@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 {3082,
	title = {Soleus H-reflex operant conditioning changes the H-reflex recruitment curve.},
	journal = {Muscle \& nerve},
	volume = {47},
	year = {2013},
	month = {04/2013},
	pages = {539{\textendash}544},
	abstract = {INTRODUCTION:
Operant conditioning can gradually change the human soleus H-reflex. The protocol conditions the reflex near M-wave threshold. In this study we examine its impact on the reflexes at other stimulus strengths.
METHODS:
H-reflex recruitment curves were obtained before and after a 24-session exposure to an up-conditioning (HRup) or a down-conditioning (HRdown) protocol and were compared.
RESULTS:
In both HRup and HRdown subjects, conditioning affected the entire H-reflex recruitment curve. In 5 of 6 HRup and 3 of 6 HRdown subjects, conditioning elevated (HRup) or depressed (HRdown), respectively, the entire curve. In the other HRup subject or the other 3 HRdown subjects, the curve was shifted to the left or to the right, respectively.
CONCLUSIONS:
H-reflex conditioning does not simply change the H-reflex to a stimulus of particular strength; it also changes the H-reflexes to stimuli of different strengths. Thus, it is likely to affect many actions in which this pathway participates.},
	keywords = {motor learning, plasticity, Rehabilitation, Spinal Cord},
	issn = {1097-4598},
	doi = {10.1002/mus.23620},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/23281107},
	author = {Thompson, Aiko K. and Xiang Yang Chen and Jonathan Wolpaw}
}
@article {3109,
	title = {Acquisition of a simple motor skill: task-dependent adaptation plus long-term change in the human soleus H-reflex.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {29},
	year = {2009},
	month = {05/2009},
	pages = {5784{\textendash}5792},
	abstract = {Activity-dependent plasticity occurs throughout the CNS. However, investigations of skill acquisition usually focus on cortex. To expand the focus, we analyzed in humans the development of operantly conditioned H-reflex change, a simple motor skill that develops gradually and involves plasticity in both the brain and the spinal cord. Each person completed 6 baseline and 24 conditioning sessions over 10 weeks. In each conditioning session, the soleus H-reflex was measured while the subject was or was not asked to increase (HRup subjects) or decrease (HRdown subjects) it. When the subject was asked to change H-reflex size, immediate visual feedback indicated whether a size criterion had been satisfied. Over the 24 conditioning sessions, H-reflex size gradually increased in six of eight HRup subjects and decreased in eight of nine HRdown subjects, resulting in final sizes of 140 +/- 12 and 69 +/- 6\% of baseline size, respectively. The final H-reflex change was the sum of within-session (i.e., task-dependent) adaptation and across-session (i.e., long-term) change. Task-dependent adaptation appeared within four to six sessions and persisted thereafter, averaging +13\% in HRup subjects and -15\% in HRdown subjects. In contrast, long-term change began after 10 sessions and increased gradually thereafter, reaching +27\% in HRup subjects and -16\% in HRdown subjects. Thus, the acquisition of H-reflex conditioning consists of two phenomena, task-dependent adaptation and long-term change, that together constitute the new motor skill. In combination with previous data, this new finding further elucidates the interaction of plasticity in brain and spinal cord that underlies the acquisition and maintenance of motor skills.},
	keywords = {H-Reflex, motor learning, motor skill, operant conditioning, plasticity, Spinal Cord},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.4326-08.2009},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19420246},
	author = {Thompson, Aiko K. and Xiang Yang Chen and Jonathan Wolpaw}
}
