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118
IIA
ness, personality, and intelligcnce.
It
is primarily the
cerebral cortex.
Cerebral Cortex
The cerebral cortex is the thin -
average 1/6 inch - outermost !ayer
of the brain.
It
contains the cell bodies
of billions of nerve cells. Whenever
you view an exposed brain, everything
you actually see is this thin cerebral
cortex. It is convoluted ( folded and
furrowed) in order to compact a large
surface area into a small volume.
Scientists have differentiated two
general categories of cortex: One is
the
"specific
sensory projection
corlex,"
which receives, processes, and analyzes
the
direct
sensory information (visual,
auditory, tactile) comiog from the
outside world. The other is the
"in–
trimic corlex''
(
sometimes called
"unspecific" or "association" cortex),
which has
110
direct communication
with the externa! environment.
Intrinsic cortex can be split into
two distinct regions:
"posterior
intrin–
sic cortex," which is involved in
sensory associations and problem–
solving, and
"frontal
iotrinsic cortex,"
from which thinking
in
the sphere of
time, social awareness, and the "will"
originate. Jntrinsic cortex, then, is the
seat of the highest mental activities.
It is a key area for human thought.
PLAIN TRUTH May 1972
Man has a large cerebral cortex, ex–
tensive intrinsic areas, and a massive
frontal region. Consequently, it is
logícal that man is somewhat more
mentally advanced than mere brain
size suggests.
In fact, ít
is
the
relalive
proportion
of intrinsic cortex which is critica!.
Too much specific
cortex "clutters up"
the brain - much as numerous local
radio stations will limit the range of
a superpower station - thereby not
allowing the intrinsic cortical areas
the "uojammed freedom" necessary
for the generation of cognitive, sym–
bolic, and abstract thought.
So
it
is the
ratio
(percentage) of
íntrinsic cortex to total cortex (as well
as the total
amo11111
of intrinsic cortex)
which is crucial. This percentage is
roughly 10% in rat, 50% in cat, 75%
in monkey, and 95% in man. Recent
data indicates that the percentages of
intrinsic cortex in whale and dolphin
are roughly the same as in monkey.
Thís means that whalc and dolphin
have a
greater
rJm011111
of intrinsic
cortex than man, with very dose to
the same ratio. How then could man's
small advantage in ratio more than
offset his considerable disadvantage in
amount?
Professor Slijper reports that ceta–
cean (whalc, dolphin, porpoise) brain,
aside from its size, is remarkably simi–
lar to the human brain. He emphasizes
that cetacean cerebral cortex is excep–
tionally convoluted (just like the
human brain) and extends so far back
that in the common dolphín it com–
pletely covers the cerebellum at the
rear of the cranial cavity (again,
j11Jt
like the human brain). Slijper con–
tends "these convolutions are not only
very striking in appearance, but are
an essential criterion for judging the
stage of development a given brain
has reached." He surns up bis impres–
sions by facetiously asking: "Must we
assurne that porpoises, Sperm Whales
and dolphins, by virtue of their highly
developed brains have the capacity akin
to those of man ... ?" Brain capacity
-
)'es.
1
Mental capacity -
110.
And
that's the point.
Cetacean Cerebral Cortex
Perhaps the most knowledgeable
assessment of the cetacean brain comes
from Lawrence Kruger's chapter in
Wh(/les, DoJphins and Porpoises
(edited by Norris). Kruger immedi-
1
Somo
<ntcrpnsin~t
youn¡: scholar will probably
quotc Towcr'
s
1911 papcr in an •tt<mpt to pro
ve
that.
althou~th
thc cet.c<an brain
is
l2rger th•n
th< human brain. lt<
dt11Jit¡
of cerebro·cortlcal
n<urons is
sl~nlficantly
I<SS. And thcr<forc the
txtremcly inferior mental out¡>ut of cetactans as
compartd to humans is
phyJtrally
exploin<d.
But look JI the facts.
As • )1<ncul rulo. as the cerebral cortex in·
crc.ts~s
in
sü:t
in difTerent nnimals,
tht
neuron11l
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