Fronto-striatal overactivation in euthymic bipolar patients during an emotional go/nogo task.

Objective: Although euthymic bipolar patients show minimal manic and depressive symptoms, they continue to show impaired emotional regulation and cognitive functioning. Few studies have directly examined the interference of emotional information with cognitive processes and its underlying cerebral mechanisms in euthymic bipolar patients. The authors examined the emotional modulation of cognitive processes and its underlying neural mechanisms in euthymic bipolar patients.

Method: Seventeen euthymic bipolar patients and 17 healthy comparison subjects underwent functional magnetic resonance imaging (MRI) while performing an emotional and nonemotional go/nogo task. Neural responses associated with the overall task performance, as well as with the impact of emotional information on the task performance, were assessed.

Results: Bipolar disorder patients exhibited increased activity in the temporal cortex, specifically to emotional go/nogo conditions, as well as in the orbitofrontal cortex, the insula, the caudate nuclei, and the dorsal anterior and posterior cingulate cortices when inhibiting emotional stimuli compared with neutral stimuli. Conversely, no global attentional deficits were observed on either a behavioral or neural response level, indicated by similar task performances for all task conditions and similar brain activation patterns when comparing all the go/nogo conditions with the resting state.

Conclusions: The present study provides evidence of an altered emotional modulation of cognitive processing in euthymic bipolar patients, indicated by an overactivation in ventral-limbic, temporal, and dorsal brain structures during emotional go/nogo conditions in patients relative to comparison subjects.