Cortical Plasticity After SCI
Recent work has shown that the central nervous system is capable of plastic behaviors post-injury, including axonal regrowth and cortical remapping. Functional integrity of afferent sensory pathways can be quantified using cortical somatosensory evoked potentials (SEPs) recorded upon peripheral limb stimulation.
We are able to monitor the changes in cortical function that occur over the weeks following a spinal cord injury. We measure these plastic responses in the brain using our advanced SEP monitoring setup. Our results have shown that after an SCI that injures hindlimb pathways, the previously allocated hindlimb cortical regions become activated by forelimb stimulation. This suggests an expansion in the area of cortical forelimb representation into hindlimb regions after an injury. This result is indicative of adaptive plasticity in undamaged areas of the central nervous system following SCI.
We are also able to monitor plasticity using functional magnetic resonance imaging (fMRI). Other groups have also reported an increase in cortical fMRI responses in the forelimb somatosensory cortex due to forepaw stimulation after a spinal cord hemisection; and that the area of activation in the cortex expands into the previously mapped hindlimb area that suggests rewiring mechanisms (3). The image below is one wer acquired that illustrates this phenomenon.
- This work has been published in: Faith A. Bazley, Angelo H. All, Nitish V. Thakor, Candace Kerr, Anil Maybhate. "Plasticity Associated Changes in Cortical Somatosensory Evoked Potentials following Spinal Cord Injury in Rats". Accepted Jun 2011 to IEEE EBMS Conference Proceedings.
- Special thanks to those who helped with the image acquisition: Galit Pelled, Yang Han, Nan Li, and Anil Maybhate
- A. Ghosh, et al., "Rewiring of hindlimb corticospinal neurons after spinal cord injury," Nature Neuroscience, vol. 13, pp. 97-104, 2009