-12-01

    Humans permanently monitor others' behaviour and reason about their goals and intentions. Recent studies provided evidence suggesting that a very simple mechanism might underlie these functions. When observing stereotypic actions of others, goal inference seems to work through internal simulation of these actions in the self. However, less is known about the functional mechanisms and brain areas that are involved in inferring goals from others' actions when these actions are not stereotypic. Here we investigated the neural processes that are involved in goal inference processing of simple, non-stereotypic actions using functional brain imaging. We developed a paradigm in which we compared four simple finger lifting movements that differed in plausibility and intentionality as varied by action context. We found three regions that seem to be involved in goal inference processing of non-stereotypic implausible actions: (1) The superior temporal sulcus, (2) the right inferior parietal cortex, at the junction with the posterior temporal cortex (TPJ), and (3) the angular gyrus of the inferior parietal lobule. In line with teleological reasoning accounts of action understanding, inferring others' goals from non-stereotypic actions seems to be the outcome of context-sensitive inferential processing. In agreement with previous findings, we found the mirror system to be more strongly activated for intentionally produced actions [Iacoboni, M., Molnar-Szakacs, I., Gallese, V., Buccino, G., Mazziotta, J.C., Rizzolatti, G., 2005. Grasping the intentions of others with one's own mirror neuron system. PLoS Biol. 3, e79.], indicating an involvement of the IFG in representing intentional actions. Our findings support the idea that goal inference processing for non-stereotypic actions is primarily mediated by reasoning about action and context rather than by a direct mapping process via the mirror system.

  15. Why I tense up when you watch me: Inferior parietal cortex mediates an audience’s influence on motor performance

    PubMed Central

    Yoshie, Michiko; Nagai, Yoko; Critchley, Hugo D.; Harrison, Neil A.

    2016-01-01

    The presence of an evaluative audience can alter skilled motor performance through changes in force output. To investigate how this is mediated within the brain, we emulated real-time social monitoring of participants’ performance of a fine grip task during functional magnetic resonance neuroimaging. We observed an increase in force output during social evaluation that was accompanied by focal reductions in activity within bilateral inferior parietal cortex. Moreover, deactivation of the left inferior parietal cortex predicted both inter- and intra-individual differences in socially-induced change in grip force. Social evaluation also enhanced activation within the posterior superior temporal sulcus, which conveys visual information about others’ actions to the inferior parietal cortex. Interestingly, functional connectivity between these two regions was attenuated by social evaluation. Our data suggest that social evaluation can vary force output through the altered engagement of inferior parietal cortex; a region implicated in sensorimotor integration necessary for object manipulation, and a component of the action-observation network which integrates and facilitates performance of observed actions. Social-evaluative situations may induce high-level representational incoherence between one’s own intentioned action and the perceived intention of others which, by uncoupling the dynamics of sensorimotor facilitation, could ultimately perturbe motor output. PMID:26787326

  16. The functional role of the inferior parietal lobe in the dorsal and ventral stream dichotomy

    PubMed Central

    Singh-Curry, Victoria; Husain, Masud

    2009-01-01

    Current models of the visual pathways have difficulty incorporating the human inferior parietal lobe (IPL) into dorsal or ventral streams. Some recent proposals have attempted to integrate aspects of IPL function that were not hitherto dealt with well, such as differences between the left and right hemisphere and the role of the right IPL in responding to salient environmental events. However, we argue that these models also fail to capture adequately some important findings regarding the functions of the IPL. Here we critically appraise existing proposals regarding the functional architecture of the visual system, with special emphasis on the role of this region, particularly in the right hemisphere. We review evidence that shows the right IPL plays an important role in two different, but broadly complementary, aspects of attention: maintaining attentive control on current task goals as well as responding to salient new information or alerting stimuli in the environment. In our view, findings from functional imaging, electrophysiological and lesion studies are all consistent with the view that this region is part of a system that allows flexible reconfiguration of behaviour between these two alternative modes of operation. Damage to the right IPL leads to deficits in both maintaining attention and also responding to salient events, impairments that contribute to hemineglect, the classical syndrome that follows lesions of this region. PMID:19138694

  17. Left inferior-parietal lobe activity in perspective tasks: identity statements.

    PubMed

    Arora, Aditi; Weiss, Benjamin; Schurz, Matthias; Aichhorn, Markus; Wieshofer, Rebecca C; Perner, Josef

    2015-01-01

    We investigate the theory that the left inferior parietal lobe (IPL) is closely associated with tracking potential differences of perspective. Developmental studies find that perspective tasks are mastered at around 4 years of age. Our first study, meta-analyses of brain imaging studies shows that perspective tasks specifically activate a region in the left IPL and precuneus. These tasks include processing of false belief, visual perspective, and episodic memory. We test the location specificity theory in our second study with an unusual and novel kind of perspective task: identity statements. According to Frege's classical logical analysis, identity statements require appreciation of modes of presentation (perspectives). We show that identity statements, e.g., "the tour guide is also the driver" activate the left IPL in contrast to a control statements, "the tour guide has an apprentice." This activation overlaps with the activations found in the meta-analysis. This finding is confirmed in a third study with different types of statements and different comparisons. All studies support the theory that the left IPL has as one of its overarching functions the tracking of perspective differences. We discuss how this function relates to the bottom-up attention function proposed for the bilateral IPL.

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

    PubMed

    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.

  19. The Role of Right Inferior Parietal Cortex in Auditory Spatial Attention: A Repetitive Transcranial Magnetic Stimulation Study

    PubMed Central

    Karhson, Debra S.; Mock, Jeffrey R.; Golob, Edward J.

    2015-01-01

    Behavioral studies support the concept of an auditory spatial attention gradient by demonstrating that attentional benefits progressively diminish as distance increases from an attended location. Damage to the right inferior parietal cortex can induce a rightward attention bias, which implicates this region in the construction of attention gradients. This study used event-related potentials (ERPs) to define attention-related gradients before and after repetitive transcranial magnetic stimulation (rTMS) to the right inferior parietal cortex. Subjects (n = 16) listened to noise bursts at five azimuth locations (left to right: -90°, -45°, 0° midline, +45°, +90°) and responded to stimuli at one target location (-90°, +90°, separate blocks). ERPs as a function of non-target location were examined before (baseline) and after 0.9 Hz rTMS. Results showed that ERP attention gradients were observed in three time windows (frontal 230–340, parietal 400–460, frontal 550–750 ms). Significant transient rTMS effects were seen in the first and third windows. The first window had a voltage decrease at the farthest location when attending to either the left or right side. The third window had on overall increase in positivity, but only when attending to the left side. These findings suggest that rTMS induced a small contraction in spatial attention gradients within the first time window. The asymmetric effect of attended location on gradients in the third time window may relate to neglect of the left hemispace after right parietal injury. Together, these results highlight the role of the right inferior parietal cortex in modulating frontal lobe attention network activity. PMID:26636333

  20. The left occipitotemporal system in reading: disruption of focal fMRI connectivity to left inferior frontal and inferior parietal language areas in children with dyslexia.

    PubMed

    van der Mark, Sanne; Klaver, Peter; Bucher, Kerstin; Maurer, Urs; Schulz, Enrico; Brem, Silvia; Martin, Ernst; Brandeis, Daniel

    2011-02-01

    Developmental dyslexia is a severe reading disorder, which is characterized by dysfluent reading and impaired automaticity of visual word processing. Adults with dyslexia show functional deficits in several brain regions including the so-called "Visual Word Form Area" (VWFA), which is implicated in visual word processing and located within the larger left occipitotemporal VWF-System. The present study examines functional connections of the left occipitotemporal VWF-System with other major language areas in children with dyslexia. Functional connectivity MRI was used to assess connectivity of the VWF-System in 18 children with dyslexia and 24 age-matched controls (age 9.7-12.5 years) using five neighboring left occipitotemporal regions of interest (ROIs) during a continuous reading task requiring phonological and orthographic processing. First, the results revealed a focal origin of connectivity from the VWF-System, in that mainly the VWFA was functionally connected with typical left frontal and parietal language areas in control children. Adjacent posterior and anterior VWF-System ROIs did not show such connectivity, confirming the special role that the VWFA plays in word processing. Second, we detected a significant disruption of functional connectivity between the VWFA and left inferior frontal and left inferior parietal language areas in the children with dyslexia. The current findings add to our understanding of dyslexia by showing that functional disconnection of the left occipitotemporal system is limited to the small VWFA region crucial for automatic visual word processing, and emerges early during reading acquisition in children with dyslexia, along with deficits in orthographic and phonological processing of visual word forms.

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

    PubMed

    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.

  2. Inferior-frontal cortex phase synchronizes with the temporal-parietal junction prior to successful change detection.

    PubMed

    Micheli, Cristiano; Kaping, Daniel; Westendorff, Stephanie; Valiante, Taufik A; Womelsdorf, Thilo

    2015-10-01

    The inferior frontal gyrus (IFG) and the temporo-parietal junction (TPJ) are believed to be core structures of human brain networks that activate when sensory top-down expectancies guide goal directed behavior and attentive perception. But it is unclear how activity in IFG and TPJ coordinates during attention demanding tasks and whether functional interactions between both structures are related to successful attentional performance. Here, we tested these questions in electrocorticographic (ECoG) recordings in human subjects using a visual detection task that required sustained attentional expectancy in order to detect non-salient, near-threshold visual events. We found that during sustained attention the successful visual detection was predicted by increased phase synchronization of band-limited 15-30 Hz beta band activity that was absent prior to misses. Increased beta-band phase alignment during attentional engagement early during the task was restricted to inferior and lateral prefrontal cortex, but with sustained attention it extended to long-range IFG-TPJ phase synchronization and included superior prefrontal areas. In addition to beta, a widely distributed network of brain areas comprising the occipital cortex showed enhanced and reduced alpha band phase synchronization before correct detections. These findings identify long-range phase synchrony in the 15-30 Hz beta band as the mesoscale brain signal that predicts the successful deployment of attentional expectancy of sensory events. We speculate that localized beta coherent states in prefrontal cortex index 'top-down' sensory expectancy whose coupling with TPJ subregions facilitates the gating of relevant visual information.

  3. Activity in inferior parietal and medial prefrontal cortex signals the accumulation of evidence in a probability learning task.

    PubMed

    d'Acremont, Mathieu; Fornari, Eleonora; Bossaerts, Peter

    2013-01-01

    In an uncertain environment, probabilities are key to predicting future events and making adaptive choices. However, little is known about how humans learn such probabilities and where and how they are encoded in the brain, especially when they concern more than two outcomes. During functional magnetic resonance imaging (fMRI), young adults learned the probabilities of uncertain stimuli through repetitive sampling. Stimuli represented payoffs and participants had to predict their occurrence to maximize their earnings. Choices indicated loss and risk aversion but unbiased estimation of probabilities. BOLD response in medial prefrontal cortex and angular gyri increased linearly with the probability of the currently observed stimulus, untainted by its value. Connectivity analyses during rest and task revealed that these regions belonged to the default mode network. The activation of past outcomes in memory is evoked as a possible mechanism to explain the engagement of the default mode network in probability learning. A BOLD response relating to value was detected only at decision time, mainly in striatum. It is concluded that activity in inferior parietal and medial prefrontal cortex reflects the amount of evidence accumulated in favor of competing and uncertain outcomes.

  4. Sense of agency is related to gamma band coupling in an inferior parietal-preSMA circuitry.

    PubMed

    Ritterband-Rosenbaum, Anina; Nielsen, Jens B; Christensen, Mark S

    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 task (Nielsen, 1963; Fourneret and Jeannerod, 1998), in which they moved a cursor on a digital tablet with their right hand without seeing the hand. Visual feedback displayed on a computer monitor was either in correspondence with or deviated from the actual movement. This made participants uncertain 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 connection to SMA in the late task phase, and a model with input to preSMA and modulation of the backward connection was favored for the early task phase. The analysis shows that IPC source activity in the 50-60 Hz range modulated preSMA source activity in the 40-70 Hz range in the presence of SoA compared with no SoA in the late task phase, but the test of the early task phase did not reveal any differences between presence and absence of SoA. We show that SoA is associated with a directionally specific between frequencies coupling from IPC to preSMA in the higher gamma (ɣ) band in the late task phase. This suggests that SoA is a retrospective perception, which is highly dependent on interpretation of the outcome of the performed action.

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

    PubMed

    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.

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

    PubMed Central

    Shinoura, Nobusada; Midorikawa, Akira; Onodera, Toshiyuki; Yamada, Ryozi; Tabei, Yusuke; Onda, Yasumitsu; Itoi, Chihiro; Saito, Seiko; Yagi, Kazuo

    2012-01-01

    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. PMID:22713399

  7. Spatial orientation and the representation of space with parietal lobe lesions.

    PubMed Central

    Karnath, H O

    1997-01-01

    Damage to the human parietal cortex leads to disturbances of spatial perception and of motor behaviour. Within the parietal lobe, lesions of the superior and of the inferior lobule induce quite different, characteristic deficits. Patients with inferior (predominantly right) parietal lobe lesions fail to explore the contralesional part of space by eye or limb movements (spatial neglect). In contrast, superior parietal lobe lesions lead to specific impairments of goal-directed movements (optic ataxia). The observations reported in this paper support the view of dissociated functions represented in the inferior and the superior lobule of the human parietal cortex. They suggest that a spatial reference frame for exploratory behaviour is disturbed in patients with neglect. Data from these patients' visual search argue that their failure to explore the contralesional side is due to a disturbed input transformation leading to a deviation of egocentric space representation to the ipsilesional side. Data further show that this deviation follows a rotation around the earth-vertical body axis to the ipsilesional side rather than a translation towards that side. The results are in clear contrast to explanations that assume a lateral gradient ranging from a minimum of exploration in the extreme contralesional to a maximum in the extreme ipsilesional hemispace. Moreover, the failure to orient towards and to explore the contralesional part of space appears to be distinct from those deficits observed once an object of interest has been located and releases reaching. Although patients with neglect exhibit a severe bias of exploratory movements, their hand trajectories to targets in peripersonal space may follow a straight path. This result suggests that (i) exploratory and (ii) goal-directed behaviour in space do not share the same neural control mechanisms. Neural representation of space in the inferior parietal lobule seems to serve as a matrix for spatial exploration and for

  8. [Parietal Cortices and Body Information].

    PubMed

    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.

  9. Interactions between visual attention and episodic retrieval: dissociable contributions of parietal regions during gist-based false recognition.

    PubMed

    Guerin, Scott A; Robbins, Clifford A; Gilmore, Adrian W; Schacter, Daniel L

    2012-09-20

    The interaction between episodic retrieval and visual attention is relatively unexplored. Given that systems mediating attention and episodic memory appear to be segregated, and perhaps even in competition, it is unclear how visual attention is recruited during episodic retrieval. We investigated the recruitment of visual attention during the suppression of gist-based false recognition, the tendency to falsely recognize items that are similar to previously encountered items. Recruitment of visual attention was associated with activity in the dorsal attention network. The inferior parietal lobule, often implicated in episodic retrieval, tracked veridical retrieval of perceptual detail and showed reduced activity during the engagement of visual attention, consistent with a competitive relationship with the dorsal attention network. These findings suggest that the contribution of the parietal cortex to interactions between visual attention and episodic retrieval entails distinct systems that contribute to different components of the task while also suppressing each other.

  10. Space and the parietal cortex

    PubMed Central

    Husain, Masud; Nachev, Parashkev

    2007-01-01

    Current views of the parietal cortex have difficulty accommodating the human inferior parietal lobe (IPL) within a simple dorsal versus ventral stream dichotomy. In humans, lesions of the right IPL often lead to syndromes such as hemispatial neglect that are seemingly in accord with the proposal that this region has a crucial role in spatial processing. However, recent imaging and lesion studies have revealed that inferior parietal regions have non-spatial functions, such as in sustaining attention, detecting salient events embedded in a sequence of events and controlling attention over time. Here, we review these findings and show that spatial processes and the visual guidance of action are only part of the repertoire of parietal functions. Although sub-regions in the human superior parietal lobe and intraparietal sulcus contribute to vision-for-action and spatial functions, more inferior parietal regions have distinctly non-spatial attributes that are neither conventionally ‘dorsal’ nor conventionally ‘ventral’ in nature. PMID:17134935

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

    PubMed

    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.

  12. Fronto-parietal regulation of media violence exposure in adolescents: a multi-method study.

    PubMed

    Strenziok, Maren; Krueger, Frank; Deshpande, Gopikrishna; Lenroot, Rhoshel K; van der Meer, Elke; Grafman, Jordan

    2011-10-01

    Adolescents spend a significant part of their leisure time watching TV programs and movies that portray violence. It is unknown, however, how the extent of violent media use and the severity of aggression displayed affect adolescents' brain function. We investigated skin conductance responses, brain activation and functional brain connectivity to media violence in healthy adolescents. In an event-related functional magnetic resonance imaging experiment, subjects repeatedly viewed normed videos that displayed different degrees of aggressive behavior. We found a downward linear adaptation in skin conductance responses with increasing aggression and desensitization towards more aggressive videos. Our results further revealed adaptation in a fronto-parietal network including the left lateral orbitofrontal cortex (lOFC), right precuneus and bilateral inferior parietal lobules, again showing downward linear adaptations and desensitization towards more aggressive videos. Granger causality mapping analyses revealed attenuation in the left lOFC, indicating that activation during viewing aggressive media is driven by input from parietal regions that decreased over time, for more aggressive videos. We conclude that aggressive media activates an emotion-attention network that has the capability to blunt emotional responses through reduced attention with repeated viewing of aggressive media contents, which may restrict the linking of the consequences of aggression with an emotional response, and therefore potentially promotes aggressive attitudes and behavior.

  13. Fronto-parietal regulation of media violence exposure in adolescents: a multi-method study

    PubMed Central

    Strenziok, Maren; Krueger, Frank; Deshpande, Gopikrishna; Lenroot, Rhoshel K.; van der Meer, Elke

    2011-01-01

    Adolescents spend a significant part of their leisure time watching TV programs and movies that portray violence. It is unknown, however, how the extent of violent media use and the severity of aggression displayed affect adolescents’ brain function. We investigated skin conductance responses, brain activation and functional brain connectivity to media violence in healthy adolescents. In an event-related functional magnetic resonance imaging experiment, subjects repeatedly viewed normed videos that displayed different degrees of aggressive behavior. We found a downward linear adaptation in skin conductance responses with increasing aggression and desensitization towards more aggressive videos. Our results further revealed adaptation in a fronto-parietal network including the left lateral orbitofrontal cortex (lOFC), right precuneus and bilateral inferior parietal lobules, again showing downward linear adaptations and desensitization towards more aggressive videos. Granger causality mapping analyses revealed attenuation in the left lOFC, indicating that activation during viewing aggressive media is driven by input from parietal regions that decreased over time, for more aggressive videos. We conclude that aggressive media activates an emotion–attention network that has the capability to blunt emotional responses through reduced attention with repeated viewing of aggressive media contents, which may restrict the linking of the consequences of aggression with an emotional response, and therefore potentially promotes aggressive attitudes and behavior. PMID:20934985

  14. Scene-Selectivity and Retinotopy in Medial Parietal Cortex

    PubMed Central

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

    2016-01-01

    surface, the caudal inferior parietal lobule (cIPL). However, the differential connectivity in medial parietal cortex was found principally anterior of MPA. We suggest that there is posterior–anterior gradient within medial parietal cortex, with posterior regions in the POS showing retinotopically based scene-selectivity and more anterior regions showing connectivity that may be more reflective of abstract, navigationally pertinent and possibly mnemonic representations. PMID:27588001

  15. CERES: A new cerebellum lobule segmentation method.

    PubMed

    Romero, Jose E; Coupé, Pierrick; Giraud, Rémi; Ta, Vinh-Thong; Fonov, Vladimir; Park, Min Tae M; Chakravarty, M Mallar; Voineskos, Aristotle N; Manjón, Jose V

    2017-02-15

    The human cerebellum is involved in language, motor tasks and cognitive processes such as attention or emotional processing. Therefore, an automatic and accurate segmentation method is highly desirable to measure and understand the cerebellum role in normal and pathological brain development. In this work, we propose a patch-based multi-atlas segmentation tool called CERES (CEREbellum Segmentation) that is able to automatically parcellate the cerebellum lobules. The proposed method works with standard resolution magnetic resonance T1-weighted images and uses the Optimized PatchMatch algorithm to speed up the patch matching process. The proposed method was compared with related recent state-of-the-art methods showing competitive results in both accuracy (average DICE of 0.7729) and execution time (around 5 minutes).

  16. Early Left Parietal Activity Elicited by Direct Gaze: A High-Density EEG Study

    PubMed Central

    Burra, Nicolas; Kerzel, Dirk; George, Nathalie

    2016-01-01

    Gaze is one of the most important cues for human communication and social interaction. In particular, gaze contact is the most primary form of social contact and it is thought to capture attention. A very early-differentiated brain response to direct versus averted gaze has been hypothesized. Here, we used high-density electroencephalography to test this hypothesis. Topographical analysis allowed us to uncover a very early topographic modulation (40–80 ms) of event-related responses to faces with direct as compared to averted gaze. This modulation was obtained only in the condition where intact broadband faces–as opposed to high-pass or low-pas filtered faces–were presented. Source estimation indicated that this early modulation involved the posterior parietal region, encompassing the left precuneus and inferior parietal lobule. This supports the idea that it reflected an early orienting response to direct versus averted gaze. Accordingly, in a follow-up behavioural experiment, we found faster response times to the direct gaze than to the averted gaze broadband faces. In addition, classical evoked potential analysis showed that the N170 peak amplitude was larger for averted gaze than for direct gaze. Taken together, these results suggest that direct gaze may be detected at a very early processing stage, involving a parallel route to the ventral occipito-temporal route of face perceptual analysis. PMID:27880776

  17. Functional architecture of spatial attention in the parietal cortex of behaving monkey

    PubMed Central

    Raffi, Milena; Siegel, Ralph M.

    2007-01-01

    Functional architectures facilitate orderly transmittal of representations between cortices, allow for local interactions between neurons, and ensure a uniform distribution of feature representations with respect to larger scale topographies. We sought to correlate such topographies with internal cognitive states. A psychophysical task for which the monkey was required to detect a change in one of two identical peripheral expanding flow fields tested for spatial shifts of attention. The monkey was cued as to which flow would change with a small cue near the fixation points. Reaction time data indicates that the monkey's performance in the optic flow detection task depended on the cue's location. Using optical imaging of intrinsic signals, we show that a monkey's internally generated locus of attention is correlated with an 800-860 μm patchy topological architecture across the cortical surface of the inferior parietal lobule. The attentional patches vary in location, but are stable in spatial frequency. The patches are embedded in a larger scale and stable representation of eye position. Trial-by-trial analysis of the images indicates that the organizational scheme with simultaneous stable and variable sub-components occurs within a day's experiment as well as across days. This novel functional architecture is the first to be correlated with attentional mechanisms and could support a fine scale functional architecture underlying hemispatial neglect, an attentional deficit caused by parietal lesions. PMID:15917457

  18. Emotion unfolded by motion: a role for parietal lobe in decoding dynamic facial expressions.

    PubMed

    Sarkheil, Pegah; Goebel, Rainer; Schneider, Frank; Mathiak, Klaus

    2013-12-01

    Facial expressions convey important emotional and social information and are frequently applied in investigations of human affective processing. Dynamic faces may provide higher ecological validity to examine perceptual and cognitive processing of facial expressions. Higher order processing of emotional faces was addressed by varying the task and virtual face models systematically. Blood oxygenation level-dependent activation was assessed using functional magnetic resonance imaging in 20 healthy volunteers while viewing and evaluating either emotion or gender intensity of dynamic face stimuli. A general linear model analysis revealed that high valence activated a network of motion-responsive areas, indicating that visual motion areas support perceptual coding for the motion-based intensity of facial expressions. The comparison of emotion with gender discrimination task revealed increased activation of inferior parietal lobule, which highlights the involvement of parietal areas in processing of high level features of faces. Dynamic emotional stimuli may help to emphasize functions of the hypothesized 'extended' over the 'core' system for face processing.

  19. Multisensory maps in parietal cortex☆

    PubMed Central

    Sereno, Martin I; Huang, Ruey-Song

    2014-01-01

    Parietal cortex has long been known to be a site of sensorimotor integration. Recent findings in humans have shown that it is divided up into a number of small areas somewhat specialized for eye movements, reaching, and hand movements, but also face-related movements (avoidance, eating), lower body movements, and movements coordinating multiple body parts. The majority of these areas contain rough sensory (receptotopic) maps, including a substantial multisensory representation of the lower body and lower visual field immediately medial to face VIP. There is strong evidence for retinotopic remapping in LIP and face-centered remapping in VIP, and weaker evidence for hand-centered remapping. The larger size of the functionally distinct inferior parietal default mode network in humans compared to monkeys results in a superior and medial displacement of middle parietal areas (e.g., the saccade-related LIP's). Multisensory superior parietal areas located anterior to the angular gyrus such as AIP and VIP are less medially displaced relative to macaque monkeys, so that human LIP paradoxically ends up medial to human VIP. PMID:24492077

  20. Dissociable Memory- and Response-Related Activity in Parietal Cortex During Auditory Spatial Working Memory

    PubMed Central

    Alain, Claude; Shen, Dawei; Yu, He; Grady, Cheryl

    2010-01-01

    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 functional magnetic resonance imaging 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 the 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. PMID:21833258

  1. The Role of Human Parietal Area 7A as a Link between Sequencing in Hand Actions and in Overt Speech Production

    PubMed Central

    Heim, Stefan; Amunts, Katrin; Hensel, Tanja; Grande, Marion; Huber, Walter; Binkofski, Ferdinand; Eickhoff, Simon B.

    2012-01-01

    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 focused 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 has yet to be elucidated. Thus, the present study investigated whether motor sequencing of hand vs. speech 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 previously underspecified role of the SPL in the origins of speech, and may be discussed in the light of embodiment of speech and language in the motor system. PMID:23227016

  2. Inferior frontal gyrus links visual and motor cortices during a visuomotor precision grip force task.

    PubMed

    Papadelis, Christos; Arfeller, Carola; Erla, Silvia; Nollo, Giandomenico; Cattaneo, Luigi; Braun, Christoph

    2016-11-01

    Coordination between vision and action relies on a fronto-parietal network that receives visual and proprioceptive sensory input in order to compute motor control signals. Here, we investigated with magnetoencephalography (MEG) which cortical areas are functionally coupled on the basis of synchronization during visuomotor integration. MEG signals were recorded from twelve healthy adults while performing a unimanual visuomotor (VM) task and control conditions. The VM task required the integration of pinch motor commands with visual sensory feedback. By using a beamformer, we localized the neural activity in the frequency range of 1-30Hz during the VM compared to rest. Virtual sensors were estimated at the active locations. A multivariate autoregressive model was used to estimate the power and coherence of estimated activity at the virtual sensors. Event-related desynchronisation (ERD) during VM was observed in early visual areas, the rostral part of the left inferior frontal gyrus (IFG), the right IFG, the superior parietal lobules, and the left hand motor cortex (M1). Functional coupling in the alpha frequency band bridged the regional activities observed in motor and visual cortices (the start and the end points in the visuomotor loop) through the left or right IFG. Coherence between the left IFG and left M1 correlated inversely with the task performance. Our results indicate that an occipital-prefrontal-motor functional network facilitates the modulation of instructed motor responses to visual cues. This network may supplement the mechanism for guiding actions that is fully incorporated into the dorsal visual stream.

  3. Mathematical modeling of the circulation in the liver lobule.

    PubMed

    Bonfiglio, Andrea; Leungchavaphongse, Kritsada; Repetto, Rodolfo; Siggers, Jennifer H

    2010-11-01

    In this paper, we develop a mathematical model of blood circulation in the liver lobule. We aim to find the pressure and flux distributions within a liver lobule. We also investigate the effects of changes in pressure that occur following a resection of part of the liver, which often leads to high pressure in the portal vein. The liver can be divided into functional units called lobules. Each lobule has a hexagonal cross-section, and we assume that its longitudinal extent is large compared with its width. We consider an infinite lattice of identical lobules and study the two-dimensional flow in the hexagonal cross-sections. We model the sinusoidal space as a porous medium, with blood entering from the portal tracts (located at each of the vertices of the cross-section of the lobule) and exiting via the centrilobular vein (located in the center of the cross-section). We first develop and solve an idealized mathematical model, treating the porous medium as rigid and isotropic and blood as a Newtonian fluid. The pressure drop across the lobule and the flux of blood through the lobule are proportional to one another. In spite of its simplicity, the model gives insight into the real pressure and velocity distribution in the lobule. We then consider three modifications of the model that are designed to make it more realistic. In the first modification, we account for the fact that the sinusoids tend to be preferentially aligned in the direction of the centrilobular vein by considering an anisotropic porous medium. In the second, we account more accurately for the true behavior of the blood by using a shear-thinning model. We show that both these modifications have a small quantitative effect on the behavior but no qualitative effect. The motivation for the final modification is to understand what happens either after a partial resection of the liver or after an implantation of a liver of small size. In these cases, the pressure is observed to rise significantly, which

  4. Spatial relations and spatial locations are dissociated within prefrontal and parietal cortex

    PubMed Central

    Ackerman, Christopher M.

    2012-01-01

    Item-specific spatial information is essential for interacting with objects and for binding multiple features of an object together. Spatial relational information is necessary for implicit tasks such as recognizing objects or scenes from different views but also for explicit reasoning about space such as planning a route with a map and for other distinctively human traits such as tool construction. To better understand how the brain supports these two different kinds of information, we used functional MRI to directly contrast the neural encoding and maintenance of spatial relations with that for item locations in equivalent visual scenes. We found a double dissociation between the two: whereas item-specific processing implicates a frontoparietal attention network, including the superior frontal sulcus and intraparietal sulcus, relational processing preferentially recruits a cognitive control network, particularly lateral prefrontal cortex (PFC) and inferior parietal lobule. Moreover, pattern classification revealed that the actual meaning of the relation can be decoded within these same regions, most clearly in rostrolateral PFC, supporting a hierarchical, representational account of prefrontal organization. PMID:22896722

  5. Morphology and digitally aided morphometry of the human paracentral lobule.

    PubMed

    Spasojević, Goran; Malobabic, Slobodan; Pilipović-Spasojević, Olivera; Djukić-Macut, Nataša; Maliković, Aleksandar

    2013-02-01

    The human paracentral lobule, the junction of the precentral and postcentral gyri at the medial hemispheric surface, contains several important functional regions, and its variable morphology requires exact morphological and quantitativedata. In order to obtain precise data we investigated the morphology of the paracentral lobule and quantified its visible (extrasulcal) surface. This surface corresponds to commonly used magnetic resonance imaging scout images. We studied 84 hemispheres of adult persons (42 brains; 26 males and 16 females; 20-65 years) fixed in neutral formalin for at least 4 weeks. The medial hemispheric surface was photographed at standard distance and each digital photo was calibrated. Using the intercommissural line system (commissura anterior-commissura posterior or CA-CP line), we performed standardised measurements of the paracentral lobule. Exact determination of its boundaries and morphological types was followed by digital morphometry of its extrasulcal surface using AutoCAD software. We found two distinct morphological types of the human paracentral lobule: continuous type, which was predominant (95.2%), and rare segmented type (4.8%). In hemispheres with segmented cingulate sulcus we also found the short transitional lobulo-limbic gyrus (13.1%). The mean extrasulcal surface of the left paracentral lobule was significantly larger, both in males (left 6.79 cm2 vs. right 5.76 cm2) and in females (left 6.05 cm2 vs. right 5.16 cm2). However, even larger average surfaces in males were not significantly different than the same in females. Reported morphological and quantitative data will be useful during diagnostics and treatment of pathologies affecting the human paracentral lobule, and in further studies of its cytoarchitectonic and functional parcellations.

  6. Mechanisms of spatial attention control in frontal and parietal cortex

    PubMed Central

    Szczepanski, Sara M.; Konen, Christina S.; Kastner, Sabine

    2010-01-01

    Theories of spatial attentional control have been largely based upon studies of patients suffering from visuo-spatial neglect, resulting from circumscribed lesions of frontal and posterior parietal cortex. In the intact brain, the control of spatial attention has been related to a distributed fronto-parietal attention network. Little is known about the nature of the control mechanisms exerted by this network. Here, we used a novel region-of-interest approach to relate activations of the attention network to recently described topographic areas in frontal (FEF, PreCC/IFS) and parietal cortex (IPS1-IPS5, SPL1) and to examine their spatial attention signals. We found that attention signals in most topographic areas were spatially-specific, with stronger responses when attention was directed to the contralateral than to the ipsilateral visual field. Importantly, two hemispheric asymmetries were found. First, a region in only right, but not left superior parietal lobule (SPL1) carried spatial attention signals. Second, left FEF and left posterior parietal cortex (IPS1/2) generated stronger contralateral biasing signals than their counterparts in the right hemisphere. These findings are the first to characterize spatial attention signals in topographic frontal and parietal cortex and provide a neural basis in support of an interhemispheric competition account of spatial attentional control. PMID:20053897

  7. Mathematically gifted adolescents use more extensive and more bilateral areas of the fronto-parietal network than controls during executive functioning and fluid reasoning tasks.

    PubMed

    Desco, Manuel; Navas-Sanchez, Francisco J; Sanchez-González, Javier; Reig, Santiago; Robles, Olalla; Franco, Carolina; Guzmán-De-Villoria, Juan A; García-Barreno, Pedro; Arango, Celso

    2011-07-01

    The main goal of this study was to investigate the neural substrates of fluid reasoning and visuospatial working memory in adolescents with precocious mathematical ability. The study population comprised two groups of adolescents: 13 math-gifted adolescents and 14 controls with average mathematical skills. Patterns of activation specific to reasoning tasks in math-gifted subjects were examined using functional magnetic resonance images acquired while the subjects were performing Raven's Advanced Progressive Matrices (RAPM) and the Tower of London (TOL) tasks. During the tasks, both groups showed significant activations in the frontoparietal network. In the math-gifted group, clusters of activation were always bilateral and more regions were recruited, especially in the right hemisphere. In the TOL task, math-gifted adolescents showed significant hyper-activations relative to controls in the precuneus, superior occipital lobe (BA 19), and medial temporal lobe (BA 39). The maximum differences between the groups were detected during RAPM tasks at the highest level of difficulty, where math-gifted subjects showed significant activations relative to controls in the right inferior parietal lobule (BA 40), anterior cingulated gyrus (BA 32), and frontal (BA 9, and BA 6) areas. Our results support the hypothesis that greater ability for complex mathematical reasoning may be related to more bilateral patterns of activation and that increased activation in the parietal and frontal regions of math-gifted adolescents is associated with enhanced skills in visuospatial processing and logical reasoning.

  8. Representation of numerosity in posterior parietal cortex

    PubMed Central

    Roitman, Jamie D.; Brannon, Elizabeth M.; Platt, Michael L.

    2012-01-01

    Humans and animals appear to share a similar representation of number as an analog magnitude on an internal, subjective scale. Neurological and neurophysiological data suggest that posterior parietal cortex (PPC) is a critical component of the circuits that form the basis of numerical abilities in humans. Patients with parietal lesions are impaired in their ability to access the deep meaning of numbers. Acalculiac patients with inferior parietal damage often have difficulty performing arithmetic (2 + 4?) or number bisection (what is between 3 and 5?) tasks, but are able to recite multiplication tables and read or write numerals. Functional imaging studies of neurologically intact humans performing subtraction, number comparison, and non-verbal magnitude comparison tasks show activity in areas within the intraparietal sulcus (IPS). Taken together, clinical cases and imaging studies support a critical role for parietal cortex in the mental manipulation of numerical quantities. Further, responses of single PPC neurons in non-human primates are sensitive to the numerosity of visual stimuli independent of low-level stimulus qualities. When monkeys are trained to make explicit judgments about the numerical value of such stimuli, PPC neurons encode their cardinal numerical value; without such training PPC neurons appear to encode numerical magnitude in an analog fashion. Here we suggest that the spatial and integrative properties of PPC neurons contribute to their critical role in numerical cognition. PMID:22666194

  9. Pure agnosia for mirror stimuli after right inferior parietal lesion.

    PubMed

    Priftis, Konstantinos; Rusconi, Elena; Umiltà, Carlo; Zorzi, Marco

    2003-04-01

    This study reports the experimental investigation of G.R., a patient suffering from a highly specific disorder in discriminating mirror stimuli following a right temporoparietal cerebrovascular accident. G.R. showed intact perceptual, attentional, mnestic, linguistic and executive abilities. Object recognition was accurate even under unusual viewing conditions. He was highly accurate in defining the canonical orientation of common objects and in discriminating misoriented objects among identical distracters. However, he was severely impaired in tasks requiring mirror-stimulus discrimination, a deficit that persisted even when the object's coordinates were systematically misaligned with respect to his body. The disorder was also dependent upon the frame of reference (allocentric versus egocentric) activated on the basis of task demands. These results demonstrate the existence of a highly specific disorder in discriminating mirror stimuli defined in object-based coordinates, suggesting a failure in processing the directionality of an object's intrinsic x-axis.

  10. The role of parietal cortex during sustained visual spatial attention.

    PubMed

    Thakral, Preston P; Slotnick, Scott D

    2009-12-11

    The control of spatial attention-shifting attention between visual field locations or sustaining attention to one location-involves the prefrontal cortex and parietal cortex. Within the parietal cortex, shifting attention has been linked to the superior parietal lobule; however, the neural substrates associated with sustained attention are still unknown. In the present fMRI study, we aimed to identify generalized control regions associated with sustained attention using two different protocols. The motion protocol alternated between periods of moving or stationary dots, and the flicker protocol alternated between periods of flickering or stationary checkerboards (each period lasted 14 s). During moving and flickering periods, the behavioral task alternated between sustained attention and perception. A region-of-interest analysis confirmed that the motion but not flicker protocol produced attention effects-greater activity associated with sustained attention than perception-in motion processing region MT+. A whole brain conjunction analysis identified regions commonly associated with sustained attention for both protocols, which included the right intraparietal sulcus (BA 7/40), the right middle frontal gyrus (BA 9/46), the right superior temporal gyrus (BA 22), the right insula (BA 13), and the left cerebellum. Coupled with previous results, the present findings suggest a functional-anatomic organization of parietal cortex where shifts in attention are mediated by superior regions and sustained attention is mediated by more lateral regions.

  11. Superior Parietal Lobule Dysfunction in a Homogeneous Group of Dyslexic Children with a Visual Attention Span Disorder

    ERIC Educational Resources Information Center

    Peyrin, C.; Demonet, J. F.; N'Guyen-Morel, M. A.; Le Bas, J. F.; Valdois, S.

    2011-01-01

    A visual attention (VA) span disorder has been reported in dyslexic children as potentially responsible for their poor reading outcome. The purpose of the current paper was to identify the cerebral correlates of this VA span disorder. For this purpose, 12 French dyslexic children with severe reading and VA span disorders and 12 age-matched control…

  12. Parietal cortex and representation of the mental Self

    PubMed Central

    Lou, Hans C.; Luber, Bruce; Crupain, Michael; Keenan, Julian P.; Nowak, Markus; Kjaer, Troels W.; Sackeim, Harold A.; Lisanby, Sarah H.

    2004-01-01

    For a coherent and meaningful life, conscious self-representation is mandatory. Such explicit “autonoetic consciousness” is thought to emerge by retrieval of memory of personally experienced events (“episodic memory”). During episodic retrieval, functional imaging studies consistently show 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-representation, we used transcranial magnetic stimulation over the region to transiently disturb neuronal circuitry. There was a decrease in the efficiency of retrieval of previous judgment of mental Self compared with retrieval of judgment of Other with transcranial magnetic stimulation at a latency of 160 ms, confirming the hypothesis. This network is strikingly similar to the network of the resting conscious state, suggesting that self-monitoring is a core function in resting consciousness. PMID:15096584

  13. Decoding Movement Goals from the Fronto-Parietal Reach Network

    PubMed Central

    Gertz, Hanna; Lingnau, Angelika; Fiehler, Katja

    2017-01-01

    During reach planning, fronto-parietal brain areas need to transform sensory information into a motor code. It is debated whether these areas maintain a sensory representation of the visual cue or a motor representation of the upcoming movement goal. Here, we present results from a delayed pro-/anti-reach task which allowed for dissociating the position of the visual cue from the reach goal. In this task, the visual cue was combined with a context rule (pro vs. anti) to infer the movement goal. Different levels of movement goal specification during the delay were obtained by presenting the context rule either before the delay together with the visual cue (specified movement goal) or after the delay (underspecified movement goal). By applying functional magnetic resonance imaging (fMRI) multivoxel pattern analysis (MVPA), we demonstrate movement goal encoding in the left dorsal premotor cortex (PMd) and bilateral superior parietal lobule (SPL) when the reach goal is specified. This suggests that fronto-parietal reach regions (PRRs) maintain a prospective motor code during reach planning. When the reach goal is underspecified, only area PMd but not SPL represents the visual cue position indicating an incomplete state of sensorimotor integration. Moreover, this result suggests a potential role of PMd in movement goal selection. PMID:28286476

  14. Apraxia and the Parietal Lobes

    ERIC Educational Resources Information Center

    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…

  15. Prolonged rock climbing activity induces structural changes in cerebellum and parietal lobe.

    PubMed

    Di Paola, Margherita; Caltagirone, Carlo; Petrosini, Laura

    2013-10-01

    This article analyzes whether climbing, a motor activity featured by upward movements by using both feet and hands, generation of new strategies of motor control, maintenance of not stable equilibrium and adoption of long-lasting quadrupedal posture, is able to modify specific brain areas. MRI data of 10 word-class mountain climbers (MC) and 10 age-matched controls, with no climbing experience were acquired. Combining region-of-interest analyses and voxel-based morphometry we investigated cerebellar volumes and correlation between cerebellum and whole cerebral gray matter. In comparison to controls, world-class MC showed significantly larger vermian lobules I-V volumes, with no significant difference in other cerebellar vermian lobules or hemispheres. The cerebellar enlargement was associated with an enlargement of right medial posterior parietal area. The specific features of the motor climbing skills perfectly fit with the plastic anatomical changes we found. The enlargement of the vermian lobules I-V seems to be related to highly dexterous hand movements and to eye-hand coordination in the detection of and correction of visuomotor errors. The concomitant enlargement of the parietal area is related to parallel work in predicting sensory consequences of action to make movement corrections. Motor control and sensory-motor prediction of actions make the difference between survive or not at extreme altitude.

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

    PubMed

    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.

  17. Role of the right inferior frontal gyrus in turn-based cooperation and competition: A near-infrared spectroscopy study.

    PubMed

    Liu, Tao; Saito, Hirofumi; Oi, Misato

    2015-10-01

    Interpersonal interaction can be classified into two types: concurrent and turn-based interaction, requiring synchronized body-movement and complementary behaviors across persons, respectively. To examine the neural mechanism of turn-based interaction, we simultaneously measured paired participants activations in their bilateral inferior frontal gyrus (IFG) and the bilateral inferior parietal lobule (IPL) in a turn-taking game using near-infrared spectroscopy (NIRS). Pairs of participants were assigned to either one of two roles (game builder and the partner) in the game. The builder's task was to make a copy of a target disk-pattern by placing disks on a monitor, while the partner's task was to aid the builder in his/her goal (cooperation condition) or to obstruct it (competition condition). The builder always took the initial move and the partner followed. The NIRS data demonstrated an interaction of role (builder vs. partner) by task-type (cooperation vs. competition) in the right IFG. The builder in the cooperation condition showed higher activation than the cooperator, but the same builder in the competition condition showed lower activation than in the cooperation condition. The activations in the competitor-builder pairs showed positive correlation between their right IFG, but the activations in the cooperator-builder pairs did not. These results suggest that the builder's activation in the right IFG is reduced/increased in the context of interacting with a cooperative/competitive partner. Also, the competitor may actively trace the builder's disk manipulation, leading to deeper mind-set synchronization in the competition condition, while the cooperator may passively follow the builder's move, leading to shallower mind-set synchronization in the cooperation condition.

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

    PubMed

    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.

  19. Models of breast morphogenesis based on localization of stem cells in the developing mammary lobule.

    PubMed

    Honeth, Gabriella; Schiavinotto, Tommaso; Vaggi, Federico; Marlow, Rebecca; Kanno, Tokuwa; Shinomiya, Ireneusz; Lombardi, Sara; Buchupalli, Bharath; Graham, Rosalind; Gazinska, Patrycja; Ramalingam, Vernie; Burchell, Joy; Purushotham, Anand D; Pinder, Sarah E; Csikasz-Nagy, Attila; Dontu, Gabriela

    2015-04-14

    Characterization of normal breast stem cells is important for understanding their role in breast development and in breast cancer. However, the identity of these cells is a subject of controversy and their localization in the breast epithelium is not known. In this study, we utilized a novel approach to analyze the morphogenesis of mammary lobules, by combining one-dimensional theoretical models and computer-generated 3D fractals. Comparing predictions of these models with immunohistochemical analysis of tissue sections for candidate stem cell markers, we defined distinct areas where stem cells reside in the mammary lobule. An increased representation of stem cells was found in smaller, less developed lobules compared to larger, more mature lobules, with marked differences in the gland of nulliparous versus parous women and that of BRCA1/2 mutation carriers versus non-carriers.

  20. Interhemispheric transfalcine approach and awake cortical mapping for resection of peri-atrial gliomas associated with the central lobule.

    PubMed

    Malekpour, Mahdi; Cohen-Gadol, Aaron A

    2015-02-01

    Medial posterior frontal and parietal gliomas extending to the peri-atrial region are difficult to reach surgically because of the working angle required to expose the lateral aspect of the tumor and the proximity of the tumor to the sensorimotor lobule; retraction of the sensorimotor cortex may lead to morbidity. The interhemispheric transfalcine approach is favorable and safe for resection of medial hemispheric tumors adjacent to the falx cerebri, but the literature on this approach is scarce. Awake cortical mapping using this operative route for tumors associated with the sensorimotor cortex has not been previously reported to our knowledge. We present the first case of a right medial posterior frontoparietal oligoastrocytoma that was resected through the interhemispheric transfalcine approach using awake cortical and subcortical mapping. Through a contralateral frontoparietal craniotomy, we excised a section of the falx and exposed the contralateral medial hemisphere. Cortical stimulation allowed localization of the supplementary motor cortex, and suprathreshold stimulation mapping excluded the primary motor cortex corresponding to the leg area. Gross total tumor resection was accomplished without any intraoperative or postoperative deficits. Awake cortical mapping using the contralateral transfalcine approach allows a "cross-court" operative route to map functional cortices and resect peri-atrial low-grade gliomas. This technique can minimize the otherwise necessary retraction on the ipsilateral hemisphere through an ipsilateral craniotomy.

  1. Fronto-parietal network supports context-dependent speech comprehension.

    PubMed

    Smirnov, Dmitry; Glerean, Enrico; Lahnakoski, Juha M; Salmi, Juha; Jääskeläinen, Iiro P; Sams, Mikko; Nummenmaa, Lauri

    2014-10-01

    Knowing the context of a discourse is an essential prerequisite for comprehension. Here we used functional magnetic resonance imaging (fMRI) to disclose brain networks supporting context-dependent speech comprehension. During fMRI, 20 participants listened to 1-min spoken narratives preceded by pictures that were either contextually matching or mismatching with the narrative. Matching pictures increased narrative comprehension, decreased hemodynamic activity in Broca׳s area, and enhanced its functional connectivity with left anterior superior frontal gyrus, bilateral inferior parietal cortex, as well as anterior and posterior cingulate cortex. Further, the anterior (BA 45) and posterior (BA 44) portions of Broca׳s area differed in their functional connectivity patterns. Both BA 44 and BA 45 have shown increased connectivity with right angular gyrus and supramarginal gyrus. Whereas BA 44 showed increased connectivity with left angular gyrus, left inferior/middle temporal gyrus and left postcentral gyrus, BA 45 showed increased connectivity with right posterior cingulate cortex, right anterior inferior frontal gyrus, lateral occipital cortex and anterior cingulate cortex. Our results suggest that a fronto-parietal functional network supports context-dependent narrative comprehension, and that Broca׳s area is involved in resolving ambiguity from speech when appropriate contextual cues are lacking.

  2. Fronto-parietal network supports context-dependent speech comprehension

    PubMed Central

    Smirnov, Dmitry; Glerean, Enrico; Lahnakoski, Juha M.; Salmi, Juha; Jääskeläinen, Iiro P.; Sams, Mikko; Nummenmaa, Lauri

    2014-01-01

    Knowing the context of a discourse is an essential prerequisite for comprehension. Here we used functional magnetic resonance imaging (fMRI) to disclose brain networks supporting context-dependent speech comprehension. During fMRI, 20 participants listened to 1-min spoken narratives preceded by pictures that were either contextually matching or mismatching with the narrative. Matching pictures increased narrative comprehension, decreased hemodynamic activity in Broca׳s area, and enhanced its functional connectivity with left anterior superior frontal gyrus, bilateral inferior parietal cortex, as well as anterior and posterior cingulate cortex. Further, the anterior (BA 45) and posterior (BA 44) portions of Broca׳s area differed in their functional connectivity patterns. Both BA 44 and BA 45 have shown increased connectivity with right angular gyrus and supramarginal gyrus. Whereas BA 44 showed increased connectivity with left angular gyrus, left inferior/middle temporal gyrus and left postcentral gyrus, BA 45 showed increased connectivity with right posterior cingulate cortex, right anterior inferior frontal gyrus, lateral occipital cortex and anterior cingulate cortex. Our results suggest that a fronto-parietal functional network supports context-dependent narrative comprehension, and that Broca׳s area is involved in resolving ambiguity from speech when appropriate contextual cues are lacking. PMID:25218167

  3. Liver-cell patterning lab chip: mimicking the morphology of liver lobule tissue.

    PubMed

    Ho, Chen-Ta; Lin, Ruei-Zeng; Chen, Rong-Jhe; Chin, Chung-Kuang; Gong, Song-En; Chang, Hwan-You; Peng, Hwei-Ling; Hsu, Long; Yew, Tri-Rung; Chang, Shau-Feng; Liu, Cheng-Hsien

    2013-09-21

    A lobule-mimetic cell-patterning technique for on-chip reconstruction of centimetre-scale liver tissue of heterogeneous hepatic and endothelial cells via an enhanced field-induced dielectrophoresis (DEP) trap is demonstrated and reported. By mimicking the basic morphology of liver tissue, the classic hepatic lobule, the lobule-mimetic-stellate-electrodes array was designed for cell patterning. Through DEP manipulation, well-defined and enhanced spatial electric field gradients were created for in-parallel manipulation of massive individual cells. With this liver-cell patterning labchip design, the original randomly distributed hepatic and endothelial cells inside the microfluidic chamber can be manipulated separately and aligned into the desired pattern that mimicks the morphology of liver lobule tissue. Experimental results showed that both hepatic and endothelial cells were orderly guided, snared, and aligned along the field-induced orientation to form the lobule-mimetic pattern. About 95% cell viability of hepatic and endothelial cells was also observed after cell-patterning demonstration via a fluorescent assay technique. The liver function of CYP450-1A1 enzyme activity showed an 80% enhancement for our engineered liver tissue (HepG2+HUVECs) compared to the non-patterned pure HepG2 for two-day culturing.

  4. Distinct cerebellar lobules process arousal, valence and their interaction in parallel following a temporal hierarchy.

    PubMed

    Styliadis, Charis; Ioannides, Andreas A; Bamidis, Panagiotis D; Papadelis, Christos

    2015-04-15

    The cerebellum participates in emotion-related neural circuits formed by different cortical and subcortical areas, which sub-serve arousal and valence. Recent neuroimaging studies have shown a functional specificity of cerebellar lobules in the processing of emotional stimuli. However, little is known about the temporal component of this process. The goal of the current study is to assess the spatiotemporal profile of neural responses within the cerebellum during the processing of arousal and valence. We hypothesized that the excitation and timing of distinct cerebellar lobules is influenced by the emotional content of the stimuli. By using magnetoencephalography, we recorded magnetic fields from twelve healthy human individuals while passively viewing affective pictures rated along arousal and valence. By using a beamformer, we localized gamma-band activity in the cerebellum across time and we related the foci of activity to the anatomical organization of the cerebellum. Successive cerebellar activations were observed within distinct lobules starting ~160ms after the stimuli onset. Arousal was processed within both vermal (VI and VIIIa) and hemispheric (left Crus II) lobules. Valence (left VI) and its interaction (left V and left Crus I) with arousal were processed only within hemispheric lobules. Arousal processing was identified first at early latencies (160ms) and was long-lived (until 980ms). In contrast, the processing of valence and its interaction to arousal was short lived at later stages (420-530ms and 570-640ms respectively). Our findings provide for the first time evidence that distinct cerebellar lobules process arousal, valence, and their interaction in a parallel yet temporally hierarchical manner determined by the emotional content of the stimuli.

  5. Parietal bone osteomyelitis in melioidosis

    PubMed Central

    Shetty, Hariprasad Sadanand; Mallela, Ajay Raj; Shastry, Barkur Ananthakrishna; Acharya, Vasudeva

    2015-01-01

    We report a case of a 55-year-old man with uncontrolled diabetes who presented with pneumonia. During his hospital stay his clinical status worsened and he had a focal seizure. MRI showed central nervous system involvement and parietal bone osteomyelitis. As the patient's blood culture and endotracheal aspirate grew Burkholderia pseudomallei, melioidosis was diagnosed. He was treated with meropenem after failure to respond to ceftazidime. He gradually improved over a period of 4 weeks and was discharged. Early diagnosis and therapy resulted in improved outcome. PMID:25725029

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

    PubMed

    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.

  7. The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex

    PubMed Central

    Jeong, Su Keun; Xu, Yaoda

    2016-01-01

    The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region. PMID:27494544

  8. Microstructure analysis of the secondary pulmonary lobules by 3D synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Fukuoka, Y.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Ohmatsu, H.; Moriyama, N.; Itoh, H.

    2014-03-01

    Recognition of abnormalities related to the lobular anatomy has become increasingly important in the diagnosis and differential diagnosis of lung abnormalities at clinical routines of CT examinations. This paper aims a 3-D microstructural analysis of the pulmonary acinus with isotropic spatial resolution in the range of several micrometers by using micro CT. Previously, we demonstrated the ability of synchrotron radiation micro CT (SRμCT) using offset scan mode in microstructural analysis of the whole part of the secondary pulmonary lobule. In this paper, we present a semiautomatic method to segment the acinar and subacinar airspaces from the secondary pulmonary lobule and to track small vessels running inside alveolar walls in human acinus imaged by the SRμCT. The method beains with and segmentation of the tissues such as pleural surface, interlobular septa, alveola wall, or vessel using a threshold technique and 3-D connected component analysis. 3-D air space are then conustructed separated by tissues and represented branching patterns of airways and airspaces distal to the terminal bronchiole. A graph-partitioning approach isolated acini whose stems are interactively defined as the terminal bronchiole in the secondary pulmonary lobule. Finally, we performed vessel tracking using a non-linear sate space which captures both smoothness of the trajectories and intensity coherence along vessel orientations. Results demonstrate that the proposed method can extract several acinar airspaces from the 3-D SRμCT image of secondary pulmonary lobule and that the extracted acinar airspace enable an accurate quantitative description of the anatomy of the human acinus for interpretation of the basic unit of pulmonary structure and function.

  9. Transaminase abnormalities and adaptations of the liver lobule manifest at specific cut-offs of steatosis

    PubMed Central

    Hall, Andrew; Covelli, Claudia; Manuguerra, Roberta; Luong, Tu Vinh; Buzzetti, Elena; Tsochatzis, Emmanuel; Pinzani, Massimo; Dhillon, Amar Paul

    2017-01-01

    There is little documented evidence suggesting that liver fat is responsible for liver injury in the absence of other disease processes. We investigated the relationships between liver fat, aminotransferases and hepatic architecture in liver biopsies with simple steatosis. We identified 136 biopsies with simple steatosis from the Royal Free Hospital Archives with both clinical data and sufficient material. Digital image analysis was employed to measure fat proportionate area (mFPA). Hepatocyte area (HA) and lobule radius (LR) were also measured. There were significant increases in ALT (p < 0.001) and AST (p = 0.013) with increased fat content and evidence to suggest both 5% and 20% mFPA as a cut-off for raised ALT. In liver with increased fat content there were significant increases in HA (p < 0.001). LR also increased as mFPA increased to 10% (p < 0.001), at which point the lobule ceased to expand further and was counterbalanced with a decrease in the number of hepatocytes per lobule (p = 0.029). Consequently there are mechanisms of adaption in the liver architecture to accommodate the accumulation of fat and these are accompanied by significant increases in transaminases. These results support the generally accepted cut-off of 5% fat for steatosis and indicate 20% as a threshold of more severe liver injury. PMID:28106158

  10. Spatio-temporal Model of Xenobiotic Distribution and Metabolism in an in Silico Mouse Liver Lobule

    NASA Astrophysics Data System (ADS)

    Fu, Xiao; Sluka, James; Clendenon, Sherry; Glazier, James; Ryan, Jennifer; Dunn, Kenneth; Wang, Zemin; Klaunig, James

    Our study aims to construct a structurally plausible in silico model of a mouse liver lobule to simulate the transport of xenobiotics and the production of their metabolites. We use a physiologically-based model to calculate blood-flow rates in a network of mouse liver sinusoids and simulate transport, uptake and biotransformation of xenobiotics within the in silico lobule. Using our base model, we then explore the effects of variations of compound-specific (diffusion, transport and metabolism) and compound-independent (temporal alteration of blood flow pattern) parameters, and examine their influence on the distribution of xenobiotics and metabolites. Our simulations show that the transport mechanism (diffusive and transporter-mediated) of xenobiotics and blood flow both impact the regional distribution of xenobiotics in a mouse hepatic lobule. Furthermore, differential expression of metabolic enzymes along each sinusoid's portal to central axis, together with differential cellular availability of xenobiotics, induce non-uniform production of metabolites. Thus, the heterogeneity of the biochemical and biophysical properties of xenobiotics, along with the complexity of blood flow, result in different exposures to xenobiotics for hepatocytes at different lobular locations. We acknowledge support from National Institute of Health GM 077138 and GM 111243.

