Mental inflexibility is a hallmark of neuropsychiatric disorders, including addiction, depression, obsessive compulsive disorder and Parkinson’s Disorder. For instance, it is often easier to stay stuck exploiting patterns of behavior than to flexibly explore and consider other potentially more rewarding options. Cognitive flexibility, as captured by the tradeoff between exploration and exploitation, has been a rich area of both computational and neuroscientific research and is a growing area of interest in computational psychiatry. We are studying neural mechanisms underlying flexibility and it’s potential modulation with brain stimulation.