An EEG investigation of temporal processing across stimulus configurations

The sensory content and temporal structure of stimuli consistently bias the percept of duration. Previous studies revealed that intervals filled with continuous sensory input are perceived as longer compared to stimuli only marked at their onset and offset, a phenomenon referred to as 'filled duration illusion'. It remains unclear whether these distinct stimulus formats are measured by a common timing mechanism. In our study, we aimed to examine potential differences in the EEG correlates of temporal processing for filled, flanked and empty stimuli. We tested participants in a temporal reproduction task under each stimulus condition. Behavioral results confirmed that stimulus configuration significantly biases perceived duration. Event-related potential (ERP) analysis revealed duration effects predominantly in the occipito-parietal region, so that waveforms were modulated by duration in a gradual and ordered fashion under all stimulus conditions. By employing Representational Similarity Analysis (RSA), we correlated perceptual biases induced by stimulus types to neural activity. Specifically, we report a stronger representation of behavior beyond the representation of pure duration, indicating neural encoding of stimulus-induced biases at occipito-parietal electrodes. These findings suggest similarities in how duration is represented across stimuli, as underscored by ERP patterns, while emphasizing the relation between stimulus-induced biases and neural activity before and after stimulus offset. Our results highlights the intricate interplay between sensory input and temporal perception, revealing the integration of stimulus-induced distortions in the neural representation of time.