The Experts below are selected from a list of 52266 Experts worldwide ranked by ideXlab platform
Robert W Stackman - One of the best experts on this subject based on the ideXlab platform.
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the rodent hippocampus is essential for nonspatial object Memory
Current Biology, 2013Co-Authors: Sarah J Cohen, Alcira H Munchow, Lisa M Rios, Gongliang Zhang, Herborg N Asgeirsdottir, Robert W StackmanAbstract:Summary Elucidating the role of the rodent hippocampus in object recognition Memory is critical for establishing the appropriateness of rodents as models of human Memory and for their use in the development of Memory Disorder treatments. In mammals, spatial Memory [1–6] and nonspatial Memory [7, 8] depend upon the hippocampus and associated medial temporal lobe (MTL) structures. Although well established in humans [1, 9], the role of the rodent hippocampus in object Memory remains highly debated due to conflicting findings across temporary and permanent hippocampal lesion studies [10–22] and evidence that the perirhinal cortex may support object Memory [17, 23, 24]. In the current studies, we used intrahippocampal muscimol microinfusions to transiently inactivate the male C57BL/6J mouse hippocampus at distinct stages during the novel object recognition (NOR) task: during object Memory encoding and consolidation, just consolidation, and/or retrieval. We also assessed the effect of temporary hippocampal inactivation when objects were presented in different contexts, thus eliminating the spatial or contextual components of the task. Lastly, we assessed extracellular dorsal hippocampal glutamate efflux and firing properties of hippocampal neurons while mice performed the NOR task. Our results reveal a clear and compelling role of the rodent hippocampus in nonspatial object Memory.
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the rodent hippocampus is essential for nonspatial object Memory
Current Biology, 2013Co-Authors: Sarah J Cohen, Alcira H Munchow, Lisa M Rios, Gongliang Zhang, Herborg N Asgeirsdottir, Robert W StackmanAbstract:Summary Elucidating the role of the rodent hippocampus in object recognition Memory is critical for establishing the appropriateness of rodents as models of human Memory and for their use in the development of Memory Disorder treatments. In mammals, spatial Memory [1–6] and nonspatial Memory [7, 8] depend upon the hippocampus and associated medial temporal lobe (MTL) structures. Although well established in humans [1, 9], the role of the rodent hippocampus in object Memory remains highly debated due to conflicting findings across temporary and permanent hippocampal lesion studies [10–22] and evidence that the perirhinal cortex may support object Memory [17, 23, 24]. In the current studies, we used intrahippocampal muscimol microinfusions to transiently inactivate the male C57BL/6J mouse hippocampus at distinct stages during the novel object recognition (NOR) task: during object Memory encoding and consolidation, just consolidation, and/or retrieval. We also assessed the effect of temporary hippocampal inactivation when objects were presented in different contexts, thus eliminating the spatial or contextual components of the task. Lastly, we assessed extracellular dorsal hippocampal glutamate efflux and firing properties of hippocampal neurons while mice performed the NOR task. Our results reveal a clear and compelling role of the rodent hippocampus in nonspatial object Memory.
Gloria M Grace - One of the best experts on this subject based on the ideXlab platform.
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misidentification syndromes related to face specific area in the fusiform gyrus
Journal of Neurology Neurosurgery and Psychiatry, 2000Co-Authors: Arthur J Hudson, Gloria M GraceAbstract:The “delusional misidentification syndromes” are a group of uncommon and varied Disorders in which, in typical form, the patient thinks that a particular familiar person is someone else or a certain familiar place is a duplicate. Although first identified and considered a Memory Disorder by Pick, evidence in support of this has been difficult to identify. They have been most often seen in various psychotic and organic brain diseases but lesions have been generally diffuse although the right temporal lobe has been implicated. A patient was investigated who abruptly developed a Disorder wherein she misidentified her husband as her deceased sister and claimed that her home was a duplicate of her real home that were typical of Fregoli syndrome and Pick9s reduplicative paramnesia, respectively. A discrete area of brain damage, probably ischaemic, in this patient was seen on MRI in the anterior part of the right fusiform gyrus and a smaller area in the nearby anterior middle and inferior temporal gyri with associated parahippocampal and hippocampal atrophy. A high order nervous system function that is devoted to the identification of faces is located in the adjacent midportion of the fusiform gyrus and a similar locus for environmental scenes, termed the parahippocampal place area, is present in the bordering parahippocampal gyrus. The misidentification phenomena in this case can be explained by disruption of the connections of these highly specialised areas with the most anterior inferior and medial part of the right temporal lobe where long term Memory and mechanisms for the retrieval of information that are required for the visual recognition of faces and scenes are stored.
