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PROFESSOR: OK, I
had told some of you

9
00:00:24,990 --> 00:00:26,515
that there would
be a quiz today.

10
00:00:30,130 --> 00:00:34,780
I won't give the quiz because
I didn't announce it online,

11
00:00:34,780 --> 00:00:37,750
but I would like you
to take it anyway.

12
00:00:37,750 --> 00:00:41,830
Take for your own benefit.

13
00:00:45,130 --> 00:00:46,140
So it won't count.

14
00:00:49,180 --> 00:00:55,170
I just want you to see
if you can write down

15
00:00:55,170 --> 00:00:59,470
the names of the 12
traditionally-named cranial

16
00:00:59,470 --> 00:01:02,760
nerves for humans.

17
00:01:02,760 --> 00:01:08,240
I want you to see if what you
remember-- just number them 1

18
00:01:08,240 --> 00:01:10,680
through 12 and see if
you remember their names,

19
00:01:10,680 --> 00:01:16,670
and see if you know which ones
are mixed nerve, which ones are

20
00:01:16,670 --> 00:01:20,200
purely motor, which
ones are purely sensory.

21
00:01:20,200 --> 00:01:23,215
Just try it.

22
00:01:23,215 --> 00:01:25,680
Just take a few minutes
and try to do that.

23
00:01:54,700 --> 00:01:56,720
And if you're not in
class, you're at home

24
00:01:56,720 --> 00:01:59,310
listening to this, I would
still like you to do it.

25
00:02:07,154 --> 00:02:08,570
And if you're home,
you can let me

26
00:02:08,570 --> 00:02:11,430
know by email how
many you have got.

27
00:02:30,120 --> 00:02:31,530
Do you need the mnemonic?

28
00:02:37,680 --> 00:02:42,210
On old Olympus' towering
top, a Finn and German

29
00:02:42,210 --> 00:02:43,350
viewed some hops.

30
00:02:47,230 --> 00:02:49,870
I don't know why, but I
can remember that mnemonic

31
00:02:49,870 --> 00:02:53,250
better than I can rem-- at
least when I was learning them,

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00:02:53,250 --> 00:02:54,090
I used it.

33
00:02:57,576 --> 00:03:06,620
On old Olympus' towering
top, a Finn and German

34
00:03:06,620 --> 00:03:08,133
viewed some hops.

35
00:03:12,067 --> 00:03:13,275
So use all the first letters.

36
00:03:50,100 --> 00:03:51,220
Write it?

37
00:03:51,220 --> 00:03:52,210
AUDIENCE: Yes.

38
00:03:52,210 --> 00:03:53,960
PROFESSOR: Just write
these first letters,

39
00:03:53,960 --> 00:04:06,800
on old Olympus', O-O-O, then
towering top, so O-O-O-T-P,

40
00:04:06,800 --> 00:04:18,895
a Finn, so A and F. A Finn
and German viewed some hops.

41
00:05:16,630 --> 00:05:20,150
OK, so there is a
table in the book which

42
00:05:20,150 --> 00:05:28,000
you can find, obviously
that occurs in those earlier

43
00:05:28,000 --> 00:05:34,102
chapters, but I keep
referring to cranial nerves

44
00:05:34,102 --> 00:05:34,935
throughout the book.

45
00:05:38,350 --> 00:05:43,491
How many of you think you
could name all of them?

46
00:05:43,491 --> 00:05:43,990
Yeah?

47
00:05:48,330 --> 00:05:58,020
Olfactory, optic, oculomotor,
trochlear, trigeminal,

48
00:05:58,020 --> 00:06:03,290
abducens, it's an
oculomotor nerve.

49
00:06:03,290 --> 00:06:05,210
AUDIENCE: Facial, [INAUDIBLE].

50
00:06:12,430 --> 00:06:15,625
PROFESSOR: So you give
10, 11 and 12 again.

51
00:06:15,625 --> 00:06:16,500
AUDIENCE: [INAUDIBLE]

52
00:06:19,075 --> 00:06:19,825
PROFESSOR: First--

53
00:06:19,825 --> 00:06:21,260
AUDIENCE: Oh, oh, vagus.

54
00:06:21,260 --> 00:06:24,250
PROFESSOR: Vagus nerve.

55
00:06:24,250 --> 00:06:29,040
Spinal accessory, OK, excellent.

56
00:06:29,040 --> 00:06:32,670
Now you need to know
just whether there

57
00:06:32,670 --> 00:06:38,310
are a few purely motor ones,
somatic motor, the oculomotor

58
00:06:38,310 --> 00:06:46,920
nerves, and the one
controlling the tongue,

59
00:06:46,920 --> 00:06:51,530
glossopharyngeal
nerve and the-- sorry,

60
00:06:51,530 --> 00:06:53,750
not the glossopharyngeal
but the hypoglossal.

61
00:07:03,750 --> 00:07:08,240
And of course there's several
purely sensory nerves.

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00:07:08,240 --> 00:07:11,080
The others are mixed.

63
00:07:11,080 --> 00:07:14,330
And the mixed
nerves always have--

64
00:07:14,330 --> 00:07:15,820
they're [? attached ?]
where they

65
00:07:15,820 --> 00:07:18,580
come in and join the brain.

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00:07:18,580 --> 00:07:24,090
Sort of in that middle region,
whereas the purely sensory ones

67
00:07:24,090 --> 00:07:26,465
in the hind brain are
like dorsal roots.

68
00:07:26,465 --> 00:07:28,460
They come in dorsally.

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00:07:28,460 --> 00:07:30,430
Purely motor ones are
like ventral roots.

70
00:07:38,990 --> 00:07:43,520
Except the trochlear
actually, doesn't actually

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00:07:43,520 --> 00:07:47,220
leave the cranium ventrally.

72
00:07:47,220 --> 00:07:52,450
It comes around, comes
up between the cerebellum

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00:07:52,450 --> 00:07:55,190
and the inferior colliculus,
and exits that way.

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00:08:01,600 --> 00:08:05,275
But it's very useful to
know these in neuroanatomy.

75
00:08:09,270 --> 00:08:09,840
All right.

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00:08:19,460 --> 00:08:26,260
Throughout the book I've
emphasized these two

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00:08:26,260 --> 00:08:32,312
structures, the medial pallium
and the corpus striatum.

78
00:08:32,312 --> 00:08:36,520
The early striatums, mainly
an olfactory structure,

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00:08:36,520 --> 00:08:39,940
but the striatum provided
the link to motor systems.

80
00:08:42,568 --> 00:08:46,600
And that's still true
of the whole striatum,

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00:08:46,600 --> 00:08:49,825
except it's not just
olfactory anymore.

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00:08:49,825 --> 00:08:52,370
And the other system
is the medial pallium,

83
00:08:52,370 --> 00:08:55,870
which as you probably remember
is the hippocampal formation.

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00:08:59,377 --> 00:09:03,260
But what did I suggest
was, even very early,

85
00:09:03,260 --> 00:09:07,190
was the role, the
major role, of these.

86
00:09:07,190 --> 00:09:13,130
They both concern learning, but
different types of learning.

87
00:09:13,130 --> 00:09:16,380
And you could see the
entire neocortex organized

88
00:09:16,380 --> 00:09:20,386
around these two systems,
two types of learning.

89
00:09:20,386 --> 00:09:26,530
Because cortical areas,
many cortical areas,

90
00:09:26,530 --> 00:09:29,470
have projections
that go towards one

91
00:09:29,470 --> 00:09:30,845
or the other of
these structures.

92
00:09:34,100 --> 00:09:36,080
So what is the
striatum involved in?

93
00:09:40,054 --> 00:09:40,970
What kind of learning?

94
00:09:44,050 --> 00:09:49,930
It's always sensory motor
habits of various sorts.

95
00:09:49,930 --> 00:09:53,250
But now we think it's much more
than sensory motor in higher

96
00:09:53,250 --> 00:09:54,530
primates.

97
00:09:54,530 --> 00:09:56,420
We think it's probably
habits of thought,

98
00:09:56,420 --> 00:09:58,170
habits of even feeling.

99
00:10:01,300 --> 00:10:05,860
A habit of feeling is
something like a prejudice,

100
00:10:05,860 --> 00:10:09,790
so your prejudices
probably depend

101
00:10:09,790 --> 00:10:13,368
on connections that
have been learned

102
00:10:13,368 --> 00:10:20,440
and the change that's occurred
in that parts of the striatum.

103
00:10:20,440 --> 00:10:24,730
And what about the medial
pallium or hippocampus?

104
00:10:24,730 --> 00:10:29,630
Originally a type
of memory, though,

105
00:10:29,630 --> 00:10:32,240
because what we just talked
about is all memory too.

