Related Experiment Video
Updated: Apr 25, 2026
Acquisition of Resting-State Functional Magnetic Resonance Imaging Data in the Rat
Published on: August 28, 2021
Optimization of anesthesia protocol for resting-state fMRI in mice based on differential effects of anesthetics on
Joanes Grandjean1, Aileen Schroeter1, Imene Batata2
1Institute for Biomedical Engineering, University and ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, Winterthurer-Str. 190, 8057 Zurich, Switzerland.
Abstract:
Resting state-fMRI (rs-fMRI) in mice allows studying mechanisms underlying functional connectivity (FC) as well as alterations of FC occurring in murine models of neurological diseases. Mouse fMRI experiments are typically carried out under anesthesia to minimize animal movement and potential distress during examination. Yet, anesthesia inevitably affects FC patterns. Such effects have to be understood for proper interpretation of data. We have compared the influence of four commonly used anesthetics on rs-fMRI. Rs-fMRI data acquired under isoflurane, propofol, and urethane presented similar patterns when accounting for anesthesia depth. FC maps displayed bilateral correlation with respect to cortical seeds, but no significant inter-hemispheric striatal connectivity. In contrast, for medetomidine, we detected bilateral striatal but compromised inter-hemispheric cortical connectivity. The spatiotemporal patterns of the rs-fMRI signal have been rationalized considering anesthesia depth and pharmacodynamic properties of the anesthetics. Our results bridge the results from different studies from the burgeoning field of mouse rs-fMRI and offer a framework for understanding the influences of anesthetics on FC patterns. Utilizing this information, we suggest the combined use of medetomidine and isoflurane representing the two proposed classes of anesthetics; the combination of low doses of the two anesthetics retained strong correlations both within cortical and subcortical structures, without the potential seizure-inducing effects of medetomidine, rendering this regimen an attractive anesthesia for rs-fMRI in mice.
Insights
Anesthesia profoundly impacts resting-state fMRI (rs-fMRI) in mice. Comparing four anesthetics revealed distinct functional connectivity (FC) patterns, guiding optimal anesthesia choices for neurological disease research.
Area of Science:
- Neuroscience
- Neuroimaging
- Pharmacology
Background:
- Resting-state fMRI (rs-fMRI) in mice is crucial for understanding functional connectivity (FC) and neurological disease models.
- Anesthesia is necessary for mouse fMRI but significantly alters FC patterns, necessitating careful consideration for data interpretation.
Purpose of the Study:
- To compare the influence of four common anesthetics (isoflurane, propofol, urethane, medetomidine) on rs-fMRI functional connectivity in mice.
- To establish a framework for understanding anesthetic effects on rs-fMRI and guide optimal anesthesia selection for mouse studies.
Main Methods:
- Acquisition and analysis of rs-fMRI data from mice under four different anesthetic regimens.
- Comparison of functional connectivity patterns, including cortical and striatal connectivity, across anesthetics.
- Correlation of observed FC patterns with anesthesia depth and anesthetic pharmacodynamics.
Main Results:
- Isoflurane, propofol, and urethane produced similar FC patterns, characterized by bilateral cortical correlation and absent inter-hemispheric striatal connectivity.
- Medetomidine resulted in bilateral striatal connectivity but compromised inter-hemispheric cortical connectivity.
- Anesthesia depth and pharmacodynamic properties were rationalized to explain observed spatiotemporal rs-fMRI signal patterns.
Conclusions:
- Anesthetic choice significantly influences mouse rs-fMRI functional connectivity.
- A combination of low-dose medetomidine and isoflurane is proposed as an optimal anesthesia regimen, preserving cortical and subcortical correlations without medetomidine's seizure risk.
