Reduced thickness of medial orbitofrontal cortex in smokers.
BACKGROUND
Structural deficiencies within the prefrontal cortex might be related to drug-taking behavior that prevails in smokers. Cortical thickness has been found to be a structural modulator of cerebral function and cognition and a subtle correlate of mental disorders. However, to date an analysis of cortical thickness in smokers compared with never-smokers has not been undertaken.


METHODS
We acquired high-resolution magnetic resonance imaging scans from 22 smokers and 21 never-smokers and used FreeSurfer to model the gray-white and pial surfaces for each individual cortex to compute the distance between these surfaces to obtain a measure of cortical thickness. The main cortical folds were aligned across individuals with FreeSurfer's surface-based averaging technique to compare whole brain differences in cortical thickness between smokers and never-smokers.


RESULTS
Relative to never-smokers, smokers showed greater cortical thinning in the left medial orbitofrontal cortex (mOFC). Cortical thickness measures extracted from mOFC correlated negatively with the amount of cigarettes consumed/day and the magnitude of lifetime exposure to tobacco smoke.


CONCLUSIONS
The brains of smokers are structurally different from those of never-smokers in a dose-dependent manner. The cortical thinning in mOFC in smokers relative to never-smokers might imply dysfunctions of the brain's reward, impulse control, and decision-making circuits. Related behavioral correlates are suggested to be relevant for smoking initiation and maintenance.
Kühn
Simone
S
Faculty of Psychology and Educational Sciences, Department of Experimental Psychology, Ghent University, Ghent, Belgium. simone.kuhn@ugent.be
Schubert
Florian
F
Gallinat
Jürgen
J
D000328:Adult; D001284:Atrophy / Q000473:pathology; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D012907:Smoking / Q000473:pathology*