ANTERIOR HYPOTHALAMIC LESIONS 
a perfect and perhaps a peculiar right to erect this strawman for, of 
the four papers alluded to, I am the senior author on two, the sole 
author on one, and was present in the laboratory when the experi- 
mental work on the fourth was done. This fourth paper (Magoun, 
Harrison, Brobeck, and Ranson, 1938) is a report on the partial ex- 
ploration of the hypothalamus with dual electrodes and an RF source 
of power. This use of a high frequency current for localized heating 
of the brain was a remarkable advancement in technique. Earlier 
workers (and some later ones) heated the carotid blood, heated the 
head, or used diathermic electrodes inserted into the subarachnoid 
space. With none of these techniques is it possible to exclude the 
heating of the great vessels at the base of the brain and with most of 
them it is not possible even to exclude the heating of the skin or mu- 
cous membranes. By using electrodes inserted into the brain and 
high frequency non- stimulating current, rather exact localization is 
possible for the sensing elements; such localized heating must be in 
the neurons or on the blood vessels in the brain. With threshold 
power Magoun and co-workers showed that a shift two mm in depth 
might alter markedly the response, which demonstrates the exact- 
ness of localization with this method. 
Figure 2 is a partial summary of their work. The location of 
active points — active in that localized heating at these points 
would result in panting — are projected onto a parasagittal section 
of a cat's brain. The most sensitive area — that with the lowest 
threshold — is an oval region ventral to the anterior commissure, 
dorsal to the optic chiasma and extending rostr ally into the preoptic 
region. Caudal from this active areais a region sensitive to heat but 
with a higher threshold than the rostral portion. The caudal limit of 
this less sensitive area is not indicated but it apparently reaches into 
the anterior mesencephalon. Unfortunately the method of reportmg — 
a method which migrated to the Southwest — gives only two dimen- 
sions. There are no indications ofthe lateral or medial limits of the 
area sensitive to heating, so anyone wishing to extend this work must 
repeat the original experiments before proceeding. It is hoped that 
this inadequate method of reporting will be discontinued. 
The other three papers are studies of the effects of various 
lesions on the thermoregulatory ability of cats. Figure 3 is a dia- 
gram of the lesion in one of these animals (Clark, Magoun, and 
Ranson, 1939). It is evident that the lesion is primarily in the lined 
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