ANTERIOR HYPOTHALAMIC LESIONS 
What, then, are the essential details on which a theory of the 
neural mechanisms of temperature regulation must be based? The 
most important of these is that there is a separation of integrating 
areas for heat conservation from those regions essential for heat 
dissipation. This has been shown by two different types of prepar- 
ations, in the dog, Keller (1960) has established that it is possible 
for an animal to have minimal ability to withstand cold while having 
normal responses when exposed to a heat load. Our own original 
work andmy own recent work indicates that the other type of prepar- 
ation is also possible and we have been able to produce such animals. 
However the return of function in these cats poses more problems 
than it solves. Wliile we have good evidence for the localization 
of heat maintenance activities, the location or locations of these 
areas where heat loss activities are integrated are obscure. Cer- 
tainly the anterior hypothalamus must play some role but what the 
role is remains for the future to determine. 
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