This study will examine the effects of high frequency, repetitive Transcranial Magnetic Stimulation (rTMS) on decision-making and smoking behavior.
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 frontal-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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
66
All participants will receive 90 10-pulse trains of 1 sec duration with an interval of 20 seconds. Smokers will receive the treatment twice, once in a nicotine-satiated condition, and once in a nicotine-withdrawal condition.
All participants will receive 45 20-pulse trains of 1 second duration with an interval of 20 seconds. Smokers will receive the treatment twice, once in a nicotine-satiated condition, and once in a nicotine-withdrawal condition.
University of Arkansas for Medical Sciences
Little Rock, Arkansas, United States
A Difference Score for the Log Value of K.
K is a output value, a summary statistic, derived from a hyperbolic function that summarizes the rate at which monetary values are discounted according to the time they are received. The value of K can either increase or decrease from its baseline value. For example, an increase in K would indicate that the participant is choosing to receive larger amounts of money at a later point in time. A decrease would suggest the opposite - lesser amounts of money at an earlier point in time). The difference score is calculated from baseline to that immediately after 10 or 20 Hz rTMS.
Time frame: baseline and immediately after stimulation, an average of 25 seconds.
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The look and sound of active rTMS is reproduced with the same coil used in the active conditions. The magnetic field in the sham coil is markedly attenuated at only 5% of stimulator output. The feel of active stimulation will be reproduced by delivering monophasic current pulses to the left, frontalis muscle with a Isolated Stimulator and two carbon rubber electrodes. Smokers will receive Sham rTMS in both the nicotine-satiated and nicotine-withdrawal conditions.