Corollary discharge function in healthy controls: evidence about
self-speech and external speech processing.
As we speak, corollary discharge mechanisms suppress the auditory
conscious perception of the self-generated voice in healthy subjects.
This suppression has been associated with the attenuation of the
auditory N1 component. To analyze this corollary discharge phenomenon
(agency and ownership), we registered the Event-Related Potentials of
forty-two healthy subjects. The N1 and P2 components were elicited by
spoken vowels (talk condition; agency), by played-back vowels recorded
with their own voice (listen-self condition; ownership), and by
played-back vowels recorded with an external voice (listen-other
condition). The N1 amplitude elicited by the talk condition was smaller
compared to the listen-self and listen-other conditions. There were no
amplitude differences in N1 between listen-self and listen-other
conditions. The P2 component did not show differences between
conditions. Additionally, a peak latency analysis of N1 and P2
components between the three conditions showed no differences. These
findings corroborate previous results showing that the corollary
discharge mechanisms dampen sensory responses to self-generated speech
(agency experience), and provide new neurophysiological evidence about
the similarities in the processing of played-back vowels with our own
voice (ownership experience) and with an external voice.