HISTORICAL REVIEW 
Transections of the central nervous system. In locating centers 
within the central nervous system which are essential for function, 
one of the oldest procedures has been the central nervous system 
transection. Transections can be made at all levels in the central 
nervous system, excluding regions above or below the lesion from 
functional activity. Transections between the fourth cervical level 
and the lower medulla cannot be made without artificial respiration 
because of the failure of spontaneous respiration. In the classical 
work of Sherrington (1923-24), spinal cord transections were made 
in dogs and the animals were studied long after spinal shock had 
subsided. Sherrington found that shivering and cutaneous vasocon- 
striction failed in the cold in the structures innervated from the 
spinal cord below the lesion. 
When the cerebral cortex is removed by a brain transection 
just below the thalamus and the animals allowed to recover from 
the operation, there is no appreciable reduction in shivering. These 
observations, first made by Dusser de Barenne in 1920, have been 
confirmed by Pinkston, Bard, and Rioch (1934) and more recently 
by Birzis and Stuart at the University of Calif ornia. Bard and Rioch 
(1937) tound that ablation of the cerebral cortex resulted in a warm 
skin in a cool environment with more rapid onset of severe shiv- 
ering. This cutaneous vasodilation in a cool environment occurred 
after removal of the ansate cortex. In spite of a warm skin, the 
piloerection occurred. 
Whereas a brain transection removing the cerebral cortex 
from the brain stem has only a slight effect on temperature regu- 
lation against cold, a midbrain transection made between the dien- 
cephalon and mesencephalon (the decerebrate preparation) has a 
profound effect on temperature regulation. The decerebrate prep- 
aration is (for all practical purposes) poikilothermic, as shown by 
experiments of Bazett and Penfield (1922), Keller and Hare (1932), 
and Bard and Macht (1958). However, a few 'investigators jiave 
reported a sligjit residual tremor which can occur after transection 
in muscles innervated from levels of the central nervous system 
below the lesion. Dworkin (1930) found that shivering which was 
insufficient to prevent a fall in the rectal temperature of rabbits 
in the cold, occurred in medullary and midbrain preparations. 
Thauer and Peters (1937a and 1937b), using rabbits, found that after 
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