  11. Characterization of lobulated fibers in limb girdle muscular dystrophy type 2A by gene expression profiling.

    PubMed

    Keira, Yoko; Noguchi, Satoru; Kurokawa, Rumi; Fujita, Masako; Minami, Narihiro; Hayashi, Yukiko K; Kato, Takashi; Nishino, Ichizo

    2007-04-01

    Limb girdle muscular dystrophy type 2A (LGMD2A) is caused by mutations in CAPN3, which encodes an intracellular cysteine protease. To elucidate the fundamental molecular changes that may be responsible for the pathological features of LGMD2A, we employed cDNA microarray analysis. We divided LGMD2A muscles into two groups according to specific pathological features: an early-stage group characterized by the presence of active necrosis and a regeneration process and a later-stage group characterized by the presence of lobulated fibers. After comparing the gene expression profiles of the two groups of LGMD2A muscles with control muscles, we identified 29 genes whose mRNA expression profiles were specifically altered in muscles with lobulated fibers. Interestingly, this group included genes that encode actin filament binding and regulatory proteins, such as gelsolin, PDZ and LIM domain 3 (PDLIM3) and troponin I1. Western blot analysis confirmed the upregulation of these proteins. From these results, we propose that abnormal increased expression of actin filament binding proteins may contribute to the changes of the intra-myofiber structures, observed in lobulated fibers in LGMD2A.

  12. Inferior vestibular neuritis.

    PubMed

    Kim, Ji-Soo; Kim, Hyo Jung

    2012-08-01

    Vestibular neuritis (VN) mostly involves the superior portion of the vestibular nerve and labyrinth. This study aimed to describe the clinical features of VN involving the inferior vestibular labyrinth and its afferents only. Of the 703 patients with a diagnosis of VN or labyrinthitis at Seoul National University Bundang Hospital from 2004 to 2010, we retrospectively recruited 9 patients (6 women, age range 15-75) with a diagnosis of isolated inferior VN. Diagnosis of isolated inferior VN was based on torsional downbeating spontaneous nystagmus, abnormal head-impulse test (HIT) for the posterior semicircular canal (PC), and abnormal cervical vestibular-evoked myogenic potentials (VEMP) in the presence of normally functioning horizontal and anterior semicircular canals, as determined by normal HIT and bithermal caloric tests. All patients presented with acute vertigo with nausea, vomiting, and imbalance. Three patients also had tinnitus and hearing loss in the involved side. The rotation axis of torsional downbeating spontaneous nystagmus was best aligned with that of the involved PC. HIT was also positive only for the involved PC. Cervical VEMP was abnormal in seven patients, and ocular VEMP was normal in all four patients tested. Ocular torsion and subjective visual vertical tests were mostly within the normal range. Since isolated inferior VN lacks the typical findings of much more prevalent superior VN, it may be mistaken for a central vestibular disorder. Recognition of this rare disorder may help avoid unnecessary workups in patients with acute vestibulopathy.

  13. Seeing is not feeling: posterior parietal but not somatosensory cortex engagement during touch observation.

    PubMed

    Chan, Annie W-Y; Baker, Chris I

    2015-01-28

    Observing touch has been reported to elicit activation in human primary and secondary somatosensory cortices and is suggested to underlie our ability to interpret other's behavior and potentially empathy. However, despite these reports, there are a large number of inconsistencies in terms of the precise topography of activation, the extent of hemispheric lateralization, and what aspects of the stimulus are necessary to drive responses. To address these issues, we investigated the localization and functional properties of regions responsive to observed touch in a large group of participants (n = 40). Surprisingly, even with a lenient contrast of hand brushing versus brushing alone, we did not find any selective activation for observed touch in the hand regions of somatosensory cortex but rather in superior and inferior portions of neighboring posterior parietal cortex, predominantly in the left hemisphere. These regions in the posterior parietal cortex required the presence of both brush and hand to elicit strong responses and showed some selectivity for the form of the object or agent of touch. Furthermore, the inferior parietal region showed nonspecific tactile and motor responses, suggesting some similarity to area PFG in the monkey. Collectively, our findings challenge the automatic engagement of somatosensory cortex when observing touch, suggest mislocalization in previous studies, and instead highlight the role of posterior parietal cortex.

  14. Parietal connectivity mediates multisensory facilitation.

    PubMed

    Brang, David; Taich, Zachary J; Hillyard, Steven A; Grabowecky, Marcia; Ramachandran, V S

    2013-09-01

    Our senses interact in daily life through multisensory integration, facilitating perceptual processes and behavioral responses. The neural mechanisms proposed to underlie this multisensory facilitation include anatomical connections directly linking early sensory areas, indirect connections to higher-order multisensory regions, as well as thalamic connections. Here we examine the relationship between white matter connectivity, as assessed with diffusion tensor imaging, and individual differences in multisensory facilitation and provide the first demonstration of a relationship between anatomical connectivity and multisensory processing in typically developed individuals. Using a whole-brain analysis and contrasting anatomical models of multisensory processing we found that increased connectivity between parietal regions and early sensory areas was associated with the facilitation of reaction times to multisensory (auditory-visual) stimuli. Furthermore, building on prior animal work suggesting the involvement of the superior colliculus in this process, using probabilistic tractography we determined that the strongest cortical projection area connected with the superior colliculus includes the region of connectivity implicated in our independent whole-brain analysis.

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

    PubMed Central

    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

  16. Multi-lobulation of the nucleus in prolonged S phase by nuclear expression of Chk tyrosine kinase

    SciTech Connect

    Nakayama, Yuji; Yamaguchi, Naoto . E-mail: nyama@p.chiba-u.ac.jp

    2005-04-01

    Chk tyrosine kinase phosphorylates Src-family tyrosine kinases and suppresses their kinase activity. We recently showed that Chk localizes to the nucleus as well as the cytoplasm and inhibits cell proliferation. To investigate the role of nuclear Chk in proliferation, various Chk mutants were constructed and expressed. Nuclear localization of Chk-induced dynamic multi-lobulation of the nucleus and prolonged S phase of the cell cycle. The N-terminal domain of Chk and a portion of its kinase domain but not the kinase activity were responsible for induction of the multi-lobulation. Cell sorting analysis revealed that nuclear multi-lobulated cells were enriched in late S phase. Multi-lobulated nuclei were surrounded with lamin B1 that was particularly concentrated in concave regions of the nuclei. Furthermore, treatment with nocodazole or taxol disrupted multi-lobulation of the nucleus. These results suggest that nuclear multi-lobulation in late S phase, which is dependent on polymerization and depolymerization of microtubules, may be involved in nuclear Chk-induced inhibition of proliferation.

  17. Perceptual Pseudoneglect in Schizophrenia: Candidate Endophenotype and the Role of the Right Parietal Cortex

    PubMed Central

    Ribolsi, Michele; Lisi, Giulia; Di Lorenzo, Giorgio; Koch, Giacomo; Oliveri, Massimiliano; Magni, Valentina; Pezzarossa, Bianca; Saya, Anna; Rociola, Giuseppe; Rubino, Ivo A.; Niolu, Cinzia; Siracusano, Alberto

    2013-01-01

    Several contributions have reported an altered expression of pseudoneglect in psychiatric disorders, highlighting the existence of an anomalous brain lateralization in affected subjects. Surprisingly, no studies have yet investigated pseudoneglect in first-degree relatives (FdR) of psychiatric patients. We investigated performance on “paper and pencil” line bisection (LB) tasks in 68 schizophrenic patients (SCZ), 42 unaffected FdR, 41 unipolar depressive patients (UP), and 103 healthy subjects (HS). A subgroup of 20 SCZ and 16 HS underwent computerized LB and mental number line bisection (MNL) tasks requiring judgment of prebisected lines and numerical intervals. Moreover, we evaluated, in a subgroup of 15 SCZ, performance on LB and MNL before and after parietal transcranial direct current stimulation (tDCS). In comparison to HS and UP, SCZ showed a systematic rightward bias on LB, partially corrected by selective right posterior parietal tDCS. Interestingly, even FdR showed a lack of pseudoneglect on LB, expressing a mean error lying in the middle between those of HS and SCZ. On the other hand, our results showed no significant difference between the performance of SCZ and HS on MNL. Both groups showed a comparable leftward bias that could not be significantly altered after left or right parietal tDCS. These findings confirm the existence of reduced lateralization in SCZ, suggesting specific impaired functioning of the right parietal lobule. Notably, we report a lack of pseudoneglect not only in SCZ but also in FdR, raising the hypothesis that an inverted laterality pattern may be considered a concrete marker of schizotypal traits. PMID:22419195

  18. Sclerosing lymphocytic lobulitis manifesting as suspicious microcalcifications with Hashimoto's thyroiditis in a young woman.

    PubMed

    Park, Sung Hee; Choi, Seung Joon; Jung, Hyun Kyung

    2013-01-01

    Sclerosing lymphocytic lobulitis (SLL) is a rare inflammatory disorder, which is also known as fibrous mastopathy and lymphocytic mastitis. It is commonly associated with autoimmune disorders, particularly type 1 diabetes and thyroiditis. We report the case of a 28-year-old woman diagnosed as SLL with Hashimoto's thyroiditis, but without diabetes. She presented suspicious microcalcifications without palpable mass in routine mammograms in both breasts. She had been diagnosed as Hashimoto's thyroiditis several years before and had been followed up in endo-clinics.

  19. Gelastic seizures involving the left parietal lobe.

    PubMed

    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.

  20. Anosognosia in parietal lobe syndrome.

    PubMed

    Ramachandran, V S

    1995-03-01

    Patients with right parietal lesions often deny their paralysis (anosognosia), but do they have "tacit" knowledge of their paralysis? I devised three novel tests to explore this. First, the patients were given a choice between a bimanual task (e.g., tying shoe laces) vs a unimanual one (e.g., threading a bolt). They chose the former on 17 of 18 trials and, surprisingly, showed no frustration or learning despite repeated failed attempts. I conclude that they have no tacit knowledge of paralysis (or, if such knowledge exists, it is not available for this particular task). Second, I used a "virtual reality box" to convey the optical illusion to the patient that she was moving her paralyzed left hand up and down to the rhythm of a metronome, and yet she showed no sign of surprise. Third, I irrigated patient BM's left ear canal with cold water, a procedure that is known to shift that patient's spatial frame of reference by stimulating the vestibular system. Surprisingly, this allowed her "repressed" memory of the paralysis to come to the surface; she said she had been paralyzed continuously for several days. I suggest that the vestibular stimulation produces these remarkable effects by mimicking REM sleep. These patients also employ a whole arsenal of grossly exaggerated Freudian "defense mechanisms" to account for their paralysis. To explain this, I propose that in normal individuals the left hemisphere ordinarily deals with small, local anomalies by trying to impose consistency but, when the anomaly exceeds threshold, an interaction with the right hemisphere forces a "paradigm shift." A failure of this process, in patients with right hemisphere damage, might partially account for anosognosia. Finally, I present a new conceptual framework that may help link several psychological and neurological phenomena such as Freudian defense mechanisms, vestibular stimulation, anosognosia, memory repression, visual illusions, anterograde amnesia, REM sleep, dreaming, and humor.

  1. Gelastic seizures involving the right parietal lobe.

    PubMed

    Shin, Hee-Young; Hong, Seung Bong; Joo, Eun Yeon; Tae, Woo Suk; Han, Sun Jung; Cho, Jae Wook; Seo, Dae Won; Kim, Sun Hyung; Lee, Jong-Min; Kim, Sun I

    2006-09-01

    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 an hypothalamic hamartoma. We report a patient with gelastic seizures involving the right parietal lobe. Our patient, a 32-year-old man, underwent video-EEG monitoring, interictal and ictal brain SPECTs during gelastic seizures. Subtraction ictal SPECT co-registered to MRI (SISCOM), was performed to localize any ictal hyperperfusion during these gelastic seizures. The seizures consisted of brief staring followed by smiling and laughing. Electroencephalography during the gelastic seizures showed rhythmic sharp waves in the right parietal lobe. SISCOM showed ictal hyperperfusion in the right parietal lobe and medial portions of right cerebellum. Our findings suggest that the right parietal lobe may actively participate in the particular epileptogenic network generating gelastic seizures.

  2. Genetics Home Reference: enlarged parietal foramina

    MedlinePlus

    ... parietal foramina is an inherited condition of impaired skull development. It is characterized by enlarged openings (foramina) ... that form the top and sides of the skull. This condition is due to incomplete bone formation ( ...

  3. Ultrasonography of histologically normal parathyroid glands and thyroid lobules in normocalcemic dogs.

    PubMed

    Liles, Sofija R; Linder, Keith E; Cain, Brandon; Pease, Anthony P

    2010-01-01

    The purpose of this study is to characterize the sonographic appearance of canine parathyroid glands using high-resolution ultrasonography. Ten cadaver dogs were studied after euthanasia for reasons not relating to the parathyroid. The cervical region was examined using a 13-5 MHz linear transducer in right and left recumbency. Ultrasonographic features of the parathyroid and thyroid glands were compared with the gross and histopathologic findings. Thirty-five structures were identified sonographically as parathyroid glands but only 26 of 35 glands (74% positive predictive value) were proven to be normal parathyroid glands histopathologically. Of the nine false positives, five (14%) were proven to be lobular thyroid tissue. The remaining four (11%) structures were visible grossly or found histopathologically. There were no statistical differences between ultrasonographic and gross measurements of the parathyroid glands. The average size as seen sonographically was 3.3 x 2.2 x 1.7 mm and the average gross size was 3.7 x 2.6 x 1.6 mm (length, width, height). The average size of the thyroid lobules assessed sonographically was 2.3 x1.6 x 0.8 mm (length, width, height). Normal parathyroid glands can be identified using high-resolution ultrasonography. But some thyroid lobules will be misinterpreted as parathyroid glands; this will result in false positives when identifying parathyroid glands with ultrasonography.

  4. Prostate Cancer Presenting with Parietal Bone Metastasis

    PubMed Central

    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.

  5. Dramatic Cataplexy Improvement Following Right Parietal Surgery

    PubMed Central

    Fam, David J.; Shammi, Prathiba; Mainprize, Todd G.; Murray, Brian J.

    2015-01-01

    This is the case of a 34-year-old woman with severe narcolepsy with cataplexy who experienced a dramatic reduction in cataplexy symptoms after resection of a right parietal astrocytoma. The patient underwent detailed neurological exam, neuropsychological testing, polysomnography and multiple sleep latency testing following surgery. Citation: Fam DJ, Shammi P, Mainprize TG, Murray BJ. Dramatic cataplexy improvement following right parietal surgery. J Clin Sleep Med 2015;11(7):829–830. PMID:25902819

  6. Isolated inferior mesenteric portal hypertension with giant inferior mesenteric vein and anomalous inferior mesenteric vein insertion

    PubMed Central

    Prasad, G. Raghavendra; Billa, Srikar; Bhandari, Pavaneel; Hussain, Aijaz

    2013-01-01

    Extrahepatic portal hypertension is not an uncommon disease in childhood, but isolated inferior mesenteric portal varices and lower gastrointestinal (GI) bleed have not been reported till date. A 4-year-old girl presented with lower GI bleed. Surgical exploration revealed extrahepatic portal vein obstruction with giant inferior mesenteric vein and colonic varices. Inferior mesenteric vein was joining the superior mesenteric vein. The child was treated successfully with inferior mesenteric – inferior vena caval anastomosis. The child was relieved of GI bleed during the follow-up. PMID:23798814

  7. Gastrin receptors on isolated canine parietal cells

    SciTech Connect

    Soll, A.H.; Amirian, D.A.; Thomas, L.P.; Reedy, T.J.; Elashoff, J.D.

    1984-05-01

    The receptors in the fundic mucosa that mediate gastrin stimulation of acid secretion have been studied. Synthetic human gastrin-17-I (G17) with a leucine substitution in the 15th position ((Leu15)-G17) was iodinated by chloramine T; high saturable binding was found to enzyme-dispersed canine fundic mucosal cells. /sup 127/I-(Leu15)-G17, but not /sup 127/I-G17, retained binding potency and biological activity comparable with uniodinated G17. Fundic mucosal cells were separated by size by using an elutriator rotor, and specific /sup 125/I-(Leu-15)-G17 binding in the larger cell fractions was highly correlated with the distribution of parietal cells. There was, however, specific gastrin binding in the small cell fractions, not accounted for by parietal cells. Using sequential elutriation and stepwise density gradients, highly enriched parietal and chief cell fractions were prepared; /sup 125/I-(Leu15)-G17 binding correlated positively with the parietal cell (r . 0.98) and negatively with chief cell content (r . -0.96). In fractions enriched to 45-65% parietal cells, specific /sup 125/I-(Leu15)-G17 binding was rapid, reaching a steady state at 37 degrees C within 30 min. Dissociation was also rapid, with the rate similar after 100-fold dilution or dilution plus excess pentagastrin. At a tracer concentration from 10 to 30 pM, saturable binding was 7.8 +/- 0.8% per 10(6) cells (mean +/- SE) and binding in the presence of excess pentagastrin accounted for 11% of total binding. G17 and carboxyl terminal octapeptide of cholecystokinin (26-33) were equipotent in displacing tracer binding and in stimulating parietal cell function ((/sup 14/C)aminopyrine accumulation), whereas the tetrapeptide of gastrin (14-17) had a much lower potency. Proglumide inhibited gastrin binding and selectively inhibited gastrin stimulation of parietal cell function.

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

    PubMed

    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.

  9. Functional versus effector-specific organization of the human posterior parietal cortex: revisited

    PubMed Central

    Leone, Frank T. M.; Medendorp, W. Pieter

    2016-01-01

    It has been proposed that the posterior parietal cortex (PPC) is characterized by an effector-specific organization. However, strikingly similar functional MRI (fMRI) activation patterns have been found in the PPC for hand and foot movements. Because the fMRI signal is related to average neuronal activity, similar activation levels may result either from effector-unspecific neurons or from intermingled subsets of effector-specific neurons within a voxel. We distinguished between these possibilities using fMRI repetition suppression (RS). Participants made delayed, goal-directed eye, hand, and foot movements to visual targets. In each trial, the instructed effector was identical or different to that of the previous trial. RS effects indicated an attenuation of the fMRI signal in repeat trials. The caudal PPC was active during the delay but did not show RS, suggesting that its planning activity was effector independent. Hand and foot-specific RS effects were evident in the anterior superior parietal lobule (SPL), extending to the premotor cortex, with limb overlap in the anterior SPL. Connectivity analysis suggested information flow between the caudal PPC to limb-specific anterior SPL regions and between the limb-unspecific anterior SPL toward limb-specific motor regions. These results underline that both function and effector specificity should be integrated into a concept of PPC action representation not only on a regional but also on a fine-grained, subvoxel level. PMID:27466132

  10. Functional heterogeneity in posterior parietal cortex across attention and episodic memory retrieval.

    PubMed

    Hutchinson, J Benjamin; Uncapher, Melina R; Weiner, Kevin S; Bressler, David W; Silver, Michael A; Preston, Alison R; Wagner, Anthony D

    2014-01-01

    While attention is critical for event memory, debate has arisen regarding the extent to which posterior parietal cortex (PPC) activation during episodic retrieval reflects engagement of PPC-mediated mechanisms of attention. Here, we directly examined the relationship between attention and memory, within and across subjects, using functional magnetic resonance imaging attention-mapping and episodic retrieval paradigms. During retrieval, 4 functionally dissociable PPC regions were identified. Specifically, 2 PPC regions positively tracked retrieval outcomes: lateral intraparietal sulcus (latIPS) indexed graded item memory strength, whereas angular gyrus (AnG) tracked recollection. By contrast, 2 other PPC regions demonstrated nonmonotonic relationships with retrieval: superior parietal lobule (SPL) tracked retrieval reaction time, consistent with a graded engagement of top-down attention, whereas temporoparietal junction displayed a complex pattern of below-baseline retrieval activity, perhaps reflecting disengagement of bottom-up attention. Analyses of retrieval effects in PPC topographic spatial attention maps (IPS0-IPS5; SPL1) revealed that IPS5 and SPL1 exhibited a nonmonotonic relationship with retrieval outcomes resembling that in the SPL region, further suggesting that SPL activation during retrieval reflects top-down attention. While demands on PPC attention mechanisms vary during retrieval attempts, the present functional parcellation of PPC indicates that 2 additional mechanisms (mediated by latIPS and AnG) positively track retrieval outcomes.

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

    PubMed

    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.

  12. Abnormal parietal encephalomalacia associated with schizophrenia

    PubMed Central

    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. Ultrastructure of spermatogonia and spermatocyte lobules in Taenia solium strobilae (Cestoda, Cyclophyllidea, Taeniidae) from golden hamsters.

    PubMed

    Willms, Kaethe; Caro, Jose Antonio; Robert, Lilia

    2003-08-01

    Golden hamsters ( Mesocricetus auratus) were infected with Taenia solium metacestodes dissected from infected pig meat. Adult worms were collected from hamster intestines of animals killed 5-60 days post-infection (dpi), incubated in RPMI 1640 medium with or without colchicine, fixed and processed for transmission electron microscopy (TEM). Sections for light microscopy from 40 different blocks with scolex, immature and mature proglottids were photographed. Thin sections were cut from 25 selected blocks, examined and photographed with TEM. Metaphase mitosis figures were observed in the subtegument of the germinative tissue and interpreted as germ cell precursors. In immature proglottids (20 dpi), discrete cell clusters of three to four cells surrounded by a thin cytoplasmic envelope were identified along the inner border of the lateral excretory ducts. These were also observed in more mature proglottids (40-60 dpi) as clusters of eight cells enclosed in a cytoplasmic envelope, with nuclei of spermatogonia exhibiting the synaptolems of primary meiotic cells. In mature proglottids from 45 dpi, a large number of spermatocyte lobules were found, exhibiting different stages of spermatogenesis from primary spermatocytes to mature filiform spermatids with a single axoneme, annular nucleus and spiral cortical microtubules, similar to spermatozoa described for type III spermiogenesis of species of the family Taeniidae. All mature spermatocyte lobules were enclosed in a highly organized cellular envelope and surrounded by a basal lamina. The envelopes contained a number of distinct organelles, seen in cross-section as discrete lattices of microtubules located between two layers of plasma membrane, as well as thickened furled cytoplasm with numerous strands of rough endoplasmic reticulum and pockets of microtubules.

  14. Spatial updating in human parietal cortex

    NASA Technical Reports Server (NTRS)

    Merriam, Elisha P.; Genovese, Christopher R.; Colby, Carol L.

    2003-01-01

    Single neurons in monkey parietal cortex update visual information in conjunction with eye movements. This remapping of stimulus representations is thought to contribute to spatial constancy. We hypothesized that a similar process occurs in human parietal cortex and that we could visualize it with functional MRI. We scanned subjects during a task that involved remapping of visual signals across hemifields. We observed an initial response in the hemisphere contralateral to the visual stimulus, followed by a remapped response in the hemisphere ipsilateral to the stimulus. We ruled out the possibility that this remapped response resulted from either eye movements or visual stimuli alone. Our results demonstrate that updating of visual information occurs in human parietal cortex.

  15. Left posterior-dorsal area 44 couples with parietal areas to promote speech fluency, while right area 44 activity promotes the stopping of motor responses.

    PubMed

    Neef, Nicole E; Bütfering, Christoph; Anwander, Alfred; Friederici, Angela D; Paulus, Walter; Sommer, Martin

    2016-11-15

    Area 44 is a cytoarchitectonically distinct portion of Broca's region. Parallel and overlapping large-scale networks couple with this region thereby orchestrating heterogeneous language, cognitive, and motor functions. In the context of stuttering, area 44 frequently comes into focus because structural and physiological irregularities affect developmental trajectories, stuttering severity, persistency, and etiology. A remarkable phenomenon accompanying stuttering is the preserved ability to sing. Speaking and singing are connatural behaviours recruiting largely overlapping brain networks including left and right area 44. Analysing which potential subregions of area 44 are malfunctioning in adults who stutter, and what effectively suppresses stuttering during singing, may provide a better understanding of the coordination and reorganization of large-scale brain networks dedicated to speaking and singing in general. We used fMRI to investigate functionally distinct subregions of area 44 during imagery of speaking and imaginary of humming a melody in 15 dextral males who stutter and 17 matched control participants. Our results are fourfold. First, stuttering was specifically linked to a reduced activation of left posterior-dorsal area 44, a subregion that is involved in speech production, including phonological word processing, pitch processing, working memory processes, sequencing, motor planning, pseudoword learning, and action inhibition. Second, functional coupling between left posterior area 44 and left inferior parietal lobule was deficient in stuttering. Third, despite the preserved ability to sing, males who stutter showed bilaterally a reduced activation of area 44 when imagine humming a melody, suggesting that this fluency-enhancing condition seems to bypass posterior-dorsal area 44 to achieve fluency. Fourth, time courses of the posterior subregions in area 44 showed delayed peak activations in the right hemisphere in both groups, possibly signaling the

  16. Apraxia, pantomime and the parietal cortex.

    PubMed

    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.

  17. Assessment of Cortical Dysfunction in Patients with Intermittent Exotropia: An fMRI Study

    PubMed Central

    Zhang, Junran; Gong, Qiyong; Liu, Longqian

    2016-01-01

    Neural imaging studies have found the connection between strabismus and brain cortex. However, the pathological mechanisms of intermittent exotropia are still not fully understood. In the present study, changes of binocular fusion related cortices in intermittent exotropia were investigated with blood oxygen level dependent functional magnetic resonance imaging. Activated cortices induced by fusion stimulus were found to be distributed in several regions such as bilateral middle occipital gyrus, bilateral middle temporal gyrus, left superior parietal lobule and so on. Compared with normal subjects, the increased activation intensity was observed in bilateral superior parietal lobule and inferior parietal lobule in subjects with intermittent exotropia. These findings indicate that binocular fusion involves a complicated brain network including several regions. And cortical activities of bilateral superior parietal lobule and inferior parietal lobule compensate for the binocular fusion dysfunction in intermittent exotropia. PMID:27501391

  18. Cortical connectivity suggests a role in limb coordination for macaque area PE of the superior parietal cortex.

    PubMed

    Bakola, Sophia; Passarelli, Lauretta; Gamberini, Michela; Fattori, Patrizia; Galletti, Claudio

    2013-04-10

    In macaques, superior parietal lobule area 5 has been described as occupying an extensive region, which includes the caudal half of the postcentral convexity as well as the medial bank of the intraparietal sulcus. Modern neuroanatomical methods have allowed the identification of various areas within this region. In the present study, we investigated the corticocortical afferent projections of one of these subdivisions, area PE. Our results demonstrate that PE, defined as a single architectonic area that contains a topographic map of the body, forms specific connections with somatic and motor fields. Thus, PE receives major afferents from parietal areas, mainly area 2, PEc, several areas in the medial bank of the intraparietal sulcus, opercular areas PGop/PFop, and the retroinsular area, frontal afferents from the primary motor cortex, the supplementary motor area, and the caudal subdivision of dorsal premotor cortex, as well as afferents from cingulate areas PEci, 23, and 24. The presence and relative strength of these connections depend on the location of injection sites, so that lateral PE receives preferential input from anterior sectors of the medial bank of intraparietal sulcus and from the ventral premotor cortex, whereas medial PE forms denser connections with area PEc and motor fields. In contrast with other posterior parietal areas, there are no projections to PE from occipital or prefrontal cortices. Overall, the sensory and motor afferents to PE are consistent with functions in goal-directed movement but also hint at a wider variety of motor coordination roles.

  19. Sulcus topography of the parietal opercular region: an anatomic and MR study.

    PubMed

    Steinmetz, H; Ebeling, U; Huang, Y X; Kahn, T

    1990-05-01

    The study describes the sulcal and gyral topography, variability, and left-right asymmetry of the parietal operculum. Eighty postmortem hemispheres as well as sagittal magnetic resonance images from 20 health volunteers (40 hemispheres) were evaluated. Four different types of parietal opercular sulcus topography were recognized. Most frequently, and conforming with the anatomic "textbook pattern", the inferior postcentral sulcus (POCS) is the sulcus anterior to the posterior ascending ramus (PAR) of the Sylvian fissure (type 1). Variations were the following: lack of a PAR (type 2), interposition of an intermediate opercular sulcus and gyrus between PAR and POCS (type 3), and direct transition of PAR into POCS with subsequent lack of a classical supramarginal gyrus (type 4). Inconstancy of the sulcal standard arrangement was especially pronounced among left hemispheres, where the patterns differed from type 1 in one third of the cases. Types 2 and 3 were significantly more frequent in left hemispheres, whereas type 4 occurred significantly more frequently in right hemispheres. Upon intraindividual left-right comparison, a remarkable 38% of the brains showed gross asymmetry of the parietal opercular sulcus patterns, characterized by a left type 2 or 3 and/or a right type 4; another 5% exhibited a reverse type of asymmetry. The findings supplement previous data on gross variability and left-right asymmetry of the posterior Sylvian fissure and its lower bank. They indicate that the Sylvian fissure is an unreliable landmark with respect to inferior parietal structures especially in left hemispheres. Individual mapping of perisylvian topography may contribute to studies on structural-functional relationship.

  20. A method for determination in situ of variations within the hepatic lobule of hepatocyte function and metabolite concentrations.

    PubMed Central

    Burns, S P; Cohen, R D; Iles, R A; Germain, J P; Going, T C; Evans, S J; Royston, P

    1996-01-01

    A method is described for the production of detailed maps of intralobular variations of hepatocyte function and metabolite concentrations, based on variable destruction by digitonin of the lobule from the centrilobular direction. Instead of the conventional approach, in which isolated hepatocytes are then prepared and studied in suspension, perfusion is continued after digitonin treatment and the function of the unaffected lobular remnants is determined, or mean metabolite concentrations are measured by 31P-NMR. These measurements are plotted against the degree of destruction, determined precisely after each study by automated quantitative histomorphometry. These plots are transformed into curves of the function or metabolite concentration of nominal single cells at any point along the radius of the lobule. Gluconeogenesis from lactate remained stable, although reduced, even after 85-90% lobular destruction, predominated periportally and disappeared by 50% along the radius of the lobule. In 31P-NMR studies, employing 1.5 mM lactate as substrate, narrowing of the intracellular P1 resonance was observed as digitonin destruction increased; this was attributed to a decrease in the intralobular heterogeneity of the intracellular pH, which fell from approx. 7.9 to < 7.4 along the first 16% of the lobular radius (from the periportal end) and to < 7.3 in the remainder of the lobule. The ATP concentration rose, and then fell, along the radius of the lobule in a centripetal direction. The method is potentially generally applicable to a wide range of hepatocellular functions and to the measurement of metabolite concentrations, most conveniently those susceptible to estimation by NMR. PMID:8912670

  1. Contribution of the posterior parietal cortex in reaching, grasping, and using objects and tools

    PubMed Central

    Vingerhoets, Guy

    2014-01-01

    Neuropsychological and neuroimaging data suggest a differential contribution of posterior parietal regions during the different components of a transitive gesture. Reaching requires the integration of object location and body position coordinates and reaching tasks elicit bilateral activation in different foci along the intraparietal sulcus. Grasping requires a visuomotor match between the object's shape and the hand's posture. Lesion studies and neuroimaging confirm the importance of the anterior part of the intraparietal sulcus for human grasping. Reaching and grasping reveal bilateral activation that is generally more prominent on the side contralateral to the hand used or the hemifield stimulated. Purposeful behavior with objects and tools can be assessed in a variety of ways, including actual use, pantomimed use, and pure imagery of manipulation. All tasks have been shown to elicit robust activation over the left parietal cortex in neuroimaging, but lesion studies have not always confirmed these findings. Compared to pantomimed or imagined gestures, actual object and tool use typically produces activation over the left primary somatosensory region. Neuroimaging studies on pantomiming or imagery of tool use in healthy volunteers revealed neural responses in possibly separate foci in the left supramarginal gyrus. In sum, the parietal contribution of reaching and grasping of objects seems to depend on a bilateral network of intraparietal foci that appear organized along gradients of sensory and effector preferences. Dorsal and medial parietal cortex appears to contribute to the online monitoring/adjusting of the ongoing prehensile action, whereas the functional use of objects and tools seems to involve the inferior lateral parietal cortex. This functional input reveals a clear left lateralized activation pattern that may be tuned to the integration of acquired knowledge in the planning and guidance of the transitive movement. PMID:24634664

  2. Neural correlates of relational reasoning and the symbolic distance effect: involvement of parietal cortex.

    PubMed

    Hinton, E C; Dymond, S; von Hecker, U; Evans, C J

    2010-06-16

    A novel, five-term relational reasoning paradigm was employed during functional magnetic resonance imaging to investigate neural correlates of the symbolic distance effect (SDE). Prior to scanning, participants learned a series of more-than (E>D>C>B>A) or less-than (AA) and nonadjacent one-step (AA, D>B and E>C) and two-step (AA and E>B) combinatorial entailed tasks. In terms of brain activation, the SDE was identified in the inferior frontal cortex, dorsolateral prefrontal cortex, and bilateral parietal cortex with a graded activation pattern from adjacent to one-step and two-step relations. We suggest that this captures the behavioural SDE of increased accuracy and decreased reaction time from adjacent to two-step relations. One-step relations involving endpoints A or E resulted in greater parietal activation compared to one-step relations without endpoints. Novel contrasts found enhanced activation in right parietal and prefrontal cortices during mutually entailed tasks only for participants who had learned all less-than relations. Increased parietal activation was found for one-step tasks that were inconsistent with prior training. Overall, the findings demonstrate a crucial role for parietal cortex during relational reasoning with a spatially ordered array.

  3. Monitoring for target objects: activation of right frontal and parietal cortices with increasing time on task.

    PubMed

    Coull, J T; Frackowiak, R S; Frith, C D

    1998-12-01

    The right prefrontal and parietal cortices have been implicated in attentional processing in both neuropsychological and functional neuroimaging literature. However, attention is a heterogeneous collection of processes, each of which may be underpinned by different neural networks. These attentional networks may interact, such that engaging one type of attentional process could influence the efficiency of another via overlapping neural substrates. We investigated the hypothesis that right frontal and parietal cortices provide the neuroanatomical location of the functional interaction between sustained attention and the process of selectively monitoring for target objects. Six healthy volunteers performed one of two tasks which required either selective or non-selective responding. The task lasted continuously for 18 min, during which time 3 Positron Emission Tomography (PET) scans were acquired for each task. This was repeated to obtain 12 PET measurements of regional cerebral blood flow (rCBF) for each subject. The right inferior frontal and parietal cortices were differentially activated by increasing time on task during the selective (S) vs non-selective (NS) task. Specifically, rCBF decreased with increasing time spent performing the NS task but not the S task. This result suggests that the normal deactivation in these areas as time on task increases is counteracted by the extra cognitive demands of selectively responding to target objects. Therefore, we have confirmed our hypothesis that right frontal and parietal cortices provide the neuroanatomical location for the modulation of object selection by sustained attention. We also identified the neuroanatomical correlates of each process separately, and confirmed earlier reports of prefrontal cortex and anterior cingulate activation associated with selective responding, and a fronto-parietal-thalamic network associated with sustained attention.

  4. From visual affordances in monkey parietal cortex to hippocampo-parietal interactions underlying rat navigation.

    PubMed Central

    Arbib, M A

    1997-01-01

    This paper explores the hypothesis that various subregions (but by no means all) of the posterior parietal cortex are specialized to process visual information to extract a variety of affordances for behaviour. Two biologically based models of regions of the posterior parietal cortex of the monkey are introduced. The model of the lateral intraparietal area (LIP) emphasizes its roles in dynamic remapping of the representation of targets during a double saccade task, and in combining stored, updated input with current visual input. The model of the anterior intraparietal area (AIP) addresses parietal-premotor interactions involved in grasping, and analyses the interaction between the AIP and premotor area F5. The model represents the role of other intraparietal areas working in concert with the inferotemporal cortex as well as with corollary discharge from F5 to provide and augment the affordance information in the AIP, and suggests how various constraints may resolve the action opportunities provided by multiple affordances. Finally, a systems-level model of hippocampo parietal interactions underlying rat navigation is developed, motivated by the monkey data used in developing the above two models as well as by data on neurones in the posterior parietal cortex of the monkey that are sensitive to visual motion. The formal similarity between dynamic remapping (primate saccades) and path integration (rat navigation) is noted, and certain available data on rat posterior parietal cortex in terms of affordances for locomotion are explained. The utility of further modelling, linking the World Graph model of cognitive maps for motivated behaviour with hippocampal-parietal interactions involved in navigation, is also suggested. These models demonstrate that posterior parietal cortex is not only itself a network of interacting subsystems, but functions through cooperative computation with many other brain regions. PMID:9368931

  5. Beyond natural numbers: negative number representation in parietal cortex.

    PubMed

    Blair, Kristen P; Rosenberg-Lee, Miriam; Tsang, Jessica M; Schwartz, Daniel L; Menon, Vinod

    2012-01-01

    Unlike natural numbers, negative numbers do not have natural physical referents. How does the brain represent such abstract mathematical concepts? Two competing hypotheses regarding representational systems for negative numbers are a rule-based model, in which symbolic rules are applied to negative numbers to translate them into positive numbers when assessing magnitudes, and an expanded magnitude model, in which negative numbers have a distinct magnitude representation. Using an event-related functional magnetic resonance imaging design, we examined brain responses in 22 adults while they performed magnitude comparisons of negative and positive numbers that were quantitatively near (difference <4) or far apart (difference >6). Reaction times (RTs) for negative numbers were slower than positive numbers, and both showed a distance effect whereby near pairs took longer to compare. A network of parietal, frontal, and occipital regions were differentially engaged by negative numbers. Specifically, compared to positive numbers, negative number processing resulted in greater activation bilaterally in intraparietal sulcus (IPS), middle frontal gyrus, and inferior lateral occipital cortex. Representational similarity analysis revealed that neural responses in the IPS were more differentiated among positive numbers than among negative numbers, and greater differentiation among negative numbers was associated with faster RTs. Our findings indicate that despite negative numbers engaging the IPS more strongly, the underlying neural representation are less distinct than that of positive numbers. We discuss our findings in the context of the two theoretical models of negative number processing and demonstrate how multivariate approaches can provide novel insights into abstract number representation.

  6. Effective brain connectivity in children with reading difficulties during phonological processing.

    PubMed

    Cao, Fan; Bitan, Tali; Booth, James R

    2008-11-01

    Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age=12.4, range: 8.11-14.10) and 12 control children (M age=12.3, range: 8.9-14.11) during rhyming judgments to visually presented words. More difficult conflicting trials either had similar orthography but different phonology (e.g. pint-mint) or similar phonology but different orthography (e.g. jazz-has). Easier non-conflicting trials had similar orthography and phonology (e.g. dime-lime) or different orthography and phonology (e.g. staff-gain). The modulatory effect from left fusiform gyrus to left inferior parietal lobule was stronger in controls than in children with reading difficulties only for conflicting trials. Modulatory effects from left fusiform gyrus and left inferior parietal lobule to left inferior frontal gyrus were stronger for conflicting trials than for non-conflicting trials only in control children but not in children with reading difficulties. Modulatory effects from left inferior frontal gyrus to inferior parietal lobule, from medial frontal gyrus to left inferior parietal lobule, and from left inferior parietal lobule to medial frontal gyrus were positively correlated with reading skill only in control children. These findings suggest that children with reading difficulties have deficits in integrating orthography and phonology utilizing left inferior parietal lobule, and in engaging phonological rehearsal/segmentation utilizing left inferior frontal gyrus possibly through the indirect pathway connecting posterior to anterior language processing regions, especially when the orthographic and phonological information is conflicting.

  7. Cerebellar lobules and dentate nuclei mirror cortical force-related-BOLD responses: Beyond all (linear) expectations.

    PubMed

    Alahmadi, Adnan A S; Pardini, Matteo; Samson, Rebecca S; Friston, Karl J; Toosy, Ahmed T; D'Angelo, Egidio; Gandini Wheeler-Kingshott, Claudia A M

    2017-02-27

    The relationship between the BOLD response and an applied force was quantified in the cerebellum using a power grip task. To investigate whether the cerebellum responds in an on/off way to motor demands or contributes to motor responses in a parametric fashion, similarly to the cortex, five grip force levels were investigated under visual feedback. Functional MRI data were acquired in 13 healthy volunteers and their responses were analyzed using a cerebellum-optimized pipeline. This allowed us to evaluate, within the cerebellum, voxelwise linear and non-linear associations between cerebellar activations and forces. We showed extensive non-linear activations (with a parametric design), covering the anterior and posterior lobes of the cerebellum with a BOLD-force relationship that is region-dependent. Linear responses were mainly located in the anterior lobe, similarly to the cortex, where linear responses are localized in M1. Complex responses were localized in the posterior lobe, reflecting its key role in attention and executive processing, required during visually guided movement. Given the highly organized responses in the cerebellar cortex, a key question is whether deep cerebellar nuclei show similar parametric effects. We found positive correlations with force in the ipsilateral dentate nucleus and negative correlations on the contralateral side, suggesting a somatotopic organization of the dentate nucleus in line with cerebellar and cortical areas. Our results confirm that there is cerebellar organization involving all grey matter structures that reflect functional segregation in the cortex, where cerebellar lobules and dentate nuclei contribute to complex motor tasks with different BOLD response profiles in relation to the forces. Hum Brain Mapp, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  8. Electrocorticography reveals the temporal dynamics of posterior parietal cortical activity during recognition memory decisions

    PubMed Central

    Gonzalez, Alex; Hutchinson, J. Benjamin; Uncapher, Melina R.; Chen, Janice; LaRocque, Karen F.; Foster, Brett L.; Rangarajan, Vinitha; Parvizi, Josef; Wagner, Anthony D.

    2015-01-01

    Theories of the neurobiology of episodic memory predominantly focus on the contributions of medial temporal lobe structures, based on extensive lesion, electrophysiological, and imaging evidence. Against this backdrop, functional neuroimaging data have unexpectedly implicated left posterior parietal cortex (PPC) in episodic retrieval, revealing distinct activation patterns in PPC subregions as humans make memory-related decisions. To date, theorizing about the functional contributions of PPC has been hampered by the absence of information about the temporal dynamics of PPC activity as retrieval unfolds. Here, we leveraged electrocorticography to examine the temporal profile of high gamma power (HGP) in dorsal PPC subregions as participants made old/new recognition memory decisions. A double dissociation in memory-related HGP was observed, with activity in left intraparietal sulcus (IPS) and left superior parietal lobule (SPL) differing in time and sign for recognized old items (Hits) and correctly rejected novel items (CRs). Specifically, HGP in left IPS increased for Hits 300–700 ms poststimulus onset, and decayed to baseline ∼200 ms preresponse. By contrast, HGP in left SPL increased for CRs early after stimulus onset (200−300 ms) and late in the memory decision (from 700 ms to response). These memory-related effects were unique to left PPC, as they were not observed in right PPC. Finally, memory-related HGP in left IPS and SPL was sufficiently reliable to enable brain-based decoding of the participant’s memory state at the single-trial level, using multivariate pattern classification. Collectively, these data provide insights into left PPC temporal dynamics as humans make recognition memory decisions. PMID:26283375

  9. Simulation of the Inferior Mirage

    NASA Astrophysics Data System (ADS)

    Branca, Mario

    2010-09-01

    A mirage can occur when a continuous variation in the refractive index of the air causes light rays to follow a curved path. As a result, the image we see is displaced from the location of the object. If the image appears higher in the air than the object, it is called a "superior" mirage, while if it appears lower it is called an "inferior" mirage.2 The most common example of an inferior mirage is when, on a hot day, a stretch of dry road off in the distance appears to be wet (see Fig. 1). Many lab activities have been described that simulate the formation of superior mirages. In these demonstrations light beams curve downward as they pass through a nonuni-form fluid.3-6 Much less common are laboratory demonstrations of upward-curving light rays of the kind responsible for inferior mirages. This paper describes a simple version of such a demonstration.

  10. Autologus parietal grafts in preprosthethic surgery

    PubMed Central

    GHERLONE, E.F.; VINCI, R.; D’AVERSA, L.

    2010-01-01

    SUMMARY Edentulous patients usually request implant supported/fixed rehabilitation. Ridge resorption after teeth loss usually affect three-dimensional implant position. Vertical and/or horizontal bone augmentation procedures are often the only choice the clinician has to deliver prosthetic guided restoration. Gold standard for augmentation procedures such as sinus lift, onlay or inlay grafts, is still autologous bone. The patient in this report underwent a pre-prosthetic reconstruction of the jaws with parietal bone, followed by fixtures insertion and fixed prosthetic rehabilitation. This clinical report aims to underline the importance of multidisciplinary treatment to optimize the results of the rehabilitation. PMID:23285358

  11. Transcriptional Landscape of Glomerular Parietal Epithelial Cells

    PubMed Central

    Gharib, Sina A.; Pippin, Jeffrey W.; Ohse, Takamoto; Pickering, Scott G.; Krofft, Ronald D.; Shankland, Stuart J.

    2014-01-01

    Very little is known about the function of glomerular parietal epithelial cells (PECs). In this study, we performed genome-wide expression analysis on PEC-enriched capsulated vs. PEC-deprived decapsulated rat glomeruli to determine the transcriptional state of PECs under normal conditions. We identified hundreds of differentially expressed genes that mapped to distinct biologic modules including development, tight junction, ion transport, and metabolic processes. Since developmental programs were highly enriched in PECs, we characterized several of their candidate members at the protein level. Collectively, our findings confirm that PECs are multifaceted cells and help define their diverse functional repertoire. PMID:25127402

  12. Multisensory Interactions Influence Neuronal Spike Train Dynamics in the Posterior Parietal Cortex

    PubMed Central

    VanGilder, Paul; Shi, Ying; Apker, Gregory; Dyson, Keith; Buneo, Christopher A.

    2016-01-01

    Although significant progress has been made in understanding multisensory interactions at the behavioral level, their underlying neural mechanisms remain relatively poorly understood in cortical areas, particularly during the control of action. In recent experiments where animals reached to and actively maintained their arm position at multiple spatial locations while receiving either proprioceptive or visual-proprioceptive position feedback, multisensory interactions were shown to be associated with reduced spiking (i.e. subadditivity) as well as reduced intra-trial and across-trial spiking variability in the superior parietal lobule (SPL). To further explore the nature of such interaction-induced changes in spiking variability we quantified the spike train dynamics of 231 of these neurons. Neurons were classified as Poisson, bursty, refractory, or oscillatory (in the 13–30 Hz “beta-band”) based on their spike train power spectra and autocorrelograms. No neurons were classified as Poisson-like in either the proprioceptive or visual-proprioceptive conditions. Instead, oscillatory spiking was most commonly observed with many neurons exhibiting these oscillations under only one set of feedback conditions. The results suggest that the SPL may belong to a putative beta-synchronized network for arm position maintenance and that position estimation may be subserved by different subsets of neurons within this network depending on available sensory information. In addition, the nature of the observed spiking variability suggests that models of multisensory interactions in the SPL should account for both Poisson-like and non-Poisson variability. PMID:28033334

  13. Functional organization of human posterior parietal cortex: grasping- and reaching-related activations relative to topographically organized cortex

    PubMed Central

    Konen, Christina S.; Mruczek, Ryan E. B.; Montoya, Jessica L.

    2013-01-01

    The act of reaching to grasp an object requires the coordination between transporting the arm and shaping the hand. Neurophysiological, neuroimaging, neuroanatomic, and neuropsychological studies in macaque monkeys and humans suggest that the neural networks underlying grasping and reaching acts are at least partially separable within the posterior parietal cortex (PPC). To better understand how these neural networks have evolved in primates, we characterized the relationship between grasping- and reaching-related responses and topographically organized areas of the human intraparietal sulcus (IPS) using functional MRI. Grasping-specific activation was localized to the left anterior IPS, partially overlapping with the most anterior topographic regions and extending into the postcentral sulcus. Reaching-specific activation was localized to the left precuneus and superior parietal lobule, partially overlapping with the medial aspects of the more posterior topographic regions. Although the majority of activity within the topographic regions of the IPS was nonspecific with respect to movement type, we found evidence for a functional gradient of specificity for reaching and grasping movements spanning posterior-medial to anterior-lateral PPC. In contrast to the macaque monkey, grasp- and reach-specific activations were largely located outside of the human IPS. PMID:23515795

  14. Prolonged ictal monoparesis with parietal Periodic Lateralised Epileptiform Discharges (PLEDs).

    PubMed

    Murahara, Takashi; Kinoshita, Masako; Usami, Kiyohide; Matsui, Masashi; Yamashita, Kouhei; Takahashi, Ryosuke; Ikeda, Akio

    2013-06-01

    We report a patient with prolonged monoparesis and parietal periodic lateralised epileptiform discharges (PLEDs). The patient was a 73-year-old man with chronic myelomonocytic leukaemia who developed persisting monoparesis of the right arm, sensory aphasia, and finger agnosia, initially associated with focal clonic seizures. These neurological deficits remained for seven days without subsequent focal clonic seizures. The EEG showed left-sided PLEDs, maximal in the left occipito-parietal area. Ten days later, following phenytoin treatment, these symptoms suddenly improved and parietal PLEDs disappeared. Sustained PLEDs in the left parietal region may have been causally associated with ictal paresis in this patient.

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

    PubMed

    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.

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

    PubMed

    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.

  17. Muscarinic responses of gastric parietal cells

    SciTech Connect

    Wilkes, J.M.; Kajimura, M.; Scott, D.R.; Hersey, S.J.; Sachs, G. )

    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.

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

    PubMed

    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

  19. Simulation of the Inferior Mirage

    ERIC Educational Resources Information Center

    Branca, Mario

    2010-01-01

    A mirage can occur when a continuous variation in the refractive index of the air causes light rays to follow a curved path. As a result, the image we see is displaced from the location of the object. If the image appears higher in the air than the object, it is called a "superior" mirage, while if it appears lower it is called an "inferior"…

  20. Mandatory Housing Requirements: The Constitutionality of Parietal Rules

    ERIC Educational Resources Information Center

    Iowa Law Review, 1975

    1975-01-01

    Analyzes the validity of parietal rules under both the due process and equal protection clauses of the Fourteenth Amendment. Models of substantive due process and equal protection are developed and applied to the various types of parietal rules that have been implemented at universities throughout the nation. (Author/JT)

  1. The Role of Human Parietal Cortex in Attention Networks

    ERIC Educational Resources Information Center

    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…

  2. Agnosia for Mirror Stimuli: A New Case Report with a Small Parietal Lesion

    PubMed Central

    Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Lebas, Axel; Gerardin, Emmanuel; Hannequin, Didier

    2014-01-01

    Only seven cases of agnosia for mirror stimuli have been reported, always with an extensive lesion. We report a new case of an agnosia for mirror stimuli due to a circumscribed lesion. An extensive battery of neuropsychological tests and a new experimental procedure to assess visual object mirror and orientation discrimination were assessed 10 days after the onset of clinical symptoms, and 5 years later. The performances of our patient were compared with those of four healthy control subjects matched for age. This test revealed an agnosia for mirror stimuli. Brain imaging showed a small right occipitoparietal hematoma, encompassing the extrastriate cortex adjoining the inferior parietal lobe. This new case suggests that: (i) agnosia for mirror stimuli can persist for 5 years after onset and (ii) the posterior part of the right intraparietal sulcus could be critical in the cognitive process of mirror stimuli discrimination. PMID:25037846

  3. Agnosia for mirror stimuli: a new case report with a small parietal lesion.

    PubMed

    Martinaud, Olivier; Mirlink, Nicolas; Bioux, Sandrine; Bliaux, Evangéline; Lebas, Axel; Gerardin, Emmanuel; Hannequin, Didier

    2014-11-01

    Only seven cases of agnosia for mirror stimuli have been reported, always with an extensive lesion. We report a new case of an agnosia for mirror stimuli due to a circumscribed lesion. An extensive battery of neuropsychological tests and a new experimental procedure to assess visual object mirror and orientation discrimination were assessed 10 days after the onset of clinical symptoms, and 5 years later. The performances of our patient were compared with those of four healthy control subjects matched for age. This test revealed an agnosia for mirror stimuli. Brain imaging showed a small right occipitoparietal hematoma, encompassing the extrastriate cortex adjoining the inferior parietal lobe. This new case suggests that: (i) agnosia for mirror stimuli can persist for 5 years after onset and (ii) the posterior part of the right intraparietal sulcus could be critical in the cognitive process of mirror stimuli discrimination.

  4. Compensatory fronto-parietal hyperactivation during set-shifting in unmedicated patients with Parkinson's disease.

    PubMed

    Gerrits, Niels J H M; van der Werf, Ysbrand D; Verhoef, Kim M W; Veltman, Dick J; Groenewegen, Henk J; Berendse, Henk W; van den Heuvel, Odile A

    2015-02-01

    Patients with Parkinson's disease (PD) often suffer from impairments in executive functions, such as mental rigidity, which can be measured as impaired set-shifting. Previous studies have shown that set-shifting deficits in patients with PD result from hypo-excitation of the caudate nucleus and lateral prefrontal cortices. The results of these studies may have been influenced by the inclusion of patients on dopaminergic medication, and by choosing set-shifting paradigms in which performance also depends on other cognitive mechanisms, such as matching-to-sample. To circumvent these potential confounding factors, we tested patients with PD that were not on dopamine replacement therapy, and we developed a new feedback-based paradigm to measure the cognitive construct set-shifting more accurately. In this case-control study, 18 patients with PD and 35 well-matched healthy controls performed the set-shifting task, while task-related neural activation was recorded using functional magnetic resonance imaging. Behaviourally, PD patients, compared with healthy controls, made more errors during repeat trials, but not set-shift trials. The patients, compared with controls, showed increased task-related activation of the bilateral inferior parietal cortex, and the right superior frontal gyrus, and decreased activation of the right ventrolateral prefrontal cortex during set-shift trials. Our findings suggest that, despite decreased task-related activation of the right ventrolateral prefrontal cortex, these early-stage unmedicated patients with PD do not yet suffer from set-shifting deficits due to compensatory hyperactivation in the inferior parietal cortex and the superior frontal gyrus.

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

    PubMed Central

    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

  6. Dissociable effects of surprise and model update in parietal and anterior cingulate cortex

    PubMed Central

    O’Reilly, Jill X.; Schüffelgen, Urs; Cuell, Steven F.; Behrens, Timothy E. J.; Mars, Rogier B.; Rushworth, Matthew F. S.

    2013-01-01

    Brains use predictive models to facilitate the processing of expected stimuli or planned actions. Under a predictive model, surprising (low probability) stimuli or actions necessitate the immediate reallocation of processing resources, but they can also signal the need to update the underlying predictive model to reflect changes in the environment. Surprise and updating are often correlated in experimental paradigms but are, in fact, distinct constructs that can be formally defined as the Shannon information (IS) and Kullback–Leibler divergence (DKL) associated with an observation. In a saccadic planning task, we observed that distinct behaviors and brain regions are associated with surprise/IS and updating/DKL. Although surprise/IS was associated with behavioral reprogramming as indexed by slower reaction times, as well as with activity in the posterior parietal cortex [human lateral intraparietal area (LIP)], the anterior cingulate cortex (ACC) was specifically activated during updating of the predictive model (DKL). A second saccade-sensitive region in the inferior posterior parietal cortex (human 7a), which has connections to both LIP and ACC, was activated by surprise and modulated by updating. Pupillometry revealed a further dissociation between surprise and updating with an early positive effect of surprise and late negative effect of updating on pupil area. These results give a computational account of the roles of the ACC and two parietal saccade regions, LIP and 7a, by which their involvement in diverse tasks can be understood mechanistically. The dissociation of functional roles between regions within the reorienting/reprogramming network may also inform models of neurological phenomena, such as extinction and Balint syndrome, and neglect. PMID:23986499

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

    PubMed

    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.

  8. Damage to temporo-parietal cortex decreases incidental activation of thematic relations during spoken word comprehension.

    PubMed

    Mirman, Daniel; Graziano, Kristen M

    2012-07-01

    Both taxonomic and thematic semantic relations have been studied extensively in behavioral studies and there is an emerging consensus that the anterior temporal lobe plays a particularly important role in the representation and processing of taxonomic relations, but the neural basis of thematic semantics is less clear. We used eye tracking to examine incidental activation of taxonomic and thematic relations during spoken word comprehension in participants with aphasia. Three groups of participants were tested: neurologically intact control participants (N=14), individuals with aphasia resulting from lesions in left hemisphere BA 39 and surrounding temporo-parietal cortex regions (N=7), and individuals with the same degree of aphasia severity and semantic impairment and anterior left hemisphere lesions (primarily inferior frontal gyrus and anterior temporal lobe) that spared BA 39 (N=6). The posterior lesion group showed reduced and delayed activation of thematic relations, but not taxonomic relations. In contrast, the anterior lesion group exhibited longer-lasting activation of taxonomic relations and did not differ from control participants in terms of activation of thematic relations. These results suggest that taxonomic and thematic semantic knowledge are functionally and neuroanatomically distinct, with the temporo-parietal cortex playing a particularly important role in thematic semantics.

