Cognitive training increases dendritic arborization in the dorsal hippocampal CA1 and CA3 neurons of female and male Long-Evans rats

Experiences influence the development of the central nervous system. Cognitive training promotes changes in the structure of the brain, such as in its weight and number of cells, as well as ability to perform dendritic remodeling. The present study was designed to detect possible differences in the neuronal morphology of the dorsal hippocampus between female and male Long-Evans rats after cognitive training (CT). CT was promoted through three learning and memory tests: the Morris water maze, the Barnes circular maze, and Novel object recognition tests. Our data revealed no differences in learning or memory capacities between female and male rats; rats of the two sexes solved the behavioral test with equal efficiency. CT caused an increase in the basilar and apical dendritic arborization of CA1 neurons in male rats, whereas female rats that underwent CT presented only remodeling in the apical arbors of CA1 neurons. The basilar arbors of CA3 neurons of female rats showed an increase in arborization, but their apical arbors were not modified; the arbors of CA3 neurons of male rats submitted to CT were not modified. Total dendritic length was modified by CT in the apical arbors of CA1 neurons of female and male rats and in the basilar CA1 arbors of male rats. There was a significant increase in dendritic spine density in all arbors of CA1 and CA3 neurons of females and males subjected to CT. These results suggest that dendritic remodeling after CT is similar between female and male rats.