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Hippocampal vascularization pattern exerts local and global effects on structural and functional brain integrity
Author(s) -
Vockert Niklas,
Perosa Valentina,
Ziegler Gabriel,
Schreiber Frank,
Yakupov Renat,
Spallazzi Marco,
Düzel Emrah,
Schreiber Stefanie,
Maass Anne
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.039775
Subject(s) - hippocampal formation , cognition , neuroscience , hippocampus , psychology , medicine
Background The main contributor to hippocampal blood supply is the posterior cerebral artery. Additional contribution of the anterior choroidal artery distinguishes potential dual from single hippocampal vascular supply. In a previous study on patients with cerebral small vessel disease (CSVD) and older controls by Perosa et al. (Brain, in press), dual hippocampal vascularization was functionally associated with better cognition and structurally associated with increased anterior hippocampal volumes. The CSVD patients showed declined cognitive abilities. However, dual supply was able to alleviate performance loss in CSVD patients, indicating resilience against pathology. We examined the effect of dual vascular supply on anterior/posterior hippocampal volume and global grey matter (GM) volume, which might mediate the beneficial effect on cognition, and whether it conveys resistance against CSVD. Methods 47 subjects (71±8yrs) with/without CSVD (20/27) underwent 7T time‐of‐flight MRA for categorization of hippocampal vascularization pattern (HVP) and 3T T1‐weighted structural MRI. As measure of global cognitive function we focused on the MoCA. Automatic segmentations of the anterior and posterior hippocampus were obtained via the ASHS (Automatic Segmentation of Hippocampal Subfields) 3T T1 atlas. GM volumes were obtained by segmentation in SPM (Statistical Parametric Mapping). The effect of the HVP and CSVD on structural and cognitive measures was estimated using ANCOVAs. A mediation effect of GM volume on cognition was examined via bootstrapping. Fisher’s exact test assessed contingency of the observed pattern to both clinical groups to make inferences about resistance against CSVD. Results A region‐based approach revealed a greater bilateral anterior (but not posterior) HC volume and increased global GM volume in the dual supply group. In a mediation analysis, GM volume offset the effect of the HVP on the MoCA score, whereas bilateral anterior HC volume did not. While the HVP seems to convey some resilience against CSVD, no evidence for resistance against CSVD was found. Conclusions Previous findings of structural effects on anterior HC volume via VBM were confirmed. Besides its local effects, dual hippocampal vascular supply exerts global effects on brain structure. These effects partially account for better cognitive performance of the corresponding individuals. An int42708eraction with pathology might be restricted to resilience, but not resistance.