Medical/biological study (experimental study)

Radial arm maze performance of rats following repeated low level microwave radiation exposure med./bio.

By: Cobb BL, Jauchem JR, Adair ER

Published in: Bioelectromagnetics 2004; 25 (1): 49-57

Aim of study (acc. to author)

To examine possible changes in working memory of rats following whole body exposure to microwave irradiation.

Background/further details

Rats received a preexposure injection of one of three psychoactive compounds (physostigmine, naltrexone hydrochloride, naloxone methiodide) or saline, to determine whether a compound would interact with microwave irradiation to affect performance in the maze. The study was conducted as an attempt to confirm the results of a previous study (publication id 109).

Endpoint

cognitive/behavioral endpoints: working memory

Exposure

- low level microwaves
- PW pulsed wave

Exposure	Parameters
Exposure 1: 2.45 GHz Modulation type: pulsed Exposure duration: 45 min each on 10 testing days	SAR: 600 µW/g mean (whole body) (Dewar flask calorimetry and differential power method.)

Exposure 1

Main characteristics

Frequency	2.45 GHz
Exposure duration	45 min each on 10 testing days

Modulation

Modulation type	pulsed
Pulse width	2 µs
Packets per second	500

Exposure setup

Exposure source	waveguide
Chamber	Plexiglass chamber
Setup	waveguide constructed of galvanized wire screen in which a circularly polarized TE11 mode field configuration was realized
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	600 µW/g	mean	measured	whole body	Dewar flask calorimetry and differential power method.

Reference articles

Frei MR et al. (1998): Chronic exposure of cancer-prone mice to low-level 2450 MHz radiofrequency radiation
Lai H et al. (1994): Microwave irradiation affects radial-arm maze performance in the rat
Guy AW et al. (1979): Circularly polarized 2450 MHz waveguide system for chronic exposure of small animals to microwaves

Exposed system:

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: working memory, spatial memory task (radial arm maze; error rate (reentry into arms already visited); time taken by each rat to enter all of the 12 baited arms for 10 consecutive days of testing)

Investigated system:

investigation on living organism

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Analyzes of error rates revealed no significant irradiation effect, no significant drug effect and no significant interaction between the two factors. There was a significant difference in test days with repeated test-trial days, which indicates that learning was accomplished. There was no significant interaction of test day and the other two main factors. The results of the analyzes of time it took each rat to enter all of the 12 baited arms included no significant exposure effect, a significant drug effect, a significant test day effect, and a significant interaction between drug and test day factors.
The authors concluded that there is no evidence from the current study that exposure to microwave irradiation under these parameters caused decrements in the ability of rats to learn the spatial memory task. These findings and those of other studies of possible working memory changes show differing results.

Study character:

medical/biological study
experimental study
full/main study
replication/reproduction study

Study funded by

not stated/no funding

Replicated studies

Lai H et al. (1994): Microwave irradiation affects radial-arm maze performance in the rat

Comments on this article

Lai H (2005): Comment on "Radial arm maze performance of rats following repeated low level microwave radiation exposure"
Lai H (2005): Responses to Jauchem and Cassel

Maaroufi K et al. (2014): Spatial learning, monoamines and oxidative stress in rats exposed to 900 MHz electromagnetic field in combination with iron overload
Sinha RK (2008): Chronic non-thermal exposure of modulated 2450 MHz microwave radiation alters thyroid hormones and behavior of male rats
Ammari M et al. (2008): Effect of head-only sub-chronic and chronic exposure to 900-MHz GSM electromagnetic fields on spatial memory in rats
Cassel JC et al. (2004): Whole-body exposure to 2.45 GHz electromagnetic fields does not alter radial-maze performance in rats
Lai H et al. (1994): Microwave irradiation affects radial-arm maze performance in the rat