JAMES T. BUCHANAN
Wehr Professor

B.A. 1976, Colorado College
Ph.D. 1981, Washington University
Postdoctoral Fellow, Colorado State University and Karolinska Institute (Sweden)

WLS B02
(414) 288-1482
email: james.buchanan@marquette.edu

Neurobiology of Locomotion

This laboratory is concerned with understanding the principles governing the operation of neuronal networks. The network of interest is that generating swimming in the spinal cord of the lamprey, a primitive vertebrate fish. The lamprey spinal cord is advantageous for network studies because of its relative simplicity and its ability to survive for several days in vitro. The isolated, living spinal cord exhibits the neuronal correlate of swimming, and individual nerve cells can be observed and studied with a variety of electrophysiological, pharmacological, and anatomical techniques. The lamprey brainstem and spinal cord provide a model system for the study of the vertebrate central nervous system and the rules of operation of basic neural networks.
 
The activity of neuronal networks depends on interactions among several levels of organization: 1) the network level: the pattern of synaptic connections among the neurons, 2) the synaptic level: the sign, the strength, and the temporal and dynamic properties of the synaptic connections, and 3) the cellular level: the membrane properties that affect how the neurons respond to synaptic inputs. In addition to studying the basic rhythm generating mechanisms at these three levels, we are also investigating how the locomotor network is controlled by the brain, how the spinal cord informs the brain of locomotor activity, and how various neuromodulatory substances alter the properties and patterns of the locomotor network.
 
Selected References  
Buchanan, J.T. 2001. Contributions of identifiable neurons and neuron classes to lamprey vertebrate neurobiology. Prog. Neurobiol. 63:441-466.
 
Einum, J.F. and Buchanan, J.T. 2004. Reticulospinal neurons receive direct spinobulbar inputs during locomotor activity in lamprey. J. Neurophysiol. 92: 1384-1390.

Quinlan, K.A., Placas, P.G., and Buchanan, J.T. 2004. Cholinergic modulation of the locomotor network in the lamprey spinal cord. J. Neurophysiol. 92: 1536-1548.

Einum, J.F. and Buchanan J.T. 2005. Membrane potential oscillations in reticulospinal and spinobulbar neurons during locomotor activity. J. Neurophysiol. 94: 273-281.

Einum, J.F. and Buchanan, J.T. 2006. Spinobulbar neurons in lamprey: Cellular properties and synaptic interactions. J. Neurophysiol. 96: 2042-2055.

Buchanan, J.T. and Einum, J.F. 2007. The spinobulbar system in lamprey. Brain Research Reviews, in press. http//dx.doi.org/10.1016/j.brainresrev.2007.07.010.

Current Graduate Students
M.S.

• Peter G. Placas

Recent Graduate Students

• James F. Einum, Ph.D., May 2004; currently at University of Montreal, Canada
• Katharina A. Quinlan, Ph.D., May 2004; currently at Northwestern University, Chicago, IL