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PROFESSOR: We had
finished talking

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about the pituitary organ and
what's being secreted there.

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Looked at it for a
rodent and for a human.

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And I just got up to this
question, number six there.

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00:00:43,070 --> 00:00:47,060
What homeostatic
mechanisms are associated

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with the hypothalamus?

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So what do we mean by
homeostatic mechanisms?

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00:00:53,725 --> 00:00:54,225
Anybody?

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00:00:57,370 --> 00:01:00,440
Usually we're talking
about internal environment

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00:01:00,440 --> 00:01:05,760
and maintaining something
in a homeostatic fashion.

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It means "same state."

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But, of course, do we
really mean "same state"?

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It would be almost
impossible to maintain it,

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like glucose
levels, for example.

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00:01:20,220 --> 00:01:25,440
So instead, our bodies maintain
levels of various things,

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00:01:25,440 --> 00:01:32,060
including temperature, glucose
levels, various minerals

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00:01:32,060 --> 00:01:35,160
in our blood, and so
forth, in a certain range.

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And if it gets outside the
range, then what happens?

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00:01:39,690 --> 00:01:43,200
If it's temperature,
we can think

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00:01:43,200 --> 00:01:47,570
of things that
happen automatically

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00:01:47,570 --> 00:01:52,050
to raise temperature or to
lower temperature, if our core

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00:01:52,050 --> 00:01:55,730
temperature gets too
far from that set range.

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00:01:55,730 --> 00:02:00,100
And as we know, in endothermic
animals like ourselves,

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00:02:00,100 --> 00:02:02,800
that range is fairly small.

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00:02:02,800 --> 00:02:03,300
OK.

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00:02:03,300 --> 00:02:05,830
And why do you think that is?

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00:02:05,830 --> 00:02:08,520
Well, various
biochemical processes

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00:02:08,520 --> 00:02:10,080
work best in a certain range.

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00:02:10,080 --> 00:02:15,060
And the brain functions
best in a certain range.

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00:02:15,060 --> 00:02:18,245
That's why the
poikilothermic animals--

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00:02:18,245 --> 00:02:22,930
the exothermic animals that
don't maintain their body

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00:02:22,930 --> 00:02:28,625
temperatures in such a
narrow range-- the reptiles,

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00:02:28,625 --> 00:02:31,690
the amphibians-- they
don't function well

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00:02:31,690 --> 00:02:32,850
when it gets cool.

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00:02:32,850 --> 00:02:36,720
And it's not that they
totally-- reptiles,

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00:02:36,720 --> 00:02:42,630
in particular, will basically
seek a quiet place where

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00:02:42,630 --> 00:02:47,370
they can rest if it's too
cool, and they do their hunting

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00:02:47,370 --> 00:02:48,970
after they've warmed up.

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00:02:48,970 --> 00:02:51,920
Like the iguana, they
will go out on rocks,

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00:02:51,920 --> 00:02:55,680
warm up quite a bit, go up into
the upper range of temperatures

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00:02:55,680 --> 00:02:57,490
that their body can tolerate.

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00:02:57,490 --> 00:03:00,840
And then they go into the water.

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00:03:00,840 --> 00:03:04,710
And the bigger ones can stay in
longer than the smaller ones,

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00:03:04,710 --> 00:03:09,660
because they don't lose body
temperature quite as fast.

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00:03:09,660 --> 00:03:14,300
But then what do we do if--
what happens to our bodies

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00:03:14,300 --> 00:03:16,642
if we get too cold?

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00:03:16,642 --> 00:03:18,400
Well, it-- sorry?

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00:03:18,400 --> 00:03:20,230
AUDIENCE: Piloerection.

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00:03:20,230 --> 00:03:22,650
PROFESSOR: Piloerection
for most mammals.

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00:03:22,650 --> 00:03:26,840
It doesn't help much with us,
but we still have that reflex.

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00:03:29,830 --> 00:03:31,550
What else?

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00:03:31,550 --> 00:03:35,147
Shivering, because
that generates heat

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from our muscles.

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00:03:38,860 --> 00:03:40,600
But we do a lot more.

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Our behavior changes.

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We go inside.

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We put on clothes.

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00:03:44,150 --> 00:03:46,840
We put on a coat, and
so on and so forth.

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Well, animals do it also.

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They may not have
clothes, but they've

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got usually better protection.

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But they seek warmer places.

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I think rodents have a nice
solution, the ones that

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live underground, because
you go very far underground

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and the temperature is
the same all the time.

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Now, we can say we maintain our
blood glucose homeostatically,

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00:04:21,019 --> 00:04:22,475
but we don't.

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00:04:22,475 --> 00:04:24,270
I mean, a few people
do, but most of us

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don't eat all the time.

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Some people are always snacking.

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00:04:27,610 --> 00:04:31,950
But normally we're just
eating at certain mealtimes,

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because our body has
various mechanisms

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for maintaining blood glucose.

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And, of course, we
need various nutrients

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that we don't have to
constantly take in.

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Some of them we need
only every few days.

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But, anyway, that, of course,
involves a lot of behavior.

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So we mentioned
temperature regulation.

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I think we've already
defined all of this.

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But there's other
cyclic behaviors

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besides eating, OK--
feeding and drinking.

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00:05:20,910 --> 00:05:27,285
Animals that are predators have
cycles of predation and rest

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and eating.

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00:05:29,930 --> 00:05:34,670
And all animals have a cycle
of sleeping and waking.

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00:05:34,670 --> 00:05:36,450
There's a lot of
variation in it,

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and of course there's day-active
and night-active animals.

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00:05:40,740 --> 00:05:41,980
But they all have it.

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We know how it's-- we talked
about how it's regulated

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00:05:44,930 --> 00:05:52,780
through the visual entrainment
of the biological clock.

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00:06:03,420 --> 00:06:05,500
And then we have
episodic behaviors.

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00:06:05,500 --> 00:06:09,440
That simply means there's
not a regular cycle.

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00:06:09,440 --> 00:06:11,973
But they're still under the
control of the hypothalamus.

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They're still part of our
biological drive equipment

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00:06:19,750 --> 00:06:21,770
that centers on
the hypothalamus,

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00:06:21,770 --> 00:06:24,190
but involves a lot
of other structures

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that are connected
with the hypothalamus.

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00:06:26,630 --> 00:06:28,080
The agonistic behaviors.

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That means fighting and
fleeing, or defending.

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00:06:31,670 --> 00:06:34,930
Reproductive behaviors.

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00:06:34,930 --> 00:06:37,030
And that includes
sexual behaviors

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00:06:37,030 --> 00:06:38,330
and parental behaviors.

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00:06:44,730 --> 00:06:50,380
And we know that associated with
these drives and the actions

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00:06:50,380 --> 00:06:54,040
that result are
various emotions.

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00:06:58,020 --> 00:07:02,700
So if the hypothalamus is
stimulated in some way,

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00:07:02,700 --> 00:07:04,750
you don't just
affect these drives.

