Brain regions beyond the visual cortex are relevant to subjective time prediction from fMRI salient events in a visual naturalistic context.

Time perception is an essential part of human experience and can be distorted by features of daily stimuli, causing variations relative to actual time. This study aimed to test the hypothesis that subjective time results from the accumulation of salient events and investigate the neural bases of this perceptual processing, while using a publicly available dataset obtained and analyzed in a previous study. Three approaches were used with fMRI data from participants who watched and estimated the duration of silent videos in an MRI scanner. In the first approach, using a functional parcellation of 360 cortical regions, we showed that salient events in functional networks beyond the visual one also had a significant association with subjective time (normalized bias): the dorsal attention network, the cingulo-opercular network, and the somatomotor network. In the second approach, using an Long-Short Term Memory (LSTM) deep learning model, it was not possible to predict normalized bias from fMRI trial-by-trial time series within any functional network. In the last approach, functional connectivity between the 360 cortical regions and within the visual network showed no consistent association with subjective time. The results suggest that regions in additional functional networks may be important for duration quantification in the context of visual stimulation, although the approach based on salient events still requires further validation. Furthermore, features such as functional connectivity and fMRI time-series did not show direct association with the normalized bias.