Learning and Memory Enhancement by Pemoline and Magnesium Hydroxide (PMH)

Abstract

Numerous reports in the literature indicate that there are discrete changes in the EEG during various phases of conditioning in animals [1]. Some of the most interesting series of studies on the subject were the ones correlating evoked-potential changes with behavioral conditioning. Thus, marked changes in amplitude of evoked-potential responses have been reported by numerous investigators when conditioned cues are paired with electric shock in behavioral conditioning. This form of EEG correlation with behavioral conditioning may be extremely useful in characterizing drug activity. At the same time, when the conditioning is an operant one, where the animal may prevent shock reinforcement by pressing a bar, the evoked response may diminish markedly. Perhaps this difference in evoked-potential response to instrumental operant conditioning, as compared with conditioning where shock cannot be prevented, could account for differences in extinction rates. Thus, the slow extinction rates in overtrained animals may have correlates in the diminution of the evoked response. In the more classical, nonoperant form of conditioning, where stimulus is paired with shock, the evoked potential increases in amplitude and is detectable in other areas.