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

Despite the obvious importance of temperature for brain functioning, it remains one of the least studied parameters of the brain. The 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. Using the method of laser speckle contrast imaging and micro-diamond thermometry, we performed a long-term simultaneous recording of blood flow velocity and temperature in the brain of anesthetized animals in vivo for the first time. To study the coupling between temperature and blood flow two approaches were used: enhancing the general blood flow by intraperitoneal injection of adrenaline and enhancing neuronal activity by applying KCl solution to the brain surface. The data we obtained indicated that the temperature of the nerve tissue had a more complex dynamics compared to blood flow, which was apparently associated with direct or indirect activation of both individual neurons and neural ensembles. Studies of temperature dynamics can make a significant contribution to understanding the nature of neurovascular coupling.