David S. K. Magnuson, Ph.D.
Associate Professor, Departments of Neurological Surgery and Anatomical Sciences & Neurobiology
Research Description
The research in my laboratory is focused on the neurons and pathways in the spinal cord that are responsible for locomotion, and on applying what we learn about locomotor systems to spinal cord injury and repair.
One of our primary investigations is focused on the long propriospinal neurons and pathways in the spinal cord that link the lumbar and cervical enlargements. These circuits are well-suited to participate in locomotion and are thought to mediate forelimb/hindlimb coordination in animals and upper-body/arm movement during walking and running in humans. We use a combination of approaches including electrophysiology and tract-tracing and both the in vitro neonatal rat brainstem/spinal cord preparation, in vitro, and adult rats, in vivo. We are seeking to determine the roles played by specific descending and ascending pathways in locomotor activity in normal and spinal cord injured rats. The most recent results from this project suggest that white matter in the lateral and ventrolateral funiculus of the spinal cord may carry ascending and descending propriospinal axons that terminate in the cervical and lumbar enlargement, respectively. Many of these axons are located in the outermost rim of white matter and are spared following contusion spinal cord injuries, making them excellent potential targets for therapeutic approaches following spinal cord injury.
A second major project in my laboratory is aimed at gaining a better understanding of activity-based rehabilitation, one of the primary rehabilitation strategies used clinically, that usually takes the form of body-weight supported treadmill training. We are currently using four different approaches in animal models including swimming, shallow water walking, treadmill step training with body-weight support and a rat wheel-chair to reduce hindlimb movement after injury. Over the next several years we will be investigating the mechanisms underlying functional recovery following activity-based rehabilitation including the role(s) that cutaneous feedback, limb-loading, step-cycle number and frequency and timing and duration of training play in a successful rehabilitation program. We are working with Dr. Susie Harkema, the director of the NeuroRehabilitation Program at the Frazier Rehabilitation Institute to answer specific questions in the animal model that will assist with the development of novel clinical rehabilitation strategies.
In addition, we are working with the laboratories of Drs. Scott Whittemore, Susan Harkema, Qilin Cao and Richard Benton within KSCIRC, Dr. Michael Voor in Orthopedic Surgery at UofL, David Loy and Victor Song at Washington University and Jorge Miranda at the University of Puerto Rico.
Current Laboratory Personnel:
Dr. Rebecca Smith (Postdoc)
Krista Caudle (PhD student)
Jon Kuerzi (Recent MSc graduate)
Alice Shum-Siu (Research Associate)
Victoria Druzhinina (Research Technician)
Ashley Whelan (Research Technician)
Eddie Brown (Research Associate)
Personnel of the Electrophysiology and Behaviore Core:
Darlene Burke (Research Coordinator) Behavioral assessment and statistics.
Kim Fentress (Research Technician) Electrophysiological assessment.
Johnny Morehouse (Research Technologist) Kinematics
Personnel of the Surgery and Animal Care Core:
Aaron Puckett (Research Technician)
Christine Nunn (Research Technologist)