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Abstract:
Abstract: Several behavioral and brain imaging studies have
demonstrated a significant interaction between speech reception and
speech production. In this study, auditory cortical responses to
speech during self-production and feedback alteration were
examined. Magnetic field recordings were obtained from both
hemispheres of subjects who spoke while hearing controlled versions
of their speech feedback via earphones. These responses were
compared to magnetic field recordings made while subjects listened
to a tape recording of their production. The amplitude of the tape
playback was adjusted to be equal to the amplitude of produced
speech. Successful recordings of evoked responses to both
self-produced and tape-recorded speech were obtained free of
movement-related artifacts. We observed that responses to
self-produced speech was weaker when compared to responses to
tape-recorded speech. Responses to tones were also weaker during
speech production when compared with responses to tones in the
presence of tape-recorded speech. However, responses to gated noise
stimuli did not differ between presentations during self-produced
and tape-recorded speech playback. These data suggest that during
speech production auditory cortex (1) attenuates its sensitivity
and (2) modulates its activity as a function of the expected
acoustic feedback.
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