FLEXIBLE EFFECTS OF QUANTIFIED CIGARETTE-SMOKE DELIVERY ON EEG DIMENSIONAL COMPLEXITY

A quantified smoke delivery system (QSDS) was used to experimentally c ontrol the administration of inhaled cigarette smoke to 28 male smoker s. One puff (2 s, 35 cc) was taken every 30 s on a cigarette (nicotine yield 1.0 mg) until the char line reached 3 mm from the filter wrap. The smoke was inhaled for 5 s. Resting eyes-closed and eyes-open EEG w as recorded from F3, F4, P3, and P4 before and after quantified smoke delivery (QSD). EEG dimensional complexity (DCx, a measure derived fro m chaos theory) was computed using the Takens-Ellner method. QSD appea red to have a 'flexible' effect on EEG DCx, primarily lowering it in s ubjects whose pre-smoking level was high, not affecting it in subjects whose pre-smoking level was intermediate, and tending to raise it in subjects whose pre-smoking level was low. This replicates previous res ults obtained with ad libitum smoking, suggesting the hypothesis that smoking may have an ''optimizing'' effect on the complexity of brain d ynamics.