TEMPERATURE REGULATION "CENTERS" 
activity was masking local changes which might best be picked up 
by two electrodes as close together as 0.5 mm. The amplitude was 
clearly much less (Fig, 2) than that from either with respect to a 
distant electrode, but there was no other difference. This was also 
true for tipseparationsof 1.5mm,3.0mm, and 6.0 mm, the records 
from which were nearly identical except in aunplitude. There was 
no disclosure of any other signal than that recorded with monopolar 
electrodes, implying that the hypothalmus had a uniform electrical 
activity underthe conditions of this experiment, which did not involve 
evoked transients or abnormal temporal synchrony. This identity 
of pattern was true not only of the hypothalamus proper, but also 
of much of the surrounding region, i.e., inferior pole of the caudate 
nucleus, the olfactory striatum, parts of the septum and the cerebral 
peduncle. 
We attempted by diathermic heating locally in the hypothalamus 
to elicit local changes in the hypothalamic electrical pattern. There 
were four electrodes in this experiment with monopolar recording 
from each; the diathermy current was passed between the outer 
two, there being a thermocouple centered between the middle pair 
of electrodes for control of the hypothalamic temperature. The 
middle pair permitted study of the electrical activity without having 
to use theheatingelectrodes, around which the tissue was destroyed. 
Figure 3B shows that after heating to a temperature of 50 C, which 
is quite high for hypothalamic temperature, not only was the elec- 
trical activity from the intervening electrodes substantially unal- 
tered but so also was the electrical activity recorded from genera- 
ting electrodes. There was some difference in wave form, which was 
of the type which was seento occur spontaneously during the course 
of an experiment and did not represent a significant change. 
o 
In Figure 3C, the interveningthermocouple was heated to 70 C, 
almost, one mig^t say, the boiling point of the brain, and there was 
substantially no change in subsequent records. Histologically at 
post-mortem there was coagulative necrosis of the hypothalamus, 
parts of the septum, the caudate nucleus, and the thalamus. We did 
find a way of abolishing this activity, and that was to make transec- 
tions of the brain ventrolateral to the hypothalamus. Transections 
could be made anteriorly, laterally, dorsally, and posteriorly (Fig. 
3F) with little change as long as the medial forebrain bundle was 
263 
