01573nas a2200229   4500008004100000022001400041245004600055210004100101260001200142300001400154490000700168520098800175653001301163653001301176653001101189653002501200653001501225653001601240653001901256100002101275856004701296       1997                        eng d  a0166-223600aThe complex structure of a simple memory.0 acomplex structure of a simple memory  c12/1997  a588–5940 v203 aOperant conditioning of the vertebrate H-reflex, which appears to be closely related to learning that occurs in real life, is accompanied by plasticity at multiple sites. Change occurs in the firing threshold and conduction velocity of the motoneuron, in several different synaptic terminal populations on the motoneuron, and probably in interneurons as well. Change also occurs contralaterally. The corticospinal tract probably has an essential role in producing this plasticity. While certain of these changes, such as that in the firing threshold, are likely to contribute to the rewarded behavior (primary plasticity), others might preserve previously learned behaviors (compensatory plasticity), or are simply activity-driven products of change elsewhere (reactive plasticity). As these data and those from other simple vertebrate and invertebrate models indicate, a complex pattern of plasticity appears to be the necessary and inevitable outcome of even the simplest learning.10aH-Reflex10aLearning10aMemory10aoperant conditioning10aplasticity10aSpinal Cord10astretch reflex1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/941667301398nas a2200241   4500008004100000022001400041245006300055210006100118260001200179300001400191490000700205520074600212653001700958653001300975653001100988653001500999653001201014653001801026653001901044100002101063700002501084856004701109       1990                        eng d  a0165-027000aOperant conditioning of H-reflex in freely moving monkeys.0 aOperant conditioning of Hreflex in freely moving monkeys  c02/1990  a145–1520 v313 aThe H-reflex, the electrical analog of the stretch reflex or tendon jerk, is the simplest behavior of the primate CNS. It is subserved by a wholly spinal two-neuron reflex arc. Recent studies show that this reflex can be increased or decreased by operant conditioning, and that such conditioning causes plastic changes in the spinal cord itself. Thus, H-reflex conditioning provides a powerful new model for investigating primate memory traces. The key feature of this model, the conditioning task, originally required animal restraint. This report describes a new tether-based design that allows H-reflex measurement and conditioning without restraint. This design integrates the conditioning task into the life of the freely moving animal.10aconditioning10aH-Reflex10aMemory10aplasticity10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan1 aHerchenroder, P., A.  uhttp://www.ncbi.nlm.nih.gov/pubmed/231981501345nas a2200229   4500008004100000022001400041245011800055210006900173260001200242300001400254490000700268520062900275653001900904653001200923653002500935653003500960653001800995653001901013100002101032700001501053856004701068       1988                        eng d  a0013-469400aSpinal stretch reflex and cortical evoked potential amplitudes versus muscle stretch amplitude in the monkey arm.0 aSpinal stretch reflex and cortical evoked potential amplitudes v  c04/1988  a394–3970 v693 aWhile investigating operant conditioning of the primate spinal stretch reflex (SSR), we studied SSR amplitude and cortical somatosensory evoked potential (SEP) amplitude as stretch amplitude changed in the monkey arm. Initial muscle length and background EMG activity remained constant. With change in stretch amplitude (and proportional change in stretch velocity and acceleration), changes in SSR and SEP amplitudes were respectively 0.75 and 0.66 as great. The lesser change in SSR amplitude may reflect saturation of Ia afferents, while that in SEP amplitude may also reflect participation of other peripheral receptors.10amuscle stretch10aprimate10aSomatosensory Cortex10asomatosensory evoked potential10aspinal reflex10astretch reflex1 aWolpaw, Jonathan1 aDowman, R.  uhttp://www.ncbi.nlm.nih.gov/pubmed/245073801802nas a2200217   4500008004100000022001400041245009300055210006900148260001200217300001400229490000700243520113900250653003101389653001401420653001601434653001901450653002701469100002301496700001801519856004701537       1986                        eng d  a0014-481900aEnhancement by serotonin of tonic vibration and stretch reflexes in the decerebrate cat.0 aEnhancement by serotonin of tonic vibration and stretch reflexes  c03/1986  a111–1220 v623 aThe effects of pharmacological manipulation of serotonergic systems on spinal reflexes were determined in the unanesthetized decerebrate cat. The prolonged