Quantitative changes of dendrites in rat dentate gyrus and basal nucleus of Meynert after passive avoidance training in the neonatal period.

Quantitative morphological analysis of the number of granule cell dendritic spines, as well as total dendritic length and dendritic branching of neurons in the dentate gyrus and the nucleus of Meynert was done in 11-day-old rats after passive avoidance training in the neonatal period. Learning improved stepwise and its neuromorphological sequels were characterized by a statistically significant enhanced number of dendritic spines, due to an increase of thin spines, enhanced dendritic branching in both structures, and increased total dendritic length in the dentate gyrus compared with the controls.