Evidence That Indirect Inhibition of Saccade Initiation Improves Saccade Accuracy – Research Paper Example

The paper “Evidence That Indirect Inhibition of Saccade Initiation Improves Saccade Accuracy" is a perfect example of a term paper on health sciences & medicine. Our visual system is designed in a way that an individual must move their eyes to catch a glimpse of the surrounding environment. Different targets present themselves in selecting the next visual target and thus the process is competitive. In determining the depth of the competition, saccade response time is inhabited. Previous research depicts inaccuracy in saccadic eye-movement in the presence of a local distracter. This they attributed to the target and the distracter using the same route. On the other hand, a remote distracter increases the accuracy of a visual target since a remote distracter acts via an indirect route slowing saccade initiation but increasing accuracy.

This article is addressing the accuracy of saccades and evaluating if the presence of remote and local distracters is affecting this accuracy. Visual targets and independent while the local and remote distracters are independent. The hypothesis to this research work is “Saccade latency induced by remote and local distracters affect the saccade accuracy of a visual target,” Its alternative hypothesis is that “Saccade latency induced by remote and local distracters does not affect saccade accuracy of a visual target”

Methods
The research carried on eight observers between the ages nineteen and twenty-one were in accordance to standards described in the 1964 Declaration of Helsinki. A sample of innocent observers was randomly selected after they consented to participate in the study. Every observer went through a trial process to familiarise with the timing and configuration of the experiments. With the head movements restricted by the use of chin rest, it was possible to record the eye movements using an eye-tracker with a sampling rate of 500 Hz. It was only at the beginning of eye-tracking that the instruments were calibrated, otherwise on the realization of a big difference between the initial calibration and validation retest. The fixation point appeared at the middle of the mirror while a remote distracter, local distracter, and target distracters on the sides.

Results
From figure two, that shows a monotonic increase in saccade latency of a two-factor SOA distracter with an average probability of 0.01. Saccade latency was found to increase as the SOA of the fixation marker changed from a gap (-150 and -75) to overlap (75 and 150) (McSorley 76). The placement of the remote distracter or SOA did not affect the results. Form the results in table three, as the latency of the saccades increased the corresponding accuracy improves. The angular error of the saccade landing position was used to determine this.

Discussion
Initially, it was not clear whether the distracter distances from the target or the timing difference between the distracter and target onset give the remote distracter effect. However, the accuracy of a saccade is dependent only on the latency of the saccades in disregard to remote distracters. Involuntary increases in saccade latency brought by either remote or local distracters only inhibit the fixation process but improve the localization of the target. This happens after a competition of visual stimuli until the highest point of activation make the eye focus on the target.