Relationship between Temperature in the Deep Layers of the Somatosensory Cortex and Blood Flow Velocity in the Brain of Anesthetized Mice

Abstract

Despite the obvious importance of temperature in brain function, this parameter still remains insufficiently studied. Temperature is determined by the balance between the release of heat during metabolism and its removal by the bloodstream, which is regulated by neurovascular coupling. In this study, laser speckle contrast imaging and microdiamond thermometry were used for the first time to carry out a long-term simultaneous recording of blood flow velocity and temperature in the brain of anesthetized animals in vivo. To analyze the relationship between temperature and blood flow, two approaches were employed: the use of intraperitoneal adrenaline injection to increase blood flow rate and the application of KCl solution to the surface of the brain to enhance neuronal activity. The data obtained indicate that the temperature of nervous tissue has more complex dynamics when compared to that of blood flow; it is apparently due to the direct or indirect activation of individual neurons and neuronal ensembles. Studies that investigate temperature dynamics can make a significant contribution to the understanding of the mechanisms of neurovascular coupling.