106
00:10:32,240 --> 00:10:33,820
Habit memory is memory.

107
00:10:38,650 --> 00:10:49,050
Spatial memories, where
we are in the environment,

108
00:10:49,050 --> 00:10:52,850
episodic memory,
came out of this.

109
00:10:52,850 --> 00:10:56,530
And yes, it's become
important for navigating

110
00:10:56,530 --> 00:11:07,370
our cognitive space, our social
space, our imaginary spaces.

111
00:11:07,370 --> 00:11:10,390
But that's not
how it originated.

112
00:11:10,390 --> 00:11:14,940
It all evolved out of the
system for navigating the world

113
00:11:14,940 --> 00:11:18,490
and remembering, being
able to remember,

114
00:11:18,490 --> 00:11:20,960
good places and bad places.

115
00:11:20,960 --> 00:11:23,690
That required a somewhat
different kind of learning,

116
00:11:23,690 --> 00:11:26,280
different kinds
of algorithms had

117
00:11:26,280 --> 00:11:33,160
to evolve to underlie
those two kinds of memory.

118
00:11:33,160 --> 00:11:36,455
And then why did dorsal and
ventral parts of the striatum

119
00:11:36,455 --> 00:11:36,955
segregate?

120
00:11:39,600 --> 00:11:40,720
What was the big event?

121
00:11:45,360 --> 00:11:49,920
I said it was
olfactory originally,

122
00:11:49,920 --> 00:11:51,825
and that became
ventral striatum.

123
00:11:55,150 --> 00:11:59,410
So that should tell
you what happened.

124
00:11:59,410 --> 00:12:06,500
Other senses projected
mostly through the thalamus

125
00:12:06,500 --> 00:12:08,090
into the striatum also.

126
00:12:08,090 --> 00:12:11,450
And they took advantage
of that ability

127
00:12:11,450 --> 00:12:19,850
to form-- to change
connections that became habits.

128
00:12:19,850 --> 00:12:22,290
Obviously we don't just
form olfactory habits,

129
00:12:22,290 --> 00:12:29,540
we form visual motor habits.

130
00:12:29,540 --> 00:12:32,920
Think of the sports you
learn, think of simpler things

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00:12:32,920 --> 00:12:41,160
like riding a bicycle
or various things

132
00:12:41,160 --> 00:12:43,980
you learn when
you're growing up.

133
00:12:43,980 --> 00:12:46,410
Learning how to throw
a baseball properly,

134
00:12:46,410 --> 00:12:50,040
learning how to hit a baseball,
all these things in sports.

135
00:12:50,040 --> 00:12:51,880
But many things that
we don't even think

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00:12:51,880 --> 00:12:55,350
about, they're not sports,
they're things that we learn,

137
00:12:55,350 --> 00:12:56,220
part of our lives.

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00:12:59,540 --> 00:13:03,500
Those habits depend
on the striatum.

139
00:13:03,500 --> 00:13:08,990
And we call that kind of
memory, implicit memory,

140
00:13:08,990 --> 00:13:12,930
they are not-- we don't
remember individual events.

141
00:13:12,930 --> 00:13:17,180
If you're talking about
your memory for an event,

142
00:13:17,180 --> 00:13:21,260
where you learned how to ride
a bike, that's different,

143
00:13:21,260 --> 00:13:24,890
that's not a striatum,
but actually learning.

144
00:13:28,330 --> 00:13:34,900
We say, well, I know how to
type, I remember in my fingers.

145
00:13:34,900 --> 00:13:38,380
Well, that's striatal.

146
00:13:38,380 --> 00:13:38,880
All right.

147
00:13:44,330 --> 00:13:52,420
So I go through this,
call it a likely scenario,

148
00:13:52,420 --> 00:13:55,170
for the origins of
corpus striatum.

149
00:13:55,170 --> 00:14:02,430
And I'm just going to
go to this picture here,

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00:14:02,430 --> 00:14:05,390
this just summarises
that whole scenario.

151
00:14:05,390 --> 00:14:10,770
If you go through this, I
describe it in the book,

152
00:14:10,770 --> 00:14:13,970
that the beginnings is a
link between olfactory input

153
00:14:13,970 --> 00:14:15,116
and motor control.

154
00:14:18,080 --> 00:14:21,560
This is slide 37.

155
00:14:21,560 --> 00:14:24,410
And that became a ventral
striatum, that early link,

156
00:14:24,410 --> 00:14:28,530
and then I said,
well, the outputs

157
00:14:28,530 --> 00:14:36,510
went to the hypothalamus
as you see them drawn here

158
00:14:36,510 --> 00:14:38,430
in a primitive brain.

159
00:14:38,430 --> 00:14:40,510
And then the major
point that I added

160
00:14:40,510 --> 00:14:46,230
was that these were
modifiable links.

161
00:14:46,230 --> 00:14:50,040
And that was a big innovation,
different from spinal cord.

162
00:14:50,040 --> 00:14:52,430
You have a little bit of
learning in the spinal cord,

163
00:14:52,430 --> 00:14:53,800
but nothing like this.

164
00:14:56,830 --> 00:14:58,560
Types of learning you
get in spinal cord

165
00:14:58,560 --> 00:14:59,740
are rather short term.

166
00:14:59,740 --> 00:15:03,125
This is long term.

167
00:15:03,125 --> 00:15:05,470
These are the
formation of habits.

168
00:15:05,470 --> 00:15:08,760
And then I talk about
the non-olfact-- well,

169
00:15:08,760 --> 00:15:11,820
I talk about the feedback
you need for learning.

170
00:15:11,820 --> 00:15:16,080
We know that it involves
the dopamine pathways

171
00:15:16,080 --> 00:15:18,046
pretty heavily.

172
00:15:18,046 --> 00:15:22,425
We know that very early
taste as well as olfaction

173
00:15:22,425 --> 00:15:25,880
were important
sources of feedback

174
00:15:25,880 --> 00:15:29,870
that affected that system.

175
00:15:29,870 --> 00:15:32,955
And then I talk about
the non-olfactory inputs

176
00:15:32,955 --> 00:15:36,733
that resulted in a
dorsal striatum as well

177
00:15:36,733 --> 00:15:37,810
as ventral striatum.

178
00:15:41,009 --> 00:15:45,510
And then I talk about the early
expansions of the endbrain.

179
00:15:45,510 --> 00:15:50,470
It wasn't just the striatum,
but it was the pallium as well.

180
00:15:50,470 --> 00:15:54,516
Originally, the
pallium was olfactory,

181
00:15:54,516 --> 00:15:55,735
the olfactory cortex.

182
00:15:58,360 --> 00:16:03,810
But very, very early the
medial pallium began to evolve.

183
00:16:11,220 --> 00:16:13,710
We will look more at
that, I'll show you

184
00:16:13,710 --> 00:16:18,780
pictures of the way that
looks in non-mammals.

185
00:16:18,780 --> 00:16:20,620
You'll see, for
example, in the frog,

186
00:16:20,620 --> 00:16:24,450
the major pallial structure
is the medial pallium.

187
00:16:24,450 --> 00:16:29,370
They have a little bit of
structures adjacent to it,

188
00:16:29,370 --> 00:16:32,670
but they're just-- they provide
input to that medial pallium.

189
00:16:32,670 --> 00:16:36,110
It's called the dorsal
cortex, and yes, the neocortex

190
00:16:36,110 --> 00:16:37,330
did evolve out of that.

191
00:16:40,390 --> 00:16:44,570
OK, and then you
had the expansions

192
00:16:44,570 --> 00:16:46,550
of both the cortex
and the striatum.

193
00:16:50,850 --> 00:16:53,440
But the major change
that occurred in mammals

194
00:16:53,440 --> 00:17:00,570
was that a major output of the
striatum went to the cortex,

195
00:17:00,570 --> 00:17:03,130
because it projected
to the thalamus.

196
00:17:03,130 --> 00:17:04,301
So we'll see that.

197
00:17:04,301 --> 00:17:04,800
All right.

198
00:17:09,810 --> 00:17:16,230
We get a good idea about
origins and the relationship

199
00:17:16,230 --> 00:17:20,700
of different major segments of
the endbrain and other brain

200
00:17:20,700 --> 00:17:23,990
regions by looking
at gene expression.

201
00:17:23,990 --> 00:17:28,832
And this was one of the
earliest studies that did that.

202
00:17:28,832 --> 00:17:34,680
It showed that genes
expressed in neocortex as well

203
00:17:34,680 --> 00:17:41,120
as adjacent areas
like hippocampal area

204
00:17:41,120 --> 00:17:44,220
and the olfactory cortex.