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00:07:04,750 --> 00:07:08,740
You affect what we
call "feeling"--

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00:07:08,740 --> 00:07:12,690
technically, they're
called "affects"--

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00:07:12,690 --> 00:07:16,360
and the emotional displays,
the actual actions.

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00:07:16,360 --> 00:07:18,260
How do we show emotion?

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00:07:18,260 --> 00:07:20,500
Mainly through
facial expression.

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00:07:20,500 --> 00:07:23,550
What's its purpose?

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00:07:23,550 --> 00:07:24,880
We can-- it's communicative.

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It's a social behavior.

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00:07:27,370 --> 00:07:32,600
Other members of our species--
our mate, our friends--

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00:07:32,600 --> 00:07:35,711
know what we're going through.

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00:07:35,711 --> 00:07:36,210
All right.

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00:07:36,210 --> 00:07:40,750
And in this diagram of
the locomotor system,

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00:07:40,750 --> 00:07:47,880
which we saw earlier, this is
how the hypothalamus was simply

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00:07:47,880 --> 00:07:53,430
depicted as part of a hierarchy
of control of the action

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00:07:53,430 --> 00:07:56,730
pattern we just-- in other
words, it was a motor system.

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00:07:56,730 --> 00:08:01,130
And at the top level,
we have the drives.

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00:08:01,130 --> 00:08:03,340
And locomotion is
connected with most

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00:08:03,340 --> 00:08:09,580
of these motivational states
that we are talking about.

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00:08:09,580 --> 00:08:14,880
And because of
that, the activity

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00:08:14,880 --> 00:08:18,660
of hypothalamic systems,
we know that these things

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00:08:18,660 --> 00:08:22,530
are generated, not just from
the external environment,

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00:08:22,530 --> 00:08:28,270
but from changed level
of motivation controlled

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00:08:28,270 --> 00:08:29,970
by our brain.

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It's called endogenous control.

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00:08:35,520 --> 00:08:38,780
But the hypothalamus
doesn't act by itself.

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There's many inputs to it.

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00:08:40,120 --> 00:08:42,460
I'm just showing some
descending inputs

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00:08:42,460 --> 00:08:48,230
here, from the olfactory system
through the striatum-- other

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00:08:48,230 --> 00:08:52,220
systems, through the
thalamus-- the older thalamus--

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00:08:52,220 --> 00:08:55,520
and there we see
[? the newer ?] thalamus.

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00:08:55,520 --> 00:09:00,950
So that's the general
picture that you--

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00:09:00,950 --> 00:09:04,630
it's useful to know
this kind of thing

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00:09:04,630 --> 00:09:06,650
when you're thinking
of motor control.

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00:09:06,650 --> 00:09:09,270
But now it plays a
major role in thinking

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00:09:09,270 --> 00:09:11,030
about how the
hypothalamus works,

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00:09:11,030 --> 00:09:12,560
because it's so
critical to this.

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00:09:18,750 --> 00:09:20,810
We've talked, I
think, already about

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00:09:20,810 --> 00:09:24,300
appetitive and consummatory
behavior involved

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00:09:24,300 --> 00:09:28,450
in all of these
motivational states.

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00:09:28,450 --> 00:09:30,820
I discussed that a lot in
the animal behavior class.

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00:09:30,820 --> 00:09:34,010
But we've brought it up here.

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00:09:34,010 --> 00:09:35,635
You should be able
to distinguish them.

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00:09:39,100 --> 00:09:41,110
What you may not know,
and I do discuss it

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00:09:41,110 --> 00:09:46,710
in the chapter a little bit,
is the way if you disconnect

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00:09:46,710 --> 00:09:52,560
hypothalamus from the brain
stem, but not completely,

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00:09:52,560 --> 00:09:55,200
so these drives are
still affecting behavior,

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00:09:55,200 --> 00:10:00,490
but you can mess up the way
these consummatory behaviors--

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00:10:00,490 --> 00:10:02,570
these actions-- are expressed.

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00:10:02,570 --> 00:10:04,850
Many of them are complex.

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00:10:04,850 --> 00:10:10,660
So for example, in the
cat feeding behavior,

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00:10:10,660 --> 00:10:15,112
the cat doesn't just eat--
a cat in the wild-- I mean,

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00:10:15,112 --> 00:10:17,110
he has to catch prey.

165
00:10:17,110 --> 00:10:20,590
He has to take the prey to
where it's safe to eat it.

166
00:10:20,590 --> 00:10:22,910
Some of them take
the prey up a tree.

167
00:10:22,910 --> 00:10:26,200
They usually drag them away from
the site where they killed it.

168
00:10:28,920 --> 00:10:32,820
If you've got a pet and
the pet is just fed,

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00:10:32,820 --> 00:10:36,740
what happens to
all that behavior?

170
00:10:36,740 --> 00:10:39,090
Well, he normally suppresses it.

171
00:10:39,090 --> 00:10:42,180
But if you disconnect,
at least partially,

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00:10:42,180 --> 00:10:46,120
you partially disconnect
the hypothalamus

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00:10:46,120 --> 00:10:48,470
from those downstream
mechanisms--

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00:10:48,470 --> 00:10:50,580
separate the hypothalamus
from the midbrain,

175
00:10:50,580 --> 00:10:54,080
but only partially-- you can
get really bizarre patterns.

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00:10:54,080 --> 00:10:59,390
You can get cats-- they're pet
cats, or at least tame cats.

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00:10:59,390 --> 00:11:01,810
They may be laboratory
cats, but they're

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00:11:01,810 --> 00:11:03,900
taken care of pretty
much like pets.

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00:11:03,900 --> 00:11:06,770
They interact with humans a lot.

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00:11:06,770 --> 00:11:08,630
They can totally
change their behavior.

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00:11:08,630 --> 00:11:11,820
They can start treating
every bit of food

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00:11:11,820 --> 00:11:13,895
like they had to kill it.

183
00:11:13,895 --> 00:11:20,470
And they'll pounce on it,
execute a killing bite.

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00:11:20,470 --> 00:11:22,950
If they see water, they'll
show fishing behavior.

185
00:11:22,950 --> 00:11:25,700
Well, we don't even see
that much in pet cats,

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00:11:25,700 --> 00:11:29,530
unless you have
goldfish at home,

187
00:11:29,530 --> 00:11:35,500
and occasionally that innate
behavior of cats will appear.

188
00:11:35,500 --> 00:11:37,450
But after these
types of lesions,

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00:11:37,450 --> 00:11:39,300
you get bizarre combinations.

190
00:11:39,300 --> 00:11:41,960
And you also get some
that are just missing.

191
00:11:41,960 --> 00:11:45,520
You know, things
they just leave out,

192
00:11:45,520 --> 00:11:52,690
because the hypothalamus
affects the probability

193
00:11:52,690 --> 00:11:56,870
of all these different behaviors
connected with the drive, OK.

