Visual stimuli activate auditory cortex in deaf subjects: evidence from MEG

TLDR

fMRI studies show that visual stimuli activate auditory cortex in deaf individuals, but the timing of this activation remains unclear due to fMRI’s low temporal resolution. We used magnetoencephalography to assess whether the auditory cortex in deaf participants responds to visual stimuli during early processing. Visual activity appeared in the auditory cortex of deaf participants, within 100–400 ms after stimulus onset and mainly over the right hemisphere, whereas hearing participants showed no such activation, supporting cross‑modal reorganization.

Abstract

Studies using fMRI have demonstrated that visual stimuli activate auditory cortex in deaf subjects. Given the low temporal resolution of fMRI, it is uncertain whether this activation is associated with initial stimulus processing. Here, we used MEG in deaf and hearing subjects to evaluate whether auditory cortex, devoid of its normal input, comes to serve the visual modality early in the course of stimulus processing. In line with previous findings, visual activity was observed in the auditory cortex of deaf, but not hearing, subjects. This activity occurred within 100–400 ms of stimulus presentation and was primarily over the right hemisphere. These results add to the mounting evidence that removal of one sensory modality in humans leads to neural reorganization of the remaining modalities.