Spinal-cord concussion in frogs a study of reflex changes

A reliable experimental model of the spinal frog, employing the flexor withdrawal reflex to a noxious stimulus, has been used to study the response to single and repeated concussing blows over the spinal column. It is evident that caudally placed blows depress the reflex response, whereas more cephalad blows facilitate the response. The results of studies using repeated concussing blows support the concept that neuronal units may completely lose their function without suffering permanent structural damage.