# diffusion_connection – Synapse type for instantaneous rate connections between neurons of type siegert_neuron¶

## Description¶

`diffusion_connection`

is a connector to create
instantaneous connections between neurons of type `siegert_neuron`

. The
connection type is identical to type `rate_connection_instantaneous`

for instantaneous rate connections except for the two parameters
`drift_factor`

and `diffusion_factor`

substituting the parameter weight.

These two factor origin from the mean-field reduction of networks of
leaky-integrate-and-fire neurons. In this reduction the input to the
neurons is characterized by its mean and its variance. The mean is
obtained by a sum over presynaptic activities (e.g as in eq.28 in
[1]), where each term of the sum consists of the presynaptic activity
multiplied with the `drift_factor`

. Similarly, the variance is obtained
by a sum over presynaptic activities (e.g as in eq.29 in [1]), where
each term of the sum consists of the presynaptic activity multiplied
with the `diffusion_factor`

. Note that in general the drift and
diffusion factors might differ from the ones given in eq. 28 and 29.,
for example in case of a reduction on the single neuron level or in
case of distributed in-degrees (see discussion in chapter 5.2 of [1])

The values of the parameters delay and weight are ignored for connections of this type.

## Transmits¶

DiffusionConnectionEvent