205
00:17:44,220 --> 00:17:48,060
You can find closely
related genes

206
00:17:48,060 --> 00:17:55,390
in the hyperpallium of birds, in
the dorsal cortex of reptiles,

207
00:17:55,390 --> 00:17:59,650
including turtles, and in this
dorsal cortex of the frog.

208
00:17:59,650 --> 00:18:03,525
And that thick part there
is the medial pallium

209
00:18:03,525 --> 00:18:08,720
of the frog, that is the
hippocampal formation.

210
00:18:08,720 --> 00:18:11,160
And then you can see the
other genes are expressed

211
00:18:11,160 --> 00:18:15,570
in the striatal regions
and the adjoining septum.

212
00:18:15,570 --> 00:18:18,310
Notice that it goes all way
down to the base of the brain

213
00:18:18,310 --> 00:18:22,730
where the olfactory inputs
come in, even in mammals.

214
00:18:22,730 --> 00:18:28,200
And there is a corresponding
striatal area in the birds,

215
00:18:28,200 --> 00:18:32,810
in the reptiles, and
in the amphibians.

216
00:18:32,810 --> 00:18:34,620
And then there are
additional regions

217
00:18:34,620 --> 00:18:41,190
that aren't expressing the genes
of those two major regions.

218
00:18:41,190 --> 00:18:49,090
And that includes this in the
reptilian dorsal ventricular

219
00:18:49,090 --> 00:18:51,528
ridge area.

220
00:18:51,528 --> 00:18:56,370
In birds, there is also a
dorsal ventricular ridge area.

221
00:18:56,370 --> 00:19:00,820
It isn't called that
anymore in the adult bird,

222
00:19:00,820 --> 00:19:05,540
but its connections
are pallial-like,

223
00:19:05,540 --> 00:19:08,160
and that's true in
the reptiles too.

224
00:19:08,160 --> 00:19:10,480
But if you look at
mammals, you don't

225
00:19:10,480 --> 00:19:15,190
find that gene expressed
in the neocortex.

226
00:19:15,190 --> 00:19:19,230
You find it mainly
here in the amygdala.

227
00:19:19,230 --> 00:19:21,870
But we know now
that the amygdala

228
00:19:21,870 --> 00:19:31,850
does get projections of various
senses, somewhat like cortex.

229
00:19:31,850 --> 00:19:37,150
And we also know that from
these subcortical regions

230
00:19:37,150 --> 00:19:41,195
there are cells migrating
to the neocortex.

231
00:19:41,195 --> 00:19:44,270
And this just shows,
from more recent studies,

232
00:19:44,270 --> 00:19:46,180
the same picture holds.

233
00:19:46,180 --> 00:19:48,490
But it shows how
come-- this is just

234
00:19:48,490 --> 00:19:51,255
to give you an idea of the
complexity of these gene

235
00:19:51,255 --> 00:19:53,470
expression studies.

236
00:19:53,470 --> 00:20:01,100
And because the gene expression
studies don't always-- they

237
00:20:01,100 --> 00:20:04,470
are sometimes hard to interpret
because of the number of genes

238
00:20:04,470 --> 00:20:07,980
involved and the relative
degree of expression.

239
00:20:07,980 --> 00:20:11,850
I still like the studies that
depend more on connections,

240
00:20:11,850 --> 00:20:15,470
and the reason for that is
that the connections are what

241
00:20:15,470 --> 00:20:19,090
underlies behavior,
and the behavior

242
00:20:19,090 --> 00:20:24,840
is really critical in evolution.

243
00:20:24,840 --> 00:20:31,740
Brains change in order
to change function,

244
00:20:31,740 --> 00:20:34,510
which of course
includes behavior.

245
00:20:34,510 --> 00:20:39,390
This just gives you another
view, one based on connections.

246
00:20:39,390 --> 00:20:45,650
This is Karten and one of
his students publishing back

247
00:20:45,650 --> 00:20:47,720
in 1989.

248
00:20:47,720 --> 00:20:50,570
Karten was the guy who was
at MIT with [? Nauda ?]

249
00:20:50,570 --> 00:20:54,400
and was the first to discover
these pathways in birds

250
00:20:54,400 --> 00:20:58,250
from thalamus carrying
visual and auditory

251
00:20:58,250 --> 00:21:01,520
information to that
big subcortical region

252
00:21:01,520 --> 00:21:02,155
in the birds.

253
00:21:12,540 --> 00:21:16,230
This was more like neocortex
up here, the hyperpallium,

254
00:21:16,230 --> 00:21:21,600
but this region here
also had connections just

255
00:21:21,600 --> 00:21:24,825
like neocortex.

256
00:21:24,825 --> 00:21:25,325
All right.

257
00:21:28,010 --> 00:21:32,770
So he related the specific
kinds of connections in mammals

258
00:21:32,770 --> 00:21:37,900
to similar connections in birds
and where they were located.

259
00:21:44,400 --> 00:21:47,280
So then I discuss the
medial pallium a little bit.

260
00:21:47,280 --> 00:21:51,000
We've already done that.

261
00:21:51,000 --> 00:21:54,140
But I wanted to point out this
one rather interesting study,

262
00:21:54,140 --> 00:21:57,810
it's a highly cited study.

263
00:21:57,810 --> 00:22:00,280
This was a group
of investigators

264
00:22:00,280 --> 00:22:08,580
who realized that in
one genus of birds,

265
00:22:08,580 --> 00:22:13,702
there were some birds
that formed food caches,

266
00:22:13,702 --> 00:22:18,260
they stored food when
food was plentiful,

267
00:22:18,260 --> 00:22:20,556
and then they had to
remember where they put it.

268
00:22:20,556 --> 00:22:24,880
They had to remember well
above chance levels for it

269
00:22:24,880 --> 00:22:25,820
to be really adaptive.

270
00:22:29,610 --> 00:22:33,170
Whereas other members of the
very same genus didn't do that.

271
00:22:36,000 --> 00:22:41,500
So these people studied the
brains of these two groups

272
00:22:41,500 --> 00:22:48,470
of birds and other songbirds
as well that formed these food

273
00:22:48,470 --> 00:22:53,180
storage locations, the food
caches, and those that didn't.

274
00:22:53,180 --> 00:22:59,670
And this is a plot of the
size of the hippocampus

275
00:22:59,670 --> 00:23:04,056
versus the volume of
the whole telencephalon,

276
00:23:04,056 --> 00:23:07,100
the whole endbrain.

277
00:23:07,100 --> 00:23:10,470
And you can see here
this is the dimension

278
00:23:10,470 --> 00:23:12,720
you want to pay attention to.

279
00:23:12,720 --> 00:23:15,510
OK?

280
00:23:15,510 --> 00:23:18,580
How far they are from that
diagonal line, and you can see

281
00:23:18,580 --> 00:23:19,785
there's no overlap.

282
00:23:19,785 --> 00:23:22,420
The birds that formed the food
caches had bigger hippocampus.

283
00:23:26,370 --> 00:23:31,330
So the correlations
aren't just statistically

284
00:23:31,330 --> 00:23:32,540
reliable, they're dramatic.

285
00:23:35,540 --> 00:23:39,636
Animals need that structure
for spatial memory.

286
00:23:39,636 --> 00:23:40,950
AUDIENCE: [INAUDIBLE]

287
00:23:40,950 --> 00:23:41,805
PROFESSOR: Sorry?

288
00:23:41,805 --> 00:23:45,579
AUDIENCE: What's the
difference in [INAUDIBLE]?

289
00:23:45,579 --> 00:23:46,620
PROFESSOR: Difference in?

290
00:23:46,620 --> 00:23:51,560
Oh, the members of
the one group, these

291
00:23:51,560 --> 00:23:53,810
are all the same genes.

292
00:23:53,810 --> 00:23:55,530
The triangles.

293
00:23:55,530 --> 00:23:59,660
The others are not
members of that genus.

294
00:23:59,660 --> 00:24:03,054
I did reproduce this,
I believe, in the book,

295
00:24:03,054 --> 00:24:04,980
so you can find the source.

296
00:24:04,980 --> 00:24:10,840
And I probably spelled some
of that out in the legend.

297
00:24:10,840 --> 00:24:12,180
All right.

298
00:24:12,180 --> 00:24:13,805
And then there was
a parallel evolution

299
00:24:13,805 --> 00:24:18,900
of the pallial and subpallial
structures, expansion of both,

300
00:24:18,900 --> 00:24:22,916
although we know that it was
the pallial structures that

301
00:24:22,916 --> 00:24:25,506
expanded the most,
especially in mammals

302
00:24:25,506 --> 00:24:27,150
with the evolution of neocortex.

