Touch Modulates Gamma-Band Network Dynamics in the Infant Brain

Touch is a foundational sensory modality in early development, playing a pivotal role in shaping social, emotional, and cognitive functions. This study focused on EEG data from 8-month-old infants to investigate the neural networks underlying the processing of naturalistic hand-to-hand touch-both felt and observed. Unlike prior research in which infants were presented with artificial stimuli, we employed ecologically valid, caregiver-like tactile interactions to better capture real-world dynamics. Our findings reveal that felt touch elicited widespread, highly coordinated gamma-band activity across sensory and higher-order cortical areas, supporting early integration of bodily experiences with attentional and perceptual systems. Observed touch, while activating a more localized somatosensory network, still demonstrated distinct gamma connectivity, consistent with early self-other differentiation. A control condition involving observed failed contact elicited increased frontal and temporal activity, possibly reflecting expectancy violation and heightened attentional demands. These results underscore the significance of touch in scaffolding early neural architecture, especially within sensorimotor and social-cognitive domains. Furthermore, our findings highlight the value of analyzing multiple frequency bands beyond traditional μ rhythm desynchronization to understand infant mirroring mechanisms. Importantly, this study advances our understanding of how early tactile experiences may shape the developing connectome, revealing gamma oscillations as a marker of sensorimotor processing and emerging intersubjective awareness.