Changes of Functional and Effective Connectivity in Smoking Replenishment on Deprived Heavy Smokers: A Resting-State fMRI Study

Abstract

Previous researches have explored the changes of functional connectivity caused by smoking with the aid of fMRI. This study considers not only functional connectivity but also effective connectivity regarding both brain networks and brain regions by using a novel analysis framework that combines independent component analysis (ICA) and Granger causality analysis (GCA). We conducted a resting-state fMRI experiment in which twenty-one heavy smokers were scanned in two sessions of different conditions: smoking abstinence followed by smoking satiety. In our framework, group ICA was firstly adopted to obtain the spatial patterns of the default-mode network (DMN), executive-control network (ECN), and salience network (SN). Their associated time courses were analyzed using GCA, showing that the effective connectivity from SN to DMN was reduced and that from ECN/DMN to SN was enhanced after smoking replenishment. A paired t-test on ICA spatial patterns revealed functional connectivity variation in regions such as the insula, parahippocampus, precuneus, anterior cingulate cortex, supplementary motor area, and ventromedial/dorsolateral prefrontal cortex. These regions were later selected as the regions of interest (ROIs), and their effective connectivity was investigated subsequently using GCA. In smoking abstinence, the insula showed the increased effective connectivity with the other ROIs; while in smoking satiety, the parahippocampus had the enhanced inter-area effective connectivity. These results demonstrate our hypothesis that for deprived heavy smokers, smoking replenishment takes effect on both functional and effective connectivity. Moreover, our analysis framework could be applied in a range of neuroscience studies.

Cocaine addiction related reproducible brain regions of abnormal default-mode network functional connectivity: A group ICA study with different model orders

“…The model orders tested in our experiment were between 10 and 50, since the common model order settings in functional connectivity analyses of large-scale brain networks are within this range (e.g., [9,12,15,18]). In our experiment, from model order 60, the DMN was decomposed into more than two parts (i.…”

“…In drug addiction studies, resting-state fMRI experiment, in which participants are scanned without performing any tasks, has been widely adopted to explore abnormal brain mechanisms [9,13,19,21,24]. Resting-state functional connectivity, defined as the temporal correlation of blood-oxygenation-level-dependent (BOLD) signals in different regions of the "resting" brain, is a kind of measurement of the brain's functional organization [10].…”

“…It is associated with memory, attention and decision-making [3,7]. Since the brain circuits of memory and selfmonitoring are believed to be impaired in drug addicts, the DMN has attracted specific attention in drug addiction studies [9,18,21].…”

Reduced specialized processing in psychotic disorder: a graph theoretical analysis of cerebral functional connectivity

“…2010; Ma et al. 2011; Ding and Lee 2013). The patient population included 26 patients with a diagnosis other than schizophrenia.…”

Cigarette smoking leads to persistent and dose-dependent alterations of brain activity and connectivity in anterior insula and anterior cingulate

“…In the field of neuroimaging, several functional magnetic resonance imaging (fMRI) studies focused on differences in brain activity between control and active smokers who were abstinent for relatively short periods of time (up to 24 hours) to investigate the neurobiological mechanisms underlying nicotine abstinence and smoking addiction (Carroll et al 2013;Ding & Lee 2013;Sweitzer et al 2013;Geier et al 2014). These findings have indicated a network of brain regions that underlie craving in addiction in general (Luigjes et al 2012), with cravingrelated information being processed in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC) and nucleus accumbens.…”