Embodied Predictions, Agency, and Psychosis

Area of Science:

• Cognitive Neuroscience
• Computational Psychiatry
• Neuroscience of Psychosis

Background:

• Psychotic symptoms like hallucinations and delusions represent significant deviations from shared reality.
• In schizophrenia, these symptoms are often linked to an abnormal sense of agency, manifesting as passivity experiences.
• Current models explain psychosis via the brain's generative model, involving prediction errors and prior beliefs.

Purpose of the Study:

• To reconcile conflicting evidence on agency (enhanced vs. diminished) in schizophrenia.
• To propose a novel dual-generative model explaining psychotic symptoms and agency disturbances.
• To investigate the interplay between ego-centric and allo-centric predictive processing in psychosis.

Main Methods:

• Theoretical modeling integrating computational neuroscience principles.
• Review and synthesis of existing empirical evidence on agency and psychosis.
• Hypothesizing the roles of corollary discharge and predictive coding in schizophrenia.

Main Results:

• Evidence suggests both enhanced and diminished agency experiences in schizophrenia, posing a theoretical challenge.
• A dual-model proposes separate ego-centric (feeling of agency) and allo-centric (judgement of agency) systems.
• Schizophrenia may involve impaired self-monitoring (corollary discharge failure) and compensatory reliance on external cues.

Conclusions:

• A failure in ego-centric corollary discharge may lead to a lack of 'feeling of agency' in schizophrenia.
• Compensatory enhancement of allo-centric priors could explain hallucinations and delusions of control.
• This dual-model offers a framework for understanding varied agency experiences and psychotic symptoms in schizophrenia.