Okay. So, why do we sleep?
So an obvious thing is we need
to sleep in order to survive.
So that’s called the
And that we’re diurnal by nature, meaning
that we’re creatures of the day.
And that makes sense, right?
A lot of animals are like this,
is that they have better
vision during the day,
there are less predators during the
day and so we function during the day
and we go to bed at night.
So the restorative theory
is that sleep allows
the body to heal and repair
tissue to include --
including the brain,
allows it to reorganize,
consolidate, and store the
memories that we have.
Now, this theory is quite popular
because, again, it makes a lot of sense
because during the day
you’re quite active.
You’re spending energy, you’re using your
muscles, you have a lot of tissue damage.
At night time you
need to shut down,
let everything take
care of itself,
and all the interactions and
engagement that you had during the day
need to get consolidated
which is another reason
why a lot of times,
your dream involved concepts of
what’s happened to you that day.
So during the day, you got up, you went
to school and you heard your professor.
You talked to that cute girl
down by the coffee shop.
You went and had dinner with
some friends, you watched
a sporting event, and
then you went to sleep.
It’s not a coincidence at
night your dream involves,
you know, the girl that you met,
all of a sudden, you’re in a
sporting event, you’re the star.
You know, and so on.
So concepts and pieces of
what’s happened in your day
start to show in that movie that’s
playing in your mind, in your dreams,
and the hypothesis is
that the concepts and the
memories of the day being
consolidated and stored.
There’s also the growth theory, which is
during sleep the pituitary gland releases a
lot of the growth hormones and the levels
of the hormone released decline as we age.
Hormone release also helps
determine when we sleep.
So, that is influencing when we
sleep, but why we sleep might be
because of this distribution
of some of these hormones.
And so as we get older,
we tend to sleep less
and we tend to have lower levels of these
hormones, also, not a coincidence.
Okay. So dreaming occurs while in the REM
stage of sleep. I’ve mentioned that already.
Now, there’s a phenomenon
called REM rebound,
which is when you don’t have periods
of REM and your body finally gets REM,
you have an increase in the period, duration,
frequency, and content of that dream.
So, in English, what
am I talking about?
So a phenomenon is, certain
medications that you
take actually prevent you
from getting into REM.
We know that alcohol,
especially higher levels of alcohol,
prevents you from achieving REM sleep.
So, take this example.
You’re going away on vacation
and you’re at a resort,
and it’s an all-inclusive and you’re eating
and drinking and you’re enjoying yourself,
and you’re by the
pool all day drinking
margaritas and you’re
having drinks with dinner.
And you might have maybe more than you
normally would on a regular basis.
In a week-long all-inclusive,
you’ve had quite a bit to drink.
And you might not be actually
achieving your normal sleep,
you’re not getting all your REM,
and so your body remembers that.
And it has a sleep debt.
It’s saying, “Well, you owe me some REM.
I haven’t had REM in a week.”
And you get back home.
And the first few nights you get back
home, you sleep like unbelievably,
because you’re back in your home
bed, you’re not drinking anymore,
you’re out of the sun, but
you have this REM rebound.
You have these very
And the periods of REM will
be a little bit longer,
and you might have more
episodes of REM that night.
And so, you know, in
your normal dreams,
they show you playing football,
and in this REM rebound dream,
you’re playing football and
it’s a championship game.
It’s very loud,
it’s very intense.
You know, a lot of times it’s
almost frightful these dreams
because they’re so intense, and
that’s that rebound effect.
You’re also going to have
something called lucid dreaming,
is when the dreamer is aware
that they’re dreaming.
This is a cool phenomenon.
And this is I’m sure
happened to you before,
where you’re in a dream,
and in this dream,
you know, I don’t know,
you’re unusually strong
and you’re surrounded
by a bevy of beauties
and you’re driving a Ferrari and you’re beating
up the bad guy at same time and you’re
a bullet proof and nothing is killing
you and just things are phenomenal.
But in the dream, you’re kind
of aware that this isn’t true.
And so, as the dreamer,
you’re aware that this is definitely
not true, but the dream can continue,
and you’re aware of the
fact that you’re dreaming.
And a lot of times, those who are
well-versed in lucid dreaming can actually
shift and shape where the
dream is going to go.
And, again, you may have done
this before where you’re like,
“This is so good. I hope this doesn’t end.
I want more of this,”
and you almost urge
the dream to go on,
or you might almost get
bumped out of your dream
and you force your way
back into the dream.
This is called lucid dreaming.
So, why do we dream?
Freud had a theory.
So Freud says that the plotlines of
dreams or manifest content were symbolic
versions of underlying latent content,
or unconscious drives and wishes.
Again, this might make sense.
If your dream was to always
wanting to be a soccer star,
and you have dreams
all the time of you
playing in the World Cup and scoring the
winning goal and hoisting up that trophy,
that might be some underlying
unconscious drives and wishes for you.
You know, in your dreams
you might be having
sex with a model that you
adore and you have her
pictures up on your wall, and at night
time you’re having these dreams.
I think that unconscious
drive is quite clear.
There’s learning and
Dreaming helps improve
Okay. So it’s really important
that prior to, say, you writing
your MCAT exams, you actually
get as much sleep as you can.
And it’s unfortunate, because
what do we end up doing
in university or things
like writing the MCAT?
You pull all-nighters,
you cram, and you limit
the amount of sleep
that you’re getting.
It actually lowers your ability in
terms of how well you do on the test.
This has been shown experimentally
with rats in a maze
and that rats that aren’t allowed
to sleep perform much more poorly
as opposed to ones that are allowed to get
ample sleep, and hit REM they do very well.
So, before your exam, make sure you’re
getting tons and tons of sleep.
There’s also the activation-synthesis
theory, which dreams
are byproducts of brain
activation during REM.
Again, what’s happening
to you during the day?
And what have you acquired?
What sensory information
has come in,
you’ve perceived it, and now you’re
trying to store it and consolidate it?
So what’s going on
is during the day,
all that stuff needs to be compiled and
the dreaming actually allows that.
And some of that is
expressed during REM.