Raising rabbits in a moving visual environment: an attempt to modify directional sensitivity in the retina

Abstract

1. Rabbits were raised inside drums with vertical stripes painted on the inside. The rabbits were held stationary while the drum rotated continually around them: rotation was always in the same direction for any one animal. Rabbits in one litter were put in the drum for 15 min/day from 10-15 days after birth to about 60 days after birth, with the drum rotating to the right. Rabbits in another litter were put in for 15 min/day with the drum moving left. Rabbits in three other litters were put in for 2-3 hr/day with the drum moving right. All rabbits were kept in the dark when not in the drum.2. Optokinetic nystagmus was measured by photographing eye movements during drum rotation at various stages of development. The response to rotation in both directions was measured in a few adult animals. Only small differences were found in the adult animals between optokinetic nystagmus in response to a drum moving right compared to a drum moving left.3. Recordings were made from ganglion cells in the retina and their receptive fields were mapped. A total of 607 cells from deprived rabbits were analysed. The percentages of on-centre and off-centre centre-surround types, on-off directionally sensitive types, and on-directionally sensitive types were not significantly different from normal.4. The percentages of directionally sensitive cells responding in the anterior, posterior, superior and inferior directions were normal. The fall-off in sensitivity for these cells with change in direction from the preferred direction was normal.5. A few orientation sensitive cells were found responding to horizontally oriented bars.6. We conclude that this selective deprivation of rabbits had little effect on the optokinetic response and no effect on the organization of the retina.