Deep Brain Stimulation (DBS)

BRAIN AREA: Cerebrum – Basal Ganglia – Subthalamic Nucleus

See Image 6

Deep brain stimulation (DBS) involves electrical stimulation of key parts of the brain to treat a range of medical conditions including Parkinson's disease, parkinsonism, dystonia, epilepsy, Obsessive Compulsive Disorder, depression, chronic pain, Tourette syndrome and schizophrenia.

Deep brain stimulation blocks electrical signals to or from targeted areas in the brain. Where DBS is applied to the subthalamic nucleus, it has a similar effect to lesioning that nucleus without the abnormal involuntary movements (hemiballismus) that can result from damage to the area.

The success of electrically stimulating the subthalamic nucleus as a treatment for Parkinson's disease over the past 25 years has confirmed the role of the subthalamic nucleus in the excitation of basal ganglia nuclei, seen in Image 5 (globus pallidus internus and pars reticulata of the substantia nigra), that inhibit unwanted movements, and also assisted our understanding of cognitive and limbic functions of the subthalamic nucleus.

DBS is also used for certain cases of Obsessive Compulsive Disorder where the limbic and associative (cognitive) areas of the subthalamic nucleus are targeted. This level of stimulation has been shown to decrease the need for repeated movements and checking (patterns of unresolved obsession and ritual, eg. 'Did I leave the oven on?'), by increasing impulsiveness in order to restore more normal functioning and override unnecessary repetition.

References & further reading

Temel, Y., Blokland, A., & Steinbusch, H. W. M. (2005). The functional role of the subthalamic nucleus in cognitive and limbic circuits. Progress in Neurobiology, 76(6), 393–413.

Voon, V., Droux, F., Morris, L., Chabardes, S., Bougerol, T., David, O., Krack, P., & Polosan, M. (2017). Decisional impulsivity and the associative-limbic subthalamic nucleus in obsessive-compulsive disorder: Stimulation and connectivity. Brain, 140(2), 442–546.