Synaptic development of the cerebral cortex: implications for learning, memory, and mental illness

This chapter explores various questions: Are synapses added as we learn? Are there more synapses in some cortical areas than in others? Are there gender differences in synaptic density and do we lose synapses as we age? If we lose synapses with age, what is the timing and rate of this dissolution? To address these issue this chapter present the finding reported in the rhesus monkey. The study of major structural and functional subdivisions of the cortex over the primate lifespan offers a particularly comprehensive view of synapse formation. From study, it is eminently clear that knowledge of the normal course and mechanisms of synapse formation, the influence of various exogenous and endogenous events upon synapse stability and turnover, are essential prerequisites to determining the locus and timing of etiological factors in diseases that affect the cortex and alter cognitive function.