01903nas a2200301   4500008004100000022001400041245010700055210006900162260001200231300001800243490000700261520101900268653002601287653001301313653001501326653001101341653001801352653001901370653002301389653002701412100001301439700002101452700002101473700001301494700002501507700002101532856004801553       2006                        eng d  a1529-240100aOperant conditioning of H-reflex can correct a locomotor abnormality after spinal cord injury in rats.0 aOperant conditioning of Hreflex can correct a locomotor abnormal  c11/2006  a12537–125430 v263 a<p>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.</p>10aH-reflex conditioning10aLearning10aLocomotion10aMemory10aMotor control10aRehabilitation10aspinal cord injury10aspinal cord plasticity1 aChen, Yi1 aChen, Xiang Yang1 aJakeman, Lyn, B.1 aChen, Lu1 aStokes, Bradford, T.1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/1713541501877nas a2200253   4500008004100000022001400041245007900055210006900134260001200203300001400215490000800229520115300237653002201390653002401412653001901436653001301455653000801468653002301476100002101499700001301520700002101533700002101554856004801575       2002                        eng d  a0006-899300aCorticospinal tract transection reduces H-reflex circadian rhythm in rats.0 aCorticospinal tract transection reduces Hreflex circadian rhythm  c06/2002  a101–1080 v9423 aIn freely moving rats and monkeys, H-reflex amplitude displays a marked circadian variation without change in background motoneuron tone. In rats, the H-reflex is largest around noon and smallest around midnight. The present study evaluated in rats the effects on this rhythm of calibrated contusions of mid-thoracic spinal cord and mid-thoracic transection of specific spinal cord pathways. In 33 control rats, rhythm amplitude averaged 29.0(+/-2.6 S.E.)% of H-reflex amplitude. Contusion injuries at T8-9 that destroyed 53-88% of the white matter significantly reduced the rhythm to 18.9(+/-2.4)% of H-reflex amplitude. Transection of the ipsilateral lateral column, which contains the rubrospinal, vestibulospinal, and reticulospinal tracts, or bilateral transection of the dorsal column ascending tract did not affect rhythm amplitude or phase. In contrast, bilateral transection of the main corticospinal tract significantly reduced the rhythm to 14.7(+/-6.6)%. These results indicate that the H-reflex circadian rhythm depends in part on descending influence from the brain and that this influence is conveyed by the main corticospinal tract.10acircadian rhythms10acorticospinal tract10adiurnal rhythm10aH-Reflex10arat10aspinal cord injury1 aChen, Xiang Yang1 aChen, Lu1 aWolpaw, Jonathan1 aJakeman, Lyn, B.  uhttp://www.ncbi.nlm.nih.gov/pubmed/12031858