Irrelevant Predictions: Distractor Rhythmicity Modulates Neural Encoding in Auditory Cortex

Abstract

Dynamic Attending Theory suggests that predicting the timing of upcoming sounds can assist in focusing attention towards them. However, whether similar predictive processes are also applied to background noises and assist in guiding attention away from potential distractors, remains an open question. Here we address this question by manipulating the temporal predictability of distractor sounds in a dichotic listening selective attention task. We tested the influence of distractors temporal predictability on performance and on the neural encoding of sounds, by comparing the effects of Rhythmic vs. Non-rhythmic distractors. Using Magnetoencephalography (MEG) we found that, indeed, the neural responses to both attended and distractor sounds were affected by distractors rhythmicity. Baseline activity preceding the onset of Rhythmic distractor sounds was enhanced relative to Non-rhythmic distractor sounds, and sensory response were suppressed. Moreover, when distractors were Rhythmic, responses to attended sounds were more strongly lateralized to the contra-lateral hemisphere. Behavioral performance also improved in the Rhythmic condition. These combined behavioral and neural results suggest that not only are temporal predictions formed for task-irrelevant sounds, but that these predictions bear functional significance for promoting selective attention and reducing distractibility.