quantal_stp_synapse – Probabilistic synapse model with short term plasticity

Description

This synapse model implements synaptic short-term depression and short-term facilitation according to the quantal release model described by Fuhrmann et al. [1] and Loebel et al. [2].

Each presynaptic spike will stochastically activate a fraction of the available release sites. This fraction is binomialy distributed and the release probability per site is governed by the Fuhrmann et al. (2002) model. The solution of the differential equations is taken from Maass and Markram 2002 [3].

The connection weight is interpreted as the maximal weight that can be obtained if all n release sites are activated.

Warning

This synaptic plasticity rule does not take precise spike timing into account. When calculating the weight update, the precise spike time part of the timestamp is ignored.

Parameters

The following parameters can be set in the status dictionary:

U	real	Maximal fraction of available resources [0,1], default = 0.5
u	real	Available fraction of resources [0,1], default = U
n	integer	Total number of release sites, default = 1
a	integer	Number of available release sites, default = n
tau_fac	ms	Time constant for facilitation, default = 0 (off)
tau_rec	ms	Time constant for depression, default = 800

References

[1]

Fuhrmann G, Segev I, Markram H, Tsodyks MV (2002). Coding of temporal information by activity-dependent synapses. Journal of neurophysiology, 87(1):140-8. DOI: https://doi.org/10.1152/jn.00258.2001

[2]

Loebel A, Silberberg G, Helbig D, Markram H, Tsodyks MV, Richardson MJE (2009). Multiquantal release underlies the distribution of synaptic efficacies in the neocortex. Frontiers in Computational Neuroscience, 3, 27. DOI: https://doi.org/10.3389/neuro.10.027.2009

[3]

Maass W, Markram H (2002). Synapses as dynamic memory buffers. Neural Networks, 15(2):155-161. DOI: https://doi.org/10.1016/S0893-6080(01)00144-7

Transmits

SpikeEvent

See also

Synapse, Short-Term Plasticity

Examples using this model

• Example for the quantal_stp_synapse