General and Experimental Psychology, Department of Psychology, Ludwig-Maximilians-Universität München, Leopoldstr. 13, 80802, Munich, Germany.
Exp Brain Res. 2023 Aug;241(8):2081-2096. doi: 10.1007/s00221-023-06670-1. Epub 2023 Jul 17.
Despite having relatively accurate timing, subjective time can be influenced by various contexts, such as stimulus spacing and sample frequency. Several electroencephalographic (EEG) components have been associated with timing, including the contingent negative variation (CNV), offset P2, and late positive component of timing (LPCt). However, the specific role of these components in the contextual modulation of perceived time remains unclear. In this study, we conducted two temporal bisection experiments to investigate this issue. Participants had to judge whether a test duration was close to a short or long standard. Unbeknownst to them, we manipulated the stimulus spacing (Experiment 1) and sample frequency (Experiment 2) to create short and long contexts while maintaining consistent test ranges and standards across different sessions. The results revealed that the bisection threshold shifted towards the ensemble mean, and both CNV and LPCt were sensitive to context modulation. In the short context, the CNV exhibited an increased climbing rate compared to the long context, whereas the LPCt displayed reduced amplitude and latency. These findings suggest that the CNV represents an expectancy wave preceding a temporal decision process, while the LPCt reflects the decision-making process itself, with both components influenced by the temporal context.
尽管具有相对准确的定时能力，但主观时间会受到各种上下文的影响，例如刺激间隔和采样频率。几种脑电图 (EEG) 成分与定时有关，包括条件负变 (CNV)、偏移 P2 和定时的晚期正成分 (LPCt)。然而，这些成分在感知时间的上下文调制中的具体作用尚不清楚。在这项研究中，我们进行了两项时间二分实验来研究这个问题。参与者必须判断测试持续时间是否接近短或长的标准。他们不知道的是，我们在保持不同会话中的测试范围和标准一致的情况下，通过操纵刺激间隔（实验 1）和采样频率（实验 2）来创建短和长的上下文。结果表明，二分阈值向整体均值移动，CNV 和 LPCt 都对上下文调制敏感。在短的语境中，CNV 与长的语境相比表现出更快的上升速度，而 LPCt 则表现出幅度和潜伏期的降低。这些发现表明，CNV 代表了在时间决策过程之前的预期波，而 LPCt 反映了决策过程本身，这两个成分都受到时间上下文的影响。
