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Neural correlates of working memory in Temporal Lobe Epilepsy--an fMRI study.

Stretton, J; Winston, G; Sidhu, M; Centeno, M; Vollmar, C; Bonelli, S; Symms, M; ... Thompson, PJ; + view all (2012) Neural correlates of working memory in Temporal Lobe Epilepsy--an fMRI study. Neuroimage , 60 (3) 1696 - 1703. 10.1016/j.neuroimage.2012.01.126. Green open access

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Abstract

It has traditionally been held that the hippocampus is not part of the neural substrate of working memory (WM), and that WM is preserved in Temporal Lobe Epilepsy (TLE). Recent imaging and neuropsychological data suggest this view may need revision. The aim of this study was to investigate the neural correlates of WM in TLE using functional MRI (fMRI). We used a visuo-spatial 'n-back' paradigm to compare WM network activity in 38 unilateral hippocampal sclerosis (HS) patients (19 left) and 15 healthy controls. WM performance was impaired in both left and right HS groups compared to controls. The TLE groups showed reduced right superior parietal lobe activity during single- and multiple-item WM. No significant hippocampal activation was found during the active task in any group, but the hippocampi progressively deactivated as the task demand increased. This effect was bilateral for controls, whereas the TLE patients showed progressive unilateral deactivation only contralateral to the side of the hippocampal sclerosis and seizure focus. Progressive deactivation of the posterior medial temporal lobe was associated with better performance in all groups. Our results suggest that WM is impaired in unilateral HS and the underlying neural correlates of WM are disrupted. Our findings suggest that hippocampal activity is progressively suppressed as the WM load increases, with maintenance of good performance. Implications for understanding the role of the hippocampus in WM are discussed.

Type: Article
Title: Neural correlates of working memory in Temporal Lobe Epilepsy--an fMRI study.
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.neuroimage.2012.01.126
Publisher version: http://dx.doi.org/10.1016/j.neuroimage.2012.01.126
Language: English
Additional information: This work is licensed under the Creative Commons Attribution License, Attribution 3.0 Unported (CC BY 3.0) http://creativecommons.org/licenses/by/3.0/ which permits unrestricted use, distribution, and reproduction in any medium. However, you must attribute the work to the author (but not in any way that suggests that they endorse you or your use of the work).
Keywords: Adult, Epilepsy, Temporal Lobe, Female, Hippocampus, Humans, Magnetic Resonance Imaging, Male, Memory, Short-Term, Middle Aged, Nerve Net, Sclerosis, Statistics as Topic, Temporal Lobe, Young Adult
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Clinical and Experimental Epilepsy
URI: https://discovery.ucl.ac.uk/id/eprint/1342065
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