194
00:11:56,870 --> 00:11:59,390
And if you're disconnecting
different aspects

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00:11:59,390 --> 00:12:03,240
of those circuits
underlying those behaviors,

196
00:12:03,240 --> 00:12:05,210
then you've altered
the probabilities.

197
00:12:05,210 --> 00:12:09,080
And so some of them you just
may not see very much at all.

198
00:12:09,080 --> 00:12:13,630
Some of them you see
much more than normal.

199
00:12:13,630 --> 00:12:14,440
OK.

200
00:12:14,440 --> 00:12:21,320
And this view of motivation
that I'm talking about,

201
00:12:21,320 --> 00:12:24,130
this hierarchy, the
ultraprobability of action

202
00:12:24,130 --> 00:12:26,950
and so forth, has
been simulated.

203
00:12:26,950 --> 00:12:35,700
And this an area called
computational neuroethology,

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00:12:35,700 --> 00:12:40,540
which is not a
computational area that's

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00:12:40,540 --> 00:12:43,560
pract-- you don't find much
of it in this department.

206
00:12:43,560 --> 00:12:45,450
But we did have it
here for a while,

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00:12:45,450 --> 00:12:49,330
because I had a student
that was working on it.

208
00:12:49,330 --> 00:12:53,650
She worked with me and
someone in the Media Lab

209
00:12:53,650 --> 00:12:55,490
who had these screen characters.

210
00:12:55,490 --> 00:12:58,260
Did I talk about the
screen characters before?

211
00:12:58,260 --> 00:12:59,990
I didn't.

212
00:12:59,990 --> 00:13:01,830
It's described a
little bit in the book

213
00:13:01,830 --> 00:13:05,340
and I think I have--
let me just go to that.

214
00:13:08,840 --> 00:13:13,734
I mention here some earlier work
in that area-- nice simulations

215
00:13:13,734 --> 00:13:19,670
of the cockroach, neural
control of feeding.

216
00:13:19,670 --> 00:13:22,630
Basically, Beer
had a little robot.

217
00:13:22,630 --> 00:13:24,410
But he had motivation in it.

218
00:13:24,410 --> 00:13:29,430
So it did have endogenous
initiation of behavior.

219
00:13:29,430 --> 00:13:33,170
And it would do searching
behavior, and so forth.

220
00:13:33,170 --> 00:13:36,910
And he had-- you have to
have distinct appetitive

221
00:13:36,910 --> 00:13:40,950
and consummatory components
if it is going to work.

222
00:13:40,950 --> 00:13:46,560
And that's what Bruce Blumberg,
who when he was a student here,

223
00:13:46,560 --> 00:13:49,670
working on a PhD
in the Media Lab--

224
00:13:49,670 --> 00:13:53,730
before my student got involved,
he came to my animal behavior

225
00:13:53,730 --> 00:13:55,380
class-- not the
undergraduate class.

226
00:13:55,380 --> 00:13:58,640
I was teaching a grad
class at that time.

227
00:13:58,640 --> 00:14:00,850
And we talked
extensively about how

228
00:14:00,850 --> 00:14:03,950
that system has to be
organized in the brain,

229
00:14:03,950 --> 00:14:06,680
because that's what he
wanted to try to understand.

230
00:14:06,680 --> 00:14:14,810
And then he wrote software to
simulate that kind of drive,

231
00:14:14,810 --> 00:14:18,830
and basically developed
all the background--

232
00:14:18,830 --> 00:14:21,560
we would say the spinal
and brain-stem levels

233
00:14:21,560 --> 00:14:25,360
of the control, using
a large computer

234
00:14:25,360 --> 00:14:27,950
to handle all that background.

235
00:14:27,950 --> 00:14:32,100
And then they could write
programs on their desktops--

236
00:14:32,100 --> 00:14:36,190
they had pretty
powerful desktops--

237
00:14:36,190 --> 00:14:37,690
to control the higher levels.

238
00:14:37,690 --> 00:14:43,130
And they simulated
simple learning,

239
00:14:43,130 --> 00:14:45,680
what we call reinforcement--
reward-based learning.

240
00:14:45,680 --> 00:14:49,580
And I talked about that
in the behavior class too.

241
00:14:49,580 --> 00:14:53,110
And then we had a student here
who took the same behavior

242
00:14:53,110 --> 00:14:57,630
class later, Song-Yee
Yoon, who I show there.

243
00:14:57,630 --> 00:15:02,250
And she worked with
these, you could call them

244
00:15:02,250 --> 00:15:04,580
affective, synthetic characters.

245
00:15:04,580 --> 00:15:06,440
They were screen
characters that looked

246
00:15:06,440 --> 00:15:10,090
like cartoons on the
screen as you see here.

247
00:15:10,090 --> 00:15:13,200
But in fact, they were robots.

248
00:15:13,200 --> 00:15:17,080
They weren't programmed
ahead of time.

249
00:15:17,080 --> 00:15:19,660
What they were going to
do, what was programmed,

250
00:15:19,660 --> 00:15:25,130
was their drives, their sensory
systems, their motor systems.

251
00:15:25,130 --> 00:15:26,780
Of course, they were
very simplified,

252
00:15:26,780 --> 00:15:28,560
compared to real animals.

253
00:15:28,560 --> 00:15:31,130
But the amazing part
of her simulations

254
00:15:31,130 --> 00:15:35,350
was how human-like they
behaved, even though they

255
00:15:35,350 --> 00:15:38,100
had no cognition,
no higher cognition.

256
00:15:38,100 --> 00:15:42,980
They had something like a
striatum, connected only

257
00:15:42,980 --> 00:15:45,170
to vision and audition.

258
00:15:45,170 --> 00:15:48,770
That was the two kind of inputs
that you could give them.

259
00:15:48,770 --> 00:15:51,320
The visual input came
from other things

260
00:15:51,320 --> 00:15:54,650
on the screen, part
of that environment

261
00:15:54,650 --> 00:15:57,470
that the big computer
was controlling.

262
00:15:57,470 --> 00:15:59,000
And they responded
to us, and they

263
00:15:59,000 --> 00:16:01,231
responded to the
other characters.

264
00:16:01,231 --> 00:16:01,730
OK.

265
00:16:01,730 --> 00:16:02,230
Yes?

266
00:16:02,230 --> 00:16:07,050
AUDIENCE: So they don't
make [INAUDIBLE], right?

267
00:16:07,050 --> 00:16:08,170
PROFESSOR: Oh, they do.

268
00:16:08,170 --> 00:16:12,230
They [INAUDIBLE]
because the probability

269
00:16:12,230 --> 00:16:15,000
of various types of
behavior is controlled,

270
00:16:15,000 --> 00:16:16,530
remember, by the hypothalamus.

271
00:16:16,530 --> 00:16:18,610
And they had simulated that.

272
00:16:18,610 --> 00:16:20,840
And they had to have these
different drives inhibit

273
00:16:20,840 --> 00:16:22,290
each other and so forth.

