Changing Thought and Action in Tobacco Dependence With Transcranial Magnetic Stimulation

Tobacco use is the greatest cause of preventable death in the US and cigarette smokers
exhibit substantial relapse following treatment. Understanding the brain mechanisms involved
in tobacco dependence is an important step toward reducing the high rate of relapse
associated with current behavioral and pharmacological treatments for smoking cessation.
This study seeks to examine the effects of high frequency, repetitive Transcranial Magnetic
Stimulation (rTMS) on decision-making and smoking behavior. A concept central to this study
is that "quitting" tobacco necessitates making conscious choices not to smoke (to delay
gratification) and these choices are influenced by the balance of activity between the
fronto-parietal systems that process the value of rewards and limbic systems that are
involved with immediate gratification. We aim to: 1) determine how two different levels of
cortical excitation (10 Hz and 20Hz), induced by different rTMS frequencies, influence
reward and risk-taking choices and cigarette consumption. Additionally, we aim to 2)
determine how limbic activation due to acute nicotine withdrawal and/or satiation modifies
the effects in aim 1. Twenty non-smoking and 20 smoking participants will receive two levels
of high frequency rTMS and comparable sham stimulation (using electrical scalp stimulation)
delivered over the left prefrontal cortex. Smokers will also crossover between nicotine
satiation and acute withdrawal conditions to determine how rTMS interacts with limbic
activation associated with nicotine use and withdrawal. In addition, changes in
preattentional (brainstem-thalamus processing as measured using the P50 midlatency auditory
evoked potential) and attentional (thalamocortical processing as measured using the
Psychomotor Vigilance Task; PVT) will be assessed before and after treatment to
quantitatively determine changes in preattentional/arousal and attentional function.