Functional magnetic resonance imaging can be used to explore tactile and nociceptive processing in the infant brain.

Gemma Williams,Irene Tracey,Judith Meek,Rebeccah Slater,Nicola Robertson,Lorenzo Fabrizi,Deborah Jackson,Maria Fitzgerald

doi:10.1111/apa.12848

Abstract

AimDespite the importance of neonatal skin stimulation, little is known about activation of the newborn human infant brain by sensory stimulation of the skin. We carried out functional magnetic resonance imaging (fMRI) to assess the feasibility of measuring brain activation to a range of mechanical stimuli applied to the skin of neonatal infants.MethodsWe studied 19 term infants with a mean age of 13 days. Brain activation was measured in response to brushing, von Frey hair (vFh) punctate stimulation and, in one case, nontissue damaging pinprick stimulation of the plantar surface of the foot. Initial whole brain analysis was followed by region of interest analysis of specific brain areas.ResultsDistinct patterns of functional brain activation were evoked by brush and vFh punctate stimulation, which were reduced, but still present, under chloral hydrate sedation. Brain activation increased with increasing stimulus intensity. The feasibility of using pinprick stimulation in fMRI studies was established in one unsedated healthy full-term infant.ConclusionDistinct brain activity patterns can be measured in response to different modalities and intensities of skin sensory stimulation in term infants. This indicates the potential for fMRI studies in exploring tactile and nociceptive processing in the infant brain.

Highlights

The newborn human infant is almost continuously exposed to mechanical skin stimulation, whether it is through maternal contact, wrapping or spontaneous twitching and there is increasing evidence that this tactile input plays an important role in the growth and development of the brain [1,2]
Key notes This study used functional magnetic resonance imaging to assess the feasibility of measuring brain activation to a range of mechanical stimuli applied to the skin of neonatal infants
Our findings demonstrate the feasibility of using functional magnetic resonance imaging (fMRI) to explore tactile and nociceptive processing in the infant brain

Summary

Introduction

The newborn human infant is almost continuously exposed to mechanical skin stimulation, whether it is through maternal contact, wrapping or spontaneous twitching and there is increasing evidence that this tactile input plays an important role in the growth and development of the brain [1,2]. Little is currently known about somatosensory processing in the human infant brain or the pattern of activation in cortical and subcortical regions evoked by tactile and noxious stimulation of the newborn body surface. To cutaneous stimulation and display prolonged noxious evoked responses which gradually decrease with gestational age [4] This reflex activity, along with observed behaviours such as facial expressions and crying, and physiological responses, such as increased heart rate variability [5] confirm functional links between the somatosensory system and the motor and autonomic nervous system in even the most premature infants, but shed little light on how this information is processed at higher subcortical and cortical levels. Key notes This study used functional magnetic resonance imaging (fMRI) to assess the feasibility of measuring brain activation to a range of mechanical stimuli applied to the skin of neonatal infants

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