ABSTRACT
INTRODUCTIONThe complex neural circuitry involved in Parkinson’s disease (PD) has relevance for a number of neurologic and psychiatric deep brain stimulation (DBS) applications and is thus reviewed in detail in this chapter. PD results from loss of the dopaminergic cells in the substantia nigra pars compacta (SNc). These cells project to the striatum, and striatal dopamine depletion causes the motor symptoms of the disease: bradykinesia, resting tremor and muscle rigidity. Dopamine loss in the striatum and basal ganglia leads to abnormal discharge patterns in the circuitry that controls motor function in the brain, ultimately resulting in abnormal activation of primary cortical motor neurons and concomitant abnormalities of movement. Thus, although the pathologic hallmark of PD is loss of dopaminergic neurons in the SNc, the clinical symptoms of the disease are due to pathologic disturbances in the activity of neurons in the motor control circuits of the brain.
