Auryn was written to simulate networks of spiking neurons. To facilitate the process of building your own network simulation, Auryn handles neurons in populations and synaptic connections between them. For instance, if you were to create a balanced network model you do not have to create individual neurons, but you would create two populations: one for the excitatory neurons and for the inhibitory neurons. You would then connect them using Connection objects that operate on those populations. This allows to specify network models in a relatively compact notation (see for example Vogels COBA network).