Synapse
Synapse(self,
='',
parameters='',
equations=None,
psp='sum',
operation=None,
pre_spike=None,
post_spike=None,
pre_axon_spike=None,
functions=None,
pruning=None,
creating=None,
name=None,
description={},
extra_values )
Base class to define a synapse model.
Synapses expect parameters
as a dictionary and equations
as a list of variable updates (including w
if there is synaptic plasticity).
Rate-coded synapses can define psp
and operation
to modify synaptic transmission:
= ann.Synapse(
nonlinear_synapse = "log( (pre.r * w + 1 ) / (pre.r * w - 1) )",
psp = 'max',
operation )
Spiking synapses can define event-based rules, such as pre_spike
(a pre-synaptic spike arrives at the synapse) and post_spike
(the post-synaptic neuron emits a spike):
= ann.Synapse(
STDP = dict(
parameters = 10.0,
tau_pre = 10.0,
tau_post = 0.01,
cApre = 0.0105,
cApost = 0.01,
wmax
),= [
equations 'tau_pre * dApre/dt = - Apre', method='event-driven'),
ann.Variable('tau_post * dApost/dt = - Apost', method='event-driven'),
ann.Variable(
],= '''
pre_spike g_target += w
Apre += cApre * wmax
w = clip(w - Apost, 0.0 , wmax)
''',
= '''
post_spike Apost += cApost * wmax
w = clip(w + Apre, 0.0 , wmax)
'''
)
Parameters
Name | Type | Description | Default |
---|---|---|---|
parameters | str | dict | dictionary of parameters and their initial value. | '' |
equations | str | list | list of equations defining the temporal evolution of variables. | '' |
psp | str | continuous influence of a single synapse on the post-synaptic neuron (default for rate-coded: w*pre.r ). Synaptic transmission in spiking synapses occurs in pre_spike . |
None |
operation | str | operation (sum, max, min, mean) performed by the post-synaptic neuron on the individual psp (rate-coded only). | 'sum' |
pre_spike | str | list | updating of variables when a pre-synaptic spike is received (spiking only). | None |
post_spike | str | list | updating of variables when a post-synaptic spike is emitted (spiking only). | None |
pre_axon_spike | str | updating of variables when an axonal spike was emitted (spiking only, default None). The usage of this arguments prevents the application of learning rules. | None |
functions | str | additional functions used in the equations. | None |
pruning | str | Condition for pruning the synapse. | None |
creating | str | Condition for creating the synapse. | None |
name | str | name of the synapse type (used for reporting only). | None |
description | str | short description of the synapse type (used for reporting). | None |