ROLE OF THE PROSENCEPHALON IN SHIVERING 
experiments a comparisonwas made ofthe alterations in respiration 
and heart rate produced by such stimulation. In two of these five 
experiments (Cats No. ST 13 and 17) limited posterior hypothalamic 
mapping was also undertaken. In two further experiments (Cats No. 
ST 18 and 24) the comparisons were not undertaken after extensive 
septal mapping, but rather the electrodes were oriented to septal 
loci when stimulation had produced somatic responses in previous 
experiments. 
Figure 13 lists the somatic responses evoked by septal stimula- 
tion in five cats. Planes A and B are schemata of typical cat brain 
frontal sections 16 mm (midseptum) and 14 mm (posterior septum) 
anterior to the interauricular line respectively. Loci 1, 2, 3 and 4 
and 9, 10, 11 and 12 are 1.5 mm from the midline while loci 5, 6, 7 
and 8 and 13, 14, 15 and 16 are 0.5 mm from the midline. Loci 1 and 
9 are 15 mm dorsal to the interauricular line, and loci 5 and 13, 
16 mm dorsal to this line. Loci ventral to these are at 2 mm depth 
intervals. As with the posterior hypothalamus, loci were stimulated 
at 1 mm depth intervals, but responses to stimulation of these loci 
are not listed for the previously mentioned reasons. Extensive 
mapping was undertaken at a frontal plane 15 mm rostral to the 
interauricular line, but responses to stimulation of these loci are 
not listed, since the responses at this plane were similar to those 
seen at Plane A. 
Only two somatic responses are listed, an increase in muscle 
tone and shivering. The table in Figure 13 indicates that shivering 
was observed in three of the five cats. The response was best 
evoked by stimulation of midseptal loci 1.5 mm lateral to the mid- 
line andfrom 13 mm to 9 mm dorsal to the interauricular line. Stim- 
ulation of loci 1 mm rostral to this region evoked an increase in 
muscle tone but not shivering. When shivering was observed it 
seemed of equal intensity and duration in limbs both ipsi and con- 
tralateral to the stimulated site. In these experiments this latter 
finding was based on both visual observation and EMG recordings. 
Table IX lists comparison of somatic, heart and respiration 
rate responses during stimulation of the most "active" septal loci 
and a posterior hypothalamic locus within the previously deter- 
mined region whose activation produces shivering. In the four cats 
(No.'s ST 5, 13, 18 and 24) in which shivering was not observed 
345 
