Abstract
Previous research has highlighted posterior oscillations in the alpha-band to play a key role in goal-directed (top-down) visuospatial attention (Foxe&Snyder 2011). However, the oscillatory signatures of automatically driven (bottom-up) alerting and orienting of attention remain uncertain. Likewise, it is unclear to what extend these automatic processes are influenced by top-down components, such as mid-frontal oscillatory activity in the theta-band. These oscillations are associated with cognitive control processes activated when goal directed bias over habitual responses is needed (Cavanagh&Frank 2014). Here, we employed electroencephalography to investigate the neural correlates of automatic attentional engagement in healthy participants. We utilized an exogenously cued dot detection task. Following a non-predictable spatial cue or no-cue, targets were presented at cued or non-cued positions at four different cue-target delays (ranging from 105.8-705.8ms), known to induce initial attentional benefits and later inhibition-of-return (IOR). This experimental manipulation allowed us to investigate both automatic alerting (cue vs. no-cue independent of space) and automatic (re)orienting (cued vs. uncued position) at early and later stages of spatial attention processes. Between-subject correlations of reaction times (RTs) and alpha-power revealed that individuals who showed an early alerting effect (faster RTs in cue vs. no-cue) exhibited stronger alpha-band desynchronization over occipital regions before target onset (independent of space and hemisphere). Notably, the same analysis also revealed a negative influence of mid-frontal theta activity (P300) over alerting, where individuals with higher central theta-power displayed slower RT. Interestingly, central theta-increases also negatively affected later spatial components of automatic attention (i.e. IOR), where IOR was abolished in individuals with higher theta power. These results suggest an interplay between top-down processes and automatic attention mechanisms, in accordance with cognitive control overriding reflexive processes. They highlight the need to control for the engagement of higher-order computations in order to better understand the neural correlates of automatic processes in isolation.
Meeting abstract presented at VSS 2017