A distinct electrophysiological signature for synaesthesia that is independent of individual differences in sensory sensitivity

People with synaesthesia have been reported to show atypical electrophysiological responses certain simple sensory stimuli, even if these stimuli are not inducers of synaesthesia. However, it is unclear whether this constitutes a neural marker that relatively specific or reflects some other trait co-occurs synaesthesia, but it. One candidate sensitivity (e.g., strong aversion lights and sounds, ‘sensory overload’) which feature both autism varies greatly in the neurotypical population. Using visual evoked-potentials (to varying spatial frequency) auditory-evoked potentials auditory frequency), we found synaesthetes had modulated evoked-potential around P1/N1 (emanating from fusiform cortex), greater N1, as well differences time-frequency domain (increased alpha beta induced power for stimuli). This was distinct non-synaesthetes. By contrast, no significant were linked variation sensitivity.