Age-Related Changes in Structure and Perfusion of Hippocampal Subfields and Connected Cortex
Poster No:
924
Submission Type:
Abstract Submission
Authors:
Yulin Ge1, Chenyang Li1, Jiaqi Wen1, Jiangyang Zhang2
Institutions:
1NYU Langone Health, New York, NY, 2NYU School of Medicine, New York, NY
First Author:
Co-Author(s):
Introduction:
As a primary structure affected by aging, the hippocampus and its subfields undergo tissue loss and diminished perfusion, which might contribute to cognitive decline and increased vulnerability to dementia. However, the relationship between hippocampus structure and vascular function remains unclear. Previous studies have demonstrated that the hippocampus connects with the prefrontal and entorhinal cortex through neural circuits, playing an essential role in cognitive processes [1]. Additionally, hormonal changes in older women may heighten their vulnerability to aging [2], emphasizing the need to investigate sex-specific patterns in the aging of these interconnected regions. Arterial spin labeling (ASL) can provide estimates of cerebral blood flow (CBF) and arterial transit time (ATT), serving as functional biomarkers that can detect early changes in vascular function [3]. In the current study, T1-weighted and ASL data from 540 subjects in the Human Connectome Project - Aging (HCP-Aging) dataset [4] were utilized to explore the relationship between structural and vascular functional alterations in the hippocampus subfield and connected prefrontal and entorhinal cortex, as well as their influence on cognition during healthy aging.
Methods:
The prefrontal and entorhinal cortex were segmented using the FreeSurfer pipeline based on T1-MPRAGE data. The segmentation of hippocampus subfields, including subiculum, CA1-4, and dentate gyrus was performed using Hippfold toolbox [5] (Fig. 1B). CBF and ATT in hippocampal subfields was unfolded and projected into the hippounfolded space to acquire subfield-specific values (Fig. 1D, E). For the ASL data, a multiple post-labeling delay (PLD) and a simultaneous multi-slice acquisition (SMS) pseudo-continuous ASL (pCASL) protocol were employed with the following parameters: labeling duration of 1500 ms, PLDs: 200 ms, 700ms, 1200ms, 1700ms, and 2200ms, each PLD was repeated 6, 6, 6, 10, and 15 times, respectively, and multiband factor of 6. The voxel size was 2.5mm isotropic with a total of 60 slices. The mb-PCASL data was preprocessed using hcpasl minimal processing pipeline (https://github.com/physimals/hcp-asl) to yield CBF and ATT maps (Fig. 1A, C). Total cognitive composite scores were used to reflect overall cognition. Statistical analysis was performed in GraphPad Prism and SPSS with p value < 0.05 as statistically significant.
Results:
As age increases, as shown in Figure 2, the volumes of the prefrontal cortex decrease, ATT delays, and CBF declines (Pfemale<0.05, Pmale<0.05); the entorhinal cortex only exhibits a decrease in volume (Pfemale<0.05, Pmale<0.05) and a decline in CBF in females (Pfemale=0.003). All hippocampal subfields show a decrease in volume and a delayed ATT with age (Pfemale<0.05, Pmale<0.05), whereas a decrease in CBF was not found in the subiculum (Pfemale=0.131, Pmale=0.177), and CA4 in males (Pmale=0.189) (Fig. 2). The volumes of the hippocampal subfields are negatively correlated with ATT (Pfemale<0.05, Pmale<0.05), except for subiculum (Pmale=0.091), CA1 (Pmale=0.053), and CA2 (Pmale=0.642) in males. The volumes of hippocampal subfields are positively correlated with CBF only in CA1 (Pfemale<0.001, Pmale=0.033), as well as CA3 (Pfemale=0.028) and DG (Pfemale=0.046) in females. Correlations among volumes, ATT, and CBF in the prefrontal and entorhinal cortex, hippocampus, and its subfields are more pronounced in females compared to males.
Conclusions:
Our study revealed the relationship between structure and vascular function in the hippocampus and connected prefrontal and entorhinal cortex, revealing sex- and subfield-specific trajectories with age. A deeper understanding of these relationships could offer deep insights into the mechanisms underlying age-related neurodegenerative diseases such as Alzheimer's.
Lifespan Development:
Aging 1
Modeling and Analysis Methods:
Image Registration and Computational Anatomy
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Cortical Anatomy and Brain Mapping
Cortical Cyto- and Myeloarchitecture
Physiology, Metabolism and Neurotransmission:
Cerebral Metabolism and Hemodynamics 2
Keywords:
Aging
Cerebral Blood Flow
Memory
MRI
NORMAL HUMAN
STRUCTURAL MRI
1|2Indicates the priority used for review
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4. Bookheimer S.Y. (2019). The Lifespan Human Connectome Project in Aging: An overview. NeuroImage, 185:335-348.
5. Harms M.P. (2018). Extending the Human Connectome Project across ages: Imaging protocols for the Lifespan Development and Aging projects. NeuroImage, 183:972-984.