Pupillary light reflex of lamprey Petromyzon marinus.

Ala Morshedian, Theodore Henry Huynh, Rikard Frederiksen, Gordon L Fain, Alapakkam P Sampath

Current biology : CB 2021 Jan 25

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The discoveries of the photopigment melanopsin and intrinsically photosensitive retinal ganglion cells (ipRGCs) have revealed novel mechanisms of light detection now known to control several kinds of non-image-forming vision, including regulation of mood, the circadian rhythm, and the pupillary light reflex (PLR). These remarkable discoveries have been made mostly on mammals, but many vertebrates express melanopsin and adjust the diameter of the pupil to the ambient light intensity to extend the operating range of vision and reduce spherical aberration1. We were curious to know whether a PLR controlled by melanopsin is also present in lamprey, which are members of the only remaining group of jawless vertebrates (agnathans) which diverged from all other vertebrates about 500 million years ago2. We now show that lamprey have a robust PLR mediated by melanopsin apparently without any contribution from signals of rods and cones, suggesting that non-image-forming perception emerged long before the radiation of present vertebrate lines and was already present in the late Cambrian. Copyright © 2020 Elsevier Inc. All rights reserved.

Citation

Ala Morshedian, Theodore Henry Huynh, Rikard Frederiksen, Gordon L Fain, Alapakkam P Sampath. Pupillary light reflex of lamprey Petromyzon marinus. Current biology : CB. 2021 Jan 25;31(2):R65-R66