Sex differences in the dendritic branching of dentate granule cells following differential experience.

Male and female hooded rats were raised from weaning in either a complex or an isolated environment in two separate replications. After one month, the brains were Golgi-Cox stained and dendritic fields of dentate gyrus granule cells were quantified. There was a sex difference in response to the environment. Females raised in the complex environment had more dendrite per neuron than females from the isolated environment in both replications. This difference was evident chiefly in the length of dendritic branches. Males showed few differences in response to the environments in either replication and, to the extent that there were differences, there was a slight tendency for isolated males to have more dendrite per neuron than males from the complex environment. In comparisons between the sexes within an environment, males had more dendritic material per neuron than females in the isolated environment while females had a larger dendritic tree than males in the complex environment. The above pattern of differences was not altered when hemisphere or location of the cell body within the granule cell layer were taken into account, although the shape of the dendritic tree varied with the cell's position in the layer in all groups. Thus, females show greater structural change in the dentate granule cells in response to these environments than do males.