Abnormal Functional Connectivity Of The Anterior Cingulate Cortex In Classical Trigeminal Neuralgia:A Resting-State FMRI Study

Objective: Classical trigeminal neuralgia(CTN)is a severe neuropathic pain in the maxillofacial region caused by neurovascular compression.Long-term pain stimulation can lead to brain function altered.The anterior cingulate gyrus(ACC)is an important hinge of the pain pathway.It is not clear whether the functional connectivity(FC)between ACC and other brain regions in CTN patients are altered by chronic pain stimulation.Therefore,this study intends to use FC analysis technique of resting-state functional magnetic resonance imaging(Rs-fMRI)to investigate the abnormal FC patterns of ACC in CTN patients.Methods: 25 CTN patients and 25 healthy controls matched with age,gender and handedness were recruited,the general clinical data of the two groups were obtained and the pain degree of CTN patients was evaluated by VAS score.All subjects underwent Rs-fMRI scan.Using DPARSF2.3 and SPM8 software on the MATLAB platform,the two groups of resting state data were processed and statistically analyzed,including data preprocessing,selecting left and right ACC as two seed regions to calculate the FC with the whole brain,the group comparison obtains the different seed FC brain region.Using SPSS19.0 software,according to the normality test results,select Pearson correlation or Spearman correlation analysis method to analyze the correlation between FC value with duration and VAS score in abnormal brain regions of CTN group respectively.Results:(1)CTN group included 11 male,14 female,age range 26~76 years,mean age 55.72±12.82 years,duration range 0.04~20 years,mean duration 3.92±4.30 years,neurovascular compression: 7 left,18 right,VAS score range 5~9,mean score 6.28±1.43;HC group included 11 male,14 female,age range 25~71 years,mean age 55.56±11.81 years;(2)Compared with HC,CTN patients showed increased FC between the left ACC and left cerebellum Crus I /Crus II/VI,right lingual gyrus/ inferior occipital gyrus/calcarine,decreased FC with the left insula/putamen,bilateral mid cingulate(Gaussian random field,GRF corrected,p<0.05);(3)increased FC between the right ACC and right fusiform gyrus/ lingual gyrus /inferior occipital gyrus(GRF corrected,p<0.05);(4)None of the disrupted FC in CTN patients was significantly correlated with the duration and VAS score(p>0.05).Conclusions:(1)The FC patterns of ACC were altered in CTN patients,responsible for pain perception,movement,cognition and emotion processing,suggesting that they might be related to their underlying pathophysiological mechanisms;(2)Using Rs-fMRI techniques combined with FC analysis could provide valuable imaging evidence for better understanding the pathophysiological mechanism of CTN.