title: Interplay between Heightened Temporal Variability of Spontaneous Brain Activity and Task-Evoked Hyperactivation in the Blind.
abstract: The brain's functional organization can be altered by visual deprivation. This is observed by comparing blind and sighted people's activation response to tactile discrimination tasks, like braille reading. Where, the blind have higher activation than the sighted upon tactile discrimination tasks, especially high activation difference is seen in ventral occipitotemporal (vOT) cortex. However, it remains unknown, whether this vOT hyperactivation is related to alteration of spontaneous activity. To address this question, we examined 16 blind subjects, 19 low-vision individuals, and 21 normally sighted controls using functional magnetic resonance imaging (fMRI). Subjects were scanned in resting-state and discrimination tactile task. In spontaneous activity, when compared to sighted subjects, we found both blind and low vision subjects had increased local signal synchronization and increased temporal variability. During tactile tasks, compared to sighted subjects, blind and low-vision subject's vOT had stronger tactile task-induced activation. Furthermore, through inter-subject partial correlation analysis, we found temporal variability is more related to tactile-task activation, than local signal synchronization's relation to tactile-induced activation. Our results further support that vision impairment induces vOT cortical reorganization. The hyperactivation in the vOT during tactile stimulus processing in the blind may be related to their greater dynamic range of spontaneous activity.
authors.affiliation: School of Life Science, South China Normal University Guangzhou, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Dai
authors.affiliation: Institute of Mental Health Research, University of Ottawa Ottawa, ON, Canada.
authors.forename: Zirui
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University Hangzhou, China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Tu
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University Hangzhou, China.
authors.forename: Luoyu
authors.initials: L
authors.lastname: Wang
authors.affiliation: Faculty of Science, University of Ottawa Ottawa, ON, Canada.
authors.forename: Sean
authors.initials: S
authors.lastname: Tanabe
authors.affiliation: Center for Cognition and Brain Disorders, Hangzhou Normal University Hangzhou, China.
authors.forename: Xuchu
authors.initials: X
authors.lastname: Weng
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of SciencesBeijing, China; Department of Psychology, University of MinnesotaMinneapolis, MN, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: He
authors.affiliation: School of Life Science, South China Normal University Guangzhou, China.
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Li
keywords: blind; fMRI; spontaneous brain activity; temporal variability; ventral occipitotemporal cortex; visual deprivation