To evaluate the utility of a paced motor activation task as a longitudinal probe of FSC function, we conducted fMRI scans of 10 subjects with bipolar I disorder when euthymic. We compared activation patterns to the same subjects who had been previously scanned during an episode of depression.
The paced motor task resulted in activation in the bilateral striatum which was consistent across mood states as well as greater activation among the subjects when euthymic in the right anterior cingulate and medial frontal gyrus.
The study sample was small (10 subjects) which limits generalizability of findings.
To our knowledge, this is the first longitudinal study of bipolar illness utilizing a paced motor task. These findings suggest that a paced motor task is useful as a longitudinal probe of both state and trait function in bipolar disorder. Further, this study provides preliminary evidence that striatal functional abnormalities may represent a trait characteristic.