Functional Magnetic Resonance Imaging Study of Inhibitory Control in Bipolar Disorder and Major Depressive Disorder

Bipolar disorder and unipolar depressive disorder are two chronic mood disorders associated with a significant social impact, even during euthymic phases. Their differential diagnosis remains complex, particularly when bipolar disorder begins with a depressive episode. Identifying distinctive markers between these pathologies therefore represents a major clinical and economic challenge, as appropriate mood-stabilizing treatment can reduce healthcare costs and improve patients' functional outcomes. Among potential biomarkers, executive functions-and more specifically inhibition-have received particular attention. Inhibitory deficits are observed in both disorders, including during euthymic states, and also among first-degree relatives, suggesting their potential as cognitive and cerebral endophenotypes. These deficits may help explain the difficulties in emotion regulation and impulsivity frequently observed in mood disorders. Two components of inhibition are distinguished: 1. Behavioral inhibition, which refers to the ability to stop an ongoing response. 2. Interference control, which refers to the ability to resist distraction. These processes rely on partially distinct neural networks and operate at different stages of information processing. The few studies comparing these two components in bipolar disorder have shown contradictory results, and neuroimaging investigations have only partially explored these mechanisms, particularly their emotional dimension. It is, however, well established that patients with bipolar or depressive disorders show greater difficulties in executive tasks involving emotional stimuli than in purely cognitive tasks. The study is expected to reveal: * Differences in brain activation between euthymic bipolar and unipolar depressive patients in regions involved in inhibitory control, modulated by the emotional content of the task. * Distinct cognitive performance profiles according to pathology, reflecting specific alterations in inhi