303
00:24:32,140 --> 00:24:36,200
So I pretty much
answered question eight,

304
00:24:36,200 --> 00:24:39,470
part of the primitive endbrain
that the neocortex evolved from

305
00:24:39,470 --> 00:24:41,910
was that dorsal cortex.

306
00:24:41,910 --> 00:24:47,110
There's a
parahippocampal region,

307
00:24:47,110 --> 00:24:51,315
and it's supported by
gene expression data.

308
00:24:55,710 --> 00:24:58,080
And you should know
that some mammals

309
00:24:58,080 --> 00:25:00,000
have a very small neocortex.

310
00:25:00,000 --> 00:25:05,390
Although having a neocortex is
fundamental to being a mammal,

311
00:25:05,390 --> 00:25:11,510
not just having mammary glands
and some other characteristics,

312
00:25:11,510 --> 00:25:15,920
hair on the skin and so forth.

313
00:25:15,920 --> 00:25:21,960
I redrew the gross views here
of a couple of hedgehogs.

314
00:25:21,960 --> 00:25:26,760
European hedgehogs just have
a really small neocortex,

315
00:25:26,760 --> 00:25:28,465
smaller than the hamster.

316
00:25:28,465 --> 00:25:34,370
A West African hedgehog,
a possum, a prairie vole,

317
00:25:34,370 --> 00:25:38,470
they're all fairly
similar to a hamster.

318
00:25:38,470 --> 00:25:40,955
And the relatively
slightly larger

319
00:25:40,955 --> 00:25:44,510
are animals like the vole
and mouse, other voles

320
00:25:44,510 --> 00:25:48,210
and mouse, rat.

321
00:25:48,210 --> 00:25:51,580
And these are what cross
sections look like.

322
00:25:51,580 --> 00:25:53,825
Here we have a tenrec.

323
00:25:53,825 --> 00:25:59,820
It's another animal that like
the European hedgehog has,

324
00:25:59,820 --> 00:26:03,075
I think relatively speaking,
the smallest neocortex

325
00:26:03,075 --> 00:26:04,896
of all the mammals.

326
00:26:04,896 --> 00:26:09,850
And that's shown in this
section through the middle

327
00:26:09,850 --> 00:26:10,665
of the brain.

328
00:26:10,665 --> 00:26:13,400
This is the mid-frontal
section through the middle

329
00:26:13,400 --> 00:26:14,790
of the hemisphere.

330
00:26:14,790 --> 00:26:19,220
You see the neocortex is even
smaller, or at least no bigger,

331
00:26:19,220 --> 00:26:21,540
than the whole
hippocampus there.

332
00:26:21,540 --> 00:26:23,330
And this is all
olfactory cortex.

333
00:26:30,300 --> 00:26:33,275
And then the opossums
and the hedgehogs

334
00:26:33,275 --> 00:26:36,810
also have relatively
small neocortexes.

335
00:26:36,810 --> 00:26:41,920
OK, and then we went
through these pictures,

336
00:26:41,920 --> 00:26:43,580
and now we want to do this.

337
00:26:43,580 --> 00:26:45,170
We want to get
started with talking

338
00:26:45,170 --> 00:26:46,566
about the limbic
system, and this

339
00:26:46,566 --> 00:26:49,040
will be the first
session on that.

340
00:26:49,040 --> 00:26:51,390
Stressing the hypothalamus
at the beginning,

341
00:26:51,390 --> 00:26:53,436
and then we'll
talk about striatum

342
00:26:53,436 --> 00:26:54,885
and then the neocortex.

343
00:27:05,030 --> 00:27:06,656
All right.

344
00:27:06,656 --> 00:27:11,550
So this is actually
called class 28.

345
00:27:11,550 --> 00:27:16,530
When I put the slides up after
the class I call them sessions,

346
00:27:16,530 --> 00:27:19,060
so they will start
with the slides we just

347
00:27:19,060 --> 00:27:23,520
covered on the
forebrain introduction.

348
00:27:26,268 --> 00:27:27,860
OK, so what is that term?

349
00:27:27,860 --> 00:27:29,596
Where does it come from?

350
00:27:29,596 --> 00:27:31,380
Why do we call it limbic system?

351
00:27:34,740 --> 00:27:36,180
AUDIENCE: [INAUDIBLE]

352
00:27:36,180 --> 00:27:37,140
PROFESSOR: Sorry?

353
00:27:37,140 --> 00:27:40,020
AUDIENCE: Doesn't "limbic"
mean the edge of something?

354
00:27:40,020 --> 00:27:41,410
PROFESSOR: Yeah, the fringe.

355
00:27:41,410 --> 00:27:43,275
The fringe or border or edge.

356
00:27:50,350 --> 00:28:01,310
It came-- I must have brought
that up a little bit later.

357
00:28:01,310 --> 00:28:04,890
Let's come back to
that in a minute,

358
00:28:04,890 --> 00:28:07,810
and talk about
the structure that

359
00:28:07,810 --> 00:28:10,513
is central to any discussion
of the limbic system,

360
00:28:10,513 --> 00:28:14,650
the hypothalamus,
and why it became

361
00:28:14,650 --> 00:28:19,510
important to separate out
an endbrain system that

362
00:28:19,510 --> 00:28:23,160
was closely connected with it.

363
00:28:23,160 --> 00:28:24,760
All the endbrain
structures that we

364
00:28:24,760 --> 00:28:28,450
call limbic system, or
limbic endbrain system,

365
00:28:28,450 --> 00:28:32,110
are all closely connected
to the hypothalamus.

366
00:28:32,110 --> 00:28:34,470
Sherrington, remember,
called it the head ganglion

367
00:28:34,470 --> 00:28:37,490
of the autonomic nervous system.

368
00:28:37,490 --> 00:28:41,800
It's much more than
that, because it controls

369
00:28:41,800 --> 00:28:48,200
motivated behavior including
eating, defending, attacking.

370
00:28:48,200 --> 00:28:53,506
The structures there
underlie motivational states,

371
00:28:53,506 --> 00:28:54,285
the drives.

372
00:28:56,810 --> 00:29:00,055
And of course they're
associated with strong feelings,

373
00:29:00,055 --> 00:29:02,590
so we also associate
it with emotion.

374
00:29:05,170 --> 00:29:08,205
And we call them, when we
talked about motor system,

375
00:29:08,205 --> 00:29:12,170
we called them central
pattern generators.

376
00:29:12,170 --> 00:29:18,692
This is the picture
of-- what it shows

377
00:29:18,692 --> 00:29:22,318
is the locomotor
hierarchy with the pattern

378
00:29:22,318 --> 00:29:24,270
generators in the spinal cord.

379
00:29:24,270 --> 00:29:28,260
Here's the motor neurons.

380
00:29:28,260 --> 00:29:33,350
And then, in the
midbrain and 'tweenbrain,

381
00:29:33,350 --> 00:29:38,440
Swanson called the
structures that

382
00:29:38,440 --> 00:29:43,270
initiated locomotion
the locomotor pattern

383
00:29:43,270 --> 00:29:45,210
initiator, the
midbrain locomotor

384
00:29:45,210 --> 00:29:48,190
region, and the
locomotor pattern

385
00:29:48,190 --> 00:29:53,600
controller, the hypothalamic
locomotor region.

386
00:29:53,600 --> 00:29:55,182
And when we're in
the hypothalamus,

387
00:29:55,182 --> 00:29:58,170
we're concerned
with structures that

388
00:29:58,170 --> 00:30:01,820
underlie what we call
the biological drives.

389
00:30:01,820 --> 00:30:04,235
So why is there a
locomotor pattern generator

390
00:30:04,235 --> 00:30:05,320
in the hypothalamus?

391
00:30:07,950 --> 00:30:10,865
It doesn't directly
control locomotion.

392
00:30:10,865 --> 00:30:15,340
It controls the structures
in the midbrain and hindbrain

393
00:30:15,340 --> 00:30:19,035
and spinal cord that
underlie locomotor movements.

394
00:30:23,810 --> 00:30:27,990
But with every drive,
think of hunger drive.

395
00:30:27,990 --> 00:30:30,175
Locomotion is always involved.

396
00:30:30,175 --> 00:30:37,440
If an animal has a high level
of hunger, he will move more.

397
00:30:37,440 --> 00:30:40,470
Unless he's so hungry,
he's getting weak.

398
00:30:40,470 --> 00:30:43,410
But that comes rather late,
we're talking about just

399
00:30:43,410 --> 00:30:45,116
in the normal state.

400
00:30:45,116 --> 00:30:46,490
When you're
hungrier, you're more

401
00:30:46,490 --> 00:30:50,335
likely to locomote to the
refrigerator or to the store.

402
00:30:53,827 --> 00:30:58,080
But think of animals who
are motivated to forage.

