Functional Neuroimaging Study On Baseline Brain Activity In Patients With Functional Constipation

With current economic development,living standards are improving constantly,and daily eating habits are also changing.At the same time,today’s society faces,many pressures,such as mental stress,as well as long-term sub-health state,with the incidence of functional gastrointestinal disease increasing.Functional constipation(FC)is a common functional gastrointestinal disease with a high incidence in clinics.This study found that FC can cause a variety of diseases,such as colorectal cancer,chronic encephalopathy,breast disease,Alzheimer’s disease,etc.These problems have seriously affected the quality of people’s lives in today’s society.In the early stage of neuroimaging studies of functional gastrointestinal diseases,this study found that the emotional processing network was involved in emotion processing,as well as the brain regions responsible for the control of somatosensory and motor processes which had abnormal changes.However,the mechanism of the central nervous system of brain gut interaction,such as constipation,has rarely been studied.The imaging study of functional gastrointestinal diseases with irritable bowel syndrome(IBS)as the main focus provided us with an inspiration to study the central mechanism of functional constipation with magnetic resonance imaging.Is functional constipation similar to IBS with regards to central nervous system(CNS)pathways? One clinical study found that long-term functional constipation patients were accompanied by anxiety,depression,and mental disorders,with mental disorders increasing the symptoms of constipation,resulting in a vicious cycle.It remains unclear if Functional constipation with psychiatric-disorder(FCPD)is caused by the twoway gut-brain axis and if abnormalities of brain regions are involved with emotionalprocessing and stress-response contributing to FCPD.In addition,epidemiological studies have shown that women are 2 times more likely to suffer from constipation,the functional level of cerebral function in patients with functional constipation in different gender groups has not been studied.In view of the above questions,this paper studied the central nervous system of functional constipation via resting state functional magnetic resonance imaging(f MRI)and Granger causality connection analysis method.The main contents are as follows: firstly,the imaging study of functional constipation was carried out.The results showed that compared with the healthy controls(HC),there were significant differences in the baseline brain activity in patients with FC,including responsibility for emotion regulation(dorsal anterior cingulate cortex(d ACC),anterior insula(a INS),orbitofrontal cortex(OFC),hippocampus),and responsibility for somatosensory and control movements(somatosensory motor area(SMA),precentral gyrus(Pre Cen)).Based on the above differences,the Granger causality connectivity analysis found that: the connection between the OFC and d ACC to the a INS and HIPP was increased,and the connection from the SMA and Pre Cen to the a INS and HIPP was weakened.Secondly,the study of functional constipation with mental disorders was carried out.Imaging results revealed that compared with the HC,both FCPD and FC showed significant basal brain functional abnormalities in regions implicated in emotionalprocess-modulation and motor-control.Furthermore,FCPD also showed differences in the ventromedial prefrontal cortex(VMPFC),amygdala and hypothalamus which are involved with emotional-arousal and hypothalamic-pituitary-adrenal-axis.Granger causality connectivity analysis revealed that in the FCPD group,brain regions(OFC/insula/amygdala/hippocampus)had greater connectivity to both the hypothalamus and SMA.Finally,the imaging study of functional constipation was carried out for the gender difference.The study found that there were significant differences responsible for emotion regulation(OFC,VMPFC)and somatosensory/control movements(SMA,Pre Cen)between female patients and male patients.Granger causality analysis found an effective connection enhancement from the VMPFC to the INS,SMA,and Pre Cen.Based on the study of the physiological mechanism of functional constipation via f MRI,we found that patients with functional constipation compared to the normal subjects in the internal feelings,physical sensory and motor control and other brain areas there was a significant difference.Patients with functional comorbidities with mental disorders also found abnormalities that belong to the emotional wake-up network and the HPA axis.The above studies not only provide imaging evidence for the central nervous system of functional constipation,but also provide theoretical support for future research in related fields.