The Second Brain

[HUMAN] I thought I was alone in here Just one me, one mind, one brain on a chair

[GUT] NOPE There are TRILLIONS of us in your belly We're real And we have OPINIONS

[HUMAN] Wait, what?

[GUT] We're tiny tiny BACTERIA A whole zoo A garden, an ecosystem Your gut is our city

[HUMAN] You live IN me?

[GUT] We pay rent We make vitamins for you We break down food you can't break down We train your immune system

[HUMAN] That's nice and all But how does that make you a SECOND BRAIN

[GUT] Because we TALK to your first brain There's a wire — the vagus nerve — Belly to brain Brain to belly

We send chemical messages Up the wire And your brain LISTENS A LOT

The second brain The second brain Living in your belly Sending up the line

The second brain The second brain You think the head's in charge The gut has half the say

[HUMAN] What do you guys SAY up the wire?

[GUT] A bunch of things Sometimes we make serotonin The happiness chemical NINETY percent of it is made down here

[HUMAN] NINETY?

[GUT] Ninety percent We also bug you about hunger Mood Whether you're stressed Whether you slept

[HUMAN] So when I'm cranky after junk food —

[GUT] That's us starving Our garden gets weeds The friendly bacteria die back The grouchy ones move in

[HUMAN] And when I eat fiber and veggies —

[GUT] We THROW A PARTY Our garden grows We send happy signals up the wire You feel good for reasons you can't name

The second brain The second brain Trillion-celled coworker Riding in your gut

The second brain The second brain Feed it well — it talks well Feed it junk — it talks junk

[BOTH] Brain and gut, gut and brain Gut and brain, brain and gut Two of us thinking At the same time About the same kid

[HUMAN] So when my stomach has a "feeling" about something —

[GUT] We had it first Then we sent it up Trust the wire sometimes We've got DATA

[GUT] (fading out, glitchy) Two — brains — two — brains — two — brains — two — brains —

[HUMAN] Cool Hi down there