Alterations Of Brain Functional Network In Patients With Memory Disorder After Concussion:a Resting State F-MRI Investigation

Objective To investigate the alterations of brain functional network and discuss mechanism of memory disorder after concussion based on resting-state f MRI.(1)To study the alteration of betweenness and local network efficiency in patients with mild brain injury based on graph theory.(2)To study the alteration of the parahippocampal gyrus functional(PG)connectivity in post-concussion syndrome(PCS)patients by resting-state functional magnetic resonance imaging.(3)To investigate the significance of altered functional connectivity between PCC,precuneus and whole brain in the patients with memory disorder after concussion by resting-state functional magnetic resonance imaging(f MRI).Methods(1)18 patients with the deficit of memory in the period of 3months after mild brain injury are enrolled.18 healthy people paired in sexy,age and education also enrolled as control,two groups data of resting state f MRI was collected,the data dealed with software of gretna to obtain the Martix of network,Betweenness and local efficiency of network.Two independdent group test are used to deal with the value of Betweenness for statistical significant different brain regions.Two independdent group test are also used to deal with the results of local efficiency of network in different thresholds and the changs of local efficiency network are compared in the threshold value rang of 0.1 ? Sparsity ? 0.4.(2)The resting-state f-MRI data acquired from 30 PCS patients and 30 health volunteers.The right and left PG were selected as region of interest to make functional connectivity(FC)calculation with the whole brain after the data preprocessing,and then the results were did statistical analysis with the health controls.At last the brain regions with altered functional connectivity with the PG were cleared after the study.(3)The resting-state f-MRI data acquired from 30 PCS patients and 30 health volunteers.The right and left PCC were selected as region of interest to make functional connectivity(FC)calculation with the whole brain after the data preprocessing,and then the results were did statistical analysis with the health controls.At last the brain regions with altered functional connectivity with the PCC were cleared after the study.Results(1)The PCS data compared with healthy control the brain region with decreased betweenness was left superior frontal gyrus,left lingualis gyrus,left hippocampus and left upper occipital lobe.The enhanced brain region was right hippocampus.The PCS patients' local brain efficiency was reduced compared with healthy controls.(2)Compared with the health controls,left PG in PCS patients showed decreased FC with bilateral prefrontal lobe,bilateral temporal lobe and right precuneus et al,on the contrary with the increased FC with occipital lobe,bilateral lingual gyrus and left superior parietal lobule.The right PG in PCS patients showed decreased FC with left inferior frontal gyrus,right temporal lobe,and occipital lobe.Similarly,it had the increased FC with bilateral prefrontal lobe and angular gyrus,left inferior temporal gyrus,central occipital lobe and superior parietal lobule,right lingual gyrus et al.(3)The data analysis revealed PCC had a significant enhanced FC with medial prefrontal cortex,posterior cingulate cortex,superior parietal lobule and precuneus both in PCS patients and health volunteers.However,compared with the health controls,left PCC in PCS patients showed enhanced FC with bilateral precunues,bilateral middle cingulate and right PCC,on the contrary with the decreased FC with bilateral supramarginal gyrus,bilateral superior temporal gyrus and bilateralsupplementary motor area et al.The right PCC in PCS patients showed decreased FC with bilateral supramarginal gyrus,bilateral superior temporal gyrus and bilateralsupplementary motor area et al.Similarly,it had the enhanced FC with bilateral precunues and left frontal lobe.Conclusions(1)The study found the changes in betweenness of brain network and local network efficiency,the alteration in betweenness may lead to the decline of local brain network efficiency..(2)There were PG functional connectivity abnormity in PCS patients that may lead to memory disorder.(3)There were decreased FC between PCC and prefrontal lobe,temporal lobe,parital lobe which may lead to memory disorder after concussion.And it is interesting that the FC between PCC and precuneus were observably enhanced that may be the compensatory effect to memory disorder.