Brain ‘circuit’ is a very common term today. This is great - but there’s still ambiguity about what exactly a “circuit” is.
It’s obvious more than a region - most of us are in agreement there - but how much more is still not-consensus.
Components of a Circuit
Let’s first talk about the core components of any circuit - informed directly by the authoritative field that studies circuits: electrical and computer engineering.
A circuit tends to consist of:
- A list of Parts - things like resistors, motor regions, executive control effectors, etc.
- A connectivity between the Parts - we’ll call this the topology.
- An embedding of the Parts + Topology into “real space” - we’ll call this the circuit geometry.
- A set of conservation laws that govern how something flows on the circuit - we’ll call this the circuit symmetry.
That last part, with the conservation laws is so critical - I’ll tend to argue that it’s the most important part of a “circuit” that differentiates it from a simple structural loop and/or a network.