01682nas a2200181   4500008004100000022001400041245010400055210006900159260001200228300001600240490000700256520111400263653001601377100002101393700001901414700002001433856004701453       1983                        eng d  a0022-307700aAdaptive plasticity in primate spinal stretch reflex: behavior of synergist and antagonist muscles.0 aAdaptive plasticity in primate spinal stretch reflex behavior of  c12/1983  a1312–13190 v503 aMonkeys can gradually change the amplitude of the biceps spinal stretch reflex (SSR) without change in initial muscle length or biceps background electromyographic activity (EMG) (17). We investigated the concurrent behavior of synergist (brachialis and brachioradialis) and antagonist (triceps) muscles. Synergist background EMG remained stable while marked change occurred in biceps SSR amplitude. Triceps background EMG was minimal under all conditions. Thus biceps SSR amplitude change was not due to change in the background activity of closely related muscles. When biceps SSR amplitude changed, synergist SSR amplitude changed similarly but to a lesser extent. Brachialis change averaged 72% of biceps change, while brachioradialis change averaged 33%. By indicating that SSR amplitude change is relatively specific to the agonist muscle, this finding eliminates a number of nonspecific mechanisms as possible origins of SSR amplitude change. Thus it supports the potential value of the SSR as a system for studying the neuronal and synaptic bases of memory in the primate central nervous system (CNS).10aSpinal Cord1 aWolpaw, Jonathan1 aSeegal, R., F.1 aO'Keefe, J., A.  uhttp://www.ncbi.nlm.nih.gov/pubmed/6663328