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Rats avoid high magnetic fields: dependence on an intact vestibular system.
Thomas A Houpt1, Jennifer A Cassell, Christina Riccardi
1Department of Biological Science, Biomedical Research Facility 209 MC 4340, The Florida State University, Tallahassee, FL 32306, USA. houpt@neuro.fsu.edu
Physiology & Behavior
|June 26, 2007
Summary
Rats avoid high magnetic fields, detecting 2 T fields and avoiding entry into 14.1 T magnets. This avoidance relies on the inner ear, suggesting a novel sensory mechanism for magnetic field detection in mammals.
Area of Science:
- Neuroscience
- Sensory Biology
- Biophysics
Background:
- High-strength static magnetic fields from MRI machines are increasing.
- Potential aversive effects of these fields on mammals are not well understood.
- Mammals are generally thought to be insensitive to magnetic fields.
Purpose of the Study:
- To investigate the behavioral responses of mammals to high static magnetic fields.
- To determine the threshold at which magnetic fields become aversive to rats.
- To identify the sensory mechanisms involved in magnetic field detection.
Main Methods:
- Rats were trained to navigate through the bore of a 14.1 T superconducting magnet.
- Behavioral avoidance was assessed at different magnetic field strengths (1-14 T).
- The role of the vestibular apparatus was tested using labyrinthectomized rats.
Main Results:
- Rats found entry into a 14.1 T magnet aversive.
- Rats detected and avoided magnetic fields at or below 2 T.
- Labyrinthectomized rats did not avoid the magnetic fields, indicating vestibular involvement.
Conclusions:
- Mammals can detect and behaviorally respond to static magnetic fields.
- The vestibular system in the inner ear is crucial for magnetic field detection.
- This finding may explain human experiences of vertigo and nausea with high-field MRI.
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