A linear chromatic mechanism drives the pupillary response

Tsujimura, Sei-ichi; Wolffsohn, James S.; Gilmartin, Bernard

doi:10.1098/rspb.2001.1775

Cited by 24 publications

(20 citation statements)

References 24 publications

(53 reference statements)

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“…The receptor-excitation space is a natural extension of cone-excitation space. Cone-excitation space uses three fundamentals which correspond to the excitation of the three kinds of retinal cones (Smith & Pokorny 1996;Tsujimura et al 2001Tsujimura et al , 2007. The fundamentals were designed so that the total amount of excitation of L and M cones was equivalent to the photopic luminous efficiency function V(l).…”

Section: (B) Estimation Of Excitation For Photoreceptorsmentioning

confidence: 99%

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Contribution of human melanopsin retinal ganglion cells to steady-state pupil responses

et al. 2010

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The recent discovery of melanopsin-containing retinal ganglion cells (mRGCs) has led to a fundamental reassessment of non-image forming processing, such as circadian photoentrainment and the pupillary light reflex. In the conventional view of retinal physiology, rods and cones were assumed to be the only photoreceptors in the eye and were, therefore, considered responsible for non-image processing. However, signals from mRGCs contribute to this non-image forming processing along with cone-mediated luminance signals; although both signals contribute, it is unclear how these signals are summed. We designed and built a novel multi-primary stimulation system to stimulate mRGCs independently of other photoreceptors using a silent-substitution technique within a bright steady background. The system allows direct measurements of pupillary functions for mRGCs and cones. We observed a significant change in steady-state pupil diameter when we varied the excitation of mRGC alone, with no change in luminance and colour. Furthermore, the change in pupil diameter induced by mRGCs was larger than that induced by a variation in luminance alone: that is, for a bright steady background, the mRGC signals contribute to the pupillary pathway by a factor of three times more than the L-and M-cone signals.

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Section: (B) Estimation Of Excitation For Photoreceptorsmentioning

confidence: 99%

“…The video image was fed into a personal computer and analysed using LABVIEW and IMAQ Vision software (National Instruments) at a frequency of 60 Hz. The pupil was located using thresholding and edge detection techniques, allowing the pupil diameter to be analysed at a resolution of less than 0.001 mm (Tsujimura et al 2001).…”

Section: (D) Led Calibrationmentioning

confidence: 99%

Contribution of human melanopsin retinal ganglion cells to steady-state pupil responses

et al. 2010

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“…Most familiar is a synergistic cone effect that causes the pupil to constrict in response to increased luminance. Illustrating a commonality of principles that characterize neural mechanisms for perception and pupil response, rectified signals from red-green and blue-yellow opponent channels also contribute to the pupil's light response (2)(3)(4)(5)(6)(7).…”

mentioning

confidence: 99%

Opponent melanopsin and S-cone signals in the human pupillary light response

Spitschan¹,

Jain

Brainard³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

169

184

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In the human, cone photoreceptors (L, M, and S) and the melanopsincontaining, intrinsically photosensitive retinal ganglion cells (ipRGCs) are active at daytime light intensities. Signals from cones are combined both additively and in opposition to create the perception of overall light and color. Similar mechanisms seem to be at work in the control of the pupil's response to light. Uncharacterized however, is the relative contribution of melanopsin and S cones, with their overlapping, short-wavelength spectral sensitivities. We measured the response of the human pupil to the separate stimulation of the cones and melanopsin at a range of temporal frequencies under photopic conditions. The S-cone and melanopsin photoreceptor channels were found to be low-pass, in contrast to a band-pass response of the pupil to L-and M-cone signals. An examination of the phase relationships of the evoked responses revealed that melanopsin signals add with signals from L and M cones but are opposed by signals from S cones in control of the pupil. The opposition of the S cones is revealed in a seemingly paradoxical dilation of the pupil to greater S-cone photon capture. This surprising result is explained by the neurophysiological properties of ipRGCs found in animal studies. Distinct neural pathways process signals originating in cone photoreceptors for visual perception. Luminance pathways combine signals from separate classes of cones synergistically, providing a spectrally broadband indication of the overall light intensity at each location in the retinal image. Red-green and blue-yellow chromatic channels combine signals from separate classes of cones in an opponent (subtractive) fashion, providing sensitivity to the relative spectral content of light and supporting the perception of color independent of luminance (1).A parallel set of pathways contributes to the response of the pupil of the eye to light. Most familiar is a synergistic cone effect that causes the pupil to constrict in response to increased luminance. Illustrating a commonality of principles that characterize neural mechanisms for perception and pupil response, rectified signals from red-green and blue-yellow opponent channels also contribute to the pupil's light response (2-7).Recently, it has been discovered that mammalian retinas contain an additional photoreceptor class that also operates under daylight conditions. Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin, which has a peak spectral sensitivity (480 nm) between that of S and M cones (8, 9). Among other, "non-image-forming" functions of the eye, melanopsin-containing ipRGCs contribute to a delayed and sustained constriction of the pupil (10). Studies in patients with loss of photoreceptor function (11) suggest that melanopsin may also contribute to conscious visual perception.The discovery of an additional photoreceptor class raises the fundamental question of how melanopsin signals are combined with those from the cones. Do melanopsin signals add to con...

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“…The difference in latency was approximately 280 ms. Our results showed that a difference in time when initiating constriction between the mRGC and the light flux condition was 189 ms and the difference in time to the peak was 131 ms. In humans, the pupillary responses to luminance and chromatic stimuli were different, suggesting a contribution of post‐receptoral mechanisms such as |L+M| luminance and |L−M| cone‐opponent mechanisms to the pupillary pathway 46,47 …”

Section: Discussionmentioning

confidence: 99%

Delayed response of human melanopsin retinal ganglion cells on the pupillary light reflex

Tsujimura

Tokuda

2011

Ophthalmic Physiologic Optic

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The results indicate that we successfully demonstrated the pupillary response to mRGCs under conditions where mRGCs are isolated in humans. Furthermore, the data confirm that the delayed response disappeared when the stimulus is presented as a square-wave pulse and not weighted by a sinusoid. The similarity of time courses for the earlier phase of pupillary responses to all stimuli suggested that these transient pupillary responses were driven by a single mechanism, which is perhaps associated with cone-mediated signals.

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A linear chromatic mechanism drives the pupillary response

Cited by 24 publications

References 24 publications

Contribution of human melanopsin retinal ganglion cells to steady-state pupil responses

Contribution of human melanopsin retinal ganglion cells to steady-state pupil responses

Opponent melanopsin and S-cone signals in the human pupillary light response

Delayed response of human melanopsin retinal ganglion cells on the pupillary light reflex

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