Influence of sports experience on distribution of pro-saccade reaction time under gap condition

Kenji Kunita,Katsuo Fujiwara

doi:10.1186/s40101-022-00277-1

Kenji Kunita, Katsuo Fujiwara

Open Access

https://doi.org/10.1186/s40101-022-00277-1

Copy DOI

Abstract

BackgroundPrevious studies indicated that substantial individual variation exists in the distribution of pro-saccade reaction times under gap condition. To investigate the influence of sports experience on the distribution, we examined distribution of the pro-saccade reaction time under overlap and gap conditions, for the basketball club, table tennis club, and non-sporting control groups.MethodsSubjects performed pro-saccade tasks under the overlap and gap conditions, in which the intentional and reflexive disengagement of fixation are important, respectively. Under the overlap condition, the central fixation point was illuminated for a random duration of 1–3 s, then the fixation point was turned off. Just after the switch-off of the fixation point, one of the peripheral targets was illuminated for a duration of 1 s. The visual stimulus under the gap condition was almost the same as that under the overlap condition. However, only the temporal gap between the switch-off of the fixation point and the onset of the target differed between those conditions. The gap duration in the gap condition was set at 200 ms. The mean of median value of the bandwidth showing the earliest peak in the histogram was calculated for each group. Thereafter, for each subject, the bandwidth showing the earliest peak under the gap condition was defined as the criterion bandwidth (0 ms bandwidth). Based on this criterion bandwidth, the mean of the relative frequency was calculated for every 10 ms of bandwidth, for the overlap and gap conditions, in each group.ResultsUnder the overlap condition, for all subjects, the pro-saccade reaction times showed unimodal distribution. The means of the median value of the bandwidth showing the earliest peak for the basketball and table tennis groups (approximate 170 ms) were significantly earlier than that for the control group (approximate 190 ms). Under the gap condition, the distribution was bimodal for 11 of 15 subjects in the basketball group and for 5 of 15 subjects in the control group. In the table tennis group, the distribution was not bimodal but unimodal for all 15 subjects. For the basketball group, mean of the relative frequency showed bimodal distribution with approximate 120 ms and 170 ms peaks. For the table tennis and control groups, the mean of the relative frequency showed unimodal distribution with approximate 130 ms and 140ms peak, respectively.ConclusionsThe present study indicated that under the gap condition, the sports experience influenced on the distribution of the pro-saccade reaction time. The pro-saccade reaction time under the condition would show a distinct bimodal distribution for the basketball group and show a distinct and early unimodal distribution for the table tennis group. It was suggested that the physiological factor leading the group difference in the distribution was the effect of sports experience on the disengagement function of fixation.

Highlights

Previous studies indicated that substantial individual variation exists in the distribution of pro-saccade reaction times under gap condition
It was suggested that the physiological factor leading the group difference in the distribution was the effect of sports experience on the disengagement function of fixation
In relation to the involvement of the higher saccade system associated with intentional disengagement, the pro-saccade reaction times under the overlap condition show a unimodal distribution with the peak ranging from 180 to 200 ms [13,14,15]

Summary

Introduction

Previous studies indicated that substantial individual variation exists in the distribution of pro-saccade reaction times under gap condition. Disengagement of fixation has been investigated using overlap and gap conditions, in which the timing between switch-off of the central fixation point and lighting of the visual target are operated. Intentional disengagement of fixation is important for saccade generation, which is related to the frontal eye fields in the higher saccade system [13]. In relation to the involvement of the higher saccade system associated with intentional disengagement, the pro-saccade reaction times under the overlap condition show a unimodal distribution with the peak ranging from 180 to 200 ms [13,14,15]. The gap condition is one in which the central fixation point is turned off some time (mainly 200 ms) before emergence of the peripheral visual target [13, 15, 16]. Reaction time shows a bimodal distribution, with the peak at 100–120 ms associated with the reflexive disengagement of fixation (first peak), in addition to the abovementioned peak of 180–200 ms associated with the intensive disengagement of fixation, similar to the situation in the overlap condition (second peak) [13, 17, 18]

Methods

Results

Discussion

Conclusion