Variance of alpha oscillation power corresponds to behavioral performance in spatial auditory attention

Abstract

To analyze an acoustic stream from a desired location, the brain focuses spatial selective attention, which causes shifts in parieto-occipital alpha power (∼8i–12 Hz). We explored whether neurotypical (N = 10) and ADHD (N = 36) adults differ in performance and in the time course of alpha in a spatial attention task. Subjects reported the order of syllables presented in spatially separated streams while EEG was recorded. In each trial, subjects either maintained attention on a central “target” stream (focal attention) or reported the content of a possible “interrupter” from the left (broad attention). Previously, we found that performance correlates with individual differences in how strongly listeners suppress, in focal trials, event-related potentials elicited by the interrupter. We hypothesized that oscillatory alpha signatures would differ for focal and broad attention, reflecting top-down control of spatial attention. Instead, we found that higher consistency in alpha oscillations correlated with better behavioral outcomes. Rather than deploying spatial attention differently in focal and broad conditions, good listeners may use the same listening strategy in both, but be better in staying on task (i.e., overall “focus”). We propose that the unpredictable interrupter engages bottom-up attentional pathways that are functionally separate from previously demonstrated spatial attention steering mechanisms.