Jüttner M, Wolf W
Institut für Medizinische Psychologie, Universität München, Germany.
Biol Cybern. 1994;70(3):247-53. doi: 10.1007/BF00197605.
Express saccades predominantly occur in experiments employing the gap paradigm where the target onset is separated from the fixation point offset by a blank period. Their relative frequency is distinctly influenced by catch trials (i.e. trials without a saccadic target) mixed into the stream of regular target trials. Generalizing this concept for other stimulus uncertainties (direction, amplitude), we found that the preparation time of a saccade depends on both the type of uncertainty used and the sequence of trial type (e.g., target vs catch, left vs right) in the experiment. This stimulus sequence effect is most prominent for catch trials. A similar but less pronounced effect can still be observed in the case of direction uncertainty but not in that of amplitude uncertainty. A two-state Markov process model is proposed which is based on the dichotomy of express and regular saccades in the gap paradigm. According to this model the actual state of the saccadic system, which determines the type of saccade just in preparation, depends on the "trial history". The implications for models of saccade programming are discussed.
快速扫视主要出现在采用间隙范式的实验中，在该范式中，目标呈现与注视点消失之间有一段空白期。它们的相对频率受到混入常规目标试验流中的捕捉试验（即没有扫视目标的试验）的显著影响。将这一概念推广到其他刺激不确定性（方向、幅度）时，我们发现扫视的准备时间取决于所使用的不确定性类型以及实验中试验类型的序列（例如，目标试验与捕捉试验、向左与向右）。这种刺激序列效应在捕捉试验中最为显著。在方向不确定性的情况下仍可观察到类似但不太明显的效应，而在幅度不确定性的情况下则观察不到。提出了一种双态马尔可夫过程模型，该模型基于间隙范式中快速扫视和常规扫视的二分法。根据该模型，决定即将准备的扫视类型的扫视系统的实际状态取决于“试验历史”。文中讨论了其对扫视编程模型的影响。
