Center for Mathematics, Computing and Cognition Universidade Federal do ABC (UFABC), São Bernardo do Campo, SP, Brazil.
PLoS One. 2021 Sep 27;16(9):e0257378. doi: 10.1371/journal.pone.0257378. eCollection 2021.
Studies investigating the neural mechanisms of time perception often measure brain activity while participants perform a temporal task. However, several of these studies are based exclusively on tasks in which time is relevant, making it hard to dissociate activity related to decisions about time from other task-related patterns. In the present study, human participants performed a temporal or color discrimination task of visual stimuli. Participants were informed which magnitude they would have to judge before or after presenting the two stimuli (S1 and S2) in different blocks. Our behavioral results showed, as expected, that performance was better when participants knew beforehand which magnitude they would judge. Electrophysiological data (EEG) was analysed using Linear Discriminant Contrasts (LDC) and a Representational Similarity Analysis (RSA) approach to investigate whether and when information about time and color was encoded. During the presentation of S1, we did not find consistent differences in EEG activity as a function of the task. On the other hand, during S2, we found that temporal and color information was encoded in a task-relevant manner. Taken together, our results suggest that task goals strongly modulate decision-related information in EEG activity.
研究时间感知的神经机制的研究通常在参与者执行时间任务时测量大脑活动。然而，其中有几项研究仅基于与时间相关的任务，这使得很难将与时间决策相关的活动与其他与任务相关的模式区分开来。在本研究中，人类参与者执行了视觉刺激的时间或颜色辨别任务。在不同的块中呈现两个刺激（S1 和 S2）之前，参与者被告知他们将不得不判断哪个幅度。我们的行为结果表明，正如预期的那样，当参与者事先知道他们将判断哪个幅度时，表现会更好。使用线性判别对比（LDC）和表示相似性分析（RSA）方法分析电生理数据（EEG），以研究是否以及何时编码有关时间和颜色的信息。在 S1 的呈现期间，我们没有发现 EEG 活动随任务的一致差异。另一方面，在 S2 期间，我们发现时间和颜色信息以与任务相关的方式进行编码。总之，我们的结果表明，任务目标强烈调节 EEG 活动中的决策相关信息。
