Spatial variability of functional brain networks in early-blind and sighted subjects

Abstract

To further the understanding how the human brain adapts to early-onset blindness, we searched in early-blind and normally-sighted subjects for functional brain networks showing the most and least spatial variabilities across subjects. We hypothesized that the functional networks compensating for early-onset blindness undergo cortical reorganization. To determine whether reorganization of functional networks affects spatial variability, we used functional magnetic resonance imaging to compare brain networks, derived by independent component analysis, of 7 early-blind and 7 sighted subjects while they rested or listened to an audio drama. In both conditions, the blind compared with sighted subjects showed more spatial variability in a bilateral parietal network (comprising the inferior parietal and angular gyri and precuneus) and in a bilateral auditory network (comprising the superior temporal gyri). In contrast, a vision-related left-hemisphere-lateralized occipital network (comprising the superior, middle and inferior occipital gyri, fusiform and lingual gyri, and the calcarine sulcus) was less variable in blind than sighted subjects. Another visual network and a tactile network were spatially more variable in the blind than sighted subjects in one condition. We contemplate whether our results on inter-subject spatial variability of brain networks are related to experience-dependent brain plasticity, and we suggest that auditory and parietal networks undergo a stronger experience-dependent reorganization in the early-blind than sighted subjects while the opposite is true for the vision-related occipital network.

Spatial Variance in Resting fMRI Networks of Schizophrenia Patients: An Independent Vector Analysis

“…The goal of these models is to estimate sources (ie, networks) so that each source can be compared across subjects while maintaining independence between the different sources. 10 To our knowledge, there have been few studies focused on the spatial variability of resting networks 11 and none among schizophrenia subjects. Given that we do expect considerable spatial variability, there is a need for approaches that can effectively incorporate this variability in conjunction with studies assessing this variability.…”

Primary visual cortical remapping in patients with inherited peripheral retinal degeneration

“…Nonetheless, both studies focused on cross-modal plasticity mechanisms and not in characterizing simultaneously the structure and function of visual cortical regions in the context of specific changes triggered by a retinal disorder. Additionally, the majority of reports on structural changes combine several ophthalmological conditions involving distinct mechanisms, which may hinder the understanding of specific brain changes triggered by a particular disease (Anurova et al, 2014, Boldt et al, 2014, Dietrich et al, 2013, Erika et al, 2014, Lee et al, 2014, Lewald and Getzmann, 2013, Park et al, 2009, Plank et al, 2011, Renier et al, 2013, Wang et al, 2014, Weaver et al, 2013, Xie et al, 2012). Previous studies with advanced stage patients with glaucoma and macular degeneration (Bogorodzki et al, 2014, Boucard et al, 2009, Chen et al, 2013, Hernowo et al, 2014, Plank et al, 2011, Yu et al, 2014, Zikou et al, 2012) and blind participants (Anurova et al, 2014, Jiang et al, 2009, Pan et al, 2007, Park et al, 2009, Ptito et al, 2008) reported reduced gray matter volume in the occipital cortex.…”

Reduction of Interhemispheric Functional Brain Connectivity in Early Blindness: A Resting-State fMRI Study

“…A previous study demonstrated that early blindness showed resting-state correlations between V1 and V2/V3 in retinotopic pattern [7]. There are also propositions that early blind patients exhibit stronger auditory and parietal networks and weaker vision-related occipital networks compared with sighted subjects [8]. Meanwhile, the congenital blindness (CB) and the late blindness (LB) showed decreased short- and long-range functional connectivity densities in the primary visual cortex (V1) [9].…”