Okay. So what’s the best way to think about the
brain? It’s insanely complicated. Everything connects to everything. A gazillion little subregions. Amid all that complexity there’s a broadly
sort of simplifying way to sort of think about aspects of brain function when it comes to
behavior. And this was an idea put forth by this guy
Paul MacLean, a grand poohbah on the field, conceptually of thinking of the brain as coming
in three functional layers. The triune brain—and again this is highly
schematic—The brain really doesn’t come in three layers, but one could think of the
first most, the bottom most, the most ancient as being what’s often termed the “reptilian
brain,” where basically the parts in there, we’ve got the same wiring as in a lizard,
as in any ancient creature. It’s been there forever—ancient, ancient
wiring at the base of the brain, most inside. 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. It’s like releasing hormones that are essential
to sort of everyday shop keeping. It’s just keeping regulatory stuff in balance. Sitting on top of that is conceptually what
could be termed the limbic system, the emotional part of the brain. And this is very much a mammalian specialty. Lizards are not well known for their emotional
lives. Part of the brain having to do with fear,
arousal, anxieties, sexual longings, all those sorts of things – very mammalian. You’re off there in the grasslands butting
heads with somebody else with antlers, and its your limbic system that’s heavily involved
in that. Then sitting on the top is the layer three,
the cortex. The cortex, spanking new, most recently evolved
part of the brain. Everybody’s got a little bit of cortex but
it’s not until you get to primates that you’ve got tons, and then apes, and then
us. So functionally it’s very easy to think
of this simplistic flow of commands. Layer two, the limbic system, can make layer
one, the reptilian brain, activate. When is that? Your heart beats faster not because of a regulatory
reptilian thing—Oh, you’ve been caught in something painful but oh, an emotional
state. You’re a wildebeest and they’re some scary
menacing wildebeest threatening you and that emotional state causes your limbic system
to activate the reptilian brain and your heart beats faster. 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, layered
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. Something emotional. You see a movie that’s emotionally upsetting. See a movie. 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. You see something upsetting, you think about
mortality, “One of these days my heart is going to stop beating,” and your heart’s
going to beat faster. You’re not bleeding and hypotensive. You’re not in some—nothing in the reptilian
brain could make sense of this. A purely cognitive state: “Oh, 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 would be a case of that? 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 prosociality,
antisociality and altruism and its evolution. And part of what it’s doing in deciding
how it feels about somebody else’s plight is if your stomach is 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 influencing your abstract cognitive processes. What’s the most obvious example of it? When we’re under stress. When we’re in an emotionally aroused state. We make stupid impulsive decisions that seem
brilliant at the time. Affective emotional limbic layer two influencing
how your cortical cortex goes about its abstractions. It’s not that abstract. It’s embedded in the biology of all these
layers. So on a certain level this interaction between
these layers it seems this 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 think about—think cortically, or pull
out the memories of—some traumatic event and your limbic system is responding. How about reptilian level? Easy to make it get into an agitated state. Sit there and think about something incredibly
upsetting. Think about some memory that was truly disturbing. Think about mortality. Think about global warming. And your heart speeds up. Layer three in a very conscious way has mobilized
layer one. A lot harder is the inverse: You’re sitting
there and you suffer from high blood pressure and either they could marinate you in antihypertensive
drugs for the rest of your life or an alternative approach, a 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. Ah, 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. And all you do then is learn how to get better
and better in some stressed hypertensive circumstance. What conscious act of thinking can I mobilize
here at this point that will cause changes in how my big toe’s blood flow is working? And a case like that, that is very conscious
regulation of more autonomic, more ancient parts of your brain.
