Reduced approach disposition in familial risk for depression: Evidence from time-frequency alpha asymmetries

Abstract

Despite the promising role of alpha and delta power in reflecting reduced approach disposition in depression, to date, it is unclear whether these measures can be employed to identify at-risk individuals. Hence, the present study investigated affective disposition in 32 unaffected individuals with a family history of depression (23 F) and 30 individuals without a family history of depression (21 F) through a data-driven analysis of alpha and delta time-frequency power during the viewing of pleasant, neutral, and unpleasant pictures. Different patterns of posterior alpha asymmetry emerged within each group. Particularly, controls showed greater right posterior alpha desynchronization ~ 600 ms following emotional relative to neutral pictures presentation. Conversely, the group with a family history of depression showed greater posterior left alpha desynchronization only to unpleasant relative to neutral images in a later time window (> 900 ms). Hence, depression vulnerability seems to be characterized by a blunted reactivity to pleasant and delayed reactivity to unpleasant stimuli with a distinct posterior distribution relative to the controls. Finally, the two groups showed a comparable pattern of greater delta power to emotional relative to neutral cues. Overall, initial support was provided for the employment of time-frequency alpha power changes during affective processing in identifying blunted approach disposition in unaffected at-risk individuals.

Fig 1. Time-frequency delta power.

[Panels a and d] Time course of event-related delta power of individuals without a family history of depression (above) and with a family history of depression (below) averaged over the significant electrodes for pleasant (red line), neutral (black line), and unpleasant (blue line) conditions. Shaded areas represent ± standard error of the mean (SEM). [Panels b and e] Mean event-related delta power of each participant in the group without a family history of depression (above) and with a family history of depression (below) averaged over the significant electrodes and time points for pleasant, neutral, and unpleasant conditions. Each circle represents one participant; colored frames represent the mean event-related delta power across all participants and the solid black lines represent ± SEM. *p < .05; ***p < .001. [Panels c and f] Topography of the mean event-related delta power of individuals without a family history of depression (above) and with a family history of depression (below) for pleasant, neutral, and unpleasant conditions.

Fig 2. Time-frequency alpha power.

[Panels a and d] Time course of event-related alpha power of individuals without a family history of depression (above) and with a family history of depression (below) averaged over the significant electrodes for pleasant (red line), neutral (black line), and unpleasant (blue line) conditions. Shaded areas represent ± standard error of the mean (SEM). [Panels b and e] Mean event-related alpha power of each participant in the group without a family history of depression (above) and with a family history of depression (below) averaged over the significant electrodes and time points for pleasant, neutral, and unpleasant conditions. Each circle represents one participant; colored frames represent the mean event-related alpha power across all participants and the solid black lines represent ± SEM. *p < .05; ***p < .001. [Panels c and f] Topography of the mean event-related alpha power of individuals without a family history of depression (above) and with a family history of depression (below) for pleasant, neutral, and unpleasant conditions.