02092nas a2200217   4500008004100000022001400041245009800055210006900153260001200222300001100234490000700245520143300252653001301685653001501698653002301713653002701736653002001763100002201783700002101805856004801826       2015                        eng d  a1089-409800aRestoring walking after spinal cord injury: operant conditioning of spinal reflexes can help.0 aRestoring walking after spinal cord injury operant conditioning   c04/2015  a203-150 v213 a<p>People with incomplete spinal cord injury (SCI) frequently suffer motor disabilities due to spasticity and poor muscle control, even after conventional therapy. Abnormal spinal reflex activity often contributes to these problems. Operant conditioning of spinal reflexes, which can target plasticity to specific reflex pathways, can enhance recovery. In rats in which a right lateral column lesion had weakened right stance and produced an asymmetrical gait, up-conditioning of the right soleus H-reflex, which increased muscle spindle afferent excitation of soleus, strengthened right stance and eliminated the asymmetry. In people with hyperreflexia due to incomplete SCI, down-conditioning of the soleus H-reflex improved walking speed and symmetry. Furthermore, modulation of electromyographic activity during walking improved bilaterally, indicating that a protocol that targets plasticity to a specific pathway can trigger widespread plasticity that improves recovery far beyond that attributable to the change in the targeted pathway. These improvements were apparent to people in their daily lives. They reported walking faster and farther, and noted less spasticity and better balance. Operant conditioning protocols could be developed to modify other spinal reflexes or corticospinal connections; and could be combined with other therapies to enhance recovery in people with SCI or other neuromuscular disorders.</p>10aLearning10aLocomotion10aspinal cord injury10aspinal cord plasticity10aspinal reflexes1 aThompson, Aiko, K1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/2463695402554nas a2200241   4500008004100000022001400041245016400055210006900219260001200288300001200300490000800312520178000320653001302100653001502113653001902128653001602147653001502163100002102178700002202199700002102221700002202242856004802264       2014                        eng d  a1522-159800aOperant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.0 aOperant conditioning of the soleus Hreflex does not induce longt  c09/2014  a1439-460 v1123 a<p>In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion.</p>10aLearning10aplasticity10aRehabilitation10aSpinal Cord10asynergists1 aMakihara, Yukiko1 aSegal, Richard, L1 aWolpaw, Jonathan1 aThompson, Aiko, K  uhttp://www.ncbi.nlm.nih.gov/pubmed/24944216