Resting-state Network Evaluation Of Chronic Smokers By FMRI

Objective Smoking is one of the biggest public health problems facing the world today. The number of smokers in our country is up to 316 million. Most smokers have a strong desire to quit smoking, but only 3% to 5% of smokers can successfully quit smoking with personal perseverance. This is because tobacco can release nicotine during burning process, which has addiction. Active smokers need a cigarette at intervals to maintain the levels of nicotine in brain. So it is important to explore the effects of smoking on brain function and structure. In recent years, with multiple image technologies, scholars have found many changes to brain structures and funtion. Resting-state f MRI can detects brain functional changes. As an advanced f MRI data processing technique, independent component analysis(ICA) can isolate and analyse the changes to functional connectivity of resting-state networks. In order to explore the neuromechanism of nicotine smoking, we use ICA of resting-state functional magnetic resonance imaging(f MRI) to investigate the differences of functional connectivity of resting-state networks in chronic smokers from non-smoking controls.Methods Forty-five chronic smokers and thirty-four age and gender matched nomal nonsmoking controls were experienced resting-state f MRI scanning in 3.0T MRI scanner. During the scanning of f MRI, participants were informed to keep quiet, eyes closed, not falling asleep, keep body stationary, nor thinking a particular thing. Resting-state f MRI datas were preprocessed by DPARSFA software, including format conversing, excluding time point, time correction, head movement correction, spatial normalization and spatial smoothing. ICA of resting-state f MRI datas were proceeded by GIFT software, during which visually recognizing resting-state networks were proceeded. Differences of the function connection in each RSN between chronic smokers group and nonsmoking controls group were analyzed by SPM software which was based on Matlab platform, with the significance level of ɑ=0.05.Result 8 RSNs template which generated from chronic smokers and nomal nonsmoking controls data were recognized: anterior default network front(a DMN), posterior default network(p DMN), medial visual network(m VN), lateral visual network(l VN), occipital pole visual networks(p VN), dorsal attention network(DAN), left frontoparietal network(l FPN) and right frontoparietal network(r FPN). Differences of functional connectivity within each RSN:(1) a DMN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within a DMN include: left posterior cingulate cortex increased(t=2.35, P=0.011); left gyrus frontalis superior decreased(t =-2.95, P = 0.002), left gyrus frontalis medius decreased(t =-2.4, P = 0.009), right gyrus frontalis superior decreased(t=-2.23, P=0.014), right gyrus frontalis medius decreased(t=-2.2, P=0.015).(2) p DMN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within p DMN include: angular gyrus increased(t=-2.35, P=0.000), left gyrus frontalis superior increased(t=-3.82, P=0.000); right middle cingulate gyrus decreased(t=3.83, P=0.000).(3) m VN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within m VN include: right cuneus decreased(t=4.17, P=0.000), left calcarine decreased(t=3.08, P=0.001).(4) l VN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within l VN include: left gyrus occipital superior decreased(t=3.42, P=0.001).(5) p VN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within p VN include: right gyrus occipital medius decreased(t=4.02, P=0.000), left gyrus occipital medius decreased(t=3.58, P=0.000).(6) DAN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within DAN include: right gyrus occipital superior increased(t=3.42, P=0.001).(7) l FPN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within l FPN include: left inferior parietal lobe decrease(t=3.77, P=0.000).(8) r FPN: Compared with nomal nonsmoking controls, the functional connectivity abnormal brain regions of chronic smokers within l FPN include: right gyrus frontalis medius increased(t=3.42, P=0.001).Conclusion There are some of RSNs changes of chronic smokers compared with nomal nonsmoking controls, with multiple brain regions functional connectivity abnormalities which include functional connectivity increase and decrease.