Did I do that? Abnormal predictive processes in schizophrenia when button pressing to deliver a tone

Area of Science:

• Neuroscience
• Cognitive Science
• Psychiatry

Background:

• Motor commands generate an efference copy, predicting sensations via corollary discharge for efficient sensory processing.
• Schizophrenia is associated with deficits in these predictive mechanisms, observed during vocalization.

Purpose of the Study:

• To investigate if efference copy and corollary discharge deficits in schizophrenia generalize from vocalization to non-vocal motor tasks.
• To examine the relationship between motor planning (LRP) and sensory suppression (N1) in schizophrenia patients and healthy controls.

Main Methods:

• Compared auditory N1 event-related potential suppression to self-generated tones (button press vs. playback) in 23 schizophrenia (SZ) and 3 schizoaffective (SZ) patients versus 22 healthy controls (HC).
• Assessed the lateralized readiness potential (LRP) preceding button presses to measure motor planning.
• Correlated LRP amplitude with N1 suppression to assess the efference copy-corollary discharge link.

Main Results:

• Healthy controls showed larger LRPs and greater N1 suppression than schizophrenia patients.
• A positive correlation between LRP amplitude and N1 suppression was observed in both groups.
• Schizophrenia patients exhibited reduced N1 suppression and smaller LRPs, indicating impaired corollary discharge and efference copy.

Conclusions:

• Deficits in efference copy and corollary discharge observed in schizophrenia during vocalization extend to non-vocal motor actions.
• These findings highlight a fundamental sensory processing dysfunction in schizophrenia, relevant for developing animal models and therapeutic strategies.