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

    PubMed Central

    Grosbras, Marie-Hélène

    2016-01-01

    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 to scan participants while they performed saccades toward targets at either short (4°) or large (30°) eccentricity. A regional multivoxel pattern analysis reveals that patterns of activity in the frontal eye-field 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. PMID:27833536

  10. Uncertain relational reasoning in the parietal cortex.

    PubMed

    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.

  11. INTERDEPENDENT SUPERIORITY AND INFERIORITY FEELINGS

    PubMed Central

    Ingham, Harrington V.

    1949-01-01

    It is postulated that in neurotic persons who have unrealistic feelings of superiority and inferiority the two are interdependent. This is a departure from the concept of previous observers that either one or the other is primary and its opposite is overcompensation. The author postulates considerable parallelism, with equal importance for each. He submits that the neurotic person forms two logic-resistant compartments for the two opposed self-estimates and that treatment which makes inroads of logic upon one compartment, simultaneously does so upon the other. Two examples are briefly reported. The neurotic benefits sought in exaggeration of capability are the same as those sought in insistence upon inferiority: Presumption of superiority at once bids for approbation and delivers the subject from the need to prove himself worthy of it in dreaded competition; exaggeration of incapability baits sympathy and makes competition unnecessary because failure is conceded. Some of the characteristics of abnormal self-estimates that distinguish them from normal are: Preoccupation with self, resistance to logical explanation of personality problems, inconsistency in reasons for beliefs in adequacy on the one hand and inadequacy on the other, unreality, rationalization of faults, and difficulty and vacillation in the selection of adequate goals. PMID:15390573

  12. Parietal contributions to visual working memory depend on task difficulty.

    PubMed

    Jones, Kevin T; Berryhill, Marian E

    2012-01-01

    The nature of parietal contributions to working memory (WM) remain poorly understood but of considerable interest. We previously reported that posterior parietal damage selectively impaired WM probed by recognition (Berryhill and Olson, 2008a). Recent studies provided support using a neuromodulatory technique, transcranial direct current stimulation (tDCS) applied to the right parietal cortex (P4). These studies confirmed parietal involvement in WM because parietal tDCS altered WM performance: anodal current tDCS improved performance in a change detection task, and cathodal current tDCS impaired performance on a sequential presentation task. Here, we tested whether these complementary results were due to different degrees of parietal involvement as a function of WM task demands, WM task difficulty, and/or participants' WM capacity. In Experiment 1, we applied cathodal and anodal tDCS to the right parietal cortex and tested participants on both previously used WM tasks. We observed an interaction between tDCS (anodal, cathodal), WM task difficulty, and participants' WM capacity. When the WM task was difficult, parietal stimulation (anodal or cathodal) improved WM performance selectively in participants with high WM capacity. In the low WM capacity group, parietal stimulation (anodal or cathodal) impaired WM performance. These nearly equal and opposite effects were only observed when the WM task was challenging, as in the change detection task. Experiment 2 probed the interplay of WM task difficulty and WM capacity in a parametric manner by varying set size in the WM change detection task. Here, the effect of parietal stimulation (anodal or cathodal) on the high WM capacity group followed a linear function as WM task difficulty increased with set size. The low WM capacity participants were largely unaffected by tDCS. These findings provide evidence that parietal involvement in WM performance depends on both WM capacity and WM task demands. We discuss these findings

  13. Parietal neural prosthetic control of a computer cursor in a graphical-user-interface task

    NASA Astrophysics Data System (ADS)

    Revechkis, Boris; Aflalo, Tyson NS; Kellis, Spencer; Pouratian, Nader; Andersen, Richard A.

    2014-12-01

    Objective. To date, the majority of Brain-Machine Interfaces have been used to perform simple tasks with sequences of individual targets in otherwise blank environments. In this study we developed a more practical and clinically relevant task that approximated modern computers and graphical user interfaces (GUIs). This task could be problematic given the known sensitivity of areas typically used for BMIs to visual stimuli, eye movements, decision-making, and attentional control. Consequently, we sought to assess the effect of a complex, GUI-like task on the quality of neural decoding. Approach. A male rhesus macaque monkey was implanted with two 96-channel electrode arrays in area 5d of the superior parietal lobule. The animal was trained to perform a GUI-like ‘Face in a Crowd’ task on a computer screen that required selecting one cued, icon-like, face image from a group of alternatives (the ‘Crowd’) using a neurally controlled cursor. We assessed whether the crowd affected decodes of intended cursor movements by comparing it to a ‘Crowd Off’ condition in which only the matching target appeared without alternatives. We also examined if training a neural decoder with the Crowd On rather than Off had any effect on subsequent decode quality. Main results. Despite the additional demands of working with the Crowd On, the animal was able to robustly perform the task under Brain Control. The presence of the crowd did not itself affect decode quality. Training the decoder with the Crowd On relative to Off had no negative influence on subsequent decoding performance. Additionally, the subject was able to gaze around freely without influencing cursor position. Significance. Our results demonstrate that area 5d recordings can be used for decoding in a complex, GUI-like task with free gaze. Thus, this area is a promising source of signals for neural prosthetics that utilize computing devices with GUI interfaces, e.g. personal computers, mobile devices, and tablet

  14. Impact of Cannabis Use on Prefrontal and Parietal Cortex Gyrification and Surface Area in Adolescents and Emerging Adults

    PubMed Central

    Shollenbarger, Skyler G.; Price, Jenessa; Wieser, Jon; Lisdahl, Krista

    2017-01-01

    Background Regions undergoing maturation with CB1 receptors may be at increased risk for cannabis-induced alterations. Here, we examine the relationships between cannabis use and prefrontal (PFC) and inferior parietal gyrification and surface area (SA) in youth. Methods Participants included 33 cannabis users and 35 controls (ages 18–25). Exclusions included co-morbid psychiatric/neurologic disorders and heavy other drug use. Multiple regressions and Pearson r correlations examined the effects of cannabis use on gyrification, SA and cognition. Results Cannabis use was associated with decreased gyrification in: ventral-medial PFC (RH: [FDR corrected p=.02] LH: [FDR corrected p=.02]); medial PFC (RH: [FDR corrected p=.02], LH: [FDR corrected p=.02]); and frontal poles (RH: [FDR corrected p=.02], LH: [FDR corrected p=.02]). No differences were observed in bilateral hemispheres, PFC, dorsolateral, ventrolateral, or inferior parietal ROIs. Cannabis use was associated with marginally decreased SA in left: medial PFC [FDR corrected p=.09], and ventral lateral PFC: [FDR corrected p=.09]. In cannabis users, increased gyrification was associated with improved working-memory performance in right medial (p=.003), ventral-medial (p=.03), and frontal pole ROIs (p=.007). Conclusions Cannabis use was associated with reduced gyrification in PFC regions implicated in self-referential thought and social cognition. Results suggest that these gyrification characteristics may have cognitive implications. PMID:26233614

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

    PubMed

    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.

  16. Shape recognition and inferior temporal neurons.

    PubMed Central

    Schwartz, E L; Desimone, R; Albright, T D; Gross, C G

    1983-01-01

    Inferior temporal cortex plays an important role in shape recognition. To study the shape selectivity of single inferior temporal neurons, we recorded their responses to a set of shapes systematically varying in boundary curvature. Many inferior temporal neurons were selective for stimuli of specific boundary curvature and maintained this selectivity over changes in stimulus size or position. The method of describing boundary curvature was that of Fourier descriptors. PMID:6577453

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

    PubMed Central

    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. PMID:22792493

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

    PubMed

    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.

  19. Content Specific Fronto-Parietal Synchronization during Visual Working Memory

    PubMed Central

    Salazar, RF; Dotson, NM; Bressler, SL; Gray, CM

    2014-01-01

    Lateral prefrontal and posterior parietal cortical areas exhibit task-dependent activation during working memory tasks in humans and monkeys. Neurons in these regions become synchronized during attention demanding tasks, but the contribution of these interactions to working memory is largely unknown. Using simultaneous recordings of neural activity from multiple areas in both regions, we find widespread, task-dependent and content specific synchronization of activity across the fronto-parietal network during visual working memory. The patterns of synchronization are prevalent among stimulus selective neurons and are governed by influences arising in parietal cortex. These results indicate that short-term memories are represented by large-scale patterns of synchronized activity across the fronto-parietal network. PMID:23118014

  20. The Repetition Paradigm: Enhancement of Novel Metaphors and Suppression of Conventional Metaphors in the Left Inferior Parietal Lobe

    ERIC Educational Resources Information Center

    Subramaniam, Karuna; Faust, Miriam; Beeman, Mark; Mashal, Nira

    2012-01-01

    The neural mechanisms underlying the process of understanding novel and conventional metaphoric expressions remain unclear largely because the specific brain regions that support the formation of novel semantic relations are still unknown. A well established way to study distinct cognitive processes specifically associated with an event of…

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

    PubMed

    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.

  2. Parietal and frontal eye field neglect in the rat.

    PubMed

    Crowne, D P; Richardson, C M; Dawson, K A

    1986-12-01

    Rats were given unilateral aspiration lesions of parietal, medial frontal, or dorsolateral frontal (motor) cortex and then tested for visual, auditory and tactile neglect, and for circling. All medial frontal lesion animals showed contralateral neglect in each modality and circled ipsiversively. The parietal lesion rats initially displayed contralateral visual and auditory neglect as severe as that in the medial frontal group. Three weeks after the lesions, the parietal group had a smaller residual deficit on the visual test than the medial frontal group. In the first week, parietal animals responded less than the medial frontals to stroking the vibrissae but were more responsive to mild pinching of a toe contralateral to the lesion side. In striking contrast to the medial frontal animals, the parietal group circled strongly to the contralateral side. No rat with a motor cortex lesion neglected or circled preferentially. Like medial frontal cortex, unilateral parietal lesions also produce neglect and circling, but there are important features distinguishing unilateral lesion effects in these two regions.

  3. Inferior vena caval masses identified by echocardiography

    NASA Technical Reports Server (NTRS)

    Sun, J. P.; Asher, C. R.; Xu, Y.; Huang, V.; Griffin, B. P.; Stewart, W. J.; Novick, A. C.; Thomas, J. D.

    1999-01-01

    The most common cause of an inferior vena caval mass is renal cell carcinoma that extends through the lumen, occurring in 47 of 62 patients (85%). Detection of an inferior vena caval mass affects the surgical approach requiring cardiopulmonary bypass for resection when the mass extends to the heart.

  4. Bilateral inferior petrosal sinus sampling.

    PubMed

    Zampetti, Benedetta; Grossrubatscher, Erika; Dalino Ciaramella, Paolo; Boccardi, Edoardo; Loli, Paola

    2016-07-01

    Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres.

  5. Bilateral inferior petrosal sinus sampling

    PubMed Central

    Grossrubatscher, Erika; Dalino Ciaramella, Paolo; Boccardi, Edoardo

    2016-01-01

    Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing’s syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88–100% and 67–100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50–70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres. PMID:27352844

  6. Prefrontal and parietal correlates of cognitive control related to the adult outcome of attention-deficit/hyperactivity disorder diagnosed in childhood.

    PubMed

    Schulz, Kurt P; Li, Xiaobo; Clerkin, Suzanne M; Fan, Jin; Berwid, Olga G; Newcorn, Jeffrey H; Halperin, Jeffrey M

    2017-02-20

    The protracted and highly variable development of prefrontal cortex regions that support cognitive control has been purported to shape the adult outcome of attention-deficit/hyperactivity disorder (ADHD). This neurodevelopmental model was tested in a prospectively followed sample of 27 adult probands who were diagnosed with ADHD in childhood and 28 carefully matched comparison subjects aged 21-28 years. Probands were classified with persistent ADHD or remitted ADHD. Behavioral and neural responses to the Stimulus and Response Conflict Task (SRCT) performed during functional magnetic resonance imaging (fMRI) were compared in probands and comparison subjects and in probands with persistent and remitted ADHD. Response speed and accuracy for stimulus, response, and combined conflicts did not differ across groups. Orbitofrontal, inferior frontal and parietal activation was lower in probands than comparison subjects, but only for combined conflicts, when demand for cognitive control was highest. Reduced activation for combined conflicts in probands was almost wholly attributable to the persistence of ADHD; orbitofrontal, inferior frontal, anterior cingulate and parietal activation was lower in probands with persistent ADHD than both probands with remitted ADHD and comparison subjects, but did not differ between probands with remitted ADHD and comparison subjects. These data provide the first evidence that prefrontal and parietal activation during cognitive control parallels the adult outcome of ADHD diagnosed in childhood, with persistence of symptoms linked to reduced activation and symptom recovery associated with activation indistinguishable from adults with no history of ADHD.

  7. Inferior alveolar nerve block: Alternative technique

    PubMed Central

    Thangavelu, K.; Kannan, R.; Kumar, N. Senthil

    2012-01-01

    Background: Inferior alveolar nerve block (IANB) is a technique of dental anesthesia, used to produce anesthesia of the mandibular teeth, gingivae of the mandible and lower lip. The conventional IANB is the most commonly used the nerve block technique for achieving local anesthesia for mandibular surgical procedures. In certain cases, however, this nerve block fails, even when performed by the most experienced clinician. Therefore, it would be advantageous to find an alternative simple technique. Aim and Objective: The objective of this study is to find an alternative inferior alveolar nerve block that has a higher success rate than other routine techniques. To this purpose, a simple painless inferior alveolar nerve block was designed to anesthetize the inferior alveolar nerve. Materials and Methods: This study was conducted in Oral surgery department of Vinayaka Mission's dental college Salem from May 2009 to May 2011. Five hundred patients between the age of 20 years and 65 years who required extraction of teeth in mandible were included in the study. Out of 500 patients 270 were males and 230 were females. The effectiveness of the IANB was evaluated by using a sharp dental explorer in the regions innervated by the inferior alveolar, lingual, and buccal nerves after 3, 5, and 7 min, respectively. Conclusion: This study concludes that inferior alveolar nerve block is an appropriate alternative nerve block to anesthetize inferior alveolar nerve due to its several advantages. PMID:25885503

  8. Material-dependent and material-independent selection processes in the frontal and parietal lobes: an event-related fMRI investigation of response competition

    NASA Technical Reports Server (NTRS)

    Hazeltine, Eliot; Bunge, Silvia A.; Scanlon, Michael D.; Gabrieli, John D E.

    2003-01-01

    The present study used the flanker task [Percept. Psychophys. 16 (1974) 143] to identify neural structures that support response selection processes, and to determine which of these structures respond differently depending on the type of stimulus material associated with the response. Participants performed two versions of the flanker task while undergoing event-related functional magnetic resonance imaging (fMRI). Both versions of the task required participants to respond to a central stimulus regardless of the responses associated with simultaneously presented flanking stimuli, but one used colored circle stimuli and the other used letter stimuli. Competition-related activation was identified by comparing Incongruent trials, in which the flanker stimuli indicated a different response than the central stimulus, to Neutral stimuli, in which the flanker stimuli indicated no response. A region within the right inferior frontal gyrus exhibited significantly more competition-related activation for the color stimuli, whereas regions within the middle frontal gyri of both hemispheres exhibited more competition-related activation for the letter stimuli. The border of the right middle frontal and inferior frontal gyri and the anterior cingulate cortex (ACC) were significantly activated by competition for both types of stimulus materials. Posterior foci demonstrated a similar pattern: left inferior parietal cortex showed greater competition-related activation for the letters, whereas right parietal cortex was significantly activated by competition for both materials. These findings indicate that the resolution of response competition invokes both material-dependent and material-independent processes.

  9. Effective Brain Connectivity in Children with Reading Difficulties during Phonological Processing

    ERIC Educational Resources Information Center

    Cao, Fan; Bitan, Tali; Booth, James R.

    2008-01-01

    Using Dynamic Causal Modeling (DCM) and functional magnetic resonance imaging (fMRI), we examined effective connectivity between three left hemisphere brain regions (inferior frontal gyrus, inferior parietal lobule, fusiform gyrus) and bilateral medial frontal gyrus in 12 children with reading difficulties (M age = 12.4, range: 8.11-14.10) and 12…

  10. Attenuating illusory binding with TMS of the right parietal cortex

    PubMed Central

    Esterman, Michael; Verstynen, Timothy; Robertson, Lynn C.

    2007-01-01

    A number of neuroimaging and neuropsychology studies have implicated various regions of parietal cortex as playing a critical role in the binding of color and form into conjunctions. The current study investigates the role of two such regions by examining how parietal transcranial magnetic stimulation (TMS) influences binding errors known as ‘illusory conjunctions.’ Participants made fewer binding errors after 1 Hz rTMS of the right intraparietal sulcus (IPS), while basic perception of features (colors and shape) was unaffected. No perceptual effects were found following left IPS stimulation, or stimulation of the right angular gyrus at the junction of the transverse occipital sulcus (IPS/TOS). These results support a role for the parietal cortex in feature binding but in ways that may require rethinking. PMID:17336097

  11. Meta-analysis: how does posterior parietal cortex contribute to reasoning?

    PubMed

    Wendelken, Carter

    2014-01-01

    Reasoning depends on the contribution of posterior parietal cortex (PPC). But PPC is involved in many basic operations-including spatial attention, mathematical cognition, working memory, long-term memory, and language-and the nature of its contribution to reasoning is unclear. Psychological theories of the processes underlying reasoning make divergent claims about the neural systems that are likely to be involved, and better understanding the specific contribution of PPC can help to inform these theories. We set out to address several competing hypotheses, concerning the role of PPC in reasoning: (1) reasoning involves application of formal logic and is dependent on language, with PPC activation for reasoning mainly reflective of linguistic processing; (2) reasoning involves probabilistic computation and is thus dependent on numerical processing mechanisms in PPC; and (3) reasoning is built upon the representation and processing of spatial relations, and PPC activation associated with reasoning reflects spatial processing. We conducted two separate meta-analyses. First, we pooled data from our own studies of reasoning in adults, and examined activation in PPC regions of interest (ROI). Second, we conducted an automated meta-analysis using Neurosynth, in which we examined overlap between activation maps associated with reasoning and maps associated with other key functions of PPC. In both analyses, we observed reasoning-related activation concentrated in the left Inferior Parietal Lobe (IPL). Reasoning maps demonstrated the greatest overlap with mathematical cognition. Maintenance, visuospatial, and phonological processing also demonstrated some overlap with reasoning, but a large portion of the reasoning map did not overlap with the map for any other function. This evidence suggests that the PPC's contribution to reasoning may be most closely related to its role in mathematical cognition, but that a core component of this contribution may be specific to reasoning.

  12. Importance of human right inferior frontoparietal network connected by inferior branch of superior longitudinal fasciculus tract in corporeal awareness of kinesthetic illusory movement.

    PubMed

    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.

  13. Parietal hemineglect and motor deficits in the monkey.

    PubMed

    Deuel, R K; Regan, D J

    1985-01-01

    To study the parietal hemineglect syndrome, we trained and operated nine Macaca fasicularis monkeys. Contralateral to the lesion they showed response abnormalities to visual and somatic sensory stimuli, and misreaching toward targets in visual space, abberant finger and wrist postures and lack of pincer grasp. The latter did not appear during performance of a preoperatively practised task, nor depend for severity upon lesion size, whereas sensory response abnormalities did. We conclude that abnormal motor patterns are separable from hemineglect in parietal animals, and are worst when the movement is directed to a visual target in extrapersonal space.

  14. [Inferior vestibular neuritis: diagnosis using VEMP].

    PubMed

    Walther, L E; Repik, I

    2012-02-01

    Vestibular evoked myogenic potentials (VEMP) are a new method to establish the functional status of the otolith organs. The sacculocollic reflex of the cervical VEMP to air conduction (AC) reflects predominantly saccular function due to saccular afferents to the inferior vestibular nerve. We describe a case of inferior vestibular neuritis as a rare differential diagnosis of vestibular neuritis. Clinical signs were a normal caloric response, unilaterally absent AC cVEMPs and bilaterally preserved ocular VEMPs (AC oVEMPs).

  15. Lobulated Enhancement Evaluation in the Follow-Up of Liver Metastases Treated by Stereotactic Body Radiation Therapy

    SciTech Connect

    Jarraya, Hajer; Borde, Paul; Mirabel, Xavier; Ernst, Olivier; Boulanger, Thomas; Lartigau, Eric; Ceugnart, Luc; Kramar, Andrew; Taieb, Sophie

    2015-06-01

    Objective: The Response Evaluation Criteria in Solid Tumors (RECIST) can have limitations when used to evaluate local treatments for cancer, especially for liver malignancies treated by stereotactic body radiation therapy (SBRT). The aim of this study was to validate the relationship between the occurrence of lobulated enhancement (LE) and local relapse and to evaluate the utility of this relationship for predicting local progression. Patients and Methods: Imaging data of 59 lesions in 46 patients, including 281 computed tomographic (CT) scans, were retrospectively and blindly reviewed by 3 radiologists. One radiologist measured the lesion size, for each CT and overall, to classify responses using RECIST threshold criteria. The second studied LE occurrence. A third radiologist was later included and studied LE occurrence to evaluate the interobserver consistency for LE evaluation. Results: The mean duration of follow-up was 13.6 months. LE was observed in 16 of 18 progressive lesions, occurring before size-based progression in 50% of cases, and the median delay of LE detection was 3.2 months. The sensitivity of LE to predict progression was 89%, and its specificity was 100%. The positive predictive value was 100%, the negative predictive value was 95.3%, and the overall accuracy was 97%. The probability of local progression-free survival at 12 months was significantly higher for lesions without LE compared with all lesions: 0.80 (CI 95%: 0.65-0.89) versus 0.69 (CI 95%: 0.54-0.80), respectively. The overall concordance rate between the 2 readers of LE was 97.9%. Conclusion: Response assessment of liver metastases treated by SBRT can be improved by including LE. This study demonstrates the diagnostic and predictive utility of LE for assessing local progression at a size still eligible for local salvage treatment.

  16. Extensive nuclear lobulation in the cells of a patient with acute myelomonocytic leukemia. The role of electron microscopy for establishment of a correct diagnosis.

    PubMed

    Djaldetti, M; Cohen, A; Gardyn, J; Bendayan, D

    1990-07-01

    Extensive nuclear convolution and lobulation was found in the peripheral blood cells of a patient with acute leukemia. While the morphology of the cells, such as observed with the light microscope, was compatible with the diagnosis of acute myeloid leukemia, the finding of Sezary-like cells with the electron microscope helped to establish the diagnosis of acute myelomonocytic leukemia. This report emphasizes the importance of the electron microscope for the correct diagnosis of leukemias.

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

    PubMed

    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.

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

    PubMed

    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.

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

    PubMed

    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.

  20. Alzheimer's disease with asymmetric parietal lobe atrophy: a case report.

    PubMed

    Kaida, K; Takeda, K; Nagata, N; Kamakura, K

    1998-09-18

    A 52-year-old, right-handed female presented with visuospatial dysfunction including left hemineglect, incomplete Balint's syndrome, and environmental agnosia, together with left-sided motor symptoms such as unskillful movement, dystonic postures, and myoclonus in the left hand, without significant dementia. Symptoms progressed to akinetic mutism prior to her death 10 years after onset of illness. Imaging studies such as MRI, SPECT, and PET studies showed severe, predominantly right-sided involvement of parietal and parieto-occipital areas. The motor signs might originate from the right parietal lesions such as area five or somatosensory area. Neuropathologic studies including immunocytochemistry showed tau-positive neurofibrillary tangles and abundant neuritic plaques with amyloid deposits, confirming the diagnosis of Alzheimer's disease. An analysis of serum apolipoprotein E revealed epsilon3/epsilon3 homozygosity. This case represents a variant of Alzheimer's disease conspicuous for progressive motor signs and visuospatial dysfunction with a striking laterality, reflecting asymmetric parietal involvement. Alzheimer's disease with asymmetric parietal atrophy is difficult to be clinically distinguished from corticobasal degeneration characterized by progressive unilateral motor signs and focal cortical signs.

  1. Histamine-stimulated phosphorylation of gastric parietal cell proteins

    SciTech Connect

    Chew, C.S.; Brown, M.R.

    1987-05-01

    Parietal cells from rabbit gastric mucosa respond to histamine with increased HCl secretion. Histamine also increases cAMP and activates cAMP-dependent protein kinase(s) in these cells. cAMP analogues and forskolin appear to mimic these effects. More recently histamine and forskolin but not cAMP-stimulated increases in (Ca/sup 2 +/)/sub i/ have been detected in parietal cells enriched to 98 +/- 2% (n=10) purity using a combined Nycodenz density gradient/centrifugal elutriation technique. In the present experiments parietal cells were loaded with /sup 32/P to label ATP pools then stimulated with histamine or chlorophenylthio-cAMP plus the H/sub 2/ receptor antagonist, cimetidine. Total cell extracts were separated via 2D-gel electrophoresis and analyzed with a Masscomp computer and PDQuest software. Results indicate that histamine stimulates phosphorylation of at least two proteins with molecular weights 49 and 33 kDa and respective pI's of 6.4 and 6.0. Changes in phosphorylation are detected within 1 min of stimulation and remain elevated for at least 15 min. No change in specific activity of samples was detected during this time. A third protein also showed increased phosphorylation but the response appeared more transient. They conclude that histamine increases phosphorylation of several parietal cell proteins via a cAMP-dependent mechanism. The relationship between changes in phosphorylation and onset of HCl secretion remains to be determined.

  2. Impairments in Tactile Search Following Superior Parietal Damage

    ERIC Educational Resources Information Center

    Skakoon-Sparling, Shayna P.; Vasquez, Brandon P.; Hano, Kate; Danckert, James

    2011-01-01

    The superior parietal cortex is critical for the control of visually guided actions. Research suggests that visual stimuli relevant to actions are preferentially processed when they are in peripersonal space. One recent study demonstrated that visually guided movements towards the body were more impaired in a patient with damage to superior…

  3. Topographic Maps of Visual Spatial Attention in Human Parietal Cortex

    PubMed Central

    Silver, Michael A.; Ress, David; Heeger, David J.

    2008-01-01

    Functional magnetic resonance imaging (fMRI) was used to measure activity in human parietal cortex during performance of a visual detection task in which the focus of attention systematically traversed the visual field. Critically, the stimuli were identical on all trials (except for slight contrast changes in a fully randomized selection of the target locations) whereas only the cued location varied. Traveling waves of activity were observed in posterior parietal cortex consistent with shifts in covert attention in the absence of eye movements. The temporal phase of the fMRI signal in each voxel indicated the corresponding visual field location. Visualization of the distribution of temporal phases on a flattened representation of parietal cortex revealed at least two distinct topographically organized cortical areas within the intraparietal sulcus (IPS), each representing the contralateral visual field. Two cortical areas were proposed based on this topographic organization, which we refer to as IPS1 and IPS2 to indicate their locations within the IPS. This nomenclature is neutral with respect to possible homologies with well-established cortical areas in the monkey brain. The two proposed cortical areas exhibited relatively little response to passive visual stimulation in comparison with early visual areas. These results provide evidence for multiple topographic maps in human parietal cortex. PMID:15817643

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

    PubMed

    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.

  5. Subcutaneous Construction of Engineered Adipose Tissue with Fat Lobule-Like Structure Using Injectable Poly-Benzyl-L-Glutamate Microspheres Loaded with Adipose-Derived Stem Cells.

    PubMed

    Sun, Wentao; Fang, Jianjun; Yong, Qi; Li, Sufang; Xie, Qingping; Yin, Jingbo; Cui, Lei

    2015-01-01

    Porous microcarriers were fabricated from synthesized poly(γ-benzyl-L-glutamate) (PBLG) polymer to engineer adipose tissue with lobule-like structure via the injectable approach. The adipogenic differentiation of human adipose-derived stem cells (hASCs) seeded on porous PBLG microcarriers was determined by adipogenic gene expression and glycerol-3-phosphate dehydrogenase enzyme activity. In vitro adipogenic cultivation was performed for 7 days, and induced hASC/PBLG complex (Adi-ASC/PBLG group) was subcutaneously injected into nude mice. Injections of PBLG microcarriers alone (PBLG group) and non-induced hASC/PBLG complex (ASC/PBLG group) served as controls. Newly formed tissues were harvested after 4 and 8 weeks. Generation of subcutaneous adipose tissue with typical lobule-like structure separated by fibrous septa was observed upon injection of adipogenic-induced hASC/microsphere complex. Adipogenesis significantly increased in the Adi-ASC/PBLG group compared with the control groups. The angiogenesis in the engineered adipose tissue was comparable to that in normal tissue as determined by capillary density and luminal diameter. Cell tracking assay demonstrated that labeled hASCs remained detectable in the neo-generated tissues 8 weeks post-injection using green fluorescence protein-labeled hASCs. These results indicate that adipose tissue with typical lobule-like structure could be engineered using injectable porous PBLG microspheres loaded with adipogenic-induced hASCs.

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

    PubMed

    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.

  7. Decreased resting state metabolic activity in frontopolar and parietal brain regions is associated with suicide plans in depressed individuals.

    PubMed

    van Heeringen, Kees; Wu, Guo-Rong; Vervaet, Myriam; Vanderhasselt, Marie-Anne; Baeken, Chris

    2017-01-01

    Suicide plans are a major risk factor for suicide, which is a devastating outcome of depression. While structural and functional brain changes have been demonstrated in relation to suicidal thoughts and behaviour, brain mechanisms underlying suicide plans have not yet been studied. Here, we studied changes in regional cerebral metabolic activity in association with suicide plans in depressed individuals. Using (18)FDG-PET, a comparative study of regional cerebral glucose metabolism (rCMRglu) was carried out in depressed individuals with suicidal thoughts and suicide plans, depressed individuals with only suicidal thoughts, depressed individuals without suicide thoughts and plans, and healthy controls. When compared to the other groups, depressed individuals with suicide plans showed relative hypometabolism in the right middle frontal gyrus and the right inferior parietal lobe (Brodmann areas 10 and 39). Suicide plans in depressed individuals appear to be associated with reduced activity in brain areas that are involved in decision-making and choice, more particularly in exploratory behaviour.

  8. Parietal structure and function explain human variation in working memory biases of visual attention.

    PubMed

    Soto, David; Rotshtein, Pia; Kanai, Ryota

    2014-04-01

    Recent research indicates that human attention appears inadvertently biased by items that match the contents of working memory (WM). WM-biases can lead to attentional costs when the memory content matches goal-irrelevant items and to attentional benefits when it matches the sought target. Here we used functional and structural MRI data to determine the neural basis of human variation in WM biases. We asked whether human variation in WM-benefits and WM-costs merely reflects the process of attentional capture by the contents of WM or whether variation in WM biases may be associated with distinct forms of cognitive control over internal WM signals based on selection goals. Human ability to use WM contents to facilitate selection was positively correlated with gray matter volume in the left superior posterior parietal cortex (PPC), while the ability to overcome interference by WM-matching distracters was associated with the left inferior PPC in the anterior IPS. Functional activity in the left PPC, measured by functional MRI, also predicted the magnitude of WM-costs on selection. Both structure and function of left PPC mediate the expression of WM biases in human visual attention.

  9. Lateralization Technique and Inferior Alveolar Nerve Transposition

    PubMed Central

    Sanches, Marco Antonio; Ramalho, Gabriel Cardoso; Manzi, Marcello Roberto

    2016-01-01

    Bone resorption of the posterior mandible can result in diminished bone edge and, therefore, the installation of implants in these regions becomes a challenge, especially in the presence of the mandibular canal and its contents, the inferior alveolar nerve. Several treatment alternatives are suggested: the use of short implants, guided bone regeneration, appositional bone grafting, distraction osteogenesis, inclined implants tangential to the mandibular canal, and the lateralization of the inferior alveolar nerve. The aim was to elucidate the success rate of implants in the lateralization technique and in inferior alveolar nerve transposition and to determine the most effective sensory test. We conclude that the success rate is linked to the possibility of installing implants with long bicortical anchor which favors primary stability and biomechanics. PMID:27433360

  10. Extracellular calcium and cholinergic stimulation of isolated canine parietal cells.

    PubMed Central

    Soll, A H

    1981-01-01

    The role of calcium gating in cholinergic stimulation of the function of parietal cells was studied using cells isolated from canine fundic mucosa by treatment with collagenase and EDTA and enriched by velocity separation in an elutriator rotor. Monitoring the accumulation of [14C[ aminopyrine as an index of parietal cell response, stimulation by carbachol, but not by histamine, was highly dependent upon the concentration of extracellular calcium. Incubation of parietal cells in 0-.1 mM calcium, rather than the usual 1.8 mM concentration, reduced the response to 100 microM carbachol by 92 +/- 2%, whereas histamine stimulation was impaired by 28 +/- 5%. A similar reduction in extracellular calcium suppressed the response to gastrin (100 nM) by 67 +/- 7%. The impairment of cholinergic stimulation found at low extracellular calcium concentrations was rapidly reversed with the readdition of calcium. Lanthanum, which blocks calcium movement across membranes, caused a similar pattern of effects on secretagogue stimulation of aminopyrine accumulation, with 100 microM lanthanum suppressing carbachol stimulation by 83 +/- 2%. This concentration of lanthanum suppressed gastrin stimulation by 40 +/- 7% and histamine stimulation by only 12 +/- 9%. Carbachol, but not histamine nor gastrin, stimulated 45Ca++ uptake. The magnitude of carbachol-stimulated calcium uptake correlated with the parietal cell content of the fractions examined (r = 0.88), and was dose responsive over carbachol concentrations from 1 microM to 1 mM. Atropine (100 nM) caused surmountable inhibition, and these effects of carbachol and atropine on calcium uptake correlated with their effects on oxygen consumption (r = 0.93) and [14C]-aminopyrine accumulation (r = 0.90). Cells preloaded with 45Ca++ lost cellular calcium in a time-dependent fashion; however, this rate of egress was not accelerated by treatment with histamine, gastrin, or carbachol, thus failing to implicate mobilization of intracellular calcium

  11. Inferior Vena Cava Filters for Recurrent Thrombosis

    PubMed Central

    Patel, Salil H.; Patel, Rima

    2007-01-01

    Inferior vena cava filters are often used as alternatives to anticoagulant therapy for the prevention of pulmonary embolism. Many of the clinical data that support the use of these devices stem from relatively limited retrospective studies. The dual purpose of this review is to examine the incidence of thrombotic complications associated with inferior vena cava filters and to discuss the role of anticoagulant therapy concurrent with filter placement. Device-associated morbidity and overall efficacy can be considered only in the context of rates of vena cava thrombosis, insertion-site thrombosis, recurrent deep venous thrombosis, and recurrent pulmonary embolism. PMID:17622366

  12. Left inferior frontal cortex and syntax: function, structure and behaviour in patients with left hemisphere damage.

    PubMed

    Tyler, Lorraine K; Marslen-Wilson, William D; Randall, Billi; Wright, Paul; Devereux, Barry J; Zhuang, Jie; Papoutsi, Marina; Stamatakis, Emmanuel A

    2011-02-01

    For the past 150 years, neurobiological models of language have debated the role of key brain regions in language function. One consistently debated set of issues concern the role of the left inferior frontal gyrus in syntactic processing. Here we combine measures of functional activity, grey matter integrity and performance in patients with left hemisphere damage and healthy participants to ask whether the left inferior frontal gyrus is essential for syntactic processing. In a functional neuroimaging study, participants listened to spoken sentences that either contained a syntactically ambiguous or matched unambiguous phrase. Behavioural data on three tests of syntactic processing were subsequently collected. In controls, syntactic processing co-activated left hemisphere Brodmann areas 45/47 and posterior middle temporal gyrus. Activity in a left parietal cluster was sensitive to working memory demands in both patients and controls. Exploiting the variability in lesion location and performance in the patients, voxel-based correlational analyses showed that tissue integrity and neural activity-primarily in left Brodmann area 45 and posterior middle temporal gyrus-were correlated with preserved syntactic performance, but unlike the controls, patients were insensitive to syntactic preferences, reflecting their syntactic deficit. These results argue for the essential contribution of the left inferior frontal gyrus in syntactic analysis and highlight the functional relationship between left Brodmann area 45 and the left posterior middle temporal gyrus, suggesting that when this relationship breaks down, through damage to either region or to the connections between them, syntactic processing is impaired. On this view, the left inferior frontal gyrus may not itself be specialized for syntactic processing, but plays an essential role in the neural network that carries out syntactic computations.

  13. Left inferior frontal cortex and syntax: function, structure and behaviour in patients with left hemisphere damage

    PubMed Central

    Marslen-Wilson, William D.; Randall, Billi; Wright, Paul; Devereux, Barry J.; Zhuang, Jie; Papoutsi, Marina; Stamatakis, Emmanuel A.

    2011-01-01

    For the past 150 years, neurobiological models of language have debated the role of key brain regions in language function. One consistently debated set of issues concern the role of the left inferior frontal gyrus in syntactic processing. Here we combine measures of functional activity, grey matter integrity and performance in patients with left hemisphere damage and healthy participants to ask whether the left inferior frontal gyrus is essential for syntactic processing. In a functional neuroimaging study, participants listened to spoken sentences that either contained a syntactically ambiguous or matched unambiguous phrase. Behavioural data on three tests of syntactic processing were subsequently collected. In controls, syntactic processing co-activated left hemisphere Brodmann areas 45/47 and posterior middle temporal gyrus. Activity in a left parietal cluster was sensitive to working memory demands in both patients and controls. Exploiting the variability in lesion location and performance in the patients, voxel-based correlational analyses showed that tissue integrity and neural activity—primarily in left Brodmann area 45 and posterior middle temporal gyrus—were correlated with preserved syntactic performance, but unlike the controls, patients were insensitive to syntactic preferences, reflecting their syntactic deficit. These results argue for the essential contribution of the left inferior frontal gyrus in syntactic analysis and highlight the functional relationship between left Brodmann area 45 and the left posterior middle temporal gyrus, suggesting that when this relationship breaks down, through damage to either region or to the connections between them, syntactic processing is impaired. On this view, the left inferior frontal gyrus may not itself be specialized for syntactic processing, but plays an essential role in the neural network that carries out syntactic computations. PMID:21278407

  14. Overlapping Parietal Activity in Memory and Perception: Evidence for the Attention to Memory Model

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  16. Optic ataxia: from Balint's syndrome to the parietal reach region.

    PubMed

    Andersen, Richard A; Andersen, Kristen N; Hwang, Eun Jung; Hauschild, Markus

    2014-03-05

    Optic ataxia is a high-order deficit in reaching to visual goals that occurs with posterior parietal cortex (PPC) lesions. It is a component of Balint's syndrome that also includes attentional and gaze disorders. Aspects of optic ataxia are misreaching in the contralesional visual field, difficulty preshaping the hand for grasping, and an inability to correct reaches online. Recent research in nonhuman primates (NHPs) suggests that many aspects of Balint's syndrome and optic ataxia are a result of damage to specific functional modules for reaching, saccades, grasp, attention, and state estimation. The deficits from large lesions in humans are probably composite effects from damage to combinations of these functional modules. Interactions between these modules, either within posterior parietal cortex or downstream within frontal cortex, may account for more complex behaviors such as hand-eye coordination and reach-to-grasp.

  17. [Right parietal lesions, spatial neglect and egocentric reference].

    PubMed

    Bartolomeo, P; Chokron, S; Degos, J D

    2000-02-01

    Using a proprioceptive "straight-ahead" pointing task, we determined the position of the subjective sagittal middle in thirty unselected patients with unilateral vascular lesions in the right hemisphere and twenty-two normal controls. Patients with extensive right parietal damage (n = 16) showed an ipsilesional (rightward) deviation of their egocentric reference, whereas patients with lesions that substantially spared the right parietal lobe (n = 14) showed a contralesional (leftward) deviation. No significant correlation emerged between the position of the egocentric reference and the performance on a neglect battery. These results can help explain some dissociations between left neglect signs and ipsilesional deviation of the egocentric reference, and raise some questions about the links among lesion location, neglect signs and egocentric frame of reference.

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

    PubMed

    Chaouki, Sana; Boujraf, Saïd; Atmani, Samir; Elarqam, Larbi; Messouak, Wafae

    2013-01-01

    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.

  19. Neuronal oscillations form parietal/frontal networks during contour integration.

    PubMed

    Castellano, Marta; Plöchl, Michael; Vicente, Raul; Pipa, Gordon

    2014-01-01

    The ability to integrate visual features into a global coherent percept that can be further categorized and manipulated are fundamental abilities of the neural system. While the processing of visual information involves activation of early visual cortices, the recruitment of parietal and frontal cortices has been shown to be crucial for perceptual processes. Yet is it not clear how both cortical and long-range oscillatory activity leads to the integration of visual features into a coherent percept. Here, we will investigate perceptual grouping through the analysis of a contour categorization task, where the local elements that form contour must be linked into a coherent structure, which is then further processed and manipulated to perform the categorization task. The contour formation in our visual stimulus is a dynamic process where, for the first time, visual perception of contours is disentangled from the onset of visual stimulation or from motor preparation, cognitive processes that until now have been behaviorally attached to perceptual processes. Our main finding is that, while local and long-range synchronization at several frequencies seem to be an ongoing phenomena, categorization of a contour could only be predicted through local oscillatory activity within parietal/frontal sources, which in turn, would synchronize at gamma (>30 Hz) frequency. Simultaneously, fronto-parietal beta (13-30 Hz) phase locking forms a network spanning across neural sources that are not category specific. Both long range networks, i.e., the gamma network that is category specific, and the beta network that is not category specific, are functionally distinct but spatially overlapping. Altogether, we show that a critical mechanism underlying contour categorization involves oscillatory activity within parietal/frontal cortices, as well as its synchronization across distal cortical sites.

  20. Gestalt perception is associated with reduced parietal beta oscillations.

    PubMed

    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.

  1. Bottom-up Visual Integration in the Medial Parietal Lobe.

    PubMed

    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.

  2. Spatio-Temporal Updating in the Left Posterior Parietal Cortex

    PubMed Central

    Wada, Makoto; Takano, Kouji; Ikegami, Shiro; Ora, Hiroki; Spence, Charles; Kansaku, Kenji

    2012-01-01

    Adopting an unusual posture can sometimes give rise to paradoxical experiences. For example, the subjective ordering of successive unseen tactile stimuli delivered to the two arms can be affected when people cross them. A growing body of evidence now highlights the role played by the parietal cortex in spatio-temporal information processing when sensory stimuli are delivered to the body or when actions are executed; however, little is known about the neural basis of such paradoxical feelings resulting from such unusual limb positions. Here, we demonstrate increased fMRI activation in the left posterior parietal cortex when human participants adopted a crossed hands posture with their eyes closed. Furthermore, by assessing tactile temporal order judgments (TOJs) in the same individuals, we observed a positive association between activity in this area and the degree of reversal in TOJs resulting from crossing arms. The strongest positive association was observed in the left intraparietal sulcus. This result implies that the left posterior parietal cortex may be critically involved in monitoring limb position and in spatio-temporal binding when serial events are delivered to the limbs. PMID:22768126

  3. Early recurrence and ongoing parietal driving during elementary visual processing

    PubMed Central

    Plomp, Gijs; Hervais-Adelman, Alexis; Astolfi, Laura; Michel, Christoph M.

    2015-01-01

    Visual stimuli quickly activate a broad network of brain areas that often show reciprocal structural connections between them. Activity at short latencies (<100 ms) is thought to represent a feed-forward activation of widespread cortical areas, but fast activation combined with reciprocal connectivity between areas in principle allows for two-way, recurrent interactions to occur at short latencies after stimulus onset. Here we combined EEG source-imaging and Granger-causal modeling with high temporal resolution to investigate whether recurrent and top-down interactions between visual and attentional brain areas can be identified and distinguished at short latencies in humans. We investigated the directed interactions between widespread occipital, parietal and frontal areas that we localized within participants using fMRI. The connectivity results showed two-way interactions between area MT and V1 already at short latencies. In addition, the results suggested a large role for lateral parietal cortex in coordinating visual activity that may be understood as an ongoing top-down allocation of attentional resources. Our results support the notion that indirect pathways allow early, evoked driving from MT to V1 to highlight spatial locations of motion transients, while influence from parietal areas is continuously exerted around stimulus onset, presumably reflecting task-related attentional processes. PMID:26692466

  4. A Parcellation Scheme for Human Left Lateral Parietal Cortex

    PubMed Central

    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.

    2010-01-01

    SUMMARY 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”) vs. unstudied (“new”). These studies have suggested functional divisions within LLPC that may provide distinct contributions towards recognition memory judgments. Here, we define regions within LLPC by developing a novel parcellation scheme that integrates data from resting state functional connectivity MRI (rsfcMRI) and functional MRI (fMRI). This combined approach results in a six-fold parcellation of LLPC based on the presence (or absence) of memory retrieval-related activity, dissociations in the profile of task-evoked timecourses, and membership in large-scale brain networks. This parcellation should serve as a roadmap for future investigations aimed at understanding LLPC function. PMID:20624599

  5. Efferent pathways modulate hyperactivity in inferior colliculus.

    PubMed

    Mulders, Wilhelmina Henrica A M; Seluakumaran, Kumar; Robertson, Donald

    2010-07-14

    Animal models have demonstrated that mild hearing loss caused by acoustic trauma results in spontaneous hyperactivity in the central auditory pathways. This hyperactivity has been hypothesized to be involved in the generation of tinnitus, a phantom auditory sensation. We have recently shown that such hyperactivity, recorded in the inferior colliculus, is still dependent on cochlear neural output for some time after recovery (up to 6 weeks). We have now studied the capacity of an intrinsic efferent system, i.e., the olivocochlear system, to alter hyperactivity. This system is known to modulate cochlear neural output. Anesthetized guinea pigs were exposed to a loud sound and after 2 or 3 weeks of recovery, single-neuron recordings in inferior colliculus were made to confirm hyperactivity. Olivocochlear axons were electrically stimulated and effects on cochlear neural output and on highly spontaneous neurons in inferior colliculus were assessed. Olivocochlear stimulation suppressed spontaneous hyperactivity in the inferior colliculus. This result is in agreement with our earlier finding that hyperactivity can be modulated by altering cochlear neural output. Interestingly, the central suppression was generally much larger and longer lasting than reported previously for primary afferents. Blockade of the intracochlear effects of olivocochlear system activation eliminated some but not all of the effects observed on spontaneous activity, suggesting also a central component to the effects of stimulation. More research is needed to investigate whether these central effects of olivocochlear efferent stimulation are due to central intrinsic circuitry or to coactivation of central efferent collaterals to the cochlear nucleus.

  6. The Role of the Frontal and Parietal Cortex in Proactive and Reactive Inhibitory Control: A Transcranial Direct Current Stimulation Study.

    PubMed

    Cai, Ying; Li, Siyao; Liu, Jing; Li, Dawei; Feng, Zifang; Wang, Qiang; Chen, Chuansheng; Xue, Gui

    2016-01-01

    Mounting evidence suggests that response inhibition involves both proactive and reactive inhibitory control, yet its underlying neural mechanisms remain elusive. In particular, the roles of the right inferior frontal gyrus (IFG) and inferior parietal lobe (IPL) in proactive and reactive inhibitory control are still under debate. This study aimed at examining the causal role of the right IFG and IPL in proactive and reactive inhibitory control, using transcranial direct current stimulation (tDCS) and the stop signal task. Twenty-two participants completed three sessions of the stop signal task, under anodal tDCS in the right IFG, the right IPL, or the primary visual cortex (VC; 1.5 mA for 15 min), respectively. The VC stimulation served as the active control condition. The tDCS effect for each condition was calculated as the difference between pre- and post-tDCS performance. Proactive control was indexed by the RT increase for go trials (or preparatory cost), and reactive control by the stop signal RT. Compared to the VC stimulation, anodal stimulation of the right IFG, but not that of the IPL, facilitated both proactive and reactive control. However, the facilitation of reactive control was not mediated by the facilitation of proactive control. Furthermore, tDCS did not affect the intraindividual variability in go RT. These results suggest a causal role of the right IFG, but not the right IPL, in both reactive and proactive inhibitory control.

  7. Spatio-Temporal Dynamics of Human Intention Understanding in Temporo-Parietal Cortex: A Combined EEG/fMRI Repetition Suppression Paradigm

    PubMed Central

    Ortigue, Stephanie; Thompson, James C.; Parasuraman, Raja; Grafton, Scott T.

    2009-01-01

    Inferring the intentions of other people from their actions recruits an inferior fronto-parietal action observation network as well as a putative social network that includes the posterior superior temporal sulcus (STS). However, the functional dynamics within and among these networks remains unclear. Here we used functional magnetic resonance imaging (fMRI) and high-density electroencephalogram (EEG), with a repetition suppression design, to assess the spatio-temporal dynamics of decoding intentions. Suppression of fMRI activity to the repetition of the same intention was observed in inferior frontal lobe, anterior intraparietal sulcus (aIPS), and right STS. EEG global field power was reduced with repeated intentions at an early (starting at 60 ms) and a later (∼330 ms) period after the onset of a hand-on-object encounter. Source localization during these two intervals involved right STS and aIPS regions highly consistent with RS effects observed with fMRI. These results reveal the dynamic involvement of temporal and parietal networks at multiple stages during the intention decoding and without a strict segregation of intention decoding between these networks. PMID:19750227

  8. On the Role of the Inferior Intraparietal Sulcus in Visual Working Memory for Lateralized Single-feature Objects.

    PubMed

    Brigadoi, Sabrina; Cutini, Simone; Meconi, Federica; Castellaro, Marco; Sessa, Paola; Marangon, Mattia; Bertoldo, Alessandra; Jolicœur, Pierre; Dell'Acqua, Roberto

    2017-02-01

    A consolidated practice in cognitive neuroscience is to explore the properties of human visual working memory through the analysis of electromagnetic signals using cued change detection tasks. Under these conditions, EEG/MEG activity increments in the posterior parietal cortex scaling with the number of memoranda are often reported in the hemisphere contralateral to the objects' position in the memory array. This highly replicable finding clashes with several reported failures to observe compatible hemodynamic activity modulations using fMRI or fNIRS in comparable tasks. Here, we reconcile this apparent discrepancy by acquiring fMRI data on healthy participants and employing a cluster analysis to group voxels in the posterior parietal cortex based on their functional response. The analysis identified two distinct subpopulations of voxels in the intraparietal sulcus (IPS) showing a consistent functional response among participants. One subpopulation, located in the superior IPS, showed a bilateral response to the number of objects coded in visual working memory. A different subpopulation, located in the inferior IPS, showed an increased unilateral response when the objects were displayed contralaterally. The results suggest that a cluster of neurons in the inferior IPS is a candidate source of electromagnetic contralateral responses to working memory load in cued change detection tasks.

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

    PubMed

    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

  10. Leiomyosarcoma arising from the inferior mesenteric vein

    PubMed Central

    Clemente, Gennaro; Sarno, Gerardo; Barbaro, Brunella; Nuzzo, Gennaro

    2009-01-01

    Leyomiosarcomas arising from the portal/mesenteric venous system are very rare tumours, and only a few cases have been reported in the global literature. As the other leyomiosarcomas of vascular origin, they are associated with a poor prognosis. The present report describes the case of a 66-year-old woman with a leyomiosarcoma of the inferior mesenteric vein, unexpectedly found during a CT scan performed for another indication. A brief review of the literature is also given. The patient underwent radical surgical excision and enjoys a good health, without radiological signs of recurrence, 24 months after surgery. In this case, an early incidental diagnosis determined an early treatment and, probably, a favourable prognosis. This is the second case of leyomiosarcoma of the inferior mesenteric vein reported in the literature. PMID:21686492

  11. Developmental Phases of the Seminal Vesicle related to the Spermatogenic Stages in the Testicular Lobules of Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae)

    PubMed Central

    Kim, Sung Han

    2016-01-01

    Cytological changes of the epithelial cells according to the developmenatal phases of the seminal vesicle related to the spermatogenic stages in the testicular lobules during spermagenesis in male Neptunea (Barbitonia) cumingii (Gastropoda: Buccinidae) were investigated monthly by electron microscopical and histological observations. N. (B) cumingii is dioecious, and an internal fertilization species. The male genital organ is located near the tentacles. The spermatozoon is approximatley 50 μm in length. The axoneme of the tail flagellum consists of nine pairs of microtubles at the periphery and one pair at the center. The process of germ cell development during spermatogenesis can be divided into five succesive stages: (1) spermatogonia, (2) primary spermatocytes, (3) secondary spermatocytes, (4) spermatids, and (5) spermatozoa. A considerable amount of spermatozoa make their appearance in the testicular lobules (or acini) and some of them are tranported from the testis towards the seminal vesicles until late July. In this study, the developmental phases of the epithelial cells of the seminal vesicles of N. (B.) cumingii could be classified into four phases: (1) S-I phase (resting), (2) S-Ⅱphase (early accumulating), (3) S-Ⅲ phase (accumulating), and (4) S-IV phase (spent). However, in case of N. (B.) arthritica cumingii, the developmental phases of the seminal vesicle were devided into three phases: (1) resting, (2) accumulating and (3) spent. Granular bodies in the inner layer of the seminal vesicles are involved in resorption of digestion of residual spermatozoa. PMID:27796006

  12. Ectopic overexpression of engrailed-2 in cerebellar Purkinje cells causes restricted cell loss and retarded external germinal layer development at lobule junctions.

    PubMed

    Baader, S L; Sanlioglu, S; Berrebi, A S; Parker-Thornburg, J; Oberdick, J

    1998-03-01

    Members of the En and Wnt gene families seem to play a key role in the early specification of the brain territory that gives rise to the cerebellum, the midhindbrain junction. To analyze the possible continuous role of the En and Wnt signaling pathway in later cerebellar patterning and function, we expressed En-2 ectopically in Purkinje cells during late embryonic and postnatal cerebellar development. As a result of this expression, the cerebellum is greatly reduced in size, and Purkinje cell numbers throughout the cerebellum are reduced by more than one-third relative to normal animals. Detailed analysis of both adult and developing cerebella reveals a pattern of selectivity to the loss of Purkinje cells and other cerebellar neurons. This is observed as a general loss of prominence of cerebellar fissures that is highlighted by a total loss of sublobular fissures. In contrast, mediolateral patterning is generally only subtly affected. That En-2 overexpression selectively affects Purkinje cells in the transition zone between lobules is evidenced by direct observation of selective Purkinje cell loss in certain fissures and by the observation that growth and migration of the external germinal layer (EGL) is selectively retarded in the deep fissures during early postnatal development. Thus, in addition to demonstrating the critical role of Purkinje cells in the generation and migration of granule cells, the heterogeneous distribution of cellular effects induced by ectopic En expression suggests a relatively late morphogenetic role for this and other segment polarity proteins, mainly oriented at lobule junctions.

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

    PubMed Central

    KURŞUN, Oğuzhan; KARATAŞ, Hülya; DERİCİOĞLU, Neşe; SAYGI, Serap

    2016-01-01

    Introduction 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. Methods 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. Results 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. Conclusion 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. PMID:28373797

  14. Leiomyosarcoma of the Inferior Vena Cava

    PubMed Central

    Sadri, Ben Abid; Amine, Attaoui Mohamed; Zeineb, Mzoughi; Nizar, Miloudi; Lassad, Gharbi; Khalfallah, Mohamed Tahar

    2013-01-01

    Vascular leiomyosarcoma (LMS) are unique. The inferior vena cava (IVC) is the most affected organ (about 38% cases). We report the observation of a 50-year old woman who consulted for right upper quadrant pain. Imaging studies revealed a retroperitoneal mass that mimic a LMS of the IVC. The patient was operated. A resection of the IVC along with the tumor was performed without reconstruction. The management of LMS is surgical and depends upon the location and tumor characteristics. PMID:24765501

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

    PubMed

    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. Environmental reduplication associated with right frontal and parietal lobe injury.

    PubMed

    Ruff, R L; Volpe, B T

    1981-05-01

    Four patients with environmental reduplication, a specific form of spatial disorientation and confabulation are described. The patients maintained that their hospital rooms were located in their homes. Each patients had evidence of right frontal or right parietal injury based upon computed tomography, neurosurgery, and neuropsychological testing. The factors associated with environmental reduplication were: impaired spatial perception and visual memory, inability of the patients to recognise the inconsistency between their believed location and their actual location, confusion soon after admission to hospital, and a strong desire to be at home.

  17. Posterior Parietal Cortex: An Interface between Attention and Learning?

    PubMed Central

    Bucci, David J.

    2009-01-01

    The posterior parietal cortex (PPC) of rats has most recently been defined based on patterns of thalamic and cortical connectivity. The anatomical characteristics of this area suggest that it may be homologous to the PPC of primates and contribute to similar functions. This review summarizes evidence for and against a role for the rat PPC in attention and working memory and evaluates how the function of the rat PPC compares to that of primates on these dimensions. Theories of how the rat PPC contributes to behavior are presented, including the notion that PPC may serve as an interface between attention and learning. Finally, several avenues for future research are considered. PMID:18675370

  18. Neural activity in the parietal eye of a lizard.

    PubMed

    MILLER, W H; WOLBARSHT, M L

    1962-01-26

    Electrical signs of activity in response to illumination of the parietal eye of the American chameleon, Anolis carolinensis, have been investigated. The responses were of two types. Under conditions of direct-coupled amplification, with glass pipette electrodes recording extracellularly from the retinal surface, the response consisted of an increase in negativity maintained throughout prolonged illumination. With capacitance-coupled amplification and metal electrodes, brisk mass discharges of nerve impulses were detected at the onset and cessation of illumination. During illumination a less vigorous maintained discharge was observed.

