This pilot animal study exposed mature male Wistar rats to 4.9 GHz electromagnetic fields described as 5G-standard, for 15 days (2 hours/day) in a semi-anechoic shielded chamber. Open-field testing found no clear behavioral differences between unmodulated and modulated exposures. Statistically significant behavioral changes occurred in both exposed and control animals, which the authors attribute to changes in the environmental electromagnetic background, making causal interpretation uncertain.