274
00:16:22,290 --> 00:16:25,229
All of that we talked
about in behavior class.

275
00:16:25,229 --> 00:16:26,770
And, of course, I
pointed out to them

276
00:16:26,770 --> 00:16:28,290
that we don't know
all the details.

277
00:16:28,290 --> 00:16:30,460
I can't tell you
everything to simulate.

278
00:16:30,460 --> 00:16:33,460
You have to try it out.

279
00:16:33,460 --> 00:16:35,740
So what Song-Yee did
was quite amazing.

280
00:16:35,740 --> 00:16:37,930
She could program
these characters

281
00:16:37,930 --> 00:16:39,890
and give them
different personalities

282
00:16:39,890 --> 00:16:44,180
by the way she set the
parameters of the software.

283
00:16:44,180 --> 00:16:49,950
And she did an experiment
where she had students at MIT

284
00:16:49,950 --> 00:16:52,150
watch this for a while.

285
00:16:52,150 --> 00:16:54,600
She couldn't even predict
what was going to happen.

286
00:16:54,600 --> 00:16:57,230
But she would start
the simulation.

287
00:16:57,230 --> 00:16:59,490
The students would interact
with the characters.

288
00:16:59,490 --> 00:17:02,000
They could put stimuli in there.

289
00:17:02,000 --> 00:17:05,384
You know, they did allow
the people on the outside

290
00:17:05,384 --> 00:17:07,599
to control and
that you could even

291
00:17:07,599 --> 00:17:09,050
say certain things and so forth.

292
00:17:09,050 --> 00:17:11,220
I don't remember
all the details.

293
00:17:11,220 --> 00:17:14,930
But, anyway, she had them
rate the personalities.

294
00:17:14,930 --> 00:17:17,380
She basically gave
them a checklist

295
00:17:17,380 --> 00:17:20,160
and had them rate each
of these three characters

296
00:17:20,160 --> 00:17:23,420
according to their
personality, because we

297
00:17:23,420 --> 00:17:27,790
were trying to see,
you know, how realistic

298
00:17:27,790 --> 00:17:31,030
was it to say we could
control personality just

299
00:17:31,030 --> 00:17:34,890
by these parameters in
the motivational system.

300
00:17:34,890 --> 00:17:38,515
But the students made it--
it was very consistent,

301
00:17:38,515 --> 00:17:42,150
her results-- way,
way above chance.

302
00:17:42,150 --> 00:17:46,800
They could consistently
classify the personalities

303
00:17:46,800 --> 00:17:49,490
of these simulated
characters, just

304
00:17:49,490 --> 00:17:53,480
by controlling these
types of circuits

305
00:17:53,480 --> 00:17:55,010
that they were simulating.

306
00:17:55,010 --> 00:17:56,761
OK.

307
00:17:56,761 --> 00:17:57,260
Anyway--

308
00:18:00,474 --> 00:18:02,940
AUDIENCE: Can we find this
information somewhere?

309
00:18:02,940 --> 00:18:05,280
PROFESSOR: We can ask
Song-Yee about it.

310
00:18:05,280 --> 00:18:07,605
I just talked to her last week.

311
00:18:07,605 --> 00:18:09,440
I keep in touch with her a bit.

312
00:18:12,460 --> 00:18:14,380
She didn't stay in academia.

313
00:18:14,380 --> 00:18:18,260
She went into business,
into the business world.

314
00:18:18,260 --> 00:18:22,110
And she went to work for SK
Telecommunications Company.

315
00:18:22,110 --> 00:18:24,050
I think I told you
about that last time.

316
00:18:24,050 --> 00:18:27,160
And she developed-- she
used that kind of software

317
00:18:27,160 --> 00:18:30,980
there to create these little
avatars on their phones,

318
00:18:30,980 --> 00:18:33,770
so people could
interact with them.

319
00:18:33,770 --> 00:18:40,460
She was so early, that
it was very popular.

320
00:18:40,460 --> 00:18:43,370
But other companies,
then, of course all

321
00:18:43,370 --> 00:18:47,530
copied it-- AT&T, the
Japanese, and so forth.

322
00:18:47,530 --> 00:18:50,850
And they quickly
made business deals

323
00:18:50,850 --> 00:18:54,990
with all the Japanese companies,
the American companies,

324
00:18:54,990 --> 00:18:58,280
and basically they got sort
of beat out a little bit

325
00:18:58,280 --> 00:18:59,515
by being so early.

326
00:19:02,440 --> 00:19:06,090
And so she learned from that.

327
00:19:06,090 --> 00:19:11,670
And now she's working
with her husband who

328
00:19:11,670 --> 00:19:14,550
formed this big
online gaming company.

329
00:19:14,550 --> 00:19:17,140
He was the guy who started
the online gaming where

330
00:19:17,140 --> 00:19:19,840
thousands of people
play it at once.

331
00:19:19,840 --> 00:19:23,080
And she lives in
the Seattle area.

332
00:19:23,080 --> 00:19:24,740
She has a couple of kids.

333
00:19:24,740 --> 00:19:27,600
But she heads up the
North American operation,

334
00:19:27,600 --> 00:19:31,340
and her husband heads
the worldwide operation.

335
00:19:31,340 --> 00:19:36,750
But they are now-- more and
more of this kind of software

336
00:19:36,750 --> 00:19:41,580
that we were just talking about
is going into those games.

337
00:19:41,580 --> 00:19:46,820
So I think it will
be exciting to see,

338
00:19:46,820 --> 00:19:52,840
because they don't yet have
a higher level cognition.

339
00:19:52,840 --> 00:19:56,340
I told her-- I gave here a copy
my book-- because, of course,

340
00:19:56,340 --> 00:19:58,260
I didn't put these
figures in the book,

341
00:19:58,260 --> 00:20:00,060
but I do describe
it a little bit.

342
00:20:00,060 --> 00:20:04,660
And I suggested to her
something that people haven't

343
00:20:04,660 --> 00:20:06,670
gone very far with
simulation-- and that's

344
00:20:06,670 --> 00:20:10,400
the hippocampal type of
learning in there also.

345
00:20:10,400 --> 00:20:15,550
And that will be a major step
if people can simulate that.

346
00:20:15,550 --> 00:20:19,820
People have tried to simulate
the hippocampus, but never

347
00:20:19,820 --> 00:20:22,240
in screen characters
like this, where

348
00:20:22,240 --> 00:20:25,430
you have actual behavior
being controlled.

349
00:20:25,430 --> 00:20:31,597
So that will be exciting
to see if they can do that.

350
00:20:31,597 --> 00:20:32,472
AUDIENCE: [INAUDIBLE]

351
00:20:35,820 --> 00:20:38,100
PROFESSOR: Yeah,
I think I actually

352
00:20:38,100 --> 00:20:39,860
used to show it in the class.

353
00:20:39,860 --> 00:20:42,280
I need to see if I can find it.

354
00:20:42,280 --> 00:20:43,710
I don't remember now.