motor output that continues after cessation of high frequency longitudinal tendon vibration was strongly enhanced by the serotonin reuptake blocker fluoxetine and the serotonin precursor 5-hydroxytryptophan, and was decreased by the serotonin receptor antagonist methysergide. In addition, both dynamic and static stretch reflex stiffness was markedly increased by fluoxetine and 5-hydroxytryptophan, while methysergide produced a decrease in stretch reflex stiffness. These powerful effects on tonic vibration and stretch reflexes could not be explained by drug-induced alterations in muscle spindle primary afferent discharge. In light of other recent results on serotonin-mediated effects on motoneurons, we believe that the effects of these agents result from modification of an intrinsically mediated prolonged depolarization of spinal neurons. However, the possibility that these drugs modify longlasting discharge in associated interneuronal pathways cannot be ruled out.10abistable neuronal behavior10aserotonin10aSpinal Cord10astretch reflex10atonic vibration reflex1 aCarp, Jonathan, S.1 aRymer, W., Z.  uhttp://www.ncbi.nlm.nih.gov/pubmed/300719101726nas a2200217   4500008004100000022001400041245009000055210006900145260001200214300001400226490000600240520110600246653001301352653001101365653001501376653001201391653001801403653001901421100002101440856004701461       1985                        eng d  a0272-434000aAdaptive plasticity in the spinal stretch reflex: an accessible substrate of memory?.0 aAdaptive plasticity in the spinal stretch reflex an accessible s  c06/1985  a147–1650 v53 aThe study of the substrates of memory in higher vertebrates is one of the major problems of neurobiology. A simple and technically accessible experimental model is needed. Recent studies have demonstrated long-term adaptive plasticity, a form of memory, in the spinal stretch reflex (SSR). The SSR is due largely to a two-neuron monosynaptic arc, the simplest, best-defined, and most accessible pathway in the primate central nervous system (CNS). Monkeys can slowly change SSR amplitude without a change in initial muscle length or alpha motoneuron tone, when reward is made contingent on amplitude. Change occurs over weeks and months and persists for long periods. It is relatively specific to the agonist muscle and affects movement. The salient features of SSR adaptive plasticity, combined with clinical and laboratory evidence indicating spinal cord capacity for intrinsic change, suggest that SSR change eventually involves persistent segmental alteration. If this is the case, SSR plasticity should be a powerful model for studying the neuronal and synaptic substrates of memory in a primate.10aLearning10aMemory10aplasticity10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/316161601147nas a2200253   4500008004100000022001400041245010300055210006900158260001200227300001400239490000700253520041700260653001300677653001100690653001500701653001200716653001800728653001900746100002100765700002000786700002000806700002000826856004700846       1985                        eng d  a0304-394000aReduced day-to-day variation accompanies adaptive plasticity in the primate spinal stretch reflex.0 aReduced daytoday variation accompanies adaptive plasticity in th  c03/1985  a165–1710 v543 aMonkeys can change the amplitude of the spinal stretch reflex (SSR), or M1, when reward is made contingent on amplitude. The present study demonstrates that reduced SSR day-to-day variation accompanies such adaptive SSR change. This finding supports the assumption that initial, phase I, SSR change results from contingency-appropriate stabilization of tonic activity in relevant descending spinal cord pathways.10aLearning10aMemory10aplasticity10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan1 aO'Keefe, J., A.1 aKieffer, V., A.1 aSanders, M., G.  uhttp://www.ncbi.nlm.nih.gov/pubmed/399105702097nas a2200241   4500008004100000022001400041245010700055210006900162260001200231300001400243490000800257520138500265653002401650653001901674653001301693653001101706653001201717653001901729100002101748700001901769700002001788856004701808       1984                        eng d  a0006-899300aAdaptive plasticity and diurnal rhythm in the primate spinal stretch reflex are independent phenomena.0 aAdaptive plasticity and diurnal rhythm in the primate spinal str  c05/1984  a385–3910 v3003 aRecent studies have revealed two phenomena producing considerable variation in amplitude of the initial, purely segmental, largely monosynaptic, response to sudden muscle stretch, the spinal stretch reflex (SSR), without change in background EMG activity or initial muscle length. The first is small and short-term, a modest diurnal rhythm in SSR amplitude. The second is large and long-term, marked