Deep Brain Stimulation in Clinical Practice and in Animal Models

Deep brain stimulation (DBS) has dramatically changed the landscape of neurosurgery. Overall, the technique consists of the delivery of current into the brain parenchyma through implanted electrodes (Figure 1). It is estimated that 60,000 patients worldwide have received DBS, with the rate of accrual currently approaching 8,000 to 10,000 new patients a year. Although electrical stimulation has been used for more than 50 years to treat psychiatric disorders and pain, the technique as conducted today reemerged some 25 years ago, in the field of movement disorders. The striking clinical effects of DBS in these conditions and the similarities in outcome between stimulation and lesions soon prompted the investigation of the technique for various diseases previously treated by functional neurosurgeons. Equally important for the development of the therapy were imaging and electrophysiological studies. Because DBS modulates local neuronal activity and influences regions at a distance from the stimulated site, dysfunctional anatomic circuits and structures have been regarded as potential targets. Animal research has provided the rationale for the use of DBS in some applications of the therapy, although most experimental studies have been conducted to explore potential mechanisms for the effects of stimulation.