Medical/biological study (experimental study)

Single, brief exposure to a 50 Hz magnetic field does not affect the performance of an object recognition task in adult mice med./bio.

By: Sienkiewicz ZJ, Bartram R, Haylock RG, Saunders RD

Published in: Bioelectromagnetics 2001; 22 (1): 19-26

Aim of study (acc. to author)

To investigate the effects magnetic fields have on non-spatial working memory in mice.

Background/further details

In an object recognition task mice were first allowed to explore a stimulus object. Then mice were removed from the arena, exposed to a magnetic field and replaced in the test arena, which contained a novel object in addition to the original familiar object. The role (familiar vs. novel) and position of the two objects was counterbalanced and randomly assigned.Three different exposure groups (each n=17) and one sham exposure group (n=17) were studied.

Endpoint

cognitive/behavioral endpoints: non-spatial working memory

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 45 min	magnetic flux density: 750 µT maximum (7.5 µT, 75 µT, 750 µT)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 45 min

Exposure setup

Exposure source	coil(s)
Setup	electromagnet consisting of two sets of aluminum coils, 25 cm apart; animals in 33 cm x 15 cm x 13 cm polycarbonate cages in the bore of the magnet
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	750 µT	maximum	measured	-	7.5 µT, 75 µT, 750 µT

Reference articles

Kowalczuk CI et al. (1994): Effects of prenatal exposure to 50 Hz magnetic fields on development in mice: I. Implantation rate and fetal development

Exposed system:

animal
mouse/C57BL/6J
whole body

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: non-spatial working memory: spontaneous exploratory activity (object recognition task: mean exploration time of the familiar object and the novel object and mean total exploration time)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

During the first test phase, all groups showed similar levels of spontaneous exploratory activity.
During the second test phase, all groups showed comparable exploratory behavior: The familiar object was explored less than the novel object in all groups. No significant field-dependent effects on the performance of the task were observed at any magnetic flux density compared to sham exposed animals.
The results provide no evidence that non-spatial working memory was affected by acute exposure to a 50 Hz magnetic field in mice.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

not stated/no funding

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Sun H et al. (2010): Effects of prenatal exposure to a 50-Hz magnetic field on one-trial passive avoidance learning in 1-day-old chicks
Liu T et al. (2008): Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory
Delhez M et al. (2004): No influence of 20 and 400 µT, 50 Hz magnetic field exposure on cognitive function in humans