TEMPERATURE REGULATION "CENTERS" 
temperature changes; and as temperature changed either the amp- 
litude, the frequency, or the pattern of electrical activity of that site 
would change with temperature. So we placed our electrodes through- 
out the anterior hypothalamus and subsequently all through the basal 
forebrain in a search for electrical changes. We induced changes in 
temperature ranging from 28 C to 45 C and found no localized 
pattern of electrical change that we could relate to these temperature 
changes. Pathological changes we re, of course, frequently and widely 
manifest. 
Essentially, the result was zero. Something was wrongwith the 
experiment. We might have attributed it to anesthesia or to surgical 
trauma or to some other cause, but as it turned out, this was not 
the case. The fault lay in the fact that we had assumed that the cells 
under study were producing electrical activity that we could record 
with this method, and this turned out to be not so. 
Figure 1 shows a series of recordings taken from electrodes 
placed in the hypothalamus. The sets represent a horizontal section 
through the cat brain showing the lower pole of the caudate nucleus, 
cerebral peduncle and optic tract aroundthe anterior hypothalamus. 
There were five electrodes spaced 1.5 mmtoS.O mm apart, dorso- 
ventrally halfway between the optic chiasm and anterior comm issure . 
Each of these electrodes was recorded from with respect to one of 
two indifferent electrodes on the scalp, the top tracing showing the 
activity occurring between the reference points. There was a re- 
markable similarity between the records taken from these different 
points in the hypothalamus. We had anticipated that there might be 
some overlap of wave forms in different records from this region. 
We did not anticipate, however, the fact that these different records 
could be superimposed after appropriate adjustment of gain in the 
different channels, the only difference between them being that there 
was a gradient of amplitude from anterior to posterior. Only as far 
back as the level of the mammillary bodies (Fig. 1, C, 5G) or later- 
ally near the hippocampus was there introduction of other elements 
into the records, and there they were very difficult to see. But an- 
teriorly where we were particularly concerned with temperature 
changes, the entire region had one pattern of electrical activity. 
The recordings in Figure 1 were monopolar. We also tried 
bipolar recording to see whether or not the universal electrical 
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