Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus

S. Kim, PLoS One 9 (2014).

Download
OA 5.18 MB

Journal Article | Published | English
Department
Abstract
Oriens-lacunosum moleculare (O-LM) interneurons in the CA1 region of the hippocampus play a key role in feedback inhibition and in the control of network activity. However, how these cells are efficiently activated in the network remains unclear. To address this question, I performed recordings from CA1 pyramidal neuron axons, the presynaptic fibers that provide feedback innervation of these interneurons. Two forms of axonal action potential (AP) modulation were identified. First, repetitive stimulation resulted in activity-dependent AP broadening. Broadening showed fast onset, with marked changes in AP shape following a single AP. Second, tonic depolarization in CA1 pyramidal neuron somata induced AP broadening in the axon, and depolarization-induced broadening summated with activity-dependent broadening. Outsideout patch recordings from CA1 pyramidal neuron axons revealed a high density of a-dendrotoxin (α-DTX)-sensitive, inactivating K+ channels, suggesting that K+ channel inactivation mechanistically contributes to AP broadening. To examine the functional consequences of axonal AP modulation for synaptic transmission, I performed paired recordings between synaptically connected CA1 pyramidal neurons and O-LM interneurons. CA1 pyramidal neuron-O-LM interneuron excitatory postsynaptic currents (EPSCs) showed facilitation during both repetitive stimulation and tonic depolarization of the presynaptic neuron. Both effects were mimicked and occluded by α-DTX, suggesting that they were mediated by K+ channel inactivation. Therefore, axonal AP modulation can greatly facilitate the activation of O-LM interneurons. In conclusion, modulation of AP shape in CA1 pyramidal neuron axons substantially enhances the efficacy of principal neuron-interneuron synapses, promoting the activation of O-LM interneurons in recurrent inhibitory microcircuits.
Publishing Year
Date Published
2014-11-19
Journal Title
PLoS One
Volume
9
Issue
11
Article Number
0113124
IST-REx-ID

Cite this

Kim S. Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus. PLoS One. 2014;9(11). doi:10.1371/journal.pone.0113124
Kim, S. (2014). Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus. PLoS One, 9(11). https://doi.org/10.1371/journal.pone.0113124
Kim, Sooyun. “Action Potential Modulation in CA1 Pyramidal Neuron Axons Facilitates OLM Interneuron Activation in Recurrent Inhibitory Microcircuits of Rat Hippocampus.” PLoS One 9, no. 11 (2014). https://doi.org/10.1371/journal.pone.0113124.
S. Kim, “Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus,” PLoS One, vol. 9, no. 11, 2014.
Kim S. 2014. Action potential modulation in CA1 pyramidal neuron axons facilitates OLM interneuron activation in recurrent inhibitory microcircuits of rat hippocampus. PLoS One. 9(11).
Kim, Sooyun. “Action Potential Modulation in CA1 Pyramidal Neuron Axons Facilitates OLM Interneuron Activation in Recurrent Inhibitory Microcircuits of Rat Hippocampus.” PLoS One, vol. 9, no. 11, 0113124, Public Library of Science, 2014, doi:10.1371/journal.pone.0113124.
All files available under the following license(s):
Creative Commons License:
CC-BY-SACreative Commons Attribution-ShareAlike 4.0 International Public License (CC BY-SA 4.0)
Main File(s)
Access Level
OA Open Access
Last Uploaded
2018-12-12T10:14:52Z


Export

Marked Publications

Open Data IST Research Explorer

Search this title in

Google Scholar