Effects of strychnine sulphate on classically conditioned nictitating membrane responses of rabbits.

3 experiments'were conducted to determine effects of strychnine sulphate on classically conditioned nictitating membrane responses of rabbits. Facilitation of response acquisition by presession injections of strychnine was attributed to a simple performance effect because Ss pretreated with strychnine demonstrated a higher level of CRs following unpaired CS-US presentations. Depression of conditioning by postsession injections of strychnine sulphate may be related to the nature of the postinjection environment. The purpose of the present investigations was to determine the effects of a CNS excitant, strychnine sulphate, on the acquisition of the classically conditioned nictitating membrane response of the rabbit. While the effects of strychnine sulphate on a variety of instrumental approach and avoidance responses have been reported, there is only one recently published study examining the effects of this drug on a classically conditioned defensive response (Benevento & Kandel, 1967).