The Experts below are selected from a list of 9219 Experts worldwide ranked by ideXlab platform
Eva Irle - One of the best experts on this subject based on the ideXlab platform.
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Posterior Parahippocampal Gyrus lesions in the human impair egocentric learning in a virtual environment
European Journal of Neuroscience, 2006Co-Authors: Godehard Weniger, Eva IrleAbstract:Functional imaging studies have shown that the posterior Parahippocampal Gyrus (PHG) is involved in allocentric (world-centered) object and scene recognition. However, the putative role of the posterior PHG in egocentric (body-centered) spatial memory has received only limited systematic investigation. Thirty-one subjects with pharmacoresistant medial temporal lobe epilepsy (TLE) and temporal lobe removal were compared with 19 matched healthy control subjects on a virtual reality task affording the navigation in a virtual maze (egocentric memory). Lesions of the hippocampus and PHG of TLE subjects were determined by three-dimensional magnetic resonance imaging volumetric assessment. The results indicate that TLE subjects with right-sided posterior PHG lesions were impaired on virtual maze acquisition when compared with controls and TLE subjects with anterior PHG lesions. Larger posterior PHG lesions were significantly related to stronger impairments in virtual maze performance. Our results point to a role of the right-sided posterior PHG for the representation and storage of egocentric information. Moreover, access to both allocentric and egocentric streams of spatial information may enable the posterior PHG to construct a global and comprehensive representation of spatial environments.
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Impaired associative memory in temporal lobe epilepsy subjects after lesions of hippocampus, Parahippocampal Gyrus, and amygdala.
Hippocampus, 2004Co-Authors: Godehard Weniger, Katrin Boucsein, Eva IrleAbstract:There has been growing interest in the differential role of medial temporal lobe structures in learning and memory. The goal of the present study was to clarify how lesions of hippocampus, Parahippocampal Gyrus, and amygdala interfere with associative learning and memory. Thirty subjects with pharmacoresistant medial temporal lobe epilepsy (TLE) and temporal lobe removal were compared with 30 matched healthy control subjects. A set of neuropsychological test measures and an associative learning task requiring the learning and recall of objects and faces were administered. The lesions of hippocampus, Parahippocampal Gyrus, amygdala, and fusiform Gyrus of TLE subjects were determined by three-dimensional magnetic resonance imaging (3-D MRI) volumetric assessment. The results indicate that TLE subjects with combined large hippocampal lesions, large Parahippocampal Gyrus (i.e., perirhinal/entorhinal) lesions, and large amygdala lesions learned and recalled the associative task significantly worse than control subjects or subjects with small lesions of the hippocampus, Parahippocampal Gyrus, and amygdala. Regression analysis revealed that larger lesions of the Parahippocampal Gyrus (i.e., perirhinal/entorhinal cortices) were significantly related to increasing deficits on the task, and that hippocampal and amygdala lesion size did not significantly improve the prediction. Our results suggest that perirhinal and entorhinal cortices may contribute predominantly to the associative learning and recall of objects and faces. © 2004 Wiley-Liss, Inc.
Reisa A. Sperling - One of the best experts on this subject based on the ideXlab platform.
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the Parahippocampal Gyrus links the default mode cortical network with the medial temporal lobe memory system
Human Brain Mapping, 2014Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
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The Parahippocampal Gyrus links the default‐mode cortical network with the medial temporal lobe memory system
Human brain mapping, 2013Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
Andrew Ward - One of the best experts on this subject based on the ideXlab platform.
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the Parahippocampal Gyrus links the default mode cortical network with the medial temporal lobe memory system
Human Brain Mapping, 2014Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
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The Parahippocampal Gyrus links the default‐mode cortical network with the medial temporal lobe memory system
Human brain mapping, 2013Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
Masayoshi Kurachi - One of the best experts on this subject based on the ideXlab platform.
