NO EFFECT OF CIGARETTE-SMOKING ON ELECTROENCEPHALOGRAPHIC NONLINEARITY

The Gaussian surrogate-date procedure was applied to the measurement o f the effect of cigarette smoking on the dimensional complexity of nor mal, resting EEG. Evidence of significant nonlinearity in the EEG was obtained, replicating previous results. However, unlike EEG dimensiona l complexity, EEG nonlinearity (difference between original and surrog ate data) was not affected by smoking. This indicates that, under rest ing conditions, smoking/nicotine may have a modulating effect on input from the reticular activating system, with such input having a global , linearizing effect on cortical dynamics. Nonlinear dynamics resultin g from intracortical processes appear not to be affected.