Abstract
In real world vision, attention is guided by top-down (voluntary) or bottom-up (involuntary) influences, with (overt) or without (covert) concomitant eye movements. Cognitive neuroscience studies of covert attention have predominantly investigated top-down attention using attention-directing cues, although self-generated shifts of spatial attention (willed attention) are increasingly of interest (e.g., Bengson et al., 2014; Nadra et al., 2022). Studies of the precursor brain activity during willed attention have focused on signals that preceded shifts of covert spatial attention, but not other forms of attention. In an overt attention visual search paradigm, we assessed whether the direction of a first saccade after held fixation can be predicted by the pattern of brain electrical activity in the period prior to the onset of the search array and first saccade. The stimuli and task were designed so that the subjects could neither predict the timing of search array onset, nor was covert spatial attention sufficient to find the target in the array. Using support vector machine decoding of EEG alpha (8-12 Hz) oscillations in the foreperiod, we found that the scalp EEG pattern predicted the direction of the first saccade as early as 1400 milliseconds, lasting until 700 milliseconds before the onset of the search array. The timing and pattern of the predictive EEG signals differed, however, from that found previously during covert willed attention.