PROLONGED CHANGES IN EXCITABILITY OF PYRAMIDAL TRACT NEURONS IN THE CAT - POST-SYNAPTIC MECHANISM

被引:43
作者
BINDMAN, LJ
LIPPOLD, OCJ
MILNE, AR
机构
来源
JOURNAL OF PHYSIOLOGY-LONDON | 1979年 / 286卷 / JAN期
关键词
D O I
10.1113/jphysiol.1979.sp012631
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
1. Prolonged changes in the excitability of cortical neurones can be produced by altering their firing rates for brief periods. In the anaesthetized cat, increased firing of pyramidal tract cells induced by trains of antidromic conditioning shocks led to increases in cell excitability, as measured by the size of the mass response at the medullary pyramid to test shocks applied to the cortical surface. We have shown in two ways that post‐synaptic mechanisms could be responsible. 2. In one experimental design, MgCl2 solution (1 mole/l.) was applied to the cortical surface in order to block synaptic activity throughout the cortical depth. Following antidromic conditioning trains, cell excitability was increased; the size of the mass response was up to 30% larger than the control values. This persisted undiminished for up to 3 hr. 3. In the second experimental design, synaptic activity was not blocked, but we compared the effects of antidromic plus synaptic activation of pyramidal tract cells with the effects of synaptic activation alone. Antidromic plus synaptic activation was obtained by applying conditioning trains to the pyramidal tract at the medulla ipsilateral to the cortical test shock; prolonged increases in the ipsilateral response to the test shock were produced. Synaptic activation alone was obtained by the same conditioning trains, but in those cells whose axons projected into the contralateral pyramidal tract; prolonged increases in the contralateral response to the cortical test shock were never seen. In many instances prolonged decreases in excitability were found. 4. We conclude that prolonged increases in excitability of pyramidal tract cells can occur in the absence of any synaptic input, demonstrating that the underlying mechanism is post‐synaptic; this does not preclude the action of synaptic mechanisms when synaptic transmission is not blocked. © 1979 The Physiological Society
引用
收藏
页码:457 / 477
页数:21
相关论文
共 28 条
[1]   Afferent discharges to the cerebral cortex from peripheral sense organs [J].
Adrian, ED .
JOURNAL OF PHYSIOLOGY-LONDON, 1941, 100 (02) :159-191
[2]  
ARMSTRONG DM, 1965, J PHYSIOL-LONDON, V178, pP37
[3]  
Bergmans J., 1970, PHYSL SINGLE HUMAN N
[4]  
BINDMAN LJ, 1977, J PHYSIOL-LONDON, V269, pP34
[5]  
BINDMAN LJ, 1976, J PHYSIOL-LONDON, V258, pP71
[6]  
BINDMAN LJ, 1976, J PHYSIOL-LONDON, V263, pP141
[7]   LONG-LASTING POTENTIATION OF SYNAPTIC TRANSMISSION IN DENTATE AREA OF ANESTHETIZED RABBIT FOLLOWING STIMULATION OF PERFORANT PATH [J].
BLISS, TVP ;
LOMO, T .
JOURNAL OF PHYSIOLOGY-LONDON, 1973, 232 (02) :331-356
[8]  
DIETESPIFF K, 1962, J PHYSIOL-LONDON, V162, pP44