Xiaoqi Lu

The implication of frontostriatal circuits in young smokers: A resting-state study

The critical roles of frontostriatal circuits had been revealed in addiction. With regard to young smokers, the implication of frontostriatal circuits resting‐state functional connectivity (RSFC) in smoking behaviors and cognitive control deficits remains unclear. In this study, the volume of striatum subsets, i.e., caudate, putamen, and nucleus accumbens, and corresponding RSFC differences were investigated between young smokers (n1 = 60) and nonsmokers (n2 = 60), which were then correlated with cigarette smoking measures, such as pack_years‐cumulative effect of smoking, Fagerström Test for Nicotine Dependence (FTND)‐severity of nicotine addiction, Questionnaire on Smoking Urges (QSU)‐craving state, and Stroop task performances. Additionally, mediation analysis was carried out to test whether the frontostriatal RSFC mediates the relationship between striatum morphometry and cognitive control behaviors in young smokers when applicable. We revealed increased volume of right caudate and reduced RSFC between caudate and dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex in young smokers. Significant positive correlation between right caudate volume and QSU as well as negative correlation between anterior cingulate cortex‐right caudate RSFC and FTND were detected in young smokers. More importantly, DLPFC‐caudate RSFC strength mediated the relationship between caudate volume and incongruent errors during Stroop task in young smokers. Our results demonstrated that young smokers showed abnormal interactions within frontostriatal circuits, which were associated with smoking behaviors and cognitive control impairments. It is hoped that our study focusing on frontostriatal circuits could provide new insights into the neural correlates and potential novel therapeutic targets for treatment of young smokers. Hum Brain Mapp 37:2013–2026, 2016.

White matter integrity in young smokers: a tract-based spatial statistics study.

Previous diffusion tensor imaging (DTI) studies revealed contradictory effects of smoking on fractional anisotropy (FA). Multiple DTI‐derived indices may help to deduce the pathophysiological type of white matter (WM) changes and provide more specific biomarkers of WM neuropathology in the whole brain of young smokers. Twenty‐three young smokers and 22 age‐, education‐ and gender‐matched healthy non‐smoking controls participated in this study. Tract‐based spatial statistics was employed to investigate the WM microstructure in young smokers by integrating multiple indices, including FA, mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD). Compared with healthy non‐smoking controls, young smokers showed significantly increased FA with increased AD and decreased RD in several brain regions, while no difference in MD was observed. Specifically, the overlapped WM regions with increased FA, increased AD and decreased RD were found in the right posterior limb of the internal capsule, the right external capsule and the right superior corona radiata. Additionally, average FA and RD values in the WM regions mentioned earlier were significantly correlated with pack‐years and Fagerström Test for Nicotine Dependence, while no correlation in AD was found. The WM tracts with increased FA may be more associated with RD, rather than AD in young smokers. We suggested that WM properties of several fibres in young smokers may be the biomarker as the cumulative effect and severity of nicotine dependence.

Intra-regional and inter-regional abnormalities and cognitive control deficits in young adult smokers

Tobacco use during later adolescence and young adulthood may cause serious neurophysiological changes; rationally, it is extremely important to study the relationship between brain dysfunction and behavioral performances in young adult smokers. Previous resting state studies investigated the neural mechanisms in smokers. Unfortunately, few studies focused on spontaneous activity differences between young adult smokers and nonsmokers from both intra-regional and inter-regional levels, less is known about the association between resting state abnormalities and behavioral deficits. Therefore, we used fractional amplitude of low frequency fluctuation (fALFF) and resting state functional connectivity (RSFC) to investigate the resting state spontaneous activity differences between young adult smokers and nonsmokers. A correlation analysis was carried out to assess the relationship between neuroimaging findings and clinical information (pack-years, cigarette dependence, age of onset and craving score) as well as cognitive control deficits measured by the Stroop task. Consistent with previous addiction findings, our results revealed the resting state abnormalities within frontostriatal circuits, i.e., enhanced spontaneous activity of the caudate and reduced functional strength between the caudate and anterior cingulate cortex (ACC) in young adult smokers. Moreover, the fALFF values of the caudate were correlated with craving and RSFC strength between the caudate and ACC was associated with the cognitive control impairments in young adult smokers. Our findings could lead to a better understanding of intrinsic functional architecture of baseline brain activity in young smokers by providing regional and brain circuit spontaneous neuronal activity properties as well as their association with cognitive control impairments.

