[Parameters of the reflex responses of cat spinal cord neurons during ontogenesis]

In acute experiments on immobilized "spinal" 1-68 days old kittens and adult cats, extracellular recordings of action potentials (AP) in lumbar interneurons have been made during afferent or antidromic stimulation with different frequency. It was shown that variation coefficient of the number of AP in a response reliably decreases with the age of the animals, as well as during the decrease of stimulation frequency and the increase of the mean frequency of the background activity. More complex changes were found in the distribution asymmetry of the number of AP, whereas changes in the excess of the distribution were found to be insignificant. Possible physiological mechanisms of the observed dynamics are discussed.