Differing functional mechanisms underlie cognitive control deficits in psychotic spectrum disorders

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Cognitive control deficits are common in psychotic spectrum disorders (PSD).
• The functional neuroimaging underpinnings, particularly in the lateral prefrontal cortex (PFC), remain debated.
• Previous research often suggests hypofrontality and greater proactive than reactive control deficits.

Purpose of the Study:

• To investigate the hemodynamic response during cognitive control tasks in patients with PSD.
• To examine the relationship between neural activity, clinical symptoms, and diagnostic classifications.
• To clarify the nature of PFC abnormalities in PSD.

Main Methods:

• 154 patients with PSD and 65 healthy controls performed the AX continuous performance task (AX-CPT).
• Rapid (460 ms) functional neuroimaging was used to measure brain activity.
• Participants underwent full clinical characterization.

Main Results:

• Patients with PSD exhibited generalized cognitive deficits (slower, less accurate) in both proactive and reactive control.
• A delayed/prolonged neural response in the left dorsolateral PFC, sensorimotor cortex, and superior parietal lobe was observed during proactive control in PSD patients.
• These proactive hemodynamic abnormalities were better explained by negative symptoms than by positive symptoms or DSM-IV-TR diagnoses.
• True hypoactivity was observed in the ventrolateral PFC during reactive control, independent of clinical symptoms or diagnoses.

Conclusions:

• The AX-CPT may have limited utility for neuroimaging appraisal of cognitive control in the full spectrum of PSD.
• Reported lateral PFC "hypoactivity" during proactive control might represent a delayed/prolonged neural response, relevant for rehabilitation.
• Negative symptoms may offer a better explanation for certain behavioral and hemodynamic abnormalities in PSD compared to traditional diagnostic categories.