Mechanical behavior of the hippocampus and corpus callosum: An attempt to reconcile ex vivo with in vivo and micro with macro properties

Bertalan G, Becker J, Tzschätzsch H, Morr A, Herthum H, Shahryari M, Greenhalgh RD, Guo J, Schröder L, Alzheimer C, Budday S, Franze K, Braun J, Sack I (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Journal of the Mechanical Behavior of Biomedical Materials Elsevier

Book Volume: 138

Article Number: 105613

DOI: 10.1016/j.jmbbm.2022.105613

Abstract

Mechanical properties of brain tissue are very complex and vary with the species, region, method, and dynamic range, and between in vivo and ex vivo measurements. To reconcile this variability, we investigated in vivo and ex vivo stiffness properties of two distinct regions in the human and mouse brain - the hippocampus (HP) and the corpus callosum (CC) - using different methods. Under quasi-static conditions, we examined ex vivo murine HP and CC by atomic force microscopy (AFM). Between 16 and 40Hz, we investigated the in vivo brains of healthy volunteers by magnetic resonance elastography (MRE) in a 3-T clinical scanner. At high-frequency stimulation between 1000 and 1400Hz, we investigated the murine HP and CC ex vivo and in vivo with MRE in a 7-T preclinical system. HP and CC showed pronounced stiffness dispersion, as reflected by a factor of 32–36 increase in shear modulus from AFM to low-frequency human MRE and a 25-fold higher shear wave velocity in murine MRE than in human MRE. At low frequencies, HP was softer than CC, in both ex vivo mouse specimens (p < 0.05) and in vivo human brains (p < 0.01) while, at high frequencies, CC was softer than HP under in vivo (p < 0.01) and ex vivo (p < 0.05) conditions. The standard linear solid model comprising three elements reproduced the observed HP and CC stiffness dispersions, while other two- and three-element models failed. Our results indicate a remarkable consistency of brain stiffness across species, ex vivo and in vivo states, and different measurement techniques when marked viscoelastic dispersion properties combining equilibrium and non-equilibrium mechanical elements are considered.

Authors with CRIS profile

Christian Alzheimer Lehrstuhl für Physiologie Silvia Budday Lehrstuhl für Technische Mechanik Kristian Franze

Additional Organisation(s)

Sonderforschungsbereich 1540: Erforschung der Mechanik des Gehirns (EBM): Verständnis, Engineering und Nutzung mechanischer Eigenschaften und Signale in der Entwicklung, Physiologie und Pathologie des zentralen Nervensystems

Involved external institutions

Charité - Universitätsmedizin Berlin DE Germany (DE) University of Cambridge GB United Kingdom (GB) Deutsches Krebsforschungszentrum (DKFZ) DE Germany (DE)

How to cite

APA:

Bertalan, G., Becker, J., Tzschätzsch, H., Morr, A., Herthum, H., Shahryari, M.,... Sack, I. (2023). Mechanical behavior of the hippocampus and corpus callosum: An attempt to reconcile ex vivo with in vivo and micro with macro properties. Journal of the Mechanical Behavior of Biomedical Materials, 138. https://dx.doi.org/10.1016/j.jmbbm.2022.105613

MLA:

Bertalan, Gergerly, et al. "Mechanical behavior of the hippocampus and corpus callosum: An attempt to reconcile ex vivo with in vivo and micro with macro properties." Journal of the Mechanical Behavior of Biomedical Materials 138 (2023).

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