Detecting neuroplasticity after spinal cord injury: Implications for neuropathic pain

Current interventions for neuropathic pain after spinal cord injury (SCI) have proven largely ineffective, an unfavorable outcome that can be partly attributed to poor understanding of mechanisms.

Through his research program, Dr. Kramer aims to shed light on this problem, focusing specifically on the hypothesis that changes in supraspinal (above the spine) structures contribute to neuropathic pain symptoms (e.g., burning sensation in the legs). In experiments using functional magnetic resonance imaging (MRI) and electroencephalography, a technique for measuring electrical activity in the brain, the brain activities following afferent stimulation in individuals with SCI will be investigated.

In an initial experiment, Dr. Kramer will explore how descending control of nociception, the neural processes of encoding and processing noxious stimuli, is affected by SCI. This will be done using behavioral manipulations to control awareness to noxious stimuli (e.g. placebo-analgesia, the inability to feel pain).

In the second experiment, Dr. Kramer will build on preliminary results, which indicate that neuropathic pain is associated with prominent changes in cortical functioning in brain areas involved in processing noxious stimuli. Beyond cortical functioning, he will also examine the role of plasticity in the brainstem in the maintenance of neuropathic pain.

In a final experiment, Dr. Kramer will delve further into the role of cortical and brainstem plasticity, determining the time course for when these changes occur. In proposed imaging experiments, the extent by which structural changes in the central nervous system accompany sensory deficits will be examined using quantitative anatomical MRI techniques.

As part of Dr. Kramer’s ongoing research program, quantitative approaches to objectively assess sensory function will continue to be developed. The focus of this work will be on validating novel neurophysiological and neuroimaging techniques to examine discrete elements of sensory impairments. Additionally, Dr. Kramer will continue to investigate the inter-relationship between neuropathic pain, other secondary complications (e.g., cardiovascular disease), and neurological recovery by analyzing large epidemiological SCI databases.

Overall, the research program will provide a clearer picture of the impact of neuropathic pain on neurological function, methods to improve objective measurement, and will enable implementation of novel interventions aimed at improving outcomes and quality of life for people with SCI.