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

    PubMed Central

    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

  20. Non-inferiority trials: are they inferior? A systematic review of reporting in major medical journals

    PubMed Central

    Morris, Tim P; Fielding, Katherine; Carpenter, James R; Phillips, Patrick P J

    2016-01-01

    Objective To assess the adequacy of reporting of non-inferiority trials alongside the consistency and utility of current recommended analyses and guidelines. Design Review of randomised clinical trials that used a non-inferiority design published between January 2010 and May 2015 in medical journals that had an impact factor >10 (JAMA Internal Medicine, Archives Internal Medicine, PLOS Medicine, Annals of Internal Medicine, BMJ, JAMA, Lancet and New England Journal of Medicine). Data sources Ovid (MEDLINE). Methods We searched for non-inferiority trials and assessed the following: choice of non-inferiority margin and justification of margin; power and significance level for sample size; patient population used and how this was defined; any missing data methods used and assumptions declared and any sensitivity analyses used. Results A total of 168 trial publications were included. Most trials concluded non-inferiority (132; 79%). The non-inferiority margin was reported for 98% (164), but less than half reported any justification for the margin (77; 46%). While most chose two different analyses (91; 54%) the most common being intention-to-treat (ITT) or modified ITT and per-protocol, a large number of articles only chose to conduct and report one analysis (65; 39%), most commonly the ITT analysis. There was lack of clarity or inconsistency between the type I error rate and corresponding CIs for 73 (43%) articles. Missing data were rarely considered with (99; 59%) not declaring whether imputation techniques were used. Conclusions Reporting and conduct of non-inferiority trials is inconsistent and does not follow the recommendations in available statistical guidelines, which are not wholly consistent themselves. Authors should clearly describe the methods used and provide clear descriptions of and justifications for their design and primary analysis. Failure to do this risks misleading conclusions being drawn, with consequent effects on clinical practice. PMID:27855102

  1. Mirror agnosia and mirror ataxia constitute different parietal lobe disorders.

    PubMed

    Binkofski, F; Buccino, G; Dohle, C; Seitz, R J; Freund, H J

    1999-07-01

    We describe two new clinical syndromes, mirror agnosia and mirror ataxia, both characterized by the deficit of reaching for an object through a mirror in association with a lesion of either parietal lobe. Clinical investigation of 13 patients demonstrated that the impairments affected both sides of the body. In mirror agnosia, the patients always reached toward the virtual object in the mirror and they were not capable of changing their behavior even after presentation of the position of the object in real visual space. In mirror ataxia (resembling optic ataxia) although some patients initially tended to reach for the virtual object in the mirror, they soon learned to guide their arms toward the real object, all of them producing many directional errors. Both patient groups performed poorly on mental rotation, but only the patients with mirror agnosia were impaired in line orientation. Only 1 of the patients suffered from neglect and 3 from apraxia. Magnetic resonance imaging showed that in mirror agnosia the common zone of lesion overlap was scattered around the posterior angular gyrus/superior temporal gyrus and in mirror ataxia around the postcentral sulcus. We propose that both these clinical syndromes may represent different types of dissociation of retinotopic space and body scheme, or likewise, of allocentric and egocentric space normally adjusted in the parietal lobe.

  2. Parietal cortex mediates conscious perception of illusory gestalt.

    PubMed

    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.

  3. Frontal monitoring and parietal evidence: mechanisms of error correction

    PubMed Central

    Cebrian, Ana Navarro; Knight, Robert T.; Kayser, Andrew S.

    2016-01-01

    When we respond to a stimulus, our decisions are based not only on external stimuli but also on our ongoing performance. If the response deviates from our goals, monitoring and decision-making brain areas interact so that future behavior may change. By taking advantage of natural variation in error salience, as measured by the reaction time taken to correct an error (RTEC), here we argue that an evidence accumulation framework provides a potential underlying mechanism for this variable process of error identification and correction, as evidenced by covariation of frontal monitoring and parietal decision-making processes. We study two early EEG signals linked to monitoring within medial prefrontal cortex – the error-related negativity (ERN) and fronto-central theta activity – and a third EEG signal, the error positivity (Pe), that is thought to share the same parietal substrates as a signal (the P3b) proposed to reflect evidence accumulation. As predicted, our data show that on slow RTEC trials, frontal monitoring resources are less strongly employed, and the latency of the Pe is longer. Critically, the speed of the RTEC also covaries with the magnitude of subsequent neural (inter-trial alpha power) and behavioral (post-error slowing) adjustments following the correction. These results are synthesized to describe a timing diagram for adaptive decision-making after errors, and support a potential evidence accumulation mechanism in which error signaling is followed by rapid behavioral adjustments. PMID:27027420

  4. The visual parietal areas in the macaque monkey: current structural knowledge and ignorance.

    PubMed

    Cavada, C

    2001-07-01

    Classic and current parcellations of the posterior parietal cortex are reviewed. Whereas earlier studies relied on subjective observation of cortical cytoarchitecture, present parcellations are mostly based on connectional and physiological criteria. These criteria have led to the identification of five areas in the intraparietal sulcus with alleged visual function: VIP, MIP, PIP, AIP, and LIP. Other visual parietal areas are 7a, in the lateral parietal surface, and, in the medial parietal wall, 7m, and V6A. Present knowledge of the dimensions, boundaries, and connections of the various visual parietal areas is uneven: whereas LIP, 7a, and 7m have been extensively explored in anatomical and physiological studies, only scant information is available for most of the intraparietal areas. It is suggested that future studies address the anatomical and functional parcellation of the posterior parietal cortex using manifold objective means of study that allow comparison by independent researchers.

  5. Modeling Murine Gastric Metaplasia Through Tamoxifen-Induced Acute Parietal Cell Loss

    PubMed Central

    Saenz, Jose B.; Burclaff, Joseph; Mills, Jason C.

    2016-01-01

    Parietal cell loss represents the initial step in the sequential progression toward gastric adenocarcinoma. In the setting of chronic inflammation, the expansion of the mucosal response to parietal cell loss characterizes a crucial transition en route to gastric dysplasia. Here, we detail methods for using the selective estrogen receptor modulator tamoxifen as a novel tool to rapidly and reversibly induce parietal cell loss in mice in order to study the mechanisms that underlie these pre-neoplastic events. PMID:27246044

  6. Functional connectivity changes between parietal and prefrontal cortices in primary insomnia patients: evidence from resting-state fMRI

    PubMed Central

    2014-01-01

    Background Primary insomnia can severely impair daytime function by disrupting attention and working memory and imposes a danger to self and others by increasing the risk of accidents. We speculated that the neurobiological changes impeding working memory in primary insomnia patients would be revealed by resting-state functional MRI (R-fMRI), which estimates the strength of cortical pathways by measuring local and regional correlations in blood oxygen level dependent (BOLD) signs independent of specific task demands. Methods We compared the R-fMRI activity patterns of 15 healthy controls to 15 primary insomnia patients (all 30 participants were right-handed) using a 3.0 T MRI scanner. The SPM8 and REST1.7 software packages were used for preprocessing and analysis. Activity was expressed relative to the superior parietal lobe (SPL, the seed region) to reveal differences in functional connectivity to other cortical regions implicated in spatial working memory. Result In healthy controls, bilateral SPL activity was associated with activity in the posterior cingulate gyrus, precuneus, ventromedial prefrontal cortex, and superior frontal gyrus, indicating functional connectivity between these regions. Strong functional connectivity between the SPL and bilateral pre-motor cortex, bilateral supplementary motor cortex, and left dorsolateral prefrontal cortex was observed in both the control group and the primary insomnia group. However, the strength of several other functional connectivity pathways to the SPL exhibited significant group differences. Compared to healthy controls, connectivity in the primary insomnia group was stronger between the bilateral SPL and the right ventral anterior cingulate cortex, left ventral posterior cingulate cortex, right splenium of the corpus callosum, right pars triangularis (right inferior frontal gyrus/Broca’s area), and right insular lobe, while connectivity was weaker between the SPL and right superior frontal gyrus (dorsolateral

  7. Structural and functional correlates of motor imagery BCI performance: Insights from the patterns of fronto-parietal attention network.

    PubMed

    Zhang, Tao; Liu, Tiejun; Li, Fali; Li, Mengchen; Liu, Dongbo; Zhang, Rui; He, Hui; Li, Peiyang; Gong, Jinnan; Luo, Cheng; Yao, Dezhong; Xu, Peng

    2016-07-01

    Motor imagery (MI)-based brain-computer interfaces (BCIs) have been widely used for rehabilitation of motor abilities and prosthesis control for patients with motor impairments. However, MI-BCI performance exhibits a wide variability across subjects, and the underlying neural mechanism remains unclear. Several studies have demonstrated that both the fronto-parietal attention network (FPAN) and MI are involved in high-level cognitive processes that are crucial for the control of BCIs. Therefore, we hypothesized that the FPAN may play an important role in MI-BCI performance. In our study, we recorded multi-modal datasets consisting of MI electroencephalography (EEG) signals, T1-weighted structural and resting-state functional MRI data for each subject. MI-BCI performance was evaluated using the common spatial pattern to extract the MI features from EEG signals. One cortical structural feature (cortical thickness (CT)) and two measurements (degree centrality (DC) and eigenvector centrality (EC)) of node centrality were derived from the structural and functional MRI data, respectively. Based on the information extracted from the EEG and MRI, a correlation analysis was used to elucidate the relationships between the FPAN and MI-BCI performance. Our results show that the DC of the right ventral intraparietal sulcus, the EC and CT of the left inferior parietal lobe, and the CT of the right dorsolateral prefrontal cortex were significantly associated with MI-BCI performance. Moreover, the receiver operating characteristic analysis and machine learning classification revealed that the EC and CT of the left IPL could effectively predict the low-aptitude BCI users from the high-aptitude BCI users with 83.3% accuracy. Those findings consistently reveal that the individuals who have efficient FPAN would perform better on MI-BCI. Our findings may deepen the understanding of individual variability in MI-BCI performance, and also may provide a new biomarker to predict individual

  8. Within-limb somatotopic organization in human SI and parietal operculum for the leg: an fMRI study.

    PubMed

    Bao, Ruixue; Wei, Pengxu; Li, Kuncheng; Lu, Jie; Zhao, Cheng; Wang, Yuping; Zhang, Tong

    2012-03-22

    Somatotopic organizations in human somatosensory cortex (SI and SII) for scattered portions of the leg have not been systematically observed with functional magnetic resonance imaging (fMRI). In this research we compared functional representations in the contralateral SI and bilateral parietal operculum (that contained subregions OP1, 3-4 of SII and OP2) of four acupoints in right leg in proximal-distal and medial-lateral arrangement. The results were: (1) somatotopy of SI demonstrated a lateral-to-medial and inferior-to-superior pattern when acupoints were shifting from proximal to distal or from medial to lateral; (2) the contralateral OP1 also showed a clear somatotopic organization for the four separated leg portions, and the ipsilateral OP1 showed a similar pattern to the contralateral OP1, thus arrangements of responses in the two areas were mirror-symmetric against y-axis; (3) the contralateral OP2 showed a somatotopic organization when acupoints shifting from proximal to distal, while the contralateral OP3 presented a trend of somatotopy opposite to that of the contralateral OP1. These results first show definite within-leg somatotopy of human SI for scattered leg portions in medial-lateral arrangement using fMRI. Within-limb somatotopic organization of OP1 for leg portions arranging from proximal to distal as well as from medial to lateral, and somatotopy of OP2 for leg portions arranging from proximal to distal, are also shown for the first time. Our results also reinforce the proposal of a somatotopic map existing in human OP3, and indicating a fourth somatotopic map in OP2 in human parietal operculum, which suggests that OP 2 is not just a vestibular area. In addition, separable activations in somatosensory cortex induced by adjacent acupoints should play a fundamental role in acupoint-specific effects in the brain.

  9. Decompression of inferior alveolar nerve: case report.

    PubMed

    Marques, Tiago Miguel Santos; Gomes, Joana Marques

    2011-01-01

    Paresthesia as a result of mechanical trauma is one of the most frequent sensory disturbances of the inferior alveolar nerve. This case report describes surgical treatment for paresthesia caused by a compressive phenomenon within the mandibular canal. The cause of the compression, a broken instrument left in the patient's mouth during previous endodontic therapy, was identified during routine radiography and computed tomography. Once the foreign object was removed by surgery, the paresthesia resolved quickly. This case highlights the potential for an iatrogenic mechanical cause of paresthesia.

  10. Over-expression of GFP-FEZ1 causes generation of multi-lobulated nuclei mediated by microtubules in HEK293 cells

    SciTech Connect

    Lanza, Daniel C.F.; Trindade, Daniel M.; Assmann, Eliana M.; Kobarg, Joerg

    2008-06-10

    FEZ1 (Fasciculation and elongation protein zeta 1) is an ortholog of the Caenorhabditis elegans protein UNC-76, involved in neuronal development and axon outgrowth, in that worm. Mammalian FEZ1 has already been reported to cooperate with PKC-zeta in the differentiation and polarization of PC12 neuronal cells. Furthermore, FEZ1 is associated with kinesin 1 and JIP1 to form a cargo-complex responsible for microtubule based transport of mitochondria along axons. FEZ1 can also be classified as a hub protein, since it was reported to interact with over 40 different proteins in yeast two-hybrid screens, including at least nine nuclear proteins. Here, we transiently over-expressed GFP-FEZ1full in human HEK293 and HeLa cells in order to study the sub-cellular localization of GFP-FEZ1. We observed that over 40% of transiently transfected cells at 3 days post-transfection develop multi-lobulated nuclei, which are also called flower-like nuclei. We further demonstrated that GFP-FEZ1 localizes either to the cytoplasm or the nuclear fraction, and that the appearance of the flower-like nuclei depends on intact microtubule function. Finally, we show that FEZ1 co-localizes with both, {alpha}- and especially with {gamma}-tubulin, which localizes as a centrosome like structure at the center of the multiple lobules. In summary, our data suggest that FEZ1 has an important centrosomal function and supply new mechanistic insights to the formation of flower-like nuclei, which are a phenotypical hallmark of human leukemia cells.

  11. [Balint syndrome and spatial functions of the parietal lobe].

    PubMed

    Biotti, D; Pisella, L; Vighetto, A

    2012-10-01

    Balint's syndrome corresponds to the combination of optic ataxia, simultanagnosia and gaze apraxia. It generally results from a bilateral dysfunction of the posterior parietal cortex. Since its early descriptions the syndrome has been subject to many interpretations and controversies. In this article we will reconsider the current concept of Balint's syndrome. A first part will develop the clinical aspects, causes, description of symptoms, examination techniques and neuroanatomical correlations. In a second part, we will discuss how this syndrome can be included in the background of visual neurosciences, particularly through a visual attentional aspect. We will discuss the phenomenon of remapping and some recent data that may contribute to explain the pathophysiology of manifestations as optic ataxia, simultanagnosia or gaze apraxia.

  12. Diverse spatial reference frames of vestibular signals in parietal cortex

    PubMed Central

    Chen, Xiaodong; DeAngelis, Gregory C; Angelaki, Dora E

    2013-01-01

    Summary Reference frames are important for understanding how sensory cues from different modalities are coordinated to guide behavior, and the parietal cortex is critical to these functions. We compare reference frames of vestibular self-motion signals in the ventral intraparietal area (VIP), parietoinsular vestibular cortex (PIVC), and dorsal medial superior temporal area (MSTd). Vestibular heading tuning in VIP is invariant to changes in both eye and head positions, indicating a body (or world)-centered reference frame. Vestibular signals in PIVC have reference frames that are intermediate between head- and body-centered. In contrast, MSTd neurons show reference frames between head- and eye-centered, but not body-centered. Eye and head position gain fields were strongest in MSTd and weakest in PIVC. Our findings reveal distinct spatial reference frames for representing vestibular signals, and pose new challenges for understanding the respective roles of these areas in potentially diverse vestibular functions. PMID:24239126

  13. A Nexus Model of the Temporal-Parietal Junction

    PubMed Central

    Carter, R. McKell; Huettel, Scott A.

    2013-01-01

    The temporal-parietal junction (TPJ) has been proposed to support either specifically social functions or non-specific processes of cognition like memory and attention. To account for diverse prior findings, we propose a Nexus Model for TPJ function: overlap of basic processes produces novel secondary functions at their convergence. We present meta-analytic evidence that is consistent with the anatomical convergence of attention, memory, language, and social processing in the TPJ – leading to a higher-order role in the creation of a social context for behavior. The Nexus Model accounts for recent examples of TPJ contributions specifically to decision making in a social context, and it provides a potential reconciliation for competing claims about TPJ function. PMID:23790322

  14. Transient contribution of left posterior parietal cortex to cognitive restructuring

    PubMed Central

    Sutoh, Chihiro; Matsuzawa, Daisuke; Hirano, Yoshiyuki; Yamada, Makiko; Nagaoka, Sawako; Chakraborty, Sudesna; Ishii, Daisuke; Matsuda, Shingo; Tomizawa, Haruna; Ito, Hiroshi; Tsuji, Hiroshi; Obata, Takayuki; Shimizu, Eiji

    2015-01-01

    Cognitive restructuring is a fundamental method within cognitive behavioural therapy of changing dysfunctional beliefs into flexible beliefs and learning to react appropriately to the reality of an anxiety-causing situation. To clarify the neural mechanisms of cognitive restructuring, we designed a unique task that replicated psychotherapy during a brain scan. The brain activities of healthy male participants were analysed using functional magnetic resonance imaging. During the brain scan, participants underwent Socratic questioning aimed at cognitive restructuring regarding the necessity of handwashing after using the restroom. The behavioural result indicated that the Socratic questioning effectively decreased the participants' degree of belief (DOB) that they must wash their hands. Alterations in the DOB showed a positive correlation with activity in the left posterior parietal cortex (PPC) while the subject thought about and rated own belief. The involvement of the left PPC not only in planning and decision-making but also in conceptualization may play a pivotal role in cognitive restructuring. PMID:25775998

  15. Scalp Medical Tattooing Technique to Camouflage Bifid Parietal Whorls

    PubMed Central

    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

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

    PubMed

    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

  17. The Brain Adapts to Orthography with Experience: Evidence from English and Chinese

    ERIC Educational Resources Information Center

    Cao, Fan; Brennan, Christine; Booth, James R.

    2015-01-01

    Using functional magnetic resonance imaging (fMRI), we examined the process of language specialization in the brain by comparing developmental changes in two contrastive orthographies: Chinese and English. In a visual word rhyming judgment task, we found a significant interaction between age and language in left inferior parietal lobule and left…

  18. A longitudinal study of the relationship between personality traits and the annual rate of volume changes in regional gray matter in healthy adults.

    PubMed

    Taki, Yasuyuki; Thyreau, Benjamin; Kinomura, Shigeo; Sato, Kazunori; Goto, Ryoi; Wu, Kai; Kawashima, Ryuta; Fukuda, Hiroshi

    2013-12-01

    To investigate whether personality traits affect the rate of decline of gray matter volume, we analyzed the relationships between personality traits and the annual rate of changes of gray matter volume in 274 healthy community dwelling subjects with a large age range by applying a longitudinal design over 6 years, using brain magnetic resonance images (MRI) and the Revised NEO Personality Inventory (NEO-PI-R) at baseline. Brain MRI data were processed using voxel-based morphometry with a custom template by applying the DARTEL diffeomorphic registration tool. For each subject, we used NEO-PI-R to evaluate the five major personality traits, including neuroticism, extraversion, openness, agreeableness, and conscientiousness. The results show that the annual rate of change in regional gray matter volume in the right inferior parietal lobule was correlated significantly and negatively with a personality of openness, which is known to be related to intellect, intellectual curiosity, and creativity adjusting for age, gender, and intracranial volume. This result indicates that subjects with a personality trait of less openness have an accelerated loss of gray matter volume in the right inferior parietal lobule, compared with subjects with a personality trait of more openness. Because the right inferior parietal lobule is involved in higher cognitive function such as working memory and creativity, a personality trait of openness is thought to be important for preserving gray matter volume and cognitive function of the right inferior parietal lobule in healthy adults.

  19. Holding Biological Motion in Working Memory: An fMRI Study

    PubMed Central

    Lu, Xiqian; Huang, Jian; Yi, Yuji; Shen, Mowei; Weng, Xuchu; Gao, Zaifeng

    2016-01-01

    Holding biological motion (BM), the movements of animate entities, in working memory (WM) is important to our daily life activities. However, the neural substrates underlying the WM processing of BM remain largely unknown. Employing the functional magnetic resonance imaging (fMRI) technique, the current study directly investigated this issue. We used point-light BM animations as the tested stimuli, and explored the neural substrates involved in encoding and retaining BM information in WM. Participants were required to remember two or four BM stimuli in a change-detection task. We first defined a set of potential brain regions devoted to the BM processing in WM in one experiment. We then conducted the second fMRI experiment, and performed time-course analysis over the pre-defined regions, which allowed us to differentiate the encoding and maintenance phases of WM. The results showed that a set of brain regions were involved in encoding BM into WM, including the middle frontal gyrus, inferior frontal gyrus, superior parietal lobule, inferior parietal lobule, superior temporal sulcus, fusiform gyrus, and middle occipital gyrus. However, only the middle frontal gyrus, inferior frontal gyrus, superior parietal lobule, and inferior parietal lobule were involved in retaining BM into WM. These results suggest that an overlapped network exists between the WM encoding and maintenance for BM; however, retaining BM in WM predominately relies on the mirror neuron system. PMID:27313520

  20. Possible role of an error detection mechanism in brain processing of deception: PET-fMRI study.

    PubMed

    Kireev, Maxim; Korotkov, Alexander; Medvedeva, Natalia; Medvedev, Svyatoslav

    2013-12-01

    To investigate brain maintenance of deliberate deception the positron emission tomography and the event related functional MRI studies were performed. We used an experimental paradigm that presupposed free choices between equally beneficial deceptive or honest actions. Experimental task simulated the "Cheat" card game which aims to defeat an opponent by sequential deceptive and honest claims. Results of both the PET and the fMRI studies revealed that execution of both deliberately deceptive and honest claims is associated with fronto-parietal brain network comprised of inferior and middle frontal gyri, precentral gyrus (BA 6), caudate nucleus, and inferior parietal lobule. Direct comparison between those claims, balanced in terms of decision making and action outcome (gain and losses), revealed activation of areas specifically associated with deception execution: precentral gyrus (BA 6), caudate nuclei, thalamus and inferior parietal lobule (BA 39/40). The obtained experimental data were discussed in relation to a possible role of an error detection system in processing deliberate deception.

  1. Differences in biomechanical properties and thickness among frontal and parietal bones in a Japanese sample.

    PubMed

    Torimitsu, Suguru; Nishida, Yoshifumi; Takano, Tachio; Yajima, Daisuke; Inokuchi, Go; Makino, Yohsuke; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2015-07-01

    The aim of this study was to assess the mechanical properties and thickness of adult frontal and parietal bones. The heads of 114 Japanese cadavers (78 male cadavers and 36 female cadavers) of known age and sex were used. A total of 912 cranial samples, 8 from each skull, were collected. Samples were imaged using multidetector computed tomography to measure sample thickness. The fracture load of each sample was measured using a bending test with calculation of flexural strength. Statistical analyses demonstrated no significant bilateral difference in either the mechanical properties or thickness of frontal or parietal bones. The mechanical properties and thicknesses of frontal bones were significantly greater than those of parietal bones regardless of sex. Therefore, the skull may have a great ability to resist frontal impacts compared with parietal impacts. In female samples, parietal bones were found to have a more uniform structure when compared with male samples. Male parietal bones were found to be thicker at medial sites than at lateral sites. This study also revealed parietal bones at lateral sites in female samples were thicker than in male samples. No strong association was observed between age and flexural strength of frontal or parietal bones. However, the fracture load was negatively correlated with age most likely due to the reduction of thickness.

  2. The Role of Right and Left Parietal Lobes in the Conceptual Processing of Numbers

    ERIC Educational Resources Information Center

    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,…

  3. Role of parietal regions in episodic memory retrieval: the dual attentional processes hypothesis.

    PubMed

    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.

  4. Frontal and parietal EEG asymmetries interact to predict attentional bias to threat.

    PubMed

    Grimshaw, Gina M; Foster, Joshua J; Corballis, Paul M

    2014-10-01

    Frontal and parietal electroencephalographic (EEG) asymmetries mark vulnerability to depression and anxiety. Drawing on cognitive theories of vulnerability, we hypothesise that cortical asymmetries predict attention to threat. Participants completed a dot-probe task in which bilateral face displays were followed by lateralised targets at either short (300ms) or long (1050ms) SOA. We also measured N2pc to face onset as an index of early attentional capture. At long SOA only, frontal and parietal asymmetry interacted to predict attentional bias to angry faces. Those with leftward frontal asymmetry showed no attentional bias. Among those with rightward frontal asymmetry those with low right parietal activity showed vigilance for threat, and those with high right parietal activity showed avoidance. Asymmetry was not related to the N2pc or to attentional bias at the short SOA. Findings suggest that trait asymmetries reflect function in a fronto-parietal network that controls attention to threat.

  5. 10 Hz rTMS over right parietal cortex alters sense of agency during self-controlled movements

    PubMed Central

    Ritterband-Rosenbaum, Anina; Karabanov, Anke N.; Christensen, Mark S.; Nielsen, Jens Bo

    2014-01-01

    A large body of fMRI and lesion-literature has provided evidence that the Inferior Parietal Cortex (IPC) is important for sensorimotor integration and sense of agency (SoA). We used repetitive transcranial magnetic stimulation (rTMS) to explore the role of the IPC during a validated SoA detection task. 12 healthy, right-handed adults were included. The effects of rTMS on subjects' SoA during self-controlled movements were explored. The experiment consisted of 1/3 self-controlled movements and 2/3 computer manipulated movements that introduced uncertainty as to whether the subjects were agents of an observed movement. Subjects completed three sessions, in which subjects received online rTMS over the right IPC (active condition), over the vertex (CZ) (sham condition) or no TMS but a sound-matched control. We found that rTMS over right IPC significantly altered SoA of the non-perturbed movements. Following IPC stimulation subjects were more likely to experience self-controlled movements as being externally perturbed compared to the control site (P = 0.002) and the stimulation-free control (P = 0.042). The data support the importance of IPC activation during sensorimotor comparison in order to correctly determine the agent of movements. PMID:25009489

  6. Gray matter increases in fronto-parietal regions of depression patients with aripiprazole monotherapy: An exploratory study.

    PubMed

    Lai, Chien-Han; Wu, Yu-Te; Chen, Cheng-Yu; Hou, Yi-Cheng

    2016-08-01

    We investigated the treatment effects of aripiprazole monotherapy in first-episode medication-naïve patients with major depressive disorder (MDD). The accompanying changes in the gray matter volume (GMV) were also explored.Fifteen patients completed the trial and received structural scans by 3-Tesla magnetic resonance imaging at baseline and partially responding state (sixth week). To account for the test-retest bias, 27 healthy controls were scanned twice within 6 weeks. We utilized optimized voxel-based morphometry with different comparisons between groups.The partially responding patients with MDD had greater GMV in left middle frontal gyrus and left superior parietal gyrus when compared with baseline. However, they had decreases in the GMV of right orbitofrontal gyrus and right inferior temporal gyrus after response. The partially responding patients with MDD still had residual GMV deficits in right superior frontal gyrus when compared with controls. However, the lack of second patient group without aripiprazole intervention would be a significant limitation to interpret the aripiprazole-specific effects on GMV.The changes in the GMV of fronto-parieto-temporal regions and residual GMV deficits in the superior frontal gyrus might represent "state-dependent brain changes" and "residual-deficit brain regions," respectively, for aripiprzole monotherapy in MDD.

  7. Partial breast reconstruction with mini superficial inferior epigastric artery and mini deep inferior epigastric perforator flaps.

    PubMed

    Spiegel, Aldona J; Eldor, Liron

    2010-08-01

    In this study, partial breast reconstruction was undertaken after breast conservation therapy using mini abdominal free flaps on both an immediate and delayed basis.Patient demographics, oncologic status, reconstructive data, and complications were collected from medical records.Twelve patients (age range 39-60) were included in this study with a mean follow-up time of 5 years. Ten mini superficial inferior epigastric artery flaps and 2 mini deep inferior epigastric perforator flaps were used (7 immediate and 5 delayed reconstructions). No flap lost, 1 minor abdominal wound dehiscence, and no local or distant recurrences were noted. Good to excellent results were reported by 91% of the women.In properly selected patients with high motivation toward breast conservation, tailored abdominal mini-free flaps can safely and satisfactorily be implemented for the reconstruction of partial mastectomy defects. Patients should be comprehensively educated on the potential future implications of using the abdominal donor site for partial breast reconstruction.

  8. Across-study and within-subject functional connectivity of a right temporo-parietal junction subregion involved in stimulus-context integration.

    PubMed

    Jakobs, Oliver; Langner, Robert; Caspers, Svenja; Roski, Christian; Cieslik, Edna C; Zilles, Karl; Laird, Angela R; Fox, Peter T; Eickhoff, Simon B

    2012-05-01

    Bidirectional integration between sensory stimuli and contextual framing is fundamental to action control. Stimuli may entail context-dependent actions, while temporal or spatial characteristics of a stimulus train may establish a contextual framework for upcoming stimuli. Here we aimed at identifying core areas for stimulus-context integration and delineated their functional connectivity (FC) using meta-analytic connectivity modeling (MACM) and analysis of resting-state networks. In a multi-study conjunction, consistently increased activity under higher demands on stimulus-context integration was predominantly found in the right temporo-parietal junction (TPJ), which represented the largest cluster of overlap and was thus used as the seed for the FC analyses. The conjunction between task-dependent (MACM) and task-free (resting state) FC of the right TPJ revealed a shared network comprising bilaterally inferior parietal and frontal cortices, anterior insula, premotor cortex, putamen and cerebellum, i.e., a 'ventral' action/attention network. Stronger task-dependent (vs. task-free) connectivity was observed with the pre-SMA, dorsal premotor cortex, intraparietal sulcus, basal ganglia and primary sensori motor cortex, while stronger resting-state (vs. task-dependent) connectivity was found with the dorsolateral prefrontal and medial parietal cortex. Our data provide strong evidence that the right TPJ may represent a key region for the integration of sensory stimuli and contextual frames in action control. Task-dependent associations with regions related to stimulus processing and motor responses indicate that the right TPJ may integrate 'collaterals' of sensory processing and apply (ensuing) contextual frames, most likely via modulation of preparatory loops. Given the pattern of resting-state connectivity, internal states and goal representations may provide the substrates for the contextual integration within the TPJ in the absence of a specific task.

  9. Increased prefrontal and parietal cortical thickness does not correlate with anhedonia in patients with untreated first-episode major depressive disorders.

    PubMed

    Yang, Xin-hua; Wang, Yi; Huang, Jia; Zhu, Cui-ying; Liu, Xiao-qun; Cheung, Eric F C; Xie, Guang-rong; Chan, Raymond C K

    2015-10-30

    Cerebral morphological abnormalities in major depressive disorder (MDD) may be modulated by antidepressant treatment and course of illness in chronic medicated patients. The present study examined cortical thickness in patients with untreated first-episode MDD to elucidate the early pathophysiology of this illness. Here, we examined cortical thickness in patients with first-episode MDD (N=27) and healthy controls (N=27) using an automated surface-based method (in FreeSurfer). By assessing the correlation between caudate volume and cortical thickness at each vertex on the cortical surface, a caudate-cortical network was obtained for each group. Subsequent analysis was performed to assess the effect of anhedonia by the Temporal Experience of Pleasure Scale. We observed increased cortical thickness at the right orbital frontal cortex and the left inferior parietal gyrus in MDD patients compared with healthy controls. Furthermore, morphometric correlational analysis using cortical thickness measurement revealed increased caudate-cortical connectivity in the bilateral superior parietal gyrus in MDD patients. All changes were not related to anhedonia. These preliminary findings may reflect disorder manifestation close to illness onset and may provide insight into the early neurobiology of MDD.

  10. Visuo-motor integration and control in the human posterior parietal cortex: evidence from TMS and fMRI.

    PubMed

    Iacoboni, Marco

    2006-01-01

    The posterior parietal cortex is a fundamental structure for visuo-motor integration and control. Here I discuss recent transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) studies that I interpret as suggesting four concepts. The evolutionary process has enlarged the human posterior parietal cortex while still preserving the internal structure of the posterior parietal cortex of other primates. Visuo-motor control in the posterior parietal cortex may be implemented by coding primarily action goals. The lateralization of visuo-motor functions in the posterior parietal cortex suggests that the left posterior parietal cortex is more concerned with tool use and the right posterior parietal cortex is more concerned with imitation of the actions of others. Finally, visuo-motor inter-hemispheric transfer through parietal callosal fibers occurs at the level of 'motor intention'.

  11. Morphogenesis of callosal arbors in the parietal cortex of hamsters.

    PubMed

    Hedin-Pereira, C; Lent, R; Jhaveri, S

    1999-01-01

    The morphogenesis of callosal axons originating in the parietal cortex was studied by anterograde labeling with Phaseolus lectin or biocytin injected in postnatal (P) hamsters aged 7-25 days. Some labeled fibers were serially reconstructed. At P7, some callosal fibers extended as far as the contralateral rhinal fissure, with simple arbors located in the homotopic region of the opposite cortical gray matter, and two or three unbranched sprouts along their trajectory. From P7 to P13, the homotopic arbors became more complex, with branches focused predominantly, but not exclusively, in the supra- and infragranular layers of the homotopic region. Simultaneously, the lateral extension of the trunk axon in the white matter became shorter, finally disappearing by P25. Arbors in the gray matter were either bilaminar (layers 2/3 and 5) or supragranular. A heterotopic projection to the lateral cortex was consistently seen at all ages; the heterotopic arbors follow a similar sequence of events to that seen in homotopic regions. These observations document that callosal axons undergo regressive tangential remodeling during the first postnatal month, as the lateral extension of the trunk fiber gets eliminated. Radially, however, significant arborization occurs in layer-specific locations. The protracted period of morphogenesis suggests a correspondingly long plastic period for this system of cortical fibers.

  12. True and false memories, parietal cortex, and confidence judgments.

    PubMed

    Urgolites, Zhisen J; Smith, Christine N; Squire, Larry R

    2015-11-01

    Recent studies have asked whether activity in the medial temporal lobe (MTL) and the neocortex can distinguish true memory from false memory. A frequent complication has been that the confidence associated with correct memory judgments (true memory) is typically higher than the confidence associated with incorrect memory judgments (false memory). Accordingly, it has often been difficult to know whether a finding is related to memory confidence or memory accuracy. In the current study, participants made recognition memory judgments with confidence ratings in response to previously studied scenes and novel scenes. The left hippocampus and 16 other brain regions distinguished true and false memories when confidence ratings were different for the two conditions. Only three regions (all in the parietal cortex) distinguished true and false memories when confidence ratings were equated. These findings illustrate the utility of taking confidence ratings into account when identifying brain regions associated with true and false memories. Neural correlates of true and false memories are most easily interpreted when confidence ratings are similar for the two kinds of memories.

  13. The planar cell polarity pathway directs parietal endoderm migration.

    PubMed

    LaMonica, Kristi; Bass, Maya; Grabel, Laura

    2009-06-01

    Parietal endoderm (PE) contributes to the yolk sac and is the first migratory cell type in the mammalian embryo. We can visualize PE migration in vitro using the F9 teratocarcinoma derived embryoid body outgrowth system and, show here that PE migration is directed by the non-canonical Wnt planar cell polarity (PCP) pathway via Rho/ROCK. Based on golgi apparatus localization and microtubule orientation, 68.6% of cells in control outgrowths are oriented in the direction of migration. Perturbation of Wnt signaling via sFRP treatment results in a loss of orientation coupled with an increase in cell migration. Inhibition of the PCP pathway at the level of Daam1 also results in a loss of cell orientation along with an increase in cell migration, as seen with sFRP treatment. Constitutively active Daam can inhibit the loss of orientation that occurs with sFRP treatment. We previously demonstrated that ROCK inhibition leads to an increase in cell migration, and we now show that these cells also lack oriented migration. Canonical Wnt signaling or the Rac arm of the PCP pathway does not appear to play a role in PE oriented migration. These data suggest the PCP pathway via Rho/ROCK modulates migration of PE.

  14. Cyclodextrin modified PLLA parietal reinforcement implant with prolonged antibacterial activity.

    PubMed

    Vermet, G; Degoutin, S; Chai, F; Maton, M; Flores, C; Neut, C; Danjou, P E; Martel, B; Blanchemain, N

    2017-02-12

    The use of textile meshes in hernia repair is widespread in visceral surgery. Though, mesh infection is a complication that may prolong the patient recovery period and consequently presents an impact on public health economy. Such concern can be avoided thanks to a local and extended antibiotic release on the operative site. In recent developments, poly-l-lactic acid (PLLA) has been used in complement of polyethyleneterephthalate (Dacron®) (PET) or polypropylene (PP) yarns in the manufacture of semi-resorbable parietal implants. The goal of the present study consisted in assigning drug reservoir properties and prolonged antibacterial effect to a 100% PLLA knit through its functionalization with a cyclodextrin polymer (polyCD) and activation with ciprofloxacin. The study focused i) on the control of degree of polyCD functionalization of the PLLA support and on its physical and biological characterization by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC) and cell viability, ii) on the understanding of drug/meshes interaction using mathematic model and iii) on the correlation between drug release studies in phosphate buffer saline (PBS) and microbiological evaluation of meshes and release medium against E. coli and S. aureus. All above mentioned tests highlighted the contribution of polyCD on the improved performances of the resulting antibacterial implantable material.

  15. TMS of posterior parietal cortex disrupts visual tactile multisensory integration.

    PubMed

    Pasalar, Siavash; Ro, Tony; Beauchamp, Michael S

    2010-05-01

    Functional neuroimaging studies have implicated a number of brain regions, especially the posterior parietal cortex (PPC), as being potentially important for visual-tactile multisensory integration. However, neuroimaging studies are correlational and do not prove the necessity of a region for the behavioral improvements that are the hallmark of multisensory integration. To remedy this knowledge gap, we interrupted activity in the PPC, near the junction of the anterior intraparietal sulcus and the postcentral sulcus, using MRI-guided transcranial magnetic stimulation (TMS) while subjects localized touches delivered to different fingers. As the touches were delivered, subjects viewed a congruent touch video, an incongruent touch video, or no video. Without TMS, a strong effect of multisensory integration was observed, with significantly better behavioral performance for discrimination of congruent multisensory touch than for unisensory touch alone. Incongruent multisensory touch produced a smaller improvement in behavioral performance. TMS of the PPC eliminated the behavioral advantage of both congruent and incongruent multisensory stimuli, reducing performance to unisensory levels. These results demonstrate a causal role for the PPC in visual-tactile multisensory integration. Taken together with converging evidence from other studies, these results support a model in which the PPC contains a map of space around the hand that receives input from both the visual and somatosensory modalities. Activity in this map is likely to be the neural substrate for visual-tactile multisensory integration.

  16. The posterior parietal cortex remaps touch into external space.

    PubMed

    Azañón, Elena; Longo, Matthew R; Soto-Faraco, Salvador; Haggard, Patrick

    2010-07-27

    Localizing tactile events in external space is required for essential functions such as orienting, haptic exploration, and goal-directed action in peripersonal space. In order to map somatosensory input into a spatiotopic representation, information about skin location must be integrated with proprioceptive information about body posture. We investigated the neural bases of this tactile remapping mechanism in humans by disrupting neural activity in the putative human homolog of the monkey ventral intraparietal area (hVIP), within the right posterior parietal cortex (rPPC), which is thought to house external spatial representations. Participants judged the elevation of touches on their (unseen) forearm relative to touches on their face. Arm posture was passively changed along the vertical axis, so that elevation judgments required the use of an external reference frame. Single-pulse transcranial magnetic stimulation (TMS) over the rPPC significantly impaired performance compared to a control site (vertex). Crucially, proprioceptive judgments of arm elevation or tactile localization on the skin remained unaffected by rPPC TMS. This selective disruption of tactile remapping suggests a distinct computational process dissociable from pure proprioceptive and somatosensory localization. Furthermore, this finding highlights the causal role of human PPC, putatively VIP, in remapping touch into external space.

  17. Converging functional magnetic resonance imaging evidence for a role of the left inferior frontal lobe in semantic retention during language comprehension.

    PubMed

    Hamilton, A Cris; Martin, Randi C; Burton, Philip C

    2009-12-01

    Increasing evidence supports dissociable short-term memory (STM) capacities for semantic and phonological representations. Cognitive neuropsychological data suggest that damage to the left inferior and middle frontal gyri are associated with deficits of semantic STM, while damage to inferior parietal areas is associated with deficits of phonological STM. Patients identified as having semantic STM deficits are also impaired on a number of language comprehension and production paradigms. We used one such comprehension task derived from cognitive neuropsychological data to test predictions with functional magnetic resonance imaging (fMRI) using healthy participants. Using a task that required participants to make semantic anomaly judgements, we found significantly greater activation in areas of the left inferior frontal and middle frontal gyri for phrases that required maintenance of multiple words for eventual integration with a subsequent noun or verb. These data are consistent with our previous patient studies (Hanten & Martin, 2000; R. C. Martin & He, 2004; R. C. Martin & Romani, 1994 ) that suggest that semantic STM is associated with the left inferior and middle frontal gyri and that deficits of semantic STM have particular consequences for comprehension tasks that require maintenance of several word meanings in unintegrated form.

  18. Inferior frontal oscillations reveal visuo-motor matching for actions and speech: evidence from human intracranial recordings.

    PubMed

    Halje, Pär; Seeck, Margitta; Blanke, Olaf; Ionta, Silvio

    2015-12-01

    The neural correspondence between the systems responsible for the execution and recognition of actions has been suggested both in humans and non-human primates. Apart from being a key region of this visuo-motor observation-execution matching (OEM) system, the human inferior frontal gyrus (IFG) is also important for speech production. The functional overlap of visuo-motor OEM and speech, together with the phylogenetic history of the IFG as a motor area, has led to the idea that speech function has evolved from pre-existing motor systems and to the hypothesis that an OEM system may exist also for speech. However, visuo-motor OEM and speech OEM have never been compared directly. We used electrocorticography to analyze oscillations recorded from intracranial electrodes in human fronto-parieto-temporal cortex during visuo-motor (executing or visually observing an action) and speech OEM tasks (verbally describing an action using the first or third person pronoun). The results show that neural activity related to visuo-motor OEM is widespread in the frontal, parietal, and temporal regions. Speech OEM also elicited widespread responses partly overlapping with visuo-motor OEM sites (bilaterally), including frontal, parietal, and temporal regions. Interestingly a more focal region, the inferior frontal gyrus (bilaterally), showed both visuo-motor OEM and speech OEM properties independent of orolingual speech-unrelated movements. Building on the methodological advantages in human invasive electrocorticography, the present findings provide highly precise spatial and temporal information to support the existence of a modality-independent action representation system in the human brain that is shared between systems for performing, interpreting and describing actions.

  19. Phenotypic and Genetic Correlations Between the Lobar Segments of the Inferior Fronto-occipital Fasciculus and Attention

    PubMed Central

    Leng, Yuan; Shi, Yonggang; Yu, Qiaowen; Van Horn, John Darrell; Tang, Haiyan; Li, Junning; Xu, Wenjian; Ge, Xinting; Tang, Yuchun; Han, Yan; Zhang, Dong; Xiao, Min; Zhang, Huaqiang; Pang, Zengchang; Toga, Arthur W.; Liu, Shuwei

    2016-01-01

    Attention deficits may present dysfunctions in any one or two components of attention (alerting, orienting, and executive control (EC)). However, these various forms of attention deficits generally have abnormal microstructure integrity of inferior fronto-occipital fasciculus (IFOF). In this work, we aim to deeply explore: (1) associations between microstructure integrities of IFOF (including frontal, parietal, temporal, occipital, and insular segments) and attention by means of structural equation models and multiple regression analyses; (2) genetic/environmental effects on IFOF, attention, and their correlations using bivariate genetic analysis. EC function was attributed to the fractional anisotropy (FA) of left (correlation was driven by genetic and environmental factors) and right IFOF (correlation was driven by environmental factors), especially to left frontal part and right occipital part (correlation was driven by genetic factors). Alerting was associated with FA in parietal and insular parts of left IFOF. No significant correlation was found between orienting and IFOF. This study revealed the advantages of lobar-segmental analysis in structure-function correlation study and provided the anatomical basis for kinds of attention deficits. The common genetic/environmental factors implicated in the certain correlations suggested the common physiological mechanisms for two traits, which should promote the discovery of single-nucleotide polymorphisms affecting IFOF and attention. PMID:27597294

  20. The parietal cortex and saccade planning: lessons from human lesion studies.

    PubMed

    Ptak, Radek; Müri, René M

    2013-01-01

    The parietal cortex is a critical interface for attention and integration of multiple sensory signals that can be used for the implementation of motor plans. Many neurons in this region exhibit strong attention-, reach-, grasp- or saccade-related activity. Here, we review human lesion studies supporting the critical role of the parietal cortex in saccade planning. Studies of patients with unilateral parietal damage and spatial neglect reveal characteristic spatially lateralized deficits of saccade programming when multiple stimuli compete for attention. However, these patients also show bilateral impairments of saccade initiation and control that are difficult to explain in the context of their lateralized deficits of visual attention. These findings are reminiscent of the deficits of oculomotor control observed in patients with Bálint's syndrome consecutive to bilateral parietal damage. We propose that some oculomotor deficits following parietal damage are compatible with a decisive role of the parietal cortex in saccade planning under conditions of sensory competition, while other deficits reflect disinhibition of low-level structures of the oculomotor network in the absence of top-down parietal modulation.

  1. Cortical connectivity maps reveal anatomically distinct areas in the parietal cortex of the rat.

    PubMed

    Wilber, Aaron A; Clark, Benjamin J; Demecha, Alexis J; Mesina, Lilia; Vos, Jessica M; McNaughton, Bruce L

    2014-01-01

    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 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.

  2. Uses of the Inferior Oblique Muscle in Strabismus Surgery

    PubMed Central

    Stager, David; Dao, Lori M.; Felius, Joost

    2015-01-01

    Inferior oblique muscle weakening is typically performed for overaction of the muscle. In this article, we review inferior oblique muscle anatomy, different weakening procedures, and recent surgical techniques that take advantage of the muscle's unique anatomy for the treatment of additional indications such as excyclotorsion and hypertropia in primary gaze. PMID:26180466

  3. A Neuropsychological Examination of the Underlying Deficit in Attention Deficit Hyperactivity Disorder: Frontal Lobe Versus Right Parietal Lobe Theories.

    ERIC Educational Resources Information Center

    Aman, Christine J.; Roberts, Ralph J., Jr.; Pennington, Bruce F.

    1998-01-01

    Examined front and right parietal lobe theories of attention deficit hyperactivity disorder (ADHD); subjects were 10- to 14-year-old boys with or without ADHD. Found that non-ADHD boys performed better on frontal- and parietal-domain tasks than unmedicated ADHD boys, unmedicated AHDH boys had greater impairments on frontal than parietal tasks, and…

  4. Massive acinar cell apoptosis with secondary necrosis, origin of ducts in atrophic lobules and failure to regenerate in cyanohydroxybutene pancreatopathy in rats

    PubMed Central

    Kelly, Lyndell; Reid, Lynne; Walker, Neal I

    1999-01-01

    Cyanohydroxybutene (CHB), a glycosinolate breakdown product, causes pancreatic injury when given to animals in large amounts. To determine the course of CHB-induced pancreatopathy, rats were given a single subcutaneous dose of CHB and the pancreas weighed and examined by light and electron microscopy and immunohistochemistry at intervals from 2 h to 28 days. The pancreatic lesion was unusual in that there was marked early oedema with limited inflammatory cell infiltration, rapid synchronous onset of acinar cell apoptosis and early advanced atrophy engendering only a limited regenerative response. Acinar cell apoptosis was atypical in that cell fragmentation was limited and phagocytosis delayed, resulting in extensive secondary necrosis. As ducts were unaffected by CHB, the crowded ducts making up the epithelial component of atrophic lobules could be clearly shown to derive from their condensation and proliferation, not the redifferentiation of pre-existing acinar cells, widely held to produce this lesion. Although the basis of CHB selectivity and toxicity for pancreatic acinar cells remains unknown, the potential therapeutic benefit of such an agent in patients with pancreatitis or pancreatic tumours warrants further investigation. PMID:10583631

  5. Effect of short- and long-term alcohol feeding in rats on pancreatic enzyme content and enzyme secretion in isolated pancreatic lobules in vitro.

    PubMed

    Bode, C; Dürr, H K; Bode, J C

    1986-07-01

    The effect of short- and long-term ethanol intake on digestive enzyme secretion was determined in isolated pancreatic lobules of rats. Groups of male Wistar rats were fed a modified Lieber-DeCarli diet containing either 5% (w/v) of ethanol, isocaloric amounts of a liquid diet in which ethanol was substituted by starch, or solid rat chow; for 3 days, 1, 2, 4, 8 and 12 weeks. Basal and caerulein-stimulated secretion of lipase, amylase, chymotrypsin and trypsin and the enzyme content in the tissue were studied. Feeding the liquid control diet decreased the tissue content of the four enzymes as compared with the values obtained in the group receiving solid rat chow. While basal and stimulated amylase secretion was markedly reduced in the former group, the secretion pattern of the other enzymes exhibited only transient changes. Caerulein-stimulated secretion of lipase and the proteases was increased by ethanol, the effect being more pronounced during the initial phase of the experiment. Alcohol feeding stimulated the basal secretion of these enzymes only in weeks 1-4. In contrast to the other enzymes, basal and stimulated amylase secretion was not enhanced by ethanol feeding. The results suggest that the enzyme secretion of the rat pancreas is distinctly altered by chronic ethanol feeding. However, the response of the pancreatic enzymes is non-parallel, and changes with the duration of alcohol intake.

  6. Complications of inferior vena cava filters

    PubMed Central

    Grewal, Simer; Chamarthy, Murthy R.

    2016-01-01

    Inferior vena cava (IVC) filter placement is a relatively low risk alternative for prophylaxis against pulmonary embolism in patients with pelvic or lower extremity deep venous thrombosis who are not suitable for anticoagulation. There is an increasing trend in the number of IVC filter implantation procedures performed every year. There are many device types in the market and in the early 2000s, the introduction of retrievable filters brought an additional subset of complications to consider. Modern filter designs have led to decreased morbidity and mortality, however, a thorough understanding of the limitations and complications of IVC filters is necessary to weight the risks and benefits of placing IVC filters. In this review, the complications associated with IVC filters are divided into procedure related, post-procedure, and retrieval complications. Differences amongst the device types and retrievable filters are described, though this is limited by a significant lack of prospective studies. Additionally, the clinical presentation as well as prevention and treatment strategies are outlined with each complication type. PMID:28123983

  7. Where are your body parts? A pure case of heterotopagnosia following left parietal stroke.

    PubMed

    Auclair, Laurent; Noulhiane, Marion; Raibaut, Patrick; Amarenco, Gerard

    2009-12-01

    We studied the involvement of the parietal cortex in interpersonal body representation in a left parietal stroke patient. We used tasks assessing different types of body representations and localization of object parts. The patient performed normally on all tasks of body knowledge. However, she was unable to locate body parts on another person or on body representations. In contrast, she pointed correctly to the same body parts on herself or object representations. The data support the important role of the left parietal cortex in the transformation of intrinsic spatial coding of body parts localization in extrinsic body part coordinates.

  8. Potential relationship of self-injurious behavior to right temporo-parietal lesions.

    PubMed

    Borah, Shaina; McConnell, Brice; Hughes, Richard; Kluger, Benzi

    2016-06-01

    Self-injurious behavior (SIB) is associated with several neurologic and psychiatric syndromes but rarely with focal lesions. Two patients with lesions of the right temporo-parietal junction presented to psychiatric inpatient services with SIB in the absence of notable neurologic deficits or suicidal ideation. Right temporo-parietal lesions may be associated with disturbances of agency and body ownership, both of which may facilitate SIB. Misoplegia, or hatred of a limb, may be associated with SIB and has been reported without hemiplegia with a right temporo-parietal lesion. Further study is warranted to improve our understanding of the mechanisms underlying SIB.

  9. A frontal but not parietal neural correlate of auditory consciousness.

    PubMed

    Brancucci, Alfredo; Lugli, Victor; Perrucci, Mauro Gianni; Del Gratta, Cosimo; Tommasi, Luca

    2016-01-01

    Hemodynamic correlates of consciousness were investigated in humans during the presentation of a dichotic sequence inducing illusory auditory percepts with features analogous to visual multistability. The sequence consisted of a variation of the original stimulation eliciting the Deutsch's octave illusion, created to maintain a stable illusory percept long enough to allow the detection of the underlying hemodynamic activity using functional magnetic resonance imaging (fMRI). Two specular 500 ms dichotic stimuli (400 and 800 Hz) presented in alternation by means of earphones cause an illusory segregation of pitch and ear of origin which can yield up to four different auditory percepts per dichotic stimulus. Such percepts are maintained stable when one of the two dichotic stimuli is presented repeatedly for 6 s, immediately after the alternation. We observed hemodynamic activity specifically accompanying conscious experience of pitch in a bilateral network including the superior frontal gyrus (SFG, BA9 and BA10), medial frontal gyrus (BA6 and BA9), insula (BA13), and posterior lateral nucleus of the thalamus. Conscious experience of side (ear of origin) was instead specifically accompanied by bilateral activity in the MFG (BA6), STG (BA41), parahippocampal gyrus (BA28), and insula (BA13). These results suggest that the neural substrate of auditory consciousness, differently from that of visual consciousness, may rest upon a fronto-temporal rather than upon a fronto-parietal network. Moreover, they indicate that the neural correlates of consciousness depend on the specific features of the stimulus and suggest the SFG-MFG and the insula as important cortical nodes for auditory conscious experience.

  10. Hand Shape Representations in the Human Posterior Parietal Cortex

    PubMed Central

    Klaes, Christian; Kellis, Spencer; Aflalo, Tyson; Lee, Brian; Pejsa, Kelsie; Shanfield, Kathleen; Hayes-Jackson, Stephanie; Aisen, Mindy; Heck, Christi; Liu, Charles

    2015-01-01

    Humans shape their hands to grasp, manipulate objects, and to communicate. From nonhuman primate studies, we know that visual and motor properties for grasps can be derived from cells in the posterior parietal cortex (PPC). Are non-grasp-related hand shapes in humans represented similarly? Here we show for the first time how single neurons in the PPC of humans are selective for particular imagined hand shapes independent of graspable objects. We find that motor imagery to shape the hand can be successfully decoded from the PPC by implementing a version of the popular Rock-Paper-Scissors game and its extension Rock-Paper-Scissors-Lizard-Spock. By simultaneous presentation of visual and auditory cues, we can discriminate motor imagery from visual information and show differences in auditory and visual information processing in the PPC. These results also demonstrate that neural signals from human PPC can be used to drive a dexterous cortical neuroprosthesis. SIGNIFICANCE STATEMENT This study shows for the first time hand-shape decoding from human PPC. Unlike nonhuman primate studies in which the visual stimuli are the objects to be grasped, the visually cued hand shapes that we use are independent of the stimuli. Furthermore, we can show that distinct neuronal populations are activated for the visual cue and the imagined hand shape. Additionally we found that auditory and visual stimuli that cue the same hand shape are processed differently in PPC. Early on in a trial, only the visual stimuli and not the auditory stimuli can be decoded. During the later stages of a trial, the motor imagery for a particular hand shape can be decoded for both modalities. PMID:26586832

  11. Distinct relationships of parietal and prefrontal cortices to evidence accumulation

    PubMed Central

    Hanks, Timothy; Kopec, Charles D.; Brunton, Bingni W.; Duan, Chunyu A.; Erlich, Jeffrey C.; Brody, Carlos D.

    2014-01-01

    Gradual accumulation of evidence is thought to be fundamental for decision-making, and its neural correlates have been found in multiple brain regions1–8. Here we develop a generalizable method to measure tuning curves that specify the relationship between neural responses and mentally-accumulated evidence, and apply it to distinguish the encoding of decision variables in posterior parietal cortex (PPC) and prefrontal cortex (frontal orienting fields, FOF). We recorded the firing rates of neurons in PPC and FOF from rats performing a perceptual decision-making task. Classical analyses uncovered correlates of accumulating evidence, similar to previous observations in primates and also similar across the two regions. However, tuning curve assays revealed that while the PPC encodes a graded value of the accumulating evidence, the FOF has a more categorical encoding that indicates, throughout the trial, the decision provisionally favored by the evidence accumulated so far. Contrary to current views3,5,7–9, this suggests that premotor activity in frontal cortex does not play a role in the accumulation process, but instead has a more categorical function, such as transforming accumulated evidence into a discrete choice. To causally probe the role of FOF activity, we optogenetically silenced it during different timepoints of the trial. Consistent with a role in committing to a categorical choice at the end of the evidence accumulation process, but not consistent with a role during the accumulation itself, a behavioral effect was observed only when FOF silencing occurred at the end of the perceptual stimulus. Our results place important constraints on the circuit logic of brain regions involved in decision-making. PMID:25600270

  12. Progressive limb ataxia following inferior olive lesions

    PubMed Central

    Horn, K M; Deep, A; Gibson, A R

    2013-01-01

    Cerebellar climbing fibres originate in the inferior olive (IO). Temporary IO inactivation produces movement deficits. Does permanent inactivation produce similar deficits and, if so, do they recover? The excitotoxin, kainic acid, was injected into the rostral IO of three cats. Behaviour was measured during reaching and locomotion. Two cats were injected during the reaching task. Within minutes, grasping became difficult and the trajectories of the reaches showed higher arcing than normally seen. During locomotion, both cats showed head and trunk deviation to the injected side, walking paths curved to the injected side, and the paws were lifted higher than normal. Limbs contralateral to the injections became rigid. Within 1 day, posture had normalized, locomotion was unsteady and high lifting of the paws had reversed to a tendency to drag the dorsum of the paws. Passive body movement produced vestibular signs. Over a few days, locomotion normalized and vestibular signs disappeared. Reach trajectories were normal but grasping deficits persisted. Over the first week, the amplitude of limb lift during reaching and locomotion began to increase. The increase continued over time and, after several months, limb movements became severely ataxic. The effects followed the somatotopy of the rostral IO: a loss of cells in medial rostral IO only affected the forelimb, whereas a loss of cells in medial and lateral IO affected both forelimb and hindlimb. Deficits produced by IO lesions involve multiple mechanisms; some recover rapidly, some appear stable, and some worsen over time. The nature of the progressive deficit suggests a gradual loss of Purkinje cell inhibition on cerebellar nuclear cells. PMID:23027819

  13. Cuboidal epithelium lining of the parietal layer of Bowman's capsule in Afghan pikas (Ochotona rufescens rufescens).

    PubMed

    Madarame, H; Kumagai, M; Motooka, N; Konno, S

    1991-01-01

    Kidneys of 64 Afghan pikas (Ochotona rufescens rufescens) were examined histologically. Seven of 21 males and two of 21 females over 6 months of age had a cuboidal epithelium lining of the parietal layer of Bowman's capsule.

