Experiments are reported in which a conditioned response to the sound of a bell was established in 18 male rats. This response was then inhibited by lack of reenforcement with the unconditioned stimulus. Although control experiments showed that conditioned responses thus inhibited do not recover spontaneously it was found that the application of one or more metrazol convulsions or of electrically induced convulsions restored temporarily the inhibited conditioned response. The experimentally proved removal of inhibition by "shock treatment" is of interest in view of the effects of the shock treatment in psychoses.Abstract Teaser