Related Experiment Video
Updated: May 5, 2026
Real-Time fMRI Brain Mapping in Animals
Published on: September 24, 2020
Different anesthesia regimes modulate the functional connectivity outcome in mice
Elisabeth Jonckers1, Rafael Delgado y Palacios, Disha Shah
1Bio-Imaging Lab, Antwerp, Belgium.
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 α-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 α-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.
Insights
Anesthesia significantly reduces interhemispheric functional connectivity (FC) in mice during resting-state functional MRI (rsfMRI) scans. Researchers recommend considering anesthetic impact for accurate preclinical rsfMRI findings.
Area of Science:
- Neuroscience
- Medical Imaging
- Preclinical Research
Background:
- Resting-state functional MRI (rsfMRI) is increasingly used in preclinical research.
- Most rsfMRI studies are conducted on anesthetized animals.
- Anesthesia can alter physiological and neuronal activity, potentially affecting rsfMRI results.
Purpose of the Study:
- To compare rsfMRI data from awake mice with data from mice anesthetized with α-chloralose, urethane, or isoflurane.
- To investigate the impact of different anesthetics on functional connectivity (FC) in mice.
Main Methods:
- rsfMRI data acquired from awake mice and mice under three different anesthetic regimens.
- Functional connectivity (FC) analyzed using independent component analysis and ROI-based analysis.
- Focus on inter-hemispheric FC to assess anesthetic effects.
Main Results:
- Cortical interhemispheric FC was significantly diminished in mice anesthetized with α-chloralose and urethane.
- The isoflurane and awake groups showed higher interhemispheric FC compared to α-chloralose and urethane groups.
- Anesthesia dose impacts FC, with stable anesthesia doses reducing interhemispheric FC.
Conclusions:
- The choice of anesthetic agent and its dosage significantly influences rsfMRI findings in mice.
- Anesthetics, particularly at doses required for stable anesthesia, markedly decrease interhemispheric FC.
- Researchers must account for anesthetic effects when interpreting preclinical rsfMRI data.
