Different anesthesia regimes modulate the functional connectivity outcome in mice

Purpose: The use of resting-state functional MRI (rsfMRI) in preclinical research is expanding progressively, with the majority of resting-state imaging performed in anesthetized animals. Since anesthesia may change the physiology and, in particular, the neuronal activity of an animal considerably, it may also affect rsfMRI findings. Therefore, this study compared rsfMRI data from awake mice with rsfMRI results obtained from mice anesthetized with a-chloralose (120 mg/kg), urethane (2.5 g/kg), or isoflurane (1%). Methods: Functional connectivity (FC) was estimated using both independent component analysis (40 components) and ROI-based analysis to zoom in on the effect of different anesthetics on inter-hemispheric FC. Results: The data revealed an important diminishment of cortical interhemispheric FC in both the a-chloralose and urethane groups in comparison with the isoflurane and awake groups. Conclusion: When performing FC analysis in anesthetized mice, the impact of anesthetics must be taken into account. The required doses for stable anesthesia during MRI significantly decrease interhemispheric FC.