01079nas a2200181   4500008004100000022001400041245005300055210005200108260001200160300001400172490000800186520058000194653001600774100002100790700001600811700002300827856004700850       1991                        eng d  a0077-892300aOperantly conditioned plasticity in spinal cord.0 aOperantly conditioned plasticity in spinal cord  c08/1991  a338–3480 v6273 aRecent work has shown that the monosynaptic pathway of the SSR can be operantly conditioned, and that a significant part of the plasticity responsible for the behavioral change resides in the spinal cord. The most likely sites of this activity-driven plasticity are the synapse of the Ia afferent neuron on the motoneuron and/or the motoneuron itself. Because the SSR pathway is the simplest and most accessible stimulus-response pathway in the vertebrate CNS, it may provide a valuable experimental model for elucidating activity-driven CNS changes responsible for learning.10aSpinal Cord1 aWolpaw, Jonathan1 aLee, C., L.1 aCarp, Jonathan, S.  uhttp://www.ncbi.nlm.nih.gov/pubmed/188314303194nas a2200169   4500008004100000022001400041245008700055210006900142260001200211300001400223490000700237520268000244653001602924100002102940700001602961856004702977       1989                        eng d  a0022-307700aMemory traces in primate spinal cord produced by operant conditioning of H-reflex.0 aMemory traces in primate spinal cord produced by operant conditi  c03/1989  a563–5720 v613 a1. Study of memory traces in higher animals requires experimental models possessing well-localized and technically accessible memory traces–plasticity responsible for behavioral change, not dependent on control from elsewhere, and open to detailed investigation. Our purpose has been to develop such a model based on the wholly spinal, largely monosynaptic path of the spinal stretch reflex. Previous studies described operant conditioning of this reflex and of its electrical analog, the H-reflex. In this study, we sought to determine whether conditioning causes changes in the spinal cord that affect the reflex and are not dependent on continued supraspinal influence, and thus qualify as memory traces. 2. Sixteen monkeys underwent chronic conditioning of the triceps surae H-reflex. Eight were rewarded for increasing H-reflex amplitude (HR increases mode), and eight were rewarded for decreasing it (HR decreases mode). In each animal, the other leg was an internal control. Over several months of conditioning, H-reflex amplitude in the conditioned leg rose in HR increases animals and fell in HR decreases animals. H-reflex amplitude in the control leg changed little. 3. After HR increases or HR decreases conditioning, each animal was deeply anesthetized and surgically prepared. The reflex response to supramaximal dorsal root stimulation was measured from the triceps surae nerve as percent of response to supramaximal ventral root stimulation, which was the maximum possible response. Data from both legs were collected before and for up to 3 days after thoracic (T9-10) cord transection. The animal remained deeply anesthetized throughout and was killed by overdose. 4. The reflex asymmetries produced by conditioning were still present several days after transection removed supraspinal influence: reflexes of HR increases animals were significantly larger in HR increases legs than in control legs and reflexes of HR decreases animals were significantly smaller in HR decreases legs than in control legs. 5. Reflex amplitude was much greater in the control legs of anesthetized HR decreases animals than in the control legs of anesthetized HR increases animals. 6. Chronic conditioning had at least two effects on the spinal cord. The first effect, task-appropriate reflex asymmetry, was evident both in the awake behaving animal and in the anesthetized transected animal. The second effect, larger control leg reflexes in HR decreases than in HR increases animals, was evident only in the anesthetized animal. By removing supraspinal control, anesthesia and transection revealed a previously hidden effect of conditioning.(ABSTRACT TRUNCATED AT 400 WORDS)10aSpinal Cord1 aWolpaw, Jonathan1 aLee, C., L.  uhttp://www.ncbi.nlm.nih.gov/pubmed/270910001794nas a2200253   4500008004100000022001400041245008600055210006900141260001200210300001200222490000700234520107100241653001301312653001101325653002401336653002501360653001501385653001601400653001801416100002101434700001601455700002201471856004701493       1989                        eng d  a0014-481900aOperant conditioning of primate triceps surae H-reflex produces reflex asymmetry.0 aOperant conditioning of primate triceps surae Hreflex produces r  c03/1989  a35–390 v753 aMonkeys are able to increase or decrease triceps surae H-reflex when reward depends on reflex amplitude. Operantly conditioned change occurs over weeks and produces persistent alterations in the lumbosacral spinal cord which should be technically accessible substrates of primate memory. Previous work monitored and conditioned triceps surae H-reflex in one leg. To determine whether H-reflex conditioning in one leg affects the control leg, the present study monitored H-reflexes in both legs while the reflex in one leg underwent HR increases or HR decreases conditioning. Under the HR increases mode, H-reflex increase was much greater in the HR increases leg than in the control leg. Under the HR decreases mode, H-reflex decrease was confined to the HR decreases leg. By showing that conditioning of one leg's H-reflex produces H-reflex asymmetry, the data further define the phenomenon and indicate that the other leg can serve as an internal control for physiologic and anatomic studies exploring the sites and mechanisms of the spinal cord memory substrates.10aLearning10aMemory10amonosynaptic reflex10aoperant conditioning10aplasticity10aSpinal Cord10aspinal reflex1 aWolpaw, Jonathan1 aLee, C., L.1 aCalaitges, J., G.  uhttp://www.ncbi.nlm.nih.gov/pubmed/270735401361nas a2200229   4500008004100000022001400041245010600055210006900161260001200230300001400242490000700256520067400263653002400937653001200961653001600973653002300989653001801012653001701030100002101047700001601068856004701084       1987                        eng d  a0014-481900aMotoneuron response to dorsal root stimulation in anesthetized monkeys after spinal cord transection.0 aMotoneuron response to dorsal root stimulation in anesthetized m  c10/1987  a428–4330 v683 aIn preparation for studying the spinal cord alterations produced by operant conditioning of spinal reflexes, we studied peripheral nerve responses to supramaximal dorsal root stimulation in the lumbosacral cord of deeply anesthetized monkeys before and after thoracic cord transection. Except for variable depression in the first few minutes, reflex responses were not reduced or otherwise significantly affected by transection in the hour immediately following the lesion or for at least 50 h. The results suggest that reduction in muscle spindle sensitivity and/or in polysynaptic motoneuron excitation contributes to stretch reflex depression after cord transection.10amonosynaptic reflex10aprimate10aSpinal Cord10aspinal cord injury10aspinal reflex10aspinal shock1 aWolpaw, Jonathan1 aLee, C., L.  uhttp://www.ncbi.nlm.nih.gov/pubmed/3480233