Fig 7. Transient pupil responses are differentially sensitive to tonic pupil size.

Events of each type were characterised based on above-median or below-median tonic pupil size. Data were averaged across 4 conditions for auditory, blink and saccade panels a,b,c. The response amplitude and shape of auditory responses changes drastically as a function of tonic pupil size. This effect is evidenced by the bar charts (panel d), showing average responses throughout periods in which the response profiles in question were significant in Figs 1 and 3. For each condition there is a significant scaling due to tonic pupil size, this effect is by far the largest for the ‘mean’ response profile, related to the canonical arousal-mediated Response profile.