403
00:30:58,080 --> 00:31:02,560
Or if they're food storing
animals, like a hungry hamster,

404
00:31:02,560 --> 00:31:04,880
will only forage at
certain times of day

405
00:31:04,880 --> 00:31:13,370
when he's safest, when the
sun is very low in the sky.

406
00:31:13,370 --> 00:31:16,936
But other times
when he's hungry,

407
00:31:16,936 --> 00:31:21,060
he will generate locomotion
to get to the places

408
00:31:21,060 --> 00:31:22,865
where he's stored food.

409
00:31:22,865 --> 00:31:27,540
And he has an elaborate tunnel,
and will go to various places

410
00:31:27,540 --> 00:31:29,500
in his tunnel to do that.

411
00:31:29,500 --> 00:31:33,820
So locomotion is associated
with all the drives.

412
00:31:33,820 --> 00:31:37,462
So it is connected to the other
neurons in the hypothalamus

413
00:31:37,462 --> 00:31:41,060
that underlie the various
motivational states.

414
00:31:43,820 --> 00:31:51,100
So now the cortical layers
that we call limbic endbrain

415
00:31:51,100 --> 00:31:55,220
structures, they are closely
connected to the hypothalamus.

416
00:31:55,220 --> 00:31:56,392
Where are they found?

417
00:31:58,990 --> 00:32:04,080
And that tells you the origin
of the term limbic system.

418
00:32:04,080 --> 00:32:06,560
We already discussed
the meaning.

419
00:32:06,560 --> 00:32:13,840
The term came from Paul
Broca, Pierre Paul Broca,

420
00:32:13,840 --> 00:32:20,470
who used this phrase, "the
great limbic lobe," in French

421
00:32:20,470 --> 00:32:24,220
in 1878, for the human brain.

422
00:32:24,220 --> 00:32:26,950
But I have to point out that
that doesn't mean that Broca

423
00:32:26,950 --> 00:32:31,230
understood the functions,
OK, or the connections,

424
00:32:31,230 --> 00:32:33,883
because the methods
simply weren't good enough

425
00:32:33,883 --> 00:32:35,060
for him to know that.

426
00:32:38,010 --> 00:32:43,740
It wasn't until the 20th century
that we began to realize that.

427
00:32:43,740 --> 00:32:48,560
But what Broca called
the great limbic lobe,

428
00:32:48,560 --> 00:32:50,150
you have to look at
a human hemisphere

429
00:32:50,150 --> 00:32:53,140
from the medial side.

430
00:32:53,140 --> 00:32:57,140
And this particular
picture of the human brain

431
00:32:57,140 --> 00:33:01,910
on top and rodent
brains down below,

432
00:33:01,910 --> 00:33:04,810
I've divided it according
to major functions.

433
00:33:04,810 --> 00:33:10,550
And I say that these are
all structures closely tied

434
00:33:10,550 --> 00:33:13,870
to motivational states
because they're closely

435
00:33:13,870 --> 00:33:16,075
linked to the hypothalamus.

436
00:33:16,075 --> 00:33:21,340
And notice that they're
always around this edge

437
00:33:21,340 --> 00:33:24,124
of the hemisphere.

438
00:33:24,124 --> 00:33:26,480
So if you start just
at the corpus callosum

439
00:33:26,480 --> 00:33:29,480
and go just above it,
you're in limbic areas

440
00:33:29,480 --> 00:33:31,656
of singular cortex.

441
00:33:31,656 --> 00:33:34,380
These are the
parolfactory regions.

442
00:33:34,380 --> 00:33:40,810
The orbital frontal region is
closely connected to these.

443
00:33:40,810 --> 00:33:43,660
Broca's area would
not be included.

444
00:33:43,660 --> 00:33:47,560
This would be Broca's
area here, and this

445
00:33:47,560 --> 00:33:52,350
would be the area controlling
the movements of speaking,

446
00:33:52,350 --> 00:34:00,160
just behind Broca's area but in
the motor areas of the cortex.

447
00:34:00,160 --> 00:34:03,000
But that doesn't mean
that Broca's area is not

448
00:34:03,000 --> 00:34:04,820
connected to these areas.

449
00:34:04,820 --> 00:34:05,710
It is.

450
00:34:05,710 --> 00:34:11,260
The various, multi-sensory
association areas of cortex

451
00:34:11,260 --> 00:34:15,760
are the areas most closely tied
to these limbic structures.

452
00:34:15,760 --> 00:34:19,810
We often call them
paralimbic, and reserve

453
00:34:19,810 --> 00:34:22,929
the term limbic structures to
the subcortical structures that

454
00:34:22,929 --> 00:34:26,036
are closely tied
to the brain stem.

455
00:34:26,036 --> 00:34:29,019
But the paralimbic structures
are these structures

456
00:34:29,019 --> 00:34:30,150
that are near that.

457
00:34:32,750 --> 00:34:39,370
But that's the great limbic
lobe that forms this whole ring.

458
00:34:39,370 --> 00:34:41,350
The medial edge of the
brain, and here you

459
00:34:41,350 --> 00:34:43,239
see them in a rodent brain.

460
00:34:43,239 --> 00:34:47,125
Some of this would be connected
to the [? MD, ?] which means

461
00:34:47,125 --> 00:34:52,020
it's prefrontal neocortex, but
in the rodent those areas get

462
00:34:52,020 --> 00:34:56,137
connections from the
anterior nuclei too,

463
00:34:56,137 --> 00:34:58,220
which cannot be the
[? singular. ?] We'll be going

464
00:34:58,220 --> 00:34:59,690
over that.

465
00:34:59,690 --> 00:35:02,660
So I've shown that
ring of cortical areas,

466
00:35:02,660 --> 00:35:06,900
there, indicated by the arrow
here, just on the medial view.

467
00:35:06,900 --> 00:35:09,100
But we include with it
the olfactory areas.

468
00:35:09,100 --> 00:35:10,990
So here you see
it in the rodent.

469
00:35:10,990 --> 00:35:17,490
I've used that same designation
because the olfactory areas

470
00:35:17,490 --> 00:35:19,820
are paralimbic
too in that sense.

471
00:35:19,820 --> 00:35:24,490
They are closely linked
to the hypothalamus.

472
00:35:24,490 --> 00:35:27,255
And then I continue that
designation here on the brain

473
00:35:27,255 --> 00:35:30,900
stem, and I show the
hypothalamus and epithalamus

474
00:35:30,900 --> 00:35:39,185
marked that way, and I show it
continuing into the midbrain,

475
00:35:39,185 --> 00:35:44,880
as [? Nauda ?] described in his
work on the cats and monkeys

476
00:35:44,880 --> 00:35:45,380
primarily.

477
00:35:48,410 --> 00:35:52,280
OK, now there are
various types of studies

478
00:35:52,280 --> 00:35:58,940
that separate limbic system
areas from what we've

479
00:35:58,940 --> 00:36:02,340
been calling somatic areas,
the non-limbic areas.

480
00:36:05,050 --> 00:36:07,640
And when it was done
a number of years

481
00:36:07,640 --> 00:36:13,600
ago in describing systems in
the brain that cause arousal,

482
00:36:13,600 --> 00:36:19,020
in electrical
stimulation studies

483
00:36:19,020 --> 00:36:22,310
and in behavioral
studies, aroused animals

484
00:36:22,310 --> 00:36:26,080
are very different
from unaroused animals.

485
00:36:26,080 --> 00:36:28,650
So let's just go through
that a little bit

486
00:36:28,650 --> 00:36:33,830
and talk about the two arousal
systems in the midbrain.

487
00:36:33,830 --> 00:36:36,076
One of them we associate
with the midbrain reticular

488
00:36:36,076 --> 00:36:36,575
formation.

489
00:36:36,575 --> 00:36:38,490
It's somatic.

490
00:36:38,490 --> 00:36:40,670
The other is associated
with the limbic areas.

491
00:36:43,530 --> 00:36:50,590
So we've already
seen this picture

492
00:36:50,590 --> 00:36:54,910
when we talked about
midbrain and diencephalon

493
00:36:54,910 --> 00:36:57,490
and those chapters
where I was introducing

494
00:36:57,490 --> 00:36:59,790
all the various levels of brain.

495
00:36:59,790 --> 00:37:03,390
So there are the limbic
midbrain areas [INAUDIBLE]

496
00:37:03,390 --> 00:37:07,590
central gray area and the
ventral tegmental area.

497
00:37:07,590 --> 00:37:08,970
And the rest are all somatic.

498
00:37:08,970 --> 00:37:12,780
And the part with the
horizontal black lines,

499
00:37:12,780 --> 00:37:17,100
here in the midbrain picture,
is called the midbrain reticular

500
00:37:17,100 --> 00:37:18,690
formation.