355
00:20:43,710 --> 00:20:47,350
I remember I was teaching
901 at that time,

356
00:20:47,350 --> 00:20:51,170
was the last-- I
taught 901 until 2003.

357
00:20:51,170 --> 00:20:53,554
And she graduated in 2000.

358
00:20:53,554 --> 00:20:55,410
AUDIENCE: Did you
know [INAUDIBLE]?

359
00:20:55,410 --> 00:20:58,440
PROFESSOR: So I had those few
years where I was actually

360
00:20:58,440 --> 00:20:59,622
showing something in class.

361
00:20:59,622 --> 00:21:01,330
And I don't remember
what happened to it.

362
00:21:01,330 --> 00:21:04,439
She probably has
some copies of it.

363
00:21:04,439 --> 00:21:06,480
I think it would be fun
if I can get it from her.

364
00:21:06,480 --> 00:21:08,080
We could take a look.

365
00:21:12,450 --> 00:21:14,780
Maybe in my older
versions of 901

366
00:21:14,780 --> 00:21:18,660
I had actually--
I don't know what,

367
00:21:18,660 --> 00:21:22,605
if I transferred it all
to my newer computers.

368
00:21:22,605 --> 00:21:23,480
It's a good question.

369
00:21:23,480 --> 00:21:24,275
I should look.

370
00:21:28,641 --> 00:21:29,140
OK.

371
00:21:29,140 --> 00:21:33,810
I wanted to say a little bit
about feeding and hunger.

372
00:21:33,810 --> 00:21:36,420
Where would you expect
hunger and satiety cues

373
00:21:36,420 --> 00:21:38,730
to influence the CNS?

374
00:21:38,730 --> 00:21:42,150
Well, the obvious answer by
now should be hypothalamus.

375
00:21:42,150 --> 00:21:44,240
It should get there in some way.

376
00:21:44,240 --> 00:21:45,940
But where do the
queues come from?

377
00:21:49,740 --> 00:21:54,560
We already mentioned the brain
can detect glucose levels.

378
00:21:54,560 --> 00:21:57,470
There are glucoreceptors
in the hypothalamus.

379
00:21:57,470 --> 00:21:59,330
OK.

380
00:21:59,330 --> 00:22:02,380
You can link something
to glucose molecules

381
00:22:02,380 --> 00:22:04,520
and find it in the brain.

382
00:22:04,520 --> 00:22:07,470
It will collect in
the hypothalamus.

383
00:22:07,470 --> 00:22:11,820
One of the early methods was to
link gold-- gold thioglucose--

384
00:22:11,820 --> 00:22:16,560
OK, link gold through a sulfur
molecule to the glucose.

385
00:22:16,560 --> 00:22:19,810
And it will collect in
the brain and stay there

386
00:22:19,810 --> 00:22:21,600
and kill the cells.

387
00:22:21,600 --> 00:22:26,180
So you basically can
cause behavioral change

388
00:22:26,180 --> 00:22:30,660
by this chemical means.

389
00:22:30,660 --> 00:22:36,260
But there's much better
ways to do that now.

390
00:22:36,260 --> 00:22:43,090
But, of course, we get
many cues through pathways,

391
00:22:43,090 --> 00:22:45,045
through the visceral
sensory system.

392
00:22:45,045 --> 00:22:45,905
OK.

393
00:22:45,905 --> 00:22:49,320
It comes by way of
the vagus nerve.

394
00:22:49,320 --> 00:22:54,500
For example, signals of
stomach distention, which

395
00:22:54,500 --> 00:22:59,090
in infants-- newborns-- it's
the only thing they have.

396
00:22:59,090 --> 00:23:02,740
They cry if their stomach's
not distended with milk.

397
00:23:02,740 --> 00:23:06,485
And when it is,
they stop crying.

398
00:23:06,485 --> 00:23:08,660
They're satisfied.

399
00:23:08,660 --> 00:23:11,120
That, of course,
develops over time

400
00:23:11,120 --> 00:23:14,670
into a much more sophisticated
system for controlling hunger

401
00:23:14,670 --> 00:23:15,280
and satiety.

402
00:23:23,150 --> 00:23:26,930
If you don't have-- if the
midbrain is the highest

403
00:23:26,930 --> 00:23:29,990
level, which is almost
true of the newborn,

404
00:23:29,990 --> 00:23:35,880
but if you get animals that are
anencephalic because they're

405
00:23:35,880 --> 00:23:39,960
born with, where the neural
tube hasn't completely closed.

406
00:23:39,960 --> 00:23:42,880
They don't live very
long, because they're

407
00:23:42,880 --> 00:23:46,210
born with-- you know,
the whole endbrain

408
00:23:46,210 --> 00:23:48,020
is not fully developed.

409
00:23:48,020 --> 00:23:50,510
The neural tube hasn't closed.

410
00:23:50,510 --> 00:23:54,820
So basically you're
dealing with a newborn

411
00:23:54,820 --> 00:23:58,230
that the midbrain is the
highest, really, functioning

412
00:23:58,230 --> 00:24:01,510
level of the nervous system.

413
00:24:01,510 --> 00:24:07,520
And they do show
reflex eating, but they

414
00:24:07,520 --> 00:24:11,620
don't show normal hunger
and satiety at all,

415
00:24:11,620 --> 00:24:16,420
in addition, of course, to
missing a lot of other things.

416
00:24:16,420 --> 00:24:17,670
So you get the reflexes.

417
00:24:17,670 --> 00:24:20,670
You get the consummatory
patterns, very little

418
00:24:20,670 --> 00:24:23,150
regulation.

419
00:24:23,150 --> 00:24:26,990
You can always get chewing,
licking, swallowing.

420
00:24:26,990 --> 00:24:30,330
But you get it whether they're
starved or full of food.

421
00:24:33,080 --> 00:24:34,640
No active seeking of food.

422
00:24:34,640 --> 00:24:38,600
Exactly what you
see in animals we

423
00:24:38,600 --> 00:24:44,960
talked about before-- animals
where you remove the entire--

424
00:24:44,960 --> 00:24:51,310
or you've disconnected
the cerebral hemispheres--

425
00:24:51,310 --> 00:24:53,630
including the hypothalamus.

426
00:24:53,630 --> 00:24:55,060
Remember, to keep
them alive, you

427
00:24:55,060 --> 00:24:57,930
have to leave the hypothalamus
attached to the pituitary

428
00:24:57,930 --> 00:25:00,900
to maintain blood
levels of hormones.

429
00:25:00,900 --> 00:25:01,400
OK.

430
00:25:01,400 --> 00:25:06,450
But you can disconnect that
area from the midbrain.

431
00:25:06,450 --> 00:25:08,330
Now we know that the
mid-- well, we'll

432
00:25:08,330 --> 00:25:12,000
see that here-- the
midbrain is capable of some

433
00:25:12,000 --> 00:25:12,950
of these same things.

