Sex-dependent cortical responses to terpene-based olfactory stimulation revealed by EEG and sLORETA

Olfactory stimulation with volatile terpenes has been associated with modulation of human brain activity; however, sex-dependent neurophysiological responses to terpene-derived aromas remain unclear. This study investigated cortical responses to orange- and pine-derived terpene aromas using relative spectral power analysis of electroencephalography (EEG) rhythms and standardized low-resolution electromagnetic tomography (sLORETA). Volatile and odor-active compounds were characterized using an electronic nose (E-nose) and gas chromatography-mass spectrometry-olfactometry (GC-MS-O), indicating terpene-dominant profiles in both aroma samples. EEG recordings were obtained before, during, and after aroma inhalation. Significant sex-dependent differences in cortical responses were observed. In males, orange aroma induced significant increases in relative beta- and gamma-band power, particularly in the temporal and occipital regions. In females, pine aroma produced a significant increase in relative beta-band power, mainly in the frontal and occipital regions. sLORETA analysis further revealed distinct cortical activation patterns associated with aroma type and sex. These findings indicate that terpene-based olfactory stimulation differentially modulates cortical EEG responses in males and females, providing neurophysiological evidence for sex-dependent processing of olfactory stimuli.