Project Summary

Michael P. Caligiuri, Ph.D. (Independent Investigator 2002) of Veterans Medical Research Foundation (VA), is studying specific regions of the motor system, including the basal ganglia and cortex, using functional magnetic resonance imaging (fMRI) in order to identify similarities and differences in brain function during the depressed and manic phases of bipolar disorder.  The periodic shifting of motor function in the various phases of bipolar disorder, between hyperactivity (or agitation in mania) and hypoactivity (or motor retardation in depression), suggests that, as with affect, the neural mechanisms underlying motor behavior are also unstable.  He plans to examine patterns of brain activation within the motor systems to gain insight into the neurobiology of fluctuating affect.  He will use fMRI to study brain function during two tasks that are sensitive to fluctuating motor function: reaction time and scaling movement velocity.  Failure to scale movement velocity is a hallmark sign in Parkinson's Disease and he has pilot data showing this to be a problem in many patients with bipolar disorder as well. There is good reason to believe that the motor retardation (generalized slowness) seen in the depressive phase of bipolar illness and parkinsonian bradykinesia (reduced speed of movement) may share a common abnormality thought to reside in the basal ganglia.  The potential benefits for clinical application and future basic research are significant.  Dr. Caligiuri may be able to use results from the fMRI assessment of motor function to predict conversion from unipolar to bipolar depression, whether or not an individual will be responsive to treatment, and provide a firm phenotype with which geneticists can work.

Program Area: MOOD DISORDERS\Bipolar

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