Abstract: | Studies have been made on the properties of neuronal populations of the dorsal hyperstriatum of the forebrain in hens beginning from the 18th day incubation up to the 7th day after hatching, which were incubated and kept either in darkness or under periodic illumination. Among the investigated parameters of multicellular activity, mean frequency of the discharge activity was found to be most susceptible to the level of external light afferentation in ontogenesis. The discharge activity was more intense in the left hemisphere of chick embryos and chicks from illuminated group, which may be associated with asymmetrical visual afferentation resulting from embryonic position within the egg, and its modulating effect on synchronization processes in the adjacent neurones of the given structure. |