urbanczik_synapse – Synapse type for a plastic synapse after Urbanczik and Senn
===============================================================================

Description
+++++++++++

``urbanczik_synapse`` is a connector to create Urbanczik synapses as defined in
[1]_ that can connect suitable :ref:`multicompartment models
<multicompartment-models>`. In contrast to most STDP models, the synaptic weight
depends on the postsynaptic dendritic potential, in addition to the pre- and
postsynaptic spike timing.

Urbanczik synapses require the archiving of the dendritic membrane potential
which is continuous in time. Therefore they can only be connected to neuron
models that are capable of doing this archiving. So far, the only compatible
model is :doc:`pp_cond_exp_mc_urbanczik <pp_cond_exp_mc_urbanczik>`.

.. warning::

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

Parameters
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=========   ====   =========================================================
eta         real   Learning rate
tau_Delta   real   Time constant of low pass filtering of the weight change
Wmax        real   Maximum allowed weight
Wmin        real   Minimum allowed weight
=========   ====   =========================================================

All other parameters are stored in the neuron models that are compatible
with the Urbanczik synapse.

Transmits
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SpikeEvent

References
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.. [1] Urbanczik R. and Senn W (2014). Learning by the dendritic
       prediction of somatic spiking. Neuron, 81:521 - 528.
       https://doi.org/10.1016/j.neuron.2013.11.030

See also
++++++++
:doc:`Synapse <index_synapse>`, :doc:`Spike-Timing-Dependent Plasticity <index_spike-timing-dependent plasticity>`