Suncica Lah - One of the best experts on this subject based on the ideXlab platform.
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accelerated long term forgetting is not evident in adults with genetic generalized epilepsy irrespective of the paradigm used
Epilepsy & Behavior, 2020Co-Authors: Jessica Elise Beilharz, Zoe Thayer, Armin Nikpour, Suncica LahAbstract:Abstract Accelerated long-term forgetting (ALF) is a recently discovered Memory Disorder characterized by intact acquisition and retention over short delays, followed by abnormally fast rates of forgetting. Accelerated long-term forgetting has been repeatedly found in children, but not in adults, with genetic generalized epilepsy (GGE). It is possible that this discrepancy is due to a difference in paradigms used in these studies. The current study aimed to determine whether adults with GGE displayed ALF using two paradigms, one that required complete learning and another one that did not. In addition, we explored the relationships with everyday Memory difficulties, working Memory, mood, and epilepsy variables. Fourteen adults with GGE were compared with 16 healthy controls on two verbal Memory tests: a modified version of the California Verbal Learning Test learned to a criterion of 100% (complete learning) and Logical Memory from the Wechsler Memory Scale (Fourth Edition) presented only once (incomplete learning). Recall was tested at 2 min, 30 min, and 1 week, and recognition at 1 week only. Working Memory, everyday Memory, and mood were also assessed. We found no evidence of ALF on either of the two verbal Memory paradigms on recall or recognition tests although patients displayed significantly poorer working Memory. Moreover, patients with GGE reported significantly more Memory difficulties in everyday life, and these were associated with greater mood disturbances but not with Memory tests scores. Greater number of antiepileptic drugs and epilepsy severity also related to Memory scores on some tests. Our study suggests that a difference in paradigms used to investigate ALF in children and adults with GGE is unlikely to explain the differences in findings. The study tentatively raises a hypothesis that developmental factors may play a role in ALF in patients with GGE; children with GGE may grow out of ALF. Nevertheless, this hypothesis would need to be tested in a longitudinal study that would follow patients from childhood to early adulthood.
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longitudinal study of accelerated long term forgetting in children with genetic generalized epilepsy evidence of ongoing deficits
Cortex, 2017Co-Authors: Jasmin Graysoncollins, Michael B Gascoigne, Belinda Barton, Richard M Webster, Deepak Gill, Suncica LahAbstract:Accelerated long-term forgetting (ALF) is a recently described Memory Disorder characterised by adequate recall after short, but not long delays. Currently, the prevailing conceptualisation of ALF is of a seizure related phenomenon. The main aim of this study was to assess whether ALF subsides as epilepsy severity and seizures abate in children with genetic generalized epilepsy (GGE). Eighteen children with GGE were compared over time to 29 healthy controls on a range of cognitive measures. The primary outcome was a modified version of the California Verbal Learning Test for Children with a long delay (seven day) recall component. At approximately two years follow up, ALF was apparent, although epilepsy severity subsided and seizures resolved in many children. This result contrasts with the dominant conceptualisation of ALF being a seizure related phenomenon. Moreover, at follow-up, worse recall at the long delay was related to greater epilepsy severity at baseline and earlier age of seizure onset, but not to being seizure free at follow-up. While at follow-up worse recall at the long delay related to the worse baseline recall at the long delay, this recall did not relate to scores obtained on standardised Memory tests at baseline. Our study suggests that ALF may not be seizure related and identifies factors associated with risk of ALF in children with GGE.
John R Hodges - One of the best experts on this subject based on the ideXlab platform.
