Medical/biological study (experimental study)

Chronic exposure to low-intensity magnetic field improves acquisition and maintenance of memory med./bio.

By: Liu T, Wang S, He L, Ye K

Published in: NeuroReport 2008; 19 (5): 549-552

Aim of study (acc. to author)

This study was performed to examine the effects of extremely low frequency magnetic field on spatial learning and memory in rats.

Background/further details

Adult, male rats weighing 160 to 180 g passed five training sessions (one session consisted of four trials) in which they learned to locate a submerged platform in a circular water maze. Probe trials were assessed every 1.5 hours and 24 hours after the last training trial during which the platform was removed to examine the retrieval of short-term and long-term spatial memory.

Endpoint

cognitive/behavioral endpoints: spatial learning and memory

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 1 h/day or 4 h/day for 4 weeks	magnetic flux density: 2 mT peak value

General information

rats were assigned to one of the three groups: 1) sham-exposure 2) daily exposure for 1 h 3) daily exposure for 4 h

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	1 h/day or 4 h/day for 4 weeks

Exposure setup

Exposure source	Helmholtz coils
Setup	pair of Helmholtz coils with a diameter of 80 cm and a coil separation of 40 cm; rats placed in the center of the coils
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2 mT	peak value	measured	-	-

Exposed system:

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: spatial learning and memory (Morris water maze test)

Main outcome of study (acc. to author)

The chronic exposure to extremely low frequency magnetic field reduced the latency to find the hidden platform. Concerning retrieval of spatial learning an improved long-term memory without affecting the short-term memory was observed.
These results indicate that chronic exposure to extremely low frequency magnetic field exerts a positive effect on the acquisition and maintenance of spatial memory in rats.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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