@article {3080,
	title = {Operant conditioning of a spinal reflex can improve locomotion after spinal cord injury in humans.},
	journal = {The Journal of neuroscience : the official journal of the Society for Neuroscience},
	volume = {33},
	year = {2013},
	month = {02/2013},
	pages = {2365{\textendash}2375},
	abstract = {Operant conditioning protocols can modify the activity of specific spinal cord pathways and can thereby affect behaviors that use these pathways. To explore the therapeutic application of these protocols, we studied the impact of down-conditioning the soleus H-reflex in people with impaired locomotion caused by chronic incomplete spinal cord injury. After a baseline period in which soleus H-reflex size was measured and locomotion was assessed, subjects completed either 30 H-reflex down-conditioning sessions (DC subjects) or 30 sessions in which the H-reflex was simply measured [unconditioned (UC) subjects], and locomotion was reassessed. Over the 30 sessions, the soleus H-reflex decreased in two-thirds of the DC subjects (a success rate similar to that in normal subjects) and remained smaller several months later. In these subjects, locomotion became faster and more symmetrical, and the modulation of EMG activity across the step cycle increased bilaterally. Furthermore, beginning about halfway through the conditioning sessions, all of these subjects commented spontaneously that they were walking faster and farther in their daily lives, and several noted less clonus, easier stepping, and/or other improvements. The H-reflex did not decrease in the other DC subjects or in any of the UC subjects; and their locomotion did not improve. These results suggest that reflex-conditioning protocols can enhance recovery of function after incomplete spinal cord injuries and possibly in other disorders as well. Because they are able to target specific spinal pathways, these protocols could be designed to address each individual{\textquoteright}s particular deficits, and might thereby complement other rehabilitation methods.},
	keywords = {Learning, Locomotion, operant conditioning, plasticity, Rehabilitation, spasticity},
	issn = {1529-2401},
	doi = {10.1523/JNEUROSCI.3968-12.2013},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/23392666},
	author = {Thompson, Aiko K. and Pomerantz, Ferne R. 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}
}
