Functional Connectivity as a Biomarker of rTMS

Background: Traumatic brain injury (TBI) damages the connections between brain cells. This can lead to problems like memory loss. Repetitive transcranial magnetic stimulation (rTMS) can help improve connections between brain areas in healthy people. Researchers want to see if it can be useful in patients with memory problems after TBI. Objective: To see how repetitive transcranial magnetic stimulation can be used to improve the connections between parts of the brain and whether this will lead to changes in memory. Eligibility: Adults 18-50 years old with TBI who can speak and write in English. Healthy volunteers the same age and English ability. Design: Participants will be screened with a neurological exam and may have a urine pregnancy test. Participants with TBI will have 7-15 visits. Healthy volunteers will have 2-8. At the visits, participants will have all or some of the following: - MRI for about 1 hour. They will lie in a machine that takes pictures in a magnetic field. They will do some memory tasks. - Memory and attention tasks with pictures and with a computer - Questions about their mental state and well-being - TMS: A wire coil is held on the scalp and a short electrical current passes through it. Participants will hear a click and feel a pulling or twitch. They may be asked to make simple movements. rTMS is repeated magnetic pulses in short bursts. They will have this for about 20 minutes. A week after the last visit, some participants will return for a memory test.