Alpha Oscillations in the Human Brain Implement Distractor Suppression Independent of Target Selection

Abstract

In principle, selective attention is the net result of target selection and distractor suppression. The way in which both mechanisms are implemented neurally has remained contested. Neural oscillatory power in the alpha frequency band (ϳ10 Hz) has been implicated in the selection of to-be-attended targets, but there is lack of empirical evidence for its involvement in the suppression of to-be-ignored distractors. Here, we use electroencephalography recordings of N ϭ 33 human participants (males and females) to test the preregistered hypothesis that alpha power directly relates to distractor suppression and thus operates independently from target selection. In an auditory spatial pitch discrimination task, we modulated the location (left vs right) of either a target or a distractor tone sequence, while fixing the other in the front. When the distractor was fixed in the front, alpha power relatively decreased contralaterally to the target and increased ipsilaterally. Most importantly, when the target was fixed in the front, alpha lateralization reversed in direction for the suppression of distractors on the left versus right. These data show that target-selection-independent alpha power modulation is involved in distractor suppression. Although both lateralized alpha responses for selection and for suppression proved reliable, they were uncorrelated and distractor-related alpha power emerged from more anterior, frontal cortical regions. Lending functional significance to suppression-related alpha oscillations, alpha lateralization at the individual, single-trial level was predictive of behavioral accuracy. These results fuel a renewed look at neurobiological accounts of selection-independent suppressive filtering in attention.

Frontal theta and posterior alpha oscillations reflect the reactivation of working memory representations following interruptions

“…In accordance with previous studies suggesting a relation between alpha oscillations and the inhibition of irrelevant information (e.g. Bonnefond & Jensen, 2013;Händel et al, 2011;Rösner et al, 2020;Wöstmann et al, 2019), this alpha power increase might reflect the removal of mental representations of the interrupting arithmetic task from working memory after interruption processing had been completed (in the sense of an entire completion/closure of processing the interruption task). Importantly, in the high-demanding condition, alpha power in the resumption phase did not differ as a function of primary task performance and did not return to baseline level prior to retro-cue presentation (see figure 7).…”

Unilateral acoustic degradation delays attentional separation of competing speech

“…The obtained Pearson correlation coefficients were averaged per time window, condition, and individual participants. data (Wöstmann et al, 2019). The dependent-samples non-parametric permutation test was furthermore used to compare the neural encoding accuracy derived from the entire sTRF across conditions.…”

Orienting auditory attention in time: Lateralized alpha power reflects spatio-temporal filtering

“…Thus, alpha lateralization is thought of as a neural implementation of a spatial filter, which relatively increases neural processing of stimuli at relevant spatial locations and suppresses distractors. In direct support of this, we recently used an experimental paradigm to separate target selection from distractor suppression during spatial attention and found that both mechanisms independently induce lateralization of alpha power ( Wöstmann et al., 2019 ).…”