HISTORICAL REVIEW 
and its possible relation with the posterior hypothalamus will be 
discussed in the work of Stuart later in this Symposium, Shivering 
cannot only be induced by electrical stimulation of points in the 
brain but it can be suppressed, if it has started spontaneously by 
cold, by stimulation of other points. Kaada (1951) was able to inhibit 
shivering by electrical stimulation of points on the cerebral cortex 
while Hemingway, Forgrave, and Birz is (1954) found that spontaneous 
shivering could be stopped or attentuated by electrical stimulation 
of points widely distributed in the hypothalamus. A particularly 
active suppression region as determined by low stimulus threshhold 
was found in the pre-optic region. 
Electrical stimulationof various points in the brain has revealed 
that shivering can be started or, it preceding spontaneously, stopped 
by electrical stimulation of points within the brain. The points for 
shivering suppression are more widely distributed than the points 
for shivering stimulation. The most active point for suppression is 
found in the pre-optic region, while the most active point for stimu- 
lation, as Stuart will report later, isinthe posterior hypothalamus. 
Other points of higher threshold for both suppression and stimulation 
can be found throughout the brain. 
At the present time, only a tentative "working" hypothesis of 
the control of shivering in the cat can be made resulting from inter- 
pretation of the stimulation experiments. The active region in the 
posterior hypothalamus for stimulation may be a primary center for 
starting and control of shivering, but its function may be under sub- 
sidiary influence of secondary centers, particularly in, or rostral 
to, the feline septum . The widely distributed suppression effects may 
be interpreted as due to the existence of an inhibitory mechanism 
for shivering. Shivering, if not too intense, can be suppressed volun- 
tarily, which may involve the cortical suppression control of Kaada. 
Shivering is also inhibited by voluntary movement. When a voluntary 
movement is made by a limb, shivering ceases. It seems that in the 
control of the skeletal musculature, shivering is a function of oecon- 
dary importance to locomotion. This is reasonable in consideration 
of animal safety and maintenance that first priority should be as- 
signed to movement for flight, fight, and defense. When the skeletal 
musculature is needed for these life-saving functions, shivering 
can be temporarily suspended in favor of emergency action. This 
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