Abstract
A growing body of evidence suggests that in addition to prioritizing relevant information, active suppression of irrelevant information contributes to visual selective attention. Lateralized event-related potentials (ERPs) like the N2pc and PD component can be used to compare attentional processes between hemifields. However, inverted encoding models (IEM) that make use of multivariate signals can track the locus of attention in a more fine-grained manner (Foster et al. 2017; Fahrenfort et al., 2016). Here, we used this approach to track visual attention while subjects searched for a specific target shape in a display that also contained a color singleton distractor (Theeuwes, 1992). In line with past work, the scalp topography of alpha activity allowed tracking of covert orienting to both target and distractor locations, reflecting attention deployment and attentional capture, respectively. Most importantly, a similar analysis of activity in the theta band revealed below-baseline channel activity at the position of color distractors and during a time window that overlapped the PD component indexing distractor suppression. These findings suggest that theta band activity tracks the active suppression of locations occupied by the irrelevant color singletons. In line with this possibility, responses to targets stimuli were slower when the color singleton overlapped the position of the target compared to when no distractor was presented at all. In sum, our results suggest that the topography of theta band activity may provide a precise neural index of the position and timing of distractor suppression.
Meeting abstract presented at VSS 2018