Neural Tissues Filter Electromagnetic Fields: Investigating Regional Processing of Induced Current in Ex vivo Brain Specimens

摘要

As has been demonstrated experimentally, the living brain responds to pulsatile electromagnetic fields. Our aimwas to investigate the capacities of ex vivo neural tissue to process and filter induced current generated by naturallyoccurring and laboratory-controlled electromagnetic fields. Microvolt potentials within the chemically fixed postmortembrains were collected throughout the field exposures. During strong geomagnetic storms there was asignificant increase in power spectra within the 7.5 Hz to 14 Hz range within the right but not the leftparahippocampal gyrus compared to days with relatively quiet geomagnetic activity. This finding indicated thatambient electromagnetic fluctuations from natural sources were processed differentially as a function of subsectionsof the postmortem tissue. Exposing a whole, fixed human brain to two physiologically patterned magnetic fields thathave been associated with powerful subjective experiences reported by hundreds of human volunteers in thelaboratory setting elicited increased power within the 7.5 Hz to 20 Hz range. The effects required 10 to 20 s toemerge and were primarily represented within tissue subsections of the right amygdala and orbitofrontal gyri. Otherfields such as simple sine-wave (20 Hz) patterns of comparable intensity (2 to 10 μT) did not elicit the sameconfiguration of changes. The results indicate that neural tissues filter electromagnetic fields non-randomly.