Meeting Abstract

53.5  Thursday, Jan. 6  Building a virtual biomechanical model of the Bullfrog skeleton UYENO, Theodore A*; GILLES, Benjamin; SUEDA, Shinjiro; LEE, David; WILKINSON, Kit; GISZTER, Simon F. ; PAI, Dinesh K.; NISHIKAWA, Kiisa C. ; NAU; UBC; UBC; UNLV; NAU; Drexel Univ.; UBC; NAU ted.uyeno@nau.edu

In developing a quantitative understanding of bullfrog motor control, we are building an accurate computer model of the underlying musculoskeletal plant. We began by creating a high-resolution virtual model of the bullfrog skeleton. First, a template model of the skeleton was developed using a GE lightspeed VCT scanner. This model was low resolution (512x512x302 slices, 350x350x625 μm resolution), but the large specimen was posed in a natural resting position during scanning. Using a Viva CT 40 micro CT scanner, we then made high-resolution scans (1024x1024x2222 slices, 45x45x45 μm resolution) of smaller, preserved frogs that were compressed to fit into the bore. We manually defined the bone segments for the template model and then used it to automatically segment each of the bones in the high-resolution model. We then developed algorithms to register the 3D positions of the high-resolution bones to the locations of the template bones. This resulted in a high-resolution skeleton model in a natural resting position. Next, using high-speed biplanar light and X-ray videography, we measured joint parameters, including the degrees of freedom and ranges of motion. These were used to define a tree structure called a kinematic skeleton that realistically links the bone segments of the high-resolution skeleton model. We recorded high-speed videos of feeding lunges, and registered the high-resolution kinematic skeleton to points identified in the biplanar X-ray videos in order to precisely characterize the movement of the bullfrog skeleton during the lunges. These visualizations were 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.