Behavioral evaluation of visual function of rats using a visual discrimination apparatus

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.

[1]  I. Jackson,et al.  Presence of visual head tracking differentiates normal sighted from retinal degenerate mice , 2002, Neuroscience Letters.

[2]  M. Cerro,et al.  Correlates of Photoreceptor Rescue by Transplantation of Human Fetal RPE in the RCS Rat , 1998, Experimental Neurology.

[3]  M. Lavail,et al.  Variability in rate of cone degeneration in the retinal degeneration (rd/rd) mouse. , 1997, Experimental eye research.

[4]  S. Sadda,et al.  Optokinetic test to evaluate visual acuity of each eye independently , 2003, Journal of Neuroscience Methods.

[5]  W. Precht,et al.  Functional deficits in the optokinetic system of albino rats , 1979, Experimental Brain Research.

[6]  M. McCall,et al.  Retinal transplantation-induced recovery of retinotectal visual function in a rodent model of retinitis pigmentosa. , 2003, Investigative ophthalmology & visual science.

[7]  A. Laties,et al.  Activation of Caspase-3 in the Retina of Transgenic Rats with the Rhodopsin Mutation S334ter during Photoreceptor Degeneration , 1999, The Journal of Neuroscience.

[8]  R. Lund,et al.  Photoreceptor Layer Reconstruction in a Rodent Model of Retinal Degeneration , 1999, Experimental Neurology.

[9]  R. Lund,et al.  Long-term preservation of cortically dependent visual function in RCS rats by transplantation , 2002, Nature Neuroscience.

[10]  R. Lund,et al.  Cell Transplantation as a Treatment for Retinal Disease , 2001, Progress in Retinal and Eye Research.

[11]  S. Sadda,et al.  Light response differences in the superior colliculus of albino and pigmented rats , 2005, Neuroscience Letters.

[12]  J. Juraska,et al.  Vernier and grating acuity in adult hooded rats: the influence of sex. , 1997, Behavioral neuroscience.

[13]  R. Douglas,et al.  Behavioral assessment of visual acuity in mice and rats , 2000, Vision Research.

[14]  M. Seeliger,et al.  Grating acuity at different luminances in wild-type mice and in mice lacking rod or cone function. , 2005, Investigative ophthalmology & visual science.

[15]  R. Lund,et al.  Sensory capacity of the royal college of surgeons rat. , 2000, Investigative ophthalmology & visual science.

[16]  R M Douglas,et al.  Independent visual threshold measurements in the two eyes of freely moving rats and mice using a virtual-reality optokinetic system , 2005, Visual Neuroscience.

[17]  D. Diloreto,et al.  Neither intraocular grafts of retinal cell homogenates nor live non-retinal neurons produce behavioral recovery in rats with light-damaged retinas. , 1995, Cell transplantation.

[18]  I. Whishaw,et al.  Variation in visual acuity within pigmented, and between pigmented and albino rat strains , 2002, Behavioural Brain Research.

[19]  M. McCall,et al.  Retinal transplants restore visually evoked responses in rats with photoreceptor degeneration. , 2001, Investigative ophthalmology & visual science.

[20]  A. Cowey,et al.  The retinal origin of uncrossed optic nerve fibres in rats and their role in visual discrimination , 1979, Experimental Brain Research.

[21]  W. Muntz.  A behavioural study on photopic and scotopic vision in the hooded rat. , 1967, Vision research.

[22]  SriniVas R Sadda,et al.  Superior colliculus responses to light - preserved by transplantation in a slow degeneration rat model. , 2004, Experimental eye research.

[23]  S. Sadda,et al.  Retinal transplantation. A treatment strategy for retinal degenerative diseases. , 2006, Advances in experimental medicine and biology.