adaptive change in SSR amplitude which occurs gradually over weeks and months when animals are rewarded for such change. This second phenomenon may involve persistent segmental alteration, and, if so, could constitute a technically accessible substrate of memory. The present study compared the two phenomena and sought evidence of interaction between them. The diurnal rhythm persisted, without change in phase and with only minimal change in amplitude, despite the occurrence of marked adaptive change. Animals did not utilize the rhythm to increase reward percentage by altering daily performance schedules. These results suggest that the mechanisms of the diurnal rhythm and of adaptive plasticity in SSR amplitude are separate and independent. The diurnal rhythm's effect on movement was not altered by adaptive change in SSR amplitude. This effect was comparable to adaptive change's effect on movement when both were expressed as change in movement/change in SSR amplitude.10aadaptive plasticity10adiurnal rhythm10aLearning10aMemory10aprimate10astretch reflex1 aWolpaw, Jonathan1 aNoonan, P., A.1 aO'Keefe, J., A.  uhttp://www.ncbi.nlm.nih.gov/pubmed/653963401504nas a2200217   4500008004100000022001400041245009100055210006900146260001200215300001400227490000800241520088100249653001301130653001101143653001501154653001201169653001801181653001901199100002101218856004701239       1983                        eng d  a0006-899300aAdaptive plasticity in the primate spinal stretch reflex: reversal and re-development.0 aAdaptive plasticity in the primate spinal stretch reflex reversa  c11/1983  a299–3040 v2783 aMonkeys can gradually increase or decrease the amplitude of the segmentally mediated spinal stretch reflex (SSR) without change in initial muscle length or background EMG activity. Both increase (under the SSR increases mode) and decrease (under the SSR decreases mode) occur slowly, progressing steadily over weeks. The present study investigated reversal and re-development of SSR amplitude change. Over a period of months, following collection of control data, monkeys were exposed to one mode, then to the other, and then to the first mode again. Development, reversal, and re-development of change all took place over weeks, following very similar courses. These data are consistent with the hypothesis that persistent segmental alteration underlies SSR amplitude change. Such persistent segmental alteration would constitute a technically accessible substrate of memory.10aLearning10aMemory10aplasticity10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan  uhttp://www.ncbi.nlm.nih.gov/pubmed/664032001114nas a2200265   4500008004100000022001400041245005400055210005300109260001200162300001400174490000800188520041600196653001300612653001100625653001500636653001200651653001800663653001900681100002100700700002000721700001900741700002100760700002000781856004700801       1983                        eng d  a0006-899300aAdaptive plasticity in the spinal stretch reflex.0 aAdaptive plasticity in the spinal stretch reflex  c05/1983  a196–2000 v2673 aMonkeys can change the amplitude of the spinal stretch reflex without change in initial alpha motor neuron tone, as measured by EMG, or in initial muscle length. Change is apparent in 5-10 days, continues to develop over weeks, and persists during inactive periods. Spinal stretch reflex change may be a valuable system for studying the neuronal and synaptic bases of an adaptive change in primate CNS function.10aLearning10aMemory10aplasticity10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan1 aKieffer, V., A.1 aSeegal, R., F.1 aBraitman, D., J.1 aSanders, M., G.  uhttp://www.ncbi.nlm.nih.gov/pubmed/686094801145nas a2200229   4500008004100000022001400041245004900055210004800104260001200152300001400164490000800178520053400186653002100720653001900741653001900760653001200779653001800791653001900809100002100828700001900849856004700868       1982                        eng d  a0006-899300aDiurnal rhythm in the spinal stretch reflex.0 aDiurnal rhythm in the spinal stretch reflex  c07/1982  a365–3690 v2443 aWe studied primate spinal stretch reflex (SSR) amplitude as a function of time of day. SSR amplitude was greatest around midnight and smallest around noon. The diurnal rhythm was not simply a function of number of trials, or of the lighting cycle. This rhythm offers an opportunity to study the neuronal and synaptic mechanisms producing a diurnal change in CNS function. Its existence indicates that the CNS response to a given limb disturbance, and thus the CNS activity underlying a given performance, varies with time of day.10acircadian rhythm10adiurnal rhythm10amuscle stretch10aprimate10aspinal reflex10astretch reflex1 aWolpaw, Jonathan1 aSeegal, R., F.  uhttp://www.ncbi.nlm.nih.gov/pubmed/6889452