Fluid‐structure interaction simulation of balance sensation in the avian lumbosacral organ

Abstract

The lumbosacral organ (LSO) is an enlargement of the avian spinal cord hypothesized to play a role in balance sensation. Several lines of anatomical and neurophysiological evidence suggest that the LSO is directly integrated with spinal motor circuits, independent of the vestibular system. However, no model currently exists to explain its physiological function. We hypothesized that mechanosensors may respond to differential strain in spinal ligaments. We segmented iodine‐enhanced CT scans of the quail LSO to visualize the 3D anatomy of the structure. We then utilized two‐way fluid structure interaction simulations to model possible balance sensing function. Our modeling suggests that the LSO spinal ligaments are able to sense the directionality of an applied balance perturbation in the form of differential strain patterns. Furthermore, given anatomical constraints, it is unlikely that fluid velocity alone is sufficient to cause deformation in the spinal tissue. Inertia of the fluid and soft tissue itself play significant roles in generating the ligament strain. This work is the first simulation study of the LSO in any species and provides a methodological framework for further fluid dynamics modeling of the system. Our 3D reconstruction suggests potential anatomical constraints on fluid flow and supports the ligament strain hypothesis of balance sensing function. Higher resolution simulation work, as well as experimental validation studies in live animals are needed to more precisely evaluate the hypotheses for balance sensation in the LSO.Support or Funding InformationThis work was made possible by support from the American Physiological Society and the National Science Foundation Integrative Organismal Systems Award (Award No. IOS‐1238831).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.