Short-term crossmodal plasticity of the auditory steady-state response in blindfolded sighted individuals.

This study investigated the effect of short-term visual deprivation on auditory steady-state response (ASSR) to amplitude-modulated tones. Magnetoencephalography data were acquired while subjects performed an auditory detection task under both monaural and dichotic presentation conditions. Analyses were performed on the spectral power, mean amplitudes and dipole positions of the ASSR at the onset of blindfolding, as well as after 2, 4 and 6 h of visual deprivation. Results show a modulation of the spectral power of the ASSR at the frequencies that were present in the stimulus after 6 h of sensory deprivation, and this was especially true for the dichotic condition. Moreover, participants showed two spectral peaks in the occipital cortex at the end of the visual deprivation period, a phenomenon normally observed in the auditory cortex. Our results shed light not only on the timeline associated with short-term crossmodal recruitment of input-deprived sensory cortices but also demonstrate that the visual cortex can display auditory cortex-like functioning in response to the ASSR. Importantly, our results also highlight the importance of taking into consideration individual differences when investigating crossmodal plastic phenomena. Indeed, the occipital spectral peaks were only observed in half the subjects following short-term deprivation.