Developmental differences in visual evoked potential responses to high-frequency sensory tetanisation across adolescence and early adulthood

Adolescence is characterised by ongoing maturation of cortical circuits, yet little is known about how cortical responsiveness to repeated sensory stimulation changes across this developmental period. To address this question, we examined visual cortical responses to high-frequency sensory stimulation (HFS) in early adolescence, late adolescence, and adulthood using a sensory visual tetanisation paradigm. Visual evoked potentials (VEPs) were recorded from occipital and parieto-occipital regions during low-frequency visual stimulation (0.83 Hz) at baseline and 2, 4, and 20 min following HFS (8.87 Hz, 2 min). Post-HFS changes in the N1b and P2a VEP components, indexing early and later stages of visual processing, respectively, were used to quantify changes in cortical responsiveness. Across all age groups, N1b amplitudes showed sustained increases in both occipital and parieto-occipital regions following HFS, with no significant effects of age. In contrast, P2a amplitudes demonstrated age- and region-specific modulation. At occipital sites, all groups exhibited a comparable transient attenuation of P2a following HFS that returned to baseline levels. However, in parieto-occipital regions, P2a attenuation persisted across all post-HFS assessments in early adolescents, whereas in late adolescents and adults it recovered to baseline by 20 min post-HFS. These findings reveal a developmental dissociation between early and later stages of visual processing, with younger adolescents showing more sustained modulation of later neural responses. Together, the results suggest continued maturation of the mechanisms regulating cortical responsiveness to sensory stimulation across adolescence.