title: Factors underlying prefrontal and insula structural alterations in smokers.
abstract: Based upon previous reports of alterations in white matter integrity and gray matter density in smokers, we examined these markers in a large, well-matched sample of smokers and non-smokers. We further investigated the effect of heavy cigarette exposure by using pack-years and the effects of two relatively stable, highly heritable traits in smokers (Fagerström Test of Nicotine Dependence (FTND), a measure of severity of nicotine dependence and Toronto Alexithymia Scale (TAS-20), a stable personality trait related to smoking). Forty-eight nicotine-dependent subjects and 48 matched controls were included in the analyses, with smokers also subdivided into high/low dependence and high/low pack-years smokers. White matter integrity (fractional anisotropy (FA)) and gray matter density (voxel-based morphometry (VBM)) were measured and compared across groups. Gray matter density was lower in left prefrontal cortex (PFC) in high pack-years smokers and was inversely related to pack-years. In contrast, left insular cortex gray matter density was higher in smokers and associated with TAS-20 total score and with difficulty-identifying-feelings factor. Further, the most highly dependent smokers showed lower prefrontal FA, which was negatively correlated with FTND. There was no correlation between pack-years and FTND in our smoker population. These data suggest chronic tobacco use is correlated with prefrontal gray matter damage , while differences in insula gray matter and PFC white matter appear to reflect stable and heritable differences between smokers and non-smokers.
authors.affiliation: Neuroimaging Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD 21224, USA.
authors.forename: Xiaochu
authors.initials: X
authors.lastname: Zhang
authors.forename: Betty Jo
authors.initials: BJ
authors.lastname: Salmeron
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Ross
authors.forename: Xiujuan
authors.initials: X
authors.lastname: Geng
authors.forename: Yihong
authors.initials: Y
authors.lastname: Yang
authors.forename: Elliot A
authors.initials: EA
authors.lastname: Stein
mesh_terms: D001925:Brain Damage, Chronic / Q000209:etiology; D002540:Cerebral Cortex / Q000473:pathology*; D004644:Emotions; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D009410:Nerve Degeneration / Q000473:pathology; D017397:Prefrontal Cortex / Q000473:pathology*; D012906:Smoke / Q000009:adverse effects; D012907:Smoking / Q000235:genetics / Q000473:pathology* / Q000523:psychology; D013850:Thinking
chemical_list: D012906:Smoke