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Effect of radio-frequency electromagnetic fields on nervous tissue

Effect of radio-frequency electromagnetic fields on nervous tissue
Effect of radio-frequency electromagnetic fields on nervous tissue

Current safety guidelines are based on well-established thermal effects of radiofrequency radiation (RF).  The presence of non-thermal biological effects could undermine the basis of these standards, particularly for pulses with high peak fields but low average power.

This work has confirmed previous observations that exposure to low intensity RF fields can affect simple evoked responses in brain tissue slices in vitro.  The effects were seen at specific absorption rates (SAR) up to 4.4mW.kg-1 and were therefore not associate with heating.

Direct dosimetric measurement of the SAR within a brain tissue slice was not quantifiable by micro-thermocouple probe, due to perturbation of the E-field by the metal thermocouple.  Non-perturbing temperature probe and thermal imaging camera measurements could not discern any measurable temperature rise during RF exposure due to inadequate resolution.

Studies of physiological mechanisms suggested that RF exposure reduced the effectiveness of inhibitory mechanisms in the brain tissue, whilst having little effect on the excitability of nerve cells.  The reduction in inhibition showed no signs of recovery up to 15 minutes after the end of the exposure period.

Pharmacological experiments indicated that NMDA receptors and gap junctions may be involved in the RF-induced effects; suggestions are made for further experiments to help resolve this issue.

RF exposure potentiated the expression of stress-induced heat shock proteins at 41°C in organotypic hippocampal slice cultures.  This effect was similar to that previously reported in nematode worms and indicates that similar effects can occur in mammalian brain tissue.

University of Southampton
Deans, Jacqueline Kim
Deans, Jacqueline Kim

Deans, Jacqueline Kim (2003) Effect of radio-frequency electromagnetic fields on nervous tissue. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Current safety guidelines are based on well-established thermal effects of radiofrequency radiation (RF).  The presence of non-thermal biological effects could undermine the basis of these standards, particularly for pulses with high peak fields but low average power.

This work has confirmed previous observations that exposure to low intensity RF fields can affect simple evoked responses in brain tissue slices in vitro.  The effects were seen at specific absorption rates (SAR) up to 4.4mW.kg-1 and were therefore not associate with heating.

Direct dosimetric measurement of the SAR within a brain tissue slice was not quantifiable by micro-thermocouple probe, due to perturbation of the E-field by the metal thermocouple.  Non-perturbing temperature probe and thermal imaging camera measurements could not discern any measurable temperature rise during RF exposure due to inadequate resolution.

Studies of physiological mechanisms suggested that RF exposure reduced the effectiveness of inhibitory mechanisms in the brain tissue, whilst having little effect on the excitability of nerve cells.  The reduction in inhibition showed no signs of recovery up to 15 minutes after the end of the exposure period.

Pharmacological experiments indicated that NMDA receptors and gap junctions may be involved in the RF-induced effects; suggestions are made for further experiments to help resolve this issue.

RF exposure potentiated the expression of stress-induced heat shock proteins at 41°C in organotypic hippocampal slice cultures.  This effect was similar to that previously reported in nematode worms and indicates that similar effects can occur in mammalian brain tissue.

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Published date: 2003

Identifiers

Local EPrints ID: 465218
URI: http://eprints.soton.ac.uk/id/eprint/465218
PURE UUID: b6cd7fe7-8ec4-43ca-ad9f-10c12255e2ab

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Date deposited: 05 Jul 2022 00:29
Last modified: 05 Jul 2022 04:33

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Contributors

Author: Jacqueline Kim Deans

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