The activity-dependent rules that govern the wiring of GABAergic interneurons are not well understood. Chandelier cells (ChCs) are a type of GABAergic interneuron that control pyramidal cell output through axo-axonic synapses that target the axon initial segment. In vivo imaging of ChCs during development uncovered a narrow window (P12-P18) over which axons arborized and formed connections. We found that increases in the activity of either pyramidal cells or individual ChCs during this temporal window result in a reversible decrease in axo-axonic connections. Voltage imaging of GABAergic transmission at the axon initial segment (AIS) showed that axo-axonic synapses were depolarizing during this period. Identical manipulations of network activity in older mice (P40-P46), when ChC synapses are inhibitory, resulted instead in an increase in axo-axonic synapses. We propose that the direction of ChC synaptic plasticity follows homeostatic rules that depend on the polarity of axo-axonic synapses.

中文翻译：

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轴突初始段的轴突突触的活动依赖性可塑性。

尚未完全了解控制GABA能性神经元连线的依赖活动的规则。枝形吊灯细胞（ChCs）是一类GABA能神经元，它通过以轴突初始节段为轴突的轴突突触控制锥体细胞的输出。在发育过程中对ChCs的体内成像发现了一个狭窄的窗口（P12-P18），轴突在该窗口上形成并形成连接。我们发现，在此时间窗口期间，锥体细胞或单个ChC的活性增加会导致轴突-轴突连接的可逆减少。轴突初始节段（AIS）的GABA能传递的电压成像显示，在此期间，轴突突突正在去极化。当ChC突触被抑制时，对老年小鼠（P40-P46）的网络活动进行相同的处理，反而导致了轴突突触突触的增加。我们建议ChC突触可塑性的方向遵循取决于轴突-突触突触极性的稳态规则。