Long-term behavioral effects observed in mice chronically exposed to static ultra-high magnetic fields

Ivan Tkáč, Michael A. Benneyworth, Tessa Nichols-Meade, Elizabeth L. Steuer, Sarah N. Larson, Gregory J. Metzger, Kâmil Uğurbil

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: The primary goal of this study was to investigate whether chronic exposures to ultra-high B0 fields can induce long-term cognitive, behavioral, or biological changes in C57BL/6 mice. Methods: C57BL/6 mice were chronically exposed to 10.5-T or 16.4-T magnetic fields (3-h exposures, two exposure sessions per week, 4 or 8 weeks of exposure). In vivo single-voxel 1H magnetic resonance spectroscopy was used to investigate possible neurochemical changes in the hippocampus. In addition, a battery of behavioral tests, including the Morris water-maze, balance-beam, rotarod, and fear-conditioning tests, were used to examine long-term changes induced by B0 exposures. Results: Hippocampal neurochemical profile, cognitive, and basic motor functions were not impaired by chronic magnetic field exposures. However, the balance-beam–walking test and the Morris water-maze testing revealed B0-induced changes in motor coordination and balance. The tight-circling locomotor behavior during Morris water-maze tests was found as the most sensitive factor indexing B0-induced changes. Long-term behavioral changes were observed days or even weeks subsequent to the last B0 exposure at 16.4 T but not at 10.5 T. Fast motion of mice in and out of the 16.4-T magnet was not sufficient to induce such changes. Conclusion: Observed results suggest that the chronic exposure to a magnetic field as high as 16.4 T may result in long-term impairment of the vestibular system in mice. Although observation of mice may not directly translate to humans, nevertheless, they indicate that studies focused on human safety at very high magnetic fields are necessary.

Original languageEnglish (US)
Pages (from-to)1544-1559
Number of pages16
JournalMagnetic resonance in medicine
Volume86
Issue number3
DOIs
StateAccepted/In press - 2021

Bibliographical note

Funding Information:
The preparation of this manuscript was supported by NIH grants P41‐EB015894, P41‐EB027061 and P30‐NS076408

Publisher Copyright:
© 2021 International Society for Magnetic Resonance in Medicine

Keywords

  • battery of behavioral tests
  • chronic exposure
  • neurochemical profiling
  • tight circling
  • ultra-high magnetic fields
  • vestibular system

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