Relationship of imprecise corollary discharge in schizophrenia to auditory hallucinations.

Context: A forward model of intended thoughts and actions prepares sensory cortex for sensations that are a consequence of those actions. Imprecision of the corollary discharge in schizophrenia may contribute to the misperception of inner experiences and thoughts as "voices" or auditory hallucinations.

Objectives: To assess the precision of the forward model in schizophrenia using the N100 component of the auditory event-related potential to speech that is altered or unaltered, in real time, as it is being spoken.

Magnetoencephalographic evidence for a precise forward model in speech production.

Electroencephalography and magnetoencephalography studies have shown that auditory cortical responses to self-produced speech are attenuated when compared with responses to tape-recorded speech, but that this attenuation disappears if auditory feedback is altered. These results suggest that auditory feedback during speaking is processed by comparing the feedback with its internal prediction. The present study used magnetoencephalography to investigate the precision of this matching process.

Fine-tuning of auditory cortex during speech production.

The cortex suppresses sensory information when it is the result of a self-produced motor act, including the motor act of speaking. The specificity of the auditory cortical suppression to self-produced speech, a prediction derived from the posited operation of a precise forward model system, has not been established. We examined the auditory N100 component of the event-related brain potential elicited during speech production.