Visual sensitivity to orientation of rectangles in mice with retinal degeneration.

C3H/HeJ male mice, an inbred strain showing retinal degeneration (rd), and normal-eyed DBA/IJ male mice were studied in a task requiring discrimination of horizontally and vertically oriented rectangles. The apparatus was modified Yerkes discrimination apparatus. The mice were given 30 days of discrimination training, 10 trials/day, after which 10 more trails were given on the 31st day with positive and negative cues reversed. Both strains showed a highly significant decrease in errors during acquisition, the rd strain making significantly fewer errors than the DBA/IJ animals. Reversal of the cues brought about a sharp increase in percentage of errors.