Effects of pupil size as manipulated through ipRGC activation on visual processing

Mathôt, Sebastiaan; Berberyan, Hermine; Büchel, Philipp; Ruuskanen, Veera; Vilotijević, Ana; Kruijne, Wouter

doi:10.1016/j.neuroimage.2023.120420

Cited by 6 publications

(10 citation statements)

References 69 publications

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“…Specifically, we used an automated procedure to determine participant-specific intensities of red and blue that induced the same initial pupil constriction, based on the assumption that this initial constriction is driven only by rods and cones and not by ipRGCs (for similar calibration procedures, see Kinzuka et al. 2022 ; Mathot et al. 2023 ; Wardhani et al.…”

Section: Methodsmentioning

confidence: 99%

Non-image-forming vision as measured through ipRGC-mediated pupil constriction is not modulated by covert visual attention

Vilotijević,

Mathôt

2024

Cerebral Cortex

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In brightness, the pupil constricts, while in darkness, the pupil dilates; this is known as the pupillary light response (PLR). The PLR is driven by all photoreceptors: rods and cones, which contribute to image-forming vision, and intrinsically photosensitive retinal ganglion cells (ipRGCs), which mainly contribute to non-image-forming vision. Rods and cones cause immediate pupil constriction upon light exposure, whereas ipRGCs cause sustained constriction throughout light exposure. Recent studies have shown that covert attention modulated the initial PLR; however, it remains unclear whether the same holds for the sustained PLR. We tested this by leveraging ipRGCs’ responsiveness to blue light, causing the most prominent sustained constriction. While replicating previous studies by showing that pupils constricted more when either directly looking at, or covertly attending to, bright as compared to dim stimuli (with the same color), we also found that the pupil constricted more when directly looking at blue as compared to red stimuli (with the same luminosity). Crucially, however, in two high-powered studies (n = 60), we did not find any pupil-size difference when covertly attending to blue as compared to red stimuli. This suggests that ipRGC-mediated pupil constriction, and possibly non-image-forming vision more generally, is not modulated by covert attention.

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Section: Methodsmentioning

confidence: 99%

Non-image-forming vision as measured through ipRGC-mediated pupil constriction is not modulated by covert visual attention

Vilotijević,

Mathôt

2024

Cerebral Cortex

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“…Data analysis was performed using the Python (Mathôt et al, 2023) toolbox, which is a high-level toolbox that uses (Gramfort et al, 2013) for general EEG processing, (Mathôt & Vilotijević, 2022) for eye-movement and pupil-size processing, and (Jas et al, 2017) for rejecting and repairing bad EEG channels and epochs. Cluster-based permutation tests were performed using (Mathôt & Vilotijević, 2022).…”

Section: Methodsmentioning

confidence: 99%

“…To what extent do changes in pupil size and changes in environmental luminance, which both affect retinal light exposure, have similar effects on visual processing? We recently used a red-blue induction technique (see also Vilotijević & Mathôt, 2024; Wardhani et al, 2022) to experimentally induce small or large pupils while recording electroencephalographic (EEG) responses to visual stimuli (Mathôt et al, 2023; for related work see Bombeke et al, 2016; Suzuki et al, 2019; Thigpen et al, 2018). We also experimentally manipulated the luminance of these stimuli.…”

Section: Spontaneous Fluctuations In Pupil Size Shape Retinal Respons...mentioning

confidence: 99%

“…hypothesized that larger pupils would lead to increased ERG amplitudes but not, or much less so, to increased ERP amplitudes over occipital cortex; in other words, we hypothesized that retinal responses would not show any brightness constancy with respect to pupil size, but reflect purely the amount of light entering the eye as a function of both stimulus intensity and pupil size, and that only responses from occipital cortex would show a degree of brightness constancy, such that they reflect mainly stimulus intensity (or contrast with the surroundings) and no longer pupil size (cf. Mathôt et al, 2023).…”

Section: Spontaneous Fluctuations In Pupil Size Shape Retinal Respons...mentioning

confidence: 99%

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Spontaneous Fluctuations in Pupil Size Shape Retinal Responses to Visual Stimuli

Mathôt,

Weiden,

Dimigen

2024

Preprint

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Visual perception is shaped at the earliest stage by the size of the eye's pupil, which determines how much light enters the eye and how well this light is focused. But the exact role of pupil size in visual perception is still poorly understood. We recorded pupil size and electrical activity from the retina and brain while healthy human participants viewed full-screen flashes. We found that early retinal responses, which peaked around 25 ms after stimulus onset and predicted subsequent activity over visual cortex, were strongly affected by stimulus intensity. Importantly, pupil size, at least within the range of naturally occurring fluctuations, did not affect the amplitude of these early retinal responses, despite resulting in substantial changes in retinal light exposure. However, the direction of pupil-size change at the moment of stimulus presentation did modulate the amplitude of early retinal responses, which were enhanced during phases of dilation as compared to constriction. Based on these results, we suggest that fast-acting adaptation processes may normalize early retinal responses with respect to changes in retinal light exposure that result from spontaneous changes in pupil size: an initial form of brightness constancy. These results shed new light on, and raise important and previously unasked questions about, the role of pupil size in visual perception.

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“…Importantly, prior to the visual search task, a task-irrelevant probe was presented, which either matched or did not match the color of the memorized target. They found that the pupil constricted more strongly in response to matching probes compared to non-matching probes; they linked this finding to the principle of memory-driven attentional capture, which suggests that stimuli that match internally maintained information capture attention, thus increasing their visual salience, in turn resulting in increased pupil constriction (see also Binda & Murray, 2015b;Mathot et al, 2023).…”

Section: Visual Working Memorymentioning

confidence: 99%

Functional benefits of cognitively driven pupil‐size changes

Vilotijević,

Mathôt

2023

WIRES Cognitive Science

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Pupil‐size changes are typically associated with the pupil light response (PLR), where they are driven by the physical entry of light into the eye. However, pupil‐size changes are also influenced by various cognitive processes, where they are driven by higher‐level cognition. For example, the strength of the PLR is not solely affected by physical properties of the light but also by cognitive factors, such as whether the source of light is attended or not, which results in an increase or decrease in the strength of the PLR. Surprisingly, although cognitively driven pupil‐size changes have been the focus of extensive research, their possible functions are rarely discussed. Here we consider the relative (dis)advantages of small versus large pupils in different situations from a theoretical point of view, and compare these to empirical results showing how pupil size actually changes in these situations. Based on this, we suggest that cognitively driven pupil‐size changes optimize vision either through preparation, embodied representations, or a differential emphasis on central or peripheral vision. More generally, we argue that cognitively driven pupil‐size changes are a form of sensory tuning: a subtle adjustment of the eyes to optimize vision for the current situation and the immediate future.This article is categorized under: Neuroscience > Cognition Neuroscience > Physiology Neuroscience > Behavior

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Effects of pupil size as manipulated through ipRGC activation on visual processing

Cited by 6 publications

References 69 publications

Non-image-forming vision as measured through ipRGC-mediated pupil constriction is not modulated by covert visual attention

Non-image-forming vision as measured through ipRGC-mediated pupil constriction is not modulated by covert visual attention

Spontaneous Fluctuations in Pupil Size Shape Retinal Responses to Visual Stimuli

Functional benefits of cognitively driven pupil‐size changes

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