# 3.8. Specific Populations¶

ANNarchy provides a set of predefined Projection objects to ease the definition of standard networks.

## 3.8.1. Class CurrentInjection¶

class ANNarchy.CurrentInjection(pre, post, target, name=None, copied=False)[source]

Inject current from a rate-coded population into a spiking population.

The pre-synaptic population must be be rate-coded, the post-synaptic one must be spiking, both must have the same size and no plasticity is allowed.

For each post-synaptic neuron, the current g_target will be set at each time step to the firing rate r of the pre-synaptic neuron with the same rank.

The projection must be connected with connect_current(), which takes no parameter and does not accept delays. It is equivalent to connect_one_to_one(weights=1).

Example:

inp = Population(100, Neuron(equations="r = sin(t)"))

pop = Population(100, Izhikevich)

proj = CurrentInjection(inp, pop, 'exc')
proj.connect_current()


Parameters:

• pre: pre-synaptic population.
• post: post-synaptic population.
• target: type of the connection.