PT  - JOURNAL ARTICLE
AU  - Charlie S. Burlingham
AU  - Saghar Mirbagheri
AU  - David J. Heeger
TI  - A unified model of the task-evoked pupil response
AID  - 10.1101/2021.04.09.439231
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.04.09.439231
4099  - http://biorxiv.org/content/early/2021/04/11/2021.04.09.439231.short
4100  - http://biorxiv.org/content/early/2021/04/11/2021.04.09.439231.full
AB  - The pupil dilates and re-constricts following task events. It is popular to model this task-evoked pupil response as a linear transformation of event-locked impulses, the amplitudes of which are used as estimates of arousal. We show that this model is incorrect, and we propose an alternative model based on the physiological finding that a common neural input drives saccades and pupil size. The estimates of arousal from our model agreed with key predictions: arousal scaled with task difficulty and behavioral performance but was invariant to trial duration. Moreover, the model offers a unified explanation for a wide range of phenomena: entrainment of pupil size and saccade occurrence to task timing, modulation of pupil response amplitude and noise with task difficulty, reaction-time dependent modulation of pupil response timing and amplitude, a constrictory pupil response time-locked to saccades, and task-dependent distortion of this saccade-locked pupil response.Competing Interest StatementThe authors have declared no competing interest.