Whole brain functional connectivity of the bilateral amygdaloid in chronic alcoholics: a restingstate functional magnetic resonance imaging study

Objective To explore the conditions of whole brain functional connectivity (FC) of the bilateral amygdaloid in resting state in chronic alcoholics. Methods Thirty-three chronic alcoholics and 36 healthy control subjects matched in gender, age, education and handedness, admitted to our hospital from October 2011 to October 2012, were enrolled as chronic alcoholics group and control group, respectively. All subjects were asked to perform both Michigan alcohol screening scale (MAST) and alcohol addiction scale (ADS) to ensure that the alcohol dependent individuals enrolled in this study reached moderate alcohol dependent. All subjects were performed MR imaging; DPARSF software was used to perform data processing which was based on MATLABE, SPM and REST operating environment. REST software was made use of the left amygdala activity peak voxel (-24, 0,-16) and right amygdala peak voxel (24, 0, 16) as seeded region of interest to get the whole brain FC mapping. Rest Slice Viewer software within REST software package was used to view statistical results. Each time series of brain regions were extracted, and correlation analysis of MAST scores with ADS scores was performed and the corresponding correlation coefficient values were recorded. Results Finally, 57 subjects (28 in chronic alcoholics group and 29 in control group) were enrolled after screening. As compared with that in the healthy controls, the FC of left pars opercularis gyri frontalis inferiorista, bilateral supramarginal gyrus, left thalamus, bilateral paracentral lobule, left precentral gyrus, right pars orbitalis gyri frontalis inferiois and right superior temporal gyrus was significantly increased in the left amygdaloid, and that of left middle occipital gyrus, left cerebellar peduncle, left orbitofrontal region, left entorhinal cortex, right cerebellum inferior semi-Lunar lobule, right cerebellar parietal and superior frontal gyrus was significantly decreased in resting state in chronic alcoholism (P<0.05); as compared with that in the control group, the FC of left pars triangularis gyri frontalis inferiorista, left middle temporal gyrus, left caudate nucleus, left precuneus, left paracentral lobule, left middle frontal gyrus and right angular gyrus was significantly increased in the right amygdaloid, and that of left cerebellar hemisphere, left orbifrontal area, right superior parietal lobule, medulla oblongata was significantly decreased in resting state in chronic alcoholism (P<0.05). In the chronic alcoholics group, the left frontal lobe was significantly negatively correlated with MAST scores (r=-0.433, P=0.021); the left precuneus (r=0.245, P=0.210), left supramarginal gyrus (r=0.187, P=0.341), right supramarginal gyrus (r=0.142, P=0.471) and right cerebellum (r=0.227, P=0.245) showed a significant positive correlation with ADS scores. Conclusion Left amygdale's function of chronic alcoholics is more easily damaged; amygdala may be involved in regulating the function of fronto-cerebellar loops, and has close relation with alcohol-related brain damage in the pathogenesis and clinical manifestations. Key words: Chronic alcoholics; Resting state functional magnetic resonance imaging; Amygdaloid; Functional connectivity