# iaf_chs_2007 – Spike-response model used in Carandini et al. 2007¶

## Description¶

The membrane potential is the sum of stereotyped events: the postsynaptic
potentials (`V_syn`

), waveforms that include a spike and the subsequent
after-hyperpolarization (`V_spike`

) and Gaussian-distributed white noise.

The postsynaptic potential is described by alpha function where
`U_epsp`

is the maximal amplitude of the EPSP and `tau_epsp`

is the time to
peak of the EPSP.

The spike waveform is described as a delta peak followed by a membrane
potential reset and exponential decay. `U_reset`

is the magnitude of the
reset/after-hyperpolarization and `tau_reset`

is the time constant of
recovery from this hyperpolarization.

The linear subthreshold dynamics is integrated by the Exact Integration scheme [1]. The neuron dynamics is solved on the time grid given by the computation step size. Incoming as well as emitted spikes are forced to that grid.

Note

The way the noise term was implemented in the original model makes it unsuitable for simulation in NEST. The workaround was to prepare the noise signal externally prior to simulation. The noise signal, if present, has to be at least as long as the simulation.

See also [2].

## Parameters¶

The following parameters can be set in the status dictionary.

tau_epsp |
ms |
Membrane time constant |

tau_reset |
ms |
Refractory time constant |

U_epsp |
real |
Maximum amplitude of the EPSP, normalized |

U_reset |
real |
Reset value of the membrane potential, normalized |

U_noise |
real |
Noise scale, normalized |

noise |
list of real |
Noise signal |

## References¶

## Sends¶

SpikeEvent

## Receives¶

SpikeEvent, DataLoggingRequest