02150nas a2200193   4500008004100000022001400041245007100055210006900126260001200195300001400207490000700221520158500228653001601813100002101829700002001850700001901870700002001889856004701909       1986                        eng d  a0022-307700aAdaptive plasticity in primate spinal stretch reflex: persistence.0 aAdaptive plasticity in primate spinal stretch reflex persistence  c02/1986  a272–2790 v553 aMonkeys can gradually change the amplitude of the wholly segmental, largely monosynaptic, spinal stretch reflex (SSR) when confronted by a task requiring such change (15-19). Change develops over months and may reverse and redevelop at similarly slow rates. We investigated the persistence of SSR amplitude change over nonperformance periods of up to 38 days. Eight animals with chronic EMG electrodes learned to maintain elbow angle and a given level of biceps background EMG against constant extension torque. At random times, a brief additional extension torque pulse elicited the biceps SSR. In the control mode, reward always followed. Under the SSR increase or SSR decrease mode, reward occurred only if the absolute value of biceps EMG in the SSR interval was above or below a set value. Animals completed 3,000-6,000 trials/day over data-collection periods of 2-17 mo. Animals worked first under the control mode for up to 60 days and then under the SSR increase or SSR decrease mode for up to 274 days. Mode was switched once or twice more (SSR increase to SSR decrease or vice versa) over subsequent months. Animals responded to each SSR increase or SSR decrease mode exposure with gradual mode-appropriate change in SSR amplitude. Mode exposures were interrupted by gaps in performance of 10-38 days. Gaps produced transient 10- to 15% decreases in SSR amplitude under the control mode. This nonspecific decrease disappeared over the first week of postgap performance. Under the control mode, gaps had no other effects on SSR amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)10aSpinal Cord1 aWolpaw, Jonathan1 aO'Keefe, J., A.1 aNoonan, P., A.1 aSanders, M., G.  uhttp://www.ncbi.nlm.nih.gov/pubmed/395069101147nas 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/399105701114nas 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/6860948