Topological Alterations of the Intrinsic Brain Network in Patients with Functional Dyspepsia

BACKGROUND/AIMS: Previous studies reported that integrated information in the brain ultimately determines the subjective experience of patients with chronic pain, but how the information is integrated in the brain connectome of functional dyspepsia (FD) patients remains largely unclear. The study aimed to quantify the topological changes of the brain network in FD patients. METHODS: Small-world properties, network efficiency and nodal centrality were utilized to measure the changes in topological architecture in 25 FD patients and 25 healthy controls based on functional magnetic resonance imaging. Pearson's correlation assessed the relationship of each topological property with clinical symptoms. RESULTS: FD patients showed an increase of clustering coefficients and local efficiency relative to controls from the perspective of a whole network as well as elevated nodal centrality in the right orbital part of the inferior frontal gyrus, left anterior cingulate gyrus and left hippocampus, and decreased nodal centrality in the right posterior cingulate gyrus, left cuneus, right putamen, left middle occipital gyrus and right inferior occipital gyrus. Moreover, the centrality in the anterior cingulate gyrus was significantly associated with symptom severity and duration in FD patients. Nevertheless, the inclusion of anxiety and depression scores as covariates erased the group differences in nodal centralities in the orbital part of the inferior frontal gyrus and hippocampus. CONCLUSIONS: The results suggest topological disruption of the functional brain networks in FD patients, presumably in response to disturbances of sensory information integrated with emotion, memory, pain modulation, and selective attention in patients.

Two sets of acupoint combination of similar functions engage shared neural representation: a functional magnetic resonance imaging study / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate whether the neural representations underlying alternating two acupoint combinations (ACs) are the same or not.</p><p><b>METHODS</b>In this functional magnetic resonance imaging study, two sets of analgesia ACs were utilized, including Waiguan (TE5) and Qiuxu (GB40) for Group A, and Neiguan (PC6) and Taichong (LR3) for Group B, which are the most commonly adopted in clinical treatment. Each group had 20 healthy subjects. An experimental design was proposed, which consisted of a pre-needling resting phase, a needling phase and a post-needling resting phase. This paradigm optimally mimics the clinical protocol as well as focuses on both the stimulation and the resting periods. The results were subjected to general linear model analysis, conjunction analysis and the functional connectivity analysis.</p><p><b>RESULTS</b>The rostral anterior cingulated cortex was engaged in the initiative period of the acupuncture effect in both groups, and it was chosen as the seed region for the functional connectivity analysis for the following resting period. The results showed that several shared brain regions were involved in both groups, in particular the insula, amygdala and hypothalamus. Moreover, significant differences were located at the posterior cingulated cortex as revealed by a two sample -test (P<0.05, corrected). Other regions showed no significant differences. This finding was further supported by the spatial correlation analysis that the two groups were significantly correlated (r =0.51, P<0.01).</p><p><b>CONCLUSION</b>This preliminary research helps us understand the neurophysiological mechanisms of acupuncture when following clinical guidelines on ACs, as well as provides an important opportunity to develop better treatment strategies for reducing, or even preventing pain.</p>

Abnormal function of the posterior cingulate cortex in heroin addicted users during resting-state and drug-cue stimulation task / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Previous animal and neuroimaging studies have demonstrated that brain function in heroin addicted users is impaired. However, the posterior cingulate cortex (PCC) has not received much attention. The purpose of this study was to investigate whether chronic heroin use is associated with craving-related changes in the functional connectivity of the PCC of heroin addicted users.</p><p><b>METHODS</b>Fourteen male adult chronic heroin users and fifteen age and gender-matched healthy subjects participated in the present study. The participants underwent a resting-state functional magnetic resonance imaging (fMRI) scan and a cue-induced craving task fMRI scan. The activated PCC was identified in the cue-induced craving task by means of a group contrast test. Functional connectivity was analyzed based on resting-state fMRI data in order to determine the correlation between brain regions. The relationship between the connectivity of specific regions and heroin dependence was investigated.</p><p><b>RESULTS</b>The activation of PCC, bilateral anterior cingulate cortex, caudate, putamen, precuneus, and thalamus was significant in the heroin group compared to the healthy group in the cue-induced craving task. The detectable functional connectivity of the heroin users was stronger between the PCC and bilateral insula, bilateral dorsal striatum, right inferior parietal lobule (IPL) and right supramarginal gyrus (P < 0.001) compared to that of the healthy subjects in the resting-state data analysis. The strength of the functional connectivity, both for the PCC-insula (r = 0.60, P < 0.05) and for PCC-striatum (r = 0.58, P < 0.05), was positively correlated with the duration of heroin use.</p><p><b>CONCLUSION</b>The altered functional connectivity patterns in the PCC-insula and PCC-striatum areas may be regarded as biomarkers of brain damage severity in chronic heroin users.</p>