Analysis Of Brain Functional Activities In Autism Spectrum Disorders Based On Resting FMRI

Autism spectrum disorder(ASD)is a neurodevelopmental disorder with social disorder,narrow interest and stereotyped behavior as the core defects.The number of people diagnosed with ASD has increased significantly in recent 10 years,but the pathological mechanism of the disease is still unclear,and there is a lack of clear treatment ideas.Therefore,exploring the pathological mechanism of ASD is an important task in related fields.In recent years,resting fMRI has been widely used to observe the brain lesions of ASD patients and explore the underlying neural mechanism because it has no specific task and is easy to implement in the patient population.However,at present,there are few studies focusing on local brain abnormalities in ASD patients,and the observation angle is single;There are many studies focusing on the brain functional network of ASD,and it is a research hotspot to use graph theory to analyze and observe the abnormal topological properties of brain network of ASD patients.However,these ASD-related graph theory studies use brain maps or templates made based on healthy people to construct brain networks,and lack the exploration of topological properties of abnormal brain networks with ASD-specific characteristics.In view of this,using the brain image data in the autism imaging exchange program,the researchers included 158 ASD patients and 207 healthy controls,and designed two studies to observe the brain functional activities of ASD patients.In Study 1,by calculating the subjects’ amplitude of low frequency fluidization(ALFF),fractional amplitude of low frequency fluidization(fALFF),percent amplitude of fluidization(PerAF),regional consistency(Re Ho)and degree centrality(DC),from voxel level The local brain abnormalities of ASD patients were studied from multiple perspectives such as local level and whole brain level.In Study 2,based on the local abnormal brain area in Study 1,the functional connectivity(FC)calculation based on the region of interest was carried out.Further,the clustering coefficient and the shortest path length of the brain network composed of FC matrix were calculated by graph theory analysis,and the brain network abnormalities of ASD were observed from the two aspects of FC and global topological attributes.The results showed that in terms of local brain abnormalities,the abnormalities were mostly found in bilateral superior frontal gyrus from the perspective of voxel levels(ALFF,fALFF and PerAF),and the index values of ASD patients were higher than those of healthy controls,and the decrease of PerAF was only found in the left precuneus;From the local level(Re Ho),the synchronization of neural activity in the right superior temporal gyrus and right medial superior frontal gyrus increased in ASD patients compared with healthy controls,and decreased in the left precuneus region.From the whole brain level(DC),the connection between the right middle orbitofrontal gyrus,the right thalamus and the left caudate nucleus and the whole brain in ASD patients was stronger than that in healthy controls.In terms of brain network abnormalities,the FC of left caudate nucleus and left precuneus in ASD patients decreased significantly,the FC of left caudate nucleus,left superior frontal gyrus and right medial superior frontal gyrus increased significantly,and the FC of right thalamus and left precuneus also increased significantly;In terms of global topological attributes,no significant differences were found in clustering coefficient and shortest path length between the two groups.This shows that there are local brain dysfunction in multiple brain regions of ASD patients,most of which show the characteristics of local brain hyperactivity,and only the left precuneus shows a decrease in local brain activity;On the brain function network composed of local abnormal brain regions,the abnormalities were concentrated in the left caudate nucleus,the left precuneus and FC in other brain regions,and the changes of FC increased and decreased.These brain functional abnormalities are related to the occurrence and severity of the main clinical symptoms of ASD,which promotes the understanding of the neural mechanism of ASD abnormalities and provides a reference for the diagnosis and treatment of ASD.