Steady-state visual evoked potentials in deaf and hearing individuals indicate an experience-dependence of the optimal driving rate

Sensory cortices differ in their optimal driving rate: The visual system is best entrained with periodic stimuli at rates around 10 Hz, the tactile system at rates between 20 and 27 Hz, and the auditory system at rates around 40 Hz. The present study recorded steady-state visual evoked potentials (SSVEP) from congenitally deaf adults (n = 23) and hearing controls (n = 23) to test whether the enhanced reliance on the visual system of deaf individuals affects the optimal driving rate of the visual cortex (intramodal plasticity). Moreover, we hypothesized that the SSVEPs have a more fronto-central distribution in deaf individuals, compatible with the idea of crossmodal plasticity. The luminance of the visual stimuli was periodically modulated at 12, 21 and 40 Hz. This manipulation allowed us to test whether crossmodal recruitment is observed at the best driving rate typically associated with the input modality (the visual system) or at the best driving rate typically associated with the crossmodally entrained cortex (the auditory system). The optimal driving rate at occipital electrodes was 12 and 21 Hz in the deaf and 12 Hz in the hearing participants. At fronto-central sites, the best entrainment in the deaf participants was observed for the 21 Hz stimulation. These results suggest that experience shapes the cortical operation characteristics (intramodal plasticity). Crossmodal activation emerged at a driving rate typical for the deaf group’s visual system rather than at a rate typical for the auditory system of hearing individuals.