@article {4094,
	title = {Why New Spinal Cord Plasticity Does Not Disrupt Old Motor Behaviors},
	journal = {The Journal of Neuroscience},
	volume = {37},
	year = {2017},
	month = {July},
	pages = {8198-8206},
	abstract = {When new motor learning changes the spinal cord, old behaviors are not impaired; their key features are preserved by additional compensatory plasticity. To explore the mechanisms responsible for this compensatory plasticity, we transected the spinal dorsal ascending tract before or after female rats acquired a new behavior{\textemdash}operantly conditioned increase or decrease in the right soleus H-reflex{\textemdash}and examined an old behavior{\textemdash}locomotion. Neither spinal dorsal ascending tract transection nor H-reflex conditioning alone impaired locomotion. Nevertheless, when spinal dorsal ascending tract transection and H-reflex conditioning were combined, the rats developed a limp and a tilted posture that correlated in direction and magnitude with the H-reflex change. When the right H-reflex was increased by conditioning, the right step lasted longer than the left and the right hip was higher than the left; when the right H-reflex was decreased by conditioning, the opposite occurred. These results indicate that ascending sensory input guides the compensatory plasticity that normally prevents the plasticity underlying H-reflex change from impairing locomotion. They support the concept of the state of the spinal cord as a negotiated equilibrium that reflects the concurrent influences of all the behaviors in an individual{\textquoteright}s repertoire; and they support the new therapeutic strategies this concept introduces.},
	keywords = {H-Reflex, motor learning, operant conditioning, plasticity, Rehabilitation, Spinal Cord},
	doi = {10.1523/JNEUROSCI.0767-17.2017},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5566867/},
	author = {Chen, Yi and Chen, Lu and Wang, Yu and Chen, Xiang Yang and Jonathan Wolpaw}
}
@article {3390,
	title = {Locomotor impact of beneficial or nonbeneficial H-reflex conditioning after spinal cord injury.},
	journal = {J Neurophysiol},
	volume = {111},
	year = {2014},
	month = {03/2014},
	pages = {1249-58},
	abstract = {When new motor learning changes neurons and synapses in the spinal cord, it may affect previously learned behaviors that depend on the same spinal neurons and synapses. To explore these effects, we used operant conditioning to strengthen or weaken the right soleus H-reflex pathway in rats in which a right spinal cord contusion had impaired locomotion. When up-conditioning increased the H-reflex, locomotion improved. Steps became longer, and step-cycle asymmetry (i.e., limping) disappeared. In contrast, when down-conditioning decreased the H-reflex, locomotion did not worsen. Steps did not become shorter, and asymmetry did not increase. Electromyographic and kinematic analyses explained how H-reflex increase improved locomotion and why H-reflex decrease did not further impair it. Although the impact of up-conditioning or down-conditioning on the H-reflex pathway was still present during locomotion, only up-conditioning affected the soleus locomotor burst. Additionally, compensatory plasticity apparently prevented the weaker H-reflex pathway caused by down-conditioning from weakening the locomotor burst and further impairing locomotion. The results support the hypothesis that the state of the spinal cord is a "negotiated equilibrium" that serves all the behaviors that depend on it. When new learning changes the spinal cord, old behaviors undergo concurrent relearning that preserves or improves their key features. Thus, if an old behavior has been impaired by trauma or disease, spinal reflex conditioning, by changing a specific pathway and triggering a new negotiation, may enable recovery beyond that achieved simply by practicing the old behavior. Spinal reflex conditioning protocols might complement other neurorehabilitation methods and enhance recovery.},
	keywords = {Animals, Conditioning, Operant, Female, H-Reflex, Learning, Locomotion, Male, Rats, Rats, Sprague-Dawley, Spinal Cord Injuries},
	issn = {1522-1598},
	doi = {10.1152/jn.00756.2013},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/24371288},
	author = {Yi Chen and Lu Chen and Liu, Rongliang and Wang, Yu and Xiang Yang Chen and Jonathan Wolpaw}
}
@article {3100,
	title = {Reflex conditioning: a new strategy for improving motor function after spinal cord injury.},
	journal = {Annals of the New York Academy of Sciences},
	volume = {1198 Suppl 1},
	year = {2010},
	month = {06/2010},
	pages = {E12{\textendash}E21},
	abstract = {Spinal reflex conditioning changes reflex size, induces spinal cord plasticity, and modifies locomotion. Appropriate reflex conditioning can improve walking in rats after spinal cord injury (SCI). Reflex conditioning offers a new therapeutic strategy for restoring function in people with SCI. This approach can address the specific deficits of individuals with SCI by targeting specific reflex pathways for increased or decreased responsiveness. In addition, once clinically significant regeneration can be achieved, reflex conditioning could provide a means of reeducating the newly (and probably imperfectly) reconnected spinal cord.},
	keywords = {H-Reflex, learning and memory, Locomotion, plasticity, reflex conditioning, Rehabilitation, spinal cord injury},
	issn = {1749-6632},
	doi = {10.1111/j.1749-6632.2010.05565.x},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/20590534},
	author = {Xiang Yang Chen and Yi Chen and Wang, Yu and Thompson, Aiko and Jonathan S. Carp and Segal, Richard L. and Jonathan Wolpaw}
}
@article {3193,
	title = {Motor learning changes GABAergic terminals on spinal motoneurons in normal rats.},
	journal = {The European journal of neuroscience},
	volume = {23},
	year = {2006},
	month = {01/2006},
	pages = {141{\textendash}150},
	abstract = {The role of spinal cord plasticity in motor learning is largely unknown. This study explored the effects of H-reflex operant conditioning, a simple model of motor learning, on GABAergic input to spinal motoneurons in rats. Soleus motoneurons were labeled by retrograde transport of a fluorescent tracer and GABAergic terminals on them were identified by glutamic acid decarboxylase (GAD)67 immunoreactivity. Three groups were studied: (i) rats in which down-conditioning had reduced the H-reflex (successful HRdown rats); (ii) rats in which down-conditioning had not reduced the H-reflex (unsuccessful HRdown rats) and (iii) unconditioned (naive) rats. The number, size and GAD density of GABAergic terminals, and their coverage of the motoneuron, were significantly greater in successful HRdown rats than in unsuccessful HRdown or naive rats. It is likely that these differences are due to modifications in terminals from spinal interneurons in lamina VI-VII and that the increased terminal number, size, GAD density and coverage in successful HRdown rats reflect and convey a corticospinal tract influence that changes motoneuron firing threshold and thereby decreases the H-reflex. GABAergic terminals in spinal cord change after spinal cord transection. The present results demonstrate that such spinal cord plasticity also occurs in intact rats in the course of motor learning and suggest that this plasticity contributes to skill acquisition.},
	keywords = {activity-dependent plasticity, GABA, H-Reflex, Memory, Motor control, Spinal Cord},
	issn = {0953-816X},
	doi = {10.1111/j.1460-9568.2005.04547.x},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16420424},
	author = {Wang, Yu and Pillai, Shreejith and Jonathan Wolpaw and Xiang Yang Chen}
}
