Abnormal amplitude of low-frequency fluctuations of intrinsic brain activity in Alzheimer's disease.
We used resting-state functional magnetic resonance imaging to measure the amplitude of low-frequency fluctuations (ALFF) of intrinsic brain activity in 23 patients with moderate Alzheimer's disease (AD) and 27 age- and gender-matched healthy controls. Two different frequency bands were analyzed (slow-5:0.01-0.027 Hz; slow-4:0.027-0.073 Hz). In many brain regions, widespread ALFF differences between the two frequency bands were observed, including predominantly the posterior cingulate cortex/precuneus (PCC/PCu), hippocampus/parahippocampal gyrus (Hip/PHG), insula, thalamus, and basal ganglia. Compared to controls, AD patients showed decreased ALFF values in the bilateral PCC/PCu, inferior parietal lobe, and several temporal regions, and increased ALFF values mainly in the bilateral Hip/PHG, and middle and inferior temporal gyri. Intriguingly, the ALFF abnormalities in the left PCu, left supramarginal gyrus, and several temporal regions were greater in the slow-5 band compared to the slow-4 band. Moreover, correcting for gray matter volume loss significantly affected the functional analytical results, suggesting that gray matter loss can partially account for the functional imaging analytical results obtained in AD. Finally, we showed that regions with changes in ALFF demonstrated a significant correlation with patient cognitive performance as measured using Mini-Mental State Examination scores. The results also demonstrated a significant correlation between hippocampal volume and the ALFF in slow-5 band in the AD group. This study demonstrated widespread ALFF abnormalities of intrinsic brain activity in AD and revealed that the ALFF abnormalities in severe specific regions were frequency-dependent. Taken together, our findings provided novel insights into the pathophysiological mechanism of AD and may be helpful in the development of imaging biomarkers for disease diagnosis.
Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China.
Xuena
X
Liu
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China.
Siqi
S
Wang
Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China.
Xinqing
X
Zhang
Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing, China.
Zhiqun
Z
Wang
Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China.
Xiaojie
X
Tian
State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, China.
Yong
Y
He
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D016022:Case-Control Studies; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D013223:Statistics as Topic
D010100:Oxygen
Alzheimer's disease; amplitude of low-frequency fluctuation; intrinsic brain activity; resting-state functional magnetic resonance imaging