%0 Journal Article %J The Journal of neuroscience : the official journal of the Society for Neuroscience %D 2006 %T Operant conditioning of H-reflex can correct a locomotor abnormality after spinal cord injury in rats. %A Yi Chen %A Xiang Yang Chen %A Jakeman, Lyn B. %A Lu Chen %A Stokes, Bradford T. %A Jonathan Wolpaw %K H-reflex conditioning %K Learning %K Locomotion %K Memory %K Motor control %K Rehabilitation %K spinal cord injury %K spinal cord plasticity %X

This study asked whether operant conditioning of the H-reflex can modify locomotion in spinal cord-injured rats. Midthoracic transection of the right lateral column of the spinal cord produced a persistent asymmetry in the muscle activity underlying treadmill locomotion. The rats were then either exposed or not exposed to an H-reflex up-conditioning protocol that greatly increased right soleus motoneuron response to primary afferent input, and locomotion was reevaluated. H-reflex up-conditioning increased the right soleus burst and corrected the locomotor asymmetry. In contrast, the locomotor asymmetry persisted in the control rats. These results suggest that appropriately selected reflex conditioning protocols might improve function in people with partial spinal cord injuries. Such protocols might be especially useful when significant regeneration becomes possible and precise methods for reeducating the regenerated spinal cord neurons and synapses are needed for restoring effective function.

%B The Journal of neuroscience : the official journal of the Society for Neuroscience %V 26 %P 12537–12543 %8 11/2006 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/17135415 %R 10.1523/JNEUROSCI.2198-06.2006 %0 Journal Article %J The Journal of neuroscience : the official journal of the Society for Neuroscience %D 2005 %T The interaction of a new motor skill and an old one: H-reflex conditioning and locomotion in rats. %A Yi Chen %A Xiang Yang Chen %A Jakeman, Lyn B. %A Gerwin Schalk %A Stokes, Bradford T. %A Jonathan Wolpaw %K H-reflex conditioning %K Learning %K Locomotion %K memory consolidation %K Motor control %K Rehabilitation %K spinal cord plasticity %X New and old motor skills can interfere with each other or interact in other ways. Because each skill entails a distributed pattern of activity-dependent plasticity, investigation of their interactions is facilitated by simple models. In a well characterized model of simple learning, rats and monkeys gradually change the size of the H-reflex, the electrical analog of the spinal stretch reflex. This study evaluates in normal rats the interactions of this new skill of H-reflex conditioning with the old well established skill of overground locomotion. In rats in which the soleus H-reflex elicited in the conditioning protocol (i.e., the conditioning H-reflex) had been decreased by down-conditioning, the H-reflexes elicited during the stance and swing phases of locomotion (i.e., the locomotor H-reflexes) were also smaller. Similarly, in rats in which the conditioning H-reflex had been increased by up-conditioning, the locomotor H-reflexes were also larger. Soleus H-reflex conditioning did not affect the duration, length, or right/left symmetry of the step cycle. However, the conditioned change in the stance H-reflex was positively correlated with change in the amplitude of the soleus locomotor burst, and the correlation was consistent with current estimates of the contribution of primary afferent input to the burst. Although H-reflex conditioning and locomotion did not interfere with each other, H-reflex conditioning did affect how locomotion was produced: it changed soleus burst amplitude and may have induced compensatory changes in the activity of other muscles. These results illustrate and clarify the subtlety and complexity of skill interactions. They also suggest that H-reflex conditioning might be used to improve the abnormal locomotion produced by spinal cord injury or other disorders of supraspinal control. %B The Journal of neuroscience : the official journal of the Society for Neuroscience %V 25 %P 6898–6906 %8 07/2005 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/16033899 %R 10.1523/JNEUROSCI.1684-05.2005