Sleep Deprivation: Effects on Pro-Saccades, Memory-Guided Saccades and Anti-Saccades

Abstract

In this study we investigated the effect of sleep deprivation on different types of saccadic eye movements, namely reflexive visually-triggered saccades, memory-guided saccades and anti-saccades. These types of saccades differ in the extent of voluntary control and hence involve partially different brain structures. This study may reveal parameters and structures being most sensitive to sleep deprivation. Fifteen healthy volunteers participated in one adaptation night and one test night. During the test night half of the subjects (group 1) slept eight hours in a sleep laboratory, the other subjects (group 2) stayed awake. After four weeks the experiment was repeated with group 1 staying awake, group 2 sleeping. All subjects were tested in the evening before and in the morning after the test night (day 1). Furthermore all subjects were retested after one more night during which all were allowed to sleep (day 2). The tests consisted of a series of reflexive pro-saccades, anti-saccades and memory-guided saccades. Saccadic reaction time, peak velocity, and gain were computed for all saccades. Error rate was computed for the anti-saccade task. Before the test night and on day 2 there were no differences between sleep and sleep-deprivation conditions. All saccades showed a significantly reduced peak velocity on day 1 in the sleep deprivation condition. Surprisingly, pro-saccades had normal reaction times but reduced gain. Memory-guided saccades, however, did show prolonged reaction times with normal gain. Reaction times and gain of anti-saccades were not affected. Our data suggest that sleep deprivation does not provoke a general degradation of saccade parameters, but acts on certain parts of the saccadic network.