The Influence Of Different Stimulus Conditions On Pro-and Anti-saccades In Humans

Saccades,one of three basic types of eye movement,are usually elicited by the position information,are non-continuous,step-style rapid eye movements.Its role is to quickly change our fixation point,and to focus our fovea centralis retinae which has the highest-resolution on the targets of interest to carry out visual information processing. This study was to explore the influence of different stimulus conditions(time, space, probability) on normal pro- and anti- saccades,to reveal the laws of individual saccades under different sitimulus conditions and obtain saccades model.This study received the following major conclusions:1. The task effects. In anti-saccade task ,saccade latency, saccade amplitude,saccade amplitude gain,direction error rate,corrected saccade latency,corrected saccade amplitude,corrected saccade amplitude gain were significantly higher than those in the pro-saccade task,while there are no difference in the proportion of express saccades,the proportion of anticipatory saccades.2. Gap effects and Overlap effects. Under Gap condition,there are the shortest latency,the hightest direction error rate and proportion of express saccades in both pro- and anti-saccades tasks.And under Overlap condition,there are the longest latency in both pro- and anti-saccades tasks.3. Asymmetric direction effects.There are no difference in horizontal saccade latency,but horizontal saccade latency is shorter than vertical saccade latency.Stimulus were Down in pro-saccade task and Up in anti-saccade task resulted in the longest saccade latency.while stimulus were Up in pro-saccade task and Down in anti-saccade task resulted in the hightest direction error rate.4. The influence of stimulus probability on saccades.In anti-saccade task,the stimulus probability is 1:3 resulted in shortest anti-saccade latency.When the stimulus probability is 1:1 resulted in the hightest direction error rate in both two saccade tasks.5. Stimulus eccentricity effects.In both pro-saccade and anti-saccade tasks, saccade latency, saccade amplitude, saccade amplitude gain,direction error rate,non-response rate,delayed response rate will change immediately according to the variatione of the stimulus eccentricity.In both two saccade tasks,when the stimulus eccentricity of 1°,there are the longest saccade latency,the hightest non-response rate and delayed response rate.As the stimulus eccentricity increase,the saccade amplitude increase.In anti-saccade task,as the stimulus eccentricity increase,the saccade amplitude decrease,while this trend is not significant in pro-saccade task.In pro-saccade task,when the stimulus eccentricity of 1°and 2°,the direction error rate are higher than others.When the stimulus eccectricity of 4°,the direction error rate is the lowest in pro-saccade task,while the hightest in anti-saccade task.And when the stimulus eccentricity of 1°and 10°,anti-saccade direction error rate are lower than others.