TEMPERATURE REGULATION "CENTERS" 
TIME 
mm 
I mu ll* liMw H iii 
MiMiMi^^ 
20 
min 
iiiWiiiiiiiiiii 
mm 
ze mmmmmmmmmmmmm 
min 
45 mmtimmmiiimiiMtmtmm 
iiiiiiiBliiiiiiiliiiiiiiiiliiiMiH 
iiilSiM 
55 
min g^|^g^,|gi,^,,g^g||jg|,yigy^lgg|laM^^ 
Figure 8. These tracings illustrate the procedures used to 
establish the association of a unit potential with shivering. The upper 
tracing of each pair is a continuous record from a microelectrode; 
the lower tracing is a concomitant electromyogram. At the right 
are tracings of the unit discharge as observed by triggering the 
sweep drive on an oscilloscope with the positive phase o^ the spike 
(cf. Fig. 3). Only the relatively long-lasting negative wave of the 
spike was reproducible in the records at the left. At min a unit 
discharge was located and emptying of the cold water bath was be- 
gun. At 6 min the changeover to warm water was complete. At 20 
min both shivering and unit were disappearing. Changing the bath 
to cold water brought an almost immediate reappearance of both the 
spike and of shivering; re-immersionin warm water again suppres- 
sed both. The change to a third cold bath did not produce an immedi- 
ate effect, but 3 min after complete cold immersion both shivering 
and the unit reappeared, and thereafter both rapidly increased in 
intensity. The close similarity of the 3 wave forms at the right in- 
dicates that the same unit was re-activated with each cold immer- 
sion. Time: left, 1.0 sec; right, 1.0 msec 
275 
