Motor-related neural oscillations in mood disorders

Motor symptoms are common in mood disorders and are related to poor treatment responses, unfavourable illness prognosis, and increased suicidal ideation. However, neural mechanisms of impaired motor function remain unclear. Neural oscillatory activity in the theta and beta band within the cortico-cortical motor circuit is believed to reflect aspects of motor control. Here, we explored motor function and motor-related neural oscillations in individuals with mood disorders. 144 patients with bipolar disorder (BD), 136 patients with major depressive disorder (MDD), and 125 control subjects completed a Go/No-Go task during magnetoencephalography recording. Moreover, 21 MDD patients and 16 BD patients underwent the second MEG scanning during follow-up. Trail Making Test A and B were used to measure motor performance. Oscillation-derived measures such as inter trial phase coherence, event-related spectral perturbation, phase locking value and phase amplitude coupling (PAC) within the supplementary motor area (SMA) and primary motor cortex (M1) were compared across the groups. Patients with BD exhibited poorer motor performance compared to those with MDD. BD patients showed reduced theta event-related synchronization and ITPC, along with enhanced beta event-related desynchronization. Conversely, a reduction in theta-beta PAC within SMA was observed in the MDD group. These divergent patterns underscore distinct neurophysiological alterations associated with motor function impairments across the two mood disorder groups, highlighting the complexity and specificity of oscillatory and connectivity changes linked to their pathophysiology. Future research should investigate the potential value of neural oscillations in predicting clinical and functional outcomes to guide the development of neurobiologically informed interventions.