TEMPERATURE REGULATION "CENTERS" 
becomes irregular and spasmodic when the cerebellum is removed. 
I might also mention the contribution of the reticular formation 
to shivering, since this is another region which is involved in 
shivering, but not specific for it; however, time does not permit to 
go into it in any detail. The anterior hypothalamus is another sen- 
sory mechanism, which Dr. Lim and Dr. Hensel have shown to be 
clearly implicated in the shivering process. It is probably not 
essential for it to occur, and certainly there are other things that 
the anterior hypothalamus regulates besides shivering. One might 
now ask, what aboutthenucleusof Forel?ls it involved in shivering, 
as suggested by unit activity, or is it not involved, as the results of 
the lesions would imply? During the process of shivering there is 
muscular vasodilation, perhaps active. There is an increase in 
cardiac output, an increase in rate and depth of respiration, all 
subserving an increase in oxygen consumption and transport. Does 
this discharge that we see, which is related to shivering, subserve 
merely the skeletal muscular contraction, or does it subserve the 
entire autonomic- somatic pattern associated with shivering? 
The nucleus of Forel receives a powerful descending projection 
from the corpora striata, so that a large proportion of the entire 
efferent outflow of the basal ganglia passes through this nucleus. 
It would be rash to assume that other patterns of activity related to 
other forms of behavior are not partially organized in the nucleus 
of Forel. Is thereapatternof cellular activity specific for shivering 
and another pattern specific for each other form of behavior, or is 
there a common pattern to all these activities? If this structure is 
stimulated electrically, will it reproduce the pattern for shivering, 
or will it give something else, some entity which is not related to 
any observable phenomenon in the nervous system? If stimulation 
is applied in a situation in which some other rhythmic process is 
occurring, such as chewing, rutting during sexual behavior, or 
panting, will shivering occur or some other rhythmic contractile 
process? 
These considerations are summarized in diagrammatic form 
in Figure 11, showing a sketch of a longitudinal section of the cat 
brain. It is proposed that each of the structures indicated is active 
during shivering, and that each contributes some analytical element 
283 
