Healthy subjects will have no history of mental, cognitive or other neurological deficits, adequate hearing and visual acuity (corrected or uncorrected) to follow task instructions and read at least 14 pt. print on a computer screen, and adequate dexterity to press keyboard keys to response stimuli. As with BD subjects, healthy subjects will be right handed, native English speakers, and literate for stimulus sentences. The Mini-Mental State Examination (Folstein et al., 1975) will be administered as a cognitive screen for healthy subjects, using a cut-off score of 27 (of total 30) for inclusion on the protocol.