title: The dendritic morphology of pyramidal neurons in the rat hippocampal CA3 area. I. Cell types.
abstract: Pyramidal neurons from the hippocampal CA3 area of hooded rats were qualitatively and quantitatively described from Golgi-stained tissue. The most numerous of the pyramidal neurons, those with a single apical shaft, fell into two major categories. One category, termed short-shaft pyramidal neurons, is characterized by short apical shafts, a large number of thorny excrescences, and densely branched apical and basilar trees. The second category, long-shaft pyramidal neurons, is characterized by a long apical shaft, a small number of thorny excrescences and relatively less dendritic branching in both the apical and basilar trees. The somata of short-shaft pyramidal neurons tend to be located higher in stratum pyramidale than the somata of long-shaft neurons. Quantitative measurements, which included both analysis of dendritic branching and the distribution of dendritic material sampled at 10% intervals from the cell body, confirmed the qualitative observation that short-shaft neurons had more total dendritic length than long-shaft neurons. The difference in the total dendritic length observed between long- and short-shaft pyramidal neurons could be an indication that each type receives a different number of synapses per neuron. The less commonly observed variants of pyramidal neurons were briefly described but not quantified. This study demonstrates that CA3 pyramidal neurons are not a homogeneous group but that their heterogeneous characteristics fall into two major categories.
authors: Department of Psychology, University of Illinois, Champaign 61820.
authors: J M
authors: JM
authors: Fitch
authors: J M
authors: JM
authors: Juraska
authors: L W
authors: LW
authors: Washington
mesh_terms: D000818:Animals; D002452:Cell Count; D003712:Dendrites / Q000648:ultrastructure*; D005260:Female; D006624:Hippocampus / Q000166:cytology*; D008297:Male; D009474:Neurons / Q000145:classification / Q000166:cytology*; D051381:Rats; D012834:Silver; D013194:Staining and Labeling
chemical_list: D012834:Silver