Abstract
Background: Sounds often occur as a result of our own movements—we hear ourselves talk, we hear our footsteps when we walk, we hear our fingertips on the keyboard. The fact that self-initiated sounds typically evoke a smaller auditory-evoked potential than physically-identical, externally-generated sounds suggests that we predict and suppress sounds generated by our own actions. A prominent model of schizophrenia argues that many characteristic features of the disorder (eg, passivity experiences) arise from abnormalities predicting the sensory consequences of self-generated actions. Schizophrenia patients show subnormal levels of electrophysiological self-suppression, suggestive of an abnormality in sensory prediction; however, the nature of this abnormality remains unclear. Methods: This talk will introduce a series of novel electrophysiological paradigms, which have been developed in an attempt to better elucidate the nature of auditory self-suppression deficits in schizophrenia. These paradigms are innovative in that they enable different facets of the auditory prediction to be disentangled, such as the expected sensory and temporal properties of the sound, and the established strength of the action-sound association. Results: Preliminary results suggest that while healthy individuals make detailed predictions about the expected sensory and temporal properties of sounds resulting from self-initiated movements, schizophrenia patients (and nonclinical high schizotypes) show characteristic abnormalities in these sensory predictions, suggestive of a consistent neural abnormality in self-suppression. Conclusion: Identifying the parameters under which schizophrenia patients do and do not suppress the electrophysiological consequences of self-generated sounds will shed light on the mechanistic basis of self-suppression abnormalities (eg, whether they are due to corollary discharge abnormalities or a more general deficit in prediction) and provide insight into the etiology of the characteristic symptoms of this disorder, such as passivity experiences and auditory hallucinations.