  14. Fusion and Fission of Cognitive Functions in the Human Parietal Cortex

    PubMed Central

    Humphreys, Gina F.; Lambon Ralph, Matthew A.

    2015-01-01

    How is higher cognitive function organized in the human parietal cortex? A century of neuropsychology and 30 years of functional neuroimaging has implicated the parietal lobe in many different verbal and nonverbal cognitive domains. There is little clarity, however, on how these functions are organized, that is, where do these functions coalesce (implying a shared, underpinning neurocomputation) and where do they divide (indicating different underlying neural functions). Until now, there has been no multi-domain synthesis in order to reveal where there is fusion or fission of functions in the parietal cortex. This aim was achieved through a large-scale activation likelihood estimation (ALE) analysis of 386 studies (3952 activation peaks) covering 8 cognitive domains. A tripartite, domain-general neuroanatomical division and 5 principles of cognitive organization were established, and these are discussed with respect to a unified theory of parietal functional organization. PMID:25205661

  15. TMS in the parietal cortex: updating representations for attention and action.

    PubMed

    Rushworth, M F S; Taylor, P C J

    2006-01-01

    Transcranial magnetic stimulation (TMS) is one of the most recent techniques to have been used in investigations of the parietal cortex but already a number of studies have employed it as a tool in investigations of attentional and sensorimotor processes in the human parietal cortices. The high temporal resolution of TMS has proved to be a particular strength of the technique and the experiments have led to hypotheses about when circumscribed regions of parietal cortex are critical for specific attentional and sensorimotor processes. A consistent theme that runs through many reports is that of a critical contribution of parietal areas when attention or movements are re-directed and representations for attention or action must be updated.

  16. Involuntary hand levitation associated with parietal damage: another alien hand syndrome.

    PubMed

    Carrilho, P E; Caramelli, P; Cardoso, F; Barbosa, E R; Buchpiguel, C A; Nitrini, R

    2001-09-01

    The alien hand syndrome (AHS) usually consists of an autonomous motor activity perceived as an involuntary and purposeful movement, with a feeling of foreignness of the involved limb, commonly associated with a failure to recognise ownership of the limb in the absence of visual clues. It has been described in association to lesions of the frontal lobes and corpus callosum. However, parietal damage can promote an involuntary, but purposeless, hand levitation, which, sometimes, resembles AHS. In the present study, four patients (cortico-basal ganglionic degeneration - n=2; Alzheimer's disease - n=1 and parietal stroke - n=1) who developed alien hand motor behaviour and whose CT, MRI and/or SPECT have disclosed a major contralateral parietal damage or dysfunction are described. These results reinforce the idea that parietal lobe lesions may also play a role in some patients with purposeless involuntary limb levitation, which is different from the classic forms of AHS.

  17. Global increase in task-related fronto-parietal activity after focal frontal lobe lesion.

    PubMed

    Woolgar, Alexandra; Bor, Daniel; Duncan, John

    2013-09-01

    A critical question for neuropsychology is how complex brain networks react to damage. Here, we address this question for the well-known executive control or multiple-demand (MD) system, a fronto-parietal network showing increased activity with many different kinds of cognitive demand, including standard tests of fluid intelligence. Using fMRI, we ask how focal frontal lobe damage affects MD activity during a standard fluid intelligence task. Despite poor behavioral performance, frontal patients showed increased fronto-parietal activity relative to controls. The activation difference was not accounted for by difference in IQ. Moreover, rather than specific focus on perilesional or contralesional cortex, additional recruitment was distributed throughout the MD regions and surrounding cortex and included parietal MD regions distant from the injury. The data suggest that, following local frontal lobe damage, there is a global compensatory recruitment of an adaptive and integrated fronto-parietal network.

  18. The oft-neglected role of parietal EEG asymmetry and risk for major depressive disorder.

    PubMed

    Stewart, Jennifer L; Towers, David N; Coan, James A; Allen, John J B

    2011-01-01

    Relatively less right parietal activity may reflect reduced arousal and signify risk for major depressive disorder (MDD). Inconsistent findings with parietal electroencephalographic (EEG) asymmetry, however, suggest issues such as anxiety comorbidity and sex differences have yet to be resolved. Resting parietal EEG asymmetry was assessed in 306 individuals (31% male) with (n=143) and without (n=163) a DSM-IV diagnosis of lifetime MDD and no comorbid anxiety disorders. Past MDD+ women displayed relatively less right parietal activity than current MDD+ and MDD- women, replicating prior work. Recent caffeine intake, an index of arousal, moderated the relationship between depression and EEG asymmetry for women and men. Findings suggest that sex differences and arousal should be examined in studies of depression and regional brain activity.

  19. Force regulation is deficient in patients with parietal lesions: a system-analytic approach.

    PubMed

    Scholle, H C; Bradl, U; Hefter, H; Dohle, C; Freund, H J

    1998-06-01

    By means of a quantitative system-analytic investigation strategy, the postural motor control of the fingers was evaluated, to characterise the possible deficit of force regulation in patients with parietal lesions. In spite of a normal response to short torque pulses, the parietal-lesion patients had difficulties in returning to the preload level after the application of an additional step torque load to fingers II-IV of their left or right hands. The control offset (measured 500 ms after step torque application) was significantly larger in the patient group. This deficit in the investigated patients with parietal lesions to compensate for step torque loads was not due to a paresis, but rather resulted from a disturbance in the generation of a sufficient counterforce against the applied step torque within an adequate time window and motor pattern. This distinct force-regulation deficit was found in patients with left- and right-sided parietal lesions.

  20. [Combined resection of liver and inferior vena cava].

    PubMed

    Sherba, A E; Efimov, D Iu; Rummo, O O

    2014-01-01

    It was analyzed the results of treatment of 8 patients. Combined resection of liver and inferior vena cava was done in all cases. All resections of inferior vena cava were performed in combination with right-sided hemihepatectomy. Circular resection of inferior vena cava was done in 6 cases, tangential-in 2 cases. Allograft of donor inferior vena cava was used in 3 cases for reconstruction of inferior vena cava. Average duration of combined resection of liver and inferior vena cava was 675±189 min, average hemorrhage - 1800±1402 ml. The need for transfusion of packed red blood cells was 270±723 ml, the need for transfusion of fresh frozen plasma was 1105±636 ml. Post-resection liver failure according to criteria ISGLS developed in 3 patients (37.5%). Biliary complications such as biliary fistula and inconsistency of hepatico-jejunal anastomosis developed in 2 patients (25%). Hospital mortality was 12.5%. It is considered that resection of liver with inferior vena cava demands an experience in hepatobiliary surgery and/or liver transplantation. Surgeon must be ready to use total vascular isolation, hypothermic preservation and veno-venous bypass grafting. It allows to dilate an opportunity of resection liver surgery.

  1. Inferior Frontal Gyrus Activation Underlies the Perception of Emotions, While Precuneus Activation Underlies the Feeling of Emotions during Music Listening.

    PubMed

    Tabei, Ken-ichi

    2015-01-01

    While music triggers many physiological and psychological reactions, the underlying neural basis of perceived and experienced emotions during music listening remains poorly understood. Therefore, using functional magnetic resonance imaging (fMRI), I conducted a comparative study of the different brain areas involved in perceiving and feeling emotions during music listening. I measured fMRI signals while participants assessed the emotional expression of music (perceived emotion) and their emotional responses to music (felt emotion). I found that cortical areas including the prefrontal, auditory, cingulate, and posterior parietal cortices were consistently activated by the perceived and felt emotional tasks. Moreover, activity in the inferior frontal gyrus increased more during the perceived emotion task than during a passive listening task. In addition, the precuneus showed greater activity during the felt emotion task than during a passive listening task. The findings reveal that the bilateral inferior frontal gyri and the precuneus are important areas for the perception of the emotional content of music as well as for the emotional response evoked in the listener. Furthermore, I propose that the precuneus, a brain region associated with self-representation, might be involved in assessing emotional responses.

  2. Tactile apraxia: unimodal apractic disorder of tactile object exploration associated with parietal lobe lesions.

    PubMed

    Binkofski, F; Kunesch, E; Classen, J; Seitz, R J; Freund, H J

    2001-01-01

    Tactile apraxia is characterized by an isolated disturbance of hand movements for use of and interaction with an object (transitive movements) in the presence of preserved intransitive movements (movements without use of an object, for example repetitive movements or gestures). It is, however, still unclear whether motor and sensory abnormalities represent causal or associated features of tactile apraxia. To address this question, quantitative kinematic recordings of exploratory finger movements (transitive movements) and rapid alternating finger movements (intransitive movements) were studied in 20 healthy volunteers and 22 patients with focal lesions of the parietal, anterofrontal and motor cortex. The most severe deficits of manual object exploration were found in patients with parietal lesions, using the hand contralateral to the lesion. Patients with lesions of the anterior parietal lobe who exhibited prominent sensory deficits and astereognosia showed a decrease in frequency and regularity of exploratory finger movements and a marked increase in exploration space. Patients with posterior parietal lesions exhibiting severe astereognosia, apraxia and deficits in dexterity had a greater decrease in frequency and regularity of manipulative movements, but a less pronounced increase of exploration space than the patients with anterior parietal lesions. Although the patients with parietal lobe lesions could generate rapid alternating finger movements, the regularity of these movements was also impaired. In comparison, patients with frontal lobe lesions exhibited impaired contralesional manipulatory and rapid alternating finger movements but no sensory abnormalities or astereognosia. We conclude that tactile apraxia represents a deficit in the programming of exploratory finger movements mediated by the parietal lobe. The comparison with lesions of other regions participating in the cortical network for tactile exploration reveals that apraxia of exploratory movements

  3. Neural correlates of learning and working memory in the primate posterior parietal cortex.

    PubMed

    Rawley, Justin B; Constantinidis, Christos

    2009-02-01

    The posterior parietal cortex has been traditionally associated with coordinate transformations necessary for interaction with the environment and with visual-spatial attention. More recently, involvement of posterior parietal cortex in other cognitive functions such as working memory and task learning has become evident. Neurophysiological experiments in non-human primates and human imaging studies have revealed neural correlates of memory and learning at the single neuron and at the brain network level. During working memory, posterior parietal neurons continue to discharge and to represent stimuli that are no longer present. This activation resembles the responses of prefrontal neurons, although important differences have been identified in terms of the ability to resist stimulation by distracting stimuli, which is more evident in the prefrontal than the posterior parietal cortex. Posterior parietal neurons also become active during tasks that require the organization of information into larger structured elements and their activity is modulated according to learned context-dependent rules. Neural correlates of learning can be observed in the mean discharge rate and spectral power of neuronal spike trains after training to perform new task sets or rules. These findings demonstrate the importance of posterior parietal cortex in brain networks mediating working memory and learning.

  4. Task Context Overrules Object- and Category-Related Representational Content in the Human Parietal Cortex.

    PubMed

    Bracci, Stefania; Daniels, Nicky; Op de Beeck, Hans

    2017-01-01

    The dorsal, parietal visual stream is activated when seeing objects, but the exact nature of parietal object representations is still under discussion. Here we test 2 specific hypotheses. First, parietal cortex is biased to host some representations more than others, with a different bias compared with ventral areas. A prime example would be object action representations. Second, parietal cortex forms a general multiple-demand network with frontal areas, showing similar task effects and representational content compared with frontal areas. To differentiate between these hypotheses, we implemented a human neuroimaging study with a stimulus set that dissociates associated object action from object category while manipulating task context to be either action- or category-related. Representations in parietal as well as prefrontal areas represented task-relevant object properties (action representations in the action task), with no sign of the irrelevant object property (category representations in the action task). In contrast, irrelevant object properties were represented in ventral areas. These findings emphasize that human parietal cortex does not preferentially represent particular object properties irrespective of task, but together with frontal areas is part of a multiple-demand and content-rich cortical network representing task-relevant object properties.

  5. Eye-hand coordination during reaching. I. Anatomical relationships between parietal and frontal cortex.

    PubMed

    Marconi, B; Genovesio, A; Battaglia-Mayer, A; Ferraina, S; Squatrito, S; Molinari, M; Lacquaniti, F; Caminiti, R

    2001-06-01

    The anatomical and physiological substrata of eye-hand coordination during reaching were studied through combined anatomical and physiological techniques. The association connections of parietal areas V6A and PEc, and those of dorso-rostral (F7) and dorso-caudal (F2) premotor cortex were studied in monkeys, after physiological characterization of the parietal regions where retrograde tracers were injected. The results show that parieto-occipital area V6A is reciprocally connected with F7, and receives a smaller projection from F2. Local parietal projections to V6A arise from areas MIP and, to a lesser extent, 7m, PEa and PEC: On the contrary, parietal area PEc is strongly and reciprocally connected with the part of F2 located close to the pre-central dimple (pre-CD). Local parietal projections to PEc come from a distributed network, including PEa, MIP, PEci and, to a lesser extent, 7m, V6A, 7a and MST. Premotor area F7 receives parietal projections mainly from 7m and V6A, and local frontal projections mainly from F2. On the contrary, premotor area F2 in the pre-CD zone receives parietal inputs from PEc and, to a lesser extent, PEci, while in the peri-arcuate zone F2 receives parietal projections from PEa and MIP. Local frontal projections to F2 pre-CD mostly stem from F4, and, to a lesser extent, from F7 and F3, and CMAd; those addressed to peri-arcuate zone of F2 arise mainly from F5 and, to a lesser extent, from F7, F4, dorsal (CMAd) and ventral (CMAv) cingulate motor areas, pre-supplementary (F6) and supplementary (F3) motor areas. The distribution of association cells in both frontal and parietal cortex was characterized through a spectral analysis that revealed an arrangement of these cells in the form of bands, composed of cell clusters, or 'columns'. The reciprocal connections linking parietal and frontal cortex might explain the presence of visually related and eye-position signals in premotor cortex, as well as the influence of information about arm

  6. [Congenital anomalies of the inferior vena cava: role of imaging].

    PubMed

    Manfredi, R; Cotroneo, A R; Pirronti, T; Macis, G; Marano, P

    1995-10-01

    In recent years, clinics and radiology of congenital anomalies of the inferior vena cava have increased in importance in planning abdominal surgery, liver or kidney transplantation, or new interventional or diagnostic procedures such as the positioning of inferior vena cava filters to prevent pulmonary embolism, varicocel sclerotherapy and renal venous sampling. In the past, the radiologic assessment of these rare anomalies was performed only with angiography, which remains the most accurate diagnostic method. Today, besides angiography, less invasive examinations can be performed, e.g., US, CT and MRI, with MRA. In the last two years, 5 patients with inferior vena cava anomalies were examined: 3 had double inferior vena cava and 2 azygos continuation. All of them were submitted to US, CT, MRI and MRA and 3 patients underwent also angiography, two of them with double puncture. US can suggest the diagnosis but may be limited by technical factors and in the assessment of the whole inferior vena cava. Enhanced CT can depict anomaly extent, but uses contrast agents and ionizing radiations. Angiography better depicts craniocaudal spread and collateral networks but is an invasive procedure and sometimes needs a double puncture (double inferior vena cava). MRI, with MRA, yields the same information as the other modalities, but without contrast agents or ionizing radiations. The development of velocity encoded sequences will probably make this technique the method of choice in the study of inferior vena cava anomalies. Our study was aimed at reviewing the embryo-genesis of inferior vena cava anomalies and to assess the relative importance of different diagnostic procedures in the diagnosis and staging of these anomalies.

  7. Auditory scene analysis following unilateral inferior colliculus infarct.

    PubMed

    Champoux, François; Paiement, Philippe; Vannasing, Phetsamone; Mercier, Claude; Gagné, Jean-Pierre; Lepore, Franco; Lassonde, Maryse

    2007-11-19

    Event-related potentials in the form of mismatch negativity were recorded to investigate auditory scene analysis capabilities in a person with a very circumscribed haemorrhagic lesion at the level of the right inferior colliculus. The results provide the first objective evidence that processing at the level of the inferior colliculus plays an important role in human auditory frequency discrimination. Moreover, the electrophysiological data suggest that following this unilateral lesion, the auditory pathways fail to reorganize efficiently.

  8. Glucose utilization in the inferior cerebellar vermis and ocular myoclonus.

    PubMed

    Yakushiji, Y; Otsubo, R; Hayashi, T; Fukuchi, K; Yamada, N; Hasegawa, Y; Minematsu, K

    2006-07-11

    In a patient with symptomatic ocular myoclonus, the authors observed the regional cerebral metabolic rate of glucose use (rCMRGlu) before and after successful treatment with clonazepam. Even after the symptoms resolved, the rCMRGlu in the hypertrophic olive increased persistently, whereas that in the inferior cerebellar vermis contralateral to the hypertrophic olive decreased. The inferior cerebellar vermis, belonging to the vestibulocerebellar system, may be associated with the generation of symptomatic ocular myoclonus.

  9. Inferior ectopic pupil and typical ocular coloboma in RCS rats.

    PubMed

    Tsuji, Naho; Ozaki, Kiyokazu; Narama, Isao; Matsuura, Tetsuro

    2011-08-01

    Ocular coloboma is sometimes accompanied by corectopia in humans and therefore ectopic pupil may indicate ocular coloboma in experimental animals. The RCS strain of rats has a low incidence of microphthalmia. We found that inferior ectopic pupil is associated exclusively with small-sized eyes in this strain. The objective of the current study was to evaluate whether inferior ectopic pupil is associated with iridal coloboma and other types of ocular coloboma in RCS rats. Both eyes of RCS rats were examined clinically, and those with inferior ectopic pupils underwent morphologic and morphometric examinations. In a prenatal study, coronal serial sections of eyeballs from fetuses at gestational day 16.5 were examined by using light microscopy. Ectopic pupils in RCS rats were found exclusively in an inferior position, where the iris was shortened. Fundic examination revealed severe chorioretinal coloboma in all cases of inferior ectopic pupil. The morphologic characteristics closely resembled those of chorioretinal coloboma in humans. Histopathologic examination of primordia showed incomplete closure of the optic fissure in 4 eyeballs of RCS fetuses. Neither F(1) rats nor N(2) (progeny of RCS × BN matings) displayed any ocular anomalies, including ectopic pupils. The RCS strain is a suitable model for human ocular coloboma, and inferior ectopic pupil appears to be a strong indicator of ocular coloboma.

  10. Prestimulus frontal-parietal coherence predicts auditory detection performance in rats

    PubMed Central

    Herzog, Linnea; Salehi, Kia; Bohon, Kaitlin S.

    2014-01-01

    Electrophysiology in primates has implicated long-range neural coherence as a potential mechanism for enhancing sensory detection. To test whether local synchronization and long-range neural coherence support detection performance in rats, we recorded local field potentials (LFPs) in frontal and parietal cortex while rats performed an auditory detection task. We observed significantly elevated power at multiple low frequencies (<15 Hz) preceding the target beep when the animal failed to respond to the signal (misses), in both frontal and parietal cortex. In terms of long-range coherence, we observed significantly more frontal-parietal coherence in the beta band (15–30 Hz) before the signal on misses compared with hits. This effect persisted after regressing away linear trends in the coherence values during a session, showing that the excess frontal-parietal beta coherence prior to misses cannot be explained by slow motivational changes during a session. In addition, a trend toward higher low-frequency (<15 Hz) coherence prior to miss trials compared with hits became highly significant when we rereferenced the LFPs to the mean voltage on each recording array, suggesting that the results are specific to our frontal and parietal areas. These results do not support a role for long-range frontal-parietal coherence or local synchronization in facilitating the detection of external stimuli. Rather, they extend to long-range frontal-parietal coherence previous findings that correlate local synchronization of low-frequency (<15 Hz) oscillations with inattention to external stimuli and synchronization of beta rhythms (15–30 Hz) with voluntary or involuntary prolongation of the current cognitive or motor state. PMID:24572093

  11. Identification of ezrin as a target of gastrin in immature mouse gastric parietal cells.

    PubMed

    Pagliocca, Adelina; Hegyi, Peter; Venglovecz, Viktoria; Rackstraw, Stephen A; Khan, Zara; Burdyga, Galina; Wang, Timothy C; Dimaline, Rod; Varro, Andrea; Dockray, Graham J

    2008-11-01

    The gastric acid-secreting parietal cell exhibits profound morphological changes on stimulation. Studies in gastrin null (Gas-KO) mice indicate that maturation of parietal cell function depends on the hormone gastrin acting at the G-protein-coupled cholecystokinin 2 receptor. The relevant cellular mechanisms are unknown. The application of differential mRNA display to samples of the gastric corpus of wild-type (C57BL/6) and Gas-KO mice identified the cytoskeletal linker protein, ezrin, as a previously unsuspected target of gastrin. Gastrin administered in vivo or added to gastric glands in vitro increased ezrin abundance in Gas-KO parietal cells. In parietal cells of cultured gastric glands from wild-type mice treated with gastrin, histamine or carbachol, ezrin was localized to vesicular structures resembling secretory canaliculi. In contrast, in cultured parietal cells from Gas-KO mice, ezrin was typically distributed in the cytosol, and this did not change after incubation with gastrin, histamine or carbachol. However, priming with gastrin for approximately 24 h, either in vivo prior to cell culture or by addition to cultured gastric glands, induced the capacity for secretagogue-stimulated localization of ezrin to large vesicular structures in Gas-KO mice. Similarly, in a functional assay based on measurement of intracellular pH, cultured parietal cells from Gas-KO mice were refractory to gastrin unless primed. The priming effect of gastrin was not attributable to the paracrine mediator histamine, but was prevented by inhibitors of protein kinase C and transactivation of the epidermal growth factor receptor. We conclude that in gastrin null mice there is reduced ezrin expression and a defect in ezrin subcellular distribution in gastric parietal cells, and that both can be reversed by priming with gastrin.

  12. Reward-Based Decision Signals in Parietal Cortex Are Partially Embodied

    PubMed Central

    Snyder, Lawrence H.

    2015-01-01

    Recordings in the lateral intraparietal area (LIP) reveal that parietal cortex encodes variables related to spatial decision-making, the selection of desirable targets in space. It has been unclear whether parietal cortex is involved in spatial decision-making in general, or whether specific parietal compartments subserve decisions made using specific actions. To test this, we engaged monkeys (Macaca mulatta) in a reward-based decision task in which they selected a target based on its desirability. The animals' choice behavior in this task followed the molar matching law, and in each trial was governed by the desirability of the choice targets. Critically, animals were instructed to make the choice using one of two actions: eye movements (saccades) and arm movements (reaches). We recorded the discharge activity of neurons in area LIP and the parietal reach region (PRR) of the parietal cortex. In line with previous studies, we found that both LIP and PRR encode a reward-based decision variable, the target desirability. Crucially, the target desirability was encoded in LIP at least twice as strongly when choices were made using saccades compared with reaches. In contrast, PRR encoded target desirability only for reaches and not for saccades. These data suggest that decisions can evolve in dedicated parietal circuits in the context of specific actions. This finding supports the hypothesis of an intentional representation of developing decisions in parietal cortex. Furthermore, the close link between the cognitive (decision-related) and bodily (action-related) processes presents a neural contribution to the theories of embodied cognition. PMID:25810518

  13. Anterior transposition of the inferior oblique muscle as the initial treatment of a snapped inferior rectus muscle.

    PubMed

    Aguirre-Aquino, B I; Riemann, C D; Lewis, H; Traboulsi, E I

    2001-02-01

    Snapping or tearing of an extraocular muscle refers to its rupture across its width, usually at the junction between muscle and tendon several millimeters behind the insertion. Tearing occurs during strabismus or retinal reattachment surgery, or after trauma. If the proximal end of the muscle cannot be located, transposition procedures are necessary to achieve ocular realignment. These surgical procedures carry the risk of anterior segment ischemia, especially in the elderly. Anterior transposition of the inferior oblique muscle has been used for the treatment of inferior oblique overaction, especially in the presence of a dissociated vertical deviation, and in patients with fourth nerve palsy. We transposed the inferior oblique muscle insertion in a 73-year-old woman with a snapped inferior rectus muscle.

  14. Behaviorally Relevant Abstract Object Identity Representation in the Human Parietal Cortex

    PubMed Central

    Jeong, Su Keun

    2016-01-01

    The representation of object identity is fundamental to human vision. Using fMRI and multivoxel pattern analysis, here we report the representation of highly abstract object identity information in human parietal cortex. Specifically, in superior intraparietal sulcus (IPS), a region previously shown to track visual short-term memory capacity, we found object identity representations for famous faces varying freely in viewpoint, hairstyle, facial expression, and age; and for well known cars embedded in different scenes, and shown from different viewpoints and sizes. Critically, these parietal identity representations were behaviorally relevant as they closely tracked the perceived face-identity similarity obtained in a behavioral task. Meanwhile, the task-activated regions in prefrontal and parietal cortices (excluding superior IPS) did not exhibit such abstract object identity representations. Unlike previous studies, we also failed to observe identity representations in posterior ventral and lateral visual object-processing regions, likely due to the greater amount of identity abstraction demanded by our stimulus manipulation here. Our MRI slice coverage precluded us from examining identity representation in anterior temporal lobe, a likely region for the computing of identity information in the ventral region. Overall, we show that human parietal cortex, part of the dorsal visual processing pathway, is capable of holding abstract and complex visual representations that are behaviorally relevant. These results argue against a “content-poor” view of the role of parietal cortex in attention. Instead, the human parietal cortex seems to be “content rich” and capable of directly participating in goal-driven visual information representation in the brain. SIGNIFICANCE STATEMENT The representation of object identity (including faces) is fundamental to human vision and shapes how we interact with the world. Although object representation has traditionally been

  15. Frontal and parietal lobe involvement in the processing of pretence and intention.

    PubMed

    Chiavarino, Claudia; Apperly, Ian A; Humphreys, Glyn W

    2009-09-01

    We assessed whether different processes might be at play during pretence understanding by examining breakdowns of performance in participants with acquired brain damage. In Experiment 1 patients with frontal or parietal lesions and neurologically intact adults were asked to categorize videos of pretend and real actions. In Experiment 2 participants saw three types of videos: real intentional actions, real accidental actions, and pretend actions. In one session they judged whether the actions they saw were intentional or accidental, and in a second session they judged whether the actions were real or pretend. Parietal patients had particular difficulties in the identification of pretend actions, and both parietal and frontal patients were more impaired than controls in understanding the intentional nature of pretence. Analyses of individual patients' performance revealed that parietal lesions, and in particular lesions to the temporo-parietal junction, impaired the ability to discriminate pretend from real actions. However, this did not necessarily affect the discrimination of intentional from unintentional actions, which instead may be independently disrupted by damage to frontal areas. Moreover, spared ability to discriminate pretend actions from real actions, and intentional actions from accidental actions, did not grant a full conceptual understanding of the intentional nature of pretence. The implications for pretence understanding are discussed.

  16. Early math achievement and functional connectivity in the fronto-parietal network.

    PubMed

    Emerson, Robert W; Cantlon, Jessica F

    2012-02-15

    In this study we test the hypothesis that the functional connectivity of the frontal and parietal regions that children recruit during a basic numerical task (matching Arabic numerals to arrays of dots) is predictive of their math test scores (TEMA-3; Ginsburg, 2003). Specifically, we tested 4-11-year-old children on a matching task during fMRI to localize a fronto-parietal network that responds more strongly during numerical matching than matching faces, words, or shapes. We then tested the functional connectivity between those regions during an independent task: natural viewing of an educational video that included math topics. Using this novel natural viewing method, we found that the connectivity between frontal and parietal regions during task-independent free-viewing of educational material is correlated with children's basic number matching ability, as well as their scores on the standardized test of mathematical ability (the TEMA). The correlation between children's mathematics scores and fronto-parietal connectivity is math-specific in the sense that it is independent of children's verbal IQ scores. Moreover, a control network, selective for faces, showed no correlation with mathematics performance. Finally, brain regions that correlate with subjects' overall response times in the matching task do not account for our number- and math-related effects. We suggest that the functional intersection of number-related frontal and parietal regions is math-specific.

  17. Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination

    PubMed Central

    Muthukumaraswamy, Suresh D.; Hibbs, Carina S.; Shapiro, Kimron L.; Bracewell, R. Martyn; Singh, Krish D.; Linden, David E. J.

    2011-01-01

    The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80–100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination. PMID:21940605

  18. Early Math Achievement and Functional Connectivity in the Fronto-Parietal Network

    PubMed Central

    Emerson, Robert W.; Cantlon, Jessica F.

    2011-01-01

    In this study we test the hypothesis that the functional connectivity of the frontal and parietal regions that children recruit during a basic numerical task (matching Arabic numerals to arrays of dots) is predictive of their math test scores (TEMA-3; Ginsburg 2003). Specifically, we tested 4- to 11-year-old children on a matching task during fMRI to localize a fronto-parietal network that responds more strongly during numerical matching than matching faces, words, or shapes. We then tested the functional connectivity between those regions during an independent task: natural viewing of an educational video that included math topics. Using this novel natural viewing method, we found that the connectivity between frontal and parietal regions during task-independent free-viewing of educational material is correlated with children's basic number matching ability, as well as their scores on the standardized test of mathematical ability (the TEMA). The correlation between children's mathematics scores and fronto-parietal connectivity is math-specific in the sense that it is independent of children's verbal IQ scores. Moreover, a control network, selective for faces, showed no correlation with mathematics performance. Finally, brain regions that correlate with subjects’ overall response times in the matching task do not account for our number- and math-related effects. We suggest that the functional intersection of number-related frontal and parietal regions is math-specific. PMID:22682903

  19. Phosphene-guided transcranial magnetic stimulation of occipital but not parietal cortex suppresses stimulus visibility.

    PubMed

    Tapia, Evelina; Mazzi, Chiara; Savazzi, Silvia; Beck, Diane M

    2014-06-01

    Transcranial magnetic stimulation (TMS) applied over the occipital lobe approximately 100 ms after the onset of a stimulus decreases its visibility if it appears in the location of the phosphene. Because phosphenes can also be elicited by stimulation of the parietal regions, we asked if the same procedure that is used to reduce visibility of stimuli with occipital TMS will lead to decreased stimulus visibility when TMS is applied to parietal regions. TMS was randomly applied at 0-130 ms after the onset of the stimulus in steps of 10 ms in occipital and parietal regions. Participants responded to the orientation of the line stimulus and rated its visibility. We replicate previous reports of phosphenes from both occipital and parietal TMS. As previously reported, we also observed visual suppression around the classical 100 ms window both in the objective line orientation and subjective visibility responses with occipital TMS. Parietal stimulation, on the other hand, did not consistently reduce stimulus visibility in any time window.

  20. Parietal rTMS distorts the mental number line: simulating 'spatial' neglect in healthy subjects.

    PubMed

    Göbel, Silke M; Calabria, Marco; Farnè, Alessandro; Rossetti, Yves

    2006-01-01

    Patients with left-sided visuospatial neglect, typically after damage to the right parietal lobe, show a systematic bias towards larger numbers when asked to bisect a numerical interval. This has been taken as further evidence for a spatial representation of numbers, perhaps akin to a mental number line with smaller numbers represented to the left and larger numbers to the right. Previously, contralateral neglect-like symptoms in physical line bisection have been induced in healthy subjects with repetitive transcranial magnetic stimulation (rTMS) over right posterior parietal lobe. Here we used rTMS over parietal and occipital sites in healthy subjects to investigate spatial representations in a number bisection task. Subjects were asked to name the midpoint of numerical intervals without calculating. On control trials subjects' behaviour was similar to performance reported in physical line bisection experiments. Subjects underestimated the midpoint of the numerical interval. Repetitive transcranial magnetic stimulation produced representational neglect-like symptoms in number bisection when applied over right posterior parietal cortex (right PPC). Repetitive TMS over right PPC shifted the perceived midpoint of the numerical interval significantly to the right while occipital TMS had no effect on bisection performance. Our study therefore provides further evidence that subjects use spatial representations, perhaps akin to a mental number line, in basic numerical processing tasks. Furthermore, we showed that the right posterior parietal cortex is crucially involved in spatial representation of numbers.

  1. Feature integration in visual working memory: parietal gamma activity is related to cognitive coordination.

    PubMed

    Morgan, Helen M; Muthukumaraswamy, Suresh D; Hibbs, Carina S; Shapiro, Kimron L; Bracewell, R Martyn; Singh, Krish D; Linden, David E J

    2011-12-01

    The mechanism by which distinct subprocesses in the brain are coordinated is a central conundrum of systems neuroscience. The parietal lobe is thought to play a key role in visual feature integration, and oscillatory activity in the gamma frequency range has been associated with perception of coherent objects and other tasks requiring neural coordination. Here, we examined the neural correlates of integrating mental representations in working memory and hypothesized that parietal gamma activity would be related to the success of cognitive coordination. Working memory is a classic example of a cognitive operation that requires the coordinated processing of different types of information and the contribution of multiple cognitive domains. Using magnetoencephalography (MEG), we report parietal activity in the high gamma (80-100 Hz) range during manipulation of visual and spatial information (colors and angles) in working memory. This parietal gamma activity was significantly higher during manipulation of visual-spatial conjunctions compared with single features. Furthermore, gamma activity correlated with successful performance during the conjunction task but not during the component tasks. Cortical gamma activity in parietal cortex may therefore play a role in cognitive coordination.

  2. Interhemispheric visuo-motor integration in humans: the role of the superior parietal cortex.

    PubMed

    Iacoboni, Marco; Zaidel, Eran

    2004-01-01

    We used event-related functional magnetic resonance imaging (fMRI) to investigate the neural correlates of basic interhemispheric visuo-motor integration. In a simple reaction time task, subjects responded to lateralized left and right light flashes with unimanual left and right hand responses. Typically, reaction times are faster for uncrossed responses (that is, visual stimulus and response hand on the same side) than for crossed responses (that is, visual stimulus and response hand on opposite sides). The chronometric difference between crossed and uncrossed responses is called crossed-uncrossed difference (CUD) and it is typically taken to represent a behavioral estimate of interhemispheric transfer time. The fMRI results obtained in normal right-handers show that the crossed conditions yielded greater activity, compared to the uncrossed conditions, in bilateral prefrontal, bilateral dorsal premotor, and right superior parietal areas. These results suggest that multiple transfers between the hemispheres occur in parallel at the functional levels of sensory-motor integration (posterior parietal), decision-making (prefrontal) and preparation of motor response (premotor). To test the behavioral significance of these multiple transfers, we correlated the individual CUDs with the difference in signal intensity between crossed and uncrossed responses in the prefrontal, dorsal premotor, and right superior parietal activated areas. The analyses demonstrated a strong correlation between the CUD and signal intensity difference between crossed and uncrossed responses in the right superior parietal cortex. These data suggest a critical role of the superior parietal cortex in interhemispheric visuo-motor integration.

  3. The human parietal operculum. II. Stereotaxic maps and correlation with functional imaging results.

    PubMed

    Eickhoff, Simon B; Amunts, Katrin; Mohlberg, Hartmut; Zilles, Karl

    2006-02-01

    In this study we describe the localization of the cytoarchitectonic subdivisions of the human parietal operculum in stereotaxic space and relate these anatomically defined cortical areas to the location of the functionally defined secondary somatosensory cortex (SII cortex) using a meta-analysis of functional imaging results. The human parietal operculum consists of four distinct cytoarchitectonic areas (OP 1-4) as shown in the preceding publication. The 10 cytoarchitectonically examined brains were 3-D-reconstructed and spatially normalized to the T1-weighted single-subject template of the Montreal Neurological Institute (MNI). A probabilistic map was calculated for each area in this standard stereotaxic space. A cytoarchitectonic summary map of the four cortical areas on the human parietal operculum which combines these probabilistic maps was subsequently computed for the comparison with a meta-analysis of functional locations of SII. The meta-analysis used the results from 57 fMRI and PET studies and allowed the comparison of the functionally defined SII region to the cytoarchitectonic map of the parietal operculum. The functional localization of SII showed a good match to the cytoarchitectonically defined region. Therefore the cytoarchitectonic maps of OP 1-4 of the human parietal operculum can be interpreted as an anatomical correlate of the (functionally defined) human SII region. Our results also suggest that the SII foci reported in functional imaging studies may actually reflect activations in either of its architectonic subregions.

  4. Modelling dynamic fronto-parietal behaviour during minimally invasive surgery--a Markovian trip distribution approach.

    PubMed

    Leff, Daniel Richard; Orihuela-Espina, Felipe; Leong, Julian; Darzi, Ara; Yang, Guang-Zhong

    2008-01-01

    Learning to perform Minimally Invasive Surgery (MIS) requires considerable attention, concentration and spatial ability. Theoretically, this leads to activation in executive control (prefrontal) and visuospatial (parietal) centres of the brain. A novel approach is presented in this paper for analysing the flow of fronto-parietal haemodynamic behaviour and the associated variability between subjects. Serially acquired functional Near Infrared Spectroscopy (fNIRS) data from fourteen laparoscopic novices at different stages of learning is projected into a low-dimensional 'geospace', where sequentially acquired data is mapped to different locations. A trip distribution matrix based on consecutive directed trips between locations in the geospace reveals confluent fronto-parietal haemodynamic changes and a gravity model is applied to populate this matrix. To model global convergence in haemodynamic behaviour, a Markov chain is constructed and by comparing sequential haemodynamic distributions to the Markov's stationary distribution, inter-subject variability in learning an MIS task can be identified.

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

    PubMed

    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.

  6. The Predictive Nature of Pseudoneglect for Visual Neglect: Evidence from Parietal Theta Burst Stimulation

    PubMed Central

    Varnava, Alice; Dervinis, Martynas; Chambers, Christopher D.

    2013-01-01

    Following parietal damage most patients with visual neglect bisect horizontal lines significantly away from the true centre. Neurologically intact individuals also misbisect lines; a phenomenon referred to as ‘pseudoneglect’. In this study we examined the relationship between neglect and pseudoneglect by testing how patterns of pre-existing visuospatial asymmetry predict asymmetry caused by parietal interference. Twenty-four participants completed line bisection and Landmark tasks before receiving continuous theta burst stimulation to the left or right angular gyrus. Results showed that a pre-existing pattern of left pseudoneglect (i.e. right bias), but not right pseudoneglect, predicts left neglect-like behaviour during line bisection following right parietal cTBS. This correlation is consistent with the view that neglect and pseudoneglect arise via a common or linked neural mechanism. PMID:23823975

  7. Only coherent spiking in posterior parietal cortex coordinates looking and reaching.

    PubMed

    Dean, Heather L; Hagan, Maureen A; Pesaran, Bijan

    2012-02-23

    Here, we report that temporally patterned, coherent spiking activity in the posterior parietal cortex (PPC) coordinates the timing of looking and reaching. Using a spike-field approach, we identify a population of parietal area LIP neurons that fire spikes coherently with 15 Hz beta-frequency LFP activity. The firing rate of coherently active neurons predicts the reaction times (RTs) of coordinated reach-saccade movements but not of saccades when made alone. Area LIP neurons that do not fire coherently do not predict RT of either movement type. Similar beta-band LFP activity is present in the parietal reach region but not nearby visual area V3d. This suggests that coherent spiking activity in PPC can control reaches and saccades together. We propose that the neural mechanism of coordination involves a shared representation that acts to slow or speed movements together.

  8. Physiological implications of the abnormal absence of the parietal foramen in a late Permian cynodont (Therapsida)

    NASA Astrophysics Data System (ADS)

    Benoit, Julien; Abdala, Fernando; Van den Brandt, Marc J.; Manger, Paul R.; Rubidge, Bruce S.

    2015-12-01

    The third eye (pineal eye), an organ responsible for regulating exposure to sunlight in extant ectotherms, is located in an opening on the dorsal surface of the skull, the parietal foramen. The parietal foramen is absent in extant mammals but often observed in basal therapsids, the stem-group to true mammals. Here, we report the absence of the parietal foramen in a specimen of Cynosaurus suppostus, a Late Permian cynodont from South Africa (SA). Comparison with Procynosuchus delaharpeae, a contemporaneous non-mammalian cynodont from SA, demonstrates that the absence of this foramen is an abnormal condition for such a basal species. Because seasonality was marked during the Late Permian in SA, it is proposed that the third eye was functionally redundant in Cynosaurus, possibly due to the acquisition of better thermoregulation or the evolution of specialized cells in the lateral eyes to compensate for the role of the third eye.

  9. Fractionation of parietal function in bistable perception probed with concurrent TMS-EEG

    PubMed Central

    Schauer, Georg; Chang, Acer; Schwartzman, David; Rae, Charlotte L.; Iriye, Heather; Seth, Anil K.; Kanai, Ryota

    2016-01-01

    When visual input has conflicting interpretations, conscious perception can alternate spontaneously between these possible interpretations. This is called bistable perception. Previous neuroimaging studies have indicated the involvement of two right parietal areas in resolving perceptual ambiguity (ant-SPLr and post-SPLr). Transcranial magnetic stimulation (TMS) studies that selectively interfered with the normal function of these regions suggest that they play opposing roles in this type of perceptual switch. In the present study, we investigated this fractionation of parietal function by use of combined TMS with electroencephalography (EEG). Specifically, while participants viewed either a bistable stimulus, a replay stimulus, or resting-state fixation, we applied single pulse TMS to either location independently while simultaneously recording EEG. Combined with participant’s individual structural magnetic resonance imaging (MRI) scans, this dataset allows for complex analyses of the effect of TMS on neural time series data, which may further elucidate the causal role of the parietal cortex in ambiguous perception. PMID:27529410

  10. Fractionation of parietal function in bistable perception probed with concurrent TMS-EEG.

    PubMed

    Schauer, Georg; Chang, Acer; Schwartzman, David; Rae, Charlotte L; Iriye, Heather; Seth, Anil K; Kanai, Ryota

    2016-08-16

    When visual input has conflicting interpretations, conscious perception can alternate spontaneously between these possible interpretations. This is called bistable perception. Previous neuroimaging studies have indicated the involvement of two right parietal areas in resolving perceptual ambiguity (ant-SPLr and post-SPLr). Transcranial magnetic stimulation (TMS) studies that selectively interfered with the normal function of these regions suggest that they play opposing roles in this type of perceptual switch. In the present study, we investigated this fractionation of parietal function by use of combined TMS with electroencephalography (EEG). Specifically, while participants viewed either a bistable stimulus, a replay stimulus, or resting-state fixation, we applied single pulse TMS to either location independently while simultaneously recording EEG. Combined with participant's individual structural magnetic resonance imaging (MRI) scans, this dataset allows for complex analyses of the effect of TMS on neural time series data, which may further elucidate the causal role of the parietal cortex in ambiguous perception.

  11. Inferior oblique muscle paresis as a sign of myasthenia gravis.

    PubMed

    Almog, Yehoshua; Ben-David, Merav; Nemet, Arie Y

    2016-03-01

    Myasthenia gravis may affect any of the six extra-ocular muscles, masquerading as any type of ocular motor pathology. The frequency of involvement of each muscle is not well established in the medical literature. This study was designed to determine whether a specific muscle or combination of muscles tends to be predominantly affected. This retrospective review included 30 patients with a clinical diagnosis of myasthenia gravis who had extra-ocular muscle involvement with diplopia at presentation. The diagnosis was confirmed by at least one of the following tests: Tensilon test, acetylcholine receptor antibodies, thymoma on chest CT scan, or suggestive electromyography. Frequency of involvement of each muscle in this cohort was inferior oblique 19 (63.3%), lateral rectus nine (30%), superior rectus four (13.3%), inferior rectus six (20%), medial rectus four (13.3%), and superior oblique three (10%). The inferior oblique was involved more often than any other muscle (p<0.01). Eighteen (60%) patients had ptosis, six (20%) of whom had bilateral ptosis. Diagnosing myasthenia gravis can be difficult, because the disease may mimic every pupil-sparing pattern of ocular misalignment. In addition diplopia caused by paresis of the inferior oblique muscle is rarely encountered (other than as a part of oculomotor nerve palsy). Hence, when a patient presents with vertical diplopia resulting from an isolated inferior oblique palsy, myasthenic etiology should be highly suspected.

  12. The effects of inferior olive lesion on strychnine seizure

    SciTech Connect

    Anderson, M.C.; Chung, E.Y.; Van Woert, M.H. )

    1990-10-01

    Bilateral inferior olive lesions, produced by systemic administration of the neurotoxin 3-acetylpyridine (3AP) produce a proconvulsant state specific for strychnine-induced seizures and myoclonus. We have proposed that these phenomena are mediated through increased excitation of cerebellar Purkinje cells, through activation of glutamate receptors, in response to climbing fiber deafferentation. An increase in quisqualic acid (QA)-displaceable ({sup 3}H)AMPA ((RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid) binding in cerebella from inferior olive-lesioned rats was observed, but no difference in ({sup 3}H)AMPA binding displaced by glutamate, kainic acid (KA) or glutamate diethylester (GDEE) was seen. The excitatory amino acid antagonists GDEE and MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclo-hepten-5,10 imine) were tested as anticonvulsants for strychnine-induced seizures in 3AP inferior olive-lesioned and control rats. Neither drug effected seizures in control rats, however, both GDEE and MK-801 produced a leftward shift in the strychnine-seizure dose-response curve in 3AP inferior olive-lesioned rats. GDEE also inhibited strychnine-induced myoclonus in the lesioned group, while MK-801 had no effect on myoclonus. The decreased threshold for strychnine-induced seizures and myoclonus in the 3AP-inferior olive-lesioned rats may be due to an increase in glutamate receptors as suggested by the ({sup 3}H)AMPA binding data.

  13. Anterior ST segment depression in acute inferior myocardial infarction as a marker of greater inferior, apical, and posterolateral damage

    SciTech Connect

    Ruddy, T.D.; Yasuda, T.; Gold, H.K.; Leinbach, R.C.; Newell, J.B.; McKusick, K.A.; Boucher, C.A.; Strauss, H.W.

    1986-12-01

    The clinical significance of anterior precordial ST segment depression during acute inferior myocardial infarction was evaluated in 67 consecutive patients early after onset of symptoms with gated blood pool scans, thallium-201 perfusion images, and 12-lead ECGs. Patients with anterior ST depression (n = 33) had depressed mean values for left ventricular ejection fraction (54 +/- 2% (mean +/- S.E.M.) vs 59 +/- 2%; p = 0.02), cardiac index (3.1 +/- 0.2 vs 3.6 +/- 0.2 L/m2; p = 0.03), and ratio of systolic blood pressure to end-systolic volume (2.0 +/- 0.1 vs 2.5 +/- 0.3 mm Hg/ml; p = 0.04) compared to patients with no anterior ST depression (n = 34). Patients with anterior ST depression had (1) lower mean wall motion values for the inferior, apical, and inferior posterolateral segments (p less than 0.05) and (2) greater reductions in thallium-201 uptake in the inferior and posterolateral regions (p less than 0.05). However, anterior and septal (1) wall motion and (2) thallium-201 uptake were similar in patients with and without ST depression. Thus, anterior precordial ST segment depression in patients with acute inferior wall myocardial infarction represents more than a reciprocal electrical phenomenon. It identifies patients with more severe wall motion impairment and greater hypoperfusion of the inferior and adjacent segments. The poorer global left ventricular function in these patients is a result of more extensive inferior infarction and not of remote septal or anterior injury.

  14. Vacuolar-type H+-ATPase-mediated proton transport in the rat parietal cell.

    PubMed

    Kopic, Sascha; Wagner, Maximilian E H; Griessenauer, Christoph; Socrates, Thenral; Ritter, Markus; Geibel, John P

    2012-03-01

    The vacuolar-type H-ATPase (V-ATPase) plays an important role in the active acidification of intracellular organelles. In certain specialized cells, such as the renal intercalated cell, apical V-ATPase can also function as a proton secretion pathway. In the parietal cells of the stomach, it has been thought that acid secretion is controlled solely via the H,K-ATPase. However, recent observations suggest that functional V-ATPase is necessary for acid secretion to take place. This study aimed to investigate and characterize the role of V-ATPase in parietal cell proton transport. Individual rat gastric glands were incubated with the pH-sensitive dye (BCECF) to monitor changes in intracellular pH in real time. Parietal cell V-ATPase activity was measured by quantifying the rate of intracellular alkalinization (ΔpH/minute) following an acid load, while excluding the contribution of non-V-ATPase proton transport mechanisms through pharmacological inhibition or ion substitution. Expression of V-ATPase was confirmed by immunohistochemistry. We observed concanamycin A-sensitive V-ATPase activity in rat parietal cells following intracellular acidification and H,K-ATPase inhibition. Furthermore, V-ATPase-mediated proton transport could be abolished by inhibiting trafficking mechanisms with paclitaxel and by stimulating H,K-ATPase with acid secretagogues. Our results propose that parietal cells contain a functional V-ATPase that can be mobilized using a microtubule network. V-ATPase may function as an auxiliary acid secretion or proton-buffering pathway in parietal cells, which is inactive during H,K-ATPase activity. Our findings may have important implications for patients experiencing acid breakthrough under proton pump inhibitor therapy.

  15. Neuronal activity in the parietal cortex of EL and DDY mice.

    PubMed

    Suzuki, Jiro; Ozawa, Nobuyuki; Murashima, Yoshiya L; Shinba, Tosikazu; Yoshii, Mitsunobu

    2012-06-15

    To elucidate the mechanism of epileptogenesis, seizures were investigated in the EL mouse, which is an excellent model for epilepsy. In these mice, epileptic seizures initiate in the parietal cortex, where markers of GABA-mediated inhibition are reduced compared with the parietal cortex of DDY mice (the parent strain). This is the first report on units of neuronal activity in the parietal cortex of EL and DDY mice (14 each) using an extracellular microelectrode in vivo under moderate pentobarbital anesthesia. The parietal cortex neurons of the EL mice were less active at rest than those of the DDY mice, but they responded more actively to proprioceptive afferent input from muscle stimulation than the DDY neurons. Three types of spontaneous firing were classified in both EL and DDY cortical neurons: periodically firing, Type A; continuously firing, Type B; and random firing, Type C. The proportions of these three types of neurons were almost the same in the EL mice as in the DDY mice. The peak frequency of the periodical cycle of Type A neurons in the EL mice (375 ms) was longer than that of the Type A neurons in the DDY mice (225 ms). Four patterns of responses to stimulation were observed in the parietal cortex neurons. More excitatory patterns were observed in the EL mice than in the DDY mice. The trans-laminar distribution of cells with different response patterns was also different between the EL and DDY mice. These characteristics of parietal cortex neurons may help determine the seizure susceptibility or ictogenesis in EL mice because the mechanisms underlying these patterns could provide the basis for hypersynchronized discharges in epileptic seizures.

  16. Primary culture of secretagogue-responsive parietal cells from rabbit gastric mucosa

    SciTech Connect

    Chew, C.S.; Ljungstroem, M.S.; Smolka, A.; Brown, M.R.

    1989-01-01

    A new procedure for isolation and primary culture of gastric parietal cells is described. Parietal cells from rabbit gastric mucosa are enriched to greater than 95% purity by combining a Nycodenz gradient separation with centrifugal elutriation. Cells are plated on the basement membrane matrix, Matrigel, and maintained in culture for at least 1 wk. Parietal cells cultured in this manner remain differentiated, cross-react with monoclonal H+-K+-ATPase antibodies, and respond to histamine, gastrin, and cholinergic stimulation with increased acid production as measured by accumulation of the weak base, (/sup 14/C)aminopyrine. When stimulated, cultured cells undergo ultrastructural changes in which intracellular canaliculi expand and numerous microvilli are observed. These ultrastructural changes are similar to those previously found to occur in vivo and in acutely isolated parietal cells. Morphological transformations in living cells can also be observed with differential interference contrast optics in the light microscope. After histamine stimulation, intracellular canaliculi gradually expand to form large vacuolar spaces. When the H2 receptor antagonist, cimetidine, is added to histamine-stimulated cells, these vacuoles gradually disappear. The ability to maintain hormonally responsive parietal cells in primary culture should make it possible to study direct, long-term effects of a variety of agonists and antagonists on parietal cell secretory-related activity. These cultured cells should also prove to be useful for the study of calcium transients, ion fluxes, and intracellular pH as related to acid secretion in single cells, particularly since morphological transformations can be used to monitor physiological responses at the same time within the same cell.

  17. Dissociating estimation from comparison and response eliminates parietal involvement in sequential numerosity perception.

    PubMed

    Cavdaroglu, Seda; Katz, Curren; Knops, André

    2015-08-01

    It has been widely debated whether the parietal cortex stores an abstract representation of numerosity that is activated for Arabic digits as well as for non-symbolic stimuli in a sensory modality independent fashion. Some studies suggest that numerical information in time-invariant (simultaneous) symbolic and non-symbolic visual stimuli is represented in the parietal cortex. In humans, whether the same representation is activated for time-variant (sequential) stimuli and for stimuli coming from different modalities has not been determined. To investigate this idea, we measured the brain activation of healthy adults performing estimation and/or comparison of sequential visual (series of dots) and auditory (series of beeps) numerosities. Our experimental design allowed us to separate numerosity estimation from comparison and response related factors. The BOLD response in the parietal cortex increased only when participants were engaged in the comparison of two consecutive numerosities that required a response. Using multivariate pattern analysis we trained a classifier to decode numerosity in various regions of interest (ROI). We failed to find any parietal ROI where the classifier could decode numerosities during the estimation phase. Rather, when participants were not engaged in comparison we were able to decode numerosity in an auditory cortex ROI for auditory stimuli and in a visual cortex ROI for visual stimuli. On the other hand, during the response period the classifier successfully decoded numerosity information in a parietal ROI for both visual and auditory numerosities. These results were further confirmed by support vector regression. In sum, our study does not support the involvement of the parietal cortex during estimation of sequential numerosity in the absence of an active task with a response requirement.

  18. [Responses of neurons of the associative parietal cortex during acute extinction restoration of a conditioned reflex].

    PubMed

    Prikhodchenko, N N

    1977-01-01

    The dynamics of spike neuronal activity in the parietal associative cortex was studied in the course of acute extinction and restoration of a conditioned reflex. Certain similarities have been found in neuronal firing during the reorganization of behavioral acts (transient processes in neuronal activity, general types of neuronal responses, etc.) The data obtained suggest the involvement of neurones of the parietal associative cortex in the processes related to the reorganization of behavioral acts, and the existence of common mechanisms of search for an optimal regime of neuronal assemblies functioning in different types of conditioned activity.

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

    PubMed

    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.

  20. Altered prefronto-striato-parietal network response to mental rotation in HIV.

    PubMed

    Schweinsburg, Brian C; Scott, J Cobb; Schweinsburg, Alecia Dager; Jacobus, Joanna; Theilmann, Rebecca J; Frank, Larry R; Weber, Erica; Grant, Igor; Woods, Steven Paul

    2012-02-01

    The present study used functional magnetic resonance imaging to examine the neural substrates of mental rotation in 11 individuals with HIV infection and 13 demographically similar HIV seronegative volunteers. Individuals with HIV showed increased brain response to mental rotation in prefrontal and posterior parietal cortices, striatum, and thalamus, with significant HIV by angle interactions emerging in the prefrontal cortex and caudate. Results indicate that HIV infection is associated with altered brain response to mental rotation in fronto-striato-parietal pathways, which may reflect compensatory strategies, recruitment of additional brain regions, and/or increased neuroenergetic demands during mental rotation needed to offset underlying HIV-associated neural injury.

  1. The contribution of the human posterior parietal cortex to episodic memory.

    PubMed

    Sestieri, Carlo; Shulman, Gordon L; Corbetta, Maurizio

    2017-02-17

    The posterior parietal cortex (PPC) is traditionally associated with attention, perceptual decision making and sensorimotor transformations, but more recent human neuroimaging studies support an additional role in episodic memory retrieval. In this Opinion article, we present a functional-anatomical model of the involvement of the PPC in memory retrieval. Parietal regions involved in perceptual attention and episodic memory are largely segregated and often show a push-pull relationship, potentially mediated by prefrontal regions. Moreover, different PPC regions carry out specific functions during retrieval - for example, representing retrieved information, recoding this information based on task demands, or accumulating evidence for memory decisions.

  2. Context-dependent interactions of left posterior inferior frontal gyrus in a local visual search task unrelated to language.

