The cerebral cortex and limbic system

Functional roles for parts of the cerebral cortex in the control of autonomic nervous system activity have been suspected and partially demonstrated for several decades. Fulton (1949) describes autonomic representation in the pre-central motor cortex. Newman & Wolstencroft (1960) found that heating the blood flowing in the carotid arteries to about 41 °C caused a fall in arterial blood pressure, presumably associated with peripheral vasodilatation, and that stimulation of the posterior orbital cortex prevented the fall in blood pressure. Ström (1950) reported that electrical stimulation of the frontal cortex and also the hypothalamus elicited peripheral vasoconstriction in dogs, cats and rabbits, but frontal decortication did not abolish the vasoconstriction consequent on hypothalamic stimulation implying that the hypothalamically induced vasoconstriction did not depend on a cortical pathway. Eliasson & Ström (1950) located the cortical vasoconstrictor region to a region close to the cruciate sulcus and in the white matter of the frontal lobe. A full discussion of the association of various cortical areas with autonomic function has been published by Cechetto & Saper (1990). Dogs which are decorticated have impaired body temperature regulation in both hot and cold environments (Pinkston et al., 1934; Delgado & Livingstone, 1948). A method for functional decortication is the induction of CSD by flooding an area of the cerebral cortex with high molarity K+ solution. This has been shown to alter thermoregulatory functions in rats (Shibata et al, 1983, 1984, 1985).