THE EFFECTS OF TOBACCO SMOKING ON THE SHORT, MIDDLE, AND LONG-LATENCYRESPONSES OF THE BLINK REFLEX IN HUMANS

The three responses (R1, R2, and R3) of the electrically elicited blin k reflex (BR) obtained in four normal human subjects were investigated before and after smoking both a filtered and an unfiltered cigarette. The changes observed in the BR were stronger and statistically more s ignificant for the unfiltered than for the filtered cigarette, (p < 0. 0001) and mere more dramatic in R3 than R1 or R2. The action of nicoti ne on central pathways located at the interneuronal network of the bra instem, basal ganglia, and C fiber structures involved with this refle x seems to be the most likely mechanism for these findings.