Chronic nicotine intake alters human motor cortex excitability

Objective: Being the main addictive component of tobacco, nicotine is a widely used neuroactive substance. Various studies in animal models and in humans indicate that nicotine influences synaptic plasticity, resulting in functional and structural changes in motor cortex. The aim of the present study was to explore effects of chronic nicotine intake on human motor cortex excitability with transcranial magnetic stimulation (TMS). Methods: Thirty-eight right-handed volunteers, aged 20–30 years, were investigated in this study. Nineteen otherwise healthy chronic smokers were compared with nineteen sex-matched healt…