A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction
- Johns Hopkins University, United States
- Beth Israel Deaconess Medical Center, United States
- University of Marlyand, United States
- National Institutes of Health, United States
- Harvard Medical School, United States
Abstract
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters. Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate , but adapt within minutes. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics.
Article and author information
Author details
William Thomas Keenan
Funding
National Eye Institute (R21)
- William Thomas Keenan
- Alan C Rupp
- Samer S Hattar
National Institute of General Medical Sciences (RO1)
- William Thomas Keenan
- Alan C Rupp
- Samer S Hattar
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All mice were housed according to guidelines from the Animal Care and Use Committee of Johns Hopkins University (Protocol # MO16A212), and used protocols approved by the JHU animal care and use committee.
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction
eLife 5:e15392.
https://doi.org/10.7554/eLife.15392
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