Affective and non-affective touch evoke differential brain responses in 2-month-old infants

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Emma H. Jönsson
  • Kalle Kotilahti

  • Juha Heiskala
  • Helena Backlund Wasling
  • Håkan Olausson
  • Ilona Croy
  • Hanna Mustaniemi
  • Petri Hiltunen
  • Jetro J. Tuulari
  • Noora M. Scheinin
  • Linnea Karlsson
  • Hasse Karlsson
  • Ilkka Nissilä

Research units

  • University of Gothenburg
  • University of Helsinki
  • Linköping University
  • Technische Universität Dresden
  • University of Turku
  • Aalto University

Abstract

Caressing touch is an effective way to communicate emotions and to create social bonds. It is also one of the key mediators of early parental bonding. The caresses are generally thought to represent a social form of touching and indeed, slow, gentle brushing is encoded in specialized peripheral nerve fibers, the C-tactile (CT) afferents. In adults, areas such as the posterior insula and superior temporal sulcus are activated by affective, slow stroking touch but not by fast stroking stimulation. However, whether these areas are activated in infants, after social tactile stimulation, is unknown. In this study, we compared the total hemoglobin responses measured with diffuse optical tomography (DOT) in the left hemisphere following slow and fast stroking touch stimulation in 16 2-month-old infants. We compared slow stroking (optimal CT afferent stimulation) to fast stroking (non-optimal CT stimulation). Activated regions were delineated using two methods: one based on contrast between the two conditions, and the other based on voxel-based statistical significance of the difference between the two conditions. The first method showed a single activation cluster in the temporal cortex with center of gravity in the middle temporal gyrus where the total hemoglobin increased after the slow stroking relative to the fast stroking (p = 0.04 uncorrected). The second method revealed a cluster in the insula with an increase in total hemoglobin in the insular cortex in response to slow stroking relative to fast stroking (p = 0.0005 uncorrected; p = 0.04 corrected for multiple comparisons). These activation clusters encompass areas that are involved in processing of affective, slow stroking touch in the adult brain. We conclude that the infant brain shows a pronounced and adult-like response to slow stroking touch compared to fast stroking touch in the insular cortex but the expected response in the primary somatosensory cortex was not found at this age. The results imply that emotionally valent touch is encoded in the brain in adult-like manner already soon after birth and this suggests a potential for involvement of touch in bonding with the caretaker.

Details

Original languageEnglish
Pages (from-to)162-171
Number of pages10
JournalNeuroImage
Volume169
Publication statusPublished - 1 Apr 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • Affective touch, Diffuse optical tomography (DOT), Functional near infrared spectroscopy, Infant

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