From 045ae69c4252b78762329c607a21a60ddb23bb93 Mon Sep 17 00:00:00 2001 From: EnfxcFCb6 Date: Wed, 9 Jul 2025 16:12:39 -0400 Subject: [PATCH] Standardized README to Markdown format --- README.md | 23 +++++++++++++++++++++++ index.html | 49 ------------------------------------------------- 2 files changed, 23 insertions(+), 49 deletions(-) create mode 100644 README.md delete mode 100644 index.html diff --git a/README.md b/README.md new file mode 100644 index 0000000..005fb49 --- /dev/null +++ b/README.md @@ -0,0 +1,23 @@ +# For the paper: + +Platkiewicz J, Brette R (2010) A threshold equation for action potential initiation. *PLoS Comput Biol* 6:e1000850 + +## Abstract: + +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. + +A brian simulator model is available at this web page: + +[http://briansimulator.org/docs/examples-frompapers_Plakiewicz_Brette_2010.html](http://briansimulator.org/docs/examples-frompapers_Plakiewicz_Brette_2010.html) + +The simulation generates Figure 7 from the paper: + +![screenshot](./screenshot.png) + +This simulation requires Brian which can be downloaded and installed from the instructions available at [http://www.briansimulator.org/](http://www.briansimulator.org/) + +For support on installing and using Brian simulations there is a support group at [https://groups.google.com/group/briansupport](https://groups.google.com/group/briansupport). + +--- + +2025-07-09: Converted README to Markdown. \ No newline at end of file diff --git a/index.html b/index.html deleted file mode 100644 index d10f917..0000000 --- a/index.html +++ /dev/null @@ -1,49 +0,0 @@ -
-For the paper:
-
-Platkiewicz J, Brette R (2010) A threshold equation for action
-potential initiation. PLoS Comput Biol 6:e1000850
-
-Abstract:
-
-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.
-
-A brian simulator model is available at this web page:
-
-http://briansimulator.org/docs/examples-frompapers_Plakiewicz_Brette_2010.html
-
-The simulation generates Figure 7 from the paper:
-
-screenshot
-
-This simulation requires Brian which can be downloaded and installed
-from the instructions available at http://www.briansimulator.org/
-
-For support on installing and using Brian simulations there is a
-support group at https://groups.google.com/group/briansupport.
-