Mathematical treatment of the hypothalamic thermoregulatory system

A system was studied that consists of a controller, namely, the hypothalamic thermoregulatory center of the brain, and a controlled system, namely, the vasomotor system in the ear of the rabbit, which is under direct control of the hypothalamus. Biological data were collected on different characteristics of this system. The data were then treated mathematically, resulting in a mathematical description of the system that accurately and quantitatively describes its behaviour. The relationship between POAH (preoptic anterior hypothalamus) and ear pinnae temperature, which was found to have a straight-line character by G.N. McEween and J.E. Heath (1973), is modified to a segmoid relation. The segmoid description is more convenient physiologically, because it gives a sort of saturation for both maximum-heating and minimum-coolness processes.< >