For thousands of years in cultures all across
the world, there has been a fascination with this tiny little structure in the back
of your brain called the pineal gland. The philosopher Rene Descartes even went
as far as to claim it as the "principal seat of the soul", which is about as
lofty of a claim as you can possibly get. In more modern times it's been associated
with the third eye chakra point. Some even speculate it might be the source
of the hormone responsible for dreaming and near-death experiences. Again, some pretty lofty claims. So in today's video we're going to
do a deep dive on the pineal gland. We're going to look at it, and
some of the surrounding anatomy. We're going to discuss its function
and see if there's any legitimacy to all the claims that have been made
over the past few thousand years. Let's do this! Let's start by taking a look at
some of the relevant anatomy so we can get a good understanding of the
exact location of the pineal gland. So first off, you're looking at a bisected head in the mid-sagittal plane — so that means
it's been cut right down the center. There is a ton of really interesting anatomy that
we can see here, but we're going to be focusing our attention today in this small portion in the
dead center of the head, called the diencephalon. There are several different structures
inside of the diencephalon, so once again we're going to try and limit
our focus to just a couple of areas, namely this region here that I'm traversing
with the probe, called the hypothalamus. It's called the hypothalamus because it's
just below this structure right here, called the thalamus. Then right behind the thalamus is
going to be this reddish—purple, tiny little structure, and this ladies
and gentlemen, is the pineal gland. Now the pineal gland is going to be reddish—purple because it is one of the most
vascular tissues in the body. In fact, it's a rebel! It's a renegade! Most of the structures you can see here are
going to have what's called the blood—brain barrier protecting it, which you could
think of as kind of like this bouncer, deciding what kind of substances get to
interact with the neurological tissue. But not the pineal gland! The pineal gland just has tons and tons and tons of blood flowing through it and that's
what gives it this darkened appearance. Another thing that's pretty
unique about this pineal gland is that there's really only one of it. What I mean by that is — if you take a look at all
the rest of these neurological structures in here, there is a left and a right hemisphere to them. So for instance, you're looking at the left
hemisphere of the cerebellum, and then behind this thick band of connective tissue, called the falx
cerebri, is the left hemisphere of the cerebrum. But not the pineal gland! There is only one pineal gland
— it doesn't have hemispheres. It's also going to be sitting
right dead in the center. Now this is the primary reason the philosopher
Rene Descartes decided — by the way, Rene Descartes is one of the most influential
people in all of philosophy — and he decided looking at this, he's like... "well if there's
two of everything else and only one of this, it makes a lot of sense that if anywhere in the brain
there was going to be the soul, this would be it!" The thing is, based on our current
understanding of neuroscience, there is no consciousness
located here in the pineal gland. It's glandular. This is going to secrete things like hormones
— not be a storehouse for consciousness. So, as cool of a thought as that is, I don't
think Rene Descartes was correct on that one. What about the whole "third eye" component to it? Because in my mind, this is actually super cool. Because the pineal gland, actually has
an indirect connection to your eyeballs. When light first hits your eyeballs,
it's going to go through these curved structures called the cornea and the lens,
and that's going to bend the light to hit this photoreceptive layer in the very
back of your eyeball, called the retina. The retina is then going to have
synapses and send the signals of that light to this area of the brain
right here called the hypothalamus. But it's a very specific
structure on the hypothalamus that I'm poking with my probe right
here, called the suprachiasmatic nucleus. This is your biological clock. You see, pretty much every living thing
on this planet — that includes plants, fungus, even you — has what's
known as a circadian rhythm. This is a perception of time, even at a cellular level, based around a
24-hour period as the earth turns around. This is so important to health, we're
just now realizing how big of an impact alterations in your circadian
rhythm can have in things such as schizophrenia, cancer, and all sorts of
very interesting neurological disorders. Your circadian rhythm is primarily
dictated by melatonin levels. Melatonin, which is probably familiar
to you because you can purchase this in a bottle at your local grocery
store, is a natural sleep aid. But it is what tells your cells and
your body to essentially just start quieting down — go to sleep. Guess where we know it's
produced at — the pineal gland. You see, the suprachiasmatic nucleus is going to
indirectly connect to the pineal gland, it's going to send some impulses to various other structures
down in the neck and then it's going to come back up and say, "hey! Pineal gland! Make more
melatonin when we're in the presence of darkness!" You see, it's not even
necessarily based around sunlight. It could be daytime, but you're in a pitch-black
room, what that will then tell your pineal gland through your suprachiasmatic nucleus is,
"hey, maybe it's time to go to sleep..." So what will happen, is in the lack of light, that is then going to stimulate
the pineal gland to create more melatonin. Again this is something we know for a
fact that the pineal gland is going to do. Maybe it's time we get into speculation
land, or conjecture land, or maybe land... And I don't say that because this is not true, it's just that we need a lot more evidence
before we can say it's definitely true. I'm mainly talking about the secretion and
creation of DMT, or dimethyltryptamine. Now this is a very psychoactive compound
that a lot of people think the pineal gland is going to secrete during things like
dreams and near-death experiences. The thing is as far as I know, we have
next to no evidence of that at all. As far as I can tell, that's just
something people are saying because it would make sense if that was the
case based on what we know about DMT. But that doesn't mean that we've actually
seen that in any kind of laboratory setting. In fact, we have only found
very minimal amounts of DMT in the brain of humans, and we have
found some in rodents like rats, but that doesn't necessarily mean that it
scales correctly or appropriately to humans. Just because it works in a mammal such as a rat, does not mean it's going to work the
same way in a mammal like a human. And the small amounts of DMT
that have been found in humans haven't been enough to be psychoactive... So basically if you're telling me that the
pineal gland is going to definitely secrete a whole bunch of DMT during near-death experiences,
I really don't know what you're basing that on... To me, that's nothing but conjecture. But again, I'm not saying that it's not true... In fact, based on what I know about DMT, I would
not be surprised at all if that is actually true. But at this point, we got to stop
saying it as though it's factual. I mean, you could get on the internet
right now — you get on YouTube right now and just find video after video
after video of people saying, "near-death experiences, dreams,
all this stuff is caused by DMT!" And I'm just like, "well... I
don't know how you know that..." So what does it all mean? Am I saying that it's all just
a bunch of hogwash and hooey? That there's no third-eye
component to it, and that DMT isn't being secreted from it and all that? Kind of! I'm not trying to be rude or offensive for any of you who may be really into this
opening up at the third-eye type stuff. Because I personally find that to be fascinating
to discuss and have conversations around. So I'm not trying to be rude or
offensive, but what I do want you to know, if there's one thing you take
away from this entire video, it's that all the stuff you're hearing in pop culture and
metaphysical realms is really just conjecture. It's just people saying stuff... And that's fine, again, as long as we're just
having interesting conversations about it. But as far as I can tell none of that
is actually grounded in science.
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This is a great anatomical analysis of the function of the pineal gland. Dives into the "proposed" secretion of DMT from the gland and other assumptions/ideas around its function. Worth watching!