Medical/biological study (experimental study)

Effects of exposure to 50 Hz magnetic field of 1mT on the performance of detour learning task by chicks med./bio.

By: Che Y, Sun H, Cui Y, Zhou D, Ma Y

Published in: Brain Res Bull 2007; 74 (1-3): 178-182

Aim of study (acc. to author)

To study the effects of exposure to an extremely low frequency magnetic field on learning and memory in chicks.

Background/further details

Detour behaviour is the ability of an animal to reach a stimulus (goal) when there is an obstacle between the subject and the stimulus. Detour learning in chicks has been used as a functional test for the development of nervous system.
Since the sensitive phase for spatial memory development is around post hatch day 11, 32 chicks were exposed to 50 Hz magnetic fields before and after day 11 (for about 7 days, from day 9 until day 14 post hatch) and the detour learning task was performed (daily). 32 chicks were divided into 4 groups: 1) exposure group (20 h/day); 2) sham exposure; 3) exposure group (50 min/day); 4) sham exposure.

Endpoint

cognitive/behavioral endpoints: learning and memory

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 20 h/day or 50 min/day for 6 days	magnetic flux density: 1 mT

General information

chickens were treated in four groups: 1) EMF exposure for 20 h/day 2) sham exposure for 20 h/day 3) EMF exposure for 50 min/day 4) sham exposure for 50 min/day

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	20 h/day or 50 min/day for 6 days

Exposure setup

Exposure source	coil(s)
Setup	coil consisting of a 70 cm x 40 cm x 43 cm plastic frame and 4 layers of 250 turns each; 60 cm x 30 cm x 43 cm exposure area inside the coil; chickens placed in a 50 cm x 25 cm x 25 cm wooden box in the exposure area
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1 mT	-	-	-	-

Reference articles

Lei Y et al. (2005): Effects of extremely low-frequency electromagnetic fields on morphine-induced conditioned place preferences in rats

Exposed system:

animal
chicken/Lohmann brown
whole body

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: learning and memory (detour learning task)
body weight

Investigated system:

investigation on living organism

Time of investigation:

during exposure

Main outcome of study (acc. to author)

The data showed that 20 h/day exposure to a low frequency magnetic field induced a significant impairment in detour learning (the chicks needed more time to learn the task than the controls) but 50 min/day exposure had no effect.
The data provide the evidence of possible cognitive and biological effects of exposure to extremely low frequency magnetic fields.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Chinese Academy of Sciences
Chinese National Science Foundation
National Basic Research Program (Program 973), China

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