Transient and steady-state magnetic fields induce increased fluorodeoxyglucose uptake in the rat hindbrain.

Synapse (New York, N.Y.) · 2011 · Harm · Low evidence

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HarmLow evidencePaper 3278

Rats exposed to a 2.5-G, 60-Hz magnetic field showed increased glucose utilization (FDG uptake) in hindbrain voxels when the field was applied orthogonally to the sagittal plane, but not when the field direction varied randomly. Distinct FDG activation effect…

Study snapshot

PublicationSynapse (New York, N.Y.) · 2011

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

We inquired into the biophysical basis of the ability of weak electromagnetic fields (EMFs) to trigger onset and offset evoked potentials, and to produce steady-state changes in the electroencephalogram (EEG). Rats were exposed to a 2.5-G, 60-Hz magnetic field and the neuroanatomical region of glucose activation associated with the effect of the field on the EEG was identified by positron emission tomography (PET) using fluorodeoxyglucose (FDG). Paired emission scans from the same animal with and without field treatment were differenced and averaged, and t values of the brain voxels computed using the pooled standard deviation were compared with a calculated critical t value to identify the field-activated voxels. Increased glucose utilization occurred in hindbrain voxels when the field was applied orthogonally to the sagittal plane, but not when the angle between the field and the sagittal plane varied randomly. Distinct FDG activation effects were observed in response to transient (both onset and offset) and steady-state magnetic stimuli. Observations of increased glucose utilization induced by magnetic stimuli and its dependence on the direction of the field suggested that signal transduction was mediated by a force detector and that the process and/or early post-transduction processing occurred in the hindbrain.

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionharm

PopulationRats

Sample sizeNot supplied

ExposureELF · 0.06 MHz

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Outcomes measured

FDG (fluorodeoxyglucose) uptake / glucose utilization in brain (PET)
EEG changes (context for identifying activation region)

Limitations

Sample size not reported in abstract
Exposure duration not reported in abstract
Outcome is metabolic activation (FDG uptake) rather than a clinical/behavioral endpoint
Details of randomization/blinding and statistical correction for multiple voxel comparisons not described in abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": 0.06,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Rats",
  "sample_size": null,
  "outcomes": [
    "FDG (fluorodeoxyglucose) uptake / glucose utilization in brain (PET)",
    "EEG changes (context for identifying activation region)"
  ],
  "main_findings": "Rats exposed to a 2.5-G, 60-Hz magnetic field showed increased glucose utilization (FDG uptake) in hindbrain voxels when the field was applied orthogonally to the sagittal plane, but not when the field direction varied randomly. Distinct FDG activation effects were reported for transient (onset/offset) versus steady-state magnetic stimuli.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in abstract",
    "Exposure duration not reported in abstract",
    "Outcome is metabolic activation (FDG uptake) rather than a clinical/behavioral endpoint",
    "Details of randomization/blinding and statistical correction for multiple voxel comparisons not described in abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "ELF magnetic field",
    "60 Hz",
    "2.5 G",
    "rat",
    "hindbrain",
    "FDG",
    "PET",
    "glucose utilization",
    "EEG",
    "transient onset/offset",
    "steady-state"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.25,
      "reason": "Study involves ELF (60 Hz) magnetic-field exposure, which is commonly relevant to occupational ELF contexts, though no workplace setting is specified."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1002/syn.20882
PubMed: 21484881

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