Effective sampling time for saccadic eye movement from experiments using a vergence input.

Abstract

The results of analyzing the amplitude and latency of the saccadic component of the compound response are consistent with the notion that the saccadic system operates with a dead zone and an effective sampling time. The size of the dead zone was found to be 0.2 degrees. The latency between the onset of target motion and the onset of the saccade can be divided into three distinct time segments. The first is time for the target image to cross the dead zone boundary. This time segment is inversely proportional to target velocity. The second is the time between the dead zone crossing and the sample. This time segment has a constant duration of 191 msec. The remaining segment is the time between the sample and the saccade. If the target velocity is finite at the time of the sample, the duration of this segment decreases as target velocity increases. If the target velocity is zero at the time of the sample, this segment has a constant duration of about 70 msec.