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-emotiveWMtaskwith 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 righthanded
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