Dr. David Berson

That is, they're looking out into the world

using a completely different set of sensors.

They're using the same sensors that would feel the warmth on your face if you stood in front of a bonfire, except evolution has given them this very nice specialized system that lets them image where the heat's coming from.

You can sort of do that anyway, right?

If you walk around the fire, you can feel where the fire is from the heat hitting your face.

It's one of the major ways.

And in fact, they use vision as well.

And they bring these two systems together in the same place, in this tectum region, this brainstem.

Now the brain is confused and that may be where your motion sickness comes from.

So it's great to have, as a brain, it's great to have as many sources of information as you can have.

Just like if you're a spy or a journalist, you don't want as much information as you can get about what's out there.

But if things conflict, that's problematic, right?

Your sources are giving you different information about what's going on.

Now you've got a problem on your hands.

What do you publish?

Yeah, so I mean, the basal ganglia are sitting deep in what you would call the forebrain, so the highest levels of the brain, and it's deeply intertwined with cortical function.

The cortex can't really do what it needs to do without the help of the basal ganglia and vice versa.

And in a way, you can think about this logically as saying, if you have the ability to withhold behavior or to execute it, how do you decide which to do?

Well, the cortex is gonna have to do that thinking for you.

You have to be looking at all the contingencies of your situation to decide, is this a crazy move or is this a really smart investment right now or, you know, what?