361 - EEG Hyperscanning to Investigate Maternal-Newborn Neural Activation in Response to Skin-to-Skin Affectionate Touch in the First Days After Birth

Poster Number: 361
Publication Number: 361.2904

Background: Affectionate touch is a fundamental aspect of the human experience, beginning at the start of life. The sensory pathway for affectionate touch is anatomically segregated, primarily transmitted by unmyelinated, slow-conducting C-tactile (CT) afferents optimally activated by gentle stroking at 1-10 cm/s. In the neonatal period, skin-to-skin and stroking touch tune long-term somatosensory development, autonomic reactivity, social cognition, and bonding; however, neonatal neural processing of affectionate touch is not well understood.

Objective: We aimed to examine neonatal brain responses to social/nonsocial and CT-targeted/non-CT-targeted touch stimuli and to interrogate the neural underpinnings of touch-mediated mother-infant interaction by recording simultaneous or “hyperscanning” maternal-newborn electroencephalography (EEG) at the neonatal cotside.

Design/Methods: Before recruitment, we incorporated the perspectives of 14 mother-newborn dyads to develop a participant-driven paradigm, which compares neural dynamics across touch context and mechanism in a 2x3 factorial design (Fig. 1). For touch context, mothers and infants are skin-to-skin (“social”) or separate (“nonsocial”). For touch mechanism, the infant receives still touch (“static”), slow stroking (~1-10 cm/s, “CT-optimal”), or fast stroking (~20 cm/s, “non-CT-optimal”) across the back with pre/post baselines. Simultaneous maternal-newborn EEG is recorded and synchronised with video to track stroking speed.

Results: We applied EEG hyperscanning to study 43 mother-newborn dyads. Clean data from at least one touch condition was present in 30 healthy term-born newborns (11 female; mean 3409 grams, 39+4 weeks gestation, 1.7 days old) with their mothers (mean 32.0 years old). We calculated neonatal broadband EEG power (μV²/Hz) across 1-10 Hz in frontal, central, and parietal regions, subtracting baseline, and found significant differences between social and nonsocial contexts for static and CT-optimal, but not non-CT-optimal, touch (n = 30) (Fig. 2).

Conclusion(s): We established and refined an EEG hyperscanning paradigm at the neonatal cotside across types of affectionate touch. Preliminary results indicate that static and CT-targeted touch stimuli elicit different neural responses in the newborn depending on the social context of the touch. Additional recruitment and analyses of maternal-newborn neural synchronicity are currently underway. We hope our results will help elucidate the roles of social touch stimuli and the CT afferent pathway in early brain development as well as help characterise the beginnings of the mother-child inter-brain network.