Differential processing of metacognitive evaluation and the neural circuitry of the self and others in schizophrenia: a pilot study.

BACKGROUND: Impaired awareness of the self and others (i.e., metacognitive evaluations) are seen in schizophrenia. We compared patterns of activation in schizophrenia (SZ) and nonclinical subjects during a functional magnetic resonance imaging (fMRI) task of metacognitive evaluations that has been demonstrated to engage the neural circuitry of the self in healthy subjects.
METHODS: Eleven SZ subjects (7 males, mean age 26.6+/-8) and 10 healthy control subjects (4 males, mean age 29.6+/-8.4) were enrolled. Participants completed two runs of a metacognitive evaluation task (self vs. other vs. word meaning). fMRI data was obtained using a full body Bruker MedSped 4.0Tesla system. Group contrasts were performed using an uncorrected p<0.005 with a 50voxel extent threshold.
RESULTS: We observed a significant hypoactivation in the left superior temporal sulcus (STS) during metacognitive evaluations of others (OE) vs. semantic positivity evaluations (SPE) and a trend toward significant hypoactivation in the OE vs. self evaluations (SE) in the SZ group. Significant hypoactivation was also seen in the right inferior temporal gyrus (ITG) in the OE vs. SE contrasts in the SZ group. A trendworthy hypoactivation was seen in the SZ group in the right middle frontal gyrus and pole of the left STS during OE vs. SPE and SE contrasts respectively.
CONCLUSIONS: These results extend previous findings of impaired metacognitive evaluative processes in schizophrenia to aberrations of the neural circuitry implicated in self/other awareness among SZ patients. Greater understanding of the neural basis of deficits of self/other awareness in early schizophrenia may contribute to improvements in the identification and treatment of individuals at risk for the illness. 2009 Elsevier B.V. All rights reserved.