Persistent dysfunctional frontal lobe activation in former smokers

Objective: Chronic smoking and nicotine exposure are accompanied by impaired cognitive task performance, modulated cerebral activity in brain imaging studies, and neuritic damage in experimental animals. The profile of the described dysfunctions matches frontal lobe circuits which also play a role in reward processing and reinforcement behavior. However, it is largely unknown if cerebral dysfunctions are reversible or persist during long term abstinence. Materials and methods: Cortical activation during auditory target processing (oddball task, P300 component) was recorded with 32-channel EEG in 247 healthy subjects consisting of 84 smokers, 53 former smokers ( mean time of abstinence 11.9 years), and 110 never smokers. Results: Both current smokers and former smokers exhibited significantly diminished P300 amplitudes (Cz, Pz) relative to never smokers. Neuroelectric source analysis ( low resolution brain electromagnetic tomography) revealed a hypoactivation of the anterior cingulate, orbitofrontal, and prefrontal cortex in smokers compared to never smokers. A similar profile of hypoactivation was observed in former smokers. Conclusion: For the first time, evidence is provided that dysfunctional activation of frontal lobe networks in smokers is also present in long term abstainers.