# hh_cond_exp_traub – Hodgkin-Huxley model for Brette et al (2007) review¶

## Description¶

`hh_cond_exp_traub`

is an implementation of a modified Hodgkin-Huxley model.

This model was specifically developed for a major review of simulators [1], based on a model of hippocampal pyramidal cells by Traub and Miles [2]. The key differences between the current model and the model in [2] are:

This model is a point neuron, not a compartmental model.

This model includes only

`I_Na`

and`I_K`

, with simpler`I_K`

dynamics than in [2], so it has only three instead of eight gating variables; in particular, all Ca dynamics have been removed.Incoming spikes induce an instantaneous conductance change followed by exponential decay instead of activation over time.

This model is primarily provided as reference implementation for hh_coba example of the Brette et al (2007) review. Default parameter values are chosen to match those used with NEST 1.9.10 when preparing data for [1]. Code for all simulators covered is available from ModelDB [3].

Note

In this model, a spike is emitted if \(V_m \geq V_T + 30\) mV and \(V_m\) has fallen during the current time step.

To avoid multiple spikes from occurring during the falling flank of a spike, it is essential to choose a sufficiently long refractory period. Traub and Miles used \(t_{ref} = 3\) ms ([2], p 118), while we used \(t_{ref} = 2\) ms in [2].

For further details on asynchronicity in spike and firing events with Hodgkin Huxley models see here.

## Parameters¶

The following parameters can be set in the status dictionary.

V_m |
mV |
Membrane potential |

V_T |
mV |
Voltage offset that controls dynamics. For default parameters, V_T = -63mV results in a threshold around -50mV. |

E_L |
mV |
Leak reversal potential |

C_m |
pF |
Capacity of the membrane |

g_L |
nS |
Leak conductance |

tau_syn_ex |
ms |
Time constant of the excitatory synaptic exponential function |

tau_syn_in |
ms |
Time constant of the inhibitory synaptic exponential function |

t_ref |
ms |
Duration of refractory period (see Note). |

E_ex |
mV |
Excitatory synaptic reversal potential |

E_in |
mV |
Inhibitory synaptic reversal potential |

E_Na |
mV |
Sodium reversal potential |

g_Na |
nS |
Sodium peak conductance |

E_K |
mV |
Potassium reversal potential |

g_K |
nS |
Potassium peak conductance |

I_e |
pA |
External input current |

## References¶

## Sends¶

SpikeEvent

## Receives¶

SpikeEvent, CurrentEvent, DataLoggingRequest