The “Rat Pack” Succeeds

A lot has happened in the Bonnan Lab at Stockton these past few months.

First, the “Rat Pack” as I fondly call them (Evan Drake, Kadeisha Pinkney, and Radha Varadharajan), presented their research proposals for 3-D rat locomotion and kinematics to the Northeastern Regional Vertebrate Evolution Symposium (NERVES) on March 22nd, 2013, at the New York Institute of Technology (NYIT) College of Osteopathic Medicine.  Their talks were very well received and we had excellent suggestions from colleagues and scholars.  I was especially proud of these undergraduates because they were able to give technical talks to a scientific audience having only worked with me for a few months on their projects. Bravo!

A special thank you to the Symposium’s organizers, Drs. Brian Beatty and Matthew Mihlbachler!

You can read their NERVES talk titles below.

Next, they put their collective heads together and, with my input, created a very nice poster for the 2013 NAMS Research Symposium at Stockton.

You can read their NAMS research abstract below as well.

The "Rat Pack" presented their preliminary research on rat locomotion to the 2013 NAMS Research Symposium.  Left to right: Kadeisha Pinkney, Radha Varajharadan, and Evan Drake.

The “Rat Pack” presented their preliminary research on rat locomotion to the 2013 NAMS Research Symposium. Left to right: Kadeisha Pinkney, Radha Varadharajan, and Evan Drake.

Kadeisha (left) and Radha (right) explain the joys of rat locomotion to interested students.

The “Rat Pack” attracted quite a crowd.

Last, but not least, Radha Varadharajan received the first Robert L. Fines scholarship awarded at Stockton, April 26, 2013, for her work on this research and her future career goals in veterinary medicine.  Dr. Fines is a former Stockton alumnus (1975) and is one of the premiere M.D. researchers successfully fighting pancreatic cancer.  He is the Herbert Irving Associate Professor of Medicine in the Division of Medical Oncology at the Columbia University College of Physicians & Surgeons in New York, New York.  I am honored and proud that Radha has received this award from such a prestigious alumnus.

The scholarship will allow Radha to travel with me to Brown University the week of May 20-24, where we will work with Dr. Elizabeth Brainerd and colleagues X-ray filming the rats walking, running, and landing at their XROMM C-arms facility.  Stay tuned and we’ll keep you posted on our time and research activities while at Brown.

Finally, I must acknowledge the help of our campus veterinarians, Drs. Ralph Werner and Mary Wilkes, for their efforts in helping me with the rats, as well as our animal caretaker, John Rokita, for his constant help and suggestions on rodent protocols and biology.

I feel truly grateful to have made such a jump to a new college and to already be surrounded by supportive faculty, eager students, and the chance to pursue 3-D kinematics research.

NERVES Talk Titles

Varadharajan, Radha and Bonnan, Matthew F. 2013. Exploring 3-D long bone kinematics in the White Rat (Rattus norvegicus) as a model for inferring forelimb posture in early mammals: Contribution of the scapula.>

Pinkney, Kadeisha and Bonnan, Matthew F. 2013. Exploring 3-D long bone kinematics in the White Rat (Rattus norvegicus) as a model for inferring forelimb posture in early mammals: Contribution of the humerus.

Drake, Evan and Bonnan, Matthew F. 2013. Exploring 3-D long bone kinematics in the White Rat (Rattus norvegicus) as a model for inferring forelimb posture in early mammals: Contribution of the radius and ulna.

NAMS RESEARCH SYMPOSIUM ABSTRACT

Forelimb movements in Rattus norvegicus (white rat) and their relationship to pronation: implications for early mammal forelimb posture

Varadharajan, Radha; Pinkney, Kadeisha; Drake, Evan; and Bonnan, Matthew F.

 

Rattus norvegicus (the white rat) is a therian mammal with a forelimb morphology similar to that of early non-cursorial mammals. Currently, early mammal limb posture is controversial, with reconstructions ranging from sprawling to parasagittal. With this current ambiguity, the study of forelimb shape and movements in R. norvegicus may provide a model to infer the locomotor patterns of earlier mammals.  Previous research, most notably by Jenkins (1971, 1974), indicates that the forelimb posture of rats does not follow simple, pendulum-like mechanics but rather a more complex, less-upright range of movement. For the first time, we will study the 3-D morphology and kinematics of the forelimb in R. norvegicus by utilizing three-dimensional moving X-ray animations generated through the XROMM (X-ray Reconstruction of Moving Morphology) technique.  Specifically, we will focus on the three-dimensional movements of the scapula, humerus, and antebrachium (radius and ulna), and their combined contribution to pronation (placing the hand palm-side down).  To this end, we will test three interdependent hypotheses on the contribution of each of these limb segments to pronation. For the scapula, we examined the serratus anterior, supraspinatous, infraspinatous, spinotrapezius, acromiotrapezius, and rhomboids major and minor. Data gathered on the rat scapula through literature and dissection lead to the hypothesis that this element contributes in a significant way to pronation. Specific features of the humerus distinguish the parasagittal from the sprawling stance in early fossil mammals: degree of torsion, condylar structures of the elbow joint, width of the intertubercular groove, and the relative sizes of the lesser and greater tubercles.  These features are associated with major locomotor muscles such as the pectoralis major and minor, deltoids, and pronator teres. We hypothesize that the humerus will contribute in a significant way to the pronation of the hand in the white rat. In humans, the radius can rotate about the ulna to pronate the hand because these elements are bowed, creating the space necessary to allow such movements. The pronator teres and pronator quadratus pull on the radius and rotate it about the ulna, whereas the supinator and biceps brachii act as antagonists to return the bones to a parallel position. Unlike humans, the radius and ulna of Rattus norvegicus fit tightly together like two spoons stacked together, with little, if any, space available in which the radius can rotate about the ulna.  Moreover, the pronator quadratus has not yet been described or identified in our rat dissections. Instead, the radius and ulna appear “fused” by the interosseous membrane and rendered incapable of supination. Rats have little need to supinate the forelimb because the forelimbs are primarily used in locomotion. It is therefore hypothesized that all pronation and supination occur in the humerus and scapula in rats because the radius and ulna are in such close proximity to each other that we infer they participate little, if any, to pronation.  After we capture the three-dimensional movements of these bones with XROMM, we will test our hypotheses and perhaps gain insight into the posture of early mammals.

Advertisements

2 thoughts on “The “Rat Pack” Succeeds

  1. Pingback: Academic “evolution” | The Evolving Paleontologist

  2. Pingback: An old dinosaur learning new tricks | The Evolving Paleontologist

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s