ABSTRACT
This preliminary study describes a noninvasive, inexpensive approach to the study of lateralization as related to mental activity. It supports the concept of a thermoregulatory role of blood in cerebral temperature control. Right and left angularis oculi vein temperatures were measured during periods of mental activity and mental rest and both temperature changes were asymmetrical. There was a consistent temperature drop during thinking, with a consistent rise after thinking ceased. Heat loss from superficial vessels of the buccal region and nasal mucosa to the ambient air was evident which caused lowering of the venous blood temperature flowing towards the cavernous sinus. This drop in blood temperature of angularis oculi veins coincided with increased brain metabolism and heat production occasioned by an increase in the level of mental activity and oxygen utilization.