Deep Brain Stimulator (DBS) - A device consisting of an electrode and a battery-powered generator which is used to control symptoms of various kinds of movement disorders. The electrode is implanted by stereotactic surgery on one or, more commonly, both sides of the brain. The generators are implanted beneath the skin on the front of the chest.

Dyskinesia - Abnormal movements often seen in patients with Parkinson's disease with a long history of L-DOPA use. Movements are generally present when "on" medication and look kind of like a squirmy three-year old.

Globus Pallidus - A large nucleus within the brain (Fig. 1). The target for pallidotomy surgery for Parkinson's disease or dystonia. Sometimes also used for implantation of DBS for treatment of Parkinson's disease or dystonia.

Neuron - Commonly called a "nerve cell". One of the two main types of cells making up the central nervous system (brain and spinal cord). The other type is called "glia". Neurons carry out most of the functions which we commonly associate with the brain through their interconnections and internal processing capability.

Nucleus - A collection of neurons in the central nervous system located somewhere other than the surface of the brain, i.e. deep within the brain itself. Each neuron itself has within it a structure called a nucleus (as do all other human cells except red blood cells), but this is something completely different. Central nervous system nuclei tend to be specialized to carry a small number of related functions.

Pallidotomy - A stereotactic operation done on the globus pallidus designed to destroy a small patch of hyperactive cells. Can improve many of the symptoms of Parkinson's disease and perhaps dystonia.

Stereotactic Surgery - A type of operation in which a metal frame (Fig. 3) is attached to the skull and used to pass guided probes through "silent" portions of the brain to reach targets (like nuclei) deep within the brain.

Subthalamic Nucleus - A nucleus (Fig. 1) located beneath the thalamus. Probably the best target for DBS placement for treatment of symptoms of Parkinson's disease.

Thalamotomy - A stereotactic operation done on the thalamus in which a small area which appears to be generating tremor is destroyed. Sometimes used for treatment of essential tremor and occasionally for tremor-predominant Parkinson's disease.

Thalamus - A group of nuclei which are collected together (Fig. 1). Often considered to perform a sort of gating function between the cerebral cortex and lower portions of the central nervous system. The VIM nucleus of the thalamus is usually the target in DBS or thalamotomy surgery for essential tremor.