Abstract
Subliminal visual stimulus cues can influence implicit motor programming. They are shown to decrease reaction times in both simple and complex motor tasks (Taylor and McCloskey, 1990) and induce deviations in saccade trajectories when presented in the opposite visual hemifield as a prosaccadic target (Van der Stigchel et al., 2009). However, only limited attention has been paid to the effect of subliminal cues on top-down visual processing (Schoeber and Ansorge, 2017). Here, we examined eye movement behavior during a top-down inhibition antisaccade task in comparison with a traditional bottom-up prosaccade task. Participants were asked to fixate on a point in the center of a screen and, as fast as possible, either to prosaccade or antisaccade with respect to a target stimulus appearing randomly on the left or right in the visual field. On 50% of trials, a location-valid prime stimulus was presented prior to the target stimulus, made invisible by metacontrast masking (masks appeared bilaterally on all trials) with individually-calibrated prime duration (~10-40 ms). Reaction times (time from target onset to successful saccade) and eye movement trajectories were measured. We found that a valid prime decreased reaction times by ~25ms (12%) on average in the prosaccade task, but had no effect on reaction times in the antisaccade task. However, examining eye trajectories revealed that while a valid prime decreased the frequency of incorrect initial trajectories by ~50% (p = 0.013) in the prosaccade block, it tended to increase both the frequency and magnitude of incorrect trajectories by ~20% (p = 0.067) and ~8% (p = 0.05) respectively in the antisaccade block. These results suggest that subliminal priming of oculomotor response produces diverging effects on bottom-up vs. top-down components of sensorimotor tasks.