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  • Chilean brush-tailed mouse ( Octodon degus ): a diurnal precocial rodent as a new model to study visual receptive field properties of superior colliculus neurons

This content will become publicly available on February 1, 2026

Title: Chilean brush-tailed mouse ( Octodon degus ): a diurnal precocial rodent as a new model to study visual receptive field properties of superior colliculus neurons
Lab rodent species commonly used to study the visual system and its development (hamsters, rats, and mice) are crepuscular/nocturnal, altricial, and possess simpler visual systems than carnivores and primates. To widen the spectra of studied species, here we introduce an alternative model, the Chilean degu (Octodon degus). This diurnal, precocial Caviomorph rodent has a cone-enriched, well structured retina, and well-developed central visual projections. To assess degus’ visual physiological properties, we characterized the visual responses and receptive field (RF) properties of isolated neurons in the superficial layers of the superior colliculus (sSC). To facilitate comparison with studies in other rodent species, we used four types of stimuli: 1) a moving white square, 2) sinusoidal gratings, 3) an expanding black circle (looming), and 4) a stationary black circle. We found that as in other mammalian species, RF size increases from superficial to deeper SC layers. Compared with other lab rodents, degus sSC neurons had smaller RF sizes and displayed a broader range of spatial frequency (SF) tunings, including neurons tuned to high SF (up to 0.24 cycles/deg). Also, unlike other rodents, approximately half of sSC neurons exhibited linear responses to contrast. In addition, sSC units showed transient ON-OFF responses to stationary stimuli but increased their firing rates as a looming object increased in size. Our results suggest that degus have higher visual acuity, higher SF tuning, and lower contrast sensitivity than commonly used nocturnal lab rodents, positioning degus as a well suited species for studies of diurnal vision that are more relevant to humans. NEW & NOTEWORTHY Rodent species commonly used to study vision are crepuscular/nocturnal, altricial, and possess simpler visual systems than diurnal mammals. Here we introduce an alternative model, the diurnal, precocial, Octodon degus, a Caviomorph rodent with a well-developed visual system. In this study, we characterize the visual responses of the degus’ superior colliculus. Our results suggest that degus have higher visual acuity than nocturnal rodents, positioning degus as a well-suited species for studies of human like diurnal vision.  more » « less
Award ID(s):
2029980 1656838
PAR ID:
10656060
Author(s) / Creator(s):
; ; ; ; ; ; ;
Corporate Creator(s):
Editor(s):
na
Publisher / Repository:
American Physiological Society
Date Published:
Journal Name:
Journal of Neurophysiology
Edition / Version:
1
Volume:
133
Issue:
2
ISSN:
0022-3077
Page Range / eLocation ID:
358 to 373
Subject(s) / Keyword(s):
rodent caviomorpha diurnal superior colliculus retinocollicular retinotectal optic tectum receptive field visual response properties, receptive field properties
Format(s):
Medium: X Size: 5MB Other: pdf
Size(s):
5MB
Sponsoring Org:
National Science Foundation
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