Alpha connectivity in the frontoparietal network is increased in individuals with familial risk for depression: A resting-state EEG study towards a potential endophenotype

Disturbances within the frontoparietal network (FPN) have been proposed as a plausible neurophysiological marker for cognitive alterations in depression. Although previous electroencephalography (EEG) studies have consistently documented altered synchrony (i.e., increased coherence) within FPN hubs in individuals with depression, EEG dynamics within this network in individuals with a familial predisposition to depression (i.e., in a high-risk sample) remain largely unexplored. To this end, resting state EEG connectivity within the FPN was investigated in non-depressed individuals with a familial risk for depression (FRD+ group; N = 65) and in non-depressed participants without a familial risk for depression (FRD- group; N = 65). EEG analyses were performed using the exact low-resolution electromagnetic tomography software (eLORETA). Significant group differences were observed in alpha connectivity. Compared to the FRD- group, individuals in the FRD+ group showed an increase in alpha connectivity (T = 3.778, p = 0.017) between the right posterior part of the middle temporal gyrus and the midcingulate cortex. Remarkably, this connectivity pattern was positively associated (rho = 0.253, p= 0.042) with the cognitive dimension of the Beck Depression Inventory-II only in the FRD+ group. Overall, these findings suggest that familial risk for depression is associated with a neurophysiological profile characterized by hyperconnectivity within the FPN in the alpha frequency band. This pattern may reflect a compensatory mechanism aimed at overcoming a deficit in semantic integration and maintaining the functionality of the cognitive control network.