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Importance of alignment between local DC magnetic field and an oscillating magnetic field in responses of brain tissue in vitro and in vivo
Author(s) -
Blackman C. F.,
Benane S. G.,
House D. E.,
Elliott D. J.
Publication year - 1990
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/bem.2250110207
Subject(s) - magnetic field , nuclear magnetic resonance , in vivo , magnetostatics , calcium , biophysics , perpendicular , ion , field (mathematics) , bioelectromagnetics , in vitro , materials science , condensed matter physics , physics , chemistry , biology , biochemistry , mathematics , microbiology and biotechnology , geometry , quantum mechanics , pure mathematics , metallurgy
The frequency dependence of the electric and magnetic (EM)‐field‐induced release of calcium ions from an in vitro brain tissue preparation has been shown to be a function of the density of the local DC magnetic field (B dC ). In this study, we demonstrate that the relative orientation of the B dc and the magnetic component (B ac ) of a 315‐Hz EM signal (15 V rms /m and 61 nT rms ) are crucial for the induced release to be observed. The induced release occurs only when the B dc and the B ac are perpendicular, and not when they are parallel. This finding is consistent with a magnetic resonance‐like transduction mechanism for the conversion of EM energy into a physicochemical change, and contrasts with the requirement for parallel B dc and B ac components in the diatom‐mobility experiments of Smith et al. A review of the exposure conditions in the rat behavioral experiments conducted by Thomas et al. identifies unhydrated calcium and zinc ions as alternatives to lithium ions as candidates for interaction under parallel magnetic‐field orientations but fails to reject perpendicular orientations as an alternative basis for the phenomenon. Investigators that attempt to confirm the rat behavioral experiments should be aware of the conflicting exposure conditions that can be assumed to be operative, and they should design their experiments to test all conditions accordingly.