Extraocular photoreception and circadian entrainment in nonmammalian vertebrates.
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.
Dipartimento di Biologia and Centro di Neuroscienze, Università degli Studi di Ferrara, Ferrara, Italy.
Cristiano
C
Bertolucci
Augusto
A
Foà
D000818:Animals; D001921:Brain / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D008954:Models, Biological; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D010870:Pineal Gland / Q000502:physiology; D017299:Rod Opsins / Q000502:physiology; D014714:Vertebrates / Q000502:physiology*
D017299:Rod Opsins