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topographic amnesia spatial Memory Disorder perceptual dysfunction or category specific semantic Memory impairment
Journal of Neurology Neurosurgery and Psychiatry, 1996Co-Authors: Rosaleen A Mccarthy, Jonathan Evans, John R HodgesAbstract:A 60 year old patient, SE, who presented with a severe difficulty in finding his way around previously familiar environments and a mild prosopagnosia is described. SE had herpes simplex encephalitis resulting in selective right temporal lobe damage. He showed normal spatial learning, but was severely imparied in his ability to recognise pictures of buildings and landmarks. The Disorder was not confined to the visual modality, but rather involved a loss of knowledge about famous buildings and landmarks when tested from their spoken name. SE was contrasted with a more severely prosopagnosic patient, PHD, who showed normal ability to recognise buildings and landmarks, indicating that recognition of people dissociates from recognition of buildings/landmarks. It is concluded that SE's failure of place knowledge represents a category specific supramodal semantic Memory impairment.
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is semantic Memory consistently impaired early in the course of alzheimer s disease neuroanatomical and diagnostic implications
Neuropsychologia, 1995Co-Authors: John R Hodges, Karalyn PattersonAbstract:To establish whether semantic Memory is consistently impaired in patients with very mild dementia of Alzheimer's type (DAT), we assessed episodic and semantic Memory in 52 patients with DAT who were divided into three sub-groups according to dementia severity on the Mini-Mental State Examination (minimal > 23, mild 17-23 and moderate < 17) and 24 matched controls. The minimal group showed impairment on the following semantic Memory measures: category fluency, naming of line drawings, naming to verbal description, answering semantic feature questions and a non-verbal picture-picture matching task (the Pyramids and Palm Trees Test). The mild and moderate groups showed additional deficits on picture sorting and word-picture matching tests. Within the minimal and mild groups there was, however, considerable heterogeneity. While some patients showed a consistent impairment across all of the semantic Memory tests, others were impaired on only on a subset of these tests and a few even performed flawlessly. In contrast, all patients showed a profound deficit in episodic Memory: delayed recall of new verbal and non-verbal material appears to be a particularly sensitive marker of early DAT. These data are in keeping with recent neuropathological studies demonstrating that the transentorhinal region is consistently involved at a very early stage. Lesions in this site cause a functional disconnection of the hippocampus, and hence a profound episodic Memory Disorder. The fact that many, but not all, patients with early disease also show impairment of semantic Memory suggests that damage to the transentorhinal region is not sufficient to produce significant disruption of semantic Memory. Such disruption reliably occurs, we hypothesize, only when the pathology extends to the temporal neocortex proper.
Arthur J Hudson - One of the best experts on this subject based on the ideXlab platform.
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misidentification syndromes related to face specific area in the fusiform gyrus
Journal of Neurology Neurosurgery and Psychiatry, 2000Co-Authors: Arthur J Hudson, Gloria M GraceAbstract:The “delusional misidentification syndromes” are a group of uncommon and varied Disorders in which, in typical form, the patient thinks that a particular familiar person is someone else or a certain familiar place is a duplicate. Although first identified and considered a Memory Disorder by Pick, evidence in support of this has been difficult to identify. They have been most often seen in various psychotic and organic brain diseases but lesions have been generally diffuse although the right temporal lobe has been implicated. A patient was investigated who abruptly developed a Disorder wherein she misidentified her husband as her deceased sister and claimed that her home was a duplicate of her real home that were typical of Fregoli syndrome and Pick9s reduplicative paramnesia, respectively. A discrete area of brain damage, probably ischaemic, in this patient was seen on MRI in the anterior part of the right fusiform gyrus and a smaller area in the nearby anterior middle and inferior temporal gyri with associated parahippocampal and hippocampal atrophy. A high order nervous system function that is devoted to the identification of faces is located in the adjacent midportion of the fusiform gyrus and a similar locus for environmental scenes, termed the parahippocampal place area, is present in the bordering parahippocampal gyrus. The misidentification phenomena in this case can be explained by disruption of the connections of these highly specialised areas with the most anterior inferior and medial part of the right temporal lobe where long term Memory and mechanisms for the retrieval of information that are required for the visual recognition of faces and scenes are stored.