The Modulating Effect of Top-down Attention on the Optimal Pre-target Onset Oscillatory States of Bottom-up Attention

Abstract

Research in both bottom-up and top-down attention has shown that behavioural performance is related to brain oscillations at the time of stimulus presentation: the angle of the theta phase in bottom-up attention and the inhibition of alpha oscillations in top-down attention. However, whether the conditions most favourable for bottom-up attention change with the addition of top-down cues is unclear. To explore the characteristics of favourable oscillations during bottom-up processing, in experiment 1, 36 participants completed a selective attention task (visual search) without cues. Then, in experiment 2, we examined whether favourable oscillatory characteristics were changed by top-down attentional cues; in this experiment, 62 subjects were asked to perform an attention network task. We found that without anticipation, oscillatory states that were associated with better performance were characterized by lower theta power in the frontal area, higher alpha power in the occipital area, higher beta power in the frontal area, and weaker gamma-theta amplitude-envelope coupling in the parietal area. However, some characteristics that were associated with better performance, including theta power and low beta power, were changed after the addition of different cues. In addition, there were some new characteristics related to improved performance under temporal and spatial anticipation. These results suggest that top-down attention implements a more energy-efficient strategy to process information, optimizing the process of bottom-up attention.