TY - JOUR T1 - The Presence of the Temporal Horn Exacerbates the Vulnerability of Hippocampus during Head Impacts JF - bioRxiv DO - 10.1101/2021.12.07.471634 SP - 2021.12.07.471634 AU - Zhou Zhou AU - Xiaogai Li AU - August G Domel AU - Emily L Dennis AU - Marios Georgiadis AU - Yuzhe Liu AU - Samuel J. Raymond AU - Gerald Grant AU - Svein Kleiven AU - David Camarillo AU - Michael Zeineh Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/12/09/2021.12.07.471634.abstract N2 - Hippocampal injury is common in traumatic brain injury (TBI) patients, but the underlying pathogenesis remains elusive. In this study, we hypothesize that the presence of the adjacent fluid-containing temporal horn exacerbates the biomechanical vulnerability of the hippocampus. Two finite element models of the human head were used to investigate this hypothesis, one with and one without the temporal horn, and both including a detailed hippocampal subfield delineation. A fluid-structure interaction coupling approach was used to simulate the brain-ventricle interface, in which the intraventricular cerebrospinal fluid was represented by an arbitrary Lagrangian-Eulerian multi-material formation to account for its fluid behavior. By comparing the response of these two models under identical loadings, the model that included the temporal horn predicted increased magnitudes of strain and strain rate in the hippocampus with respect to its counterpart without the temporal horn. This specifically affected cornu ammonis (CA) 1 (CA1), CA2/3, hippocampal tail, subiculum, and the adjacent amygdala and ventral diencephalon. These computational results suggest the presence of the temporal horn is a predisposing factor for the prevalence of hippocampal injury, advancing the understanding of hippocampal injury during head impacts. A corresponding analysis in an imaging cohort of collegiate athletes found that temporal horn size negatively correlates with hippocampal volume in the same subfields, suggesting a possible real-world correlation whereby a larger temporal horn may be associated with decreased hippocampal volume. Our biomechanical and neuroimaging effort collectively highlight the mechanobiological and anatomical interdependency between the hippocampus and temporal horn.Competing Interest StatementThe authors have declared no competing interest. ER -