The relationship of dendritic branching complexity to ontogeny and cortical connectivity in the pyramidal cells of the monkey amygdala: a Golgi study.

A quantitative analysis of the dendritic branching complexity of pyramidal cells in the small pyramidal celled divisions of the monkey amygdala reveals a systematic variation among the divisions. This variation provides a basis for the identification and differentiation of the divisions in the Golgi impregnated rhesus monkey amygdala. The order of increasing dendritic branching complexity of the divisions under consideration is as follows: cortical nucleus, medial basal nucleus, parvocellular accessory basal nucleus and ventromedial portion of lateral nucleus, and dorsolateral portion of the lateral nucleus. The order of these divisions in terms of their dendritic branching complexity bears a direct relationship to their ontogenetic developmental sequence and to their progressive transition in connectivity from allocortical to more highly evolved isocortical input.