Abstract
Surprisingly, after extensive cortical resections, children, but not adults, maintain or regain many aspects of cognitive function. One possible mechanism that might facilitate functional remapping or compensation is through changes in the functional connectivity between brain areas. In this case series investigation, we recorded BOLD responses from patients with drug-resistant epilepsy, prior to and/or after surgical resection (n = 8, 4 left and 4 right affected hemispheres, ages: 7-22), and controls at two scanner sites (n = 31, ages: 9-32) as they viewed and listened to an 11-minute segment of a movie twice. The intact hemisphere of the patients and both hemispheres of controls were parcellated into 180 regions and harmonization was used to account for site differences. In an analysis with age and gender as covariates, there were no significant differences between the individual patients and the hemisphere-matched controls in the average univariate activation profile. To examine the functional connectivity across the whole intact hemisphere, we aggregated the 180 regions into 22 networks (Glasser et al., 2017) and assessed the voxelwise functional connectivity (FC) within and between each network for each patient using linear mixed effects modelling. Two main results emerged: 1) in the pre-surgical cases (n = 2), there were no differences in either within- or between-network FC, and 2) all post-surgical case studies (n = 7) showed significant interactions between network type (within or between) and group (patient or control). Qualitatively, relative to controls, 6 of the 7 cortical resection patients demonstrated divergence in the within-group correlations and the remaining patient had higher between-group correlations. These findings reveal the specificity in the FC changes following cortical resection that are independent of affected hemisphere. The large-scale reorganization of networks in the intact, preserved hemisphere might reflect emergent plasticity in the service of maintained and/or retained cognitive function.