PHOTOPERIOD-TEMPERATURE AND NEUROBLAST PROLIFERATION-MIGRATION IN THEADULT LIZARD CORTEX

THE lizard medial cortex (a zone homologous to the mammalian fascia de ntata) shows delayed postnatal neurogenesis throughout the lifetime of these animals. Experimental lesioning of this area is followed by neu ronal regeneration, a unique phenomenon in the adult amniote telenceph alon. The differential effects of temperature and photoperiod on postn atal neurogenetic activity mere studied using tritiated thymidine puls es and posterior autoradiography as well as proliferating cell nuclear antigen (PCNA) immunostaining. Long (summer) photoperiods increased t he number of proliferating neuroblasts in the ependymal neuroepitheliu m. Cold (winter) temperature prevented migration of the newly generate d immature neurones.