ACTIONS ON GAMMA-MOTONEURONES ELICITED BY ELECTRICAL-STIMULATION OF GROUP-I MUSCLE AFFERENT-FIBERS IN THE HINDLIMB OF THE CAT
ACTIONS ON GAMMA-MOTONEURONES ELICITED BY ELECTRICAL-STIMULATION OF GROUP-I MUSCLE AFFERENT-FIBERS IN THE HINDLIMB OF THE CAT
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DOI：
10.1113/jphysiol.1983.sp014531
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发表时间：
1983-01-01
影响因子：
5.5
通讯作者：
SOJKA, P
中科院分区：
文献类型：
--
作者：
APPELBERG, B;HULLIGER, M;SOJKA, P
The reflex actions elicited by graded electrical stimulation of hindlimb muscle, skin and joint nerves were studied in an extended series of experiments in extra- and intracellular recordings from 120 lumbar .gamma.-motoneurons of cats anesthetized with chloralose. The action of group I muscle afferent fibers was examined in 95 .gamma.-cells. Of the .gamma.-cells, 83% were classified as either static or dynamic by stimulation in the mesencephalic area for dynamic control. The general responsiveness (i.e., number of input nerves with effect/number of input nerves tested) of the cells was very high (89.9%). The responsiveness to stimulation of group I muscle afferent fibers was extremely low, both in flexor and extensor .gamma.-motoneurons, irrespective of whether they were static or dynamic. There was no difference, as regards the low incidence of group I muscle reflex action, between stimulation of autogenetic and heteronymous nerves. Among the rare reflex effects elicited from group I muscle fibers, inhibition was 4 times as frequent as excitation. Inhibitory effects could be provoked from the autogenetic as well as from the heteronymous nerves. Excitatory effects were almost always autogenetic. The scarcity of group I muscle action on .gamma.-motoneurons is in striking contrast to the well-known and powerful reflex actions of Ia and Ib fibers on .alpha.-motoneurons. These findings are discussed in relation to the concept of .alpha.-.gamma. linkages, and skeletomotor and fusimotor activity cannot be rigidly linked under all conditions.
