[Hippocampal dimensions, memory and learning during rat ontogenesis].

Injury to the hippocamp disturbs learning processes and short-term memory in 20-, 50- and 110-day rats. In 50-day rats, hippocampectomy results in lesser changes in learning and memory than in 20- and 110-day animals. Anatomo-physiological characteristics of the hippocamp in 20-day rats presumably indicate a particular importance of this structure at early stages of ontogenesis, when the brain cortex is not yet sufficiently mature and its connections with other structures are not completely formed. Non-linear dependence of learning disturbance in rats of varying age after hippocampectomy suggests that in rat hippocampal function undergoes changes during individual development of animals.