title: Ten days of darkness causes temporary blindness during an early critical period in felines.
abstract: Extended periods of darkness have long been used to study how the mammalian visual system develops in the absence of any instruction from vision. Because of the relative ease of implementation of darkness as a means to eliminate visually driven neural activity, it has usually been imposed earlier in life and for much longer periods than was the case for other manipulations of the early visual input used for study of their influences on visual system development. Recently, it was shown that following a very brief (10 days) period of darkness imposed at five weeks of age, kittens emerged blind. Although vision as assessed by measurements of visual acuity eventually recovered, the time course was very slow as it took seven weeks for visual acuity to attain normal levels. Here, we document the critical period of this remarkable vulnerability to the effects of short periods of darkness by imposing 10 days of darkness on nine normal kittens at progressively later ages. Results indicate that the period of susceptibility to darkness extends only to about 10 weeks of age, which is substantially shorter than the critical period for the effects of monocular deprivation in the primary visual cortex, which extends beyond six months of age.
authors: Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford Street, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2 d.e.mitchell@dal.ca.
authors: Donald E
authors: DE
authors: Mitchell
authors: Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford Street, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
authors: Nathan A
authors: NA
authors: Crowder
authors: Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford Street, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
authors: Kaitlyn
authors: K
authors: Holman
authors: Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford Street, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
authors: Matthew
authors: M
authors: Smithen
authors: Department of Psychology and Neuroscience, Dalhousie University, 1355 Oxford Street, PO Box 15000, Halifax, Nova Scotia, Canada B3H 4R2.
authors: Kevin R
authors: KR
authors: Duffy
mesh_terms: D000367:Age Factors; D000818:Animals; D001522:Behavior, Animal; D001766:Blindness / Q000503:physiopathology* / Q000523:psychology; D002415:Cats; D003423:Critical Period, Psychological; D003624:Darkness; D012683:Sensory Deprivation; D013997:Time Factors; D014792:Visual Acuity
keywords: acuity; critical period; deprivation; visual cortex; visual development; visual loss