Braun D, Breitmeyer B G
Abteilung für Klinische Neurologie und Neurophysiologie, Universität Freiburg, Federal Republic of Germany.
Exp Brain Res. 1988;73(3):546-52. doi: 10.1007/BF00406613.
Saslow (1967) and Fischer and Ramsperger (1984) found that saccadic reaction time (SRT) depends on the interval between the fixation point offset and the target onset. Using a continuously visible fixation point, we asked whether a similar function would be obtained if subjects attended to a peripherally viewed point extinguished at variable intervals before or after the target onset. The interval was varied between -500 ms (i.e., attention stimulus offset after saccade target onset = overlap trials) and 500 ms (i.e., attention stimulus offset before saccade target onset = gap trials). The results show a constant mean SRT of about 240 ms for overlap trials, and a U-shaped function with a minimum of 140 ms, at a gap duration of 200 ms, for gap trials. These findings suggest that saccadic latencies do not depend on the cessation of fixation per se, but rather on the disengagement of attention from any location in the visual field. The time required for subjects to disengage their attention is approximately 100 ms. This disengaged state of attention--during which short latency (express) saccades can be made--can be sustained only for a gap duration of 300 ms. At longer gap durations mean SRTs increase again.
萨斯洛（1967年）以及菲舍尔和兰斯珀格（1984年）发现，扫视反应时间（SRT）取决于注视点偏移与目标出现之间的间隔。使用持续可见的注视点，我们探讨了如果让受试者关注在目标出现之前或之后以可变间隔熄灭的周边视位点，是否会得到类似的函数关系。该间隔在-500毫秒（即扫视目标出现后注意力刺激消失 = 重叠试验）和500毫秒（即扫视目标出现前注意力刺激消失 = 间隙试验）之间变化。结果显示，重叠试验的平均SRT恒定约为240毫秒，间隙试验则呈现出U形函数，在间隙持续时间为200毫秒时最小值为140毫秒。这些发现表明，扫视潜伏期并非取决于注视本身的停止，而是取决于注意力从视野中任何位置的脱离。受试者脱离注意力所需的时间约为100毫秒。这种注意力脱离状态——在此期间可以进行短潜伏期（快速）扫视——只能在300毫秒的间隙持续时间内维持。在更长的间隙持续时间下，平均SRT会再次增加。
