ROLE OF THE PROSENCEPHALON IN SHIVERING 
2 
electrode R , shown in the lower lefthand sketch of Figure 16. This 
region is the most rostrolateral aspect of the dor somedial region of 
the posterior hypothalamus. Activation of a contralateral region 
about 1 mm more rostral during stimulation via electrode L never 
produced shivering. Stimulation of two ventrolateral posterior 
hypothalamic regions shown in the lower righthand sketch never 
produced shivering. 
In Cat No. IM 6, activation of the dorsal midseptal region, 
indicated by electrode 2 in the top lefthand figure , produced shiver- 
ing. At this midseptal level, shivering was not produced by stimula- 
tion of a ventromedial region (electrode 1, top lefthand sketch), and 
at the posterior septal level, shivering was not produced by stimu- 
lation of a dor somedial locus (electrode 3 in the top righthand 
sketch). At the posterior hypothalamic level, shivering was produced 
by stimulation of the dor somedial region (electrode 4 in the bottom 
lefthand sketch), and in the rostral midbrain it was produced by 
dorsomedial activation (electrode 5 in the bottom righthand sketch). 
These results for unanesthetized preparations confirm the re- 
sults for anesthetized preparations with respect to the localization 
of regions whose activation produces shivering. Such confirmation 
was considered a necessary part of this study in order to negate 
the possiblility that the shivering responses seen during the anes- 
thetized preparation studies were not peculiar to the use of alpha 
chloralose or pentobarbital sodium. 
On the other hand, the results add no information regarding the 
relative sensitivity of septal and posterior hypothalamic loci with 
respect to the production of shivering. In all cases shivering was 
produced in the unanesthetizedcats with stimuli of intensity 800 iih/ 
pulse and not produced with stimuli of intensity 400 ju A/pulse. 
However, stimuli of interim intensity were not delivered. Secondly, 
nothing is known of the latency of the response because the presence 
or absence of shivering was noted by visual inspection and by pal- 
pation. At the moment the stimuli were applied, the door of the 
Faraday cage was closed. It was only opened after the investigator 
was reasonably sure it was safe to palpate the cat. 
During stimulation of these loci, many sympathetically and 
parasympathetically mediated responses were observed. They 
357 
