Neuroimaging Provides Clearer Picture of Brain Dysfunction in Schizophrenia

By: Megan Rauscher

NEW YORK (Reuters Health) Aug 04 – In schizophrenic patients, there are regions within the prefrontal cortex that are
hypoactive and others that are hyperactive, functional neuroimaging data show.

“The hyperactive areas may be compensating for the hypoactive areas,” Dr. Michael J. Minzenberg, of the department
of psychiatry, University of California, Davis School of Medicine, Sacramento, noted in an email to Reuters Health.

To better understand prefrontal cortex dysfunction in schizophrenia, Dr. Minzenberg and colleagues performed a
quantitative meta-analysis of 41 peer-reviewed studies that investigated executive function in schizophrenic patients
and healthy controls using functional magnetic resonance imaging.

They report, in the Archives of General Psychiatry for August, that healthy adults and schizophrenic patients activate a qualitatively similar neural network during executive task performance, “consistent with the engagement of a general purpose cognitive control network.” Predominant areas of activation include the dorsolateral prefrontal cortex,
ventrolateral prefrontal cortex, and anterior cingulate cortex and the thalamus.

However, patients with schizophrenia also show reduced activation in the left dorsolateral prefrontal cortex,
rostral/dorsal anterior cingulate cortex, left thalamus and inferior/posterior cortical areas, whereas increased activity
was seen in other prefrontal cortex areas.

“The present results taken together strongly argue against a simple hypofrontality versus hyperfrontality account of the altered function of the frontal cortex in schizophrenia,” the researchers write.

“The main clinical implications,” Dr. Minzenberg added, “are that there might be relatively few pathological processes
that may give rise to the diversity of PFC dysfunction in schizophrenia, and that the cognitive control network that we
propose may serve as a major, overarching treatment target.”

Arch Gen Psychiatry 2009;66:811-822.

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