Repeated Head Exposures to a 5G-3.5 GHz Signal Do Not Alter Behavior but Modify Intracortical Gene Expression in Adult Male Mice

Abstract

Category: Neuroscience Tags: 5G, electromagnetic fields, gene expression, behavioral neuroscience, specific absorption rate, glutamatergic synapses, mitochondrial genome DOI: 10.3390/ijms26062459 URL: mdpi.com Overview The fifth generation (5G) of mobile communications introduces new frequencies, such as the 3.5 GHz band, increasing human and animal exposure to electromagnetic fields (EMF). This study analyzed the effects of asymmetrical head exposure to a 5G-modulated 3.5 GHz signal on adult male mice over a six-week period. - Exposures were 1 hour daily, 5 days a week, at a specific absorption rate (SAR) averaging 0.19 W/kg over the brain. - Behavioral assessments included locomotor activity, anxiety, object location, and object recognition memory tests after four weeks of exposure. - Gene expression (mRNA profiling) was analyzed post-exposure in two regions of the cerebral cortex. Findings - No significant effects on locomotion, anxiety, or memory were found. - Significant but limited gene expression changes occurred—affecting less than 1% of expressed genes, with over-representation related to glutamatergic synapses. - Differences emerged between right and left cortical regions, especially in genes encoded by the mitochondrial genome. - SAR values in the cortex were 0.43 W/kg (right) and 0.14 W/kg (left). Conclusion Key Takeaways: - Repeated head exposures to 5G-3.5 GHz signals do not appear to affect memory capacities or emotional state in adult male mice under tested conditions. - The exposures did trigger detectable transcriptomic alterations, particularly in genes related to synaptic function and mitochondrial activity. - Potential health risks from intracortical gene expression modifications should not be downplayed, especially as long-term or subtle effects may manifest with different exposure durations or in more sensitive populations. Limitations The authors caution that effects beyond six weeks, in female mice, or assessed with additional behavioral tests, remain unknown. The reversibility and real-world relevance of these gene expression changes require further investigation, especially given differences between experimental and environmental SAR levels.

AI evidence extraction

Main findings

Repeated asymmetrical head exposure to a 5G-modulated 3.5 GHz signal (average brain SAR 0.19 W/kg) produced no significant effects on locomotion/exploration, anxiety level, or object location/recognition memory. mRNA profiling at the end of exposure found significant expression changes in less than 1% of expressed genes, with over-representation of glutamatergic synapse-related genes and, in the higher-SAR right cortical area, an over-representation of responsive genes encoded by the mitochondrial genome.

Outcomes measured

• Locomotor activity (open field)
• Exploration/anxiety level (open field)
• Object location memory
• Object recognition memory
• Intracortical gene expression (mRNA profiling; transcriptome changes)
• Glutamatergic synapse-related gene expression
• Mitochondrial genome-encoded responsive genes (hemispheric differences)

Limitations

• Sample size not reported in the provided abstract/metadata
• Animal study (adult male mice); generalizability to humans not established in the provided abstract
• Exposure was asymmetrical head exposure; cortical areas had different SARs (0.43 vs 0.14 W/kg), complicating interpretation
• Behavioral outcomes assessed after four weeks; gene expression assessed only at end of six-week exposure

Suggested hubs

• 5g-policy (0.55)
  Study explicitly examines a 5G-modulated 3.5 GHz signal exposure.

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    "exposure": {
        "band": "RF",
        "source": "5G-modulated signal (head exposure)",
        "frequency_mhz": 3500,
        "sar_wkg": 0.190000000000000002220446049250313080847263336181640625,
        "duration": "1 h daily, 5 days/week for 6 weeks"
    },
    "population": "Adult male mice",
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    "outcomes": [
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        "Exploration/anxiety level (open field)",
        "Object location memory",
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        "Intracortical gene expression (mRNA profiling; transcriptome changes)",
        "Glutamatergic synapse-related gene expression",
        "Mitochondrial genome-encoded responsive genes (hemispheric differences)"
    ],
    "main_findings": "Repeated asymmetrical head exposure to a 5G-modulated 3.5 GHz signal (average brain SAR 0.19 W/kg) produced no significant effects on locomotion/exploration, anxiety level, or object location/recognition memory. mRNA profiling at the end of exposure found significant expression changes in less than 1% of expressed genes, with over-representation of glutamatergic synapse-related genes and, in the higher-SAR right cortical area, an over-representation of responsive genes encoded by the mitochondrial genome.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in the provided abstract/metadata",
        "Animal study (adult male mice); generalizability to humans not established in the provided abstract",
        "Exposure was asymmetrical head exposure; cortical areas had different SARs (0.43 vs 0.14 W/kg), complicating interpretation",
        "Behavioral outcomes assessed after four weeks; gene expression assessed only at end of six-week exposure"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
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        "3.5 GHz",
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        "head exposure",
        "specific absorption rate",
        "SAR",
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        "behavior",
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        "open field",
        "object recognition",
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