title: Behavioral evaluation of visual function of rats using a visual discrimination apparatus.
abstract: A visual discrimination apparatus was developed to evaluate the visual sensitivity of normal pigmented rats (n=13) and S334ter-line-3 retinal degenerate (RD) rats (n=15). The apparatus is a modified Y maze consisting of two chambers leading to the rats' home cage. Rats were trained to find a one-way exit door leading into their home cage, based on distinguishing between two different visual alternatives (either a dark background or black and white stripes at varying luminance levels) which were randomly displayed on the back of each chamber. Within 2 weeks of training, all rats were able to distinguish between these two visual patterns. The discrimination threshold of normal pigmented rats was a luminance level of -5.37+/-0.05 log cd/m(2); whereas the threshold level of 100-day-old RD rats was -1.14+/-0.09 log cd/m(2) with considerable variability in performance. When tested at a later age (about 150 days), the threshold level of RD rats was significantly increased (-0.82+/-0.09 log cd/m(2), p<0.03, paired t-test). This apparatus could be useful to train rats at a very early age to distinguish between two different visual stimuli and may be effective for visual functional evaluations following therapeutic interventions.
authors.affiliation: Department of Ophthalmology, Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. bthomas@doheny.org
authors.forename: Biju B
authors.initials: BB
authors.lastname: Thomas
authors.forename: Deedar M
authors.initials: DM
authors.lastname: Samant
authors.forename: Magdalene J
authors.initials: MJ
authors.lastname: Seiler
authors.forename: Robert B
authors.initials: RB
authors.lastname: Aramant
authors.forename: Sharzad
authors.initials: S
authors.lastname: Sheikholeslami
authors.forename: Kevin
authors.initials: K
authors.lastname: Zhang
authors.forename: Zhenhai
authors.initials: Z
authors.lastname: Chen
authors.forename: SriniVas R
authors.initials: SR
authors.lastname: Sadda
mesh_terms: D000375:Aging; D000818:Animals; D030801:Animals, Genetically Modified; D002755:Choice Behavior; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D009154:Mutation; D010775:Photic Stimulation; D051381:Rats; D012243:Rhodopsin / Q000235:genetics*; D014785:Vision, Ocular / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
chemical_list: D012243:Rhodopsin