A Resting-state FMRI Study On Frequency-dependent Alterations In The Amplitude Of Low-frequency Fluctuations And Voxel-based Morphometry Brain Structual Research In Primary Insomnia

Objective: To investigate the features of resting-state brain activity in amplitude of low-frequency fluctuation(ALFF) within different band of fluctuation(Slow-4:0.027-0.073 Hz, Slow-5: 0.01-0.027Hz) in primary insomnia(PI) patients. To explore the difference of the whole brain gray matter volume(GMV) with PI in comparison with good sleepers(GS) using voxel-based morphometry(VBM) methods.Methods: 44 PI patients and 44 age-, gender-, and education-matched good sleepers(GS) were recruited and underwent resting-state functional magnetic resonance imaging scans and brain structures for three dimensional examination.1.The ALFF method processing was performed using DPARSFA(Advanced data processing assistant for resting state fMRI), ANOVA measures with condition(PI,GS) and frequency band(Slow-4, Slow-5) were performed using SPM8 to analysis the features of intrinsic brain activity, post-hoc analysis were used to observe the ALFF value between two groups in frequency bands of Slow-4 and Slow-5, and the correlations between significant ALFF values and clinical markers.2.The VBM-DARTEL method processing was performed using DPARSFA,Between-group differences(PI, GS) in gray matter volumes(GMV) were assessed by two-sample t-tests to draw significant different brain regions.Results: 1.bilateral Caudate Head,bilateral Insula,bilateral Inferior Temporal Gyrus showed higher ALFF in Slow-4(Slow-4>Slow-5, p<0.05, Alpha Sim corrected),bilateral Medial Frontal Gyrus, bilateral orbitofrontal cortex, bilateral Superior Temporal Gyrus showed higher ALFF in Slow-5(p<0.05, AlphaSim corrected).Compared with GS, PI showed decreased ALFF in the bilateral Cerebellum Posterior Lobe,left Superior Frontal Gyrus, Medial Frontal Gyrus;and increased ALFF in the left Middle Temporal Gyrus,right Superior Temporal Gyrus,bilateral Posterior Cingulate,bilateral Precuneus(p<0.05, AlphaSim corrected). Furthermore, the Slow-5frequency band are more likely to find abnormal spontaneous brain activity in PI patients.2.Compared with GS group, PI group showed higher GMV in right CerebellumPosterior Lobe, right Superior Temporal Gyrus, and lower GMV in right parahippocampal gyrus, right orbital frontal cortex and right cuneus.(p <0.001,k>50,corrected for multiple comparisons by the False discovery rate(FDR) method)Conclusions:1. PI patients had abnormal neurons intrinsic brain activity in many brain regions, especially the brain regions which are in cognitive and emotional control loop,2.PI has brain activity sensitive to specific frequency bands, and the Slow-5frequency band can be easier to find abnormal spontaneous brain activity in PI.3.We found gray matter volume alters in multiple brain regions in PI and Gray matter deficit may be associated with hyperarousal and elevated emotional reactivity.