Cerebral response to 'voiceness': a functional magnetic resonance imaging study.

We evaluated the response of the voice-selective areas of the auditory cortex to sound 'voiceness', that is, the degree to which an auditory stimulus resembles human voice. Normal participants were scanned using event-related functional magnetic resonance imaging while passively listening to stimuli drawn from a 'voiceness' continuum generated via auditory morphing between sounds of voice and sounds of musical instruments. The voice-selective areas of the left and right superior temporal sulcus did not show the expected relation between 'voiceness' and size effect. Instead, superior temporal sulcus activity seemed mostly driven by sound naturalness, with largest activity differences observed for the intermediate, voice-instrument hybrid stimuli.