01147nas 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/6539634