Open AccessExtratemporal functional connectivity impairments at rest are related to memory performance in mesial temporal epilepsy
Author(s) -
Doucet Gaëlle,
Osipowicz Karol,
Sharan Ashwini,
Sperling Michael R.,
Tracy Joseph I.
Publication year - 2013
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.22059
Subject(s) - cingulum (brain) , psychology , episodic memory , neuroscience , temporal lobe , epilepsy , hippocampal sclerosis , lateralization of brain function , neuroanatomy of memory , verbal memory , recall , white matter , cognition , explicit memory , magnetic resonance imaging , cognitive psychology , medicine , fractional anisotropy , radiology
Mesial temporal lobe epilepsy (MTLE) is the most frequent form of focal epilepsy. At rest, there is evidence that brain abnormalities in MTLE are not limited to the epileptogenic region, but extend throughout the whole brain. It is also well established that MTLE patients suffer from episodic memory deficits. Thus, we investigated the relation between the functional connectivity seen at rest in fMRI and episodic memory impairments in MTLE. We focused on resting state BOLD activity and evaluated whether functional connectivity (FC) differences emerge from MTL seeds in left and right MTLE groups, compared with healthy controls. Results revealed significant FC reductions in both patient groups, localized in angular gyri, thalami, posterior cingulum and medial frontal cortex. We found that the FC between the left non‐pathologic MTL and the medial frontal cortex was positively correlated with the delayed recall score of a non‐verbal memory test in right MTLE patients, suggesting potential adaptive changes to preserve this memory function. In contrast, we observed a negative correlation between a verbal memory test and the FC between the left pathologic MTL and posterior cingulum in left MTLE patients, suggesting potential functional maladaptative changes in the pathologic hemisphere. Overall, the present study provides some indication that left MTLE may be more impairing than right MTLE patients to normative functional connectivity. Our data also indicates that the pattern of extra‐temporal FC may vary as a function of episodic memory material and each hemisphere's capacity for cognitive reorganization. Hum Brain Mapp 34:2202–2216, 2013 . © 2012 Wiley Periodicals, Inc.