Conspicuous histomorphological anomalies in the hippocampal formation of rats exposed prenatally to a complex sequenced magnetic field within the nanoTesla range.

Perceptual and motor skills · 2003 · Harm · Low evidence

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HarmLow evidencePaper 3707

Study snapshot

PublicationPerceptual and motor skills · 2003

Study typeanimal

Reported directionHarm

Evidence ratingLow

Abstract

The brains of adult rats, exposed prenatally to one of four intensities (between 10 nanoTesla and 1.2 microTesla) of either a frequency-modulated magnetic field or a complex sequenced field designed to affect brain development, were examined histologically. Although from each intensity some rats that had been exposed to the complex sequenced magnetic field showed minor anomalies, those exposed to intensities between 30 nT and 180 nT exhibited conspicuous anomalous organizations of cells within the hippocampal formation. In other studies, rats that had been exposed during their entire prenatal development to the complex sequenced field displayed significantly more activity in the open field and poorer spatial memory during maze learning. Photomicrographs are shown of one conspicuous morphological anomaly within the right hippocampus of an adult rat exposed prenatally to the complex sequenced magnetic field with intensities between .3 mG and .5 mG (30 nT to 50 nT). The results suggest that complex magnetic fields, whose temporal structures approach the time constants of normal biochemical processes, can permanently alter the development of the brain.

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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 (prenatal exposure; adult brains examined)

Sample sizeNot supplied

ExposureELF · entire prenatal development (prenatal exposure); assessed in adulthood

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Adult rats exposed prenatally to a complex sequenced magnetic field showed histological anomalies in the hippocampal formation, described as conspicuous at intensities between 30 nT and 180 nT. The abstract also notes that in other studies, rats exposed throughout prenatal development to the complex sequenced field showed significantly more open-field activity and poorer spatial memory during maze learning.

Outcomes measured

Histological anomalies in hippocampal formation
Open-field activity
Spatial memory during maze learning

Limitations

Sample size not reported in abstract
Exposure frequency characteristics not specified beyond being frequency-modulated/complex sequenced
Behavioral outcomes are referenced as occurring in 'other studies' without details in this abstract
No quantitative effect sizes or statistical details provided for histological findings

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "entire prenatal development (prenatal exposure); assessed in adulthood"
  },
  "population": "Rats (prenatal exposure; adult brains examined)",
  "sample_size": null,
  "outcomes": [
    "Histological anomalies in hippocampal formation",
    "Open-field activity",
    "Spatial memory during maze learning"
  ],
  "main_findings": "Adult rats exposed prenatally to a complex sequenced magnetic field showed histological anomalies in the hippocampal formation, described as conspicuous at intensities between 30 nT and 180 nT. The abstract also notes that in other studies, rats exposed throughout prenatal development to the complex sequenced field showed significantly more open-field activity and poorer spatial memory during maze learning.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not reported in abstract",
    "Exposure frequency characteristics not specified beyond being frequency-modulated/complex sequenced",
    "Behavioral outcomes are referenced as occurring in 'other studies' without details in this abstract",
    "No quantitative effect sizes or statistical details provided for histological findings"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "prenatal exposure",
    "magnetic field",
    "nanoTesla",
    "microTesla",
    "complex sequenced field",
    "frequency-modulated magnetic field",
    "hippocampus",
    "histology",
    "open field",
    "spatial memory",
    "maze learning"
  ],
  "suggested_hubs": [
    {
      "slug": "animal-studies",
      "weight": 0.9,
      "reason": "Prenatal magnetic-field exposure in rats with histological and behavioral outcomes."
    }
  ]
}

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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: 10.2466/pms.2003.97.3f.1307
PubMed: 15002875

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