PILOT STUDY OF IMPACT OF EXERCISE ON HIPPOCAMPAL BEHAVIOR IN ANXIETY DISORDER PATIENTS
Principal Investigator: H. Blair Simpson, M.D., Ph.D.; Co-Investigator, Richard P. Sloan, Ph.D.
This is a pilot study to explore whether a protocol of High Intensity Interval Training (HIIT) aerobic exercise can improve anxiety measures and/or performance on hippocampal dependent behaviors. HIIT is a form of interval training that alternates short periods of high effort exercise with less intense recovery periods. Subjects in this study will undertake a 6-week protocol of HIIT exercise, consisting of four 15-minute sessions per week, performed at home on a portable stepper device provided by the study. Outcome measures for this study will be performance on two hippocampus-dependent behaviors and responses to mood and anxiety questionnaires. The hippocampus is a brain structure that is involved in learning and memory, and is one of the two sites of adult neurogenesis, the process of generating of new neurons from stem cells in the adult mammalian brain. Adult neurogenesis has been linked to anxiety in animal models, and may represent a new target for the treatment of anxiety disorders if it can also be linked to anxiety in humans. It is not possible to assess neurogenesis directly in the living human brain, so we propose to measure it indirectly via tests of hippocampal-dependent behaviors. The tests we will use consist of a picture-based memory task and a location memory task, and will be carried out on a computer. Eligible subjects will participate in both tasks, the Mnemonic Similarity Task (MST) and the Treasure Hunt Task (THT). In each test, participants will sit in front of a computer and play the games using the computer keyboard or a handheld video game controller. Both tests are designed to be challenging and engaging. The MST involves quickly categorizing and remembering photographs of everyday household objects, and the THT involves traveling around a beach scene from a first person point of view, opening treasure chests, and remembering the location of specific treasure items. Our goal in this pilot study is to familiarize ourselves with the procedural aspects of the both the behavioral tests and the exercise components of the study. This includes establishing typical scores for anxiety patients in these behavioral tests, and administering and coaching anxiety patients in an at-home exercise regimen with the collaboration of the laboratory of Richard Sloan. This pilot study will give us the information necessary to design a larger future study including patients and healthy control participants that will minimize subject time burden, while still providing the data necessary to answer our scientific questions.