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Light‐dependent retinal innervation of the rat superior colliculus
Author(s) -
Prichard J. Roxanne,
Armacanqui Hilda S.,
Benca Ruth M.,
Behan Mary
Publication year - 2007
Publication title -
the anatomical record: advances in integrative anatomy and evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.678
H-Index - 62
eISSN - 1932-8494
pISSN - 1932-8486
DOI - 10.1002/ar.20424
Subject(s) - superior colliculus , pretectal area , biology , retinal , neuroscience , visual system , retina , anatomy , sensory deprivation , midbrain , sensory system , central nervous system , biochemistry
Mammalian retinal projections are divided into two anatomically and functionally distinct systems: the primary visual system, which mediates conscious visual processing, and the subcortical visual system, which mediates nonconscious responses to light. Light deprivation during a critical period in development alters the anatomy, physiology, and function of the primary visual system in many mammalian species. However, little is known about the influence of dark‐rearing on the development of the subcortical visual system. To evaluate whether the early lighting environment alters the anatomy of the subcortical visual system, we examined the retinas and retinofugal projections of rats reared in a 12:12 light/dark cycle or in constant dark from birth to 4 months of age. We found that dark‐rearing was associated with a reduction in the distribution of retinal fibers in the stratum opticum of the contralateral superior colliculus. In contrast to the plasticity of the retinocollicular projection, retinal input to sleep, circadian, and pupillary control centers in the hypothalamus, pretectum, and lateral geniculate complex was unaffected by dark‐rearing. A decrease in retinal innervation of the stratum opticum and intermediate layers of the superior colliculus may account for some of the deficits in multisensory integration that have been observed in dark‐reared animals of several species. Anat Rec 2007. © 2007 Wiley‐Liss, Inc.