Cortical encoding of aperiodic and periodic speech sounds: Evidence for distinct neural populations

► Cortical tuning to vowel periodicity was probed with stimulus-specific adaptation. ► Results on the auditory N1m revealed aperiodicity-related activation. ► Periodicity-sensitivity of the N1m was modulated by the interstimulus interval. ► N1m remained periodicity-sensitive for speech sound stimuli presented in rapid succession.