434
00:25:12,950 --> 00:25:15,810
But it seems like
once it's disconnected

435
00:25:15,810 --> 00:25:21,440
from the hypothalamus,
it doesn't function well

436
00:25:21,440 --> 00:25:22,392
by itself.

437
00:25:22,392 --> 00:25:23,850
And I think that
would be different

438
00:25:23,850 --> 00:25:26,710
if you could wait long enough,
if you keep the animals alive

439
00:25:26,710 --> 00:25:28,010
a very long time.

440
00:25:28,010 --> 00:25:30,730
That's very difficult to do.

441
00:25:30,730 --> 00:25:32,330
So we think core
brain mechanisms

442
00:25:32,330 --> 00:25:35,730
are pretty critical for
normal motivation in all

443
00:25:35,730 --> 00:25:38,920
the motivational systems.

444
00:25:38,920 --> 00:25:42,670
So this is just what
we've been talking about.

445
00:25:42,670 --> 00:25:44,616
And I mentioned the
inputs to the vagus.

446
00:25:44,616 --> 00:25:45,865
I mentioned the blood factors.

447
00:25:48,850 --> 00:25:50,710
And I mentioned--
I separate here,

448
00:25:50,710 --> 00:25:54,556
short-term and
long-term regulation.

449
00:25:54,556 --> 00:26:05,150
You know, the blood factors
that indicate amount of fat,

450
00:26:05,150 --> 00:26:07,950
for example, control
the amount of eating.

451
00:26:07,950 --> 00:26:10,320
But that's a
long-term regulator.

452
00:26:10,320 --> 00:26:14,630
It doesn't change fast enough
to affect how long you eat.

453
00:26:14,630 --> 00:26:16,530
What affects that?

454
00:26:16,530 --> 00:26:20,010
Why do you just eat a
certain amount and stop.

455
00:26:20,010 --> 00:26:21,660
We're actually not like infants.

456
00:26:21,660 --> 00:26:23,660
We don't all eat
until our stomach

457
00:26:23,660 --> 00:26:27,360
is distended like the newborn.

458
00:26:27,360 --> 00:26:29,985
Some of us may
sometimes, especially

459
00:26:29,985 --> 00:26:32,170
at Thanksgiving, you know.

460
00:26:32,170 --> 00:26:33,990
But usually we don't.

461
00:26:33,990 --> 00:26:36,100
And it's the same for animals.

462
00:26:36,100 --> 00:26:41,560
This was an early experiment
of Pavlov and others,

463
00:26:41,560 --> 00:26:48,490
where they led the
esophagus out into a bag,

464
00:26:48,490 --> 00:26:50,550
so the food never
got to the stomach.

465
00:26:50,550 --> 00:26:55,000
And yet the dog would eat a
meal of a certain size and stop.

466
00:26:55,000 --> 00:26:57,330
It doesn't have to go to the
stomach and cause stomach

467
00:26:57,330 --> 00:26:59,520
distension, even though
there are signals

468
00:26:59,520 --> 00:27:05,620
from the stomach that will
stop eating because of pathways

469
00:27:05,620 --> 00:27:08,830
going to the hypothalamus.

470
00:27:08,830 --> 00:27:11,250
Yet they still stop,
just by signals

471
00:27:11,250 --> 00:27:12,740
coming from the
throat and mouth.

472
00:27:20,520 --> 00:27:27,480
Now, I mentioned electrically
stimulated aggression.

473
00:27:27,480 --> 00:27:29,780
You can stimulate
the hypothalamus

474
00:27:29,780 --> 00:27:33,090
and get an animal that
acts like he's hungry.

475
00:27:33,090 --> 00:27:37,980
So you can stimulate in a
predator lateral hypothalamus

476
00:27:37,980 --> 00:27:40,730
and find areas that he
goes into a predator mode

477
00:27:40,730 --> 00:27:42,870
when you stimulate it.

478
00:27:42,870 --> 00:27:44,790
So I'm saying what
recently developed

479
00:27:44,790 --> 00:27:47,810
technique is replacing the
use of electrical stimulation?

480
00:27:50,350 --> 00:27:53,350
Optogenetics, where
you can specifically

481
00:27:53,350 --> 00:27:57,020
stimulate particular cells.

482
00:27:57,020 --> 00:27:58,620
And sometimes you
can actually get

483
00:27:58,620 --> 00:28:03,570
them to link only to
cells of a given type.

484
00:28:03,570 --> 00:28:08,620
Or you can just put
the virus in that

485
00:28:08,620 --> 00:28:13,450
puts those opsins into
the cells and makes

486
00:28:13,450 --> 00:28:15,770
them sensitive to light.

487
00:28:15,770 --> 00:28:18,380
But that is now being
used to study hunger,

488
00:28:18,380 --> 00:28:21,720
so they're getting more
specific information, including

489
00:28:21,720 --> 00:28:25,070
information about
specific pathways,

490
00:28:25,070 --> 00:28:27,310
although that work
had gone pretty

491
00:28:27,310 --> 00:28:29,440
far without that technique.

492
00:28:29,440 --> 00:28:31,350
Now they can advance
it a lot more rapidly.

493
00:28:36,230 --> 00:28:41,450
Now if you stimulate
attack motivation in a cat,

494
00:28:41,450 --> 00:28:46,050
how do you know you didn't
just make him more hungry.

495
00:28:46,050 --> 00:28:48,940
We know the behavior
is different-- feeding

496
00:28:48,940 --> 00:28:54,040
and predator behavior of cats.

497
00:28:54,040 --> 00:28:56,430
But first of all,
it's important to know

498
00:28:56,430 --> 00:29:02,450
are you really stimulating
attack behavior?

499
00:29:02,450 --> 00:29:05,960
In fact, there's more than one
kind of attack behavior too.

500
00:29:05,960 --> 00:29:08,760
But let's just talk
about predatory attack.

501
00:29:08,760 --> 00:29:12,010
It's called biting
attack in the cat.

502
00:29:12,010 --> 00:29:16,400
Well you have to pit
things against each other.

503
00:29:16,400 --> 00:29:20,100
So the classic
experiment-- I call

504
00:29:20,100 --> 00:29:24,100
it classic because I
think it's so good.

505
00:29:24,100 --> 00:29:26,370
Maybe it's not classic
because not enough people

506
00:29:26,370 --> 00:29:27,030
know about it.

507
00:29:27,030 --> 00:29:29,810
But this was work done by John
Flynn and his group at Yale

508
00:29:29,810 --> 00:29:32,280
University, which
I know a lot about,

509
00:29:32,280 --> 00:29:35,070
because one of his students came
up to work with [? Naro ?] when

510
00:29:35,070 --> 00:29:39,370
I was working with
[? Naro. ?] That was Carl Chi.

511
00:29:39,370 --> 00:29:43,380
And he described to me
these experiments in detail.

512
00:29:43,380 --> 00:29:50,770
They would, for example, have
a cat in a room, have some mice

513
00:29:50,770 --> 00:29:53,640
or rats also in
the room-- usually

514
00:29:53,640 --> 00:29:55,600
at the other end of the room.

