brainpy.dyn.synapses.ExpCOBA

class brainpy.dyn.synapses.ExpCOBA(pre, post, conn, conn_type='sparse', g_max=1.0, tau=8.0, E=0.0, delay_step=None, method='exp_auto', name=None)

Conductance-based exponential decay synapse model.

Model Descriptions

The conductance-based exponential decay synapse model is similar with the current-based exponential decay synapse model, except the expression which output onto the post-synaptic neurons:

\[I_{syn}(t) = g_{\mathrm{syn}}(t) (V(t)-E)\]

where \(V(t)\) is the membrane potential of the post-synaptic neuron, \(E\) is the reversal potential.

Model Examples

• (Brette, et, al., 2007) COBA

• (Brette, et, al., 2007) COBAHH

>>> import brainpy as bp
>>> import matplotlib.pyplot as plt
>>>
>>> neu1 = bp.dyn.HH(1)
>>> neu2 = bp.dyn.HH(1)
>>> syn1 = bp.dyn.ExpCOBA(neu1, neu2, bp.connect.All2All(), E=0.)
>>> net = bp.dyn.Network(pre=neu1, syn=syn1, post=neu2)
>>>
>>> runner = bp.dyn.DSRunner(net, inputs=[('pre.input', 5.)], monitors=['pre.V', 'post.V', 'syn.g'])
>>> runner.run(150.)
>>>
>>> fig, gs = bp.visualize.get_figure(2, 1, 3, 8)
>>> fig.add_subplot(gs[0, 0])
>>> plt.plot(runner.mon.ts, runner.mon['pre.V'], label='pre-V')
>>> plt.plot(runner.mon.ts, runner.mon['post.V'], label='post-V')
>>> plt.legend()
>>>
>>> fig.add_subplot(gs[1, 0])
>>> plt.plot(runner.mon.ts, runner.mon['syn.g'], label='g')
>>> plt.legend()
>>> plt.show()

(Source code, png, hires.png, pdf)

Parameters

• pre (NeuGroup) – The pre-synaptic neuron group.

• post (NeuGroup) – The post-synaptic neuron group.

• conn (optional, ndarray, JaxArray, dict of (str, ndarray), TwoEndConnector) – The synaptic connections.

• conn_type (str) – The connection type used for model speed optimization. It can be sparse and dense. The default is sparse.

• delay_step (int, ndarray, JaxArray, Initializer, Callable) – The delay length. It should be the value of \(\mathrm{delay\_time / dt}\).

• E (float, JaxArray, ndarray) – The reversal potential for the synaptic current. [mV]

• tau (float, JaxArray, ndarray) – The time constant of decay. [ms]

• g_max (float, ndarray, JaxArray, Initializer, Callable) – The synaptic strength (the maximum conductance). Default is 1.

• name (str) – The name of this synaptic projection.

• method (str) – The numerical integration methods.

References

1

Sterratt, David, Bruce Graham, Andrew Gillies, and David Willshaw. “The Synapse.” Principles of Computational Modelling in Neuroscience. Cambridge: Cambridge UP, 2011. 172-95. Print.

__init__(pre, post, conn, conn_type='sparse', g_max=1.0, tau=8.0, E=0.0, delay_step=None, method='exp_auto', name=None)

Methods

__init__(pre, post, conn[, conn_type, ...])
check_post_attrs(*attrs)	Check whether post group satisfies the requirement.
check_pre_attrs(*attrs)	Check whether pre group satisfies the requirement.
get_delay_data(name, delay_step, *indices)	Get delay data according to the provided delay steps.
ints([method])	Collect all integrators in this node and the children nodes.
load_states(filename[, verbose])	Load the model states.
nodes([method, level, include_self])	Collect all children nodes.
output(g_post)
register_delay(name, delay_step, delay_target)	Register delay variable.
register_implicit_nodes(nodes)
register_implicit_vars(variables)
reset()	Reset function which reset the whole variables in the model.
reset_delay(name, delay_target)	Reset the delay variable.
save_states(filename[, variables])	Save the model states.
train_vars([method, level, include_self])	The shortcut for retrieving all trainable variables.
unique_name([name, type_])	Get the unique name for this object.
update(t, dt)	The function to specify the updating rule.
update_delay(name, delay_data)	Update the delay according to the delay data.
vars([method, level, include_self])	Collect all variables in this node and the children nodes.

Attributes

global_delay_vars
name
steps