Neurophysiological Markers of the “Self” in Psychosis: Insights from the SUCEDE Project:
As part of the ongoing dissemination of the SUCEDE project, we are sharing a synthesis of our current findings focused on the cerebral substrates of agency recognition and its alteration across the psychotic spectrum.
- The N1 Suppression Paradigm: Action Monitoring
Our research is grounded in the corollary discharge mechanism. Under normal physiological conditions, the brain generates an internal signal when initiating a motor act (such as speech). This signal pre-activates the auditory cortex, resulting in an attenuation of the N1 event-related potential (ERP) when we hear our own voice in real-time. - Transdiagnostic Findings and Clinical Correlation
Through electroencephalography (EEG) analysis, we have identified distinct patterns that allow us to map dysfunction in “self” recognition:
- Deficits in Schizophrenia: Patients exhibit significantly reduced N1 suppression. This finding is not merely an isolated biomarker; it correlates robustly with the severity of anomalous self-experiences and positive symptomatology.
- Bipolar Spectrum: Data suggests an intermediate phenotype. While these patients demonstrate greater suppression capacity than the schizophrenia group, they do not reach the efficiency levels observed in healthy controls.
- Dissociating Agency from Ownership
A critical point of our current discussion is the distinction between two fundamental constructs:
- Ownership: The recognition that a stimulus belongs to oneself, linked to the early N1 component.
- Agency: The attribution of authorship of the act, reflected in later components such as the P2.
- Multimodal Integration: Neurophysiology and Neuroimaging
To further explore the underlying pathophysiology, we are integrating EEG source analysis with Diffusion Tensor Imaging (DTI). The objective is to determine if structural connectivity alterations in the arcuate fasciculus—which connects language production and perception areas—serve as the anatomical substrate predicting the sensory suppression failures observed clinically. - Conclusions and Future Directions:
With a growing sample size currently exceeding 110 participants (including both controls and patients), the project aims to consolidate these biomarkers to improve diagnostic precision and better understand the fragmentation of the “self” in psychosis.
Access the Audiovisual Document: https://youtu.be/MB5cFJMVYHY