Behavioral and electrophysiological consequences of cycloheximide administration in chick embryos

The effect of cycloheximide administration upon the spontaneous motility, electroencephalogram (EEG) and infra slow potential oscillations (ISPO) of brain hemispheres and upon the tectal optic evoked responses was investigated in 15-day- and 20-day-old chick embryos. Cycloheximide evoked in 15-day-old embryos, within some hours after systemic administration, a full depression of EEG activity and an apparent inhibition of spontaneous motility. The ISPO's of brain hemispheres remained unchanged during the entire investigation period. The inhibitory effect of cycloheximide was manifested in 20-day-old embryos by a high degree of ISPO depression only, whereas the EEG activity, optic evoked responses and spontaneous motility did not change. The information collected suggested that the different types of electrical activity generated in the brain at different stages of development were in different relationship to the normal proteosynthesis in embryonic brain tissue.