Jay A Edelman¹, Amy Sultana¹; ¹The City College of New York, Dept. of Biology

Saccadic reaction times (SRTs) are normally in the range of 150-200ms when a visual stimulus is presented on an otherwise blank screen. Edelman et al (2023, 2024) have demonstrated that in an antisaccade (AS) task SRTs were ~30 msec longer when stimuli were present at the two possible target locations (10 deg to the left/right of central fixation) for several hundred msec prior to the peripheral visual stimulus triggering the saccade (peripheral imperative stimulus -- IS). These two studies showing such a prior presentation effect (PPE) used participants > 40 y.o. Moreover, the central fixation duration had an exponential distribution with a mean time of 1500 msec and ISs were small in size. We determined whether a PPE was evident 1) for prosaccades (PS) as well as ASs 2) when the fixation duration was short as well as long 3) for ISs of both large and small size and 4) when participants were young. We collected eye position data from eight undergraduate participants using an Eyelink 1000 video eyetracker (SR Research) at 1000 frames/sec. A three-factor ANOVA was run separately for PSs and ASs with factors of 1) prior target presentation (yes/no) 2) fixation duration (long & exponential / short & uniform) and 3) IS size (large – 3 deg square / small – 1 deg square). For PSs, we found very strong main effects of prior target presentation and fixation duration (p < 0.0001) driven by a PPE and shorter SRTs for long fixation duration, as well as a strong main effect of IS size with shorter SRTs for large stimuli (p=0.004). For ASs, we corroborated our earlier work, but, overall, there was a main effect only of fixation duration (p=0.004). Prior stimulus presence may attenuate the impact of suddenly appearing stimuli on prosaccades, and in certain circumstances, antisaccades.

Acknowledgements: PSC-CUNY grant