Examining hippocampal vessel distances in relation to cognition and brain structure in young adults
Poster No:
2282
Submission Type:
Abstract Submission
Authors:
Niklas Vockert1, Lilli Lümkemann2, Yeo-Jin Yi1, Berta Garcia-Garcia1, Niklas Behrenbruch1, Jonas Marquardt1, Dayana Hayek3, Hendrik Mattern4, Dorothea Hämmerer1, Nadine Diersch1, Esther Kühn3, Stefanie Schreiber2, Anne Maass1
Institutions:
1German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany, 2Department of Neurology, Otto-von-Guericke-University, Magdeburg, Germany, 3German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany, 4Biomedical Magnetic Resonance, Otto-von-Guericke-University, Magdeburg, Germany
First Author:
Co-Author(s):
Introduction:
The hippocampus is a region with particular vulnerability to hypoxia (Spielmeyer, 1925; Uchimura, 1928). A contribution of the anterior choroidal artery (AChA) to hippocampal blood supply (dual supply) and closer proximity of the hippocampus to its surrounding vessels have been associated with better cognitive performance (Perosa et al., 2020; Vockert et al., 2021; Garcia-Garcia et al., 2023). A dual supply has further been related to greater structural integrity in the anterior medial temporal lobe (MTL) and throughout the whole brain. As these findings have been made in a cohort of older adults, including patients with cerebral small vessel disease, it is yet unknown if better hippocampal vascularization exerts its structural and cognitive benefits in late life or conveys a source of reserve already in early adulthood.
Methods:
29 young adults (age=23.5±2.6 years, 58.6% female) underwent 7T MRI (T1-weighted sequence, T2-weighted sequence optimized for MTL volumetry, time-of-flight (ToF) angiography) and cognitive testing. Manual segmentation of the AChAs, posterior cerebral arteries (PCAs) and posterior communicating arteries was performed on the ToF images. Two vascular metrics of interest were calculated in MNI space. First, an average distance of the hippocampus (defined by a generic MNI mask from Freesurfer) to its closest surrounding vessels was calculated (mean hippocampal vessel distance = HVD). Second, the distances of the centers of mass from the hippocampus to the PCA and AChA main trunks, respectively, were combined in a root-mean-square fashion to form the center of mass distance (CoMD). Grey matter and white matter volumes (cumulative probabilities) were obtained as global brain structural measures via SPM tissue segmentation of the T1-weighted images. Anterior and whole hippocampus volumes as local structural measures were acquired from the T2-weighted images after segmentation with ASHS. As cognitive measures of interest a composite memory score (summed z scores of selected memory tests) and a global cognitive performance factor score (principal component analysis) were obtained from tests spanning multiple cognitive functions (e.g. Rey Figure, TMT, SDMT, Stroop). Linear models were utilized to investigate a relationship between the two vessel metrics (bilaterally averaged) and the cognitive as well as global structural measures. Total intracranial volume (for structural outcomes), sex and years of education were used as covariates. Linear mixed effects models with a subject-specific intercept examined the relationship between vessel metrics and the unilateral local structural measures with hemisphere as an additional covariate.
Results:
Smaller distances between the hippocampus and its surrounding vessels (HVD) tended to co-occur with greater anterior (p = 0.065) and whole hippocampus volumes (p = 0.082). There was no evidence that a closer distance to the surrounding vessels was related to global structural nor cognitive measures (all p values > 0.1). Neither was there evidence for a relationship between CoMD and any structural nor cognitive measures.
Conclusions:
Unlike in older adults with CSVD, we found no evidence that smaller distances between the hippocampus and its surrounding vessels are related to better cognitive performance in young adults. On a structural level, larger hippocampi tended to be found in young adults with smaller average HVDs. Given the previously observed relationship between mean HVD and cognitive performance in older adults, one might hypothesize that larger hippocampal volumes in young adults provide individuals with smaller HVD with more neurobiological capital to lose in the face of aging and disease (brain reserve). These individuals might then develop cognitive deficits later than their peers. However, this requires further investigation and does not exclude the possibility that individuals with a better blood supply are able to maintain their brain structure and cognitive abilities better.
Learning and Memory:
Long-Term Memory (Episodic and Semantic) 2
Lifespan Development:
Early life, Adolescence, Aging
Novel Imaging Acquisition Methods:
Anatomical MRI 1
Multi-Modal Imaging
Keywords:
HIGH FIELD MR
Memory
MR ANGIOGRAPHY
STRUCTURAL MRI
Other - Brain Vascularization
1|2Indicates the priority used for review
Provide references using author date format
Perosa, V. (2020), 'Hippocampal vascular reserve associated with cognitive performance and hippocampal volume' Brain, vol 143, no. 2, pp. 622-634
Spielmeyer, W. (1925), 'Zur pathogenese örtlich elektiver gehirnveränderungen', Zeitschrift für die gesamte Neurologie und Psychiatrie, vol. 99, no. 1, pp. 756-776
Uchimura, J. (1928), 'Über die Grefäßversorgung des Ammonshornes', Zeitschrift für die gesamte Neurologie und Psychiatrie, vol. 112, no. 1, pp. 1-19
Vockert, N. (2021), 'Hippocampal vascularization patterns exert local and distant effects on brain structure but not vascular pathology in old age', Brain Communications, vol. 3, no. 3