A threshold equation for action potential initiation.

In central neurons, the threshold for spike initiation can depend on the stimulus and varies between cells and between recording sites in a given cell, but it is unclear what mechanisms underlie this variability. Properties of ionic channels are likely to play a role in threshold modulation. We exam...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Jonathan Platkiewicz, Romain Brette
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2010
Materias:	Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/e8f8f5ff8b5f4d94bc8bab7f33d8471b
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:e8f8f5ff8b5f4d94bc8bab7f33d8471b
record_format	dspace
spelling	oai:doaj.org-article:e8f8f5ff8b5f4d94bc8bab7f33d8471b2021-12-02T19:58:17ZA threshold equation for action potential initiation.1553-734X1553-735810.1371/journal.pcbi.1000850https://doaj.org/article/e8f8f5ff8b5f4d94bc8bab7f33d8471b2010-07-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/20628619/pdf/?tool=EBIhttps://doaj.org/toc/1553-734Xhttps://doaj.org/toc/1553-7358In central neurons, the threshold for spike initiation can depend on the stimulus and varies between cells and between recording sites in a given cell, but it is unclear what mechanisms underlie this variability. Properties of ionic channels are likely to play a role in threshold modulation. We examined in models the influence of Na channel activation, inactivation, slow voltage-gated channels and synaptic conductances on spike threshold. We propose a threshold equation which quantifies the contribution of all these mechanisms. It provides an instantaneous time-varying value of the threshold, which applies to neurons with fluctuating inputs. We deduce a differential equation for the threshold, similar to the equations of gating variables in the Hodgkin-Huxley formalism, which describes how the spike threshold varies with the membrane potential, depending on channel properties. We find that spike threshold depends logarithmically on Na channel density, and that Na channel inactivation and K channels can dynamically modulate it in an adaptive way: the threshold increases with membrane potential and after every action potential. Our equation was validated with simulations of a previously published multicompartemental model of spike initiation. Finally, we observed that threshold variability in models depends crucially on the shape of the Na activation function near spike initiation (about -55 mV), while its parameters are adjusted near half-activation voltage (about -30 mV), which might explain why many models exhibit little threshold variability, contrary to experimental observations. We conclude that ionic channels can account for large variations in spike threshold.Jonathan PlatkiewiczRomain BrettePublic Library of Science (PLoS)articleBiology (General)QH301-705.5ENPLoS Computational Biology, Vol 6, Iss 7, p e1000850 (2010)
institution	DOAJ
collection	DOAJ
language	EN
topic	Biology (General) QH301-705.5
spellingShingle	Biology (General) QH301-705.5 Jonathan Platkiewicz Romain Brette A threshold equation for action potential initiation.
description	In central neurons, the threshold for spike initiation can depend on the stimulus and varies between cells and between recording sites in a given cell, but it is unclear what mechanisms underlie this variability. Properties of ionic channels are likely to play a role in threshold modulation. We examined in models the influence of Na channel activation, inactivation, slow voltage-gated channels and synaptic conductances on spike threshold. We propose a threshold equation which quantifies the contribution of all these mechanisms. It provides an instantaneous time-varying value of the threshold, which applies to neurons with fluctuating inputs. We deduce a differential equation for the threshold, similar to the equations of gating variables in the Hodgkin-Huxley formalism, which describes how the spike threshold varies with the membrane potential, depending on channel properties. We find that spike threshold depends logarithmically on Na channel density, and that Na channel inactivation and K channels can dynamically modulate it in an adaptive way: the threshold increases with membrane potential and after every action potential. Our equation was validated with simulations of a previously published multicompartemental model of spike initiation. Finally, we observed that threshold variability in models depends crucially on the shape of the Na activation function near spike initiation (about -55 mV), while its parameters are adjusted near half-activation voltage (about -30 mV), which might explain why many models exhibit little threshold variability, contrary to experimental observations. We conclude that ionic channels can account for large variations in spike threshold.
format	article
author	Jonathan Platkiewicz Romain Brette
author_facet	Jonathan Platkiewicz Romain Brette
author_sort	Jonathan Platkiewicz
title	A threshold equation for action potential initiation.
title_short	A threshold equation for action potential initiation.
title_full	A threshold equation for action potential initiation.
title_fullStr	A threshold equation for action potential initiation.
title_full_unstemmed	A threshold equation for action potential initiation.
title_sort	threshold equation for action potential initiation.
publisher	Public Library of Science (PLoS)
publishDate	2010
url	https://doaj.org/article/e8f8f5ff8b5f4d94bc8bab7f33d8471b
work_keys_str_mv	AT jonathanplatkiewicz athresholdequationforactionpotentialinitiation AT romainbrette athresholdequationforactionpotentialinitiation AT jonathanplatkiewicz thresholdequationforactionpotentialinitiation AT romainbrette thresholdequationforactionpotentialinitiation
_version_	1718375813321064448

A threshold equation for action potential initiation.

Ejemplares similares