Functional neuroanatomy of verbal self-monitoring

The neural correlates of verbal self-monitoring were examined by measuring the response to alternations in auditory verbal feedback while subjects read aloud. Six normal subjects were studied with PET, using (H2O)-O-15 as a tracer of regional CBF. There was no difference between the temporal cortical response to reading aloud (and hearing one's own speech) and reading silently while hearing the words spoken by someone else. Distortion of subjects' speech (by pitch elevation) while they read aloud led to a bilateral activation of lateral temporal cortex, with a greater response on the right side than the left. A similar pattern of activation was evident when subjects read aloud, but the words they heard were spoken by someone else. These data suggest that (i) self- and externally generated speech are processed in similar regions of temporal cortex, and (ii) the monitoring of self-generated speech involves the temporal cortex bilaterally, in areas associated with the processing of speech which has been generated externally.