Current Research Description

Recovery of function following injury to the central nervous system appears to be dependent on factors that include: the severity of the lesion, the type and number of spared descending systems, the type of therapeutic intervention administered and the time at which the intervention is given. Projects in my lab focus on identifying these and other factors, which affect motor recovery.

We currently use a rat model of spinal cord injury (SCI), which replicates human SCI such that a central lesion is produced which is surrounded by a rim of spared tissue. The spared tissue is comprised of axons, which ascend to and descend from the brain. We and others have shown that greater axonal sparing is associated with greater locomotor recovery. My work has focused on identifying the brain nuclei with spared descending axons, which extend below the lesion and are responsible for recovery. Several systems appear to play an important role in recovery and we are now doing a series of lesion experiments of specific brain nuclei after SCI in order to determine the role each plays in recovery. These experiments require precise behavioral analysis; therefore, we utilize two-dimensional kinematic analysis of locomotor and reflex behaviors. In this way, we are able to establish some of the neural mechanisms, which underlie motor recovery.

The second focus of the lab is to establish effective therapeutic treatments for humans with SCI. We use two approaches to meet this goal. The first is to serve as a co-investigator in a randomized clinical trial designed to examine the role of body weight supported treadmill training on recovery of overground locomotion in patients with acute SCI. This is an exciting investigation that represents the first clinical trial to determine the efficacy of neurorehabilitation treatment strategies. The second approach we use to determine effective treatments is to use a rat model of SCI to develop exercise treatments that improve gross locomotion. By relying on an animal model, we use of an animal model that enables us to use invasive procedures to determine the neural mechanisms that govern exercise-induced functional improvements. Our current efforts are directed to treadmill, swimming and standing training after SCI. In an attempt to examine all factors affecting motor recovery,  we employ extensive kinematic analysis of behavior, which we correlate to neuroanatomical analyses of the motor unit. Specifically, we determine whether improvement following exercise is accompanied by adaptations of motor neurons in the spinal cord, changes in motor and sensory peripheral nerves as well as alterations in muscle fiber type and size in the affected limbs.

In an ongoing collaboration, we are using similar techniques to investigate the neuromotor deficits that occur with aging.