The implication of salience network abnormalities in young male adult smokers

Studying the neural correlates of smoking behaviors in young adulthood is of great importance to improve treatment outcomes. In previous addiction studies, the important roles of the salience network (SN) in drug cue processing and cognitive control have been revealed. Unfortunately, few studies focused on the resting-state functional connectivity and structural integrity abnormalities of SN in young adult smokers, and less is known about its association with smoking behaviors and cognitive control deficits. Thirty-one young male adult smokers and 30 age-, education- and gender-matched nonsmokers participated in this study. The structural and functional connectivity differences of SN were investigated between young adult smokers and nonsmokers by using diffusion tensor imaging (DTI) and resting-state functional connectivity (RSFC), which were then correlated with the smoking behavioral assessments (pack-years and Fagerström Test for Nicotine Dependence (FTND)) as well as impaired cognitive control measured by the Stroop task. Within SN, reduced RSFC and increased fractional anisotropy (FA) were found between the anterior cingulate cortex (ACC) and the right insula in young adult smokers relative to nonsmokers. The RSFC between the ACC and right insula was negatively correlated with the number of errors during the incongruent condition of the Stroop task in young adult smokers. Additionally, the right insula-ACC RSFC was negatively correlated with pack-years in young adult smokers. Our results revealed abnormal RSFC and structural integrity within the SN in young adult smokers, which shed new insights into the neural mechanism of nicotine dependence.

Neural correlates of 12-h abstinence-induced craving in young adult smokers: a resting-state study

Studying the neural correlates of craving to smoke in young adulthood is of great importance to improve treatment outcomes in nicotine dependence. Previous nicotine dependence studies mainly focused on the neural substrates of craving elicited by smoking-related cues. More explicit attention to abstinence-induced craving during resting state in nicotine dependence has the potential to yield valuable information about craving, and characterizing this kind of craving is critical for developing effective interventions. Twenty-five young male smokers were enrolled in the present study. A within-subject experiment design was carried out to compare regional homogeneity (ReHo) between 12-h smoking abstinence and smoking satiety conditions during resting state in young adult smokers. Then, the ReHo changes associated with smoking abstinence (compared with satiety) were further examined for correlations with abstinence-induced changes in subjective craving. We found young adult smokers in abstinence state (compared with satiety) had higher ReHo in brain regions in fronto-striatal circuits including bilateral caudate, anterior cingulate cortex (ACC) and bilateral dorsal lateral prefrontal cortex (DLPFC), as well as brain regions in default mode network (DMN) including posterior cingulate cortex (PCC)/precuneus and angular gyrus. Additionally, we found the ReHo changes of the ACC and the bilateral caudate were positively correlated with the changes in craving induced by abstinence (i.e., abstinence minus satiety) in young adult smokers. The present findings improve the understanding of the effects of acute smoking abstinence on spontaneous brain activity and may contribute new insights into the neural mechanism of abstinence-induced craving in nicotine dependence.

The left dorsolateral prefrontal cortex and caudate pathway: New evidence for cue-induced craving of smokers: DLPFC and Caudate Pathway

Although the activation of the prefrontal cortex (PFC) and the striatum had been found in smoking cue induced craving task, whether and how the functional interactions and white matter integrity between these brain regions contribute to craving processing during smoking cue exposure remains unknown. Twenty‐five young male smokers and 26 age‐ and gender‐matched nonsmokers participated in the smoking cue‐reactivity task. Craving related brain activation was extracted and psychophysiological interactions (PPI) analysis was used to specify the PFC‐efferent pathways contributed to smoking cue‐induced craving. Diffusion tensor imaging (DTI) and probabilistic tractography was used to explore whether the fiber connectivity strength facilitated functional coupling of the circuit with the smoking cue‐induced craving. The PPI analysis revealed the negative functional coupling of the left dorsolateral prefrontal cortex (DLPFC) and the caudate during smoking cue induced craving task, which positively correlated with the craving score. Neither significant activation nor functional connectivity in smoking cue exposure task was detected in nonsmokers. DTI analyses revealed that fiber tract integrity negatively correlated with functional coupling in the DLPFC‐caudate pathway and activation of the caudate induced by smoking cue in smokers. Moreover, the relationship between the fiber connectivity integrity of the left DLPFC‐caudate and smoking cue induced caudate activation can be fully mediated by functional coupling strength of this circuit in smokers. The present study highlighted the left DLPFC‐caudate pathway in smoking cue‐induced craving in smokers, which may reflect top‐down prefrontal modulation of striatal reward processing in smoking cue induced craving processing. Hum Brain Mapp 38:4644–4656, 2017.

