抄録
Smooth pursuit is an ocular function that allows us to have a good vision of a moving stimulus. It has been demonstrated that the latency of pursuit is affected by introducing a temporal gap between the extinction of the central fixated target and the appearance of the eccentric, moving target (Krauzlis and Miles, 1996). Here, we examined whether the presence of temporal gaps affects the gain of visuo-motor transmission, by comparing ocular responses to a brief motion (perturbation) of a visual stimulus with and without a preceding gap in 3 human subjects. At the beginning of each trial, a stationary, green spot (fixation target) was appeared on the center of the screen. After the subject established a fixation, a red spot turned on at 1 deg right/left of the green spot. Then the green spot turned off and the red spot moved at 20 deg/s for 0.6 s. In perturbation trials, a brief motion (perturbation) of the red spot (sinusoidal motion of 10 Hz at the peak velocity of 20 deg/s for 0.1 s) was inserted before the ramp motion. These trials allowed us to measure the gain of visuo-motor transmission at the initiation of pursuit. In gap-perturbation trials, the green spot was blinked for 0.2 s immediately before the perturbation, to measure the gain of visuo-motor transmission in the presence of a preceding gap. We found that the ocular responses to the perturbations were significantly larger when there was a blink than when there was no blink. This result suggests that the presence of temporal gaps increases the gain of visuo-motor transmission. [Jpn J Physiol 55 Suppl:S177 (2005)]
