Traumatic brain injury (TBI) is a prevalent and dangerous occurrence in the United States, with approximately 2 million new cases each year. It is the leading cause of mortality in persons under 45 years old, and a leading cause of disability in all age groups. In adult age groups (ages 21-55) a moderate or even "mild" TBI can result in lifelong deficits in cognition, behavior, and emotional stability that can be described as decreased executive functioning. Such problems impair employment, disrupt stable social relationships and can isolate the individual to a narrow world of disability and reduced opportunity. Researchers have defined many pathological events that occur in the brain early after a TBI, and are beginning to define behavioral consequences in more chronic periods, but the underlying neurobiology for the deficits in executive functioning have not been defined. Strategies to overcome the long-term consequences of TBI include cognitive-behavioral intervention, pharmacological management, assistive technology, environmental manipulation, education and counseling. Little research has been done on the efficacy of these approaches. Use of functional imaging to evaluate the circuitry involved in the cognitive/behavioral aspects of executive function in TBI may reveal insights that could be applied to the evaluation of such attempts at treatment. Therefore, the NINDS, the National Center for Medical Rehabilitation Research in NICHD, and NIMH seek research devoted to functional imaging of brain activity in brain-injured individuals with complex cognitive deficits that constitute altered executive functioning.