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Congenitally blind
Functional connectivity
Oscillations
Training
Working memory
Abstract:
Congenitally blind individuals have been shown to activate the visual cortex during non-visual tasks. The
neuronal mechanisms of such cross-modal activation are not fully understood. Here, we used an auditory working
memory training paradigm in congenitally blind and in sighted adults. We hypothesized that the visual cortex gets
integrated into auditory working memory networks, after these networks have been challenged by training. The
spectral profile of functional networks was investigated which mediate cross-modal reorganization following
visual deprivation. A training induced integration of visual cortex into task-related networks in congenitally blind
individuals was expected to result in changes in long-range functional connectivity in the theta-, beta- and gamma
band (imaginary coherency) between visual cortex and working memory networks. Magnetoencephalographic
data were recorded in congenitally blind and sighted individuals during resting state as well as during a voicebased
working memory task; the task was performed before and after working memory training with either
auditory or tactile stimuli, or a control condition. Auditory working memory training strengthened theta-band
(2.5–5 Hz) connectivity in the sighted and beta-band (17.5–22.5 Hz) connectivity in the blind. In sighted participants,
theta-band connectivity increased between brain areas typically involved in auditory working memory
(inferior frontal, superior temporal, insular cortex). In blind participants, beta-band networks largely emerged
during the training, and connectivity increased between brain areas involved in auditory working memory and as
predicted, the visual cortex. Our findings highlight long-range connectivity as a key mechanism of functional
reorganization following congenital blindness, and provide new insights into the spectral characteristics of
functional network connectivity.
