Studies on the structure and function of avian circumventricular organs in vitro (choroid plexus, glycogen body, pineal organ). The walls of the ventricular system in the brain show regional specializations termed circumventricular organs. Despite the fact that these organs have been sufficiently described morphologically, a convincing functional concept is lacking, especially in rela- tion to adjacent nervous centers and to the cerebrospinal fluid. In vitro experimenta- tion allows isolated analysis of circumventricular organs without interaction of other neuronal or humoral influences....