The effect of nicotine patches on the neural activity in the reward circuit of smokers: an fMRI study with visual stimulation

Introduction: The purpose of this study was to investigate the effect
of nicotine patches (NP) on cognitive processes linked to cigarette
addiction and craving.
Materials and Methods: An fMRI experiment (3T, Achieva, Philips)
was performed on five healthy volunteers (age 18–26 years; 1 male, 4
females) with smoking addiction (FTND C 4) in four random conditions
and 1-week interscan interval: regular smoking (S); smoking
deprivation for 14 h (SD) prior to the scan; smoking deprivation for
14 h combined with a 21 mg nicotine patch (SD + NP); and smoking
deprivation for 14 h combined with a 0 mg placebo patch (SD + PP).
Visual stimulation was provoked in block design by randomly displaying
42 images of smoking related scenes alternating with neutral
images. First and second level analysis was performed for image
processing. ANOVA was used to compare average group activations
between conditions. Results were also compared to a non-smoking
control group (N = 5). The standard Questionnaire for Smoking
Urges (QSU) on a 7-point scale was simultaneously obtained immediately
before and after each scan. Non-smokers were compared to
smokers in all conditions.
Cases: The QSU showed that craving significantly increased from
1.63 ± 1.01 in the S condition to 3.34 ± 1.94 after performing the
experimental fMRI scan. Between conditions, only significant differences
were seen when comparing SD (5.59 ± 1.33) with S
(1.63 ± 1.01) or SD + NP (2.52 ± 1.23). The fMRI imaging results showed frontal and limbic activation in non-smokers when comparing
to all conditions in smokers. During the S condition, significant
activation was seen in the limbic system, attention areas and frontal
regions compared to SD + NP, SD + PP and SD. In the SD + NP
condition, limbic circuit and attention area were activated compared
to SD and SD + PP. The SD + PP and SD condition showed activation
in different areas of the frontal cortex and limbic system
compared to S, SD + NP conditions.
Discussion: The QSU showed a significant difference between SD
condition and when nicotine is present (S and SD + NP), and thus
nicotine reduced craving. The fMRI experiment revealed lower
activity in areas associated with attention when nicotine lacks
(SD + PP and SD). In line with the QSU results, areas involved with
craving showed less activity when nicotine is present (S and
SD + NP).
References:
Menossi HS, Goudriaan AE, Azevedo-Marques Pe´rico C, de Andrade
AG, D’Elia G, Li CS, Castaldelli-Maia JM. (2013) Neural bases of
pharmacological treatment of nicotine dependence—insights
from functional brain imaging: a systematic review. CNS Drugs;
27(11): 921–941.

Publication year:2015