Presentation Information
[P1-35]Neural Correlates of Perceptual Biases in Visual Duration Estimation
*Gianfranco Fortunato1, Valeria Centanino1, Domenica Bueti1 (1. International School for Advanced Studies (Italy))
Keywords:
duration perception,duration tuning,7T-fMRI
Our perception of stimulus duration expands and compresses under the influence of multiple factors such as stimulus features, our physiological state or attentional focus. However, the neuronal mechanisms underlying temporal distortions are not yet well characterized. In the visual system, processing of stimulus duration is supported by distinct tuning profiles: early visual areas exhibit monotonic responses that scale with stimulus duration, whereas downstream cortical regions show unimodal tuning, whereby brain responses peak at preferred durations. In this study, we sought to identify how changes in these tuning profiles relate to biases in duration estimation. Using ultra-high field fMRI, we recorded brain activity of 15 participants engaged in a duration discrimination task under two experimental manipulations known to induce biases in duration judgements. In one session, we modulated perceived duration by altering stimulus speed, which is known to expand the perceived duration of faster stimuli. In a separate session, we employed a duration adaptation protocol, where repeated exposure to a short duration led participants to overestimate the duration of subsequently presented stimuli. Critically, although both manipulations produced similar perceptual biases, they are hypothesized to affect different stages of the neural tuning hierarchy: speed-driven biases are expected to modulate tuning in early visual areas, while adaptation-induced biases are more likely to impact duration tuning in higher-order regions. Using neuronal model-based analysis we aim to identify commonalities and differences in how our experimental manipulations shape duration tuning and its topographical organization. Preliminary results suggest that the two experimental manipulations differentially modulate duration tuning across distinct stages of duration processing within the cortical hierarchy. Overall, our findings might provide new insights into the flexible nature of the neural mechanism underlying our subjective experience of stimulus duration.