The unique collection of connected neurons that makes up a particular brain; or a system that models or emulates this, in order to attempt to create artificial intelligence. The difference between neurons and, say, network nodes is that neurons are highly connected and “not digital” – they may or may not fire based on the excitation energy from the connected neurons and “ephatic coupling” (see synapse).

In contrast, a neuronal circuit is a functional entity of interconnected neurons that influence each other (similar to a control loop in cybernetics).