Degree Centrality And Functional Connection Assessment Of Resting State FMRI Study In Nicotine Addicts

Background and purposeSmoking is one of the leading causes of death in the world.About half of long-term smokers die from smoking-related diseases.There is growing evidence that chronic smoking is a respiratory disease for most lung cancers,chronic obstructive pulmonary disease,emphysema,etc.There are direct causes of cardiovascular disease and many other deadly diseases such as the central nervous system.Smoking addiction is a complex and difficult to treat brain-based disease.Nicotine is a component of tobacco and a major cause of tobacco addiction.Chronic exposure to nicotine can trigger nerve adaptation and promote continued use of tobacco.Craving is an important symptom of nicotine dependence,usually caused by smoking cessation and relieved by smoking.During smoking cessation,nicotine abstinence produces a series of withdrawal symptoms,including impaired speech and working memory.Nicotine dependence is characterized by dysfunction of the neural circuit,especially in the reward system,also known as the mesoderm.Nicotine causes up-regulation of acetylcholine receptors,which regulates the enhancement of nicotine through nicotine interaction with the dopamine system at the midbrain cortical margin,leading to dependence,which may lead to nicotine-dependent dependence to compulsively seek and smoke cigarettes,which has a detrimental effect on health.Thenew degree centrality method is a graph-based network organization measurement that measures the functional relationship between a brain region and other brain regions in the whole connection matrix of the brain at the voxel level,reflecting the entire connection matrix of the brain.It reflects the number of transient functional connections between a region of the brain entire connection matrix and the rest of the brain.This study focuses on the network structure,and evaluates the centrality of brain network connectivity of nicotine dependent patients with resting brain function based on the degree centrality method,revealing the intrinsic connection model aimed at exploring the whole brain function network of nicotine dependent patients.Materials and methodsThis study used German Siemens 3.0T Magnetom Skyra magnetic resonance imaging equipment to acquire images.Magnetic resonance imaging were performed on 89 nicotine dependent patients and 62 normal volunteers.Before the experimental study,we detailed the subjects’ attention to the examination,the purpose of the study,the experimental procedure and the discomfort that may occur during the examination.Routine MRI scans and f-MRI sequence scans were performed on all subjects.The DPARSF software was used to preprocess the resting state f MRI data,and the age and education level were used as covariates,including data format conversion,slice timing,realignment,spatial normalization and spatial smoothing steps.To calculate voxel-oriented degree centrality values,voxel-based whole brain correlation analysis was performed on preconditioned resting state MRI data using DPARSF software.A two-sample t-test was performed on the nicotine-dependent group and the control group using the SPM8 software based on the Matlab platform.We then used DPARSF software for further functional connectivity analysis,using areas that showed significant changes in the degree centrality analysis,providing detailed information about the connectivity between voxels and specific regions being altered.A two-sample t-test was performed on the nicotine-dependent group and the control group using SPM8 software,and the test level α was 0.05.ResultsThe increase of DC value in the nicotine-dependent group was mainly in the limbic lobe(t=4.78,P=0.000),posterior cingulate gyrus(t=4.86,P=0.000)and cuneus(t=4.75,P=0.000)(P<0.05,FWE corrected).The DC value in the pons(t=-3.19,P=0.001),insula(t=-3.20,P=0.001)and right temporal lobe(t=-3.18,P=0.001)was decreased(P<0.05,FWE corrected).Taking the meaningful brain region of the abnormal DC value as the seed point,the result showed that the FC value of the occipital lobe cuneus(t =-3.85,P =0.001),cuneus(t=-3.82,P=0.001)and cingulate gyrus(t=-4.24,P=0.001)was decreased in the smoking group(P<0.05,uncorrected).ConclusionsBased on the voxel correlation analysis,this study found that the nicotine dependent patients have abnormal connectivity of the whole brain,especially the default mode network,visual cortex,limbic lobe and insula.The changes in functional connectivity are related to the patient’s brain function and brain network,suggesting that these indicators may be biomarkers of disease.Current research can provide more information about the mechanisms of brain function changes in nicotine depends.