“…In some neuronal systems, removal of afferent inputs curtails the very survival of postsynaptic cells in the course of normal development (Oppenheim, 198 1;Okado and Oppenheim, 1984;Clarke, 1985). Nevertheless, the absence of afferent input has little influence on the dendritic differentiation of spinal neurons (Brown et al, 1983;Sedivec et al, 1986;see, however, Brown et al, 1979) or of sympathetic ganglion cells (Hamlyn, 1954;McLachlan, 1974;Smolen and BeastonWimmer, 1986;Voyvodic, 1987) (although afferent input is necessary for the biochemical differentiation of sympathetic ganglion cells; see Black, 1978Black, , 1982. Therefore, it is quite unlikely that axotomy of the superior cervical ganglion first induces a loss of afferent synapses, which then results in a secondary dendritic atrophy.…”