Study type: Medical/biological study (experimental study)

Geophysical variables and behavior: XCIX. Reductions in numbers of neurons within the parasolitary nucleus in rats exposed perinatally to a magnetic pattern designed to imitate geomagnetic continuous pulsations: implications for sudden infant death med./bio.

By: Dupont MJ, McKay BE, Parker G, Persinger MA
Published in: Percept Mot Skills 2004; 98 (3): 958-966
Download citation in RIS format

Aim of study (acc. to author)

To investigate the effects of magnetic field exposure on neuron development in rat brain.

Background/further details

Rats were continously exposed to pulsed magnetic fields from two days before birth to one week after birth. At three weeks of age tissue slices of a special part of the brain (the parasolitary nucleus) were investigated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 500 mHz
Modulation type: pulsed
Exposure duration: continuous for 9 days ( 2 days befor and 7 days after birth)

Exposure 1

Main characteristics
Frequency 500 mHz
Type
Waveform
Exposure duration continuous for 9 days ( 2 days befor and 7 days after birth)
Modulation
Modulation type pulsed
Pulse width 600 ms
Pulse type rectangular
Additional info

wave onset (transient spike) with a rise time between 1.5 and 3.5 µs and offset (similar spike) with opposite polarity
Exposure setup
Exposure source
Setup two aluminum racks seperated by 2 m and arranged in either east-west or north-south direction, wrapped with 72 turns of 30-gauge copper wire Rats were exposed in plastic cages where the magnetic field was perpendicular to the horizontal plane.
Additional info The amplitude of the magnetic fields changed every 30 min and were applied in the following order: 870 nT, 1.04 µT, 1.3 µT, 1.77 µT, 1.33 µT, 1.04 µT and 8 nT. This order was called one cycle and each day such six cycles were applied.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 870 nT unspecified measured - -
magnetic flux density 1.04 µT unspecified measured - -
magnetic flux density 1.3 µT unspecified measured - -
magnetic flux density 1.77 µT unspecified measured - -
magnetic flux density 1.33 µT unspecified measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The parasolitary nucleus was found to be significantly smaller, and the number of neurones were significantly reduced in exposed rats. The results of this study suggest that magnetic fields, when applied in a nano-Tesla range and in a specific direction, might interact with the local geomagnetic field to affect cell structures in the rat brain.

Study character:

Study funded by