Horizontal long-term potentiation of responses in rat somatosensory cortex.
Horizontal long-term potentiation of responses in rat somatosensory cortex.
复制标题
大鼠体感皮层反应的水平长期增强。
DOI：
10.1016/0006-8993(91)90069-8
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发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Ebner,FF
中科院分区：
文献类型：
--
作者：
Lee,SM;Weisskopf,MG;Ebner,FF
在新皮层中，通过活动依赖过程改变突触效能和产生联想学习的机制的研究主要集中在n -甲基-d-天冬氨酸（NMDA）型谷氨酸受体的作用。NMDA受体的激活对于海马12和新皮层2的长期增强（LTP）的诱导是必要的。NMDA受体激活的影响通过几种方式调节，包括Mg2+阻断NMDA依赖通道，阻止Ca2+进入，直到神经元部分去极化25,32。我们报告说，当通过降低沐浴介质中的细胞外[Mg2+]来促进NMDA受体激活时，在新皮层切片中，第VI层中呈现的低频序列在第II/III层的广泛水平范围内诱导了增强的反应。根据重复条件刺激的强度和记录点与刺激的距离，反应幅度比基线值增强了34-200%。与此同时，预先存在的诱发反应被增强，促进了第II/III层活动的水平扩散，导致反应出现在距离刺激1毫米以上的部位。这种增强的反应传递持续了bb22小时，并且通过改变刺激呈现的条件可以增加活性的传播，从而阻止了其诱导。我们的结论是，支持LTP的机制可以决定被感觉输入激活的新皮层的面积。
The search for mechanisms in neocortex that change synaptic efficacy and produce associative learning through activity-dependent processes has focused on the role of glutamate receptors of theN-methyl-d-aspartate (NMDA) type. NMDA receptor activation is necessary for the induction of long-term potentiation (LTP) in hippocampus12and in neocortex2. The effect of NMDA receptor activation is modulated in several ways, including Mg2+block of the NMDA-dependent channel which prevents Ca2+entry until neurons become partially depolarized25,32. We report that when NMDA receptor activation is facilitated by lowering the extracellular [Mg2+] in the bathing medium, a low-frequency train presented in layer VI induces potentiated responses throughout a wide horizontal extent of layer II/III in neocortical slices. The response amplitudes potentiated by 34–200% over baseline values depending on the intensity of the repetitive conditioning stimulus and the distance of the recording site from the stimulus. At the same time that pre-existing evoked responses were potentiated, horizontal spread of activity in layer II/III was facilitated resulting in responses appearing at sites more than 1 mm from the stimulus. This enhanced transmission of responses persisted for >2 h, and its induction was prevented by s spread of activity can be increased by altering the conditions of the stimulus presentation. We conclude that the mechanisms supporting LTP could determine the area of neocortex that is activated by a sensory input.