Did I Do That? Abnormal Predictive Processes in Schizophrenia When Button Pressing to Deliver a Tone

• Published in: Schizophrenia bulletin Vol. 40; no. 4; pp. 804 - 812
• Main Authors: FORD, Judith M, PALZES, Vanessa A, ROACH, Brian J, MATHALON, Daniel H
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-07-2014
• Subjects: Adult; Adult and adolescent clinical studies; Auditory Cortex - physiopathology; Biological and medical sciences; Case-Control Studies; Contingent Negative Variation - physiology; Evoked Potentials, Auditory - physiology; Female; Humans; Male; Medical sciences; Middle Aged; Motor Activity - physiology; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Psychotic Disorders - physiopathology; Psychotic Disorders - psychology; Regular; Schizophrenia; Schizophrenia - physiopathology; Schizophrenic Psychology; Young Adult; predictive coding; Central nervous system; Prediction; Electrophysiology; Schizophrenia; Cognition; corollary discharge; Encephalon; Psychosis; ERPs; Coding; efference copy; Event evoked potential
• ISSN: 0586-7614; 1745-1701
• DOI: 10.1093/schbul/sbt072

Motor actions are preceded by an efference copy of the motor command, resulting in a corollary discharge of the expected sensation in sensory cortex. These mechanisms allow animals to predict sensations, suppress responses to self-generated sensations, and thereby process sensations efficiently and economically. During talking, patients with schizophrenia show less evidence of pretalking activity and less suppression of the speech sound, consistent with dysfunction of efference copy and corollary discharge, respectively. We asked if patterns seen in talking would generalize to pressing a button to hear a tone, a paradigm translatable to less vocal animals. In 26 patients [23 schizophrenia, 3 schizoaffective (SZ)] and 22 healthy controls (HC), suppression of the N1 component of the auditory event-related potential was estimated by comparing N1 to tones delivered by button presses and N1 to those tones played back. The lateralized readiness potential (LRP) associated with the motor plan preceding presses to deliver tones was estimated by comparing right and left hemispheres' neural activity. The relationship between N1 suppression and LRP amplitude was assessed. LRP preceding button presses to deliver tones was larger in HC than SZ, as was N1 suppression. LRP amplitude and N1 suppression were correlated in both groups, suggesting stronger efference copies are associated with stronger corollary discharges. SZ have reduced N1 suppression, reflecting corollary discharge action, and smaller LRPs preceding button presses to deliver tones, reflecting the efference copy of the motor plan. Effects seen during vocalization largely extend to other motor acts more translatable to lab animals.