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Updated: Jun 24, 2026

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents
Published on: January 24, 2013
Extraocular photoreception and circadian entrainment in nonmammalian vertebrates
Cristiano Bertolucci1, Augusto Foà
1Dipartimento di Biologia and Centro di Neuroscienze, Università degli Studi di Ferrara, Ferrara, Italy.
Abstract:
In mammals both the regulation of circadian rhythms and photoperiodic responses depend exclusively upon photic information provided by the lateral eyes; however, nonmammalian vertebrates can also rely on multiple extraocular photoreceptors to perform the same tasks. Extraocular photoreceptors include deep brain photoreceptors located in several distinct brain sites and the pineal complex, involving intracranial (pineal and parapineal) and extracranial (frontal organ and parietal eye) components. This review updates the research field of the most recent acquisitions concerning the roles of extraocular photoreceptors on circadian physiology and behavior, particularly photic entrainment and sun compass orientation.
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