Dendritic structure of single hippocampal neurons according to sex and hemisphere of origin in middle-aged and elderly human subjects

The organization of basilar dendritic patterns in the CA1 hippocampal regio n obtained from 13 middled-aged and elderly human subjects was assessed usi ng the Golgi method. Neurons were classified according to hemisphere of ori gin and the sex of the respective subjects. Three parameters were measured: total dendritic length (TDL), number of dendritic segments (NDS) and avera ge segment length (ASL, which is TDL divided by NDS). Dendritic segments we re classified into proximal (first to third order) and distal (fourth order and above). Sex differences were found in distal TDL and in proximal and d istal NDS, neurons belonging to males having larger values than those belon ging to females. In addition, a hemispheric difference was detected in dist al TDL, in which neurons of the Left hemisphere had larger values than thos e of the right hemisphere. (C) 2001 Elsevier Science B.V. All rights reserv ed.