He has continued this interest throughout his career with a focus on using brain imaging and brain stimulation to understand depression and devise new treatments.
He was one of the first to use functional brain imaging during normal emotions as well as in depression and mania. He has grown the science of brain stimulation, both in terms of how the treatments work in the brain, and in critically evaluating their therapeutic applications, especially in treating depression. He may be unique in being the only living neuroscientist with two FDA approved treatments that stem from their work. Transcranial magnetic stimulation (TMS) was FDA approved for treating depression in October, 2008. In June 1998 at MUSC, he also pioneered another new treatment for resistant depression, vagus nerve stimulation (VNS). This was FDA approved in 2006.