Paper Info
Title
Network reconfiguration and working memory impairment in mesial temporal lobe epilepsy.
Abstract
Mesial temporal lobe epilepsy (mTLE) is the most prevalent form of focal epilepsy, and hippocampal sclerosis (HS) is considered the most frequent associated pathological finding. Recent connectivity studies have shown that abnormalities, either structural or functional, are not confined to the affected hippocampus, but can be found in other connected structures within the same hemisphere, or even in the contralesional hemisphere. Despite the role of hippocampus in memory functions, most of these studies have explored network properties at resting state, and in some cases compared connectivity values with neuropsychological memory scores. Here, we measured magnetoencephalographic responses during verbal working memory (WM) encoding in left mTLE patients and controls, and compared their effective connectivity within a frontotemporal network using dynamic causal modelling. Bayesian model comparison indicated that the best model included bilateral, forward and backward connections, linking inferior temporal cortex (ITC), inferior frontal cortex (IFC), and the medial temporal lobe (MTL). Test for differences in effective connectivity revealed that patients exhibited decreased ipsilesional MTL-ITC backward connectivity, and increased bidirectional IFC-MTL connectivity in the contralesional hemisphere. Critically, a negative correlation was observed between these changes in patients, with decreases in ipsilesional coupling among temporal sources associated with increases contralesional frontotemporal interactions. Furthermore, contralesional frontotemporal interactions were inversely related to task performance and level of education. The results demonstrate that unilateral sclerosis induced local and remote changes in the dynamic organization of a distributed network supporting verbal WM. Crucially, pre-(peri) morbid factors (educational level) were reflected in both cognitive performance and (putative) compensatory changes in physiological coupling.
Year
DOI
Venue
2013
10.1016/j.neuroimage.2013.01.036
NeuroImage
Keywords
Field
DocType
Hippocampal sclerosis,Working memory,Connectivity,Dynamic causal modelling,Temporal lobe epilepsy
Developmental psychology,Neuroscience,Working memory,Resting state fMRI,Psychology,Cognitive psychology,Effects of sleep deprivation on cognitive performance,Magnetoencephalography,Hippocampal sclerosis,Hippocampus,Temporal lobe,Dynamic causal modelling
Journal
Volume
ISSN
Citations 
72
1053-8119
1
PageRank 
References 
Authors
0.36
12
9
Name
Order
Citations
PageRank
Pablo Campo173.59
Marta I Garrido21049.16
R MORAN343826.66
Irene García-Morales410.36
Claudia Poch520.74
Rafael Toledano610.36
Antonio Gil-Nagel710.36
Raymond J Dolan841949.74
Karl J Friston94455347.58