Background Bipolar I disorder is defined by the occurrence of mania. The presence of mania, coupled with a course of illness characterized by waxing and waning of affective symptoms, suggests that bipolar disorder arises from dysfunction of neural systems that maintain emotional arousal and homeostasis. We used functional magnetic resonance imaging (fMRI) to study manic bipolar subjects as they performed a cognitive task designed to examine the ventrolateral prefrontal emotional arousal network. Methods We used fMRI to study regional brain activation in 40 DSM-IV manic bipolar I patients and 36 healthy subjects while they performed a continuous performance task with emotional and neutral distracters. Event-related region-of-interest analyses were performed to test the primary hypothesis. Voxelwise analyses were also completed. Results Compared with healthy subjects, the manic subjects exhibited blunted activation to emotional and neutral images, but not targets, across most of the predefined regions of interest. Several additional brain regions identified in the voxelwise analysis also exhibited similar differences between groups, including right parahippocampus, right lingual gyrus, and medial thalamus. In addition to these primary findings, the manic subjects also exhibited increased activation in response to targets in number of brain regions that were primarily associated with managing affective stimuli. Group differences did not appear to be secondary to medication exposure or other confounds. Conclusions Bipolar manic subjects exhibit blunted brain fMRI response to emotional cues throughout the ventrolateral prefrontal emotional arousal network. Disruption of this emotional network may contribute to the mood dysregulation of bipolar disorder.

The objective of this study was to examine differences between fluent English-speaking ethnically diverse (ED) individuals (from Hispanic, Asian and Middle-Eastern descent) and monolingual English-speaking Anglo-Americans (MEAA) on commonly used tests of information processing and attention. A sample of 123 (84 ED and 39 MEAA) healthy individuals participated. The results revealed that the MEAA group outperformed the ED group on Trail Making Test Part B, Stroop B and C, and Auditory Consonant Trigrams (18s delay condition). Additionally, a host of acculturation variables such as score on a formal acculturation scale, amount of time educated outside of the U.S., and the amount of English spoken when growing up correlated with these various neuropsychological tests. The findings from this study highlight the importance of taking acculturation into account for fluent English-speaking ED individuals when administering and interpreting neuropsychological tests.

Executive dysfunction may be a mediating vulnerability indicator of bipolar disorder that is strongly related to mood state, but only modestly related to chronicity of illness during the early disease course.

No abstract