Bi-directional Control of Synaptic Input Summation and Spike Generation by GABAergic Inputs at the Axon Initial Segment  

作　　者：Ziwei Shang Junhao Huang Nan Liu Xiaohui Zhang 

机构地区：[1]State Key Laboratory of Cognitive Neuroscience and Learning,IDG/McGovern Institute for Brain Research,Beijing Normal University,Beijing 100875,China

出　　处：《Neuroscience Bulletin》2023年第1期1-13,共13页神经科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(32130043 and 32071025);the Interdisciplinary Research Fund of Beijing Normal University,China.

摘　　要：Differing from other subtypes of inhibitory interneuron,chandelier or axo-axonic cells form depolarizing GABAergic synapses exclusively onto the axon initial segment(AIS)of targeted pyramidal cells(PCs).However,the debate whether these AIS-GABAergic inputs produce excitation or inhibition in neuronal processing is not resolved.Using realistic NEURON modeling and electrophysiological recording of cortical layer-5 PCs,we quantitatively demonstrate that the onset-timing of AIS-GABAergic input,relative to dendritic excitatory glutamatergic inputs,determines its bi-directional regulation of the efficacy of synaptic integration and spike generation in a PC.More specifically,AIS-GABAergic inputs promote the boosting effect of voltage-activated Na+channels on summed synaptic excitation when they precede glutamatergic inputs by>15 ms,while for nearly concurrent excitatory inputs,they primarily produce a shunting inhibition at the AIS.Thus,our findings offer an integrative mechanism by which AIS-targeting interneurons exert sophisticated regulation of the input-output function in targeted PCs.

关 键 词：GABAergic inputs Axon initial segment Synaptic integration Axo-axonic cell Chandelier cell NEURON simulation Dynamic clamp 

分 类 号：R741[医药卫生—神经病学与精神病学]