Modelling Fluid-Structure Interactions in the vestibular system of lizards.

Lacertid lizard species show a remarkable diversity in locomotion behaviours. Depending on theirhabitat and ecology, some species move in a highly dynamical and fast manner, while others arecharacterised by slow movements. Thus, their locomotor behaviours most likely pose differentdemands on their balance control. The 3 semi-circular (SC) canals of the vestibular system arecrucial in this regard, because they sense rotational accelerations of the head. Hence, wehypothesise that the vestibular system is adapted to species-specific locomotion behaviour. We willperform a comparative study of the geometrical and functional properties of the SC canals ofLacertidae.The membranous SC canals are filled with endolymph fluid that deforms a cupula and its sensorswhen accelerated angularly. We will investigate the functional morphology of the 3 interconnectedSC canals with Fluid-Structure Interaction computer models. We will thoroughly examine thefunctional consequences of the geometry (i.e. anatomy) and in vivo excitation (i.e. behaviour) onsensitivity and response time in lacertid lizards. This will facilitate future comparative studies, whichare currently unequivocal in this regard.Usually, the bony SC walls are investigated, but we will focus on the membranous walls becausethese determine the vestibular system mechanics. To facilitate future studies, we will compare thegeometry of the bony and the membranous morphology, and study the functional consequences.

Keywords:BALANCE, COMPUTATIONAL FLUID DYNAMICS, BIOLOGICAL FLUIDS, LIZARDS

Disciplines:Animal biology, Veterinary medicine