A genetic and molecular study of learning processes in rats.

Using the conditioned feeding reflex model, a polymorphism for the rate of formation of this response was identified in a population of laboratory animals. Selection for high and low rate of the formation of this reflex resulted in significant differences in this character between two strains by the second generation. These differences were maintained in subsequent generations. Heterogeneity for the rate of the formation of conditioned response in the population is shown to be genetically determined. The RNA-dependent DNA-polymerase activity in the hippocampus of fast-learning rats exceeds twofold that in slow-learning rats, while the rates of the DNA-dependent DNA-polymerase activities are similar. A significant increase in RNA-dependent DNA-polymerase only was found in the hippocampus of rats 20 min after training for the conditioned food response before the trace consolidation registered 40 min after the training session.