Altered theta-band sensory gating in individuals with high sensory processing sensitivity (SPS).

Sensory processing sensitivity (SPS) is a personality trait characterized by heightened responsiveness to environmental stimuli, yet its neurophysiological mechanisms remain unclear. Sensory gating (SG), an inhibitory process that suppresses redundant or irrelevant sensory inputs, is often assessed through event-related potentials (ERPs) but may also rely on non-phase-locked oscillatory activity. The present study examined SG in individuals with high versus low SPS using both time-domain and time-frequency electrophysiological measures while strictly controlling for serotonin transporter polymorphism (5-HTTLPR). From an initial cohort of 518 adults, participants in the top and bottom 10 % of Highly Sensitive Person (HSP) Scale scores who were homozygous for the S allele (SS genotype) completed a paired-stimulus auditory SG paradigm (26 high SPS; 25 low SPS). Time-domain analyses showed no group differences in SG ratios or SG differences of the N100 component. In contrast, time-frequency analyses revealed that individuals with high SPS exhibited significantly stronger gating in theta oscillations compared to low-SPS individuals (false discovery rate corrected p < 0.05). These findings suggest that SPS is not characterized by uniformly weaker sensory inhibition, but rather by altered oscillatory sensory-gating dynamics during repetitive sensory processing. In conclusion, theta-band SG may represent a candidate electrophysiological correlate of SPS and highlights the potential value of oscillatory measures for understanding individual differences in sensory responsiveness.