An old dinosaur learning new tricks

Okay, so I’m the “old dinosaur” here, although I was informed recently that I could still pass as a graduate student.

I am happy to report that I am back on the campus of Brown University this week with one of my undergraduates, Radha Varadharajan, to begin what I hope to be the first in a long series of studies on the evolution of amniote (reptile, bird, mammal) forelimb posture.  We (my “rat pack” students and I) are using the XROMM technology I have detailed here on this blog to understand how the three-dimensional movements of the forelimb bones of rats actually occur.  The long-term goal of this initial study is to document how these movements facilitate hand placement and posture, and how these details of locomotion are related to bone shape.  My ultimate goal is to use the somewhat primitive forelimb posture of rats as a template to understand how some early fossil mammals may have moved.

Today, Radha and I, under the tutelage of Dr. Elizabeth Brainerd, began the process of setting up the so-called C-arm fluoroscopes that will allow us to take calibrated X-ray movies of a number of rats as they walk, run, and perhaps do other activities that we happen to capture.  This was especially exciting and informative for me, because these are the “new tricks” this “old dinosaur” wants to learn.  Tomorrow, we begin in earnest filming the skeletal movements of the rats.

You will notice in the pictures posted here that Radha and I are suited up in lead aprons and thyroid collars because, as you might anticipate, we do not want to expose ourselves to X-ray radiation during the data capture.  In fact, she and I have participated in numerous safety trainings and tests to ensure we stay safe.

Here I am behind the two C-arm fluoroscopes.  In front of the scopes, you can spy the wooden plank walk-way for the rats, and an acrylic box that the rats will walk or run through in the vicinity of the X-ray fields.

Here I am behind the two C-arm fluoroscopes. In front of the scopes, you can spy the wooden plank walk-way for the rats, and an acrylic box that the rats will walk or run through in the vicinity of the X-ray fields.

Here is Radha learning x-ray capture at the Brown C-arms lab.

Here is Radha learning x-ray capture at the Brown C-arms lab.

We also spent time today with Dr. David Baier learning how to set up what is called a rig in the MAYA software program that will later animate the skeletons of the rats we film.  Essentially, a rig in this case means creating a joint system that can be calibrated with the X-ray films and “attached” to the 3-D bone geometry from CT-scans of the rats used in the study.  I further shook some of the rust out of my head reviewing and practicing how to import calibrated data from X-ray digital movies and syncing them with 3-D bone geometry — skills I first acquired almost one year ago during Brown’s 2012 XROMM course.

All of this setup and learning is key for me and my students, not only because we want to do the science right, but also for other reasons I shall divulge in future posts.

Everyone at Brown has once again been incredibly helpful, and I am especially indebted to Dr. Brainerd for her encouragement and help over the past year with XROMM.

Please stay tuned … this week promises to get more interesting …

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One thought on “An old dinosaur learning new tricks

  1. Pingback: Rodents of usual size and their moving skeletons | The Evolving Paleontologist

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