Focusing attention on relevant information while ignoring distracting stimuli is essential
to the efficacy of working memory. Alpha- and theta-band oscillations have been linked
to the inhibition of anticipated and attentionally avoidable distractors. However,
the neurophysiological background of the rejection of task-irrelevant stimuli appearing
in the focus of attention is not fully understood. We aimed to examine whether theta
and alpha-band oscillations serve as an indicator of successful distractor rejection.
Twenty-four students were enrolled in the study. 64-channel EEG was recorded during
a modified Sternberg working memory task where weak and strong (salient) distractors
were presented during the retention period. Event-related spectral perturbation in
the alpha frequency band was significantly modulated by the saliency of the distracting
stimuli, while theta oscillation was modulated by the need for cognitive control.
Moreover, stronger alpha desynchronization to strong relative to weak distracting
stimuli significantly increased the probability of mistakenly identifying the presented
distractor as a member of the memory sequence. Therefore, our results suggest that
alpha activity reflects the vulnerability of attention to distracting salient stimuli.
