Lateralization of spike and wave complexes produced by hallucinogenic compounds in the cat

The ability of four hallucinogenic compounds--ketamine, phencyclidine, quipazine, and SKF-10 047--to produce some specific electrical pattern in portions of the limbic system and the hemispheric lateralization of such effects were studied in cats with permanently implanted electrodes. Electronic frequency and area integrators were used to analyze the results, and the percentage change in electrographic alterations was calculated. All compounds studied produced trains of spike and wave complexes in the cingulum, rapid discharges in the amygdala complex, and slow-wave synchronous activity in the septal nucleus. Those changes predominated in the left hemisphere. At small but hallucinatory concentrations of these drugs, the cortical EEG was not affected. Exploratory movements directed toward nonexistent objects, classified as hallucinatory-like behavior, appeared simultaneous with these changes in the EEG recordings. We concluded that there could exist a relationship between the appearance of spike and wave complexes in the limbic system without epileptic signs (twitching or myoclonus) and the presence of hallucinations, and that there is a left side hemispheric lateralization of the electrographic effects, viewing cerebral dominance phenomena as a functional and fluctuating state.