Deep brain stimulation for enhancement of learning and memory.

Deep brain stimulation (DBS) has emerged as a powerful technique to treat a host of neurological and neuropsychiatric disorders from Parkinson's disease and dystonia, to depression, and obsessive compulsive disorder (Benabid et al., 1987; Lang and Lozano, 1998; Davis et al., 1997; Vidailhet et al., 2005; Mayberg et al., 2005; Nuttin et al., 1999). More recently, results suggest that DBS can enhance memory for facts and events that are dependent on the medial temporal lobe (MTL), thus raising the possibility for DBS to be used as a treatment for MTL- related neurological disorders (e.g. Alzheimer's disease, temporal lobe epilepsy, and MTL injuries). In the following review, we summarize key results that show the ability of DBS or cortical surface stimulation to enhance memory. We also discuss current knowledge regarding the temporal specificity, underlying neurophysiological mechanisms of action, and generalization of stimulation's effects on memory. Throughout our discussion, we also propose several future directions that will provide the necessary insight into if and how DBS could be used as a therapeutic treatment for memory disorders.