Global attentional selection of visual features is not associated with selective modulation of posterior alpha-band activity.

Abstract

Attending to a single feature, such as color or motion, leads to global modulation of neural processing associated with the representation of the attended features. Alpha-band modulations are hypothesized to be a marker (and even a mechanism) of the modulation of neural processing. By adopting a previously used attentional shifting paradigm, we examined whether alpha-band dynamics are linked to sustained Feature-Based-Attentional (FBA) selection. For this purpose, we presented task-irrelevant flickering random dot kinematograms (RDKs) in the periphery that either did or did not share the to-be-attended color of centrally presented task-relevant RDKs and should thus be subject to global FBA selection. Steady-state visual evoked potentials (SSVEPs) and alpha-band activity associated with these task-irrelevant RDKs were analyzed to quantify FBA modulation. Overall, the SSVEP results replicated previous findings: relative to a pre-cue baseline, SSVEP amplitudes for peripheral RDKs were significantly enhanced when these RDKs shared the to-be-attended color of the central RDKs and were not modulated when they shared the centrally to-be-ignored color. Nevertheless, there were no differences in alpha-band amplitude modulations between signals recorded contralateral to the RDKs sharing the centrally attended color and RDKs sharing the centrally ignored color. Hence, alpha-band modulations seem not to index the sustained global selection of attended over unattended feature values within the same feature dimension.