3D models using artificial intelligence for anatomical research – ScienceDaily

There was a time, not so long ago, when scientists like Casey Holiday needed scalpels, scissors, and even their own hands to do anatomical research. But now, with recent advances in technology, Holliday and colleagues at the University of Missouri are using artificial intelligence (AI) to see inside an animal or person — right down to a single muscle fiber — without making any cuts.

Holliday, an associate professor of pathology and anatomical sciences, said his lab at MU School of Medicine is one of only a handful of labs in the world currently using this high-tech approach.

AI can teach computer programs to identify muscle fibers in an image, like a computed tomography scan. Then, researchers can use this data to develop detailed 3D computer models of the muscles to better understand how they work together in the body to control motors, Holiday said.

Holliday, along with some of his current and former students, did this recently when they began studying the power of crocodile biting.

“The unique thing about crocodiles’ heads is that they are flat, and most animals that have evolved to bite hard, like hyenas and lions and T. rexes and even humans have really long skulls, because all of these jaw muscles are oriented vertically,” Holliday said. “They are designed this way that they put a lot of vertical bite force into everything they eat. But the crocodile’s muscles are more horizontally oriented.”

3D models of muscle architecture can help the team determine how to orient the muscles in the crocodile’s heads to help increase its bite force. One of Holiday’s former students helped lead the effort, Caleb Sellers, now a postdoctoral researcher at the University of Chicago.

“Jaw muscles have long been studied in mammals with the assumption that relatively simple descriptions of muscle anatomy can tell you a lot about skull function,” Sellers said. “This study shows the complexity of jaw muscle anatomy in a group of reptiles.”

Holliday’s lab first started experimenting with 3D imaging several years ago. Some of their early results were published in 2019 with a study in integrative biology that showed the evolution of a three-dimensional model of skeletal muscle in European starlings.

Moving to a digital world

Historically, Holliday said anatomical research—and much of what he did while growing up—involved dissecting animals with a scalpel or scissors, or what he calls an “analog” approach. He first learned about the benefits of using digital photography to study anatomy when he joined the “Sue the T. rex” project in the late 1990s. To date, it remains one of the largest and most well-preserved specimens of Tyrannosaurus rex ever discovered.

Holiday remembers the moment the giant T. rex skull was taken to Boeing’s Santa Susana Field Laboratory in California to be photographed in one of the airline’s massive CAT scanners typically used to scan jet engines on commercial aircraft.

“At the time, it was the only scanner in the world that was large enough to fit in the skull of a T. rex, and also had the power to push X-rays through rocks,” said Holiday. “After I got out of college I had considered becoming a radiology technician, but with Project Sue I was learning all about how to CAT scan this thing, and that really caught my eye.”

Nowadays, Holliday said many of his current and former students at MU are learning to understand anatomy using “sophisticated” imaging and modeling methods that he and his colleagues have devised. One of those students is Emily Lesnar, a MU graduate who developed her passion for “long-dead animals” by working in the Holiday Lab.

“The digitization process is not only beneficial to our lab and our research,” Lesnar said. “It makes our work shareable with other researchers to help accelerate scientific progress, and we can also share it with the public as educational and conservation tools. Specifically, my work researching the interconnected soft tissues and bones in these animals has not only resulted in hundreds of future questions that must be answered. on it, but also revealed many unknowns. In this way, I not only gained photography skills to help with my future work, but I now have more than just professional avenues to explore.”

Holliday said plans are also underway to take their 3D anatomical models a step further by studying how human hands evolved from their evolutionary ancestors. The project, which is still in its early stages, recently received a grant from the Leakey Foundation. Holliday will be joined on the project by two of his colleagues at MU, Carol Ward, curators distinguished professor of pathology and anatomical sciences, and Kevin Middleton, associate professor of biological sciences.

While about 90% of the research done in Holliday’s lab involves studying things found in the modern world, he said the data they collect could also inform the fossil record, such as additional knowledge about how T. rex moved and worked.

“By knowing better about actual muscle anatomy, we can really learn how T. rex birds can actually make fine motor controls, and more precise behaviors, such as bite force and feeding behavior,” Holiday said.