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 temporal processing from other types of temporally structured brain patterns. In the present study, human participants performed a temporal or color discrimination task of visual stimuli. In different blocks, participants were informed which magnitude they would have to judge before or after presenting the two stimuli (S1 and S2). Our behavioral results showed, as expected, that performance was better when participants knew beforehand which magnitude they would judge. Electrophysiological data (EEG) was analyzed 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 the encoding of temporal information in EEG activity.
bioRxiv Subject Collection: Neuroscience