scholarly journals PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex

2021 ◽  
Author(s):  
Joel T. Martin ◽  
Joana Pinto ◽  
Daniel Bulte ◽  
Manuel Spitschan
Keyword(s):  
Light Source ◽  
Integrated System ◽  
Pupillary Light Reflex ◽  
Integrating Sphere ◽  
Eye Tracker ◽  
Full Field ◽  
Light Reflex ◽  
Pupillary Light ◽  
Wide Range ◽  
Research Grade

AbstractWe introduce PyPlr—a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine that offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utilities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: (1) pupillometer-style measurement and parametrisation of the PLR to flashes of white light, and (2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.

scholarly journals PyPlr: A versatile, integrated system of hardware and software for researching the human pupillary light reflex

2021 ◽  
Author(s):  
Joel T Martin ◽  
Joana Pinto ◽  
Daniel P Bulte ◽  
Manuel Spitschan
Keyword(s):  
Light Source ◽  
Integrated System ◽  
Pupillary Light Reflex ◽  
Integrating Sphere ◽  
Eye Tracker ◽  
Full Field ◽  
Light Reflex ◽  
Pupillary Light ◽  
Wide Range ◽  
Research Grade

We introduce PyPlr—a versatile, integrated system of hardware and software to support a broad spectrum of research applications concerning the human pupillary light reflex (PLR). PyPlr is a custom Python library for integrating a research-grade video-based eye-tracker system with a light source and for streamlining stimulus design, optimisation and delivery, device synchronisation, and extraction, cleaning, and analysis of pupil data. We additionally describe how full-field, homogenous stimulation of the retina can be realised with a low-cost integrating sphere that serves as an alternative to a more-complex Maxwellian view setup. Users can integrate their own light source, but we provide full native software support for a high-end, commercial research-grade 10-primary light engine which offers advanced control over the temporal and spectral properties of light stimuli as well as spectral calibration utlities. Here, we describe the hardware and software in detail and demonstrate its capabilities with two example applications: 1) pupillometer-style measurement and parametrisation of the PLR to flash of white light, and 2) comparing the post-illumination pupil response (PIPR) to flashes of long and short-wavelength light. The system holds promise for researchers who would favour a flexible approach to studying the PLR and the ability to employ a wide range of temporally and spectrally varying stimuli, including simple narrowband stimuli.

Characteristics of the Pupillary Light Reflex in the Macaque Monkey: Discharge Patterns of Pretectal Neurons

2000 ◽  
Vol 84 (2) ◽  
pp. 964-974 ◽  
Author(s):  
Milton Pong ◽  
Albert F. Fuchs
Keyword(s):  
Light Intensity ◽  
Discharge Rate ◽  
Pupillary Response ◽  
Pupillary Light Reflex ◽  
Physiological Data ◽  
Full Field ◽  
Light Reflex ◽  
Pupillary Light ◽  
Pupillary Constriction ◽  
Discharge Patterns

Anatomical and physiological data have implicated the pretectal olivary nucleus (PON) as the midbrain relay for the pupillary light reflex in a variety of species. To determine the nature of the discharge of pretectal light reflex relay neurons, we recorded their activity in monkeys that were fixating a stationary spot while a full-field random-dot stimulus was flashed on for 1 s. Based on their discharge patterns, neurons in or near the PON came in two varieties. The most prevalent neuron discharged a burst of spikes 56 ms (on average) after the light came on followed by a sustained rate for the duration of the stimulus (burst-sustained neurons). When the light went off, nearly all neurons (33/34) ceased firing, and then all the neurons with a resting response in the dark ( n = 15) resumed firing. Both the firing rate within the burst and the sustained discharge rate increased with log light intensity and the latency of the burst decreased. The burst and cessation of firing were better aligned with the stimulus occurrence than with the onset of pupillary constriction or dilation. Taken together, these data suggest that burst-sustained neurons respond to the visual stimulus eliciting the pupillary change rather than dictating the metrics of the subsequent pupillary response. Electrical stimulation at the site of four of five burst-sustained neurons elicited pupillary constriction at low stimulus strengths after a latency of ∼100 ms. When the electrode was moved 250 μm away from the burst-sustained neuron, the elicited response disappeared. Reconstructions of the locations of burst-sustained luminance neurons place them in the PON or its immediate vicinity. We suggest that PON burst-sustained neurons constitute the pretectal relay for the pupillary light reflex. A minority of our recorded pretectal neurons discharged a burst of spikes at both light onset and light offset. For most of these transient neurons, neither the burst rate nor the interburst rate was significantly related to light intensity. We conclude that these neurons are not involved in the light reflex but subserve some other pretectal function.

scholarly journals Effect of Topical Anti-Glaucoma Medications on Late Pupillary Light Reflex, as Evaluated by Pupillometry

2015 ◽  
Vol 6 ◽  
Author(s):  
Shakoor Ba-Ali ◽  
Birgit Sander ◽  
Adam Elias Brøndsted ◽  
Henrik Lund-Andersen
Keyword(s):  
Pupillary Light Reflex ◽  
Light Reflex ◽  
Pupillary Light

scholarly journals Relationship between Human Pupillary Light Reflex and Circadian System Status

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0162476 ◽  
Author(s):  
Maria Angeles Bonmati-Carrion ◽  
Konstanze Hild ◽  
Cheryl Isherwood ◽  
Stephen J. Sweeney ◽  
Victoria L. Revell ◽  
...  
Keyword(s):  
Circadian System ◽  
Pupillary Light Reflex ◽  
Light Reflex ◽  
Pupillary Light

scholarly journals Pupillary Light Reflex is Altered in Adolescent Depression

2017 ◽  
pp. S277-S284 ◽  
Author(s):  
A. MESTANIKOVA ◽  
I. ONDREJKA ◽  
M. MESTANIK ◽  
D. CESNEKOVA ◽  
Z. VISNOVCOVA ◽  
...  
Keyword(s):  
Nervous System ◽  
Major Depression ◽  
Parasympathetic Nervous System ◽  
Dynamic Balance ◽  
Pupillary Light Reflex ◽  
Control Group ◽  
Light Reflex ◽  
Pupillary Light ◽  
Adolescent Patients ◽  
Depressive Group

Major depressive disorder is associated with abnormal autonomic regulation which could be noninvasively studied using pupillometry. However, the studies in adolescent patients are rare. Therefore, we aimed to study the pupillary light reflex (PLR), which could provide novel important information about dynamic balance between sympathetic and parasympathetic nervous system in adolescent patients suffering from major depression. We have examined 25 depressive adolescent girls (age 15.2±0.3 year) prior to pharmacotherapy and 25 age/gender-matched healthy subjects. PLR parameters were measured separately for both eyes after 5 min of rest using Pupillometer PLR-2000 (NeurOptics, USA). The constriction percentual change for the left eye was significantly lower in depressive group compared to control group (-24.12±0.87 % vs. –28.04±0.96%, p˂0.01). Furthermore, average constriction velocity and maximum constriction velocity for the left eye were significantly lower in depressive group compared to control group (p˂0.05, p˂0.01, respectively). In contrast, no significant between-groups differences were found for the right eye. Concluding, this study revealed altered PLR for left eye indicating a deficient parasympathetic activity already in adolescent major depression. Additionally, the differences between left and right eye could be related to functional lateralization of autonomic control in the central nervous system.

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