Inclusion Criteria- Mild, moderate and severe traumatic brain injury or a cerebral vascular accident (Stroke)
- All subjects will be between the ages of 18 and 70 years
- Free from significant psychiatric history (such as schizophrenia or bipolar disorder), due to the potential influence of such disorders on cognitive functioning
- Free of current alcohol or drug as these factors have been shown to negatively affect cognitive abilities.
Exclusion Criteria- Potential participants will be excluded if they are currently taking benzodiazepines or neuroleptics due to their potential effects on cognition.
- Participant will be excluded if they are unable to comprehend the English language, either verbally or written.
- Participants will be excluded from the magnetic resonance imaging (MRI) scan portion of the study if they contain metal in their body that is not compatible with the MRI scan.