515
00:29:55,600 --> 00:29:57,300
They turn the stimulus on.

516
00:29:57,300 --> 00:29:58,960
This is a cat who was satiated.

517
00:29:58,960 --> 00:30:00,290
He had eaten.

518
00:30:00,290 --> 00:30:01,110
OK.

519
00:30:01,110 --> 00:30:04,250
And his ears would prick up.

520
00:30:04,250 --> 00:30:06,540
He would start looking around.

521
00:30:06,540 --> 00:30:10,150
And he would immediately then,
after the stimulus went on,

522
00:30:10,150 --> 00:30:12,840
he would attack
the mouse or rat.

523
00:30:12,840 --> 00:30:14,380
So then they did
experiments where

524
00:30:14,380 --> 00:30:18,220
they would put the
favorite food of the cat,

525
00:30:18,220 --> 00:30:21,760
like tuna fish or some
other fish-- cats love it.

526
00:30:21,760 --> 00:30:25,270
And they would leap
right over that,

527
00:30:25,270 --> 00:30:30,650
totally ignore it to get
at the mouse or the rat,

528
00:30:30,650 --> 00:30:32,230
indicating that
it was definitely

529
00:30:32,230 --> 00:30:34,500
not hunger they were triggering.

530
00:30:34,500 --> 00:30:39,210
They could make the animal
hungry with different sites.

531
00:30:39,210 --> 00:30:40,880
The problem with
that kind of work

532
00:30:40,880 --> 00:30:43,935
is that they're actually
stimulating many axons.

533
00:30:47,900 --> 00:30:49,950
But there's always
a dominant one,

534
00:30:49,950 --> 00:30:51,840
and that's the behavior you see.

535
00:30:51,840 --> 00:30:54,640
There's obviously a lot
of reciprocal inhibition

536
00:30:54,640 --> 00:30:59,610
of these motivational states,
so they affect each other.

537
00:30:59,610 --> 00:31:03,070
And if the animal is
hunting, he's not eating.

538
00:31:03,070 --> 00:31:04,150
OK.

539
00:31:04,150 --> 00:31:06,730
The eating is separate.

540
00:31:06,730 --> 00:31:11,450
This just shows a site where
they could get attack behavior.

541
00:31:11,450 --> 00:31:14,070
And after the
experiment was over,

542
00:31:14,070 --> 00:31:16,430
they would make a
little lesion there.

543
00:31:16,430 --> 00:31:20,805
Then they would let the animal
live for five, six days.

544
00:31:23,330 --> 00:31:26,590
They just let him live long
enough after the experiment was

545
00:31:26,590 --> 00:31:30,060
over so they could then
trace degenerating axons.

546
00:31:30,060 --> 00:31:32,660
You have to give them a
little time-- the axons time

547
00:31:32,660 --> 00:31:33,760
to degenerate.

548
00:31:33,760 --> 00:31:36,010
And then they would
trace-- that was

549
00:31:36,010 --> 00:31:38,240
one reason Chi came
to [? Naro's ?] lab,

550
00:31:38,240 --> 00:31:39,270
to learn how to do this.

551
00:31:39,270 --> 00:31:42,900
So this experiment was
done involving Carl Chi

552
00:31:42,900 --> 00:31:45,120
after he had worked
with [? Naro. ?]

553
00:31:45,120 --> 00:31:47,480
And you can see he
could trace axons

554
00:31:47,480 --> 00:31:49,210
to other parts of
the hypothalamus

555
00:31:49,210 --> 00:31:53,070
to almost the entire
subthalamic area at this level.

556
00:31:53,070 --> 00:31:56,990
This is the zona incerta of
the hypothalamus-- sorry,

557
00:31:56,990 --> 00:31:58,510
the subthalamus.

558
00:31:58,510 --> 00:32:01,980
And then this is the midline
and intralaminar nuclei

559
00:32:01,980 --> 00:32:04,900
of the thalamus--
the older structures

560
00:32:04,900 --> 00:32:08,240
of the thalamus--
first-to-evolve structures

561
00:32:08,240 --> 00:32:12,465
that connect to the striatum
and also to the pallium,

562
00:32:12,465 --> 00:32:16,670
OK, the cortex.

563
00:32:16,670 --> 00:32:19,400
And the interesting part
about these pathways

564
00:32:19,400 --> 00:32:23,820
is neurons in here
have connections

565
00:32:23,820 --> 00:32:25,620
to the [? neural ?]
parts of the thalamus.

566
00:32:25,620 --> 00:32:28,740
So they're affecting--
they're sort

567
00:32:28,740 --> 00:32:32,680
of dating information
going through the thalamus

568
00:32:32,680 --> 00:32:36,710
just by altering the
motivational level from down

569
00:32:36,710 --> 00:32:37,210
here.

570
00:32:40,480 --> 00:32:42,720
OK.

571
00:32:42,720 --> 00:32:45,520
I'm not going to go through
this "drive and reward involving

572
00:32:45,520 --> 00:32:46,590
distinct axons."

573
00:32:46,590 --> 00:32:49,160
Students always find it a
little difficult to understand.

574
00:32:49,160 --> 00:32:52,800
Read it in the book, and let
me know if you can follow it.

575
00:32:52,800 --> 00:32:56,190
I would like to know.

576
00:32:56,190 --> 00:33:00,990
Because I would at least like
to start what we originally

577
00:33:00,990 --> 00:33:07,470
scheduled for today-- the core
pathways of the limbic system.

578
00:33:07,470 --> 00:33:12,370
And that will lead us
to studies of memory.

579
00:33:12,370 --> 00:33:14,470
I want you to
begin to understand

580
00:33:14,470 --> 00:33:19,790
why the limbic system became
so critical to our memory

581
00:33:19,790 --> 00:33:22,615
formation, what we
call episodic memory.

582
00:33:26,870 --> 00:33:29,200
So these are the topics
we're going to talk about.

583
00:33:29,200 --> 00:33:32,235
Let's at least talk a little
bit about [? hypokalemic ?] cell

584
00:33:32,235 --> 00:33:33,925
groups before we quit.

585
00:33:33,925 --> 00:33:35,410
And I'll show you
the [? pages ?]

586
00:33:35,410 --> 00:33:38,707
where you will
read about it so we

587
00:33:38,707 --> 00:33:40,290
can go through the
rest of it quickly.

588
00:33:42,840 --> 00:33:45,790
Then we're going to talk a
little bit about hormones.

589
00:33:45,790 --> 00:33:49,140
I may decide to save time
and to let you just read

590
00:33:49,140 --> 00:33:51,640
that chapter on hormones.

591
00:33:51,640 --> 00:33:53,690
I can show you a
few slides from it,

592
00:33:53,690 --> 00:33:56,260
just so you'll have a chance
to ask about if you want to,

593
00:33:56,260 --> 00:33:57,970
because I want to
spend more time talking

594
00:33:57,970 --> 00:34:00,237
about the hippocampus,
which we do introduce today.

