Neural Repetition Suppression Modulates Time Perception: Evidence From Electrophysiology and Pupillometry.

Area of Science:

• Cognitive Neuroscience
• Psychophysics
• Human Perception

Background:

• Human time perception is subjective and influenced by factors like stimulus intensity and surprise.
• Two main hypotheses explain temporal biases: arousal-driven neural clock speed and magnitude coding of sensory responses.
• Existing experimental designs often confound arousal and sensory magnitude, hindering clear dissociation.

Purpose of the Study:

• To investigate whether sensory response magnitude or arousal levels primarily influence perceived duration.
• To dissociate the effects of sensory magnitude from arousal in time perception.
• To test the magnitude coding hypothesis against the arousal hypothesis in temporal illusions.

Main Methods:

• Two temporal discrimination experiments using flashing stimuli to mark interval start and end.
• Manipulated stimulus location to induce differential sensory responses via neural repetition suppression.
• Measured electroencephalography (EEG) and pupil size to assess neural and physiological correlates.

Main Results:

• Intervals marked by changing stimuli were perceived as longer than those with repeating stimuli.
• Event-related potentials (ERPs), specifically P2, and pupil constriction correlated with perceived duration.
• Surprise and arousal indicators (P3 amplitude, pupil dilation) were not affected by stimulus changes or repetitions.

Conclusions:

• Sensory response magnitude directly impacts time perception, independent of arousal levels.
• Findings support the magnitude coding hypothesis for temporal biases.
• Demonstrates that predictable changes in sensory magnitude can create temporal illusions under constant arousal.