Medical/biological study (experimental study)

Magnetosensory function in rats: localization using positron emission tomography med./bio.

By: Frilot 2nd C, Carrubba S, Marino AA

Published in: Synapse 2009; 63 (5): 421-428

Aim of study (acc. to author)

To show that electromagnetic fields produce magnetosensory evoked potentials in rats and to localize the activated region in the brain.

Background/further details

The authors wanted to extend results from previous studies on magnetosensory evoked potentials in humans (publication 15027) and rabbits (publication 9242).
In the first experiment, 10 female rats were exposed to a magnetic field. In a second experiment, the effect of the magnetic field on the regional rate of glucose uptake was analyzed in another group of 10 rats using PET. Each rat was scanned twice: after field exposure and after sham exposure.

Endpoint

effects on the neurological system: magnetosensory evoked potentials; neuroanatomical localization

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Modulation type: pulsed Exposure duration: 45 min	magnetic flux density: 0.25 mT

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	45 min

Modulation

Modulation type	pulsed
Pulse width	2 s
Additional info	interstimulus period = 5 s

Exposure setup

Exposure source	coil(s)
Setup	rats placed in 28 cm x 18 cm x 13 cm non-metallic cages inside the coil
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.25 mT	-	-	-	-

Exposed system:

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: onset- and offset- magnetosensory evoked potentials (EEG); neuroanatomical localization (fluorodeoxyglucose uptake: PET)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

during exposure

Main outcome of study (acc. to author)

Onset magnetosensory evoked potentials were detected in all 10 rats, and offset magnetosensory evoked potentials were detected in 7 of the 10 rats.The magnetosensory evoked potentials were similar in magnitude, latency and dynamical origin to those exhibited by rabbits (see publication 9242) and humans (see publication 15027). Exposure to the magnetic field stimulated cerebellar uptake of fluorodeoxyglucose compared to the sham exposure in the same animals. The activated region was located in the posterior central cerebellum.
The results indicated that magnetosensory evoked potentials in rats were associated with increased glucose utilization in the cerebellum, thereby supporting earlier evidence that electromagnetic field transduction occurred in the brain.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Volkow ND et al. (2011): Effects of cell phone radiofrequency signal exposure on brain glucose metabolism
Frilot 2nd C et al. (2011): Transient and steady-state magnetic fields induce increased fluorodeoxyglucose uptake in the rat hindbrain
Carrubba S et al. (2009): The electric field is a sufficient physical determinant of the human magnetic sense
Carrubba S et al. (2008): Magnetosensory evoked potentials: consistent nonlinear phenomena
Carrubba S et al. (2008): The effects of low-frequency environmental-strength electromagnetic fields on brain electrical activity: a critical review of the literature
Carrubba S et al. (2007): Evidence of a nonlinear human magnetic sense
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Carrubba S et al. (2006): Detection of nonlinear event-related potentials
Marino AA et al. (2003): Consistent magnetic-field induced dynamical changes in rabbit brain activity detected by recurrence quantification analysis
Marino AA et al. (2003): Localization of electroreceptive function in rabbits
Marino AA et al. (2002): Consistent magnetic-field induced dynamical changes in rabbit brain activity detected by recurrence quantification analysis (Corrected and republished in Brain Res. 2003 Feb 28;964(2):317-26)
Sonnier H et al. (2001): Sensory transduction as a proposed model for biological detection of electromagnetic fields
Bell GB et al. (1992): Alterations in brain electrical activity caused by magnetic fields: detecting the detection process