This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study aims to investigate brain abnormalities in idividuals with bipolar disorder and their unaffected siblings compared to healthy control subjects using diffusion tensor and functional magnetic resonance imaging. We hypothesize that individuals with bipolar disorder will exhibit white matter abnormalities and functional alterations in frontostriatal and ventral prefrontal brain regions comapred to healthy volunteers, and that unaffected siblings will demonstrate a pattern of brain abnormalities intermediate between individuals with bipolar disorder and healthy volunteers.