Basal Ganglia Motor Circuit is Target Site for Surgical Intervention
Farooq I. Khan, MD,
Robert Chen, MBBChir, MSc, FRCPC
Movement Disorders Centre,
Division of Neurology,
Toronto Western Hospital,
University of Toronto
Parkinson's Disease (PD) was first described by James Parkinson in 1817, and is a neurodegenerative disease that is characterized by tremor, bradykinesia, rigidity and postural instability. It results from the degeneration of the dopaminergic neurons in the substantia nigra (pars compacta) causing alterations in the basal ganglia circuitry; this circuitry is responsible for modulating and facilitating motor function through the cerebral cortex. The evolution of the treatment for PD has relied on both pharmacological and surgical approaches, arguably the most important of which was the discovery of levodopa in the early 1960s. Since then a number of other pharmacological agents such as monoamine oxidase (MAO) inhibitors, catechol-O-methyltransferase (COMT) inhibitors, and dopamine agonists, have played a vital role in the amelioration of disability arising from this disease. Unfortunately, long term pharmacotherapy, especially with levodopa, has caused problems of its own, namely the occurrence of fluctuation and dyskinesia. For these and other reasons that will be discussed, surgery has offered a ray of hope to combat this eventually crippling disease.