Alterations in interhemispheric functional and anatomical connectivity are associated with tobacco smoking in humans

Abstract

Abnormal interhemispheric functional connectivity correlates with several neurologic and psychiatric conditions, including depression, obsessive-compulsive disorder, schizophrenia, and stroke. Abnormal interhemispheric functional connectivity also correlates with abuse of cannabis and cocaine. In the current report, we evaluated whether tobacco abuse (i.e., cigarette smoking) is associated with altered interhemispheric connectivity. To that end, we examined resting state functional connectivity (RSFC) using magnetic resonance imaging (MRI) in short term tobacco deprived and smoking as usual tobacco smokers, and in non-smoker controls. Additionally, we compared diffusion tensor imaging (DTI) in the same subjects to study differences in white matter. The data reveal a significant increase in interhemispheric functional connectivity in sated tobacco smokers when compared to controls. This difference was larger in frontal regions, and was positively correlated with the average number of cigarettes smoked per day. In addition, we found a negative correlation between the number of DTI streamlines in the genual corpus callosum and the number of cigarettes smoked per day. Taken together, our results implicate changes in interhemispheric functional and anatomical connectivity in current cigarette smokers.

White matter development and tobacco smoking in young adults: A systematic review with recommendations for future research

“…These findings are contrary to those from most adult studies (Savjani et al, 2014; Lin et al, 2013; Umene-Nakano et al, 2014; Viswanath et al, 2015), highlighting the importance of assessing relationships with white matter across different developmental epochs. Below several other important areas for future research in this area are highlighted.…”

“…These findings are opposite to those from most studies of adults (Lin et al, 2013; Savjani et al, 2014; Umene-Nakano et al, 2014; Viswanath et al, 2015), raising the possibility that the relationship between white-matter structures and tobacco smoking may differ across the lifespan. However, no previous studies have controlled for the effects of acute nicotine on DTI indices, nor have they assessed possible effects of pubertal stage and alternative nicotine administration methods (e.g., hookahs, e-cigarettes).…”

“…While increased FA values within the corpus callosum and other tracts have been reported in some studies of adult smokers (Paul et al, 2008; Hudkins et al, 2012), decreased FA values are more commonly reported in the same regions (Lin et al, 2013; Savjani et al, 2014; Umene-Nakano et al, 2014; Viswanath et al, 2015). Taken together, this suggests that the relationship between FA values and tobacco use may differ between early versus middle adulthood, although other possibilities (acute versus chronic effects of smoking, cohort effects) cannot be excluded.…”

Resting‐state functional connectivity and nicotine addiction: prospects for biomarker development

“…In smokers, the administration of acute nicotine enhances functional connectivity between the two brain hemispheres, and more specifically in rostral as opposed to caudal regions . This enhanced interhemispheric connectivity is observed only in smokers after ad lib smoking.…”

Neuroplasticity and MRI: A perfect match

“…(drug) addiction (Fowler, Volkow et al 2007, Parvaz, Alia-Klein et al 2011, Salo and Fassbender 2012, Moulton, Elman et al 2014, Viswanath, Velasquez et al 2015 and aging (Lockhart and DeCarli 2014) on the brain have been evaluated thoroughly.…”