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Activity-Dependent Plasticity of Axo-axonic Synapses at the Axon Initial Segment

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)265-276.e6
Issue number2
Early online date10 Feb 2020
E-pub ahead of print10 Feb 2020
Published22 Apr 2020

Bibliographical note

Copyright © 2020. Published by Elsevier Inc.

King's Authors


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.

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