[Brain central amygdaloid nucleus: cytoarchitechtonics, neuronal organization, connections]

This review describes different aspects of structural and functional organization of amygdaloid central nucleus (CN) in association with the findings indicating its involvement in the development of stress reactions and adaptive behavior in animals. The data on the distribution of neuropeptides, neurotransmitters and neuromodulators in CN are discussed. It is emphasized that CN appears at the earliest stages of amygdaloid formation, undergoes remodeling together with it and reflects the evolution of the whole amygdaloid. The detailed data are presented on the cytoarchitectonic of amygdaloid CN, its heteromorphism and subdivision into zones (subnuclei), based on the different methods of investigation and evaluation criteria. The neuronal organization of CN and its subnuclei is discussed, and the detailed description of neurons of different types is given according to their topography, cell body dimensions and shape, dendrite orientation and branching pattern, organization of spine apparatus and axon structure. The developmental features of amygdaloid CN in mammalian animal and human ontogenesis are considered. The analysis covering the literature data and the results of authors' own investigations indicates that CN functions not only as intraamigdaloid integrative center, but also as one of the major channels providing both afferent and efferent connections of amygdaloid with other brain structures.