Application of a digital deconvolution technique to brain temperature measurement and its correlation with other physiological parameters

The underlying reason for the local hyperthermia changes produced after a stimulus is not very well known and the relationship between local temperature changes and other physiological parameters has never been established. Current local temperature measurements are not completely accurate over time due to the physical constraints of the sensor, such as heat accumulation and dissipation. To clarify this issue, simultaneous in vivo measurements of local temperature, local blood-flow by laser Doppler flowmetry and neurotransmitter extracellular release using in vivo amperometry were performed with the aim of establishing their interrelationship. Local brain temperature measurements are usually obtained using thermocouples and thermistors, generally because of their small size and high level of accuracy. However, due to heat accumulation and dissipation effects on the sensor, the transient temperature measurement is not as accurate. In this paper, a simple method to obtain actual temperature fluctuations from measured values is proposed using classical digital signal processing techniques; the sensor was modeled via its transfer function. Deconvolution provides a method for obtaining actual temperature changes, enabling further comparative kinetic studies of all those physiological parameters, and helps to clarify the probable mechanism that underlies neurovascular coupling.