The EEG effects of tobacco smoking--a review.

In summary, smoking does produce obvious changes in EEG activity. Human studies have been limited to surface electrodes. These have provided evidence of the alpha, evoked potential, and CNV effects of smoking. Changes in alpha and evoked potential activity have been statistically analyzed across subjects. These analyses indicated statistically significant arousal effects. However, large individual differences in responding were observed but not analyzed. Analysis of individual data in the Ashton, et. al. (1974) study indicated some arousal effects and some sedative effects, depending on the personality characteristics of the individual subject. Differential effects might have been detected in other studies had individual subject data been adequately analyzed. In research with nonhuman subjects, nicotine and tobacco smoke produced cortical arousal and sometimes a biphasic effect of arousal followed by apparent sedation. Behavioral effects accompanied the cortical arousal, including eyelid opening, head movements, and eye movements. During the synchronization phase, crouching, low mobility, and closed eyes occurred. Both the limbic and reticular activating systems seem to be affected by nicotine and smoking with the hippocampus most noticeably affected.