EVOLUTION OF SOME ELECTRICAL SIGNS OF CONDITIONING. PART I. NORMAL CAT AND RABBIT

Abstract

A study of the electrical signs of conditioning of cerebral rhythms was undertaken in normal cats and rabbits. Several forms of conditioned electrocortical responses were observed and appeared in a characteristic time sequence. Initially the conditioned stimulus produced no effect and the unconditioned stimulus a typical "driving". As more conditioning trials were presented, a generalized activation pattern appeared in response to the tone. Shortly after this an after-discharge to the flickered light was noted and then gradually the conditioned repetitive response was observed. This was usually transitory and after several trials was replaced by a persistent localized activation pattern. During the period of repetitive discharge, an evoked potential to the tone made its appearance. This was more durable than the repetitive response and tended to persist throughout the remainder of conditioning trials so that the final complex generally included both evoked potential and localized blocking. Modifying factors such as sleep, barbiturates and curare produced considerable variation in this sequence.