Pupillary light reflex to light inside the natural blind spot.

Kentaro Miyamoto,Ikuya Murakami

doi:10.1038/srep11862

Abstract

When a light stimulus covers the human natural blind spot (BS), perceptual filling-in corrects for the missing information inside the BS. Here, we examined whether a filled-in surface of light perceived inside the BS affects the size of the short-latency pupillary light reflex (PLR), a pupil response mediated by a subcortical pathway for unconscious vision. The PLR was not induced by a red surface that was physically absent but perceptually filled-in inside the BS in the presence of a red ring surrounding it. However, a white large disk covering the BS unexpectedly induced a larger PLR than a white ring surrounding the BS border did, even though these two stimuli must be equivalent for the visual system, and trial-by-trial percepts did not predict PLR size. These results suggest that some physiological mechanism, presumably the retinal cells containing the photopigment melanopsin, receives the light projected inside the BS and enhances PLR.

Highlights

When a light stimulus covers the human natural blind spot (BS), perceptual filling-in corrects for the missing information inside the BS
We examined whether a filled-in surface of light perceived inside the BS affects the size of the short-latency pupillary light reflex (PLR), a pupil response mediated by a subcortical pathway for unconscious vision
The present study demonstrated that perceptual filling-in of the BS does not affect the short-latency PLR

Summary

Introduction

When a light stimulus covers the human natural blind spot (BS), perceptual filling-in corrects for the missing information inside the BS. The maximum velocity of pupil constriction was typically 10–20%/s in the present study (see Fig. 1b and Supplementary Fig. S1), and was comparable with previous reports of the short-latency PLR in response to bright stimuli[11].

Results

Conclusion