The organization of basilar dendritic patterns in the CA1 hippocampal region obtained from 13 middle-aged and elderly human subjects was assessed using the Golgi method. Neurons were classified according to hemisphere of origin and the sex of the respective subjects. Three parameters were measured: total dendritic length (TDL), number of dendritic segments (NDS) and average segment length (ASL, which is TDL divided by NDS). Dendritic segments were classified into proximal (first to third order) and distal (fourth order and above). Sex differences were found in distal TDL and in proximal and distal NDS, neurons belonging to males having larger values than those belonging to females. In addition, a hemispheric difference was detected in distal TDL, in which neurons of the left hemisphere had larger values than those of the right hemisphere.
