Evening star., 1950-09-18
Psychologists Study1,..2
Double Mature of Bruin
CerebelIum Is Found to Respond
To Stimuli as Cerebrum Does
BY Thomas R. Henry

ny lnomoS \. nenIy
Man has a double brain ~
The deeply buried cerebellum-or Tit
tie brain"-appears to duplicate precisely
the cerebrum, or big brain which pre-
viously had been regarded as the or
gan of all thought, sensation and con-
SciouSneSs.
This finding by a group Of physiolo-
gists working at Northwestern Univer-
sity, Evanston, ILL.,, under Office of Naval
Research grants, promises to be one of
the most significant advances yet made
in understanding of brain mechanisms.
The work has been in progress for the
past five years. DR.. Ray S. Snider has
just made the first comprehensive re-
port to the Navy on the results already
achieved a.
The functions of parts of the cere-
brum, or top of the brain, are we'll known.
There is, for example, the so-called motor
area, thin strip Of grey cells just back
of the forehead. When any part of
this is stimulated by electricity, some
part of the body will move. Stimula-
tion in one place will move the little
finger of the left hand, in another place
the thumb, in another place one Of the
big toes. Actually it is very much finer
than this. Stimulation at different
places will move successfully the first,
second and third joints of the little
finger. The same precision is found in
the temporal lobeS back of the ears,
which are sensitive to sound, and the
occipital lobe at the back of the skull,
which regulates seeing precisely for ex-
tremely slight variations of color, hue,
and the like.
Man Lived without It.
Up to now the cerebellum, the second
largest part of the brain, has been mis-
understood. 1t has been credited with
few associations with the cerebrum and
no part in sensation. 1t is described in
most textbooks as a balancing organ
Relatively, it is much larger in birds
than in mammals, which have less need
to preserve precise balance. The human
cerebellum, in fact, has not been con-
sidered of very great Importance. At
st. Elizabeths Hospital there Is pre-
served in alcohol the brain of a man
who was born without a cerebellum and
seemed to have suffered no noticeable
disadvantage from the fact. True, he
died in hospital for the insane, but
there was no possible connection between
his mental condition and the lack of the
large top part of the brain. s.
This situation had seemed anomalous
to brain researchers for years when the
Navy group undertook their studies.
They have worked with higher animals
but their findings unquestionably extend
to man.
First they found conclusive evidence
that the cerebellum received, just as
10 TO
movements of fingers, toes and the like
and that when appropriate points were
stimulated by electricity these organs
could be caused to move involuntarily.
There was motor area which was just
as precise as that of the big brain. In
fact, it seemed to correspond, point by
point, with the cerebral motor area.
This finding now has been extended,
DR.. Snider reports, to the auditory and
sight areas These are far apart on the
surface of the cerebrum. They seem to
overlap on the surface of the cerebellum.
Nerve Pathways Complex.
Evidence being assembled now, in
dicateS that every senSory impulse re-
ceived by the cerebrum is transmitted
by somewhat complex pathways Of nerve
f1bers to corresponding areas on, the
surface of the cerebellum They then are
transmitted back again. 1t is becoming
more and more probable that there is
exact duplication all along the line. The
cerebellum apparently does everything
the cerebrum does, except actually think.
The purpose of all this remains OBJ
Scure. 1t is highly unlikely that nature
would allow so much purposeless shut
tling. Yet the Navy researchers can find
no evidence that the little brain plays
any part Whatsoever in consciousness.
They have demonstrated that impulses
sent back to the cerebrum from the cere-
bellum can modify considerably the
physical reactions set up by the top of
the brain. They can make finger, for
example, twitch either more or less vio-
lently, dependent on factors which re-
main unknown. .Es
The hitherto obscure cerebellum is
described as probably 'the great modu-
lator of nerve function" 1t acts both as
a curb and spur to the big brain, which
it seems exactly to duplicate. What
regulates the cerebellum itself remains
unknown, since it is far removed from
contact with the outside world and in
formation as to the needs of the indi-
vidual.
A curious fact about this obscure part
Of the brain reported by Dr. Snider is
the swiftness of it's brain waves" rang
ing between 800 and 400 second.