Over the past ten years, there has been a need to integrate technologies for exogenous stimulation of the brain with endogenous activation of the brain. The predominant methodologies for these are for the former transcranial magnetic stimulation and the latter functional magnetic resonance imaging. These technologies have been isolated from one another because of the high-magnetic field presented by the MRI device. Using TMS in the MRI scanner could not be done due to safety concerns as well as technical incompatibilities relating to the generation of a transient magnetic field (the method of action of TMS). However, in the past five years, MagVenture has developed an MRI compatible rTMS coil system for attachment to their excellent X100 TMS stimulator system. The X100 is capable of single pulse, paired pulse and, now under experimental testing, even repetitive TMS (rTMS). rTMS can be used by scientists and therapists to increase or decrease the excitability of cortical neurons depending on the rate of stimulation. As a result, regional activation or deactivation of the brain is altere and investigators have a short window of opportunity (effectively 10-20 minutes) to probe neuroplasticity. The X100 is capable of up to 100Hz of stimulation which is much greater than other systems on the market and gives investigators a unique capability for cortical modulation. TMS works by transiently changing the magnetic field by delivering current through a stimulating coil. MagVenture has the strongest array of stimulating coils on the market today including the only commercially available TMS coil compatible with an MRI environment. The applications of this technology are detailed in the research plans of this submission and are dependent on the needs of the individual investigators. As such, the X100 TMS-fMRI system provides a versatile tool for numerous researchers to approach questions of interest respective of their research programs. It is the only product on the market than can fulfill these needs. The current application represent interest in the use of the X100 system by 6 VA-affiliated researchers. The Major Group includes: Keith McGregor, PhD; Bruce Crosson, PhD, and Andy Butler, PhD-PT, MBA. The Minor group includes: Paul Garcia, MD., PhD; Joe Nocera, PhD, Catherin Buetefisch, MD, PhD and Michael Borich, PhD. These users represent a strong core of researchers with interests in using the X100 to improve healthcare delivery to Veteran's by improving our understanding of cortical networks.