What is depression and why our brains so easily able to slip into it?

Is depression detectable in animals?

And when we look across the animal kingdom, do we see options beyond fight or flight?

And what does any of this have to do with measuring depression

medications in city water supplies or reward pathways in the brain or the prevalence of tuberculosis

or zapping the head with magnetic stimulation? Welcome to Inner Cosmos with me, David Eagleman.

I'm a neuroscientist and an author at Stanford.

And in these episodes, we sail deeply into our three-pound universe to understand why and how our lives look the way they do.

Thank you. lives look the way they do. Today's episode is about depression.

We are going to dive into the science behind it and we'll see what new solutions are

on the horizon.

So let me start by zooming way out. What fascinates me

is not just what the brain can accomplish in terms of our normal functioning, but also one can't

help but notice the fragility of the brain. I mean, just think about how easy it is to lose consciousness when you hit your head.

Or think about what happens when you drink alcohol and your perception and your decision-making changes.

Or you don't get enough sleep and how you behave and how you decide these can become a little different.

Or when you're hangary and

you act differently, or if you consume psychedelic drugs and your conscious experience changes entirely.

What all this tells us, I think, is that it's very easy for the system to get knocked off

its normal pathway. And what's clear is that the brain puts an enormous

amount of effort into trying to stay operating in the normal range. Now, given this context,

one area that's fascinating and of massive social importance is depression. This is a mood disorder. It affects how

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