Deep brain stimulation (DBS) is a surgical

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 treatment involving the implantation of a medical device called a brain pacemaker

Brain pacemaker

"Brain pacemakers" are used to treat people who suffer from epilepsy, Parkinson's disease, major depression and other diseases. The pacemaker is a medical device that is implanted into the brain to send electrical signals into the tissue. Depending on the area of the brain that is targeted, the...

, which sends electrical impulses to specific parts of the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. DBS in select brain regions has provided remarkable therapeutic benefits for otherwise treatment-resistant movement and affective disorders such as chronic pain

Chronic pain

Chronic pain has several different meanings in medicine. Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time from onset; the two most commonly used markers being 3 months and 6 months since the initiation of pain, though some theorists and...

, Parkinson's disease

Parkinson's disease

Parkinson's disease is a degenerative disorder of the central nervous system...

, tremor

Tremor

A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the...

 and dystonia

Dystonia

Dystonia is a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning or reaction to...

. Despite the long history of DBS, its underlying principles and mechanisms are still not clear.