501
00:37:18,690 --> 00:37:20,010
OK.

502
00:37:20,010 --> 00:37:22,720
And that's the area,
you can get arousal

503
00:37:22,720 --> 00:37:26,070
from stimulating
anywhere in the midbrain,

504
00:37:26,070 --> 00:37:32,592
but it's that region where
you primarily get arousal.

505
00:37:32,592 --> 00:37:36,666
And you get it from stimulating
those limbic areas too.

506
00:37:36,666 --> 00:37:38,420
But then I'm asking
this question.

507
00:37:38,420 --> 00:37:41,646
I want you to compare
the two arousal systems.

508
00:37:41,646 --> 00:37:43,220
What structures are involved?

509
00:37:43,220 --> 00:37:44,695
Well, we just mentioned that.

510
00:37:44,695 --> 00:37:47,260
What are the major
types of connections

511
00:37:47,260 --> 00:37:48,835
of these structures?

512
00:37:48,835 --> 00:37:50,793
What are the effects of
electrical stimulation?

513
00:37:53,390 --> 00:37:57,466
Is there habituation when you
use electrical stimulation?

514
00:37:57,466 --> 00:37:59,760
If you just keep the
stimulation on one point

515
00:37:59,760 --> 00:38:03,220
and stimulate again
and again, do you

516
00:38:03,220 --> 00:38:04,510
keep getting the same effect?

517
00:38:04,510 --> 00:38:06,340
Or do you get habituation?

518
00:38:06,340 --> 00:38:10,425
It's very different
for the two systems.

519
00:38:10,425 --> 00:38:12,280
Just like they give
different inputs,

520
00:38:12,280 --> 00:38:15,240
the effects of electrical
stimulation are different.

521
00:38:15,240 --> 00:38:18,020
What are the differences?

522
00:38:18,020 --> 00:38:21,680
It's a complex question.

523
00:38:21,680 --> 00:38:22,180
OK.

524
00:38:22,180 --> 00:38:23,800
Does anybody want
to say anything?

525
00:38:26,734 --> 00:38:34,069
AUDIENCE: So the non-limbic
system is more physical

526
00:38:34,069 --> 00:38:39,448
responses to, with physical
manifestations of, arousal

527
00:38:39,448 --> 00:38:40,440
whereas--

528
00:38:40,440 --> 00:38:43,400
PROFESSOR: What do you mean?

529
00:38:43,400 --> 00:38:45,975
Physical manifestations
of arousal?

530
00:38:45,975 --> 00:38:48,015
In non-limbic?

531
00:38:48,015 --> 00:38:50,098
AUDIENCE: And then limbic
would be more associated

532
00:38:50,098 --> 00:38:52,090
with pleasure.

533
00:38:52,090 --> 00:38:54,220
PROFESSOR: OK, so
you're saying limbic

534
00:38:54,220 --> 00:38:56,970
is associated with
[? affect ?] feelings,

535
00:38:56,970 --> 00:39:02,600
positive or negative feelings,
pleasurable or not pleasurable.

536
00:39:02,600 --> 00:39:05,540
The opposite-- unpleasant
or very pleasant.

537
00:39:05,540 --> 00:39:06,570
And that's all correct.

538
00:39:09,270 --> 00:39:13,090
What kind of inputs
did they get?

539
00:39:13,090 --> 00:39:15,710
They get different
kinds of inputs.

540
00:39:15,710 --> 00:39:19,010
Those limbic areas--
what kind of inputs

541
00:39:19,010 --> 00:39:20,420
are they getting from below?

542
00:39:24,310 --> 00:39:27,975
They're the inputs that come in
mainly through the vagus nerve.

543
00:39:30,630 --> 00:39:33,020
From the viscera.

544
00:39:33,020 --> 00:39:39,300
They're visceral inputs,
OK, visceral sensory inputs.

545
00:39:43,280 --> 00:39:46,749
From above, they come
from hypothalamus

546
00:39:46,749 --> 00:39:48,040
and limbic endbrain structures.

547
00:39:50,840 --> 00:39:52,670
OK.

548
00:39:52,670 --> 00:39:57,670
Now the non-limbic areas
get all the various inputs

549
00:39:57,670 --> 00:40:02,226
from the various sensory systems
and also from the cerebellum,

550
00:40:02,226 --> 00:40:05,170
that is the motor system
and sensory systems.

551
00:40:09,122 --> 00:40:12,420
So there are these
big differences.

552
00:40:12,420 --> 00:40:16,380
We've shown how they're located
in different places, the types

553
00:40:16,380 --> 00:40:21,150
of inputs, and the types of
outputs are different too.

554
00:40:21,150 --> 00:40:21,650
OK.

555
00:40:25,390 --> 00:40:31,280
Now, electrical
simulation, both systems

556
00:40:31,280 --> 00:40:36,450
cause the arousal patterns
in the electroencephalogram.

557
00:40:36,450 --> 00:40:38,680
That is, you're recording
with large electrodes,

558
00:40:38,680 --> 00:40:41,570
recording from the
scalp of a human.

559
00:40:41,570 --> 00:40:46,055
You get this fast,
high frequency pattern.

560
00:40:50,050 --> 00:40:52,570
Very different from the
pattern of a drowsy person

561
00:40:52,570 --> 00:40:54,550
or a sleeping person.

562
00:40:54,550 --> 00:40:55,050
OK.

563
00:41:00,640 --> 00:41:04,050
And if you stimulate
repeatedly in the same place

564
00:41:04,050 --> 00:41:09,720
in the midbrain, the effects
decrease, you get habituation.

565
00:41:09,720 --> 00:41:11,940
If you move the
site where you're

566
00:41:11,940 --> 00:41:15,550
stimulating a little bit,
the arousal comes back.

567
00:41:15,550 --> 00:41:21,140
So just like behavioral
effects of novel stimulation

568
00:41:21,140 --> 00:41:24,856
that habituate as the stimulus
becomes more familiar.

569
00:41:29,140 --> 00:41:34,790
Now if you do the same thing
in the limbic structures,

570
00:41:34,790 --> 00:41:36,880
you get the EEG
arousal, all right,

571
00:41:36,880 --> 00:41:38,930
but it doesn't go away
with repeated stimulation.

572
00:41:42,330 --> 00:41:46,910
It's a little bit
more like someone

573
00:41:46,910 --> 00:41:49,220
calling your name
repeatedly, thus

574
00:41:49,220 --> 00:41:52,350
stimulating the limbic
system a lot more.

575
00:41:52,350 --> 00:41:56,790
We tend to be pretty
attached to our name,

576
00:41:56,790 --> 00:41:58,960
and we don't habituate
readily at all.

577
00:42:04,760 --> 00:42:08,326
Just like we don't habituate
readily to good taste in food

578
00:42:08,326 --> 00:42:10,331
if we're hungry.

579
00:42:10,331 --> 00:42:15,420
If we're not hungry, sure,
but that's something else.

580
00:42:15,420 --> 00:42:17,340
We just keep everything
else constant.

581
00:42:17,340 --> 00:42:18,830
Hunger is constant.

582
00:42:18,830 --> 00:42:21,620
You keep responding,
you don't habituate,

583
00:42:21,620 --> 00:42:24,511
at least not very much.

584
00:42:24,511 --> 00:42:25,010
OK.

585
00:42:28,580 --> 00:42:31,690
Now you said pleasant
and unpleasant.

586
00:42:31,690 --> 00:42:37,480
If you're in the
non-limbic areas,

587
00:42:37,480 --> 00:42:42,074
there is a very mild rewarding
effect of being stimulated.

588
00:42:42,074 --> 00:42:44,490
But if someone's very sleepy,
it's probably non-rewarding.

589
00:42:48,350 --> 00:42:50,530
But if you're in
those limbic areas,

590
00:42:50,530 --> 00:42:52,280
and you're up and
around the central gray,

591
00:42:52,280 --> 00:42:56,710
it's generally
negatively rewarding.

592
00:42:56,710 --> 00:42:58,410
If you stimulate
an animal there,

593
00:42:58,410 --> 00:43:00,930
they generally
will work in order

594
00:43:00,930 --> 00:43:05,350
to be able to-- they'll do
something, take some action,

595
00:43:05,350 --> 00:43:06,940
if they've learned
how to turn it off.

596
00:43:06,940 --> 00:43:09,690
And they will work to
be able to turn it off.

597
00:43:09,690 --> 00:43:11,649
They don't like to
be stimulated there.

598
00:43:11,649 --> 00:43:13,440
Whereas if you're in
those ventral regions,

599
00:43:13,440 --> 00:43:16,320
the ventral tegmental
area, we say

600
00:43:16,320 --> 00:43:19,856
you get high levels
of self stimulation.

