Time perception in vision: from sensory processing to network interactions

The ability to perceive and estimate time is a fundamental aspect of human cognition, enabling us to process, predict, and interact with the temporal dimensions of our surroundings. Recent advancements in the field of time perception posit that the perceived duration of sub-second intervals originates from sensory processing - as shown by the biases induced by non-temporal features and by the direct involvement of sensory areas during timing tasks. Beyond this sensory origin, the processing of interval duration further engages a context-independent network of areas, which represent duration in a sensory-independent way. In my PhD work, I ran three distinct studies concerning both the sensory and the distributed nature of temporal processing in the visual domain. First, I examined the mutual dependency between visual motion and time perception revealing a bidirectional interaction between speed and duration processing. Second, I sought to identify the neural correlates of the perceptual bias induced by the stimulus' sensory load, revealing how the amount of sensory information influences perceived duration at an early processing stage. Finally, I provided evidence for a recursive processing of temporal information within the distributed timing network, highlighting the importance of back-projections from a high-order cortical area (SMA) to a primary sensory area (V1). Together, these findings highlight the importance of sensory processing in time perception: sensory cortices encode duration through modality-specific mechanisms and are dynamically modulated by higher-order areas for the integration and refinement of temporal representations. More broadly, this work advances our understanding of how the brain processes and represents time, with implications for both visual perception and temporal cognition.