Objective To study the effect and mechanism of capillary microcirculation disturbance on intracerebral hemorrhage. Methods The loading effect of capillaries was replaced by the introduction of porous media. A microcirculation model from the capillaries to the veins was established. The appropriate mechanical boundary conditions were set up for the model by referring to various physiological conditions of human body, and the changes in blood pressure and stress of vascular wall under various conditions were simulated. Results Under normal circumstances, the whole blood pressure of the LSA was relatively low, and the pressure difference between the beginning and the end of the LSA was more obvious, and the stress of all parts of the vascular wall was at the same level. In the case of microcirculation disorder, the whole blood pressure of the LSA increased and the pressure difference between the beginning and the end of the LSA significantly decreased. The stress for each part of the vessel increased and the stress at the end of the LSA increased most significantly. Conclusions The influence of microcirculation disturbance on hemodynamics of the LSA was particularly significant. It was an important factor leading to hemorrhage of the LSA rupture. The research findings are of important theoretical and practical significance for understanding the mechanism of cerebral vascular rupture and preventing the occurrence of cerebral hemorrhage in the case of microcirculation disturbance.

Objective:To explore the differences in dynamic spontaneous brain activity in individuals with subjective cognitive decline (SCD) and its correlation with spatial navigation ability in SCD subjects.Methods:A total of 72 SCD subjects(SCD group) and 67 normal controls (NC group) matched for age, gender and education level were recruited from September 2020 to February 2023 at the Affiliated Drum Tower Hospital, Medical School of Nanjing University. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) examinations, spatial navigation tests and cognitive function assessments. The rs-fMRI time series were segmented using a sliding time window method, and statistical analyses were carried out using SPSS 26.0 software to compare the differences in the dynamic amplitude of low frequency fluctuation (dALFF) between the two groups. Correlation analysis was conducted between dALFF values in different brain regions and scale scores and spatial navigation tests.Results:Compared with the NC group, the dALFF variability in the right precuneus(0.119±0.021, 0.130±0.031) and left cuneus(0.143±0.034, 0.156±0.032) in SCD group decreased ( t=-3.41, -3.12, P<0.05, FDR corrected), and the dALFF variability in the right middle occipital gyrus(0.146±0.023, 0.137±0.020) and right angular gyrus(0.148±0.025, 0.139±0.026) increased ( t=4.51, 3.36, both P<0.05, FDR corrected). The temporal variability of dALFF in the right precuneus in SCD group was negatively correlated with egocentric spatial navigation ( r=-0.341, P=0.025), delayed allocentric spatial navigation ( r=-0.286, P=0.035) and memory function ( r=-0.332, P=0.009). The temporal variability of dALFF in the left middle occipital gyrus was positively correlated with language function ( r=0.339, P=0.015) and visuospatial function ( r=0.343, P=0.008) in SCD group. Conclusions:The temporal variability of dALFF in the right precuneus and the left middle occipital gyrus may be the neurobiological basis of cognitive decline and spatial navigation impairment in SCD subjects, and it can be used as a potential imaging marker for early identification of SCD patients.