Abstract
Neuroimaging studies have shown that heroin addiction is related to abnormalities in widespread local regions and in the functional connectivity of the brain. However, little is known about whether heroin addiction changes the topological organization of whole-brain functional networks. Seventeen heroin-dependent individuals (HDIs) and 15 age-, gender-matched normal controls (NCs) were enrolled, and the resting-state functional magnetic resonance images (RS-fMRI) were acquired from these subjects. We constructed the brain functional networks of HDIs and NCs, and compared the between-group differences in network topological properties using graph theory method. We found that the HDIs showed decreases in the normalized clustering coefficient and in small-worldness compared to the NCs. Furthermore, the HDIs exhibited significantly decreased nodal centralities primarily in regions of cognitive control network, including the bilateral middle cingulate gyrus, left middle frontal gyrus, and right precuneus, but significantly increased nodal centralities primarily in the left hippocampus. The between-group differences in nodal centralities were not corrected by multiple comparisons suggesting these should be considered as an exploratory analysis. Moreover, nodal centralities in the left hippocampus were positively correlated with the duration of heroin addiction. Overall, our results indicated that disruptions occur in the whole-brain functional networks of HDIs, findings which may be helpful in further understanding the mechanisms underlying heroin addiction.
Highlights
Drug addiction, a major social problem, appears to be a chronic brain disease that involves complex interactions between biological and environmental variables and is characterized by a compulsive drive to take drugs despite serious negative consequences [1]
Demographic information Statistical comparisons showed no significant differences in gender, age, duration of education, cigarette smoking, and head motions between the heroin group and the control group (Table 1)
We found that in heroin-dependent individuals (HDIs), the nodal centrality metrics were significantly decreased in six brain regions, the bilateral middle cingulate gyrus (MCG.L/R), left middle frontal gyrus (MFG.L), left inferior temporal gyrus (ITG.L), right precuneus (PCUN.R), and right thalamus (THA.R), most of which belong to the cognitive control network [40,41,42]; but significantly increased in three brain regions, the left hippocampus (HIP.L), left inferior occipital gyrus (IOG.L), and left lingual gyrus (LING.L)
Summary
A major social problem, appears to be a chronic brain disease that involves complex interactions between biological and environmental variables and is characterized by a compulsive drive to take drugs despite serious negative consequences [1]. Several studies that used this technique investigated heroin-related changes in spontaneous brain activity [9,10,11,12,13] and suggested that heroin addiction is related to widespread functional abnormalities in many brain regions. These regions include the amygdala [13], anterior cingulate cortex (ACC) [10], hippocampus [13], insula [13], lingual gyrus [9], orbitofrontal cortex (OFC) [9], and temporal cortex [10]. To date no study has considered heroinrelated whole-brain functional networks during the resting-state
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