Amplitude Of Low-frequency Fluctuation Study Of Rs-fMRI In The Comparation Of The Young People And The Elderly

Objective:With the approach of the aging society, brain aging attractsgreater attention in the field of medicine. Many subjects carried out wide anddeep studies on brain aging. With the age growing, the cells, the morphology,and the function of the brain tissue were declining. Thus the functions of thebody were affected, such as coordination, orientation ability, memory,cognitive ability and thinking, etc.The main changes in the morphology appearances thinned cortex,narrowed gyrus, thickened meningeal, widened sulci, enlarged ventricle, etc.However, in recent years,numbers of srudies have shown that the functions ofthe elderly not only affected by structure changes, but also affected by brainfunction. In this study, we studied the differences of the brain activity betweenthe young and the elderly group in the resting state, using amplitude oflow-frequency fluctuation(ALFF) study of resting-state functionalMRI(rs-fMRI).Methods: The subjects were divided into two groups: the young groupincluding60participantes (23males,37females, range from22to31years,mean age:26.2±1.9years); the elderly group including61participantes (23males,38females, range from45to65years, mean age:52.6±5.9years). Thevolunteers had no associated trauma and symptoms of brain injury, had noHypertension, diabetes and other diseases could cause vascular injury. Theyalso had no smoking, drinking and other bad habits.They all underwent routinescanning, most of them appeared normal or a small number of smalldegeneration stove appeared. Then the resting-state functional magneticresonance image data was acquisitioned. Next, we taked three softwares(DPARSF, REST and xjviex),used to preprocess all the date we acquisitioned,ALFF and fALFF computation and statistical analysis (two samples T test). And then we observed the differences of brain activity between the elderly andyoung people in resting-state brain activity (P <0.001), after alphasimcorrection (rmm=6). At last, the ALFF and fALFF results after two sample Ttest were displayed on the T1WI images, and we concerned the location of theclusters, MNI, the size of the clusters, and the activity intensity.Results: After preprocessed the rs-fMRI imaging, we deleted someimages included three young volunteers and six volunteers, because of theirhead moved.The results of ALFF:Compared with the young group, the elderly showed enhanced brainactivity in bilateral superior temporal gyrus, parahippocampal gyrus,hippocampus and uncinate process, amygdala, fusiform gyrus, cingulate gyrus,inferior temporal gyrus, temporal region, partial occipital lobe, pontine,anterior lobe of cerebellum; right superior frontal gyrus, precentral gyrus,postcentral gyrus, paracentral lobule, middle occipital gyrus,; left insula,claustrum, and the left part of corpus callosum; the weakened brain regionscontain: bilateral superior frontal gyrus, middle frontal gyrus, inferior frontalgyrus, orbital gyrus, middle temporal gyrus, fusiform gyrus, occipital lobe,anterior cingulated, posterior cingulate gyrus and bilateral precuneus;leftinferior temporal gyrus, straight gyrus, postcentral gyrus, supramarginal gyrus.These brain regions contain sulus and cistern aera.The results of fALFF:The middle-aged group compared with the young group, activityincreased in brain areas:the left inferior temporal gyrus, left superior temporalgyrus, left superior temporal gyrus; right medial frontal gyrus, rightpostcentral gyrus;the weakened brain regions: bilateral cerebellar lobe,bilateral fusiform gyrus, bilateral inferior temporal gyrus, bilateral temporalgyrus, right cerebellum, left gyrus rectus, left superior frontal gyrus.Conclusion:1In resting state, the elderly compared to the younger population, mostof the activities reduced areas are located in the default mode network, and only a few located in other brain regions, show that aging first involving theDMN.2Compared to the young, it is thought that these activity increased areasin the old people may compensatory the areas of function reduced brainregions.3Compared to the young, in the resting state, the results of the ALFFshowed increasing activity in the elderly in the cistern and sulus areas ofcistern and sulus. But there is no difference in the cistern and sulus areas ofcistern and sulus of the fALFF.