What's the best way to think about the brain?
It's insanely complicated,
everything connects to everything.
Amid all that complexity,
functionally, it's very easy to think of the brain
as coming in three functional layers.
This is a broadly simplifying way
to think about aspects of brain function
when it comes to behavior.
This is highly schematic,
the brain really doesn't come in three layers.
But one can think of the first most,
the bottom most, the most ancient
as being what's often termed the reptilian brain.
We've got the same wiring as in a lizard,
as in any ancient creature.
Ancient, ancient wiring at the base of the brain.
And what does that region do?
All the regulatory stuff.
Your body temperature changes,
it senses it and causes you to sweat or shiver.
It's monitoring your blood glucose levels
that's releasing hormones
that are essential to sort of every day shop keeping.
It's just keeping regulatory stuff in balance.
Sitting on top of that is the limbic system,
the emotional part of the brain.
This is very much mammalian specialty.
They're off there in the grasslands
butting heads with somebody else with antlers
and it's your limbic system that's heavily involved
in having to do with fear, arousal,
anxiety, sexual longings, all those sorts of things.
Then sitting on the top is the layer three, the cortex.
Most recently evolved part of the brain.
It's the part of the brain that does impulse control,
long-term planning, emotional regulation.
It's the frontal cortex that whispers in your ear saying,
'Do you really, really wanna do that right now?"
Functionally, it's very easy to think of
this simplistic flow of commands.
Layer two, the limbic system
could make layer one, the reptilian brain activate.
When is that?
Your heart beats faster,
not because of a regulatory reptilian thing.
Ooh, you've been cut, something painful,
but an emotional state.
You're a wildebeest and there are some scary,
menacing wildebeest threatening you
and that emotional state causes your limbic system
to activate the reptilian brain and your heart beats faster.
And you have a stress response,
not because a regulatory change happened in your body,
but for an emotional reason.
Then it's very easy to think of layer on top,
this cortical area, commanding your second layer,
your limbic system to have an emotional response.
Rather than something emotional,
here's a threatening beast right in front of you.
You see a movie that's emotionally upsetting.
These are not real characters, they're pixels
and it's your cortex that's turning
that abstract cognitive state into an emotional response.
Likewise, your cortex,
layer three could influence events down in layer one.
A purely cognitive state.
Ooh, on the other side of the planet,
there are people undergoing some traumatic event
and I feel upset about it and your reptilian brain responds.
So it's very easy given that,
to think of a three talks to two talks to one
sort of scenario.
Just as readily though, one talks to two talks to three.
What's your reptilian brain talking to your cortex?
Remarkable finding, when we're hungry,
we make harsher moral judgments
about people's transgressions,
we're less charitable, we cheat more in economic games.
Our cortex assessing the effects of pro-sociality,
anti-sociality and part of what it's doing in deciding
how it feels about somebody else's plight is
if your stomach's gurgling, if you're hungry,
if you're in pain,
that affects very cortical judgment type areas.
Layer one, this ancient reptilian brain
that should have nothing to do with how your cortex works,
having tons to do with it.
Or layer two influencing layer three, your limbic system.
Your emotional state
influence your abstract cognitive processes.
What's the most obvious example of it?
When we're under stress,
we make stupid impulsive decisions
that seem brilliant at the time.
It's embedded in the biology of all of these layers.
This interaction between these layers
seems it's a very mechanical process,
potentially even an unconscious one.
How do we consciously have, say,
our cortex regulate an emotion, a limbic two layer?
Simple, think about the most arousing wonderful thing
that ever happened to you umpteen decades ago,
and your cortex is evoking a memory
that's got your limbic system humming along
in some excited state.
Or pull out the memories of some traumatic event
and your limbic system is responding.
A lot harder is the inverse,
you're sitting there and you suffer from high blood pressure
and either they can marinate you in antihypertensive drugs
for the rest of your life or an alternative approach,
a biofeedback approach.
The core of biofeedback is figuring out
what sort of conscious states you can evoke
that will affect your reptilian brain
in a direction that's good for your health.
Biofeedback approach is:
sit there and think about the happiest day of your life.
Think about being in an open field that's beautiful.
Think about your favorite vacation.
Think about think about,
and if it's the right thinking about
suddenly your heart slows down,
suddenly your blood pressure goes down.
And all you do then is learn how to get better and better
in some stressed hypertensive circumstance.
What conscious active thinking
can I mobilize here at this point that will cause changes
in how my big toes blood flow is working?
In a case like that,
that is very conscious regulation of more autonomic,
more ancient parts of your brain.
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