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Authors & Affiliations
Camila Fragoso Ribeiro, Isabella Germinhasi Francischelli, Lívia Branco Campos, Lilia Sofia Ferreira de Sousa Cardoso, Borja Blanco, Sarah Lloyd-Fox, Rogério de Oliveira, Sergio Luiz Novi Junior, Rickson Coelho Mesquita, Ana Alexandra Caldas Osório
Abstract
Social touch is crucial for optimal human development, given its contributions to emotional and behavioral regulation. Research has identified a set of tactile afferents – C-Tactile (CT) fibers – that fire specifically in response to receiving gentle touch on the skin. These fibers have been shown to project not only to somatosensory areas of the brain but also to social regions. There is also evidence that the processing of social touch is highly influenced by contextual factors, such as the identity of the person delivering the touch. This study aimed to compare the neural activation patterns of 10-month-old infants in response to perceived touch from their mothers versus touch from an unfamiliar woman. Using fNIRS (functional near-infrared spectroscopy), 14 infants were assessed while sitting in a chair and watching a non-social video. They were softly stroked (3 cm/s) in a 4 cm2 area of the left shoulder blade by a trained researcher hidden behind a curtain. In 8 trials, the mother sat next to the child, while in the remaining 8 trials, the unfamiliar female sat beside the infant. When infants believed they were being touched by their mothers (versus an unfamiliar female), we found a greater activation on the channels over the following brain regions: Primary Somatosensory Cortex (right side and left) and Secondary Somatosensory Cortex (right side) and Temporoparietal Junction (right side). These preliminary results show important differences in social touch processing modulated by partner identity in young infants.