Slow potential correlates of frontal function, psychosis, and negative symptoms.

The contingent negative variation (CNV) was used to study cortical activation in frontal and central areas in psychotic and nonpsychotic patients. Psychotic patients showed a higher frontal relative to central CNV amplitude than nonpsychotic patients, a finding that was correlated with performance on a test of frontal function. Negative symptom ratings (physical anhedonia and social closeness) were correlated with relatively low frontal versus central CNV amplitude, but only in psychotic patients.