Spring 2015 Newsletter | Biology | Marquette University

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DR. JAMES BUCHANAN – MU FACULTY 1989-PRESENT

Dr. James BuchananIf you ask someone where in the nervous system the neural rhythm of walking originates, they are likely to say, “in the brain”, or, if they know something about the nervous system, “in the motor cortex.” But they would be wrong. In all vertebrates, including humans, the neural rhythm of walking and other forms of locomotion originates in the spinal cord. Understanding the cellular and synaptic mechanisms of the neural network for locomotion has been the focus of my research for most of my career, including 25 years at Marquette.

I was inspired to study the nervous system, and especially the generation of motor patterns, by an undergraduate class in linguistics I took while majoring in Biology at Colorado College (BA, 1976). Speech is a complex motor pattern, and I thought that perhaps we can better understand this uniquely human behavior by studying the basic principles of motor systems. I did my PhD in Neural Sciences at Washington University in St. Louis, MO (1981) in the lab of Carl Rovainen. This was my introduction to the lamprey, a primitive jawless vertebrate, which diverged from Dr. Buchananother vertebrates some 550 million years ago. The lamprey has a nervous system organized like our own but is small enough to survive when isolated in a dish of saline, and the isolated nervous system can exhibit the neural correlates of several behaviors. It still amazes me today to witness the beautifully-coordinated, clock-like rhythm of swimming activity in motor nerves of the isolated spinal cord of the lamprey in the absence of brain, muscles, and sensory feedback. Echoing the themes of Neil Shubin in his recent book and PBS series, Your Inner Fish, we humans have the core of the ancient lamprey locomotor network in our spinal cords, and this network drives the rhythmic activity of our muscles during walking. The motivation for my research is that by studying this simpler, more elemental form of the locomotor network in lamprey, we have a better chance to understand the cellular mechanisms underlying locomotion in all vertebrates, and perhaps the fundamental principles of motor patterns in general.

Following graduate school, I was eager to return to my home state of Colorado, so I did postdoctoral research at Colorado State University in Ft. Collins (1982-1985) where I examined spinal regeneration in rodents. I then returned to my main research interest in lamprey locomotion by working in the lab of Sten Grillner at the Karolinska Institute in Stockholm, Sweden (1985-1987). When I completed my postdoctoral position in Sweden, I spent 3 months traveling with a daypack across Europe, Russia, and China. Upon returning to the US, I worked as an Instructor and researcher at the University of Texas Medical Branch (UTMB) in Galveston, TX until coming to Marquette in 1989. It was at UTMB that I met my future wife, Maria Isabel Noguerón, an accomplished scientist and teacher from Mexico City.

At Marquette, I have had the help of many energetic and talented undergraduate and graduate students. There have been about 50 undergraduates during my time at Marquette who have done significant research work in my lab as part of independent study projects, our summer research programs, the McNair summer program, or as paid student workers. Many of these students have gone on to careers in medicine or research.

Dr. James Buchanan

The graduate students that worked in my lab at Marquette began with Dan Meer (MS, 1994) and Chis Kemnitz (PhD, 1996). Dan showed the importance of a calcium-activated potassium current in regulating neuronal firing and in fictive swimming. Chris thoroughly characterized the modulatory effects of dopamine on locomotion at the cellular, synaptic, and behavioral levels. Mark McDonald (MS, 1998) continued Chris’s work to showpresynaptic inhibition of excitatory synapses by dopamine. For his PhD with Steve Merrill in the Marquette Math Department, Wang Xu (1996) did a dynamical systems analysis of our proposed locomotor network in the lamprey. Michelle Martin (PhD, 2000) investigated the changes in neural properties that occur as neurons go from quiescence to locomotor activity. James Einum (PhD, 2004) characterized several new classes of lamprey spinal neurons that provide feedback signals to the brain during locomotion. Kathy Quinlan (PhD, 2004), who had done a research project in my lab as an undergraduate, investigated the actions of acetylcholine on the locomotor network. Peter Placas (MS, 2009), who also had done research in my lab as an undergraduate, demonstrated that electrical synapses play a significant role in the locomotor network of lamprey.

Dr. James Buchanan

My current project focuses on a group of motor neurons at the brainstem-spinal cord junction in lamprey. These cells innervate several muscles of the head of the lamprey and are involved in swimming as well as in the control of steering. These motor neurons are likely the antecedents of motor neurons in higher fish that innervate the pectoral fins and of motor neurons in tetrapods that innervate the forelimbs. This project grew out of a semester-long internship in my lab by an undergraduate from Exercise Science, Spencer Murphy, who graduated in 2011.

One of the great appeals of working at Marquette in the Department of Biological Sciences is the balance of research with teaching. I have enjoyed teaching both lab and lecture courses. At the undergraduate level, I first taught a physiology laboratory course for Physical Therapy students for 4 years before switching to the lecture course in neurobiology, which I taught for the next 18 years (minus a couple of sabbaticals). For the past 4 years, I’ve enjoyed teaching the experimental neurobiology lab course.

Outside the lab and classroom, I enjoy a variety of locomotor pursuits including hiking, biking, cross-country skiing, and canoeing here in Wisconsin and back in Colorado.

 

 

 

 

 

 

 

 

 

 

 


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