Meeting Abstract

P3.61  Friday, Jan. 6  Towards the automatic animation of a virtual 3D Bullfrog skeleton UYENO, T.A.*; GILLES, B.; LEE, D.V.; BARBANO, D.L.; WILKINSON, K.C.; PAI, D.K.; GISZTER, S.F.; NISHIKAWA, K.C.; Valdosta State Univ.; INRIA, Montpellier, FR; Univ. of Nevada - Las Vegas; N. Arizona Univ.; N. Arizona Univ.; Univ. of British Columbia; Drexel Univ.; N. Arizona Univ.

We are building an accurate computer model of the bullfrog musculoskeletal system in order to develop a quantitative understanding of motor control during feeding lunges, a voluntary movement that is controlled by relatively few spinal motor primitives. We have developed individual-specific, virtual skeleton models using high-resolution micro-CT imaging data (1024x1024x2222 slices, 45x45x45 ┬Ám resolution). The bones were automatically segmented by comparing them to a low-resolution, articulated, template model. Prior to euthanizing, fixing, and scanning the bones of each frog, we recorded X-ray video of six feeding lunges. To make these recordings, six frogs had up to 16 capsule-shaped, silver markers (2-5 mm x 0.81 mm diameter) implanted between the periosteum and the surface of cranial, limb, and axial bones. The frogs were allowed to recover from this surgery for at least two weeks so that the markers would be encapsulated within the fibrous sheath and immobile relative to the underlying bone. Markered frogs were trained to perform a feeding lunge within a biplanar, high speed X-ray system. We recovered kinematic data using XROMM software (, Brown University) and used both the bone shadows and the single markers on select bones to dynamically register the movements to our virtual skeleton. This was done using an adaptive algorithm that located each bone model via surface registration for each frame taken during the feeding lunge. These visualizations will be used to test the hypothesis that voluntary feeding movements are controlled by the same set of spinal motor primitives that have been identified during wiping and other movements in decerebrated frogs. Supported by IIS-0827688.