Observations on interaction of nerve impulses in the gray matter and on the nature of central inhibition.
Observations on interaction of nerve impulses in the gray matter and on the nature of central inhibition.
复制标题
观察灰质中神经冲动的相互作用和中枢抑制的性质。
DOI：
10.1152/ajplegacy.1946.146.3.443
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发表时间：
1946
期刊：
影响因子：
--
通讯作者：
B. Renshaw
中科院分区：
文献类型：
--
作者：
B. Renshaw
Background. It will be recalled that, in cats lightly anesthetized with pentobarbital sodium, a volley of impulses entering the spinal cord over fibers of the sixth lumbar dorsal root (LBDR) evokes discharges of motoneurons whose axons pass peripherally in the crural nerve to innervate the quadriceps muscle (Renshaw, 1942b). The central reflex time is 0.9-1.6 msec. Undoubtedly the shorter times in this range, and probably the longer ones as well, include but a single synaptic delay. The reflex discharge is inhibited by an antecedent LYDR volley, which in isolation initiates impulses in none of the quadriceps motoneurons. The inhibition is first apparent if the LTDR impulses arrive at the cord 1.0-1.1 msec. before the motoneurons discharge, ie, if the LTDR and the LGDR volleys arrive at the cord virtually simultaneously. As the interval at which the L7DR volley precedes the LGDR volley increases, the inhibition rapidly increases and becomes complete; it subsequently declines to disappear when the interval becomes 200 or more msec. It will also be recalled that antidromic impulses in motor axons invade the somas (cell bodies plus dendrites) of the corresponding motoneurons, producing action potentials (Lorente de No, 1939), and that one measure of the responsiveness of the motoneurons in a motor nucleus is the size of the antidromically-evoked somatic action potential as recorded by means of an appropriately placed micro-electrode (Renshaw, 1942a). Measured in this way, the changes induced in the quadriceps motoneurons subsequent to LeDR and LrDR volleys are qualitatively similar to those measured by the size of reflex discharges evoked in the quadriceps branches of the crural nerve by a testing LGDR volley, ie, an LGDR volley produces a brief period of facilitation followed