    PubMed

    Manjaly, Zina M; Marshall, John C; Stephan, Klaas E; Gurd, Jennifer M; Zilles, Karl; Fink, Gereon R

    2005-01-01

    The Embedded Figures Task (EFT) involves search for a target hidden in a complex geometric pattern. Even though the EFT is designed to probe local visual search functions, not language-related processes, neuropsychological studies have demonstrated a strong association between aphasia and impairment on this task. A potential explanation for this relationship was offered by a recent functional MRI study (Manjaly et al., 2003), which demonstrated that a part of the left posterior inferior frontal gyrus (pIFG), overlapping with Broca's region, is crucially involved in the execution of the EFT. This result suggested that pIFG, an area strongly associated with language-related functions, is also part of a network subserving cognitive functions unrelated to language. In this study, we tested this conjecture by analysing the data of Manjaly et al. for context-dependent functional interactions of the pIFG during execution of the EFT. The results showed that during EFT, compared to a similar visual matching task with minimal local search components, pIFG changed its interactions with areas commonly involved in visuospatial processing: Increased contributions to neural activity in left posterior parietal cortex, cerebellar vermis, and extrastriate areas bilaterally, as well as decreased contributions to bilateral temporo-parietal cortex, posterior cingulate cortex, and left dorsal premotor cortex were found. These findings demonstrate that left pIFG can be involved in nonlanguage processes. More generally, however, they provide a concrete example of the notion that there is no general one-to-one mapping between cognitive functions and the activations of individual areas. Instead, it is the spatiotemporal pattern of functional interactions between areas that is linked to a particular cognitive context.

  3. Traumatic neuroma of the inferior alveolar nerve: a case report.

    PubMed

    Arribas-García, Ignacio; Alcalá-Galiano, Andrea; Gutiérrez, Ramón; Montalvo-Moreno, Juan José

    2008-03-01

    Traumatic neuromas are rare entities which characteristically arise subsequently to surgery and are usually accompanied by pain, typically neuralgic. We present an unusual case of an intraosseous traumatic neuroma of the inferior alveolar nerve following tooth extraction. A 56-year-old man consulted for paresthesias and hyperesthesia in the left mandibular region following extraction of the left mandibular third molar (#38). The panoramic radiograph revealed a radiolucent lesion in the inferior alveolar nerve canal, and CT demonstrated the existence of a mass within the canal, producing widening of the same. Nerve-sparing excisional biopsy was performed. Histopathology and immunohistochemistry were consistent with traumatic neuroma of the left inferior alveolar nerve. After 3 years of follow-up, the patient is asymptomatic and there are no signs of recurrence.

  4. Variant Inferior Alveolar Nerves and Implications for Local Anesthesia

    PubMed Central

    Wolf, Kevin T.; Brokaw, Everett J.; Bell, Andrea; Joy, Anita

    2016-01-01

    A sound knowledge of anatomical variations that could be encountered during surgical procedures is helpful in avoiding surgical complications. The current article details anomalous morphology of inferior alveolar nerves encountered during routine dissection of the craniofacial region in the Gross Anatomy laboratory. We also report variations of the lingual nerves, associated with the inferior alveolar nerves. The variations were documented and a thorough review of literature was carried out. We focus on the variations themselves, and the clinical implications that these variations present. Thorough understanding of variant anatomy of the lingual and inferior alveolar nerves may determine the success of procedural anesthesia, the etiology of pathologic processes, and the avoidance of surgical misadventure. PMID:27269666

  5. The Development of Hypertrophic Inferior Olivary Nucleus in Oculopalatal Tremor.

    PubMed

    Jun, Bokkwan

    2016-12-01

    Oculopalatal tremor is an acquired clinical condition resulting from the interruption of the dentato-rubro-olivary neuronal pathway. The signal change in inferior olivary nucleus and its hypertrophy on magnetic resonance imaging (MRI) can be observed prior to the development of symptomatic oculopalatal tremor. This is a case of the fourth cranial nerve palsy followed by oculopalatal tremor, and increased signal intensity in inferior olivary nucleus on MRI was observed in 7 months after damage to the dentate-rubro-olivary pathway and 5 months prior to the development of oscillopsia and oculopalatal tremor.

  6. Rapid automatic segmentation of the human cerebellum and its lobules (RASCAL)--implementation and application of the patch-based label-fusion technique with a template library to segment the human cerebellum.

    PubMed

    Weier, Katrin; Fonov, Vladimir; Lavoie, Karyne; Doyon, Julien; Collins, D Louis

    2014-10-01

    Reliable and fast segmentation of the human cerebellum with its complex architecture of lobes and lobules has been a challenge for the past decades. Emerging knowledge of the functional integration of the cerebellum in various sensori-motor and cognitive-behavioral circuits demands new automatic segmentation techniques, with accuracies similar to manual segmentations, but applicable to large subject numbers in a reasonable time frame. This article presents the development and application of a novel pipeline for rapid automatic segmentation of the human cerebellum and its lobules (RASCAL) combining patch-based label-fusion and a template library of manually labeled cerebella of 16 healthy controls from the International Consortium for Brain Mapping (ICBM) database. Leave-one-out experiments revealed a good agreement between manual and automatic segmentations (Dice kappa = 0.82). Intraclass correlation coefficients (ICC) were calculated to test reliability of segmented volumes and were highest (ICC > 0.9) for global measures (total and hemispherical grey and white matter) followed by larger lobules of the posterior lobe (ICC > 0.8). Further we applied the pipeline to all 152 young healthy controls of the ICBM database to look for hemispheric and gender differences. The results demonstrated larger native space volumes in men then women (mean (± SD) total cerebellar volume in women = 217 cm(3) (± 26), men = 259 cm(3) (± 29); P < 0.001). Significant gender-by-hemisphere interaction was only found in stereotaxic space volumes for white matter core (men > women) and anterior lobe volume (women > men). This new method shows great potential for the precise and efficient analysis of the cerebellum in large patient cohorts.

  7. Calcium Uptake and Release through Sarcoplasmic Reticulum in the Inferior Oblique Muscles of Patients with Inferior Oblique Overaction

    PubMed Central

    Kim, Hee Seon; Chang, Yoon-Hee; Kim, Do Han; Park, So Ra; Han, Sueng-Han

    2006-01-01

    We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p<0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA. PMID:16642550

  8. Coherence and Consciousness: Study of Fronto-Parietal Gamma Synchrony in Patients with Disorders of Consciousness.

    PubMed

    Cavinato, Marianna; Genna, Clara; Manganotti, Paolo; Formaggio, Emanuela; Storti, Silvia Francesca; Campostrini, Stefania; Arcaro, Chiara; Casanova, Emanuela; Petrone, Valeria; Piperno, Roberto; Piccione, Francesco

    2015-07-01

    Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N = 26) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient.

  9. Altered network properties of the fronto-parietal network and the thalamus in impaired consciousness.

    PubMed

    Crone, Julia Sophia; Soddu, Andrea; Höller, Yvonne; Vanhaudenhuyse, Audrey; Schurz, Matthias; Bergmann, Jürgen; Schmid, Elisabeth; Trinka, Eugen; Laureys, Steven; Kronbichler, Martin

    2014-01-01

    Recovery of consciousness has been associated with connectivity in the frontal cortex and parietal regions modulated by the thalamus. To examine this model and to relate alterations to deficits in cognitive functioning and conscious processing, we investigated topological network properties in patients with chronic disorders of consciousness recovered from coma. Resting state fMRI data of 34 patients with unresponsive wakefulness syndrome and 25 in minimally conscious state were compared to 28 healthy controls. We investigated global and local network characteristics. Additionally, behavioral measures were correlated with the local metrics of 28 regions within the fronto-parietal network and the thalamus. In chronic disorders of consciousness, modularity at the global level was reduced suggesting a disturbance in the optimal balance between segregation and integration. Moreover, network properties were altered in several regions which are associated with conscious processing (particularly, in medial parietal, and frontal regions, as well as in the thalamus). Between minimally conscious and unconscious patients the local efficiency of medial parietal regions differed. Alterations in the thalamus were particularly evident in non-conscious patients. Most of the regions affected in patients with impaired consciousness belong to the so-called 'rich club' of highly interconnected central nodes. Disturbances in their topological characteristics have severe impact on information integration and are reflected in deficits in cognitive functioning probably leading to a total breakdown of consciousness.

  10. Lateralization of Egocentric and Allocentric Spatial Processing after Parietal Brain Lesions

    ERIC Educational Resources Information Center

    Iachini, Tina; Ruggiero, Gennaro; Conson, Massimiliano; Trojano, Luigi

    2009-01-01

    The purpose of this paper was to verify whether left and right parietal brain lesions may selectively impair egocentric and allocentric processing of spatial information in near/far spaces. Two Right-Brain-Damaged (RBD), 2 Left-Brain-Damaged (LBD) patients (not affected by neglect or language disturbances) and eight normal controls were submitted…

  11. Static magnetic field stimulation over parietal cortex enhances somatosensory detection in humans.

    PubMed

    Carrasco-López, Carmen; Soto-León, Vanesa; Céspedes, Virginia; Profice, Paolo; Strange, Bryan A; Foffani, Guglielmo; Oliviero, Antonio

    2017-03-09

    The role of neuronal oscillations in human somatosensory perception is currently unclear. To address this, here we employ non-invasive brain stimulation to artificially modulate cortical network dynamics in the context of neurophysiological and behavioral recordings. We demonstrate that transcranial static magnetic stimulation (tSMS) over the somatosensory parietal cortex increases oscillatory power specifically in the alpha range, without significantly affecting bottom-up thalamo-cortical inputs indexed by the early cortical component of somatosensory evoked potentials. Critically, we next show that parietal tSMS enhances the detection of near-threshold somatosensory stimuli. Interestingly, this behavioral improvement reflects a decrease of habituation to somatosensation. Our data therefore provide causal evidence that somatosensory perception depends on parietal alpha activity. Artificially increasing alpha power by placing a powerful magnetic field over the parietal cortex overcomes the natural decline in detection probability of a repeated near-threshold sensory stimulus.SignificanceStatement Artificially increasing alpha power by placing a powerful magnetic field over the somatosensory cortex overcomes the natural decline in detection probability of a repeated near-threshold sensory stimulus.

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

    ERIC Educational Resources Information Center

    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…

  13. A new view of hemineglect based on the response properties of parietal neurones.

    PubMed Central

    Pouget, A; Sejnowski, T J

    1997-01-01

    Lesion studies of the parietal cortex have led to a wide range of conclusions regarding the coordinate reference frame in which hemineglect is expressed. A model of spatial representation in the parietal cortex has recently been developed in which the position of an object is not encoded in a particular frame of reference, but instead involves neurones computing basis functions of sensory inputs. In this type of representation, a nonlinear sensorimotor transformation of an object is represented in a population of units having the response properties of neurones that are observed in the parietal cortex. A simulated lesion in a basis-function representation was found to replicate three of the most important aspects of hemineglect: (i) the model behaved like parietal patients in line-cancellation and line-bisection experiments; (ii) the deficit affected multiple frames of reference; and (iii) the deficit could be object-centred. These results support the basis-function hypothesis for spatial representations and provide a testable computational theory of hemineglect at the level of single cells. PMID:9368933

  14. Contralateral somatosensory neglect in unrestrained rats after lesion of the parietal cortex of the left hemisphere.

    PubMed

    Holm, S; Mogensen, J

    1993-01-01

    Three groups of rats were studied: a sham operated control group and two groups in which the parietal "association" cortex had been ablated in the left and right hemispheres respectively. Twenty-four hours and 8 days postoperatively the animals were subjected to a test in which their responsiveness to lateralized somatosensory stimuli was measured while the rats were left unrestrained. Additionally, an activity cage locomotion test followed immediately upon both tests of somatosensory responsiveness. Twenty-four hours postoperatively the animals in which the parietal cortex of the left hemisphere had been ablated demonstrated a significant contralateral neglect of somatosensory stimuli while the group in which the right parietal cortex had been ablated only exhibited a non-significant tendency to a contralateral neglect. While the activity cage test did not reveal an overall difference in the activity level of the three groups the latency to initiate locomotion in the activity cage was found to be significantly decreased in both ablated groups. Eight days postoperatively both ablated groups appeared fully recovered. It is concluded that ablations of the parietal "association" cortex of the rat are associated with a syndrome of contralateral somatosensory neglect that can even be demonstrated if the animals are left unrestrained during testing.

  15. The Role of the Right Posterior Parietal Cortex in Temporal Order Judgment

    ERIC Educational Resources Information Center

    Woo, Sung-Ho; Kim, Ki-Hyun; Lee, Kyoung-Min

    2009-01-01

    Perceived order of two consecutive stimuli may not correspond to the order of their physical onsets. Such a disagreement presumably results from a difference in the speed of stimulus processing toward central decision mechanisms. Since previous evidence suggests that the right posterior parietal cortex (PPC) plays a role in modulating the…

  16. The precision of value-based choices depends causally on fronto-parietal phase coupling

    PubMed Central

    Polanía, Rafael; Moisa, Marius; Opitz, Alexander; Grueschow, Marcus; Ruff, Christian C.

    2015-01-01

    Which meal would you like today, chicken or pasta? For such value-based choices, organisms must flexibly integrate various types of sensory information about internal states and the environment to transform them into actions. Recent accounts suggest that these choice-relevant processes are mediated by information transfer between functionally specialized but spatially distributed brain regions in parietal and prefrontal cortex; however, it remains unclear whether such fronto-parietal communication is causally involved in guiding value-based choices. We find that transcranially inducing oscillatory desynchronization between the frontopolar and -parietal cortex leads to more inaccurate choices between food rewards while leaving closely matched perceptual decisions unaffected. Computational modelling shows that this exogenous manipulation leads to imprecise value assignments to the choice alternatives. Thus, our study demonstrates that accurate value-based decisions critically involve coherent rhythmic information transfer between fronto-parietal brain areas and establishes an experimental approach to non-invasively manipulate the precision of value-based choices in humans. PMID:26290482

  17. Attentional Demands Predict Short-Term Memory Load Response in Posterior Parietal Cortex

    ERIC Educational Resources Information Center

    Magen, Hagit; Emmanouil, Tatiana-Aloi; McMains, Stephanie A.; Kastner, Sabine; Treisman, Anne

    2009-01-01

    Limits to the capacity of visual short-term memory (VSTM) indicate a maximum storage of only 3 or 4 items. Recently, it has been suggested that activity in a specific part of the brain, the posterior parietal cortex (PPC), is correlated with behavioral estimates of VSTM capacity and might reflect a capacity-limited store. In three experiments that…

  18. Carbamoylcholine and gastrin induce inositol lipid turnover in canine gastric parietal cells

    SciTech Connect

    Chiba, T.; Fisher, S.K.; Park, J.; Seguin, E.B.; Agranoff, B.W.; Yamada, Tadataka )

    1988-07-01

    The potential role of inositol phospholipid turnover in mediating acid secretion was examined in a preparation enriched for isolated canine gastric parietal cells. The stimulatory effects of carbamoylcholine (carbachol) and gastrin on parietal cell uptake of ({sup 14}C)aminopyrine were linked to dose- and time-dependent selective reduction in cellular phosphatidylinositol content, although the specific fatty acid composition of the phosphoinositides was not altered. Analysis of ({sup 3}H)inositol phosphates accumulated in cells prelabeled with ({sup 3}H)inositol revealed an increase in labeled inositol trisphosphate by 5 min of incubation with either carbachol or gastrin. Furthermore, after preincubation of parietal cells in medium containing ({sup 32}P)orthophosphate, the two secretagogues elicited a time-dependent decrease in {sup 32}P labeling of phosphatidylinositol 4,5-bisphosphate and concomitant increase in labeling of phosphatidic acid. These data demonstrate that the acid secretagogue actions of carbachol and gastrin are correlated with turnover of cellular inositol phospholipids in a preparation consisting predominantly of parietal cells.

  19. Sex Differences in Parietal Lobe Morphology: Relationship to Mental Rotation Performance

    ERIC Educational Resources Information Center

    Koscik, Tim; O'Leary, Dan; Moser, David J.; Andreasen, Nancy C.; Nopoulos, Peg

    2009-01-01

    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…

  20. Reduced pepsin A processing of sonic hedgehog in parietal cells precedes gastric atrophy and transformation.

    PubMed

    Zavros, Yana; Waghray, Meghna; Tessier, Arthur; Bai, Longchuan; Todisco, Andrea; L Gumucio, Deborah; Samuelson, Linda C; Dlugosz, Andrzej; Merchant, Juanita L

    2007-11-16

    Sonic hedgehog (Shh) is not only essential to the development of the gastrointestinal tract, but is also necessary to maintain the characteristic acid-secreting phenotype of the adult stomach. Gastrin is the only hormone capable of stimulating gastric acid and is thus required to maintain functional parietal cells. We have shown previously that gastrin-null mice display gastric atrophy and metaplasia prior to progression to distal, intestinal-type gastric cancer. Because reduced levels of Shh peptide correlate with gastric atrophy, we examined whether gastrin regulates Shh expression in parietal cells. We show here that gastrin stimulates Shh gene expression and acid-dependent processing of the 45-kDa Shh precursor to the 19-kDa secreted peptide in primary parietal cell cultures. This cleavage was blocked by the proton pump inhibitor omeprazole and mediated by the acid-activated protease pepsin A. Pepsin A was also the protease responsible for processing Shh in tissue extracts from human stomach. By contrast, extracts prepared from neoplastic gastric mucosa had reduced levels of pepsin A and did not process Shh. Therefore processing of Shh in the normal stomach is hormonally regulated, acid-dependent, and mediated by the aspartic protease pepsin A. Moreover parietal cell atrophy, a known pre-neoplastic lesion, correlates with loss of Shh processing.

  1. Transfer of cognitive training across magnitude dimensions achieved with concurrent brain stimulation of the parietal lobe.

    PubMed

    Cappelletti, Marinella; Gessaroli, Erica; Hithersay, Rosalyn; Mitolo, Micaela; Didino, Daniele; Kanai, Ryota; Cohen Kadosh, Roi; Walsh, Vincent

    2013-09-11

    Improvement in performance following cognitive training is known to be further enhanced when coupled with brain stimulation. Here we ask whether training-induced changes can be maintained long term and, crucially, whether they can extend to other related but untrained skills. We trained overall 40 human participants on a simple and well established paradigm assessing the ability to discriminate numerosity--or the number of items in a set--which is thought to rely on an "approximate number sense" (ANS) associated with parietal lobes. We coupled training with parietal stimulation in the form of transcranial random noise stimulation (tRNS), a noninvasive technique that modulates neural activity. This yielded significantly better and longer lasting improvement (up to 16 weeks post-training) of the precision of the ANS compared with cognitive training in absence of stimulation, stimulation in absence of cognitive training, and cognitive training coupled to stimulation to a control site (motor areas). Critically, only ANS improvement induced by parietal tRNS + Training transferred to proficiency in other parietal lobe-based quantity judgment, i.e., time and space discrimination, but not to quantity-unrelated tasks measuring attention, executive functions, and visual pattern recognition. These results indicate that coupling intensive cognitive training with tRNS to critical brain regions resulted not only in the greatest and longer lasting improvement of numerosity discrimination, but importantly in this enhancement being transferable when trained and untrained abilities are carefully chosen to share common cognitive and neuronal components.

  2. Prehension Movements in a Patient (AC) with Posterior Parietal Cortex Damage and Posterior Callosal Section

    ERIC Educational Resources Information Center

    Frak, Victor; Paulignan, Yves; Jeannerod, Marc; Michel, Francois; Cohen, Henri

    2006-01-01

    Prehension movements of the right hand were recorded in a right-handed man (AC), with an injury to the left posterior parietal cortex (PPC) and with a section of the left half of the splenium. The kinematic analysis of AC's grasping movements in direct and perturbed conditions was compared to that of five control subjects. A novel effect in…

  3. Temporo-Parietal Junction Activity in Theory-of-Mind Tasks: Falseness, Beliefs, or Attention

    ERIC Educational Resources Information Center

    Aichhorn, Markus; Perner, Josef; Weiss, Benjamin; Kronbichler, Martin; Staffen, Wolfgang; Ladurner, Gunther

    2009-01-01

    By combining the false belief (FB) and photo (PH) vignettes to identify theory-of-mind areas with the false sign (FS) vignettes, we re-establish the functional asymmetry between the left and right temporo-parietal junction (TPJ). The right TPJ (TPJ-R) is specially sensitive to processing belief information, whereas the left TPJ (TPJ-L) is equally…

  4. The Role of the Parietal Lobe in Visual Extinction Studied with Transcranial Magnetic Stimulation

    ERIC Educational Resources Information Center

    Battelli, Lorella; Alvarez, George A.; Carlson, Thomas; Pascual-Leone, Alvaro

    2009-01-01

    Interhemispheric competition between homologous areas in the human brain is believed to be involved in a wide variety of human behaviors from motor activity to visual perception and particularly attention. For example, patients with lesions in the posterior parietal cortex are unable to selectively track objects in the contralesional side of…

  5. Planning Movements in Visual and Physical Space in Monkey Posterior Parietal Cortex.

    PubMed

    Kuang, Shenbing; Morel, Pierre; Gail, Alexander

    2016-02-01

    Neurons in the posterior parietal cortex respond selectively for spatial parameters of planned goal-directed movements. Yet, it is still unclear which aspects of the movement the neurons encode: the spatial parameters of the upcoming physical movement (physical goal), or the upcoming visual limb movement (visual goal). To test this, we recorded neuronal activity from the parietal reach region while monkeys planned reaches under either normal or prism-reversed viewing conditions. We found predominant encoding of physical goals while fewer neurons were selective for visual goals during planning. In contrast, local field potentials recorded in the same brain region exhibited predominant visual goal encoding, similar to previous imaging data from humans. The visual goal encoding in individual neurons was neither related to immediate visual input nor to visual memory, but to the future visual movement. Our finding suggests that action planning in parietal cortex is not exclusively a precursor of impending physical movements, as reflected by the predominant physical goal encoding, but also contains spatial kinematic parameters of upcoming visual movement, as reflected by co-existing visual goal encoding in neuronal spiking. The co-existence of visual and physical goals adds a complementary perspective to the current understanding of parietal spatial computations in primates.

  6. Magnetization transfer imaging of suicidal patients with major depressive disorder.

    PubMed

    Chen, Ziqi; Zhang, Huawei; Jia, Zhiyun; Zhong, Jingjie; Huang, Xiaoqi; Du, Mingying; Chen, Lizhou; Kuang, Weihong; Sweeney, John A; Gong, Qiyong

    2015-04-08

    Magnetization transfer imaging (MTI) provides a quantitative measure of the macromolecular structural integrity of brain tissue, as represented by magnetization transfer ratio (MTR). In this study, we utilized MTI to identify biophysical alterations in MDD patients with a history of suicide attempts relative to MDD patients without such history. The participants were 36 medication-free MDD patients, with (N = 17) and without (N = 19) a history of a suicide attempt, and 28 healthy controls matched for age and gender. Whole brain voxel-based analysis was used to compare MTR across three groups and to analyze correlations with symptom severity and illness duration. We identified decreased MTR in left inferior parietal lobule and right superior parietal lobule in suicide attempters relative to both non-attempters and controls. Non-attempters also showed significantly reduced MTR in left inferior parietal lobule relative to controls, as well as an MTR reduction in left cerebellum. These abnormalities were not correlated with symptom severity or illness duration. Depressed patients with a history of suicide attempt showed bilateral abnormalities in parietal cortex compared to nonsuicidal depressed patients and healthy controls. Parietal lobe abnormalities might cause attentional dysfunction and impaired decision making to increase risk for suicidal behavior in MDD.

  7. Inferior Colliculus Lesions Impair Eyeblink Conditioning in Rats

    ERIC Educational Resources Information Center

    Freeman, John H.; Halverson, Hunter E.; Hubbard, Erin M.

    2007-01-01

    The neural plasticity necessary for acquisition and retention of eyeblink conditioning has been localized to the cerebellum. However, the sources of sensory input to the cerebellum that are necessary for establishing learning-related plasticity have not been identified completely. The inferior colliculus may be a source of sensory input to the…

  8. Inferior vena cava leiomyosarcoma: vascular reconstruction is not always mandatory

    PubMed Central

    Slimane, Maher; Yahia, Nada Belhaj; Bouaziz, Hanene; Bouzaine, Hatem; Benhassouna, Jamel; Dhieb, Tarek Ben; Hechiche, Monia; Gammoudi, Amor; Rahal, Khaled

    2016-01-01

    Leiomyosarcoma (LMS) of inferior vena cava is a rare and aggressive tumor, arising from the smooth muscle cells in the vessel wall. A large complete surgical resection is the essential treatment. The need of vascular reconstruction is not always mandatory. It’s above all to understand the place of the reconstruction with artificial vascular patch prosthetics of vena cave after a large resection of the tumor. We rapport two cases of LMS of inferior vena cava in two women who underwent successful large resection of tumor and lower segment of inferior vena cava. In first case, reconstruction of the inferior vena cava was not performed because of the development of venous collaterals derivation. In the second case reconstruction was done using Dacron interposition graft. The necessity of a large resection in management of primary leiomyosarcoma of vena cave makes sometimes unavoidable the sacrifice of a portion of the vena. Indeed, a better comprehension of the development of venous derivation may render unnecessary the reconstruction. PMID:28154642

  9. Traumatic longitudinal splitting of the inferior rectus muscle

    PubMed Central

    Laursen, Jessica; Demer, Joseph L.

    2011-01-01

    Orbital floor fractures and associated injuries can cause strabismus. We present the case of a 34-year-old man with incomitant strabismus following orbital reconstruction after a high-impact baseball injury. Multipositional, high-resolution magnetic resonance imaging (MRI) revealed extensive longitudinal splitting of the inferior rectus muscle by an orbital floor implant that separated its orbital and global layers. PMID:21463958

  10. Inferior pancreaticoduodenal artery aneurysm associated with common hepatic artery occlusion.

    PubMed

    Bracale, G; Porcellini, M; Bernardo, B; Selvetella, L; Renda, A

    1996-12-01

    A unique case of true inferior pancreaticoduodenal artery aneurysm (IPDA) associated with occlusion of common hepatic artery is reported. Radiological and MRI findings are described. Because of high risk of visceral ischemia that contraindicated a percutaneous transluminal embolization, a successful tangential resection of aneurysm was performed.

  11. Endodontic-related inferior alveolar nerve and mental foramen paresthesia.

    PubMed

    Morse, D R

    1997-10-01

    Paresthesia is a condition that involves perverted sensations of pain, touch, or temperature. It has a variety of possible causes. This article presents a literature review and case reports of endodontically related inferior alveolar nerve and mental foramen paresthesia. Nondrug prevention methods and the dental uses of dexamethasone are also discussed.

  12. Hemispheric Differences within the Fronto-Parietal Network Dynamics Underlying Spatial Imagery

    PubMed Central

    Sack, Alexander T.; Schuhmann, Teresa

    2012-01-01

    Spatial imagery refers to the inspection and evaluation of spatial features (e.g., distance, relative position, configuration) and/or the spatial manipulation (e.g., rotation, shifting, reorienting) of mentally generated visual images. In the past few decades, psychophysical as well as functional brain imaging studies have indicated that any such processing of spatially coded information and/or manipulation based on mental images (i) is subject to similar behavioral demands and limitations as in the case of spatial processing based on real visual images, and (ii) consistently activates several nodes of widely distributed cortical networks in the brain. These nodes include areas within both, the dorsal fronto-parietal as well as ventral occipito-temporal visual processing pathway, representing the “what” versus “where” aspects of spatial imagery. We here describe evidence from functional brain imaging and brain interference studies indicating systematic hemispheric differences within the dorsal fronto-parietal networks during the execution of spatial imagery. Importantly, such hemispheric differences and functional lateralization principles are also found in the effective brain network connectivity within and across these networks, with a direction of information flow from anterior frontal/premotor regions to posterior parietal cortices. In an attempt to integrate these findings of hemispheric lateralization and fronto-to-parietal interactions, we argue that spatial imagery constitutes a multifaceted cognitive construct that can be segregated in several distinct mental sub processes, each associated with activity within specific lateralized fronto-parietal (sub) networks, forming the basis of the here proposed dynamic network model of spatial imagery. PMID:22754546

  13. Immune response to Mycobacterium tuberculosis infection in the parietal pleura of patients with tuberculous pleurisy.

    PubMed

    Caramori, Gaetano; Lasagna, Lisa; Casalini, Angelo G; Adcock, Ian M; Casolari, Paolo; Contoli, Marco; Tafuro, Federica; Padovani, Anna; Chung, Kian Fan; Barnes, Peter J; Papi, Alberto; Rindi, Guido; Bertorelli, Giuseppina

    2011-01-01

    The T lymphocyte-mediated immune response to Mycobacterium tuberculosis infection in the parietal pleura of patients with tuberculous pleurisy is unknown. The aim of this study was to investigate the immune response in the parietal pleura of tuberculous pleurisy compared with nonspecific pleuritis. We have measured the numbers of inflammatory cells particularly T-cell subsets (Th1/Th2/Th17/Treg cells) in biopsies of parietal pleura obtained from 14 subjects with proven tuberculous pleurisy compared with a control group of 12 subjects with nonspecific pleuritis. The number of CD3+, CD4+ and CCR4+ cells and the expression of RORC2 mRNA were significantly increased in the tuberculous pleurisy patients compared with the nonspecific pleuritis subjects. The number of toluidine blue+ cells, tryptase+ cells and GATA-3+ cells was significantly decreased in the parietal pleura of patients with tuberculous pleurisy compared with the control group of nonspecific pleuritis subjects. Logistic regression with receiver operator characteristic (ROC) analysis for the three single markers was performed and showed a better performance for GATA-3 with a sensitivity of 75%, a specificity of 100% and an AUC of 0.88. There was no significant difference between the two groups of subjects in the number of CD8, CD68, neutrophil elastase, interferon (IFN)-γ, STAT4, T-bet, CCR5, CXCR3, CRTH2, STAT6 and FOXP3 positive cells. Elevated CD3, CD4, CCR4 and Th17 cells and decreased mast cells and GATA-3+ cells in the parietal pleura distinguish patients with untreated tuberculous pleurisy from those with nonspecific pleuritis.

  14. Fronto-Parietal Connectivity Is a Non-Static Phenomenon with Characteristic Changes during Unconsciousness

    PubMed Central

    Kochs, Eberhard F.; Ilg, Rüdiger; Schneider, Gerhard

    2014-01-01

    Background It has been previously shown that loss of consciousness is associated with a breakdown of dominating fronto-parietal feedback connectivity as assessed by electroencephalogram (EEG) recordings. Structure and strength of network connectivity may change over time. Aim of the current study is to investigate cortico-cortical connectivity at different time intervals during consciousness and unconsciousness. For this purpose, EEG symbolic transfer entropy (STEn) was calculated to indicate cortico-cortical information transfer at different transfer times. Methods The study was performed in 15 male volunteers. 29-channel EEG was recorded during consciousness and propofol-induced unconsciousness. EEG data were analyzed by STEn, which quantifies intensity and directionality of the mutual information flow between two EEG channels. STEn was computed over fronto-parietal channel pair combinations (10 s length, 0.5–45 Hz total bandwidth) to analyze changes of intercortical directional connectivity. Feedback (fronto → parietal) and feedforward (parieto → frontal) connectivity was calculated for transfer times from 25 ms to 250 ms in 5 ms steps. Transfer times leading to maximum directed interaction were identified to detect changes of cortical information transfer (directional connectivity) induced by unconsciousness (p<0.05). Results The current analyses show that fronto-parietal connectivity is a non-static phenomenon. Maximum detected interaction occurs at decreased transfer times during propofol-induced unconsciousness (feedback interaction: 60 ms to 40 ms, p = 0.002; feedforward interaction: 65 ms to 45 ms, p = 0.001). Strength of maximum feedback interaction decreases during unconsciousness (p = 0.026), while no effect of propofol was observed on feedforward interaction. During both consciousness and unconsciousness, intensity of fronto-parietal interaction fluctuates with increasing transfer times. Conclusion Non-stationarity of directional

  15. Critical brain regions for action recognition: lesion symptom mapping in left hemisphere stroke.

    PubMed

    Kalénine, Solène; Buxbaum, Laurel J; Coslett, Harry Branch

    2010-11-01

    A number of conflicting claims have been advanced regarding the role of the left inferior frontal gyrus, inferior parietal lobe and posterior middle temporal gyrus in action recognition, driven in part by an ongoing debate about the capacities of putative mirror systems that match observed and planned actions. We report data from 43 left hemisphere stroke patients in two action recognition tasks in which they heard and saw an action word ('hammering') and selected from two videoclips the one corresponding to the word. In the spatial recognition task, foils contained errors of body posture or movement amplitude/timing. In the semantic recognition task, foils were semantically related (sawing). Participants also performed a comprehension control task requiring matching of the same verbs to objects (hammer). Using regression analyses controlling for both the comprehension control task and lesion volume, we demonstrated that performance in the semantic gesture recognition task was predicted by per cent damage to the posterior temporal lobe, whereas the spatial gesture recognition task was predicted by per cent damage to the inferior parietal lobule. A whole-brain voxel-based lesion symptom-mapping analysis suggested that the semantic and spatial gesture recognition tasks were associated with lesioned voxels in the posterior middle temporal gyrus and inferior parietal lobule, respectively. The posterior middle temporal gyrus appears to serve as a central node in the association of actions and meanings. The inferior parietal lobule, held to be a homologue of the monkey parietal mirror neuron system, is critical for encoding object-related postures and movements, a relatively circumscribed aspect of gesture recognition. The inferior frontal gyrus, on the other hand, was not predictive of performance in any task, suggesting that previous claims regarding its role in action recognition may require refinement.

  16. Lack of taxonomic information from parietal spine size invalidates subspecies in the Atlantic hookear sculpin Artediellus atlanticus.

    PubMed

    Rees, D; Byrkjedal, I

    2013-01-01

    An analysis of 107 individuals of Atlantic hookear sculpin Artediellus atlanticus from the Barents Sea-Svalbard region and from north-east Greenland shows that the state of the parietal spines, although not randomly distributed geographically, occurs sympatrically. They do not diagnostically describe populations. They are therefore inept for subspecies delimitation into Artediellus atlanticus atlanticus, Artediellus atlanticus corniger and Artediellus atlanticus europaeus. Sympatric occurrence of parietal spine states called for a molecular approach to look for differences at a species level. Sequencing the mitochondrial genes, cytochrome oxidase c subunit I (coI) and cytochrome b (cytb), shows no difference between individuals with different parietal spine size. Thus, there is no evidence of the spine states representing species-level variation. The study shows that parietal spine size has no taxonomic information for this species. The patterns of variation in parietal spine size differ to some degree between the sexes.

  17. Matrix metalloproteinase-9 expression is enhanced in renal parietal epithelial cells of zucker diabetic Fatty rats and is induced by albumin in in vitro primary parietal cell culture.

    PubMed

    Zhang, Yuanyuan; George, Jasmine; Li, Yun; Olufade, Rebecca; Zhao, Xueying

    2015-01-01

    As a subfamily of matrix metalloproteinases (MMPs), gelatinases including MMP-2 and MMP-9 play an important role in remodeling and homeostasis of the extracellular matrix. However, conflicting results have been reported regarding their expression level and activity in the diabetic kidney. This study investigated whether and how MMP-9 expression and activity were changed in glomerular epithelial cells upon albumin overload. In situ zymography, immunostaining and Western blot for renal MMP gelatinolytic activity and MMP-9 protein expression were performed in Zucker lean and Zucker diabetic rats. Confocal microscopy revealed a focal increase in gelatinase activity and MMP-9 protein in the glomeruli of diabetic rats. Increased glomerular MMP-9 staining was mainly observed in hyperplastic parietal epithelial cells (PECs) expressing claudin-1 in the diabetic kidneys. Interestingly, increased parietal MMP-9 was often accompanied by decreased staining for podocyte markers (nephrin and podocalyxin) in the sclerotic area of affected glomeruli in diabetic rats. Additionally, urinary excretion of podocyte marker proteins was significantly increased in association with the levels of MMP-9 and albumin in the urine of diabetic animals. To evaluate the direct effect of albumin on expression and activity of MMP-9, primary cultured rat glomerular PECs were incubated with rat serum albumin (0.25 - 1 mg/ml) for 24 - 48 hrs. MMP-9 mRNA levels were significantly increased following albumin treatment. Meanwhile, albumin administration resulted in a dose-dependent increase in MMP-9 protein and activity in culture supernatants of PECs. Moreover, albumin activated p44/42 mitogen-activated protein kinase (MAPK) in PECs. Inhibition of p44/42 MAPK suppressed albumin-induced MMP-9 secretion from glomerular PECs. Taken together, we have demonstrated that an up-regulation of MMP-9 in activated parietal epithelium is associated with a loss of adjacent podocytes in progressive diabetic nephropathy

  18. White and Gray Matter Volume Changes and Correlation with Visual Evoked Potential in Patients with Optic Neuritis: A Voxel-Based Morphometry Study

    PubMed Central

    Huang, Xin; Zhang, Qiang; Hu, Pei-Hong; Zhong, Yu-Lin; Zhang, Ying; Wei, Rong; Xu, Ting-Ting; Shao, Yi

    2016-01-01

    Background The aim of this study was to investigate potential morphological alterations of gray and white matter in patients with optic neuritis (ON) and their relationship with behavioral performance, using voxel-based morphometry (VBM). Material/Methods Twelve (4 males, 8 females) patients with ON and 12 (4 males, 8 females) age-, sex-, and education-matched healthy controls (HCs) underwent magnetic resonance imaging (MRI). Imaging data were analyzed using two-sample t tests to identify group differences in gray and white matter volume (GMV, WMV). Correlation analysis was used to explore relationships between observed GMV and WMV of different areas and visual evoked potential (VEP) in ON. Results Compared with HCs, ON patients had: significantly decreased GMV in the left postcentral gyrus, left inferior frontal gyrus, left anterior cingulate, left and right middle frontal gyrus, and right inferior parietal lobule; decreased WMV in the left middle frontal gyrus, right superior frontal gyrus, left precentral gyrus and right inferior parietal lobule; and increased WMV in the left fusiform gyrus and left inferior parietal lobule. VEP latency of the right eye in ON correlated positively with WMV signal value of the left fusiform gyrus (r=0.726, p=0.008), and negatively with GMV signal value of the right inferior parietal lobule (r=−0.611, p=0.035). Duration of ON correlated negatively with WMV signal value of the right superior frontal gyrus (r=−0.662, p=0.019), while best-corrected visual acuity (VA) of the right eye correlated negatively with WMV signal value of the left middle frontal gyrus (r=−0.704, p=0.011). Conclusions These results suggest significant brain involvement in ON, which may reflect the underlying pathologic mechanism. Correlational results demonstrate that VEP in ON is closely associated with WMV and GMV atrophy in many brain regions. PMID:27045330

  19. Resilience to the contralateral visual field bias as a window into object representations.

    PubMed

    Garcea, Frank E; Kristensen, Stephanie; Almeida, Jorge; Mahon, Bradford Z

    2016-08-01

    Viewing images of manipulable objects elicits differential blood oxygen level-dependent (BOLD) contrast across parietal and dorsal occipital areas of the human brain that support object-directed reaching, grasping, and complex object manipulation. However, it is unknown which object-selective regions of parietal cortex receive their principal inputs from the ventral object-processing pathway and which receive their inputs from the dorsal object-processing pathway. Parietal areas that receive their inputs from the ventral visual pathway, rather than from the dorsal stream, will have inputs that are already filtered through object categorization and identification processes. This predicts that parietal regions that receive inputs from the ventral visual pathway should exhibit object-selective responses that are resilient to contralateral visual field biases. To test this hypothesis, adult participants viewed images of tools and animals that were presented to the left or right visual fields during functional magnetic resonance imaging (fMRI). We found that the left inferior parietal lobule showed robust tool preferences independently of the visual field in which tool stimuli were presented. In contrast, a region in posterior parietal/dorsal occipital cortex in the right hemisphere exhibited an interaction between visual field and category: tool-preferences were strongest contralateral to the stimulus. These findings suggest that action knowledge accessed in the left inferior parietal lobule operates over inputs that are abstracted from the visual input and is contingent on analysis by the ventral visual pathway, consistent with its putative role in supporting object manipulation knowledge.

  20. Care of patients with deep inferior epigastric perforator reconstruction.

    PubMed

    Long, Laura; Israelian, Amy

    2013-01-01

    Recent trends reflect greater numbers of women opting for mastectomy for invasive breast cancer. Breast reconstruction, either at the time of mastectomy or later, is increasingly an option patients prefer. Although many women opt for implants, reconstruction using autologous tissue offers several advantages including tissue that feels more natural and will age naturally with the patient. The deep inferior epigastric perforator flap has emerged as an alternative to the transverse rectus abdominis myocutaneous flap and allows for preservation of the underlying abdominal muscle. As greater numbers of surgeons are able to offer this microvascular alternative, nurses will care for these postoperative patients in the intensive care unit and medical/surgical settings. This article reviews the evaluation of patients for deep inferior epigastric perforator reconstruction and the unique complexities of postoperative nursing care for these patients.

  1. Enhanced Modiolar Stimulation Effects in the Inferior Colliculus

    DTIC Science & Technology

    2007-11-02

    stimulation. Keywords: Cochlear Implant , Inferior Colliculus, Modiolar Stimulation I. INTRODUCTION Cochlear implants are used to provide hearing sensation...to the sensoneurally deaf. Bipolar electrical stimulation of a scala tympani cochlear implant produces a localized stimulus which has been measured...to diminish at about 9dB/octave [1]. Blamey et al. (1994) describes both a perceived low frequency shift by cochlear implant patients in response to

  2. Management of the Thrombosed Filter-Bearing Inferior Vena Cava

    PubMed Central

    Sildiroglu, Onur; Ozer, Harun; Turba, Ulku Cenk

    2012-01-01

    Inferior vena cava (IVC) filter thrombosis is a complex problem. Thrombus within an IVC filter may range from an asymptomatic small thrombus to critical IVC occlusion that affects both lower extremities. The published experience of IVC thrombosis management in relation to filters is either anecdotal or limited to a small group of patients; however, endovascular treatment methods appear to be safe and effective in patients with IVC thrombosis. This review focuses on filter-related IVC thrombosis and its endovascular management. PMID:23449290

  3. Leiomyosarcoma of the inferior vena cava: a case report.

    PubMed

    Nascif, Rafael Lemos; Antón, Ana Graziela Santana; Fernandes, Gabriel Lacerda; Dantas, George Caldas; Gomes, Vinícius de Araújo; Natal, Marcelo Ricardo Canuto

    2014-01-01

    The authors report a case of a 48 year-old female patient with moderate abdominal pain and bulging in the abdomen. Physical examination demonstrated the presence of a palpable abdominal mass. Computed tomography showed a heterogeneously enhancing retroperitoneal mass in close contact with the inferior vena cava. En bloc resection of the mass and of the attached vena cava segment was performed. Histological analysis revealed leiomyosarcoma.

  4. [Aneurysm of the anterior inferior cerebellar artery: case report].

    PubMed

    Adorno, Juan Oscar Alarcón; de Andrade, Guilherme Cabral

    2002-12-01

    The intracranial aneurysms of the posterior circulation have been reported between 5 and 10% of all cerebral aneurysms and the aneurysms of the anterior inferior cerebellar artery (AICA) are considered rare, can cause cerebello pontine angle (CPA) syndrome with or without subarachnoid hemorrhage. Since 1948 few cases were described in the literature. We report on a 33 year-old female patient with subarachnoid hemorrhage due to sacular aneurysm of the left AICA. She was submitted to clipage of the aneurysm without complications.

  5. Truncal ataxia from infarction involving the inferior olivary nucleus.

    PubMed

    Park, Jae Hyun; Ryoo, Sookyung; Moon, So Young; Seo, Sand Won; Na, Duk L

    2012-08-01

    Truncal ataxia in medullary infarction may be caused by involvement of the lateral part of the medulla; however, truncal ataxia in infarction involving the inferior olivary nucleus (ION) has received comparatively little attention. We report a patient with truncal ataxia due to medial medullary infarction located in the ION. A lesion in the ION could produce a contralateral truncal ataxia due to increased inhibitory input to the contralesional vestibular nucleus from the contralesional flocculus.

  6. Bruxism elicited by inferior alveolar nerve injury: a case report.

    PubMed

    Melis, Marcello; Coiana, Carlo; Secci, Simona

    2012-02-01

    The aim of this case report is to describe the history of a patient who received an injury to the right inferior alveolar nerve after placement of a dental implant, with bruxism noted afterward. The symptoms were managed by the use of an occlusal appliance worn at night and occasionally during the day, associated with increased awareness of parafunction during the day to reduce muscle pain and fatigue. Paresthesia of the teeth, gingiva, and lower lip persisted but were reduced during appliance use.

  7. Limb-specific representation for reaching in the posterior parietal cortex.

    PubMed

    Chang, Steve W C; Dickinson, Anthony R; Snyder, Lawrence H

    2008-06-11

    To reach for something we see, the brain must integrate the target location with the limb to be used for reaching. Neuronal activity in the parietal reach region (PRR) located in the posterior parietal cortex represents targets for reaching. Does this representation depend on the limb to be used? We found a continuum of limb-dependent and limb-independent responses: some neurons represented targets for movements of either limb, whereas others represented only contralateral-limb targets. Only a few cells represented ipsilateral-limb targets. Furthermore, these representations were not dependent on preferred direction. Additional experiments provide evidence that the PRR is specifically involved in contralateral-limb movements: firing rates are correlated with contralateral- but not ipsilateral-limb reaction times. The current study therefore provides novel evidence that the PRR operates as a limb-dependent stage that lies further along the sensory-motor transformation for visually guided reaching than previously expected.

  8. Contralateral neglect induced by right posterior parietal rTMS in healthy subjects.

    PubMed

    Fierro, B; Brighina, F; Oliveri, M; Piazza, A; La Bua, V; Buffa, D; Bisiach, E

    2000-05-15

    We applied repetitive transcranial magnetic stimulation (rTMS) in order to induce interference on visuo-spatial perception in 11 healthy subjects. Subjects performed a visuo-spatial task requiring judgements about the symmetry of prebisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 50 ms on a computer-monitor. Performance was examined in basal condition and during rTMS trains of 10 stimuli at 25 Hz, delivered through a focal coil over right or left posterior parietal cortex (P5 and P6 sites) and triggered synchronously with visual stimulus. Randomly intermixed sham rTMS trains were employed to control for non-specific effects. Right parietal rTMS induced a significant rightward bias in symmetry judgements as compared with basal and sham rTMS conditions. No differences emerged between other conditions.

  9. Complementary roles for primate frontal and parietal cortex in guarding working memory from distractor stimuli.

    PubMed

    Jacob, Simon Nikolas; Nieder, Andreas

    2014-07-02

    Prefrontal cortex (PFC) and posterior parietal cortex are important for maintaining behaviorally relevant information in working memory. Here, we challenge the commonly held view that suppression of distractors by PFC neurons is the main mechanism underlying the filtering of task-irrelevant information. We recorded single-unit activity from PFC and the ventral intraparietal area (VIP) of monkeys trained to resist distracting stimuli in a delayed-match-to-numerosity task. Surprisingly, PFC neurons preferentially encoded distractors during their presentation. Shortly after this interference, however, PFC neurons restored target information, which predicted correct behavioral decisions. In contrast, most VIP neurons only encoded target numerosities throughout the trial. Representation of target information in VIP was the earliest and most reliable neuronal correlate of behavior. Our data suggest that distracting stimuli can be bypassed by storing and retrieving target information, emphasizing active maintenance processes during working memory with complementary functions for frontal and parietal cortex in controlling memory content.

  10. Acute parietal lobe infarction presenting as Gerstmann's syndrome and cognitive decline mimicking senile dementia.

    PubMed

    Chen, Tien-Yu; Chen, Chun-Yen; Yen, Che-Hung; Kuo, Shin-Chang; Yeh, Yi-Wei; Chang, Serena; Huang, San-Yuan

    2013-01-01

    Gerstmann's syndrome encompasses the tetrad of finger agnosia, agraphia, acalculia, and right-left confusion. An elderly man with a history of several cardiovascular diseases was initially brought to the psychiatric outpatient department by his family because of worsening of recent memory, executive function, and mixed anxious-depressive mood. Gerstmann's syndrome without obvious motor function impairment and dementia-like features could be observed at first. Emergent brain computed tomography scan revealed new left-middle cerebral artery infarction over the left posterior parietal lobe. This case reminds us that acute cerebral infarction involving the parietal lobe may present as Gerstmann's syndrome accompanied by cognitive decline mimicking dementia. As a result, emergent organic workups should be arranged, especially for elderly patients at high risk for cerebral vascular accident.

  11. Acute parietal lobe infarction presenting as Gerstmann’s syndrome and cognitive decline mimicking senile dementia

    PubMed Central

    Chen, Tien-Yu; Chen, Chun-Yen; Yen, Che-Hung; Kuo, Shin-Chang; Yeh, Yi-Wei; Chang, Serena; Huang, San-Yuan

    2013-01-01

    Gerstmann’s syndrome encompasses the tetrad of finger agnosia, agraphia, acalculia, and right-left confusion. An elderly man with a history of several cardiovascular diseases was initially brought to the psychiatric outpatient department by his family because of worsening of recent memory, executive function, and mixed anxious-depressive mood. Gerstmann’s syndrome without obvious motor function impairment and dementia-like features could be observed at first. Emergent brain computed tomography scan revealed new left-middle cerebral artery infarction over the left posterior parietal lobe. This case reminds us that acute cerebral infarction involving the parietal lobe may present as Gerstmann’s syndrome accompanied by cognitive decline mimicking dementia. As a result, emergent organic workups should be arranged, especially for elderly patients at high risk for cerebral vascular accident. PMID:23847420

  12. Psychic tonus, body schema and the parietal lobes: a multiple lesion case analysis.

    PubMed

    Braun, C M J; Desjardins, S; Gaudelet, S; Guimond, A

    2007-01-01

    The psychic tonus model (Braun and colleagues, 1999, 2002, 2003, 2006) states that the left hemisphere is a "booster" of internal experience and behavior in general, and that the right hemisphere is a "dampener". Twenty-five patients with a "positive" extreme disturbance of body schema (somatoparaphrenia) and 37 patients with a "negative" disturbance of body schema (autotopagnosia or Gerstmann's syndrome), all following a unilateral parietal lesion, were found in the literature and were analyzed to test predictions from Braun's "psychic tonus" model. As expected, patients with a positive syndrome had a right hemisphere lesion significantly more frequently, and those with a negative syndrome had a left hemisphere lesion significantly more frequently. Thus the psychic tonus model of hemispheric specialization, previously supported with regard to psychomotor baseline, libido, talkativeness, memory, auditory and visual perceptual tonus, now incorporates the tonus of representation of the body (body schema) in the parietal lobes.

  13. Representation of the Numerosity ‘zero’ in the Parietal Cortex of the Monkey

    PubMed Central

    Okuyama, Sumito; Kuki, Toshinobu; Mushiake, Hajime

    2015-01-01

    Zero is a fundamental concept in mathematics and modern science. Empty sets are considered a precursor of the concept of numerosity zero and a part of numerical continuum. How is numerosity zero (the absence of visual items) represented in the primate cortex? To address this question, we trained monkeys to perform numerical operations including numerosity zero. Here we show a group of neurons in the posterior parietal cortex of the monkey activated in response to numerosity ‘zero’. ‘Zero’ neurons are classified into exclusive and continuous types; the exclusive type discretely encodes numerical absence and the continuous type encodes numerical absence as a part of a numerical continuum. “Numerosity-zero” neurons enhance behavioral discrimination of not only zero numerosity but also non-zero numerosities. Representation of numerosity zero in the parietal cortex may be a precursor of non-verbal concept of zero in primates. PMID:25989598

  14. Direct control of visual perception with phase-specific modulation of posterior parietal cortex.

    PubMed

    Jaegle, Andrew; Ro, Tony

    2014-02-01

    We examined the causal relationship between the phase of alpha oscillations (9-12 Hz) and conscious visual perception using rhythmic TMS (rTMS) while simultaneously recording EEG activity. rTMS of posterior parietal cortex at an alpha frequency (10 Hz), but not occipital or sham rTMS, both entrained the phase of subsequent alpha oscillatory activity and produced a phase-dependent change on subsequent visual perception, with lower discrimination accuracy for targets presented at one phase of the alpha oscillatory waveform than for targets presented at the opposite phase. By extrinsically manipulating the phase of alpha before stimulus presentation, we provide direct evidence that the neural circuitry in the parietal cortex involved with generating alpha oscillations plays a causal role in determining whether or not a visual stimulus is successfully perceived.

  15. Unique and shared roles of the posterior parietal and dorsolateral prefrontal cortex in cognitive functions

    PubMed Central

    Katsuki, Fumi; Constantinidis, Christos

    2012-01-01

    The dorsolateral prefrontal cortex (PFC) and posterior parietal cortex (PPC) are two parts of a broader brain network involved in the control of cognitive functions such as working-memory, spatial attention, and decision-making. The two areas share many functional properties and exhibit similar patterns of activation during the execution of mental operations. However, neurophysiological experiments in non-human primates have also documented subtle differences, revealing functional specialization within the fronto-parietal network. These differences include the ability of the PFC to influence memory performance, attention allocation, and motor responses to a greater extent, and to resist interference by distracting stimuli. In recent years, distinct cellular and anatomical differences have been identified, offering insights into how functional specialization is achieved. This article reviews the common functions and functional differences between the PFC and PPC, and their underlying mechanisms. PMID:22563310

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

    PubMed Central

    Shikauchi, Yumi; Ishii, Shin

    2015-01-01

    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. PMID:26631641

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

    PubMed

    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.

  18. Optic ataxia: from Balint’s syndrome to the parietal reach region

    PubMed Central

    Andersen, Richard A.; Andersen, Kristen N.; Hwang, EunJung; Hauschild, Markus

    2014-01-01

    Optic ataxia is a high order deficit in reaching to visual goals that occurs with posterior parietal cortex (PPC) lesions. It is a component of Balint’s syndrome that also includes attentional and gaze disorders. Aspects of optic ataxia are misreaching in the contralesional visual field, difficulty preshaping the hand for grasping, and an inability to correct reaches online. Recent research in non-human primates (NHPs) suggests that many aspects of Balint’s syndrome and optic ataxia are a result of damage to specific functional modules for reaching, saccades, grasp, attention, and state estimation. The deficits from large lesions in humans are likely composite effects from damage to combinations of these functional modules. Interactions between these modules, either within posterior parietal cortex or downstream within frontal cortex, may account for more complex behaviors such as hand-eye coordination and reach-to-grasp. PMID:24607223

  19. Differential diagnosis of bilateral parietal abnormalities in I-123 IMP SPECT imaging

    SciTech Connect

    Kuwabara, Y.; Ichiya, Y.; Otsuka, M.; Tahara, T.; Fukumura, T.; Gunasekera, R.; Masuda, K. )

    1990-12-01

    This report discusses the clinical significance of bilateral parietal abnormalities on I-123 IMP SPECT imaging in 158 patients with cerebral disorders. This pattern was seen in 15 out of 21 patients with Alzheimer's disease; it was also seen in 4 out of 5 patients with Parkinson's disease with dementia, in 3 out of 17 patients with vascular dementia, in 1 out of 36 patients with cerebral infarction without dementia, in 1 out of 2 patients with hypoglycemia, and in 1 out of 2 patients with CO intoxication. Detection of bilateral parietal abnormalities is a useful finding in the diagnosis of Alzheimer's disease, but one should keep in mind that other cerebral disorders may also show a similar pattern with I-123 IMP SPECT imaging.

  20. Bayesian approach to non-inferiority trials for normal means.

    PubMed

    Gamalo, M Amper; Wu, Rui; Tiwari, Ram C

    2016-02-01

    Regulatory framework recommends that novel statistical methodology for analyzing trial results parallels the frequentist strategy, e.g. the new method must protect type-I error and arrive at a similar conclusion. Keeping these in mind, we construct a Bayesian approach for non-inferiority trials with normal response. A non-informative prior is assumed for the mean response of the experimental treatment and Jeffrey's prior for its corresponding variance when it is unknown. The posteriors of the mean response and variance of the treatment in historical trials are then assumed as priors for its corresponding parameters in the current trial, where that treatment serves as the active control. From these priors, a Bayesian decision criterion is derived to determine whether the experimental treatment is non-inferior to the active control. This criterion is evaluated and compared with the frequentist method using simulation studies. Results show that both Bayesian and frequentist approaches perform alike, but the Bayesian approach has a higher power when the variances are unknown. Both methods also arrive at the same conclusion of non-inferiority when applied on two real datasets. A major advantage of the proposed Bayesian approach lies in its ability to provide posterior probabilities for varying effect sizes of the experimental treatment over the active control.

  1. Abducens nerve palsy due to inferior petrosal sinus thrombosis.

    PubMed

    Mittal, Shivam Om; Siddiqui, Junaid; Katirji, Bashar

    2017-02-24

    Isolated unilateral abducens nerve palsy is usually due to ischemia, trauma or neoplasm. Dorello's canal is the space between the petrous apex and superolateral portion of the clivus, bound superiorly by Gruber's ligament. The abducens nerve travels with inferior petrosal sinus (IPS) though the Dorello's canal before entering the cavernous sinus. A 31-year-old man presented with neck pain, and binocular horizontal diplopia, worse looking towards left and at distance. He had a history of intravenous drug abuse but no history of hypertension or diabetes. On examination, he had complete left 6th nerve palsy with normal fundi, pupils, and other cranial nerves. Methicillin-resistant Staphylococcus aureus bacteremia was detected with naïve tricuspid valve endocarditis and multiple septic emboli to lungs with infarcts. His cerebrospinal fluid was normal. MRI of the brain was normal. MRV of head and neck showed thrombosis of the left internal jugular vein, left sigmoid sinus and left inferior petrosal sinus with normal cavernous sinus and no evidence of mastoiditis. He was treated with broad spectrum antibiotics. He was not anticoagulated for fear of pulmonary hemorrhage from pulmonary infarcts. Although cerebral venous sinus thrombosis commonly presents with elevated intracranial pressure, isolated ipsilateral 6th nerve palsy from its compression in Dorello's canal due to thrombosis of the ipsilateral inferior petrosal sinus is extremely rare. To our knowledge, only two patients have been reported with isolated abducens palsy due to IPS thrombosis; one caused by septic emboli and the other developed it during IPS cortisol level sampling.