595
00:34:03,160 --> 00:34:06,220
So two divisions in
the hypothalamus.

596
00:34:06,220 --> 00:34:09,159
Two major divisions-- medial
division and lateral division.

597
00:34:09,159 --> 00:34:10,130
They're very different.

598
00:34:10,130 --> 00:34:12,310
They look different
histologically.

599
00:34:12,310 --> 00:34:17,825
If you look here at a
section of the rodent brain.

600
00:34:24,880 --> 00:34:30,590
Here you have from here to
here-- the medial division.

601
00:34:30,590 --> 00:34:32,929
And from here to out here,
the lateral division.

602
00:34:32,929 --> 00:34:35,805
So this is all lateral
in the hypothalamus.

603
00:34:35,805 --> 00:34:38,440
This is medial.

604
00:34:38,440 --> 00:34:40,940
Notice this very
distinct cell group

605
00:34:40,940 --> 00:34:44,400
in the medial hypothalamus--
the ventral medial nucleus

606
00:34:44,400 --> 00:34:47,010
of the hypothalamus, the VMH.

607
00:34:47,010 --> 00:34:50,570
That is typical of the
medial hypothalamus.

608
00:34:50,570 --> 00:34:54,860
This is from a study
by Le Gros Clark.

609
00:34:54,860 --> 00:34:56,854
He did this reconstruction.

610
00:34:56,854 --> 00:35:01,310
He used sections of the brain
to discern these various cell

611
00:35:01,310 --> 00:35:01,810
groups.

612
00:35:01,810 --> 00:35:05,050
And then he reconstructed
them, sort of projecting them

613
00:35:05,050 --> 00:35:09,860
onto the midsagittal plane.

614
00:35:09,860 --> 00:35:15,180
So you can see the mammillary
bodies, dorsal medial nucleus,

615
00:35:15,180 --> 00:35:20,030
ventral medial nucleus in
human, preoptic nucleus,

616
00:35:20,030 --> 00:35:21,850
supraoptic nucleus.

617
00:35:21,850 --> 00:35:26,460
There's the big optic
chiasm in human right there.

618
00:35:26,460 --> 00:35:29,190
And this little funnel shape.

619
00:35:29,190 --> 00:35:31,690
He's near the pituitary.

620
00:35:31,690 --> 00:35:36,630
So if you look here in a
rodent, it's the same thing,

621
00:35:36,630 --> 00:35:39,000
but the shape is very different.

622
00:35:39,000 --> 00:35:42,260
There's the chiasm up there,
with the supraoptic nucleus

623
00:35:42,260 --> 00:35:43,110
above it.

624
00:35:43,110 --> 00:35:47,550
Here's the pituitary attached
here-- the neural part

625
00:35:47,550 --> 00:35:49,900
and the glandular part.

626
00:35:52,650 --> 00:36:00,090
This region where the stalk
of the pituitary attaches

627
00:36:00,090 --> 00:36:02,030
is this region in
humans, where it's

628
00:36:02,030 --> 00:36:09,490
called the infundibular,
OK, for its cone shape.

629
00:36:09,490 --> 00:36:12,660
So when you see a
picture like this,

630
00:36:12,660 --> 00:36:15,640
where these
hypothalamic nuclei are,

631
00:36:15,640 --> 00:36:18,430
we're dealing mainly with
the medial hypothalamus.

632
00:36:18,430 --> 00:36:23,490
The mammillary bodies are
both medial and lateral.

633
00:36:23,490 --> 00:36:27,380
Posterior hypothalamic
areas is also broad.

634
00:36:27,380 --> 00:36:34,020
But it's mostly in the
medial hypothalamus.

635
00:36:34,020 --> 00:36:34,520
OK.

636
00:36:34,520 --> 00:36:43,915
So let's just do
quit with this one

637
00:36:43,915 --> 00:36:47,040
if somebody can answer this.

638
00:36:47,040 --> 00:36:49,400
Information about the
internal environment

639
00:36:49,400 --> 00:36:52,620
reaches the hypothalamus
by two major means.

640
00:36:52,620 --> 00:36:56,090
We've already talked about them.

641
00:36:56,090 --> 00:37:01,160
Now just see if you
can remember that?

642
00:37:01,160 --> 00:37:02,100
OK.

643
00:37:02,100 --> 00:37:04,360
Via the-- by the bloodstream.

644
00:37:04,360 --> 00:37:09,310
So it can reach the
hypothalamus by the bloodstream.

645
00:37:09,310 --> 00:37:12,020
Not just hormones,
but other means too.

646
00:37:12,020 --> 00:37:13,726
But things coming
through the blood.

647
00:37:13,726 --> 00:37:14,850
And what's the other means?

648
00:37:18,010 --> 00:37:19,580
If it doesn't come
through the blood

649
00:37:19,580 --> 00:37:24,575
to get to the hypothalamus, it
must come from neural pathways.

650
00:37:27,360 --> 00:37:32,920
Afferent fibers come in
mainly into the spinal cord.

651
00:37:32,920 --> 00:37:36,650
We call them visceral
afferent fibers, mostly

652
00:37:36,650 --> 00:37:38,040
through the vagus nerve.

653
00:37:38,040 --> 00:37:43,370
But for the head region, they
come through hypoglossal nerve.

654
00:37:43,370 --> 00:37:46,486
There's a few even in the
third nerve, but very few.

655
00:37:46,486 --> 00:37:47,860
They come in
through the seventh.

656
00:37:47,860 --> 00:37:51,510
They come in through the
ninth and tenth nerves.

657
00:37:51,510 --> 00:37:52,010
All right.

658
00:37:55,780 --> 00:37:57,900
But if they come there
through the blood,

659
00:37:57,900 --> 00:38:00,960
then we have got to understand
the blood-brain barrier.

660
00:38:00,960 --> 00:38:02,680
So we'll start with
that next time.

661
00:38:02,680 --> 00:38:05,970
I'll just show you
a few pictures.

662
00:38:05,970 --> 00:38:08,380
This is the interesting one.

663
00:38:08,380 --> 00:38:12,554
They inject HRP right
into the bloodstream.

664
00:38:12,554 --> 00:38:16,330
You know, way down in
the body someplace.

665
00:38:16,330 --> 00:38:19,010
And they see that in
most of the brain,

666
00:38:19,010 --> 00:38:21,045
you just see the HRP
in the capillaries.

667
00:38:21,045 --> 00:38:22,810
It never gets out.

668
00:38:22,810 --> 00:38:26,920
But in certain regions, it
leaks right into the tissue.

669
00:38:26,920 --> 00:38:31,770
The blood-brain barrier seems
to be very weak in some areas.

670
00:38:31,770 --> 00:38:34,210
So that's what this
picture is about.

671
00:38:34,210 --> 00:38:37,330
There's a better
one in the book, OK.