Effect of cerebellar granule cell depletion on spatial learning and memory and in an avoidance conditioning task:...

Rats of the DA/HAN strain (pigmented rats) were submitted to two experimental tasks consisting in spatial learning (water escape experiment) and in passive avoidance conditioning. These rats were either totally or partially deprived of their granule cells using two different schedules of postnatal X-irradiation of the cerebellum. When they were 3 months old, the animals were submitted to an initial learning session, followed by a retrieval test seven days later. The scores of the rats which were partially deprived of granule cells appeared similar to those of controls, except for a mild deficiency of spatial learning. The learning and retrieval scores of the rats totally deprived of granule cells were similar to those of controls at the passive avoidance conditioning task, but these animals were unable to accurately learn a spatial task and showed memory impairments relative to controls. These results are discussed in terms of cognitive defects.