On the 24-hour periodicity of conditioned reflex activity in chickens

Summary

The 24-hour rhythm of the conditioned reflex activity was studied in Leghorns. The value of conditioned reflexes was determined every 4 hours to the positive and negative (alternating during the experiment) color monochromatic stimulants. The motor food method was used. The deepness of the successive inhibition and the rapidity of formation of extinguishing inhibition during the morning and evening hours was determined in other series of experiments. The presence of 24-hour rhythm of conditioned reflex activity of chickens was established. The most pronounced decrease in the conditioned reflex activity of chickens occurs from midnight to 4 o'clock in the morning. The successive inhibition is enhanced in the evening, while the development of the extinguishing inhibition is delayed.