**Name:**

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 subthresold 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.

**Parameters:**

The following parameters can be set in the status dictionary.

tau_epsp double - Membrane time constant in ms.

tau_reset double - Refractory time constant in ms.

U_epsp double - Maximum amplitude of the EPSP. Normalized.

U_reset double - Reset value of the membrane potential. Normalized.

U_noise double - Noise scale. Normalized.

noise vector- Noise signal.

**Receives:**

SpikeEvent, DataLoggingRequest

**Sends:**

SpikeEvent

**Remarks:**

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.

**References:**

[1] Carandini M, Horton JC, Sincich LC (2007) Thalamic filtering of retinal

spike trains by postsynaptic summation. J Vis 7(14):20,1-11.

[2] Rotter S & Diesmann M (1999) Exact simulation of time-invariant linear

systems with applications to neuronal modeling. Biologial Cybernetics

81:381-402.

**Author:**

Thomas Heiberg, Birgit Kriener

**FirstVersion:**

May 2012

**Source:**

/home/graber/work-nest/nest-git/nest-simulator/models/iaf_chs_2007.h