601
00:43:19,856 --> 00:43:23,785
That is, they will turn the
stimulus on by themselves.

602
00:43:26,740 --> 00:43:28,060
They very quickly learn.

603
00:43:28,060 --> 00:43:34,020
It's a very effective way to
train animals to do things

604
00:43:34,020 --> 00:43:37,640
if you have the electrodes
placed in those areas

605
00:43:37,640 --> 00:43:39,131
and they can stimulate.

606
00:43:42,120 --> 00:43:43,560
And then I just
talk a little bit

607
00:43:43,560 --> 00:43:46,600
about ascending and
descending connections.

608
00:43:46,600 --> 00:43:53,543
I do the same thing here for
the second type of arousal,

609
00:43:53,543 --> 00:43:55,650
you can call it limbic arousal.

610
00:43:59,880 --> 00:44:03,610
And notice here I mention,
besides the hypothalamus,

611
00:44:03,610 --> 00:44:08,140
connections to the
limbic midbrain area.

612
00:44:08,140 --> 00:44:10,300
These are the other
major forebrain

613
00:44:10,300 --> 00:44:13,490
systems besides hypothalamus.

614
00:44:13,490 --> 00:44:17,210
I didn't mention epithalamus,
but it should be included.

615
00:44:17,210 --> 00:44:21,200
But in the endbrain
septal area in front

616
00:44:21,200 --> 00:44:23,724
of the thalamus right
between the hemispheres

617
00:44:23,724 --> 00:44:26,130
there's a structure
right on the midline.

618
00:44:26,130 --> 00:44:27,890
It's called the septal area.

619
00:44:27,890 --> 00:44:30,225
And then below it,
the basal forebrain

620
00:44:30,225 --> 00:44:33,440
in front of the hypothalamus,
between the hypothalamus

621
00:44:33,440 --> 00:44:36,460
and the olfactory bulbs.

622
00:44:36,460 --> 00:44:41,300
We'll see that picture a number
of times in the next five

623
00:44:41,300 --> 00:44:42,750
classes.

624
00:44:42,750 --> 00:44:46,536
Then the hippocampal formation.

625
00:44:46,536 --> 00:44:48,214
We talked about
the medial pallium

626
00:44:48,214 --> 00:44:49,630
being important
to spatial memory,

627
00:44:49,630 --> 00:44:53,268
that it is part of
the limbic system.

628
00:44:53,268 --> 00:44:57,000
And there's a good reason
why it evolved that way.

629
00:44:57,000 --> 00:45:01,830
And then the amygdala which you
probably know very well by now.

630
00:45:01,830 --> 00:45:10,893
It's associated with pleasant
and unpleasant feelings

631
00:45:10,893 --> 00:45:13,080
towards things that we perceive.

632
00:45:13,080 --> 00:45:13,600
All right.

633
00:45:19,670 --> 00:45:23,682
So let's talk about
the hypothalamus here,

634
00:45:23,682 --> 00:45:29,290
and what it does
besides controlling

635
00:45:29,290 --> 00:45:32,151
the autonomic nervous system.

636
00:45:32,151 --> 00:45:36,270
It controls the endocrine
system by way of the pituitary.

637
00:45:36,270 --> 00:45:39,640
The pituitary is attached
to the hypothalamus.

638
00:45:39,640 --> 00:45:43,590
So how does the hypothalamus--
how do hypothalamic neurons

639
00:45:43,590 --> 00:45:49,870
control secretions from the two
major parts of the pituitary?

640
00:45:49,870 --> 00:45:52,690
One that's directly
[? between ?] part

641
00:45:52,690 --> 00:45:56,020
of the CNS, and one
that's a gland that's

642
00:45:56,020 --> 00:45:58,358
right next to the CNS.

643
00:45:58,358 --> 00:46:00,180
Those two parts
of the pituitary,

644
00:46:00,180 --> 00:46:03,140
they're called
anterior and posterior,

645
00:46:03,140 --> 00:46:05,430
because of how they're
placed in humans.

646
00:46:05,430 --> 00:46:08,220
In the rodent, the
posterior pituitary

647
00:46:08,220 --> 00:46:12,780
is above the
glandular pituitary.

648
00:46:12,780 --> 00:46:17,110
I've drawn it here from
studies, fairly recent studies,

649
00:46:17,110 --> 00:46:21,445
of the rodent, and
these are pictures

650
00:46:21,445 --> 00:46:28,860
that [? Nauda ?] did of these
structures in the human.

651
00:46:28,860 --> 00:46:31,740
OK, let's look at
the rodent here.

652
00:46:31,740 --> 00:46:38,240
You see the posterior
pituitary or neurohypophysis,

653
00:46:38,240 --> 00:46:43,870
that is the neural
part of the pituitary,

654
00:46:43,870 --> 00:46:46,550
receiving axons
from these two cell

655
00:46:46,550 --> 00:46:48,680
groups in the hypothalamus,
the ventricular

656
00:46:48,680 --> 00:46:50,610
nucleus, supraoptic nucleus.

657
00:46:53,600 --> 00:46:56,775
See the axon coming in.

658
00:46:56,775 --> 00:47:03,050
And those axons that are
ending in the neural pituitary,

659
00:47:03,050 --> 00:47:06,300
the neurohypophysis,
aren't ending on neurons.

660
00:47:06,300 --> 00:47:08,850
They're ending on blood vessels.

661
00:47:08,850 --> 00:47:13,370
So yes, they secrete
a transmitter,

662
00:47:13,370 --> 00:47:16,420
but the neurotransmitter
now enters blood vessels.

663
00:47:19,900 --> 00:47:24,356
It doesn't do that to distribute
throughout the body, though.

664
00:47:24,356 --> 00:47:27,250
I'm sorry, it does
that because it's

665
00:47:27,250 --> 00:47:29,640
a hormone distributed
throughout the body,

666
00:47:29,640 --> 00:47:31,510
and [INAUDIBLE] pituitary here.

667
00:47:34,620 --> 00:47:41,040
They come from these
neurons, both of them.

668
00:47:41,040 --> 00:47:43,185
They give rise to two hormones.

669
00:47:43,185 --> 00:47:46,900
Do you remember what they are?

670
00:47:46,900 --> 00:47:55,260
Oxytocin and ADH, which
means antidiuretic hormone.

671
00:47:55,260 --> 00:47:59,440
And what's the other name
for antidiuretic hormone?

672
00:47:59,440 --> 00:48:01,110
Vasopressin.

673
00:48:01,110 --> 00:48:07,139
OK, because it causes
vascular constriction

674
00:48:07,139 --> 00:48:08,556
and can affect blood pressure.

675
00:48:18,990 --> 00:48:21,160
An antidiuretic
hormone, of course,

676
00:48:21,160 --> 00:48:25,080
is involved in food retention.

677
00:48:25,080 --> 00:48:30,360
So if someone suffers a
tumor that's in this region,

678
00:48:30,360 --> 00:48:33,990
it affects the stalk
of the pituitary,

679
00:48:33,990 --> 00:48:40,505
and blocks these hormones so
they're no longer secreted

680
00:48:40,505 --> 00:48:47,480
into the bloodstream, a
person has a pathology

681
00:48:47,480 --> 00:48:51,460
called diabetes insipidus.

682
00:48:51,460 --> 00:48:56,780
It's called diabetes because
the symptoms are actually

683
00:48:56,780 --> 00:49:02,170
the same as the acute
onset of diabetes mellitus,

684
00:49:02,170 --> 00:49:07,760
and the person lacks the
ability to secrete insulin.

685
00:49:07,760 --> 00:49:12,870
Because when the person
can't secrete insulin,

686
00:49:12,870 --> 00:49:15,360
he uses different
metabolic pathways

687
00:49:15,360 --> 00:49:19,550
to get energy and get glucose
into the cells of the body

688
00:49:19,550 --> 00:49:21,830
because you need
insulin for that.

689
00:49:21,830 --> 00:49:23,655
So he uses other
metabolic pathways

690
00:49:23,655 --> 00:49:27,550
and starts metabolising
his muscle tissue.

691
00:49:27,550 --> 00:49:31,030
That produces ketone
bodies in the blood

692
00:49:31,030 --> 00:49:36,000
which raise blood acidity
and that can kill, of course,

693
00:49:36,000 --> 00:49:38,620
if it goes on too long.

694
00:49:38,620 --> 00:49:39,180
Sorry?

695
00:49:39,180 --> 00:49:41,210
AUDIENCE: [INAUDIBLE]

696
00:49:41,210 --> 00:49:43,470
PROFESSOR: The ketone
bodies are what

697
00:49:43,470 --> 00:49:51,230
cause the thirst to get so
high in acute onset diabetes.

