Anticipatory actions require to keep track of elapsed time and inhibitory control. These cognitive functions could be impacted in Parkinson’s disease (iPD). To test this hypothesis, a saccadic reaction time task was used where a visual warning stimulus (WS) predicted the occurrence of an imperative one (IS) appearing after a short delay. In the implicit condition, subjects were not informed about the duration of the delay, disfavoring anticipatory behavior but leaving inhibitory control unaltered. In the explicit condition, delay duration was cued. This should favor anticipatory behavior and perhaps alter inhibitory control. This hypothesis was tested in controls (N = 18) and age-matched iPD patients (N = 20; ON and OFF L-DOPA). We found that the latency distribution of saccades before the IS was bimodal. The 1^st mode weakly depended on temporal information and was more prominent in iPD. Saccades in this mode were premature and could result of a lack of inhibition. The 2^nd mode covaried with cued duration suggesting that these movements were genuine anticipatory saccades. The explicit condition increased the probability of anticipatory saccades before the IS in controls and iPD_ON but not iPD_OFF patients. Furthermore, in iPD patients the probability of sequences of 1^st mode premature responses increased. In conclusion, the triggering of a premature saccade or the initiation of a controlled anticipatory one could be conceptualized as the output of two independent stochastic processes. Altered time perception and increased motor impulsivity could alter the balance between these two processes in favor of the latter in iPD, particularly OFF L-Dopa.

预期行动需要跟踪经过的时间和抑制控制。这些认知功能可能会在帕金森病 (iPD) 中受到影响。为了检验这一假设，使用了一个扫视反应时间任务，其中视觉警告刺激 (WS) 预测在短暂延迟后出现的命令性刺激 (IS) 的发生。在隐性条件下，受试者不被告知延迟的持续时间，不喜欢预期行为但保持抑制控制不变。在显式条件下，延迟持续时间被提示。这应该有利于预期行为，并可能改变抑制控制。这一假设在对照组（N  = 18）和年龄匹配的 iPD 患者（N = 20; 开和关左旋多巴）。我们发现在 IS 之前扫视的延迟分布是双峰的。第^一种模式对时间信息的依赖性较弱，在 iPD 中更为突出。这种模式下的眼跳为时过早，可能是缺乏抑制的结果。第二种^模式与提示持续时间相关，表明这些运动是真正的预期眼跳。_{显式条件增加了对照组和 iPD ON}但不是 iPD _OFF患者在 IS 之前发生预期眼跳的可能性。^{此外，在 iPD 患者中，第}一个序列的概率模式过早反应增加。总之，过早扫视的触发或受控预期扫视的启动可以被概念化为两个独立随机过程的输出。时间感知的改变和运动冲动的增加可能会改变这两个过程之间的平衡，有利于 iPD 中的后者，尤其是关闭左旋多巴。