Medical/biological Study (experimental study)

A magnetic field effect on learning in male golden hamsters. med./biol.

PubMed Entry

Journal web site

Aim of study (according to author)
To investigate the influence of repeated exposure to 10, 20, 30 or 40 Hz magnetic fields on the learning behavior of hamsters in a skinner box.
Background/further details:
Male hamsters were assigned randomly to an exposure group (n=12) or sham exposure group (n=12).
The behavioural tests in the skinner box were performed on the following day after the last exposure. In the Skinner box the animals learned to press a lever to receive a food reward (unconditioned stimulus), which was associated with the sound of pressing the lever (conditioned stimulus). As a result a conditioned response was created (index of learning).

Endpoint

• cognitive/behavioral endpoints: learning: conditioned response

Exposure
General category: magnetic field, low frequency field, signals/pulses

Field characteristics	Parameters
10 - 40 Hz pulsed (PW) exposure duration: 30 min/day on 8 consecutive days	magnetic flux density: 100 mT

Exposed system:
animal (species/strain): golden hamster (Mesocricetus auratus)
whole body exposure

Methods
Endpoint/Measurement parameters/Methodology

• cognitive/behavioral endpoints: conditioned response: number of presses of the lever, associated with eating the food tablet; latency of the first response

Main outcome of study (according to author)
The latency of the first response was not affected by exposure to the magnetic fields.
No significant effects on the performance of the task were observed in animals exposed to 10 and 20 Hz magnetic fields.
Exposure significantly improved the learning of the task in animals exposed to 30 and 40 Hz magnetic fields: The exposed animals needed fewer lever pressings to create the conditioned response and learned the task more quickly than sham-exposed animals.
The results indicate that the effects of magnetic fields on the process of learning in animals are dependent on the applied frequencies.

(Study character: medical/biological study, experimental study, full/main study, blind study)

Study funded by

• not stated/none

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• Lai H (1996): Spatial learning deficit in the rat after exposure to a 60 Hz magnetic field.
• Stern S et al. (1996): Exposure to combined static and 60 Hz magnetic fields: failure to replicate a...
• Sienkiewicz ZJ et al. (1996): Prenatal exposure to a 50 Hz magnetic field has no effect on spatial learning...
• Kavaliers M et al. (1996): Spatial learning in deer mice: sex differences and the effects of endogenous...
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• Trzeciak HI et al. (1993): Behavioral effects of long-term exposure to magnetic fields in rats.
• Rudolph K et al. (1985): Weak 50-Hz electromagnetic fields activate rat open field behavior.
• Davis HP et al. (1984): Behavioral studies with mice exposed to DC and 60-Hz magnetic fields.