Reduced Thalamus Volume May Reflect Nicotine Severity in Young Male Smokers

Introduction Nicotine acts as an agonist at presynaptic nicotinic acetylcholine receptors and to facilitate synaptic release of several neurotransmitters including dopamine and glutamate. The thalamus has the highest density of nicotinic acetylcholine receptors in the brain, which may make this area more vulnerable to the addictive effects of nicotine. However, the volume of thalamus abnormalities and the association with smoking behaviors in young smokers remains unknown. Methods Thirty-six young male smokers and 36 age-, gender- and education-matched nonsmokers participated in the current study. The nicotine dependence severity and cumulative effect were assessed with the Fagerström test for nicotine dependence (FTND) and pack-years. We used subcortical volume analyses method in FreeSurfer to investigate the thalamus volume differences between young smokers and nonsmokers. Correlation analysis was used to investigate the relationship between thalamus volume and smoking behaviors (pack-years and FTND) in young smokers. Results and Conclusions Relative to nonsmokers, the young smokers showed reduced volume of bilateral thalamus. In addition, the left thalamus volume was correlated with FTND in young smokers. It is hoped that our findings can shed new insights into the neurobiology of young smokers. Implications In this article, we investigated the changes of thalamus volume in young male smokers compared with nonsmokers. Reduced left thalamus volume was correlated with FTND in young smokers, which may reflect nicotine severity in young male smokers.

Research and Implementation of Converting DICOM Multi-Frame Medical Image to Multimedia Format

Objective Converting DICOM Multi-frame image to multimedia format is implemented. Methods By parsing DICOM structure, using DCMTK as supportive toolkit and based on object-oriented programming, pixel data in DICOM multi-frame image are written into multimedia file. Results A lot of images are tested from different modalities such as MR, NM, XA, etc. And all of them can be converted to multimedia format very well. Conclusion Converted multimedia files can fully meet the demand, which facilitate physicians for better observing the dynamic process of the examining position of patients.

Altered interhemispheric resting-state functional connectivity in young male smokers

With the help of advanced neuroimaging approaches, previous studies revealed structural and functional brain changes in smokers compared with healthy non‐smokers. Homotopic resting‐state functional connectivity between the corresponding regions in cerebral hemispheres may help us to deduce the changes of functional coordination in the whole brain of young male smokers. Functional homotopy reflects an essential aspect of brain function and communication between the left and right cerebral hemispheres, which is important for the integrity of brain function. However, few studies used voxel mirrored homotopic connectivity (VMHC) method to investigate the changes of homotopic connectivity in young male smokers. Twenty‐seven young male smokers and 27 matched healthy male non‐smokers were recruited in our study. Compared with healthy male non‐smokers, young male smokers showed decreased VMHC values in the insula and putamen, and increased VMHC values in the prefrontal cortex. Correlation analysis demonstrated that there were significant positive correlations between the average VMHC values of the prefrontal cortex and pack‐years in young male smokers. In addition, significant negative correlation was found between the average VMHC values in the insula and pack‐years. Our results revealed the disrupted homotopic resting‐state functional connectivity in young male smokers. The novel findings may extend our understanding of smoking.

Decreased Global Network Efficiency in Young Male Smoker: An EEG Study during the Resting State

Previous electroencephalogram (EEG) studies revealed reduced spectral power during the resting state in smokers. However, few studies investigated the changes of global brain networks during the resting state in young smokers by EEG. In the present study, we used minimum spanning tree (MST) to assess the differences of global network efficiency between young smoker (n = 20) and nonsmokers (n = 20). Compared with healthy nonsmokers, young smokers showed decreased leaf fraction, kappa value, increased diameter and eccentricity value in alpha band (r = 0.574, p = 0.008), which suggested the global network efficiency was decreased in young smokers. We also found positive correlation between leaf fraction and onset time of smoking in smokers. These results provided more scientific evidence of the abnormal neural oscillations of young smokers and improved our understanding of smoking addiction.