Deep brain stimulation of the medial forebrain bundle in depression

Deep brain stimulation (DBS) targeted to several brain areas has shown considerable promise in treating treatment-resistant depression with 40-60% of patients improving after one year of treatment. Because in virtually all included patients white matter was stimulated, several research groups started imaging white matter tracts to investigate whether specific tracts were associated with response. One of the identified tracts was the superolateral branch of the medial forebrain bundle (slMFB). This talk will discuss the evolution from targeting nuclei around the striatum using structural MRI to targeting the slMFB using diffusion weighed imaging (DWI). After a brief overview of the literature on slMFB DBS, the tractography results from patients with DBS targeted to the internal capsule will be shown. Distance to the medial forebrain bundle was associated with the magnitude of symptom reduction in patients with obsessive-compulsive disorder (n=12) as well as with major depression (n=14). These results inspired to set up a recently started clinical trial, in which we treat patients with treatment-resistant depression. The target is the slMFB for which we use DWI in the surgery planning. The first patients have now been enrolled, of which the first experiences will be shared. Keywords: deep brain stimulation, treatment-resistant depression, tractography, clinical trial