  2. Inferior vestibular neuritis in a fighter pilot: a case report.

    PubMed

    Xie, Su Jiang; Jia, Hong Bo; Xu, Po; Zheng, Ying Juan

    2013-06-01

    Spatial disorientation in airplane pilots is a leading factor in many fatal flying accidents. Spatial orientation is the product of integrative inputs from the proprioceptive, vestibular, and visual systems. One condition that can lead to sudden pilot incapacitation in flight is vestibular neuritis. Vestibular neuritis is commonly diagnosed by a finding of unilateral vestibular failure, such as a loss of caloric response. However, because caloric response testing reflects the function of only the superior part of the vestibular nerve, it cannot detect cases of neuritis in only the inferior part of the nerve. We describe the case of a Chinese naval command fighter pilot who exhibited symptoms suggestive of vestibular neuritis but whose caloric response test results were normal. Further testing showed a unilateral loss of vestibular evoked myogenic potentials (VEMPs). We believe that this pilot had pure inferior nerve vestibular neuritis. VEMP testing plays a major role in the diagnosis of inferior nerve vestibular neuritis in pilots. We also discuss this issue in terms of aeromedical concerns.

  3. Inferior hip dislocation after falling from height: A case report

    PubMed Central

    Tekin, Ali Çağrı; Çabuk, Haluk; Büyükkurt, Cem Dinçay; Dedeoğlu, Süleyman Semih; İmren, Yunus; Gürbüz, Hakan

    2016-01-01

    Introduction Traumatic inferior hip dislocation is the least common of all hip dislocations. Adult inferior hip dislocations usually occur after high-energy trauma, very few cases are reported without fracture. Presentation of case A 26-year-old female was brought to the emergency department with severe pain in the left hip, impaired posture and restricted movement following a fall from 15 m height. The hip joint was fixed in 90° flexion, 15° abduction, and 20° external rotation. No neurovascular impairment was determined. On radiologic examination, a left ischial type inferior hip dislocation was detected. Hemorrhagic shock which developed due to acute blood loss to thoracic and abdominal cavity and patient died at third hour after she was brought to the hospital. Discussion Traumatic hip dislocations have high morbidity and mortality rates due to multiple organ damage, primarily of the extremities, chest and abdomen. In the treatment of traumatic hip dislocation, closed reduction is recommended through muscle relaxation under general anesthesia or sedation. This procedure should be applied before any intervention for concomitant extremity injuries. A detailed evaluation on emergency presentation, a multi-disciplinary approach and early diagnosis with the rapid application of imaging methods could be life-saving for such patients. PMID:27058153

  4. [Inferior vertical nystagmus: is magnetic resonance imaging mandatory?].

    PubMed

    Esteban-Sánchez, Jonathan; Rueda-Marcos, Almudena; Sanz-Fernández, Ricardo; Martín-Sanz, Eduardo

    2016-02-01

    Introduccion. La aparicion de un nistagmo vertical inferior clasicamente obliga a descartar una patologia vascular o de la union craneocervical mediante resonancia magnetica (RM). Estudios recientes demuestran una baja rentabilidad de esta prueba, ya que sugieren que este signo oculomotor puede tener una causa vestibular periferica, sobre todo cuando el paciente presenta un vertigo posicional paroxistico benigno (VPPB) del canal semicircular superior. Objetivo. Comprobar la rentabilidad de la RM en una poblacion de pacientes con nistagmo de posicion vertical inferior. Pacientes y metodos. Estudio retrospectivo de 42 pacientes consecutivos a los que se les realizo una historia clinica, exploracion fisica, y pruebas vestibulares caloricas y rotatorias. A todos ellos se les practico una RM craneal y cervical. Resultados. El 52% de los pacientes con nistagmo de posicion vertical inferior presentaba una clinica y exploracion fisica compatibles con VPPB del canal semicircular superior. La RM fue normal en un 67%, un 26% mostraba datos de espondilopatia y un 5% de microangiopatia cerebral no relacionados con la clinica del paciente. La prevalencia de malformacion de Arnold-Chiari de tipo I fue de un 9% en la poblacion estudiada, sin que nadie tuviera un antecedente reciente de VPPB. Los resultados obtenidos en las pruebas complementarias vestibulares no aportaron informacion adicional para llegar a un diagnostico etiologico. Conclusion. En los pacientes con un VPPB, la RM craneal y las pruebas vestibulares tienen una baja rentabilidad diagnostica, y se debe evaluar la necesidad real de esta prueba con el contexto clinico.

  5. Intraosseous schwannoma originating in inferior alveolar nerve: a case report.

    PubMed

    Suga, Kenichiro; Ogane, Satoru; Muramatsu, Kyotaro; Ohata, Hitoshi; Uchiyama, Takeshi; Takano, Nobuo; Shibahara, Takahiko; Eguchi, Jun; Murakami, Satoshi; Matsuzaka, Kenichi

    2013-01-01

    Schwannomas (neurilemmomas) are benign neoplasms derived from Schwann cells of the neurilemma and appear most frequently on the auditory nerve or peripheral nerves of the skin. They arise in the oral and maxillofacial region infrequently, and very rarely in the center of the jaw. We herein present a case of a rare mandibular intraosseous schwannoma derived from the main trunk of the inferior alveolar nerve in a 33-year-old man. Fusiform expansion in the mandibular canal was observed and a mass showing the target sign in the mandibular canal was confirmed on T2-weighted and Gd contrastenhanced T1-weighted MRI. Based on these findings, an inferior alveolar nerve-derived schwannoma or other benign nervous system neoplasm was diagnosed. A buccal side cortical bone flap in the mandibular molar region was removed to expose the mass, which was then peeled away from the nerve fibers and completely removed. Some inferior alveolar nerve fibers that were connected to the mass were removed at the same time, but the remaining nerve fiber bundle was preserved. Histopathology confirmed the diagnosis of a schwannoma with Antoni type A and Antoni type B regions. Although the patient experienced extremely mild paresthesia in the skin over the mental region and mental foramen at immediately after surgery, this had almost entirely disappeared at 7 years and 4 months later, and there has been no tumor recurrence.

  6. Dynamic activation of frontal, parietal, and sensory regions underlying anticipatory visual spatial attention.

    PubMed

    Simpson, Gregory V; Weber, Darren L; Dale, Corby L; Pantazis, Dimitrios; Bressler, Steven L; Leahy, Richard M; Luks, Tracy L

    2011-09-28

    Although it is well established that multiple frontal, parietal, and occipital regions in humans are involved in anticipatory deployment of visual spatial attention, less is known about the electrophysiological signals in each region across multiple subsecond periods of attentional deployment. We used MEG measures of cortical stimulus-locked, signal-averaged (event-related field) activity during a task in which a symbolic cue directed covert attention to the relevant location on each trial. Direction-specific attention effects occurred in different cortical regions for each of multiple time periods during the delay between the cue and imperative stimulus. A sequence of activation from V1/V2 to extrastriate, parietal, and frontal regions occurred within 110 ms after cue, possibly related to extraction of cue meaning. Direction-specific activations ∼300 ms after cue in frontal eye field (FEF), lateral intraparietal area (LIP), and cuneus support early covert targeting of the cued location. This was followed by coactivation of a frontal-parietal system [superior frontal gyrus (SFG), middle frontal gyrus (MFG), LIP, anterior intraparietal sulcus (IPSa)] that may coordinate the transition from targeting the cued location to sustained deployment of attention to both space and feature in the last period. The last period involved direction-specific activity in parietal regions and both dorsal and ventral sensory regions [LIP, IPSa, ventral IPS, lateral occipital region, and fusiform gyrus], which was accompanied by activation that was not direction specific in right hemisphere frontal regions (FEF, SFG, MFG). Behavioral performance corresponded with the magnitude of attention-related activity in different brain regions at each time period during deployment. The results add to the emerging electrophysiological characterization of different cortical networks that operate during anticipatory deployment of visual spatial attention.

  7. Decision and action planning signals in human posterior parietal cortex during delayed perceptual choices.

    PubMed

    Tosoni, Annalisa; Corbetta, Maurizio; Calluso, Cinzia; Committeri, Giorgia; Pezzulo, Giovanni; Romani, G L; Galati, Gaspare

    2014-04-01

    During simple perceptual decisions, sensorimotor neurons in monkey fronto-parietal cortex represent a decision variable that guides the transformation of sensory evidence into a motor response, supporting the view that mechanisms for decision-making are closely embedded within sensorimotor structures. Within these structures, however, decision signals can be dissociated from motor signals, thus indicating that sensorimotor neurons can play multiple and independent roles in decision-making and action selection/planning. Here we used functional magnetic resonance imaging to examine whether response-selective human brain areas encode signals for decision-making or action planning during a task requiring an arbitrary association between face pictures (male vs. female) and specific actions (saccadic eye vs. hand pointing movements). The stimuli were gradually unmasked to stretch the time necessary for decision, thus maximising the temporal separation between decision and action planning. Decision-related signals were measured in parietal and motor/premotor regions showing a preference for the planning/execution of saccadic or pointing movements. In a parietal reach region, decision-related signals were specific for the stimulus category associated with its preferred pointing response. By contrast, a saccade-selective posterior intraparietal sulcus region carried decision-related signals even when the task required a pointing response. Consistent signals were observed in the motor/premotor cortex. Whole-brain analyses indicated that, in our task, the most reliable decision signals were found in the same neural regions involved in response selection. However, decision- and action-related signals within these regions can be dissociated. Differences between the parietal reach region and posterior intraparietal sulcus plausibly depend on their functional specificity rather than on the task structure.

  8. Differential coupling of visual cortex with default or frontal-parietal network based on goals.

    PubMed

    Chadick, James Z; Gazzaley, Adam

    2011-05-29

    The relationship between top-down enhancement and suppression of sensory cortical activity and large-scale neural networks remains unclear. Functional connectivity analysis of human functional magnetic resonance imaging data revealed that visual cortical areas that selectively process relevant information are functionally connected with the frontal-parietal network, whereas those that process irrelevant information are simultaneously coupled with the default network. This indicates that sensory cortical regions are differentially and dynamically coupled with distinct networks on the basis of task goals.

  9. Distinct parietal sites mediate the influences of mood, arousal, and their interaction on human recognition memory.

    PubMed

    Greene, Ciara M; Flannery, Oliver; Soto, David

    2014-12-01

    The two dimensions of emotion, mood valence and arousal, have independent effects on recognition memory. At present, however, it is not clear how those effects are reflected in the human brain. Previous research in this area has generally dealt with memory for emotionally valenced or arousing stimuli, but the manner in which interacting mood and arousal states modulate responses in memory substrates remains poorly understood. We investigated memory for emotionally neutral items while independently manipulating mood valence and arousal state by means of music exposure. Four emotional conditions were created: positive mood/high arousal, positive mood/low arousal, negative mood/high arousal, and negative mood/low arousal. We observed distinct effects of mood valence and arousal in parietal substrates of recognition memory. Positive mood increased activity in ventral posterior parietal cortex (PPC) and orbitofrontal cortex, whereas arousal condition modulated activity in dorsal PPC and the posterior cingulate. An interaction between valence and arousal was observed in left ventral PPC, notably in a parietal area distinct from the those identified for the main effects, with a stronger effect of mood on recognition memory responses here under conditions of relative high versus low arousal. We interpreted the PPC activations in terms of the attention-to-memory hypothesis: Increased arousal may lead to increased top-down control of memory, and hence dorsal PPC activation, whereas positive mood valence may result in increased activity in ventral PPC regions associated with bottom-up attention to memory. These findings indicate that distinct parietal sites mediate the influences of mood, arousal, and their interplay during recognition memory.

  10. Overlapping parietal activity in memory and perception: evidence for the attention to memory model.

    PubMed

    Cabeza, Roberto; Mazuz, Yonatan S; Stokes, Jared; Kragel, James E; Woldorff, Marty G; Ciaramelli, Elisa; Olson, Ingrid R; Moscovitch, Morris

    2011-11-01

    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 output or the retrieval cue. This model also hypothesizes that the attentional functions of DPC and VPC are similar for memory and perception. To investigate this last hypothesis, we scanned participants with event-related fMRI whereas they performed memory and perception tasks, each comprising an orienting phase (top-down attention) and a detection phase (bottom-up attention). The study yielded two main findings. First, consistent with the AtoM model, orienting-related activity for memory and perception overlapped in DPC, whereas detection-related activity for memory and perception overlapped in VPC. The DPC overlap was greater in the left intraparietal sulcus, and the VPC overlap in the left TPJ. Around overlapping areas, there were differences in the spatial distribution of memory and perception activations, which were consistent with trends reported in the literature. Second, both DPC and VPC showed stronger connectivity with medial-temporal lobe during the memory task and with visual cortex during the perception task. These findings suggest that, during memory tasks, some parietal regions mediate similar attentional control processes to those involved in perception tasks (orienting in DPC vs. detection in VPC), although on different types of information (mnemonic vs. sensory).

  11. Differential Functionality of Right and Left Parietal Activity in Controlling a Motor Vehicle

    PubMed Central

    Brooks, Justin R.; Garcia, Javier O.; Kerick, Scott E.; Vettel, Jean M.

    2016-01-01

    Driving a motor vehicle is an inherently complex task that requires robust control to avoid catastrophic accidents. Drivers must maintain their vehicle in the middle of the travel lane to avoid high speed collisions with other traffic. Interestingly, while a vehicle’s lane deviation (LD) is critical, studies have demonstrated that heading error (HE) is one of the primary variables drivers use to determine a steering response, which directly controls the position of the vehicle in the lane. In this study, we examined how the brain represents the dichotomy between control/response parameters (heading, reaction time (RT), and steering wheel corrections) and task-critical parameters (LD). Specifically, we examined electroencephalography (EEG) alpha band power (8–13 Hz) from estimated sources in right and left parietal regions, and related this activity to four metrics of driving performance. Our results demonstrate differential task involvement between the two hemispheres: right parietal activity was most closely related to LD, whereas left parietal activity was most closely related to HE, RT and steering responses. Furthermore, HE, RT and steering wheel corrections increased over the duration of the experiment while LD did not. Collectively, our results suggest that the brain uses differential monitoring and control strategies in the right and left parietal regions to control a motor vehicle. Our results suggest that the regulation of this control changes over time while maintaining critical task performance. These results are interpreted in two complementary theoretical frameworks: the uncontrolled manifold and compensatory control theories. The central tenet of these frameworks permits performance variability in parameters (i.e., HE, RT and steering) so far as it does not interfere with critical task execution (i.e., LD). Our results extend the existing research by demonstrating potential neural substrates for this phenomenon which may serve as potential targets

  12. The somatotopic organization of cytoarchitectonic areas on the human parietal operculum.

    PubMed

    Eickhoff, Simon B; Grefkes, Christian; Zilles, Karl; Fink, Gereon R

    2007-08-01

    The secondary somatosensory cortex (SII) of nonhuman primates is located on the parietal operculum. In the monkey, electrophysiological and connectivity tracing studies as well as histological investigations provide converging evidence for 3 distinct cortical areas (SII, PV, and VS) within this region, each of which contains a complete somatotopic map. Although the equivalency of the parietal operculum as the location of SII between humans and nonhuman primates is undisputed, the internal organization of the human SII region is still largely unknown. Based on their topography, we have previously argued that the cytoarchitectonic areas OP 1, OP 4, and OP 3 may constitute the human homologues of areas SII, PV, and VS, respectively. To test this hypothesis, we here examined (using functional magnetic resonance imaging) the somatotopic organization of the human parietal operculum by applying tactile stimulation to the skin at 4 different locations on either side of the body (face, hands, trunk, and legs). The locations of the resulting activation foci were then compared with the cytoarchitectonic maps of this region. Data analysis revealed 2 somatotopic body representations on the lateral operculum in areas OP 1 and OP 4. The functional border between these 2 body maps was defined by a mirror reversal in the somatotopic arrangement and coincided with the cytoarchitectonically defined border between these 2 areas. This somatotopic arrangement closely matches that described for SII and PV in nonhuman primates. The data also suggested a third somatotopic map located deeper inside the Sylvian fissure in area OP 3. Based on the observed topographic arrangement and their functional response characteristics, we conclude that cytoarchitectonic areas OP1, OP 4, and OP 3 on the human parietal operculum constitute the human homologues of primate areas SII, PV, and VS, respectively.

  13. Human posterior parietal cortex encodes the movement goal in a pro-/anti-reach task

    PubMed Central

    Gertz, Hanna

    2015-01-01

    Previous research on reach planning in humans has implicated a frontoparietal network, including the precuneus (PCu), a putative human homolog of the monkey parietal reach region (PRR), and the dorsal premotor cortex (PMd). Using a pro-/anti-reach task, electrophysiological studies in monkeys have demonstrated that the movement goal rather than the location of the visual cue is encoded in PRR and PMd. However, if only the effector but not the movement goal is specified (underspecified condition), the PRR and PMd have been shown to represent all potential movement goals. In this functional magnetic resonance imaging study, we investigated whether the human PCu and PMd likewise encode the movement goal, and whether these reach-related areas also engage in situations with underspecified compared with specified movement goals. By using a pro-/anti-reach task, we spatially dissociated the location of the visual cue from the location of the movement goal. In the specified conditions, pro- and anti-reaches activated similar parietal and premotor areas. In the PCu contralateral to the moving arm, we found directionally selective activation fixed to the movement goal. In the underspecified conditions, we observed activation in reach-related areas of the posterior parietal cortex, including PCu. However, the activation was substantially weaker in parietal areas and lacking in PMd. Our results suggest that human PCu encodes the movement goal rather than the location of the visual cue if the movement goal is specified and even engages in situations when only the visual cue but not the movement goal is defined. PMID:25904714

  14. Distinguishing Intentions from Desires: Contributions of the Frontal and Parietal Lobes

    ERIC Educational Resources Information Center

    Chiavarino, Claudia; Apperly, Ian A.; Humphreys, Glyn W.

    2010-01-01

    The ability to represent desires and intentions as two distinct mental states was investigated in patients with parietal (N = 8) and frontal (N = 6) lesions and in age-matched controls (N = 7). A task was used where the satisfaction of the desire and the fulfilment of the intention did not co-vary and were manipulated in a 2 x 2 set. In two…

  15. Fronto-Parietal gray matter and white matter efficiency differentially predict intelligence in males and females.

    PubMed

    Ryman, Sephira G; Yeo, Ronald A; Witkiewitz, Katie; Vakhtin, Andrei A; van den Heuvel, Martijn; de Reus, Marcel; Flores, Ranee A; Wertz, Christopher R; Jung, Rex E

    2016-11-01

    While there are minimal sex differences in overall intelligence, males, on average, have larger total brain volume and corresponding regional brain volumes compared to females, measures that are consistently related to intelligence. Limited research has examined which other brain characteristics may differentially contribute to intelligence in females to facilitate equal performance on intelligence measures. Recent reports of sex differences in the neural characteristics of the brain further highlight the need to differentiate how the structural neural characteristics relate to intellectual ability in males and females. The current study utilized a graph network approach in conjunction with structural equation modeling to examine potential sex differences in the relationship between white matter efficiency, fronto-parietal gray matter volume, and general cognitive ability (GCA). Participants were healthy adults (n = 244) who completed a battery of cognitive testing and underwent structural neuroimaging. Results indicated that in males, a latent factor of fronto-parietal gray matter was significantly related to GCA when controlling for total gray matter volume. In females, white matter efficiency and total gray matter volume were significantly related to GCA, with no specificity of the fronto-parietal gray matter factor over and above total gray matter volume. This work highlights that different neural characteristics across males and females may contribute to performance on intelligence measures. Hum Brain Mapp 37:4006-4016, 2016. © 2016 Wiley Periodicals, Inc.

  16. [Blocks neuron activity parietal cortex monkey brain, connected with achievement of intermediate goals of multistage behavior].

    PubMed

    Filatova, E V; Orlov, A A; Afanas'ev, S V

    2014-07-01

    The single unit activity of the monkey parietal cortex was studied during the task of alternative spatial selection. Simultaneously activities of 6--10 neurons were recorded. It was revealed that tonic impulse activity of parietal cortex neurons forms blocks. The structure of blocks reflects the structure of behavioral task and related to the achievement of interim targets in performing of be- havioral task. Earlier the formation of similar blocks of tonic activity was shown for unit activity of putamen and prefrontal cortex. Thus the data obtained evidence in favor of that grouping of tonic activity is not an individual feature of some structures but has more general character most likely typical and for other brain areas. Generally it shows that nerve control of complex much component behavior is accomplished in segments by formation of separate blocks in neuronal activity. These blocks are related to individual groups of actions which in combination lead to a final goal--performance of behavioral task in a whole. Key words: unit activity, behavior, monkey, parietal cortex.

  17. [Signal transduction and intracellular recruitment of gastric proton pump in the parietal cell].

    PubMed

    Urushidani, T; Nagao, T

    1997-12-01

    The parietal cell has three types of activating receptors for acid secretion on its basolateral membrane, i.e., histamine H2, acetylcholine M3, and gastrin CCKB. Activation of acid secretion is achieved by two concomitant functional changes namely: (i) tubulovesicles fuse with the apical secretory membrane, thus recruiting functional pumps to the expanded microvillar surface, and (ii) the apical membrane acquires a permeability to KCl. The major path for parietal cell stimulation is via H2-receptor-mediated adenylate cyclase and elevation of cAMP to activate protein kinase A (PKA), which phosphorylates key effector proteins, e.g., ezrin, a membrane-cytoskeletal linker, apical Cl- or K(+)-channels. Ca2+ is liberated from intracellular stores by IP3, which in turn is the result of M3-, CCKB-, or possibly H2-coupled activation of phospholipase C. The resulting protein kinase C activation may have both inhibitory and excitatory roles. Elevated Ca2+ activates calmodulin-dependent kinases, e.g., calmodulin kinase II and myosin light chain kinase, that could promote vesicular motor activity. Ezrin is considered to play a main role in the vesicular transport system of the parietal cell. The regulation might be conducted through the phosphorylation of the molecule to modify its property to interact with the cytoskeletal components, membranes or membrane proteins.

  18. The parietal cortex in sensemaking: the dissociation of multiple types of spatial information.

    PubMed

    Sun, Yanlong; Wang, Hongbin

    2013-01-01

    According to the data-frame theory, sensemaking is a macrocognitive process in which people try to make sense of or explain their observations by processing a number of explanatory structures called frames until the observations and frames become congruent. During the sensemaking process, the parietal cortex has been implicated in various cognitive tasks for the functions related to spatial and temporal information processing, mathematical thinking, and spatial attention. In particular, the parietal cortex plays important roles by extracting multiple representations of magnitudes at the early stages of perceptual analysis. By a series of neural network simulations, we demonstrate that the dissociation of different types of spatial information can start early with a rather similar structure (i.e., sensitivity on a common metric), but accurate representations require specific goal-directed top-down controls due to the interference in selective attention. Our results suggest that the roles of the parietal cortex rely on the hierarchical organization of multiple spatial representations and their interactions. The dissociation and interference between different types of spatial information are essentially the result of the competition at different levels of abstraction.

  19. Tolerance of the skull to blunt ballistic temporo-parietal impact.

    PubMed

    Raymond, David; Van Ee, Chris; Crawford, Gregory; Bir, Cynthia

    2009-11-13

    Less-lethal ballistic projectiles are used by police personnel to temporarily incapacitate suspects. While the frequency of these impacts to the head is low, they account for more serious injuries than impacts to any other body region. As a result, there is an urgent need to assess the tolerance of the head to such impacts. The focus of this study was to investigate the tolerance of the temporo-parietal skull to blunt ballistic impact and establish injury criteria for risk assessment. Seven unembalmed isolated cadaver heads were subjected to fourteen impacts. Specimens were instrumented with a nine-accelerometer array as well as strain gages surrounding the impact site. Impacts were performed with a 38 mm instrumented projectile at velocities ranging from 18 to 37 m/s. CT images and autopsies were performed to document resulting fractures. Peak fracture force for the seven resulting fractures was 5633+/-2095 N. Peak deformation for fracture-producing impacts was 7.8+/-3.2 mm. The blunt criterion (BC), peak force and principal strain were determined to be the best predictors of depressed comminuted fractures. Temporo-parietal tolerance levels were consistent with previous studies. An initial force tolerance level of 2346 N is established for the temporo-parietal region for blunt ballistic impact with a 38 mm diameter impactor.

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

    PubMed Central

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

    2016-01-01

    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. PMID:27452715

  1. Transcranial direct current stimulation (tDCS) of the parietal cortex leads to increased false recognition.

    PubMed

    Pergolizzi, Denise; Chua, Elizabeth F

    2015-01-01

    A robust finding is that brain activity in the lateral posterior parietal cortex (PPC) correlates with successful recognition. Here we test whether the PPC has a causal role in memory retrieval using transcranial direct current stimulation (tDCS). Participants were given a modified version of the Deese-Roediger-McDermott (DRM) paradigm, a well-established method for producing false recognition with high confidence. In Experiment 1, false recognition was significantly greater for active compared to sham tDCS when the anode was placed over left parietal cortex (CP3) and the cathode over right parietal cortex (CP4). These findings were replicated in Experiment 2, with both anode CP3/cathode CP4 and anode CP4/cathode CP3 active stimulation leading to greater false recognition. Differences also emerged, with anode CP4/cathode CP3 active stimulation leading to greater hits. Our findings support the proposal that the lateral PPC plays a causal role in episodic memory retrieval and can lead to enhanced subjective aspects of memory.

  2. Perceptual and cognitive visual functions of parietal and temporal cortices in the cat.

    PubMed

    Lomber, S G; Payne, B R; Cornwell, P; Long, K D

    1996-01-01

    We used reversible cooling deactivation to compare the functions of cortices lining the middle suprasylvian (MS) sulcus and forming the ventral portion of the posterior suprasylvian (vPS) gyrus. A battery of attentional, motion and mnemonic processing tasks were used and performance was examined during deactivation of each region. The results show a clear dissociation of functions. Deactivation of MS cortex resulted in profound deficits on a visual orienting task and on the discrimination of direction of motion, whereas deactivation of vPS cortex severely impaired both retention and learning of novel and overlearned object discriminations. In addition, deactivation of either MS or vPS cortex impaired discrimination of learned patterns when components of the patterns were in motion, whereas only deactivation of vPS cortex impaired the discrimination when all components were static. Together, these results show that a region of parietal cortex contributes to the processing of visual motion and to attentional processes, whereas a region of temporal cortex contributes to the learning and recognition of three-dimensional objects and two-dimensional patterns. This functional dissociation is linked to differences in underlying visual pathways, which have many features in common with the parietal and temporal visual processing streams previously identified in monkeys and humans. Furthermore, the broad similarity in neural operations carried out in parietal and temporal cortices of cats, monkeys and humans suggests the existence of a common plan for cortical processing machinery within mammals with well developed cerebral cortices.

  3. Drug-resistant parietal epilepsy: polymorphic ictal semiology does not preclude good post-surgical outcome.

    PubMed

    Francione, Stefano; Liava, Alexandra; Mai, Roberto; Nobili, Lino; Sartori, Ivana; Tassi, Laura; Scarpa, Pina; Cardinale, Francesco; Castana, Laura; Cossu, Massimo; Lo Russo, Giorgio

    2015-03-01

    We investigated the anatomo-electro-clinical features and clinical outcome of surgical resections strictly confined to the parietal lobe in 40 consecutive patients who received surgery for pharmacoresistant seizures. The population was subcategorized into a paediatric (11 subjects; mean age at surgery: 7.2+/-3.7 years) and an adult group (29 patients; mean age at surgery: 30+/-10.8 years). The paediatric group more frequently exhibited personal antecedents, neurological impairment, high seizure frequency, and dysplastic lesions. Nonetheless, compared with adults, children had better outcome and more frequently reached definitive drug discontinuation after surgery. After a mean follow-up of 9.4 years (range: 3.1-16.7), 30 subjects (75%) were classified as Engel Class I. The presence of multiple types of aura in the same patient, as well as a high incidence of secondary generalization, represented a characteristic feature of parietal seizures and did not correlate negatively with surgical outcome. A total resection of the epileptogenic zone and a localizing/regional interictal EEG were statistically significant predictive factors of outcome. Intracerebral investigation, performed in 55% of cases, contributed to complete tailored resections of the epileptogenic area and determination of prognosis. Frequent subjective manifestations of parietal lobe seizures, such as vertiginous, cephalic and visual-moving sensations, underscore their potential misdiagnosis as non-epileptic events.

  4. Synchronization patterns suggest different functional organization in parietal reach region and dorsal premotor cortex.

    PubMed

    Chakrabarti, Shubhodeep; Martinez-Vazquez, Pablo; Gail, Alexander

    2014-12-15

    The parietal reach region (PRR) and dorsal premotor cortex (PMd) form part of the fronto-parietal reach network. While neural selectivity profiles of single-cell activity in these areas can be remarkably similar, other data suggest that both areas serve different computational functions in visually guided reaching. Here we test the hypothesis that different neural functional organizations characterized by different neural synchronization patterns might be underlying the putatively different functional roles. We use cross-correlation analysis on single-unit activity (SUA) and multiunit activity (MUA) to determine the prevalence of synchronized neural ensembles within each area. First, we reliably find synchronization in PRR but not in PMd. Second, we demonstrate that synchronization in PRR is present in different cognitive states, including "idle" states prior to task-relevant instructions and without neural tuning. Third, we show that local field potentials (LFPs) in PRR but not PMd are characterized by an increased power and spike field coherence in the beta frequency range (12-30 Hz), further indicating stronger synchrony in PRR compared with PMd. Finally, we show that neurons with similar tuning properties tend to be correlated in their random spike rate fluctuations in PRR but not in PMd. Our data support the idea that PRR and PMd, despite striking similarity in single-cell tuning properties, are characterized by unequal local functional organization, which likely reflects different network architectures to support different functional roles within the fronto-parietal reach network.

  5. Effect of histamine on regional cerebral blood flow of the parietal lobe in rats.

    PubMed

    Yang, Peng-Bo; Chen, Xin-Lin; Zhao, Jian-Jun; Zhang, Jian-Shui; Zhang, Jun-Feng; Tian, Yu-Mei; Liu, Yong

    2010-09-01

    Histamine is a powerful modulator that regulates blood vessels and blood flow. The effect of histamine on the extracortical vessels has been well described, while much less is known about the effect of histamine on intracortical vessels. In this study, we investigated the effect of histamine on regional cerebral blood flow in rat parietal lobe with laser Doppler flowmetry. The pharmacological characteristics of distinct ways (intracerebroventricular injection, intraperitoneal injection, and cranial window infusion) in applying histamine to the brain were also obtained and compared. Histamine applied in three ways all produced a decrease of rCBF in parietal lobe in a concentration-dependent manner. Cranial window infusion was the most effective way and intraperitoneal injection of L-histidine was the most ineffective, although it is a simple and applied way. To determine which type of receptor takes part in the vessel contraction induced by histamine, H1 receptor antagonist, diphenhydramine, and H2 receptor antagonist, cimetidine, were applied, respectively, before histamine administration. When the injection of cimetidine was conducted in advance, histamine still resulted in a decrease of infusion amount; while the injection of diphenhydramine was conducted in advance, the infusion of blood amount wasn't changed. These findings indicated that histamine could result in a reduction of rCBF in the rat parietal lobe and this effect of histamine may attribute partly to its combination with H1 receptor.

  6. Temporal accuracy and variability in the left and right posterior parietal cortex.

    PubMed

    Vicario, C M; Martino, D; Koch, G

    2013-08-15

    Several brain-imaging and lesion studies have suggested a role for the posterior parietal cortex (PPC) in computing interval-timing tasks. PPC also seems to have a key role in modulating visuospatial mechanisms, which are known to affect temporal performance. By applying transcranial direct current stimulation (tDCS) over the left and right PPC, we aimed to modulate timing ability performance in healthy humans performing a cognitively controlled timing task. In two separate experiments we compared time-processing abilities of two groups of healthy adults submitted to anodal, cathodal or sham tDCS over right or left PPC, by employing a supra-second time reproduction task. Cathodal stimulation over the right PPC affected temporal accuracy by leading participants to overestimate time intervals. Moreover, when applied to the left PPC, it reduced variability in reproducing temporal intervals. No effect was reported for anodal stimulation. These results expand current knowledge on the role of the parietal cortex on temporal processing. We provide evidence that the parietal cortex of both hemispheres is involved in temporal processing by acting on distinct components of timing performance such as accuracy and variability.

  7. Distributed patterns of occipito-parietal functional connectivity predict the precision of visual working memory.

    PubMed

    Galeano Weber, Elena M; Hahn, Tim; Hilger, Kirsten; Fiebach, Christian J

    2017-02-01

    Limitations in visual working memory (WM) quality (i.e., WM precision) may depend on perceptual and attentional limitations during stimulus encoding, thereby affecting WM capacity. WM encoding relies on the interaction between sensory processing systems and fronto-parietal 'control' regions, and differences in the quality of this interaction are a plausible source of individual differences in WM capacity. Accordingly, we hypothesized that the coupling between perceptual and attentional systems affects the quality of WM encoding. We combined fMRI connectivity analysis with behavioral modeling by fitting a variable precision and fixed capacity model to the performance data obtained while participants performed a visual delayed continuous response WM task. We quantified functional connectivity during WM encoding between occipital and parietal brain regions activated during both perception and WM encoding, as determined using a conjunction of two independent experiments. The multivariate pattern of voxel-wise inter-areal functional connectivity significantly predicted WM performance, most specifically the mean of WM precision but not the individual number of items that could be stored in memory. In particular, higher occipito-parietal connectivity was associated with higher behavioral mean precision. These results are consistent with a network perspective of WM capacity, suggesting that the efficiency of information flow between perceptual and attentional neural systems is a critical determinant of limitations in WM quality.

  8. Behavioral cartography of visual functions in cat parietal cortex: areal and laminar dissociations.

    PubMed

    Lomber, S G

    2001-01-01

    The purpose of this review is to: (1) compare and contrast the relative contributions that the four principle regions in cat extrastriate parietal cortex make to a battery of visual tasks which require motion, spatial, or attentional processing; and (2) examine the laminar parcellation of visual behaviors within one of these parietal regions which mediates multiple visual behaviors. We examined a battery of visual tasks presumed to be mediated by parietal cortex, including direction of motion, differential motion, and landmark discriminations, and visual orienting to moving stimuli. As a control, we also examined performance on form (pattern and object) recognition tasks mediated by the temporal processing stream. The four regions of parietal cortex we examined included the: middle suprasylvian (MS) gyrus (area 7), anterior middle suprasylvian (aMS) sulcus (AMLS, ALLS), posterior middle suprasylvian (pMS) sulcus (PMLS, PLLS), and the dorsal posterior suprasylvian (dPS) gyrus (area 21a). The contributions made to each of the six different behavioral tasks was examined before, during, and after reversible cooling deactivation of each cortical area. Deactivation of pMS sulcal cortex resulted in deficits on all four tasks that required motion, spatial or attentional processing. Deactivation of aMS sulcal cortex resulted in deficits on only tasks that required motion processing. Deactivation of neither aMS nor pMS sulcal cortex yielded any deficits on the form recognition tasks. In contrast, deactivation of dPS cortex only produced deficits on the form recognition tasks. This finding confirmed our early hypothesis that dPS cortex is a key component of the temporal, and not the parietal, processing stream. Regardless of the task, no deficits were identified on any of the six tasks during deactivation of the MS gyrus. We then more closely examined pMS sulcal cortex to determine if its multiple functions could be dissociated on a laminar level. We found that cooling

  9. Modality specificity in the cerebro-cerebellar neurocircuitry during working memory.

    PubMed

    Ng, H B Tommy; Kao, K-L Cathy; Chan, Y C; Chew, Effie; Chuang, K H; Chen, S H Annabel

    2016-05-15

    Previous studies have suggested cerebro-cerebellar circuitry in working memory. The present fMRI study aims to distinguish differential cerebro-cerebellar activation patterns in verbal and visual working memory, and employs a quantitative analysis to deterimine lateralization of the activation patterns observed. Consistent with Chen and Desmond (2005a,b) predictions, verbal working memory activated a cerebro-cerebellar circuitry that comprised left-lateralized language-related brain regions including the inferior frontal and posterior parietal areas, and subcortically, right-lateralized superior (lobule VI) and inferior cerebellar (lobule VIIIA/VIIB) areas. In contrast, a distributed network of bilateral inferior frontal and inferior temporal areas, and bilateral superior (lobule VI) and inferior (lobule VIIB) cerebellar areas, was recruited during visual working memory. Results of the study verified that a distinct cross cerebro-cerebellar circuitry underlies verbal working memory. However, a neural circuitry involving specialized brain areas in bilateral neocortical and bilateral cerebellar hemispheres subserving visual working memory is observed. Findings are discussed in the light of current models of working memory and data from related neuroimaging studies.

  10. Variation in left posterior parietal-motor cortex interhemispheric facilitation following right parietal continuous theta-burst stimulation in healthy adults.

    PubMed

    Killington, Christopher; Barr, Christopher; Loetscher, Tobias; Bradnam, Lynley V

    2016-08-25

    Spatial neglect is modeled on an imbalance of interhemispheric inhibition (IHI); however evidence is emerging that it may not explain neglect in all cases. The aim of this study was to investigate the IHI imbalance model of visual neglect in healthy adults, using paired pulse transcranial magnetic stimulation to probe excitability of projections from posterior parietal cortex (PPC) to contralateral primary motor cortex (M1) bilaterally. Motor-evoked potentials (MEPs) were recorded from the first dorsal interossei and facilitation was determined as ratio of conditioned to non-conditioned MEP amplitude. A laterality index reflecting the balance of excitability between the two hemispheres was calculated. A temporal order judgment task (TOJ) assessed visual attention. Continuous theta-burst stimulation was used to transiently suppress right parietal cortex activity and the effect on laterality and judgment task measured, along with associations between baseline and post stimulation measures. Stimulation had conflicting results on laterality, with most participants demonstrating an effect in the negative direction with no decrement in the TOJ task. Correlation analysis suggests a strong association between laterality direction and degree of facilitation of left PPC-to right M1 following stimulation (r=.902), with larger MEP facilitation at baseline demonstrating greater reduction (r=-.908). Findings indicate there was relative balance between the cortices at baseline but right PPC suppression did not evoke left PPC facilitation in most participants, contrary to the IHI imbalance model. Left M1 facilitation prior to stimulation may predict an individual's response to continuous theta-burst stimulation of right PPC.

  11. [Changes in the ultrastructure of the stomach mucous membrane parietal cells caused by inhibitors of hydrochloric acid secretion].

    PubMed

    Dondukova, G V; Morozov, I A

    2002-01-01

    The study of the action of phamotidine and omeprazol on the stomach parietal cells in patients with duodenal ulcer has shown that phamotidin results in changes of secretory membrane of the parietal cells increasing its secretory potential while omeprazol reduces energetic metabolism of the lining cell by the impact on its mitochondrial apparatus. Both in children and adults with duodenal ulcer more developed mitochondrial cell activity was found after omeprazol treatment.

  12. An Enlarged Parietal Foramen in the Late Archaic Xujiayao 11 Neurocranium from Northern China, and Rare Anomalies among Pleistocene Homo

    PubMed Central

    Xing, Song

    2013-01-01

    We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual’s age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans. PMID:23527224

  13. Synchronization of fronto-parietal beta and theta networks as a signature of visual awareness in neglect.

    PubMed

    Yordanova, Juliana; Kolev, Vasil; Verleger, Rolf; Heide, Wolfgang; Grumbt, Michael; Schürmann, Martin

    2017-02-01

    In the neglect syndrome, the perceptual deficit for contra-lesional hemi-space is increasingly viewed as a dysfunction of fronto-parietal cortical networks, the disruption of which has been described in neuroanatomical and hemodynamic studies. Here we exploit the superior temporal resolution of electroencephalography (EEG) to study dynamic transient connectivity of fronto-parietal circuits at early stages of visual perception in neglect. As reflected by inter-regional phase synchronization in a full-field attention task, two functionally distinct fronto-parietal networks, in beta (15-25Hz) and theta (4-8Hz) frequency bands, were related to stimulus discrimination within the first 200 ms of visual processing. Neglect pathology was specifically associated with significant suppressions of both beta and theta networks engaging right parietal regions. These connectivity abnormalities occurred in a pattern that was distinctly different from what was observed in right-hemisphere lesion patients without neglect. Also, both beta and theta abnormalities contributed additively to visual awareness decrease, quantified in the Behavioural Inattention Test. These results provide evidence for the impairment of fast dynamic fronto-parietal interactions during early stages of visual processing in neglect pathology. Also, they reveal that different modes of fronto-parietal dysfunction contribute independently to deficits in visual awareness at the behavioural level.

  14. Altered neural basis of the reality processing and its relation to cognitive insight in schizophrenia.

    PubMed

    Lee, Jung Suk; Chun, Ji Won; Lee, Sang-Hoon; Kim, Eosu; Lee, Seung-Koo; Kim, Jae-Jin

    2015-01-01

    It has been reported that reality evaluation and recognition are impaired in patients with schizophrenia and these impairments are related to the severity of psychotic symptoms. The current study aimed to investigate the neural basis of impairments in reality evaluation and recognition and their relationships with cognitive insight in schizophrenia. During functional magnetic resonance imaging, 20 patients with schizophrenia and 20 healthy controls performed a set of reality evaluation and recognition tasks, in which subjects judged whether scenes in a series of drawings were real or unreal and whether they were familiar or novel. During reality evaluation, patients showed decreased activity in various regions including the inferior parietal lobule, retrosplenial cortex and parahippocampal gyrus, compared with controls. Particularly, parahippocampal gyrus activity was correlated with the severity of positive symptoms in patients. During recognition, patients also exhibited decreased activity in various regions, including the dorsolateral prefrontal cortex, inferior parietal lobule and posterior cingulate cortex. Particularly, inferior parietal lobule activity and posterior cingulate cortex activity were correlated with cognitive insight in patients. These findings provide evidence that neural impairments in reality evaluation and recognition are related to psychotic symptoms. Anomalous appraisal of context by dysfunctions in the context network may contribute to impairments in the reality processing in schizophrenia, and abnormal declarative memory processes may be involved in cognitive insight in patients with schizophrenia.

  15. Anesthetic technique for inferior alveolar nerve block: a new approach

    PubMed Central

    PALTI, Dafna Geller; de ALMEIDA, Cristiane Machado; RODRIGUES, Antonio de Castro; ANDREO, Jesus Carlos; LIMA, José Eduardo Oliveira

    2011-01-01

    Background Effective pain control in Dentistry may be achieved by local anesthetic techniques. The success of the anesthetic technique in mandibular structures depends on the proximity of the needle tip to the mandibular foramen at the moment of anesthetic injection into the pterygomandibular region. Two techniques are available to reach the inferior alveolar nerve where it enters the mandibular canal, namely indirect and direct; these techniques differ in the number of movements required. Data demonstrate that the indirect technique is considered ineffective in 15% of cases and the direct technique in 1329% of cases. Objective Objective: The aim of this study was to describe an alternative technique for inferior alveolar nerve block using several anatomical points for reference, simplifying the procedure and enabling greater success and a more rapid learning curve. Materials and Methods A total of 193 mandibles (146 with permanent dentition and 47 with primary dentition) from dry skulls were used to establish a relationship between the teeth and the mandibular foramen. By using two wires, the first passing through the mesiobuccal groove and middle point of the mesial slope of the distolingual cusp of the primary second molar or permanent first molar (right side), and the second following the oclusal plane (left side), a line can be achieved whose projection coincides with the left mandibular foramen. Results The obtained data showed correlation in 82.88% of cases using the permanent first molar, and in 93.62% of cases using the primary second molar. Conclusion This method is potentially effective for inferior alveolar nerve block, especially in Pediatric Dentistry. PMID:21437463

  16. Inferior epigastric artery: Surface anatomy, prevention and management of injury.

    PubMed

    Wong, Clare; Merkur, Harry

    2016-04-01

    The anatomical position of the inferior epigastric artery (IEA) subjects it to risk of injury during abdominal procedures that are close to the artery, such as laparoscopic trocar insertion, insertion of intra-abdominal drains, Tenckhoff(®) catheter (peritoneal dialysis catheter) and paracentesis. This article aims to raise the awareness of the anatomical variations of the course of the IEA in relation to abdominal landmarks in order to define a safer zone for laparoscopic ancillary trocar placement. Methods of managing the IEA injury as well as techniques to minimise the risk of injury to the IEA are reviewed and discussed.

  17. CT fluoroscopic guided insertion of inferior vena cava filters.

    PubMed

    Ignotus, P; Wetton, C; Berry, J

    2006-03-01

    The value and use of inferior vena cava (IVC) filters is well documented and has been growing since the first reported filter placement in 1973 and the first percutaneous insertion in 1982. Access routes now include both jugular veins, both ante-cubital veins and both femoral veins. However, all insertions require some form of imaging, usually fluoroscopy, to identify the location of the filter with respect to the IVC and the renal veins. We describe two cases where the patients' weight was significantly greater than the weight limit of the angiography table, necessitating insertion under CT fluoroscopic guidance.

  18. A Novel Technique for Inferior Vena Cava Filter Extraction

    SciTech Connect

    Johnston, Edward William Rowe, Luke Michael Morgan; Brookes, Jocelyn; Raja, Jowad; Hague, Julian

    2013-05-02

    Inferior vena cava (IVC) filters are used to protect against pulmonary embolism in high-risk patients. Whilst the insertion of retrievable IVC filters is gaining popularity, a proportion of such devices cannot be removed using standard techniques. We describe a novel approach for IVC filter removal that involves snaring the filter superiorly along with the use of flexible forceps or laser devices to dissect the filter struts from the caval wall. This technique has used to successfully treat three patients without complications in whom standard techniques failed.

  19. Inferior ST-Elevation Myocardial Infarction Associated with Takotsubo Cardiomyopathy

    PubMed Central

    Koeth, Oliver; Zeymer, Uwe; Schiele, Rudolf; Zahn, Ralf

    2010-01-01

    Takotsubo cardiomyopathy (TCM) is usually characterized by transient left ventricular apical ballooning. Due to the clinical symptoms which include chest pain, electrocardiographic changes, and elevated myocardial markers, Takotsubo cardiomyopathy is frequently mimicking ST-elevation myocardial infarction in the absence of a significant coronary artery disease. Otherwise an acute occlusion of the left anterior descending coronary artery can produce a typical Takotsubo contraction pattern. ST-elevation myocardial infarction (STEMI) is frequently associated with emotional stress, but to date no cases of STEMI triggering TCM have been reported. We describe a case of a female patient with inferior ST-elevation myocardial infarction complicated by TCM. PMID:20811565

  20. Inferior alveolar nerve paresthesia relieved by microscopic endodontic treatment.

    PubMed

    Yatsuhashi, Takaaki; Nakagawa, Kan-Ichi; Matsumoto, Miho; Kasahara, Masataka; Igarashi, Tomoko; Ichinohe, Tatsuya; Kaneko, Yuzuru

    2003-11-01

    We experienced two cases of inferior alveolar nerve paresthesia caused by root canal medicaments, which were successfully relieved by microscopic endodontic treatment. In the first case, the paresthesia might have been attributable to infiltration of calcium hydroxide into the mandibular canal through the root canals of the mandibular left second molar tooth. In the second case, the paresthesia might have been attributable to infiltration of paraformaldehyde through the root canals of the mandibular right second molar tooth. The paresthesia was relieved in both cases by repetitive microscopic endodontic irrigation using physiological saline solution in combination with oral vitamin B12 and adenosine triphosphate.

  1. Duplicate inferior vena cava filters: more is not always better.

    PubMed

    Katyal, Anup; Javed, Muhammad Ali

    2016-01-01

    Duplication of the inferior vena cava (IVC) has been reported in literature. This achieves clinical significance in the setting of lower extremity venous thromboembolism with a contraindication for anticoagulation. We describe a case of lower extremity deep vein thrombosis with duplicate IVC. Anticoagulation was contraindicated in this case leading to successful treatment with double IVC filters. We conducted a PubMed search for all current English language published literature, where filters were placed in the presence of duplicate IVC. We suggest that patients with deep vein thrombosis should have an accurate assessment of venous anatomy before IVC filter placement. Duplication of IVC, although rare, should be considered as this has management implications.

  2. Transcriptomes of purified gastric ECL and parietal cells: identification of a novel pathway regulating acid secretion.

    PubMed

    Lambrecht, Nils W G; Yakubov, Iskandar; Zer, Cindy; Sachs, George

    2006-03-13

    The gastric entero-chromaffin-like (ECL) cell plays a key regulatory role in peripheral regulation of acid secretion due to the release of histamine that stimulates acid secretion by the parietal cell. Studies in intact animals, gastric glands, and isolated cells after short-term culture have shown expression of stimulatory CCK2 and PAC1 and inhibitory SST2 and Gal1 receptors as well as histidine decarboxylase. However, the pattern of its gene expression as a neuroendocrine cell has not been explored. Comparison of gene expression by 95% pure ECL cells obtained by density gradient, elutriation, and fluorescence-assisted cell sorting with isolates of the intact fundic gastric epithelium (i.e., "subtractive hybridization") identified a variety of additional expressed gene families characteristic of this neuroendocrine cell. These include genes 1) involved in neuropeptide synthesis and secretory vesicle exocytosis, 2) involved in control of inflammation, 3) implicated in healing of the epithelium, 4) encoding inhibitory Gi protein-coupled receptors, 5) playing a role in neuroendocrine regulation of food intake, and 6) encoding proteins likely involved in maintenance of circadian rhythm, in addition to the ECL cell-specific genes histidine decarboxylase and monoamine transporter. Particularly, the inhibitory apelin receptor gene, APJ, was highly expressed in the ECL cell preparation. Because parietal cells express apelin, immunohistochemical and functional studies showed that there is an inhibitory feed back loop between the parietal and ECL cell during gastrin stimulation, providing evidence for a novel pathway of downregulation of acid secretion due to interaction between these two cell types.

  3. Observational learning of new movement sequences is reflected in fronto-parietal coherence.

    PubMed

    van der Helden, Jurjen; van Schie, Hein T; Rombouts, Christiaan

    2010-12-31

    Mankind is unique in her ability for observational learning, i.e. the transmission of acquired knowledge and behavioral repertoire through observation of others' actions. In the present study we used electrophysiological measures to investigate brain mechanisms of observational learning. Analysis investigated the possible functional coupling between occipital (alpha) and motor (mu) rhythms operating in the 10 Hz frequency range for translating "seeing" into "doing". Subjects observed movement sequences consisting of six consecutive left or right hand button presses directed at one of two target-buttons for subsequent imitation. Each movement sequence was presented four times, intervened by short pause intervals for sequence rehearsal. During a control task subjects observed the same movement sequences without a requirement for subsequent reproduction. Although both alpha and mu rhythms desynchronized during the imitation task relative to the control task, modulations in alpha and mu power were found to be largely independent from each other over time, arguing against a functional coupling of alpha and mu generators during observational learning. This independence was furthermore reflected in the absence of coherence between occipital and motor electrodes overlaying alpha and mu generators. Instead, coherence analysis revealed a pair of symmetric fronto-parietal networks, one over the left and one over the right hemisphere, reflecting stronger coherence during observation of movements than during pauses. Individual differences in fronto-parietal coherence were furthermore found to predict imitation accuracy. The properties of these networks, i.e. their fronto-parietal distribution, their ipsilateral organization and their sensitivity to the observation of movements, match closely with the known properties of the mirror neuron system (MNS) as studied in the macaque brain. These results indicate a functional dissociation between higher order areas for observational

  4. From perception to action: temporal integrative functions of prefrontal and parietal neurons.

    PubMed

    Quintana, J; Fuster, J M

    1999-01-01

    The dorsolateral prefrontal cortex (DPFC) and the posterior parietal cortex (PPC) are anatomically and functionally interconnected, and have been implicated in working memory and the preparation for behavioral action. To substantiate those functions at the neuronal level, we designed a visuomotor task that dissociated the perceptual and executive aspects of the perception-action cycle in both space and time. In that task, the trial-initiating cue (a color) indicated with different degrees of certainty the direction of the correct manual response 12 s later. We recorded extracellular activity from 258 prefrontal and 223 parietal units in two monkeys performing the task. In the DPFC, some units (memory cells) were attuned to the color of the cue, independent of the response-direction it connoted. Their discharge tended to diminish in the course of the delay between cue and response. In contrast, few color-related units were found in PPC, and these did not show decreasing patterns of delay activity. Other units in both cortices (set cells) were attuned to response-direction and tended to accelerate their firing in anticipation of the response and in proportion to the predictability of its direction. A third group of units was related to the determinacy of the act; their firing was attuned to the certainty with which the animal could predict the correct response, whatever its direction. Cells of the three types were found closely intermingled histologically. These findings further support and define the role of DPFC in executive functions and in the temporal closure of the perception-action cycle. The findings also agree with the involvement of PPC in spatial aspects of visuomotor behavior, and add a temporal integrative dimension to that involvement. Together, the results provide physiological evidence for the role of a prefrontal-parietal network in the integration of perception with action across time.

  5. Inefficient Chronic Activation of Parietal Cells in Ae2a,b−/− Mice

    PubMed Central

    Recalde, Sergio; Muruzábal, Francisco; Looije, Norbert; Kunne, Cindy; Burrell, María A.; Sáez, Elena; Martínez-Ansó, Eduardo; Salas, January T.; Mardones, Pablo; Prieto, Jesús; Medina, Juan F.; Elferink, Ronald P.J. Oude

    2006-01-01

    In parietal cells, basolateral Ae2 Cl−/HCO3− exchanger (Slc4a2) appears to compensate for luminal H+ pumping while providing Cl− for apical secretion. In mouse and rat, mRNA variants Ae2a, Ae2b1, Ae2b2, and Ae2c2 are all found in most tissues (although the latter at very low levels), whereas Ae2c1 is restricted to the stomach. We studied the acid secretory function of gastric mucosa in mice with targeted disruption of Ae2a, Ae2b1, and Ae2b2 (but not Ae2c) isoforms. In the oxyntic mucosa of Ae2a,b−/− mice, total Ae2 protein was nearly undetectable, indicating low gastric expression of the Ae2c isoforms. In Ae2a,b−/− mice basal acid secretion was normal, whereas carbachol/histamine-stimulated acid secretion was impaired by 70%. These animals showed increased serum gastrin levels and hyperplasia of G cells. Immunohistochemistry and electron microscopy revealed baseline activation of parietal cells with fusion of intracellular H+/K+-ATPase-containing vesicles with the apical membrane and degenerative changes (but not substantial apoptosis) in a subpopulation of these cells. Increased expression of proliferating cell nuclear antigen in the oxyntic glands suggested enhanced Ae2a,b−/− parietal cell turnover. These data reveal a critical role of Ae2a-Ae2b1-Ae2b2 isoforms in stimulated gastric acid secretion whereas residual Ae2c isoforms could account to a limited extent for basal acid secretion. PMID:16816370

  6. Using inferior vena cava filters to prevent pulmonary embolism

    PubMed Central

    Chung, John; Owen, Richard J.T.

    2008-01-01

    OBJECTIVE To review the evidence for using inferior vena cava (IVC) filters to prevent pulmonary embolism (PE) in high-risk patients. QUALITY OF EVIDENCE Ovid MEDLINE was searched from 1966 to 2006 for all English-language papers on IVC filters. Evidence was graded according to the 3-level classification system. Most evidence found was level II. MAIN MESSAGE Inferior vena cava filters are used to prevent PE in patients with contraindications to, complications of, or failure of anticoagulation therapy and patients with extensive free-floating thrombi or residual thrombi following massive PE. Current evidence indicates that IVC filters are largely effective; breakthrough PE occurs in only 0% to 6.2% of cases. Contraindications to implantation of IVC filters include lack of venous access, caval occlusion, uncorrectable coagulopathy, and sepsis. Complications include misplacement or embolization of the filter, vascular injury or thrombosis, pneumothorax, and air emboli. Recurrent PE, IVC thrombosis, filter migration, filter fracture, or penetration of the caval wall sometimes occur with long-term use. CONCLUSION When used appropriately, IVC filters are a safe and effective method of preventing PE. Using retrievable filters might reduce long-term complications. PMID:18208955

  7. [LGM inferior vena cava filters--observation of 79 patients].

    PubMed

    Hajduk, B; Tomkowski, W; Fijałkowska, A; Oniszh, K; Małek, G; Wawrzyńska, L; Radomyski, A; Filipecki, S; Torbicki, A

    2000-11-01

    The aim of the study was to assess effectiveness and safety of the LGM inferior vena cava (IVC) filters in patients with venous thromboembolic disease. In the Department of Internal Medicine of Institute of Tuberculosis and Lung Diseases in Warsaw 79 LGM IVC filters have been inserted since 1993. Indications for filters placement were as follows: recurrent pulmonary embolism (pe) despite anticoagulation--17 patients (pts), severe bleeding complications of thrombolytic or anticoagulant therapy--11 pts, contraindications for thrombolytic and/or anticoagulant treatment--5 pts, massive pe--14 pts, chronic thromboembolic-major vessel pulmonary hypertension (CTEPH)--30 pts, extensive deep vein thrombosis of lower limbs or vena cava inferior in patients with urgent indications for surgery--24 pts. Each filter placement was preceded by cavography. The diagnostic procedures (mainly ultrasonography) were performed after 3-6 and 12 months in the first year then once yearly during follow-up period. Oral anticoagulants (OA) or low-molecular-weight heparins (LMWH) were instituted in the majority of patients. 58 patients are still alive, 21 patients died. Only two non-fatal episodes of recurrent pe were documented. Other complications were rare and insignificant. We have not observed excess rate of recurrent deep venous thrombosis nor thrombosis at the filter site. The LGM IVC filters are effective and safe in such selectively chosen group of patients.