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temporal lobe gray matter in schizophrenia spectrum a volumetric mri study of the fusiform Gyrus Parahippocampal Gyrus and middle and inferior temporal gyri
Schizophrenia Research, 2006Co-Authors: Tsutomu Takahashi, Shi-yu Zhou, Ryoichiro Tanino, Michio Suzuki, Yasuhiro Kawasaki, Hirofumi Hagino, Hikaru Seto, Masayoshi KurachiAbstract:Abstract Although several brain morphologic studies have suggested abnormalities in the temporal regions to be a common indicator of vulnerability for the schizophrenia spectrum, less attention has been paid to temporal lobe structures other than the superior temporal Gyrus or the medial temporal region. In this study, we investigated the volume of gray matter in the fusiform Gyrus, the Parahippocampal Gyrus, the middle temporal Gyrus, and the inferior temporal Gyrus using magnetic resonance imaging in 39 schizotypal disorder patients, 65 schizophrenia patients, and 72 age and gender matched healthy control subjects. The anterior fusiform Gyrus was significantly smaller in the schizophrenia patients than the control subjects but not in the schizotypal disorder patients, while the volume reduction of the posterior fusiform Gyrus was common to both disorders. Volumes for the middle and inferior temporal gyri or the Parahippocampal Gyrus did not differ between groups. These findings suggest that abnormalities in the posterior region of the fusiform Gyrus are, as have been suggested for the superior temporal Gyrus or the amygdala/hippocampus, prominent among the temporal lobe structures as a common morphologic substrate for the schizophrenia spectrum, whereas more widespread alterations involving the anterior region might be associated with the development of full-blown schizophrenia.
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Verbal memory deficits in a preadolescent case of lesions of the left Parahippocampal Gyrus associated with a benign tumor.
Progress in neuro-psychopharmacology & biological psychiatry, 2006Co-Authors: Tomiki Sumiyoshi, Hirofumi Hagino, Chika Sumiyoshi, Shigeru Nohara, Shinsaku Hasegawa, Naoya Kuwayama, Shunro Endo, Masayoshi KurachiAbstract:The authors report cognitive functions of a 13-year-old boy with a cavernous angioma occupying the posterior left Parahippocampal Gyrus (PHG) and part of the left fusiform Gyrus but not hippocampus. Neuropsychological examinations soon after the removal of the tumor showed selective deficits in semantic memory function, as evaluated by the Category Fluency Task and the Wechsler Memory Scale-Revised, while visual memory, attention, and IQ were not affected. These observations suggest the involvement of the PHG in the processing of semantic memory and provide an insight into the neural substrates underlying the distinct cognitive deficits in some of the psychiatric diseases such as schizophrenia.
Willem Huijbers - One of the best experts on this subject based on the ideXlab platform.
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the Parahippocampal Gyrus links the default mode cortical network with the medial temporal lobe memory system
Human Brain Mapping, 2014Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
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The Parahippocampal Gyrus links the default‐mode cortical network with the medial temporal lobe memory system
Human brain mapping, 2013Co-Authors: Andrew Ward, Aaron P. Schultz, Willem Huijbers, Koene R. A. Van Dijk, Trey Hedden, Reisa A. SperlingAbstract:The default-mode network (DMN) is a distributed functional-anatomic network implicated in supporting memory. Current resting-state functional connectivity studies in humans remain divided on the exact involvement of medial temporal lobe (MTL) in this network at rest. Notably, it is unclear to what extent the MTL regions involved in successful memory encoding are connected to the cortical nodes of the DMN during resting-state. Our findings using functional connectivity MRI analyses of resting-state data indicate that the Parahippocampal Gyrus (PHG) is the primary hub of the DMN in the MTL during resting-state. Also, connectivity of the PHG is distinct from connectivity of hippocampal regions identified by an associative memory encoding task. We confirmed that several hippocampal encoding regions lack significant functional connectivity with cortical DMN nodes during resting-state. Additionally, a mediation analysis showed that resting-state connectivity between the hippocampus and posterior cingulate cortex — a major hub of the DMN — is indirect and mediated by the PHG. Our findings support the hypothesis that the MTL memory system represents a functional sub-network that relates to the cortical nodes of the DMN through Parahippocampal functional connections.
