Emotive interference during cognitive processing in major depression: an investigation of lower alpha 1 activity.

Background Individuals with Major Depressive Disorder (MDD) tend to be more susceptible to distraction by negative emotional material than their non-depressed counterparts. This extends to an enhanced vulnerability to interference from mood-congruent stimuli during cognitive processing. The current study investigated the electrophysiological correlates of competing cognitive and emotional processing demands in MDD. Methods Event-related alpha activity within the lower alpha 1 band was examined during the online information retention phase of a non-emotive WM task with extraneous emotional stimuli (positive, negative and neutral) presented as background images. EEG activity over posterior parietal cortex was compared between 15 acutely depressed and 16 never depressed right-handed women. Results A valence specific dissociation in lower alpha 1 activity was observed between the two groups, consistent with greater attentional resource allocation to positive distracters in control participants and to negative distracters in MDD participants. No group differences were seen when neutral distracters were displayed. Conclusions These results demonstrate that activity within the lower alpha 1 band is sensitive to competing emotional and cognitive processing demands and highlight the importance of posterior parietal regions in depression-related susceptibility to affective distractibility during cognitive processing.