Traumatic brain injury (TBI) affects approximately two million people annually, more than eight times the number diagnosed with breast cancer, and 34 times the number diagnosed with HIV/AIDS (Center for Disease Control, 1999). Cognitive deficits associated with TBI profoundly reduce survivor quality of life after injury. Understanding the nature of cognitive impairments in TBI will provide a basis for development of future remediation strategies and improve functional outcomes following TBI. To this end, the current proposal examines evaluative processes supporting detection of processing conflicts and performance monitoring using high-density event-related potentials, a methodology that provides direct examination of behavioral and neural mechanisms of cognitive control dysfunction in TBI. Self- and other-reported measures of functional outcome will provide information in the domains of cognitive, behavioral and affective expression, as well as awareness of deficits. These constructs will be examined for relationships with neurobiological indices of conflict monitoring and performance adjustment to provide insight into the relationships between cognitive control dysfunction, brain activity reflecting this dysfunction, and functional outcomes. ? ?