Synapses class

(Shortest import: from brian2 import Synapses)

class brian2.synapses.synapses.Synapses(source, target=None, model=None, on_pre=None, pre=None, on_post=None, post=None, connect=None, delay=None, on_event='spike', multisynaptic_index=None, namespace=None, dtype=None, codeobj_class=None, dt=None, clock=None, order=0, method=('exact', 'euler', 'heun'), method_options=None, name='synapses*')

Bases: brian2.groups.group.Group

Class representing synaptic connections.

Creating a new Synapses object does by default not create any synapses, you have to call the Synapses.connect method for that.

Attributes

N_incoming_post	The number of incoming synapses for each neuron in the post-synaptic group.
N_outgoing_pre	The number of outgoing synapses for each neuron in the pre-synaptic group.
_connect_called	remember whether connect was called to raise an error if an assignment to a synaptic variable is attempted without a preceding connect.
_pathways	List of all SynapticPathway objects
_registered_variables	Set of Variable objects that should be resized when the number of synapses changes
_synaptic_updaters	List of names of all updaters, e.g.
delay	The presynaptic delay (if a pre-synaptic pathway exists).
delay_	The presynaptic delay without unit information (if apre-synaptic pathway exists).
events	“Events” for all the pathways
state_updater	Performs numerical integration step
subexpression_updater	Update the “constant over a time step” subexpressions
summed_updaters	“Summed variable” mechanism – sum over all synapses of a pre-/postsynaptic target

Methods

before_run(run_namespace)	Optional method to prepare the object before a run.
check_variable_write(variable)	Checks that Synapses.connect has been called before setting a synaptic variable.
connect([condition, i, j, p, n, …])	Add synapses.
register_variable(variable)	Register a DynamicArray to be automatically resized when the size of the indices change.
unregister_variable(variable)	Unregister a DynamicArray from the automatic resizing mechanism.
verify_dependencies(eq, eq_type, deps, …)	Helper function to verify that event-driven equations do not depend on clock-driven equations and the other way round.

Details

N_incoming_post

The number of incoming synapses for each neuron in the post-synaptic group.

N_outgoing_pre

The number of outgoing synapses for each neuron in the pre-synaptic group.

_connect_called

remember whether connect was called to raise an error if an assignment to a synaptic variable is attempted without a preceding connect.

_pathways

List of all SynapticPathway objects

_registered_variables

Set of Variable objects that should be resized when the number of synapses changes

_synaptic_updaters

List of names of all updaters, e.g. [‘pre’, ‘post’]

delay

The presynaptic delay (if a pre-synaptic pathway exists).

delay_

The presynaptic delay without unit information (if apre-synaptic pathway exists).

events

“Events” for all the pathways

state_updater

Performs numerical integration step

subexpression_updater

Update the “constant over a time step” subexpressions

summed_updaters

“Summed variable” mechanism – sum over all synapses of a pre-/postsynaptic target

before_run(run_namespace)

Optional method to prepare the object before a run.

Called by Network.after_run before the main simulation loop starts.

check_variable_write(variable)

Checks that Synapses.connect has been called before setting a synaptic variable.

connect(condition=None, i=None, j=None, p=1.0, n=1, skip_if_invalid=False, namespace=None, level=0)

Add synapses.

See Synapses for details.

register_variable(variable)

Register a DynamicArray to be automatically resized when the size of the indices change. Called automatically when a SynapticArrayVariable specifier is created.

unregister_variable(variable)

Unregister a DynamicArray from the automatic resizing mechanism.

static verify_dependencies(eq, eq_type, deps, should_not_depend_on, should_not_depend_on_name)

Helper function to verify that event-driven equations do not depend on clock-driven equations and the other way round.