Anxiety disorders such as post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD) affect a large number of individuals with a significant portion of patients failing to improve with current treatments. The purpose of this study is to understand the brain mechanisms that produce fear and anxiety in humans. To accomplish this goal, we will measure the brain activity along with the heart rate and skin perspiration of patients while they are completing tasks on a computer. Some of the tasks will also use a virtual reality headset and transport the patient in a video game-like environment. These tasks will expose the participants to various levels of fear-provoking images. Participants with responsive neurostimulation (RNS) implants will be enrolled under Pro00117931 at Duke, but their results for fear and anxiety tasks will be reported under NCT05120635.