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Regular version of the site

Book chapter

Poster Presentations, THE EFFECT OF THE ANTISACCADE TASK ON MICROSACCADE SUPRESSION IN THE POSNER CUEING PARADIGM

P. 1866-1866.
Krasovskaya S., Кристьянссон А., MacInnes W.

Microsaccadic eye movements belong to the category of micromovements, such as tremor and drift, though their functional purpose is still debated. Spatial cueing paradigms typically require fixational control, but this does not eliminate all oculomotor activity associated with the preparation of saccades in the cued direction. During the antisaccade task, planning and execution are separate processes and we therefore hypothesise that we may notice reduced microsaccade behaviour during the execution of antisaccade tasks as compared to saccade trials. The study is based on an eyetracking experiment involving 22 participants asked to perform saccades and antisaccades in blocked or mixed sets of trials. Each participant contributed to three main blocks: 50 trials in the fixed saccade block, 50 trials in the fixed antisaccade block, and 200 trials in the mixed saccade — antisaccade condition. In the saccade trials, a green fixation cross is displayed at the centre of the screen, whereas during the antisaccade trials the fixation cross is red, allowing participants to prepare the appropriate response (but not direction) prior to the target. The results of the study imply a strong latency cost of antisaccades as compared to prosaccades and an additional cost of mixed blocks, though these two effects did not interact. Crucially, in the blocked antisaccade trials, we predict that a supressed oculomotor system would lead to a lower occurrence of microsaccades initiated by the participants, in particular the trials where observers did not make erroneous prosaccades. We believe this may be due to participants having enough time to prepare the top-down control of the oculomotor system, which leads to a predictable pattern for each participant, where they either suppress microsaccadic movements completely or do not throughout the entire block. We also predict that in the mixed block participants have less time to prepare the top-down microsaccade suppression and we will test this by comparing data between the saccade, the antisaccade and mixed blocks