Operant Conditioning Rehabilitation Studies
By Amanda Fortune
In a September episode of our “Ask the Expert: Research Edition” podcast, Krissy Dilger of SRNA was joined by Dr. Aiko Thompson, PhD, a neuroscientist and associate professor in the College of Health Professions, Medical University of South Carolina. Dr. Thompson’s research focuses on understanding central nervous system (CNS) plasticity in human sensorimotor control and how to guide the plasticity to help restore useful function in people after CNS damage. In this podcast, Dr. Thompson specifically discusses her current research on operant conditioning and its application in enhancing motor function and sensory pathways in individuals with spinal cord damage due to neuroimmune disorders, including the specifics of current studies and ongoing trials and how eligible participants can become involved.
Operant conditioning is a method to induce behavior learning based on the consequence of that behavior. That is, when the consequence of a behavior is positive, its occurrence increases, whereas if the consequence is negative, that behavior’s occurrence decreases. Dr. Thompson explains that this concept can be applied to involuntary behaviors, such as stimulus-triggered muscle responses from non-invasive brain stimulation, so the neural pathways that produce these muscle responses can be trained to be upregulated (for example, increasing strength in weak muscles) or downregulated (for example, reducing reflexes from spasticity).
In 2005, Dr. Thompson’s team hypothesized that using the approach of operant conditioning, they could change the key neural pathway that involves impaired movement control to improve motor functions in people with spinal cord injuries. Since then, her research has focused on using this approach to help improve sensory and motor functions in people with spinal cord injuries to guide them toward restoration of these functions. In her own words, Dr. Thompson’s team is interested in “if and then how well we can guide the ability of the human nervous system to change its own neural pathways and their functions towards restoring useful sensory and motor functions in people after spinal cord damage and other nervous system disorders”.
In this episode, Dr. Thompson shares three examples of ongoing studies she is running – the first being operant down-conditioning of exaggerated spinal reflex in people with spasticity due to spinal cord damage. Based on the results of earlier studies that aim to tame this reflex using operant down-conditioning, the reflex became smaller, walking speed increased significantly, and participants noticed a decrease in spasticity in their daily lives.
The second approach uses non-invasive brain stimulation called transcranial magnetic stimulation to target changes in the brain to spinal cord pathway. Specifically, in those with foot drop, this method involves the application of operant up-conditioning to the dorsiflexor response to reduce foot drop and strengthen the brain-spinal cord pathway for the ankle muscles. Initial results have seen improved walking and lessened foot drop.
The third study addresses neuropathic pain after spinal cord injury. People with chronic spinal cord injury often have weakened reflexes to non-painful stimuli while also having exaggerated pain processing. To restore the balance between pain and non-pain processing, Dr. Thompson’s team is working on upregulating a non-painful skin sensation reflex to counter the heightened pain processing. Clinical trials are currently ongoing for this study with the potential to introduce non-invasive non-pharmaceutical means to reduce chronic neuropathic pain.
For those interested in participating, any person with spasticity, foot drop, arm and hand weakness, or neuropathic pain due to chronic spinal cord lesions is likely to be eligible to participate in at least one of these studies. Candidates must be generally healthy and not going through medication changes at the time of participation. Additionally, participants can continue ongoing therapies while they are in the study. If you are interested in potentially joining these studies, you can contact Dr. Thompson’s lab by email at [email protected] or by calling (843)792-6313. For more information on ongoing studies and publications, visit operantconditioning.org.
