JLE

Epileptic Disorders

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The link between structural connectivity and neurocognition illustrated by focal epilepsy Volume 20, numéro 2, April 2018

Figure 1

Illustration of the main association fascicles involved in language and verbal memory networks (adapted from Catani and Thiebaut de Schotten [2012] and Catani et al. [2013], with permission).

(A) Representation of the language network according to Mesulam (2000); thesuperior longitudinal fascicle (SLF) and the arcuate fascicle (Arc) are involved in the dorsalphonological pathway, described in the Duffau model (Duffau, 2008) and connect Broca's area toWernicke's area, among others.

(B) The semantic ventral pathway forrecognising or identifying objects and faces (Mesulam, 2000; Duffau et al., 2014); this concentratesinferior fascicles -the inferior longitudinal fascicle (ILF) and inferior fronto-occipital fascicle(IFOF)- that converge towards the temporal pole.

(C) Illustration of the memory-emotionnetwork according to Mesulam (2000); this concerns a vast network involving the fornix (Fox),the cingulum (Cing), and the uncinate (Unc) fascicles. Usually, language-verbal memorynetworks are essentially lateralized in the left hemisphere (LH).

Figure 2

Illustration of the patterns of functional reorganization observed in epileptic patients (reproduced from Baciu and Perrone-Bertolotti [2015], with permission).

At theinter-hemispheric level, there is involvement or displacement of critical areas for language in thecontralateral hemisphere (most often in homologous areas of the right hemisphere); this may becomplete (A), or partial (B). At the intra-hemispheric level (C),there isadditional recruitment or displacement of linguistic regions beyond the classic “eloquentareas” within the dominant hemisphere.