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

After 4 weeks of repeated asymmetrical head exposure to a 5G-modulated 3.5 GHz signal, no significant effects were observed on locomotion, anxiety, or object location/recognition memory. Post-exposure mRNA profiling in two cortical regions showed significant but limited transcriptomic changes (<1% of expressed genes), with over-representation related to glutamatergic synapses and right/left differences particularly involving mitochondrial genome-encoded genes. Reported cortical SAR values were 0.43 W/kg (right) and 0.14 W/kg (left), with an average brain SAR of 0.19 W/kg.

Outcomes measured

• Locomotor activity
• Anxiety-related behavior
• Object location memory
• Object recognition memory
• Intracortical gene expression (mRNA profiling) in two cerebral cortex regions
• Cortical SAR distribution (right vs left cortex)

Limitations

• Sample size not reported in provided abstract/metadata
• Behavioral testing was conducted after four weeks; longer-term behavioral outcomes beyond six weeks are not assessed
• Only adult male mice were studied; results may not generalize to females
• Only selected behavioral tests were used; other neurobehavioral endpoints were not assessed
• Reversibility and real-world relevance of observed gene expression changes are stated as requiring further investigation
• Experimental exposure/SAR conditions may differ from environmental exposures

Suggested hubs

• 5g-policy (0.62)
  Study explicitly examines a 5G-modulated 3.5 GHz exposure and reports biological/behavioral outcomes.

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    "exposure": {
        "band": "RF",
        "source": "5G mobile communications (3.5 GHz signal); asymmetrical head exposure",
        "frequency_mhz": 3500,
        "sar_wkg": 0.190000000000000002220446049250313080847263336181640625,
        "duration": "6 weeks; 1 hour/day, 5 days/week"
    },
    "population": "Adult male mice",
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    "outcomes": [
        "Locomotor activity",
        "Anxiety-related behavior",
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        "Object recognition memory",
        "Intracortical gene expression (mRNA profiling) in two cerebral cortex regions",
        "Cortical SAR distribution (right vs left cortex)"
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    "main_findings": "After 4 weeks of repeated asymmetrical head exposure to a 5G-modulated 3.5 GHz signal, no significant effects were observed on locomotion, anxiety, or object location/recognition memory. Post-exposure mRNA profiling in two cortical regions showed significant but limited transcriptomic changes (<1% of expressed genes), with over-representation related to glutamatergic synapses and right/left differences particularly involving mitochondrial genome-encoded genes. Reported cortical SAR values were 0.43 W/kg (right) and 0.14 W/kg (left), with an average brain SAR of 0.19 W/kg.",
    "effect_direction": "mixed",
    "limitations": [
        "Sample size not reported in provided abstract/metadata",
        "Behavioral testing was conducted after four weeks; longer-term behavioral outcomes beyond six weeks are not assessed",
        "Only adult male mice were studied; results may not generalize to females",
        "Only selected behavioral tests were used; other neurobehavioral endpoints were not assessed",
        "Reversibility and real-world relevance of observed gene expression changes are stated as requiring further investigation",
        "Experimental exposure/SAR conditions may differ from environmental exposures"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
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        "memory",
        "locomotion",
        "gene expression",
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