698
00:49:51,230 --> 00:49:54,520
I experienced that for a
while, and I got diabetes.

699
00:49:54,520 --> 00:49:59,640
And I felt very thirsty and
was drinking a lot of fluid

700
00:49:59,640 --> 00:50:03,430
to basically get
rid of the acid.

701
00:50:03,430 --> 00:50:09,730
So you have the symptoms
of polyuria polydipsia.

702
00:50:09,730 --> 00:50:14,470
Polydipsia means drinking all
the time, thirsty all the time.

703
00:50:14,470 --> 00:50:17,490
Polyuria causes a lot of
urination, and, of course,

704
00:50:17,490 --> 00:50:19,872
you're getting rid of the acid.

705
00:50:19,872 --> 00:50:21,580
You're also getting
rid of a lot of sugar

706
00:50:21,580 --> 00:50:25,370
because the blood
sugar levels get high.

707
00:50:25,370 --> 00:50:30,120
Normally, ketoacidosis,
that effect,

708
00:50:30,120 --> 00:50:35,130
does not occur if I just
get high blood sugar today.

709
00:50:35,130 --> 00:50:38,970
It would take a long time and
a lot of insulin deficiency

710
00:50:38,970 --> 00:50:40,880
for me to develop
enough ketone bodies

711
00:50:40,880 --> 00:50:42,690
to cause that kind of problem.

712
00:50:42,690 --> 00:50:47,640
But that's what actually
kills in diabetes.

713
00:50:50,432 --> 00:50:51,890
Unfortunately, the
high blood sugar

714
00:50:51,890 --> 00:50:53,700
has a lot of other
bad effects too.

715
00:50:57,600 --> 00:51:00,630
All right, so we call
it diabetes insipidus

716
00:51:00,630 --> 00:51:04,566
because you get the same
symptoms, polyuria, polydipsia.

717
00:51:04,566 --> 00:51:08,890
But now it's because
of the lack of ADH, OK.

718
00:51:08,890 --> 00:51:12,400
They don't have normal
regulation of fluid levels.

719
00:51:15,310 --> 00:51:19,690
So people with that, just
like insulin diabetics

720
00:51:19,690 --> 00:51:23,215
need to be treated with insulin,
people with diabetes insipidus

721
00:51:23,215 --> 00:51:25,780
need to be treated
with these hormones.

722
00:51:25,780 --> 00:51:27,910
And, of course,
more importantly,

723
00:51:27,910 --> 00:51:31,040
you have to deal with the tumor.

724
00:51:31,040 --> 00:51:32,720
Sometimes they can
reverse the effects

725
00:51:32,720 --> 00:51:36,045
just by getting
the tumor removed.

726
00:51:36,045 --> 00:51:41,000
It's very difficult surgery
because of the location, OK.

727
00:51:41,000 --> 00:51:43,382
But surgeons have learned
ways to get at it.

728
00:51:43,382 --> 00:51:46,100
They can actually go through
the roof of the mouth

729
00:51:46,100 --> 00:51:48,440
to get at the
pituitary above it.

730
00:51:48,440 --> 00:51:51,600
All right, what about the
other part of the pituitary?

731
00:51:51,600 --> 00:51:54,610
I call it here the
adenohypophysis.

732
00:51:54,610 --> 00:51:57,494
Adeno means glandular tissue.

733
00:51:57,494 --> 00:51:58,410
OK.

734
00:51:58,410 --> 00:52:04,720
The glandular pituitary
or glandular hypophysis,

735
00:52:04,720 --> 00:52:10,990
it's also being the secretions
from the adenohypophysis,

736
00:52:10,990 --> 00:52:16,080
secretions like
the hormones that

737
00:52:16,080 --> 00:52:20,020
affect the gonads,
hormones that affect

738
00:52:20,020 --> 00:52:24,820
the adrenal glands, the
adrenocorticotropic hormone,

739
00:52:24,820 --> 00:52:26,540
OK.

740
00:52:26,540 --> 00:52:30,830
Gonadotropins,
they don't secrete

741
00:52:30,830 --> 00:52:33,340
directly testosterone
and estrogens.

742
00:52:33,340 --> 00:52:37,435
Those are secreted
peripherally by the testes

743
00:52:37,435 --> 00:52:40,360
and by the ovaries
primarily, and also

744
00:52:40,360 --> 00:52:44,410
somewhat by the adrenals, OK.

745
00:52:44,410 --> 00:52:47,930
But the hormones
from the hypophysis

746
00:52:47,930 --> 00:52:53,300
here, the adenohypophysis
stimulates those hormones.

747
00:52:53,300 --> 00:52:58,120
And their secretion is
affected by the hypothalamus

748
00:52:58,120 --> 00:53:02,140
from neurons like those here
in the median eminence region,

749
00:53:02,140 --> 00:53:07,220
this region of the hypothalamus,
the arcuate nucleus where

750
00:53:07,220 --> 00:53:11,480
I show you, here, cells
in that region with axons

751
00:53:11,480 --> 00:53:16,600
that are going in to
the proximal part, here,

752
00:53:16,600 --> 00:53:21,400
of the neurohypophysis and
also ending on blood vessels.

753
00:53:21,400 --> 00:53:24,920
But now they're ending
on blood vessels that

754
00:53:24,920 --> 00:53:29,620
enter this hypophyseal
artery, which

755
00:53:29,620 --> 00:53:33,420
then has many branches
into the adenohypophysis.

756
00:53:33,420 --> 00:53:37,210
Those factors, they're
called releasing factors,

757
00:53:37,210 --> 00:53:41,690
get to the adenohypophysis
also through a vascular system.

758
00:53:41,690 --> 00:53:46,175
We call it a portal system
because there are capillaries

759
00:53:46,175 --> 00:53:48,590
that pick them up,
and then they go

760
00:53:48,590 --> 00:53:53,700
to a larger vessel, a portal
vessel that gets them over

761
00:53:53,700 --> 00:53:55,765
to the adenohypophysis.

762
00:53:58,406 --> 00:54:03,460
Then you have another capillary
bed where they're released.

763
00:54:03,460 --> 00:54:06,300
And that's shown here in humans.

764
00:54:06,300 --> 00:54:11,200
He shows the vascular system,
sort of a cartoon of that here.

765
00:54:11,200 --> 00:54:15,680
So a capillary bed,
a portal vessel,

766
00:54:15,680 --> 00:54:19,600
and then another capillary bed.

767
00:54:19,600 --> 00:54:23,060
I tried to change it in
the text from portal vein

768
00:54:23,060 --> 00:54:24,590
to portal vessel,
because I thought

769
00:54:24,590 --> 00:54:25,965
there was a regent
who might want

770
00:54:25,965 --> 00:54:28,510
to call it a portal artery.

771
00:54:28,510 --> 00:54:33,300
But it's so traditional
to call it a portal vein

772
00:54:33,300 --> 00:54:39,260
that copy editor changed
it back to portal vein.

773
00:54:39,260 --> 00:54:42,270
So I did try to
correct the language.

774
00:54:42,270 --> 00:54:43,780
Ha-ha.

775
00:54:43,780 --> 00:54:45,640
But anyway, that's the
way the system works.

776
00:54:45,640 --> 00:54:47,300
It's important to
know and it's very

777
00:54:47,300 --> 00:54:49,270
important in understanding
human pathologies.

778
00:54:56,130 --> 00:54:58,120
So [INAUDIBLE] I
already mentioned,

779
00:54:58,120 --> 00:55:01,290
I think, the major
answer to question four,

780
00:55:01,290 --> 00:55:06,460
and I talked about question
five, diabetes insipidus.

781
00:55:06,460 --> 00:55:09,100
So what are the
homeostatic mechanisms

782
00:55:09,100 --> 00:55:12,146
associated with
the hypothalamus.

783
00:55:12,146 --> 00:55:14,340
Are we already way beyond time?

784
00:55:14,340 --> 00:55:17,560
I guess we are, so we
will stop, and we'll

785
00:55:17,560 --> 00:55:21,550
come back-- we're
finished right here,

786
00:55:21,550 --> 00:55:23,783
we'll come back to question six.

787
00:55:23,783 --> 00:55:27,030
And it shouldn't take
too long to review

788
00:55:27,030 --> 00:55:30,280
that if you've read
the chapter, OK.

789
00:55:30,280 --> 00:55:32,350
So then we'll continue
with the limbic system,

790
00:55:32,350 --> 00:55:35,830
and we'll begin talking
about connections

791
00:55:35,830 --> 00:55:42,560
between hypothalamus, some of
them by way of the thalamus,

792
00:55:42,560 --> 00:55:44,919
to the limbic system structures.