Aberrant callosal morphology in ex-smokers.

Abstract

Cigarette smoking is associated with widespread structural alterations in both brain hemispheres as well as of the corpus callosum (i.e., the brain's main interhemispheric white matter pathway). While similar hemispheric alterations have also been reported in ex-smokers, no study has yet examined the corpus callosum in ex-smokers. We compared callosal morphology in a sample of 107 ex-smokers (57 males/50 females) and 193 non-smokers (73 males/120 females), aged between 42 and 97 years. More specifically, we measured the total callosal area as well as seven callosal subregions using the Witelson parcellation scheme. At uncorrected levels, we detected significantly smaller callosal areas in ex-smokers than in non-smokers within the posterior midbody, genu, and isthmus (albeit the latter only on a trend level). When applying corrections for multiple comparisons, only the effect within the posterior midbody remained significant. Our findings suggest a weaker interhemispheric connectivity in ex-smokers compared to non-smokers, specifically between frontal and temporal areas.