# brainpy.dyn.channels.Ih#

class brainpy.dyn.channels.Ih(size, g_max=10.0, E=- 90.0, phi=1.0, method='exp_auto', name=None)[source]#

The hyperpolarization-activated cation current model.

The hyperpolarization-activated cation current model is adopted from (Huguenard, et, al., 1992) 1. Its dynamics is given by:

\begin{split}\begin{aligned} I_h &= g_{\mathrm{max}} p \\ \frac{dp}{dt} &= \phi \frac{p_{\infty} - p}{\tau_p} \\ p_{\infty} &=\frac{1}{1+\exp ((V+75) / 5.5)} \\ \tau_{p} &=\frac{1}{\exp (-0.086 V-14.59)+\exp (0.0701 V-1.87)} \end{aligned}\end{split}

where $$\phi=1$$ is a temperature-dependent factor.

Parameters
• g_max (float) – The maximal conductance density ($$mS/cm^2$$).

• E (float) – The reversal potential (mV).

• phi (float) – The temperature-dependent factor.

References

1

Huguenard, John R., and David A. McCormick. “Simulation of the currents involved in rhythmic oscillations in thalamic relay neurons.” Journal of neurophysiology 68, no. 4 (1992): 1373-1383.

__init__(size, g_max=10.0, E=- 90.0, phi=1.0, method='exp_auto', name=None)[source]#

Methods

 __init__(size[, g_max, E, phi, method, name]) current(V) derivative(p, t, V) 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. register_delay(name, delay_step, delay_target) Register delay variable. register_implicit_nodes(nodes) register_implicit_vars(variables) reset(V) Reset function which reset the whole variables in the model. 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, V) The function to specify the updating rule. vars([method, level, include_self]) Collect all variables in this node and the children nodes.

Attributes

 global_delay_targets global_delay_vars name steps