  8. Monopolar intracochlear pulse trains selectively activate the inferior colliculus.

    PubMed

    Schoenecker, Matthew C; Bonham, Ben H; Stakhovskaya, Olga A; Snyder, Russell L; Leake, Patricia A

    2012-10-01

    Previous cochlear implant studies using isolated electrical stimulus pulses in animal models have reported that intracochlear monopolar stimulus configurations elicit broad extents of neuronal activation within the central auditory system-much broader than the activation patterns produced by bipolar electrode pairs or acoustic tones. However, psychophysical and speech reception studies that use sustained pulse trains do not show clear performance differences for monopolar versus bipolar configurations. To test whether monopolar intracochlear stimulation can produce selective activation of the inferior colliculus, we measured activation widths along the tonotopic axis of the inferior colliculus for acoustic tones and 1,000-pulse/s electrical pulse trains in guinea pigs and cats. Electrical pulse trains were presented using an array of 6-12 stimulating electrodes distributed longitudinally on a space-filling silicone carrier positioned in the scala tympani of the cochlea. We found that for monopolar, bipolar, and acoustic stimuli, activation widths were significantly narrower for sustained responses than for the transient response to the stimulus onset. Furthermore, monopolar and bipolar stimuli elicited similar activation widths when compared at stimulus levels that produced similar peak spike rates. Surprisingly, we found that in guinea pigs, monopolar and bipolar stimuli produced narrower sustained activation than 60 dB sound pressure level acoustic tones when compared at stimulus levels that produced similar peak spike rates. Therefore, we conclude that intracochlear electrical stimulation using monopolar pulse trains can produce activation patterns that are at least as selective as bipolar or acoustic stimulation.

  9. Seeing without the occipito-parietal cortex: Simultagnosia as a shrinkage of the attentional visual field.

    PubMed

    Michel, François; Henaff, Marie-Anne

    2004-01-01

    Following bi-parietal lesions patient AT showed a severe inability to relocate her attention within a visual field which perimetry proved to be near-normal. An experimental approach with tasks testing visuo-spatial attention demonstrated a shrinkage of A.T.'s attentional visual field. With her visual attention narrowed to a kind of functional tunnel vision, the patient exhibited simultanagnosia (Wolpert, 1924), a symptom previously described in 1909 by Balint under the label of Psychic paralysis of "Gaze". In striking contrast AT showed an efficient and effortless perception of complex natural scenes, which, according to recent work in normal subjects, necessitate few if any attentional resources.

  10. Parietal atretic cephalocele: Associated cerebral anomalies identified by CT and MR imaging

    PubMed Central

    Siverino, Rita Olivia Anna; Attinà, Giancarlo; Chiaramonte, Rita; Milone, Pietro; Chiaramonte, Ignazio

    2015-01-01

    We describe a case of atretic cephalocele (AC) characterized by the presence of various cerebral anomalies of different midline structures. In our patient the presence of a parietal AC was associated with an embryonic position of the straight sinus, fenestration of the superior sagittal sinus, an abnormal insertion of the cerebellar tentorium with prominence of the superior cerebellar cistern and a septum pellucidum cyst. These findings, associated with AC, could lead to a worse prognosis with regard to neurodevelopmental milestones. This suggests that even if AC is a benign lesion, a complete evaluation of the brain structures should always be performed in these young patients. PMID:25963151

  11. Symptomatic Parietal Intradiploic Encephalocele—A Case Report and Literature Review

    PubMed Central

    Shi, Chen; Flores, Bruno; Fisher, Stephen; Barnett, Samuel L

    2017-01-01

    Encephalocele is a rare condition that consists of herniation of cerebral matter through openings of dura and skull. A majority of encephaloceles are congenital and manifest in childhood. We present a case of a 45-year-old man presenting with contralateral hemiparesis and found to have an extremely rare phenomenon of a symptomatic posttraumatic parietal intradiploic encephalocele (IE) manifesting 36 years following pediatric traumatic head injury. Computed tomography and magnetic resonance imaging confirmed herniation of brain tissue into the intradiploic space. Surgical treatment with reduction of the encephalocele achieved near resolution of preoperative hemiparesis on follow-up. The pathogenesis and a literature review of IE are discussed. PMID:28316901

  12. Parietal control of attentional guidance: the significance of sensory, motivational and motor factors

    PubMed Central

    Gottlieb, Jacqueline; Balan, Puiu; Oristaglio, Jeff; Suzuki, Mototaka

    2009-01-01

    The lateral intraparietal area (LIP), a portion of monkey posterior parietal cortex, has been implicated in spatial attention. We review recent evidence showing that LIP encodes a priority map of the external environment that specifies the momentary locus of attention and is activated in a variety of behavioral tasks. The priority map in LIP is shaped by task-specific motor, cognitive and motivational variables, the functional significance of which is not entirely understood. We suggest that these modulations represent teaching signals by which the brain learns to identify attentional priority to stimuli based on the task-specific associations between these stimuli, the required decision and expected outcome. PMID:18929673

  13. Forward Prediction in the Posterior Parietal Cortex and Dynamic Brain-Machine Interface

    PubMed Central

    Cui, He

    2016-01-01

    While remarkable progress has been made in brain-machine interfaces (BMIs) over the past two decades, it is still difficult to utilize neural signals to drive artificial actuators to produce predictive movements in response to dynamic stimuli. In contrast to naturalistic limb movements largely based on forward planning, brain-controlled neuroprosthetics mainly rely on feedback without prior trajectory formation. As an important sensorimotor interface integrating multisensory inputs and efference copy, the posterior parietal cortex (PPC) might play a proactive role in predictive motor control. Here it is proposed that predictive neural activity in PPC could be decoded to provide prosthetic control signals for guiding BMI systems in dynamic environments. PMID:27833537

  14. Injury of the Inferior Alveolar Nerve during Implant Placement: a Literature Review

    PubMed Central

    Wang, Hom-Lay; Sabalys, Gintautas

    2011-01-01

    ABSTRACT Objectives The purpose of present article was to review aetiological factors, mechanism, clinical symptoms, and diagnostic methods as well as to create treatment guidelines for the management of inferior alveolar nerve injury during dental implant placement. Material and Methods Literature was selected through a search of PubMed, Embase and Cochrane electronic databases. The keywords used for search were inferior alveolar nerve injury, inferior alveolar nerve injuries, inferior alveolar nerve injury implant, inferior alveolar nerve damage, inferior alveolar nerve paresthesia and inferior alveolar nerve repair. The search was restricted to English language articles, published from 1972 to November 2010. Additionally, a manual search in the major anatomy, dental implant, periodontal and oral surgery journals and books were performed. The publications there selected by including clinical, human anatomy and physiology studies. Results In total 136 literature sources were obtained and reviewed. Aetiological factors of inferior alveolar nerve injury, risk factors, mechanism, clinical sensory nerve examination methods, clinical symptoms and treatment were discussed. Guidelines were created to illustrate the methods used to prevent and manage inferior alveolar nerve injury before or after dental implant placement. Conclusions The damage of inferior alveolar nerve during the dental implant placement can be a serious complication. Clinician should recognise and exclude aetiological factors leading to nerve injury. Proper presurgery planning, timely diagnosis and treatment are the key to avoid nerve sensory disturbances management. PMID:24421983

  15. Individual variation in intentionality in the mind-wandering state is reflected in the integration of the default-mode, fronto-parietal, and limbic networks.

    PubMed

    Golchert, Johannes; Smallwood, Jonathan; Jefferies, Elizabeth; Seli, Paul; Huntenburg, Julia M; Liem, Franziskus; Lauckner, Mark E; Oligschläger, Sabine; Bernhardt, Boris C; Villringer, Arno; Margulies, Daniel S

    2017-02-01

    Mind-wandering has a controversial relationship with cognitive control. Existing psychological evidence supports the hypothesis that episodes of mind-wandering reflect a failure to constrain thinking to task-relevant material, as well the apparently alternative view that control can facilitate the expression of self-generated mental content. We assessed whether this apparent contradiction arises because of a failure to consider differences in the types of thoughts that occur during mind-wandering, and in particular, the associated level of intentionality. Using multi-modal magnetic resonance imaging (MRI) analysis, we examined the cortical organisation that underlies inter-individual differences in descriptions of the spontaneous or deliberate nature of mind-wandering. Cortical thickness, as well as functional connectivity analyses, implicated regions relevant to cognitive control and regions of the default-mode network for individuals who reported high rates of deliberate mind-wandering. In contrast, higher reports of spontaneous mind-wandering were associated with cortical thinning in parietal and posterior temporal regions in the left hemisphere (which are important in the control of cognition and attention) as well as heightened connectivity between the intraparietal sulcus and a region that spanned limbic and default-mode regions in the ventral inferior frontal gyrus. Finally, we observed a dissociation in the thickness of the retrosplenial cortex/lingual gyrus, with higher reports of spontaneous mind-wandering being associated with thickening in the left hemisphere, and higher repots of deliberate mind-wandering with thinning in the right hemisphere. These results suggest that the intentionality of the mind-wandering state depends on integration between the control and default-mode networks, with more deliberation being associated with greater integration between these systems. We conclude that one reason why mind-wandering has a controversial relationship

  16. Aneurysm in the anterior inferior cerebellar artery-posterior inferior cerebellar artery variant: Case report and review of literature

    PubMed Central

    Akhtar, Saad; Azeem, Abdul; Jiwani, Amyna; Javed, Gohar

    2016-01-01

    Introduction There are variations in the anatomy of the vertebrobasilar system amongst which the Anterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery (AICA-PICA) variant is thought to have a prevalence of 20–24% (based on retrospective studies). Despite this, aneurysms of the AICA-PICA variant are rare. We present a case of an AICA-PICA aneurysm and discuss its presentation and management, along with a review of literature. Presentation of case We describe the case of a 35 year old female who presented with signs of meningismus. On the basis of radiological imaging it was initially misdiagnosed as a thrombosed arteriovenous malformation (AVM). The patient was eventually discharged with a plan of interval imaging and interventional radiology (if required). The patient presented again with similar signs and symptoms. Re-evaluation of imaging revealed an aneurysm of the AICA-PICA variant which was managed surgically. Discussion Aneurysms of the AICA-PICA variant are rare. The radiological features and surgical management represent a unique clinical entity and are discussed below. Conclusion The prevalence of the AICA-PICA variant might be high but aneurysms in this vessel are rare. The scant knowledge available on this subject makes it a diagnostic difficulty. PMID:27017276

  17. Abnormalities in personal space and parietal-frontal function in schizophrenia.

    PubMed

    Holt, Daphne J; Boeke, Emily A; Coombs, Garth; DeCross, Stephanie N; Cassidy, Brittany S; Stufflebeam, Steven; Rauch, Scott L; Tootell, Roger B H

    2015-01-01

    Schizophrenia is associated with subtle abnormalities in day-to-day social behaviors, including a tendency in some patients to "keep their distance" from others in physical space. The neural basis of this abnormality, and related changes in social functioning, is unknown. Here we examined, in schizophrenic patients and healthy control subjects, the functioning of a parietal-frontal network involved in monitoring the space immediately surrounding the body ("personal space"). Using fMRI, we found that one region of this network, the dorsal intraparietal sulcus (DIPS), was hyper-responsive in schizophrenic patients to face stimuli appearing to move towards the subjects, intruding into personal space. This hyper-responsivity was predicted both by the size of personal space (which was abnormally elevated in the schizophrenia group) and the severity of negative symptoms. In contrast, in a second study, the activity of two lower-level visual areas that send information to DIPS (the fusiform face area and middle temporal area) was normal in schizophrenia. Together, these findings suggest that changes in parietal-frontal networks that support the sensory-guided initiation of behavior, including actions occurring in the space surrounding the body, contribute to social dysfunction and negative symptoms in schizophrenia.

  18. Parietal disruption alters audiovisual binding in the sound-induced flash illusion.

    PubMed

    Kamke, Marc R; Vieth, Harrison E; Cottrell, David; Mattingley, Jason B

    2012-09-01

    Selective attention and multisensory integration are fundamental to perception, but little is known about whether, or under what circumstances, these processes interact to shape conscious awareness. Here, we used transcranial magnetic stimulation (TMS) to investigate the causal role of attention-related brain networks in multisensory integration between visual and auditory stimuli in the sound-induced flash illusion. The flash illusion is a widely studied multisensory phenomenon in which a single flash of light is falsely perceived as multiple flashes in the presence of irrelevant sounds. We investigated the hypothesis that extrastriate regions involved in selective attention, specifically within the right parietal cortex, exert an influence on the multisensory integrative processes that cause the flash illusion. We found that disruption of the right angular gyrus, but not of the adjacent supramarginal gyrus or of a sensory control site, enhanced participants' veridical perception of the multisensory events, thereby reducing their susceptibility to the illusion. Our findings suggest that the same parietal networks that normally act to enhance perception of attended events also play a role in the binding of auditory and visual stimuli in the sound-induced flash illusion.

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

    PubMed

    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.

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

    PubMed

    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.

  1. The cellular component in the parietal infiltrate of inflammatory abdominal aortic aneurysms (IAAA).

    PubMed

    Stella, A; Gargiulo, M; Pasquinelli, G; Preda, P; Faggioli, G L; Cenacchi, G; D'Addato, M

    1991-02-01

    Eight cases of inflammatory abdominal aortic aneurysm (IAAA) (group I) and a control group of ten cases of atherosclerotic abdominal aortic aneurysm (AAA) with little or no parietal inflammatory infiltrate (group II) were studied; using light microscopy, transmission electron microscopy (TEM), and immunohistochemistry. These were used to define cell composition in the inflammatory process, the degree of cell activation and alteration of connective tissue. Large numbers of B lymphocytes were present in IAAA with preservation of the T4/T8 ratio. In addition, HLA-DR and the IL2-R antigen (specific for activated cells) were widely expressed in the cell population. The interstitial matrix contained deposits of IgG, IgM and C3c together with an increase in type III collagen and a reduction in elastin which appeared fragmented and swollen. This study, therefore, characterised the cellular component of the parietal inflammatory infiltrate in IAAA. The degree of activation shown by these cell elements and the activation of complement suggest that the relevant antigen may have been localised in the aneurysm wall at the time of observation.

  2. Parietal Fast Sleep Spindle Density Decrease in Alzheimer's Disease and Amnesic Mild Cognitive Impairment

    PubMed Central

    Gorgoni, Maurizio; Lauri, Giulia; Truglia, Ilaria; Cordone, Susanna; Sarasso, Simone; Scarpelli, Serena; Mangiaruga, Anastasia; D'Atri, Aurora; Tempesta, Daniela; Ferrara, Michele; Marra, Camillo; Rossini, Paolo Maria; De Gennaro, Luigi

    2016-01-01

    Several studies have identified two types of sleep spindles: fast (13–15 Hz) centroparietal and slow (11–13 Hz) frontal spindles. Alterations in spindle activity have been observed in Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). Only few studies have separately assessed fast and slow spindles in these patients showing a reduction of fast spindle count, but the possible local specificity of this phenomenon and its relation to cognitive decline severity are not clear. Moreover, fast and slow spindle density have never been assessed in AD/MCI. We have assessed fast and slow spindles in 15 AD patients, 15 amnesic MCI patients, and 15 healthy elderly controls (HC). Participants underwent baseline polysomnographic recording (19 cortical derivations). Spindles during nonrapid eye movements sleep were automatically detected, and spindle densities of the three groups were compared in the derivations where fast and slow spindles exhibited their maximum expression (parietal and frontal, resp.). AD and MCI patients showed a significant parietal fast spindle density decrease, positively correlated with Minimental State Examination scores. Our results suggest that AD-related changes in spindle density are specific for frequency and location, are related to cognitive decline severity, and may have an early onset in the pathology development. PMID:27066274

  3. Spatial effects of shifting prisms on properties of posterior parietal cortex neurons.

    PubMed

    Karkhanis, Anushree N; Heider, Barbara; Silva, Fabian Muñoz; Siegel, Ralph M

    2014-08-15

    The posterior parietal cortex contains neurons that respond to visual stimulation and motor behaviour. The objective of the current study was to test short-term adaptation in neurons in macaque area 7a and the dorsal prelunate during visually guided reaching using Fresnel prisms that displaced the visual field. The visual perturbation shifted the eye position and created a mismatch between perceived and actual reach location. Two non-human primates were trained to reach to visual targets before, during and after prism exposure while fixating the reach target in different locations. They were required to reach to the physical location of the reach target and not the perceived, displaced location. While behavioural adaptation to the prisms occurred within a few trials, the majority of neurons responded to the distortion either with substantial changes in spatial eye position tuning or changes in overall firing rate. These changes persisted even after prism removal. The spatial changes were not correlated with the direction of induced prism shift. The transformation of gain fields between conditions was estimated by calculating the translation and rotation in Euler angles. Rotations and translations of the horizontal and vertical spatial components occurred in a systematic manner for the population of neurons suggesting that the posterior parietal cortex retains a constant representation of the visual field remapping between experimental conditions.

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

    PubMed Central

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

    2015-01-01

    Summary 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. PMID:26257053

  5. A micromethod for the assay of cellular secretory physiology: Application to rabbit parietal cells

    SciTech Connect

    Adrian, T.E.; Goldenring, J.R.; Oddsdottir, M.; Zdon, M.J.; Zucker, K.A.; Lewis, J.J.; Modlin, I.M. )

    1989-11-01

    A micromethod for investigating secretory physiology in isolated cells was evaluated. The method utilized a specially designed polycarbonate incubation chamber to provide constant oxygenation to cells incubating in a 96-well microtiter plate. Cells were rapidly separated from media by vacuum filtration. Isolated parietal cells were utilized to demonstrate the versatility of the method for assay of intracellular accumulation of ({sup 14}C)-aminopyrine, secretion of intrinsic factor into the medium, and assay of intracellular cAMP. Histamine stimulated the uptake of ({sup 14}C)aminopyrine and intrinsic factor secretion in a sustained and linear fashion. At the end of the 2-h period uptake of aminopyrine and secretion of intrinsic factor were increased 17- and 5-fold, respectively. This response to histamine was accompanied by a rapid and sustained 3-fold rise in intracellular cyclic AMP. In contrast, carbamylcholine caused a transient increase in ({sup 14}C)aminopyrine accumulation and intrinsic factor secretion which was most pronounced during the first 10 min and had almost ceased by 30 min. Carbamylcholine had no effect on intracellular cAMP levels. This new method, which can handle 400 replicates using parietal cells from the fundic mucosa of a single rabbit, is suitable for studying the time course of intracellular events which accompany general secretory processes.

  6. Gastric hyperplasia and parietal cell loss in Taenia taeniaeformis inoculated immunodeficient mice.

    PubMed

    Lagapa, Jose Trinipil; Konno, Kenjiro; Oku, Yuzaburo; Nonaka, Nariaki; Ito, Mamoru; Kamiya, Masao

    2002-03-01

    Immunodeficient mice were studied to determine their suitability as models in investigating the role of Taenia taeniaeformis larval products in the development of gastric hyperplasia. Recombinant active gene 2 (RAG2)-deficient and severe combined immune-deficient (SCID) mice were studied as candidate animal models. RAG2-deficient mice inoculated orally with T. taeniaeformis eggs developed gastric hyperplasia with alcian blue-periodic acid-Schiff-positive cell proliferation similar to those of rats. SCID mice inoculated with different doses and routes of T. taeniaeformis in vitro-hatched oncospheres and those orally inoculated with eggs resulted also in different degrees of gastric hyperplasia. Influence of inoculation forms of parasite, doses and routes of inoculation on initiation of hyperplastic gastropathy was suggested to be dependent on number and size of developed larvae. Both RAG2-deficient and SCID mice with hyperplastic mucosa were observed with significant loss of parietal cells. Apparent decrease in parietal cell number was observed in SCID mice at 2 weeks after intraperitoneal inoculation with oncospheres before hyperplastic lesions developed. Earliest occurrence of gastric hyperplasia in SCID mice was observed at 3 weeks after oral inoculation of in vitro-hatched oncospheres, sooner than orally inoculated rats. The results suggested that these immunodeficient mice could be used as animal models to study factors involved in T. taeniaeformis-induced gastric mucous cell hyperplasia.

  7. Alpha power increases in right parietal cortex reflects focused internal attention.

    PubMed

    Benedek, Mathias; Schickel, Rainer J; Jauk, Emanuel; Fink, Andreas; Neubauer, Aljoscha C

    2014-04-01

    This study investigated the functional significance of EEG alpha power increases, a finding that is consistently observed in various memory tasks and specifically during divergent thinking. It was previously shown that alpha power is increased when tasks are performed in mind-e.g., when bottom-up processing is prevented. This study aimed to examine the effect of task-immanent differences in bottom-up processing demands by comparing two divergent thinking tasks, one intrinsically relying on bottom-up processing (sensory-intake task) and one that is not (sensory-independence task). In both tasks, stimuli were masked in half of the trials to establish conditions of higher and lower internal processing demands. In line with the hypotheses, internal processing affected performance and led to increases in alpha power only in the sensory-intake task, whereas the sensory-independence task showed high levels of task-related alpha power in both conditions. Interestingly, conditions involving focused internal attention showed a clear lateralization with higher alpha power in parietal regions of the right hemisphere. Considering evidence from fMRI studies, right-parietal alpha power increases may correspond to a deactivation of the right temporoparietal junction, reflecting an inhibition of the ventral attention network. Inhibition of this region is thought to prevent reorienting to irrelevant stimulation during goal-driven, top-down behavior, which may serve the executive function of task shielding during demanding cognitive tasks such as idea generation and mental imagery.

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

    PubMed

    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.

  9. Posterior parietal cortex as part of a neural network for directed attention in rats.

    PubMed

    Reep, Roger L; Corwin, James V

    2009-02-01

    A rodent model of directed attention has been developed based upon behavioral analysis of contralateral neglect, pharmacological manipulations, and anatomical analysis of neural circuitry. In each of these three domains the rodent model exhibits striking similarities to humans. We hypothesize that there is a specific thalamo-cortical-basal ganglia network that subserves spatial attentional functions. Key components of this network are medial agranular and posterior parietal cortex, dorsocentral striatum, and the lateral posterior thalamic nucleus. Several issues need to be addressed before we can hope to realistically understand or model the functions of this network. Among these are the roles of medial versus lateral posterior parietal cortex; cholinergic mechanisms in attention; interhemispheric interactions; the role of synchronous firing at the cortical, striatal, and thalamic levels; interactions between cortical and thalamic projections to the striatum; interactions between cortical and nigral inputs to the thalamus; the role of collicular inputs to the lateral posterior thalamic nucleus; the role of cerebral cortex versus superior colliculus in driving the motor output expressed as orienting behavior during directed attention; the extent to which the circuitry we describe for directed attention also plays a role in other forms of attention.

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

    PubMed

    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.

  11. Alpha stimulation of the human parietal cortex attunes tactile perception to external space.

    PubMed

    Ruzzoli, Manuela; Soto-Faraco, Salvador

    2014-02-03

    An intriguing question in neuroscience concerns how somatosensory events on the skin are represented in the human brain. Since Head and Holmes' [1] neuropsychological dissociation between localizing touch on the skin and localizing body parts in external space, touch is considered to operate in a variety of spatial reference frames [2]. At least two representations of space are in competition during orienting to touch: a somatotopic one, reflecting the organization of the somatosensory cortex (S1) [3], and a more abstract, external reference frame that factors postural changes in relation to body parts and/or external space [4, 5]. Previous transcranial magnetic stimulation (TMS) studies suggest that the posterior parietal cortex (PPC) plays a key role in supporting representations as well as orienting attention in an external reference frame [4, 6]. Here, we capitalized on the TMS entrainment approach [7, 8], targeting the intraparietal sulcus (IPS). We found that frequency-specific (10 Hz) tuning of the PPC induced spatially specific enhancement of tactile detection that was expressed in an external reference frame. This finding establishes a tight causal link between a concrete form of brain activity (10 Hz oscillation) and a specific type of spatial representation, revealing a fundamental property of how the parietal cortex encodes information.

  12. Noradrenaline transporter blockade increases fronto-parietal functional connectivity relevant for working memory.

    PubMed

    Hernaus, Dennis; Casales Santa, Marta Ma; Offermann, Jan Stefan; Van Amelsvoort, Thérèse

    2017-03-10

    Experimental animal work has demonstrated that dopamine and noradrenaline play an essential role in modulating prefrontal cortex-mediated networks underlying working memory performance. Studies of functional connectivity have been instrumental in extending such notions to humans but, so far, have almost exclusively focussed on pharmacological agents with a predominant dopaminergic mechanism of action. Here, we investigate the effect of a single dose of atomoxetine 60mg, a noradrenaline transporter inhibitor, on working memory performance and associated functional connectivity during an n-back task in 19 healthy male volunteers. Atomoxetine increased functional connectivity between right anterior insula and dorsolateral prefrontal cortex, precentral gyrus, posterior parietal cortex and precuneus during the high-working memory load condition of the n-back task. Increased atomoxetine-induced insula-dorsolateral prefrontal cortex functional connectivity during this condition correlated with decreased reaction time variability and was furthermore predicted by working memory capacity. These results show for the first time that noradrenaline transporter blockade-induced increases in cortical catecholamines accentuate fronto-parietal working memory-related network integrity. The observation of significant inter-subject variability in response to atomoxetine has implications for inverted-U frameworks of dopamine and noradrenaline function, which could be useful to predict drug effects in clinical disorders with variable treatment response.

  13. Biofidelic neck influences head kinematics of parietal and occipital impacts following short falls in infants.

    PubMed

    Sullivan, Sarah; Coats, Brittany; Margulies, Susan S

    2015-09-01

    Falls are a major cause of traumatic head injury in children. Understanding head kinematics during low height falls is essential for evaluating injury risk and designing mitigating strategies. Typically, these measurements are made with commercial anthropomorphic infant surrogates, but these surrogates are designed based on adult biomechanical data. In this study, we improve upon the state-of-the-art anthropomorphic testing devices by incorporating new infant cadaver neck bending and tensile data. We then measure head kinematics following head-first falls onto 4 impact surfaces from 3 fall heights with occipital and parietal head impact locations. The biofidelic skull compliance and neck properties of the improved infant surrogate significantly influenced the measured kinematic loads, decreasing the measured impact force and peak angular accelerations, lowering the expected injury risk. Occipital and parietal impacts exhibited distinct kinematic responses in primary head rotation direction and the magnitude of the rotational velocities and accelerations, with larger angular velocities as the head rebounded after occipital impacts. Further evaluations of injury risk due to short falls should take into account the impact surface and head impact location, in addition to the fall height.

  14. The Effect of Thoracoscopic Pleurodesis in Primary Spontaneous Pneumothorax: Apical Parietal Pleurectomy versus Pleural Abrasion

    PubMed Central

    Huh, Up; Cho, Jeong Su; I, Hoseok; Lee, Jon Geun; Lee, Jun Ho

    2012-01-01

    Background The standard operative treatment of primary spontaneous pneumothorax (PSP) is thoracoscopic wedge resection, but necessity of pleurodesis still remains controversial. Nevertheless, pleural procedure after wedge resection such as pleurodesis has been performed in some patients who need an extremely low recurrence rate. Materials and Methods From January 2000 to July 2010, 207 patients who had undergone thoracoscopic wedge resection and pleurodesis were enrolled in this study. All patients were divided into two groups according to the methods of pleurodesis; apical parietal pleurectomy (group A) and pleural abrasion (group B). The recurrence after surgery had been checked by reviewing medical record through follow-up in ambulatory care clinic or calling to the patients, directly until January 2011. Results Of the 207 patients, the recurrence rate of group A and B was 9.1% and 12.8%, respectively and there was a significant difference (p=0.01, Cox's proportional hazard model). There was no significant difference in age, gender, smoking status, and body mass index between two groups. Conclusion This study suggests that the risk of recurrence after surgery in PSP is significantly low in patients who underwent thoracoscopic wedge resection with parietal pleurectomy than pleural abrasion. PMID:23130305

  15. Contextual modulation of pain in masochists: involvement of the parietal operculum and insula.

    PubMed

    Kamping, Sandra; Andoh, Jamila; Bomba, Isabelle C; Diers, Martin; Diesch, Eugen; Flor, Herta

    2016-02-01

    Pain can be modulated by contextual stimuli, such as emotions, social factors, or specific bodily perceptions. We presented painful laser stimuli together with body-related masochistic visual stimuli to persons with and without preferred masochistic sexual behavior and used neutral, positive, and negative pictures with and without painful stimuli as control. Masochists reported substantially reduced pain intensity and unpleasantness in the masochistic context compared with controls but had unaltered pain perception in the other conditions. Functional magnetic resonance imaging revealed that masochists activated brain areas involved in sensory-discriminative processing rather than affective pain processing when they received painful stimuli on a masochistic background. The masochists compared with the controls displayed attenuated functional connectivity of the parietal operculum with the left and right insulae, the central operculum, and the supramarginal gyrus. Masochists additionally showed negative correlations between the duration of interest in masochistic activities and activation of areas involved in motor activity and affective processing. We propose that the parietal operculum serves as an important relay station that attenuates the affective-motivational aspects of pain in masochists. This novel mechanism of pain modulation might be related to multisensory integration and has important implications for the assessment and treatment of pain.

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

    PubMed

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

    PubMed

    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.

  18. Alpha power increases in right parietal cortex reflects focused internal attention

    PubMed Central

    Benedek, Mathias; Schickel, Rainer J.; Jauk, Emanuel; Fink, Andreas; Neubauer, Aljoscha C.

    2014-01-01

    This study investigated the functional significance of EEG alpha power increases, a finding that is consistently observed in various memory tasks and specifically during divergent thinking. It was previously shown that alpha power is increased when tasks are performed in mind—e.g., when bottom-up processing is prevented. This study aimed to examine the effect of task-immanent differences in bottom-up processing demands by comparing two divergent thinking tasks, one intrinsically relying on bottom-up processing (sensory-intake task) and one that is not (sensory-independence task). In both tasks, stimuli were masked in half of the trials to establish conditions of higher and lower internal processing demands. In line with the hypotheses, internal processing affected performance and led to increases in alpha power only in the sensory-intake task, whereas the sensory-independence task showed high levels of task-related alpha power in both conditions. Interestingly, conditions involving focused internal attention showed a clear lateralization with higher alpha power in parietal regions of the right hemisphere. Considering evidence from fMRI studies, right-parietal alpha power increases may correspond to a deactivation of the right temporoparietal junction, reflecting an inhibition of the ventral attention network. Inhibition of this region is thought to prevent reorienting to irrelevant stimulation during goal-driven, top-down behavior, which may serve the executive function of task shielding during demanding cognitive tasks such as idea generation and mental imagery. PMID:24561034

  19. Contextual modulation of pain in masochists: involvement of the parietal operculum and insula

    PubMed Central

    Kamping, Sandra; Andoh, Jamila; Bomba, Isabelle C.; Diers, Martin; Diesch, Eugen; Flor, Herta

    2015-01-01

    Abstract Pain can be modulated by contextual stimuli, such as emotions, social factors, or specific bodily perceptions. We presented painful laser stimuli together with body-related masochistic visual stimuli to persons with and without preferred masochistic sexual behavior and used neutral, positive, and negative pictures with and without painful stimuli as control. Masochists reported substantially reduced pain intensity and unpleasantness in the masochistic context compared with controls but had unaltered pain perception in the other conditions. Functional magnetic resonance imaging revealed that masochists activated brain areas involved in sensory-discriminative processing rather than affective pain processing when they received painful stimuli on a masochistic background. The masochists compared with the controls displayed attenuated functional connectivity of the parietal operculum with the left and right insulae, the central operculum, and the supramarginal gyrus. Masochists additionally showed negative correlations between the duration of interest in masochistic activities and activation of areas involved in motor activity and affective processing. We propose that the parietal operculum serves as an important relay station that attenuates the affective-motivational aspects of pain in masochists. This novel mechanism of pain modulation might be related to multisensory integration and has important implications for the assessment and treatment of pain. PMID:26808014

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

    PubMed

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

    2017-02-14

    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.

  1. Prism adaptation reverses the local processing bias in patients with right temporo-parietal junction lesions

    PubMed Central

    Rafal, Robert D.; List, Alexandra

    2009-01-01

    Lesions to the right temporo-parietal cortex commonly result in hemispatial neglect. Lesions to the same area are also associated with hyperattention to local details of a scene and difficulty perceiving the global structure. This local processing bias is an important factor contributing to neglect and may contribute to the higher prevalence of the disorder following right compared with left hemisphere strokes. In recent years, visuomotor adaptation to rightward-shifting prisms has been introduced as a promising treatment for hemispatial neglect. Explanations for these improvements have generally described a leftward realignment of attention, however, the present investigation provides evidence that prism adaptation reduces the local processing bias. Five patients with right temporal-parietal junction lesions were asked to identify the global or local levels of hierarchical figures before and after visuomotor adaptation to rightward-shifting prisms. Prior to prism adaptation the patients had difficulty ignoring the local elements when identifying the global component. Following prism adaptation, however, this pattern was reversed, with greater global interference during local level identification. The results suggest that prism adaptation may improve non-spatially lateralized deficits that contribute to the neglect syndrome. PMID:19416951

  2. Object integration requires attention: Visual search for Kanizsa figures in parietal extinction.

    PubMed

    Gögler, Nadine; Finke, Kathrin; Keller, Ingo; Müller, Hermann J; Conci, Markus

    2016-11-01

    The contribution of selective attention to object integration is a topic of debate: integration of parts into coherent wholes, such as in Kanizsa figures, is thought to arise either from pre-attentive, automatic coding processes or from higher-order processes involving selective attention. Previous studies have attempted to examine the role of selective attention in object integration either by employing visual search paradigms or by studying patients with unilateral deficits in selective attention. Here, we combined these two approaches to investigate object integration in visual search in a group of five patients with left-sided parietal extinction. Our search paradigm was designed to assess the effect of left- and right-grouped nontargets on detecting a Kanizsa target square. The results revealed comparable reaction time (RT) performance in patients and controls when they were presented with displays consisting of a single to-be-grouped item that had to be classified as target vs. nontarget. However, when display size increased to two items, patients showed an extinction-specific pattern of enhanced RT costs for nontargets that induced a partial shape grouping on the right, i.e., in the attended hemifield (relative to the ungrouped baseline). Together, these findings demonstrate a competitive advantage for right-grouped objects, which in turn indicates that in parietal extinction, attentional competition between objects particularly limits integration processes in the contralesional, i.e., left hemifield. These findings imply a crucial contribution of selective attentional resources to visual object integration.

  3. Isolating response inhibition in the brain: Parietal versus frontal contribution.

    PubMed

    Kolodny, Tamar; Mevorach, Carmel; Shalev, Lilach

    2017-03-01

    Response inhibition is a main function of cognitive control and its neural substrates have been studied extensively. However, it is still a question whether previous brain imaging investigations were successful in isolating specific response inhibition activation. In the current study we attempted to pinpoint response inhibition in the brain using a Go/No-go task and fMRI, by contrasting rare-No-go trials with prevalent-No-go trials. Although inhibition is required in all No-go trials, task variants with rare-No-go cases (25%) create a prepotent response which elicits a strong demand for inhibition, while task variants with prevalent-No-go cases (75%) require very little inhibition effort. Since the neural activation in this design is extracted solely from No-go trials, differing only in the extent of inhibitory demand, the analysis avoids contamination of the data with motor effects or visual factors. Using this experimental design we highlight the contribution of the parietal cortex (bilaterally) to inhibitory processes, while casting doubts about the specificity of frontal activation in such processes. Future studies are required to verify that bilateral intraparietal sulcus and left temporo-parietal junction activations could be markers of inhibitory control.

  4. Frontal and occipital-parietal alpha oscillations distinguish between stimulus conflict and response conflict

    PubMed Central

    Tang, Dandan; Hu, Li; Lei, Yi; Li, Hong; Chen, Antao

    2015-01-01

    Conflicts between target and distraction can occur at the level of both stimulus and response processing. However, the neural oscillations underlying occurrence of the interference in different levels have not been understood well. Here, we reveal such a neural oscillation modulation by combining a 4:2 mapping design (two targets are mapped into one response key) with a practice paradigm (pretest, practice, and posttest) when healthy human participants were performing a novel color-word flanker task. Response time (RT) results revealed constant stimulus conflict (SC, stimulus incongruent minus congruent, SI-CO) but increased response conflict (RC, response incongruent minus stimulus incongruent, RI-SI) with practice. Event-related potential (ERP) results demonstrated stable P3 amplitude differences for the SI-CO in the centro-parietal region across practice, which may reflect maintenance of the stimulus processing; and significantly larger P3 amplitudes in the same region for the RI relative to SI trial type in posttest, which may reflect inhibition of the distraction response. Further, neural oscillatory results showed that with practice, the lower alpha band in the frontal region and the upper alpha band in the occipital-parietal region distinguished between stimulus- and response-conflicts, respectively, suggesting that practice reduces the alertness (sensitiveness) of the brain to conflict occurrence, and enhances stimulus-response associations. PMID:26300758

  5. Visual feature integration indicated by pHase-locked frontal-parietal EEG signals.

    PubMed

    Phillips, Steven; Takeda, Yuji; Singh, Archana

    2012-01-01

    The capacity to integrate multiple sources of information is a prerequisite for complex cognitive ability, such as finding a target uniquely identifiable by the conjunction of two or more features. Recent studies identified greater frontal-parietal synchrony during conjunctive than non-conjunctive (feature) search. Whether this difference also reflects greater information integration, rather than just differences in cognitive strategy (e.g., top-down versus bottom-up control of attention), or task difficulty is uncertain. Here, we examine the first possibility by parametrically varying the number of integrated sources from one to three and measuring phase-locking values (PLV) of frontal-parietal EEG electrode signals, as indicators of synchrony. Linear regressions, under hierarchical false-discovery rate control, indicated significant positive slopes for number of sources on PLV in the 30-38 Hz, 175-250 ms post-stimulus frequency-time band for pairs in the sagittal plane (i.e., F3-P3, Fz-Pz, F4-P4), after equating conditions for behavioural performance (to exclude effects due to task difficulty). No such effects were observed for pairs in the transverse plane (i.e., F3-F4, C3-C4, P3-P4). These results provide support for the idea that anterior-posterior phase-locking in the lower gamma-band mediates integration of visual information. They also provide a potential window into cognitive development, seen as developing the capacity to integrate more sources of information.

  6. Optical imaging in galagos reveals parietal-frontal circuits underlying motor behavior.

    PubMed

    Stepniewska, Iwona; Friedman, Robert M; Gharbawie, Omar A; Cerkevich, Christina M; Roe, Anna W; Kaas, Jon H

    2011-09-13

    The posterior parietal cortex (PPC) of monkeys and prosimian galagos contains a number of subregions where complex, behaviorally meaningful movements, such as reaching, grasping, and body defense, can be evoked by electrical stimulation with long trains of electrical pulses through microelectrodes. Shorter trains of pulses evoke no or simple movements. One possibility for the difference in effectiveness of intracortical microstimulation is that long trains activate much larger regions of the brain. Here, we show that long-train stimulation of PPC does not activate widespread regions of frontal motor and premotor cortex but instead, produces focal, somatotopically appropriate activations of frontal motor and premotor cortex. Shorter stimulation trains activate the same frontal foci but less strongly, showing that longer stimulus trains do not produce less specification. Because the activated sites in frontal cortex correspond to the locations of direct parietal-frontal anatomical connections from the stimulated PPC subregions, the results show the usefulness of optical imaging in conjunction with electrical stimulation in showing functional pathways between nodes in behavior-specific cortical networks. Thus, long-train stimulation is effective in evoking ethologically relevant sequences of movements by activating nodes in a cortical network for a behaviorally relevant period rather than spreading activation in a nonspecific manner.

  7. Parietal Bone Thickness and Vascular Diameters in Adult Modern Humans: A Survey on Cranial Remains.

    PubMed

    Eisová, Stanislava; Rangel de Lázaro, Gizéh; Píšová, Hana; Pereira-Pedro, Sofia; Bruner, Emiliano

    2016-07-01

    Cranial bone thickness varies among modern humans, and many factors influencing this variability remain unclear. Growth hormones and physical activity are thought to influence the vault thickness. Considering that both systemic factors and energy supply influence the vascular system, and taking into account the structural and biomechanical interaction between endocranial vessels and vault bones, in this study we evaluate the correlation between vascular and bone diameters. In particular, we tested the relationship between the thickness of the parietal bone (which is characterized, in modern humans, by a complex vascular network) and the lumen size of the middle meningeal and diploic vessels, in adult modern humans. Our results show no patent correlation between the thickness of parietal bone and the size of the main vascular channels. Values and distributions of the branching patterns, as well as anatomical relationships between vessels and bones, are also described in order to provide information concerning the arrangement of the endocranial vascular morphology. This information is relevant in both evolutionary and medical contexts. Anat Rec, 299:888-896, 2016. © 2016 Wiley Periodicals, Inc.

  8. True Memory, False Memory, and Subjective Recollection Deficits after Focal Parietal Lobe Lesions

    PubMed Central

    Drowos, David B.; Berryhill, Marian; André, Jessica M.; Olson, Ingrid R.

    2010-01-01

    Objective There is mounting evidence that the posterior parietal cortex (PPC) plays an important role in episodic memory. We previously found that patients with PPC damage exhibit retrieval-related episodic memory deficits. Our objective was to assess whether parietal lobe damage affects episodic memory on a different task: the Deese-Roediger-McDermott (DRM) false-memory paradigm. Method Two patients with bilateral PPC damage and matched controls were tested. In Experiment 1, the task was to remember words; in Experiment 2 the task was to remember pictures of common objects. Prior studies have shown that normal participants have high levels of false memory to words, low levels to pictures. Results The patients exhibited significantly lower levels of false memory to words. The patients' false memories were accompanied by reduced levels of recollection, as tested by a Remember/Know procedure. It is unlikely that a failure of gist processing accounts for these results, as patients accurately remembered thematic elements of short vignettes, but failed to remember details. These results support the view that portions of the PPC play a critical role in objective and subjective aspects of recollection. PMID:20604621

  9. Biofidelic neck influences head kinematics of parietal and occipital impacts following short falls in infants

    PubMed Central

    Sullivan, Sarah; Coats, Brittany; Margulies, Susan S.

    2015-01-01

    Falls are a major cause of traumatic head injury in children. Understanding head kinematics during low height falls is essential for evaluating injury risk and designing mitigating strategies. Typically, these measurements are made with commercial anthropomorphic infant surrogates, but these surrogates are designed based on adult biomechanical data. In this study, we improve upon the state-of-the-art anthropomorphic testing devices by incorporating new infant cadaver neck bending and tensile data. We then measure head kinematics following head-first falls onto 4 impact surfaces from 3 fall heights with occipital and parietal head impact locations. The biofidelic skull compliance and neck properties of the improved infant surrogate significantly influenced the measured kinematic loads, decreasing the measured impact force and peak angular accelerations, lowering the expected injury risk. Occipital and parietal impacts exhibited distinct kinematic responses in primary head rotation direction and the magnitude of the rotational velocities and accelerations, with larger angular velocities as the head rebounded after occipital impacts. Further evaluations of injury risk due to short falls should take into account the impact surface and head impact location, in addition to the fall height. PMID:26072183

  10. Anatomical segregation of representations of personally familiar and famous people in the temporal and parietal cortices.

    PubMed

    Sugiura, Motoaki; Sassa, Yuko; Watanabe, Jobu; Akitsuki, Yuko; Maeda, Yasuhiro; Matsue, Yoshihiko; Kawashima, Ryuta

    2009-10-01

    Person recognition has been assumed to entail many types of person-specific cognitive responses, including retrieval of knowledge, episodic recollection, and emotional responses. To demonstrate the cortical correlates of this modular structure of multimodal person representation, we investigated neural responses preferential to personally familiar people and responses dependent on familiarity with famous people in the temporal and parietal cortices. During functional magnetic resonance imaging (fMRI) measurements, normal subjects recognized personally familiar names (personal) or famous names with high or low degrees of familiarity (high or low, respectively). Effects of familiarity with famous people (i.e., high-low) were identified in the bilateral angular gyri, the left supramarginal gyrus, the middle part of the bilateral posterior cingulate cortices, and the left precuneus. Activation preferentially relevant to personally familiar people (i.e., personal-high) was identified in the bilateral temporo-parietal junctions, the right anterolateral temporal cortices, posterior middle temporal gyrus, posterior cingulate cortex (with a peak in the posterodorsal part), and the left precuneus; these activation foci exhibited varying degrees of activation for high and low names. An equivalent extent of activation was observed for all familiar names in the bilateral temporal poles, the left orbito-insular junction, the middle temporal gyrus, and the anterior part of the posterior cingulate cortex. The results demonstrated that distinct cortical areas supported different types of cognitive responses, induced to different degrees during recognition of famous and personally familiar people, providing neuroscientific evidence for the modularity of multimodal person representation.

  11. Lateral posterior parietal activity during reality monitoring discriminations of memories of high and low perceptual vividness.

    PubMed

    King, Danielle R; Schubert, Misty L; Miller, Michael B

    2015-09-01

    Regions of the lateral posterior parietal cortex (PPC) tend to be more active during recognition of previously studied items compared to correct rejection of unstudied items. Previously, we demonstrated that this effect is source-specific. While items that were encoded through visual perception elicited robust successful retrieval activity in the lateral PPC during a subsequent source memory test, items that were visually imagined did not elicit this effect. Memories of perceived events typically contain more perceptually-based contextual details than memories of imagined events. Therefore, source-based differences in lateral parietal activity might be due to a difference in the perceptual vividness of memories of perceived and imagined events. The goal of the present study was to test this hypothesis. Participants perceived and imagined items in both high and low perceptual vividness conditions. Experiment 1 demonstrated that memories for items encoded in the high vividness conditions contained significantly greater visual detail than memories encoded in the low vividness conditions. In Experiment 2, participants were scanned while they made source memory judgments about items that were previously perceived and imagined in high and low vividness conditions. Consistent with previous findings, the left lateral PPC was more active during retrieval of perceived compared to imagined events. However, lateral PPC activity did not vary according to vividness, suggesting that source effects in this region cannot be explained by a difference in the perceptual vividness of memories encoded through perception versus imagination.

  12. Neural circuitry involved in quitting after repeated failures: role of the cingulate and temporal parietal junction

    PubMed Central

    Zhao, Weihua; Kendrick, Keith M; Chen, Fei; Li, Hong; Feng, Tingyong

    2016-01-01

    The more times people fail the more likely they are to give up, however little is known about the neural mechanisms underlying this impact of repeated failure on decision making. Here we have used a visual shape discrimination task with computer-controlled feedback combined with functional magnetic resonance imaging (fMRI) to investigate the neural circuits involved. The behavioral task confirmed that the more times subjects experienced failure the more likely they were to give up, with three successive failures being the key threshold and the majority of subjects reaching the point where they decided to quit and try a new stimulus set after three or four failures. The fMRI analysis revealed activity changes in frontal, parietal, temporal, limbic and striatal regions, especially anterior cingulate cortex (ACC), posterior cingulate cortex (PCC) and temporal parietal junction (TPJ) associated with the number of previous failures experienced. Furthermore, their parameter estimates were predictive of subjects’ quitting rate. Thus, subjects reach the point where they decide to quit after three/four failures and this is associated with differential changes in brain regions involved in error monitoring and reward which regulate both failure detection and changes in decision-making strategy. PMID:27097529

  13. FoxP2 expression in the cerebellum and inferior olive: development of the transverse stripe-shaped expression pattern in the mouse cerebellar cortex.

    PubMed

    Fujita, Hirofumi; Sugihara, Izumi

    2012-02-15

    Many molecules are expressed heterogeneously in subpopulations of cerebellar Purkinje cells (PCs) and inferior olive (IO) neurons during development or in adulthood. These expression patterns are often organized in longitudinal stripes in the cerebellar cortex, which may be related to functional compartmentalization. FoxP2, a transcription factor, is expressed in PCs and IO neurons, but the details of its expression pattern remain unclear. Here we examined FoxP2 expression patterns systematically by immunostaining serial sections of the hindbrain from embryonic day 14.5 to adulthood in mice. FoxP2 was highly expressed in virtually all PCs at and before postnatal day 6 (P6), except for those in the flocculus and small parts of the nodulus (vermal lobule X), where FoxP2 expression was moderate or absent. After P6, FoxP2 expression gradually diminished in PCs in some areas. In adults, FoxP2 was expressed, less intensely than in earlier stages, in subsets of PCs that were mostly arranged transversely along the folial apices. In contrast, FoxP2 was expressed intensely in most IO neurons during development and in adulthood. FoxP2 was also expressed in a small population of neurons in the cerebellar nuclei. FoxP2 expression in adult rats and chicks was generally comparable to that in adult mice, suggesting evolutionary conservation of the expression pattern. Thus, the FoxP2 expression pattern reflects new transverse compartmentalization in the adult cerebellar cortex, although its functional significance remains unclear.

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

    PubMed

    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.

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

    PubMed Central

    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

  16. Polarized Distribution of IQGAP Proteins in Gastric Parietal Cells and Their Roles in Regulated Epithelial Cell Secretion

    PubMed Central

    Zhou, Rihong; Guo, Zhen; Watson, Charles; Chen, Emily; Kong, Rong; Wang, Wenxian; Yao, Xuebiao

    2003-01-01

    Actin cytoskeleton plays an important role in the establishment of epithelial cell polarity. Cdc42, a member of Rho GTPase family, modulates actin dynamics via its regulators, such as IQGAP proteins. Gastric parietal cells are polarized epithelial cells in which regulated acid secretion occurs in the apical membrane upon stimulation. We have previously shown that actin isoforms are polarized to different membrane domains and that the integrity of the actin cytoskeleton is essential for acid secretion. Herein, we show that Cdc42 is preferentially distributed to the apical membrane of gastric parietal cells. In addition, we revealed that two Cdc42 regulators, IQGAP1 and IQGAP2, are present in gastric parietal cells. Interestingly, IQGAP2 is polarized to the apical membrane of the parietal cells, whereas IQGAP1 is mainly distributed to the basolateral membrane. An IQGAP peptide that competes with full-length IQGAP proteins for Cdc42-binding in vitro also inhibits acid secretion in streptolysin-O-permeabilized gastric glands. Furthermore, this peptide disrupts the association of IQGAP and Cdc42 with the apical actin cytoskeleton and prevents the apical membrane remodeling upon stimulation. We propose that IQGAP2 forms a link that associates Cdc42 with the apical cytoskeleton and thus allows for activation of polarized secretion in gastric parietal cells. PMID:12631726

  17. Hypothesis--origin of parietal cells: transfer of the H+K+-ATPase gene from parasitic microorganisms to Cnidaria?

    PubMed

    Okabe, S

    1999-09-30

    Parietal cells present in the stomach and terminal ileum secrete a highly-concentrated hydrochloric acid into the lumen. The cells are characterized by the enzyme P-type H+K+-ATPase, which has an alpha-subunit with a high homology (>85%) for the amino acid sequences of frog, mouse and pig stomachs. Gastric H+K+-ATPase also exhibits a high homology to H+-ATPase in yeast and Na+K+-ATPase in many tissues, suggesting origination from a common ancestral ATPase. It is known that parietal cells first appeared in fish and were later expressed in evolutionarily-higher organisms. Primitive organisms, such as Cnidaria and Ctenophora, that possessed digestive organs, but not parietal cells, were abundant in the ocean more than 600 million years ago (Pre-Cambrian period). The author thus hypothesized that the genes of either H+-ATPase or H+K+-ATPase that were present in parasitic microorganisms, such as yeast, were transferred to the interstitial cells of host organisms, such as Cnidaria, eventually leading to the evolution of parietal cells. It appears that although parietal cells in the stomach developed by chance, such cells have greatly contributed to the evolution of advanced organisms, including humans, by affording safe ingestion of a large volume of various foods.

  18. Preservation of the recipient inferior vena cava in liver transplantation.

    PubMed

    Pereira, F; Herrera, J; Mora, N P; Nuño, J; Turrión, V S; Vicente, E; Ardaiz, J

    1994-01-01

    Twenty piggy-back (PB) liver transplantations (LT) were compared with 20 LT performed by the standard technique in order to evaluate whether or not the theoretical haemodynamic advantages of the preservation of the inferior vena cava (IVC) have any impact on the final results of the LT. Statistically significant differences were observed in the duration of the hepatectomy, which was longer for PB LT (192 min vs. 146 min), and in the duration of the anhepatic phase, which was shorter in that group (52 min vs. 76 min). There were no differences in the duration of the complete surgical procedure, consumption of blood products, incidence of postoperative acute renal failure, number of reoperations or survival.

  19. Posttransplant Complex Inferior Venacava Balloon Dilatation After Hepatic Vein Stenting

    SciTech Connect

    Kohli, Vikas; Wadhawan, Manav; Gupta, Subhash; Roy, Vipul

    2010-02-15

    Orthotopic and living related liver transplantation is an established mode of treatment of end-stage liver disease. One of the major causes of postoperative complications is vascular anastomotic stenosis. One such set of such complications relates to hepatic vein, inferior vena cava (IVC), or portal vein stenosis, with a reported incidence of 1-3%. The incidence of vascular complications is reported to be higher in living donor versus cadaveric liver transplants. We encountered a patient with hepatic venous outflow tract obstruction, where the hepatic vein had been previously stented, but the patient continued to have symptoms due to additional IVC obstruction. The patient required double-balloon dilatation of the IVC simultaneously from the internal jugular vein and IVC.

  20. Retrieval of Inferior Vena Cava Filters: Technical Considerations.

    PubMed

    Laws, James L; Lewandowski, Robert J; Ryu, Robert K; Desai, Kush R

    2016-06-01

    Placement of retrievable inferior vena cava filters has seen rapid growth since their introduction into clinical practice. When retrieved, these devices offer the notional benefit of temporary protection from pulmonary embolism related to lower extremity deep venous thrombosis, and mitigation of filter-related deep venous thrombosis. When promptly removed after the indication for mechanical prophylaxis is no longer present, standard endovascular retrieval techniques are frequently successful. However, the majority of these devices are left in place for extended periods of time, which has been associated with greater device-related complications when left in situ, and failure of standard techniques when retrieval is attempted. The development of advanced retrieval techniques has had a positive impact on retrieval of these embedded devices. In this article, technical considerations in the retrieval of such devices, with an emphasis on advanced techniques to facilitate retrieval of embedded devices, are discussed.

  1. Inferior vena caval filter strut perforation causing intramural duodenal haematoma

    PubMed Central

    Williams, Zoheb Berry; Organ, Nicole M.; Deane, Stephen

    2016-01-01

    We present a case of intramural duodenal haematoma caused by inferior vena caval (IVC) filter strut perforation requiring innovative open and endovascular retrieval. A 32-year-old woman presents in shock with dull epigastric pain and non-bilious vomiting. She had previously had an IVC filter for deep venous thrombosis and pulmonary embolism. Computed tomography demonstrated strut perforation into the second part of the duodenum, causing intramural haematoma and duodenal obstruction. Laparotomy facilitated evacuation of the duodenal haematoma, while the IVC filter was retrieved by endovascular means. Causes of duodenal haematoma include blunt trauma, haematologic malignancy, coagulopathy, percutaneous or endoscopic procedures, pancreatic pathology, peptic ulcer disease and aortoenteric fistula. Duodenal haematoma is rare and is usually managed conservatively or by percutaneous drainage. While this patient had a typical presentation, IVC filter strut perforation has not been described in the literature as a cause for duodenal haematoma. PMID:27887016

  2. Indications, Management, and Complications of Temporary Inferior Vena Cava Filters

    SciTech Connect

    Linsenmaier, Ulrich; Rieger, Johannes; Schenk, Franz; Rock, Clemens; Mangel, Eugen; Pfeifer, Klaus Juergen

    1998-11-15

    Purpose: We describe the results of a preliminary prospective study using different recently developed temporary and retrievable inferior vena cava (IVC) filters. Methods: Fifty temporary IVC filters (Guenther, Guenther Tulip, Antheor) were inserted in 47 patients when the required period of protection against pulmonary embolism (PE) was estimated to be less than 2 weeks. The indications were documented deep vein thrombosis (DVT) and temporary contraindications for anticoagulation, a high risk for PE, and PE despite DVT prophylaxis. Results: Filters were removed 1-12 days after placement and nine (18%) had captured thrombi. Complications were one PE during and after removal of a filter, two minor filter migrations, and one IVC thrombosis. Conclusion: Temporary filters are effective in trapping clots and protecting against PE, and the complication rate does not exceed that of permanent filters. They are an alternative when protection from PE is required temporarily, and should be considered in patients with a normal life expectancy.

  3. Commissural functional topography of the inferior colliculus assessed in vitro

    PubMed Central

    Lee, Charles C.; Yanagawa, Yuchio; Imaizumi, Kazuo

    2015-01-01

    The inferior colliculus (IC) receives ascending and descending information from several convergent neural sources. As such, exploring the neural pathway