Hyperthermia-Induced Changes in EEG of Anesthetized Mice Subjected to Passive Heat Exposure

Abstract

Currently, the role of hypothermia in electroencephalography (EEG) is well-established. However, few studies have investigated the effect of hyperthermia on EEG, an important physiological parameter governing brain function. The aim of this work was to determine how neuronal activity in anesthetized mice is affected when the temperature rises above the physiological threshold mandatory to maintain the normal body functions. In this study, a temperature-elevation protocol, from 37 to 42°C, was applied to four female mice of 2–3 months old while EEG was recorded simultaneously. We found that hyperthermia reduces EEG amplitude by 4.36% when rising from 37 to 38 degrees and by 24.33% when it is increased to 42 degrees. Likewise, increasing the body temperature produces a very large impact on the EEG spectral parameters, reducing the frequency power at the delta, theta, alpha, and beta bands. Our results show that hyperthermia has a global effect on the EEG, being able to change the electrical activity of the brain.

Elevating understanding: Linking high-altitude hypoxia to brain aging through EEG functional connectivity and spectral analyses

“…Our study has some limitations that constrain the impact of these findings: Firstly, the influence of high altitude on the EEG functional connectivity could comprise not only the reduction of the oxygen pressure by altitude, but also changes in environmental variables. For example, external temperature may affect EEG spectral properties ( de Labra et al, 2021 ; Gaenshirt et al, 1954 ; Pearcy & Virtue, 1959 ). Our results must be contrasted by conditions in which environmental variables can be controlled, as usually done when simulating hypobaric hypoxia.…”

Interindividual variation of the organism - as an indicator for assessing the severity of heat stroke in an experimental study of Wistar rats

“…The study was processed as a prospective experimental, randomized study based on the albino Wistar rat model of hyperthermia. The research was conducted at the Medical faculty of the University of Sarajevo, in accordance with the Principles for the Care of Laboratory Animals (11). After the approval of the Ethics Committee of the Faculty of Medicine of the University of Sarajevo (registration number 02-3-4-1253/20, Bosnia and Herzegovina), the total number of adult Wistar rats, body weight from 200 to 300 g, were included in experiment.Target temperature points in the water bath were determined and one rat at a time was exposed to a total of 40 rats included in the experiment.…”

Interindividual variation of the organism - as an indicator for assessing the severity of heat stroke in an experimental study of Wistar rats

“…The research was conducted at the Medical faculty of the University of Sarajevo. All experiments were performed in compliance with the regulations of Principles for the Care of Laboratory Animals (11). After the approval of the Ethics Committee of the Faculty of Medicine of the University of Sarajevo (registration number 02-3-4-1253/20, Bosnia and Herzegovina), the total number of adult Wistar rats, with body weight from 200 to 300 g, were included in the experiment.…”