- [Narrator] The default mode network activates
when a person is introspective
and under normal circumstances becomes less active
when a person shifts their attention to the outside world.
But brain studies show that under the influence
of a psychedelic,
the default mode network is quieted,
while other regions of the brain
increase communication with each other.
A mathematical model captures a normal brain's activity.
In contrast, a brain under the influence
of psilocybin reveals a dramatic increase
in global communication.
Thousands of new connections form,
linking brain regions
that don't normally talk to each other.
- One analogy I've used for how psychedelics work
in the brain is this snow globe.
When you pick up a snow globe
you know the snow's settled at the bottom,
it's sort of fixed, and then you pick it up, shake it
and things jiggle around and there's randomness
and a kind of chaos if you want in the system.
- [Narrator] The user experiences this as an altered
and heightened sense of awareness,
but what causes this?
- Early in our functional brain imaging studies
of psychedelics, scientists were finding
that the default mode networks turning down
or turning off during this experiences
and that was a really good place to start.
But we began to then look one layer deeper.
Why was the default mode turning off?
- [Narrator] New research led neuroscientist Fred Barrett
to investigate a region of the brain called the claustrum.
- The claustrum is a really thin sheet
of gray matter in the brain
tucked deep within each of the hemispheres of the brain.
Recent animal models have shown
that it is incredibly highly connected
to just about every other region of the brain.
Understanding that the receptors targeted
by psychedelic drugs are also really densely expressed
in the claustrum,
we began to wonder whether the classroom may be
at the center of psychedelic effects.
- [Narrator] Fred believes the claustrum's central location
and shape suggests it regulates communication
between the departments
- When it's functioning normally
the claustrum is essentially acting like a switchboard.
It's trying to help other brain regions figure out
when to turn on and when to turn off.
But when we experience a psychedelic drug,
we believe that it's binding to specific receptors
in the claustrum
and somehow disrupting or disorganizing the claustrum.
It's almost as if the switchboard walks away.
What happens next is
that we seem to observe a radical change
in the way that brain regions talk to each other.
And it may be within this context
that we're experiencing learning
and a possible even rewiring
of the circuits that govern our behavior.
And it may be that it's that radical reorganization
that allows people to encounter new psychological insights
that they hadn't encountered before.
- [Narrator] Fred thinks the claustrum's sudden
abdication of control may help explain why rigid behavior
and thought patterns have a shot at resetting.
- It's almost like they've seen this like kind of grand menu
within their mind that they weren't aware of that
this greater number of possibilities that they can explore.
- It took a while to recover.
I was having headaches and muscle pains,
but it was the best headache I'd ever had in my life
because it told me that the psilocybin was working.
It was actually physically restructuring my brain,
something that I never imagined could happen before.
- It's like reprogramming
the operating system of a computer.
You're getting down to very basic code level
changes that can enduringly change someone going forward.