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Effects of Head-Only Exposure to 900 MHz GSM Electromagnetic Fields in Rats: Changes in Neuronal Activity as Revealed by c-Fos Imaging without Concomitant Cognitive Impairments.

Biomedicines · 2024 · Mixed · Low evidence

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MixedLow evidencePaper 5825

In an acute 2 h head-only exposure study (brain average SAR 0.5–6 W/kg), neuronal activation changes were dose-dependent, with significant increases in c-Fos expression at 1 W/kg in prelimbic, infralimbic, frontal, and cingulate cortices. In a second study wi…

Study snapshot

PublicationBiomedicines · 2024
Study typeanimal
Reported directionMixed
Evidence ratingLow

Abstract

Over the last two decades, animal models have been used to evaluate the physiological and cognitive effects of mobile phone exposure. Here, we used a head-only exposure system in rats to determine whether exposure to 900 MHz GSM electromagnetic fields (EMFs) induces regional changes in neuronal activation as revealed by c-Fos imaging. In a first study, rats were exposed for 2 h to brain average specific absorption rates (BASARs) ranging from 0.5 to 6 W/kg. Changes in neuronal activation were found to be dose-dependent, with significant increases in c-Fos expression occurring at BASAR of 1 W/kg in prelimbic, infralimbic, frontal, and cingulate cortices. In a second study, rats were submitted to either a spatial working memory (WM) task in a radial maze or a spatial reference memory (RM) task in an open field arena. Exposures (45 min) were conducted before each daily training session (BASARs of 1 and 3.5 W/kg). Control groups included sham-exposed and control cage animals. In both tasks, behavioral performance evolved similarly in the four groups over testing days. However, c-Fos staining was significantly reduced in cortical areas (prelimbic, infralimbic, frontal, cingulate, and visual cortices) and in the hippocampus of animals engaged in the WM task (BASARs of 1 and 3.5 W/kg). In the RM task, EMF exposure-induced decreases were limited to temporal and visual cortices (BASAR of 1 W/kg). These results demonstrate that both acute and subchronic exposures to 900 MHz EMFs can produce region-specific changes in brain activity patterns, which are, however, insufficient to induce detectable cognitive deficits in the behavioral paradigms used here.

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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 directionmixed
PopulationRats
Sample sizeNot supplied
ExposureRF · 900 MHz · 6 W/kg · Study 1: 2 h acute exposure; Study 2: 45 min exposures before each daily training session (subchronic; number of days not stated)
Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

In an acute 2 h head-only exposure study (brain average SAR 0.5–6 W/kg), neuronal activation changes were dose-dependent, with significant increases in c-Fos expression at 1 W/kg in prelimbic, infralimbic, frontal, and cingulate cortices. In a second study with 45 min exposures before daily training (BASAR 1 and 3.5 W/kg), behavioral performance in working and reference memory tasks was similar across exposed, sham, and cage control groups, while c-Fos staining was significantly reduced in multiple cortical areas and hippocampus during the working memory task and reduced in temporal/visual cortices in the reference memory task (at 1 W/kg).

Outcomes measured

  • Neuronal activation (c-Fos expression/imaging)
  • Spatial working memory task performance (radial maze)
  • Spatial reference memory task performance (open field arena)

Limitations

  • Sample size not reported in provided abstract/metadata
  • Number of training/exposure days in the subchronic protocol not stated
  • Outcomes limited to c-Fos staining and performance in the specific behavioral paradigms used
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "RF",
    "source": "mobile phone (GSM)",
    "frequency_mhz": 900,
    "sar_wkg": 6,
    "duration": "Study 1: 2 h acute exposure; Study 2: 45 min exposures before each daily training session (subchronic; number of days not stated)"
  },
  "population": "Rats",
  "sample_size": null,
  "outcomes": [
    "Neuronal activation (c-Fos expression/imaging)",
    "Spatial working memory task performance (radial maze)",
    "Spatial reference memory task performance (open field arena)"
  ],
  "main_findings": "In an acute 2 h head-only exposure study (brain average SAR 0.5–6 W/kg), neuronal activation changes were dose-dependent, with significant increases in c-Fos expression at 1 W/kg in prelimbic, infralimbic, frontal, and cingulate cortices. In a second study with 45 min exposures before daily training (BASAR 1 and 3.5 W/kg), behavioral performance in working and reference memory tasks was similar across exposed, sham, and cage control groups, while c-Fos staining was significantly reduced in multiple cortical areas and hippocampus during the working memory task and reduced in temporal/visual cortices in the reference memory task (at 1 W/kg).",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size not reported in provided abstract/metadata",
    "Number of training/exposure days in the subchronic protocol not stated",
    "Outcomes limited to c-Fos staining and performance in the specific behavioral paradigms used"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "rat",
    "head-only exposure",
    "GSM",
    "900 MHz",
    "RF-EMF",
    "brain average SAR (BASAR)",
    "c-Fos",
    "neuronal activation",
    "prelimbic cortex",
    "infralimbic cortex",
    "cingulate cortex",
    "hippocampus",
    "working memory",
    "reference memory"
  ],
  "suggested_hubs": [
    {
      "slug": "mobile-phones-rf",
      "weight": 0.9,
      "reason": "Head-only 900 MHz GSM exposure modelled as mobile phone RF-EMF."
    }
  ]
}
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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: 10.3390/biomedicines12091954
PubMed: 39335468

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