Repeated head-exposures to a 5G-3.5 GHz signal do not alter behavior but modify intracerebral gene expression in adult male mice.

The 5th generation (5G) of mobile communications promotes human exposures to electromagnetic fields exploiting the 3.5 GHz frequency band. We have analyzed behaviors, cognitive functions and gene expression in mice submitted to asymmetrical head-exposures to a 5G-modulated 3.5 GHz signal. The exposures were applied 1h daily, 5 days per week over a six-week period, at a specific absorption rate (SAR) averaging 0.19 W/kg over the brain. Locomotor activity in an open-field, object-place and object recognition memories were assessed repeatedly after four weeks of exposure and did not reveal any significant effect on the locomotion/exploration, anxiety level or memory processes. mRNA profiling was performed at the end of the exposure period in two symmetrical areas of the right and left cerebral cortex in which the SAR values were 0.43 and 0.14 W/kg, respectively. We found significant changes in the expression of less than 1% of the expressed genes with over-representations of genes related to glutamatergic synapses. The right cortical area differed from the left one by an over-representation of responsive genes encoded by the mitochondrial genome. Our data show that repeated head-exposures to a 5G-3.5 GHz signal can trigger mild transcriptome alterations without change in memory capacities or emotional state.