Okay, so your second brain isn't really a brain at all. It's more of a 'brain' that happens to live in our stomach and helps regulate an amazing number of feelings and emotions. Known as the enteric nervous system, this is the mechanism behind all those "I'm going with my gut on this", "I'm having a gut reaction", and "I had a gut-wrenching experience" phrases that have become so much a part of our everyday parlance. 

You probably already know that we have a whole lot of neurons - nerve cells that form the basis of our central and peripheral nervous systems - in our spine, but did you know that we have the same number lining the long tube of our gut? The complex make-up of our gut means it's able to create intense cravings - why do I suddenly need a cheeseburger immediately? - without even communicating with our actual brain, says Vanessa Hill in the latest episode of BrainCraft.

And it's not just the neurons packed into our stomach that pretty much tell us what to do, says Vanessa - the buzzing microcosm inside is also busy exerting its influence.

Called the microbiome, this colony of bacteria is determined by many factors, such as how old you are, where you live, what you eat, and even how stressed-out you are, and it can communicate with our central nervous system to control everything from how anxious you are about a particular task, to how likely you are to approach things with Kimmy Schmidt levels of positivity (okay, maybe not that high). And we're only just now figuring out the extent of its influence over us.

Watch the latest episode of BrainCraft above to find out what's actually going on down there, and if you happen to be craving chicken nuggets dipped in Sprite, you now know what part of you is to blame.