ABRAMS, ROBERT, AND H. T. HAMMEL. Cyclic variations in hypothalamic temperature in unanesthetised rats. Am. J. Physiol. 208(4): 698-702. 1965. -Male and female rats, equipped with stainless steel re-entrant tubes implanted in the brain adjacent to one preoptic area, were placed in cages with accessible activity wheels. Brain temperatures were recorded continuously for periods up to 48 hr by mea...