ROLE OF THE PROSENCEPHALON IN SHIVERING 
The responses evoked after bilateral fornical destruction were 
relatively similar to those evoked in cats which the precommissural 
fornical fibers were intact. Similarly the responses evoked in Cat 
No. ST 31 were relatively similar for both sides of the brain, even 
though the right side septum contained degenerated precommissural 
fornical fibers. Figures 22 and 23 illustrate these facts. 
a 
Figure 22 illustrates an experiment on Cat No. ST 29 .In this 
cat an attempt was made to destroy the fornix one week prior to 
experimentation. The upper right-hand corner photographs illustrate 
partial left fornix destruction at a slightly more rostral level than 
more complete right fornix destruction. Loci were stimulated each 
fifth minute in the order A, B, C, D, and E with stimuli of frequency 
25 pulses/sec, 1 msec pulse duration and 300 m A/pulse. As shown, 
shivering was not suppressed by stimulation of loci D and E, mildly 
suppressed by stimulation of loci A and B, and strongly suppressed 
by stimulation of locus C. 
Figure 23 illustrates partial right fornical destruction in Cat 
No. ST 31. As shown, stimulation of locus A evoked mild suppression 
of shivering during left side but not right side stimulation. Stimula- 
tion of the more ventrally situated locus B evoked suppression of 
shivering during both right and left side stimulation. The parameters 
of stimulation for these responses were a frequency of 25 pulse/sec 
or pulse duration of 1msec and a stimulus intensity of 800 m A/pulse. 
In the above-mentioned experiments the frequency of stimulation 
ranges from 25 to 100 pulses/sec and the pulse duration from 1 to 3 
msec. In four experiments the minimum of stimulus intensities 
necessary to evoke both strong and mild suppression of shivering at 
a variety of frequencies and pulse durations were noted. Figure 24 
is a schematic representation of the effects of alterations in pulse 
duration on the intensity of stimulation necessary to suppress 
a 
shivering in Cats No. ST 32 and 34. The stimulus frequency was 
maintained at 25 pulses/sec. Less intense stimuli were necessary 
to evoke suppression of shivering at pulse durations of 3 and 5 msec 
than at 0.5, 1, and 7 msec in both cats. In Cat No. ST 34 this ap- 
peared true for both septal and anterior hypothalamic suppression 
of shivering, although not so detailed observations were made during 
septal stimulation. However, the intensity of stimulation necessary 
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