[Quantitative and comparative research or lamina V-pyramidal neurons in the regio retrosplenialis granularis in the rat].

Large pyramidal neurons of lamina V of regio retrosplenialis granularis and regio cingularis anterior of adult male rats were analyzed quantitatively and compared statistically. In both regions, these pyramids showed nearly equal values for their apical and basal dendritic tree, which is typical for pyramidal neurons in intermediate cortices. In important quantitative parameters the large pyramidal neurons of the both regions were comparable. The total spine number per neuron was in the same range for the pyramidal neurons in both cortical regions, whereby the smaller dendritic tree of retrosplenial pyramids showed a higher spine density in comparison with the larger cingulate pyramids. This fact indicates a nearly equal number of synaptic spine contacts with incoming afferents for both cell types. Therefore, both regions are considered to belong to the intermediate cortex-formation "mesoneocortex".