KAWAMURA, Y. 
DR. KAWAMURA: This would be an interesting problem. 
DR. JOHANSEN: I was thinking that you mi^t try artificial 
respiration and attempt to interfere with the phases of the respir- 
ation, in order to exclude, for instance, the stretch receptors. 
DR. KAWAMURA: I have made a study of the relationship of j 
artificial respiration and shivering. Through my experience I can 
tell you that shivering movement is always followed by the inspira- 
tory phase, under fast or slow rhythm of artificial respiration. 
DR. FREEMAN: We found the same relationship between shiv- 
ering and inspiration when we were recording unit activity in the 
brain stem associated with the shivering. These unit potentials come 
with shivering and go when shivering stops, but during the early 
part when shivering is phasic with inspiration these bursts are 
synchronous with inspiration. Also, your observation of a painful 
stimulus is true of these units as well. There are many units in the 
nervous system which can be drivenby painful stimuli. Their activ- 
ity can be either started or increased and there are relatively few 
that will be inhibited; but these shivering unit potentials are very 
strikingly shut off, and when the painful stimulus is removed, there 
is a striking rebound phenomenon. Their frequency increases abrupt- 
ly above the preceding level. 
DR. HENSEL: Have you any observation of the topography of 
shivering in the proximal and distal parts of the limb ? We found 
in our investigations in the cold chamber that shivering starts in 
the proximal parts of the limbs as measured by the EMG. After pro- 
longed cold exposure, then the increased muscular tone in the prox- 
imal parts will disappear, and increased tone in the distal parts 
appears; so there is a temporal shift in the topography of shivering. 
DR. KAWAMURA: Yes, I believe there is a problem, and I vis- 
ually recognized that usually the peripheral region begins shivering 
earlier than the proximal vibration appears, but no exact recordings 
were made on the proximal and distal distribution of shivering. 
DR. FREEMAN:If you asphyxiate an animal or impair his res- 
piration, then instead of having simply the intercostal muscles and 
220 
