BLOCKADE OF ACTION-POTENTIAL ACTIVITY ALTERS INITIAL ARBORIZATION OF THALAMIC AXONS WITHIN CORTICAL LAYER-4
BLOCKADE OF ACTION-POTENTIAL ACTIVITY ALTERS INITIAL ARBORIZATION OF THALAMIC AXONS WITHIN CORTICAL LAYER-4
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DOI：
10.1073/pnas.92.24.11244
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发表时间：
1995-11-21
影响因子：
11.1
通讯作者：
SHATZ, CJ
中科院分区：
文献类型：
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作者：
HERRMANN, K;SHATZ, CJ
在神经系统发育过程中，连接的形成一般认为有一个不需要神经活动的早期阶段和一个依赖活动的后期阶段。轴突寻径和目标选择的初始过程被认为不需要神经活动，而后来的连接微调到最终的成年模式则需要。我们报告了一个明显的例外，即丘脑轴突在发育的早期似乎需要动作电位活动，以便与大脑皮层第4层的最终目标神经元形成适当的终端树突模式。在猫视觉丘脑轴突向初级视觉皮层发育的2周胎儿期，钠动作电位的阻断阻止了外侧膝状核轴突在第4层内正常发生的分支。这一观察结果表明，动作电位活动在大脑皮层发育中的作用远早于先前的猜测，在睁眼前几周，以及众所周知的轴突末端乔木的活动依赖性重组过程的开始，导致眼优势柱的形成。
In the formation of connections during the development of the nervous system, it is generally accepted that there is an early phase not requiring neural activity and a later activity-dependent phase. The initial processes of axonal pathfinding and target selection are not thought to require neural activity, whereas the later fine-tuning of connections into their final adult patterns does. We report an apparent exception to this rule in which action potential activity seems to be required very early in development for thalamic axons to form appropriate patterns of terminal arborizations with their ultimate target neurons in layer 4 of the cerebral cortex. Blockade of sodium action potentials during the 2-week fetal period when visual thalamic axons initially grow into the primary visual cortex in cats prevents the normally occurring branching of lateral geniculate nucleus axons within layer 4. This observation implies a role for action-potential activity in cerebral cortical development far earlier than previously suspected, weeks before eye-opening and the onset of the well-known process of activity-dependent reorganization of axonal terminal arbors that leads to the formation of ocular dominance columns.