Deep-Brain Stimulation for Basal Ganglia Disorders

Abstract

The realization that medications used to treat movement disorders and psychiatric conditions of basal ganglia origin have significant shortcomings, as well as advances in the understanding of the functional organization of the brain, has led to a renaissance in functional neurosurgery, and particularly the use of deep brain stimulation (DBS). Movement disorders are now routinely being treated with DBS of 'motor' portions of the basal ganglia output nuclei, specifically the subthalamic nucleus and the internal pallidal segment. These procedures are highly effective and generally safe. Use of DBS is also being explored in the treatment of neuropsychiatric disorders, with targeting of the 'limbic' basal ganglia-thalamocortical circuitry. The results of these procedures are also encouraging, but many unanswered questions remain in this emerging field. This review summarizes the scientific rationale and practical aspects of using DBS for neurologic and neuropsychiatric disorders.

Figure 1

‘Motor’ and ‘limbic’ cortex-basal ganglia-thalamocortical circuits. The targets of current DBS treatments are labeled with asterisks (*), and movement disorders and neuropsychiatric disorders caused by dysfunction of these circuits are listed below the circuit diagrams. Abbreviations: ACA, anterior cingulate area; CMA, cingulate motor area; M1, primary motor cortex; MD, mediodorsal nucleus of thalamus; MOFC, medial orbitofrontal cortex; PMC, premotor cortex; SMA, supplementary motor area; VApc, ventral anterior nucleus of thalamus, pars parvocellularis; VAmc, ventral anterior nucleus of thalamus, pars magnocellularis; VLm, ventrolateral nucleus of thalamus, pars medialis; VLo, ventrolateral nucleus of thalamus, pars oralis. See text for other abbreviations. Modified from a figure in ref. [251], used with permission.

Figure 2

DBS targets for treatment of severe TRD. A. Target in the sugbgenual cortical area 25, as identified in depression patients with induction of sadness accompanying the recollection of a sad memory, using PET to measure cerebral blood flow changes. Areas in red represent a significant increase in blood flow, while areas in blue show decreased blood flow. B. MRI image showing the DBS lead position in a TRD patient with DBS of the anterior limb of the internal capsule/ventral striatum target. C. Sagittal view of fluoro-deoxyglucose positron emission tomography (FDG-PET) imaging of the metabolic effects of DBS in the lateral habenula for treatment of TRD. The position of the electrode tip position is marked in green. This figure is a compilation of previously published images. The image under A. was published in ref. [237], the one under B. by ref. [247], and the image under C. stems from ref. [245]. All images were used with permission.