This project comprises morphological analyses of developing neurons grown in situ and in vitro. In the cerebellar cortex our investigations are aimed presently to elucidate the pattern of spin development of basket cells and also to determine the events that lead to the regression of spines which have been able to form successful synapses. The morphological studies of aggregates prepared from dissociated embryonic cells from various parts of the brain are intended to assess the developmental potential of young dissociated neurons reaggregated in vitro to express their basic phenotype and to establish neuronal connectivities. BIBLIOGRAPHIC REFERENCE: Larramendi, L.M.H. and M. Zevin. Synaptic contacts on transient spines of developing basquet cells in mouse cerebellum. Proc. IV. Panamerican Congress of Anatomy. Montreal (1975).