Prof. Robert JECH, MD, PhD, Center for interventional therapy of movement disorders, Department of Neurology, Charles University, 1st Faculty of Medicine and General University Hospital in Prague (Kateřinská 30, 120 00 Praha, Czech Republic)

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus interna (GPi) has become an important method for the treatment of Parkinson´s disease and other movement disorders. While the STN DBS has remarkable effect on motor function causing improved rigidity, movement acceleration and tremor suppression, the GPi DBS has direct anti-dyskinetic effect frequently used in treatment of generalized dystonic syndromes. Though the positive DBS effects on the motor system are beyond doubt their mechanisms are not fully understood. In addition, these structures have rich connections with a number of non-motor circuits, which is especially in the STN DBS the reason for higher risks of possible adverse reactions. Despite its tiny dimension the STN has a complex spatial organization with the motor portion situated dorsolaterally, cognitive – centrally and the limbic – ventromedially whose boundaries largely overlap. While the cognitive domain carries the risk of worsening of executive deficit and loss of control on impulsive and inhibitive behavior, in the limbic domain, there is a risk of apathy, accentuated sensitivity to negative stimuli and the worsening of depressive syndrome associated with chronic fatigue, anxiety and obesity. Clinical improvement and side effects of the STN/GPi DBS critically depend on the position of the active electrode within each nucleus in a manner that reflects the functional organization.