Absence of activation in frontal structures during psychological testing of chronic schizophrenics.

The distribution of activity in the dominant hemisphere was measured with the regional cerebral blood flow (rCBF) technique in 27 chronic schizophrenics and 15 non-schizophrenic control subjects (alcoholics) at rest and during phychological testing. In the non-schizophrenics, an increase of rCBF was observed during the test in frontal regions. In the chronic schizophrenics, on the other hand, no or only a very limited increase was recorded. In postcentral structures the flow response during the testing was, by and large, equal in the psychotics and the controls. The findings support the hypothesis advanced previously by the authors that in chronic schizophrenia there is defective transmission in the mediothalamic frontocortical projection bundle. This defect also appears responsible for the abnormally low resting flow (activity) in the dominant hemisphere in chronic schizophrenia which we have described previously.