Selective Brain Cooling during Fever ?

Abstract

Selective brain cooling (SBC) is a mechanism, by which many mammalian species can cool their brains below the temperature of the arterial blood (Tblood). In these species, arterial blood destined for the brain passes the carotid rete where it is cooled by venous blood draining the nasal mucosa (1). SBC occurs during normothermia and hyperthermia, increases with carotid blood temperature, is in principle independent of panting, and causes a dissociation of brain temperature (Tbrain) and Tblood (2). SBC is controlled by the venous return from the nasal mucosa which can be directed either via the angularis oculi vein to cause SBC, or via the facial vein to flow directly back to the trunk without SBC (3). SBC is regarded as a mechanism to protect the brain against heat damage. Fever is a condition during which Tblood rises significantly and the thermoregulatory thresholds for heat loss are elevated. If the protection against heat damage is the main function of SBC, it should be fully active during fever.