Correa Angel, Nobre Anna C
Departamento de Psicología Experimental y Fisiología del Comportamiento, Universidad de Granada, Granada, Spain.
J Neurophysiol. 2008 Sep;100(3):1649-55. doi: 10.1152/jn.90656.2008. Epub 2008 Jul 16.
The current study tested whether multiple rhythms could flexibly induce temporal expectations (temporal orienting) and whether these expectations interact with temporal expectations associated with the passage of time (foreperiod effects). A visual stimulus that moved following a regular rhythm was temporarily occluded for a variable duration (occlusion foreperiod). The task involved making a speeded perceptual discrimination about the target stimulus that reappeared after the occlusion. Temporal-orienting effects were measured by comparing performance and event-related potentials on conditions in which the timing for target reappearance was predictable (valid) versus unpredictable (invalid) according to the rhythm. Foreperiod effects were measured by comparing conditions in which the target was occluded for progressively longer periods of time (short, medium, and long foreperiods) and hence were increasingly predictable. The results showed strong interactions between temporal orienting and foreperiod effects during the facilitation of behavior and neural activity associated with late perceptual and response selection processes. Temporal orienting attenuated the N2 amplitude and decreased the P3 latency only at short foreperiods. Temporal preparation related to foreperiod effects abolished temporal orienting effects at medium and long foreperiods. Likewise, foreperiod effects attenuated the N1 and N2 amplitudes and decreased the P3 latency only in the invalid orienting condition as preparation related to temporal orienting abolished foreperiod effects in the valid condition. This high degree of neural overlap between the effects of temporal orienting driven by rhythms and foreperiod effects associated with the passage of time suggests the involvement of a common mechanism for temporal preparation.
当前的研究测试了多种节奏是否能够灵活地诱发时间预期（时间定向），以及这些预期是否会与与时间流逝相关的时间预期（前周期效应）相互作用。一个按照规则节奏移动的视觉刺激会被暂时遮挡一段可变的时长（遮挡前周期）。任务包括对遮挡后重新出现的目标刺激进行快速的感知辨别。通过比较在目标重新出现的时间根据节奏是可预测的（有效）与不可预测的（无效）条件下的表现和事件相关电位，来测量时间定向效应。通过比较目标被遮挡的时间逐渐变长（短、中、长前周期）且因此越来越可预测的条件，来测量前周期效应。结果显示，在促进与晚期感知和反应选择过程相关的行为和神经活动期间，时间定向和前周期效应之间存在强烈的相互作用。仅在短前周期时，时间定向减弱了N2波幅并缩短了P3潜伏期。与前周期效应相关的时间准备在中、长前周期时消除了时间定向效应。同样，仅在无效定向条件下，前周期效应减弱了N1和N2波幅并缩短了P3潜伏期，因为与时间定向相关的准备在有效条件下消除了前周期效应。由节奏驱动的时间定向效应与与时间流逝相关的前周期效应之间的这种高度神经重叠表明，存在一种用于时间准备的共同机制。
