Abstract
BackgroundThe growing abuse of amphetamine-type stimulants leads to new challenges to human health. A possible addiction mechanism has been proposed by altered functional architecture of the nucleus accumbens (NAc) during resting state. NAc contains different subdivisions and they may play different roles in addiction. The aim of the present study was to examine whether there are common or distinct patterns of functional connectivity of the NAc subdivisions in amphetamine-type stimulant abusers (ATSAs).MethodsThe present study recruited 17 male ATSAs and 22 healthy male controls. All the subjects underwent resting-state functional magnetic resonance imaging (fMRI) with their eyes closed. The NAc was divided into core-like and shell-like subdivisions. We used seed-based resting-state functional connectivity (RSFC) analyses to identify differences in brain functional architecture between ATSAs and healthy controls (HCs).ResultsATSAs had lower positive RSFCs with all of the NAc subdivisions over the left orbital part of superior frontal gyrus and higher positive RSFCs with the NAc subdivisions over the left opercular part of inferior frontal gyrus than HCs, which indicates common abnormalities across the NAc subdivisions in ATSAs. In addition, the RSFCs between the NAc subdivisions and the left orbital part of superior frontal gyrus were negatively correlated with the addiction severity in ATSAs.ConclusionThese results provide evidence that there are common RSFC patterns of the NAc subdivisions in ATSAs. The abnormality indicated by disrupted functional connectivity between the NAc subdivisions and prefrontal cortex suggests abnormal interaction between the rewarding process and cognitive control in ATSAs. Our results shed insight on the neurobiological mechanisms of ATSA and suggest potential novel therapeutic targets for treatment and intervention of ATSAs.
Highlights
The growing abuse of amphetamine-type stimulants leads to new challenges to human health
We found that the positive resting-state functional connectivity (RSFC) between the nucleus accumbens (NAc) core-like subdivision and the frontal gyrus, the cingulate gyrus and the inferior parietal lobule were significantly greater compared with the NAc shell-like subdivision and the positive RSFCs between the NAc core-like subdivision and the temporal gyrus, the parahippocampus gyrus, the insula, and the supplementary motor area were significantly smaller compared with the NAc shell-like subdivision in the healthy controls (HCs) group, which is consistent with the previous study [24]
Our study showed that amphetamine-type stimulant abusers (ATSAs) had significantly reduced RSFC with the NAc subdivisions over the left orbital part of superior frontal gyrus (OFC), supporting the disrupted connectivity between the NAc and prefrontal cortices involved in the mechanism of ATSAs
Summary
The growing abuse of amphetamine-type stimulants leads to new challenges to human health. The aim of the present study was to examine whether there are common or distinct patterns of functional connectivity of the NAc subdivisions in amphetamine-type stimulant abusers (ATSAs). In China, the proportion of amphetamine-type stimulants abusers (ATSAs) is continuously increasing over the past several years [2]. Drug addiction is often related to altered functional architecture in the brain, which results in hypersensitivity to the drug and drug-related cues and further ensures the compulsive drug-seeking behavior [3]. Recent neuroimaging studies have indicated the significant functions of the reward system in drug addiction. The NAc plays a pivotal role in refining action selection and mediating the rewarding effects of drugs abuse [7]. It is generally thought that chronic exposure to addictive drugs disrupts the plasticity of the NAc, producing a pathologic motivation for addictive drug seeking
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