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

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.

What do we really know about newborn infant pain?

“…In a study of 19 term infants with a mean age of 13 days, distinct patterns of functional brain activation were evoked by brush and von Frey hair punctate stimulation, which were reduced, but still present, under chloral hydrate sedation. Brain activation increased with increasing von Frey hair stimulus intensity (Williams et al 2015), revealing the ability of the newborn brain to code stimulus intensity. A feasibility study in a single full-term infant (Williams et al 2015) laid the foundation for an fMRI study of 10 newborn infants, which identified the network of brain regions that are active following pinprick stimulation .…”

“…Brain activation increased with increasing von Frey hair stimulus intensity (Williams et al 2015), revealing the ability of the newborn brain to code stimulus intensity. A feasibility study in a single full-term infant (Williams et al 2015) laid the foundation for an fMRI study of 10 newborn infants, which identified the network of brain regions that are active following pinprick stimulation . The blood-oxygen-level-dependent (BOLD) response in newborn infants was compared with that observed after the same pinprick stimulation in adults, and significant infant brain activity was observed in 18 of the 20 active adult brain regions, including primary somatosensory cortices, anterior cingulate cortex, bilateral thalamus and all divisions of the insular cortices, but not in the infant amygdala or orbitofrontal cortex.…”

“…Clinically required, tissue-breaking stimuli are hard to adapt to magnetic imaging, so functional magnetic resonance imaging (fMRI) studies have relied on experimental brushing, von Frey hair punctate and pinprick stimulation of the skin (Williams et al 2015;Goksan et al 2015). In a study of 19 term infants with a mean age of 13 days, distinct patterns of functional brain activation were evoked by brush and von Frey hair punctate stimulation, which were reduced, but still present, under chloral hydrate sedation.…”

“…Recently, the field has turned to exciting new evidence of pain-induced activity in the brain of human infants, which offers real insight into how pain is processed at higher levels of the newborn CNS (Slater et al 2006(Slater et al , 2010cFabrizi et al 2011;Williams et al 2015;Goksan et al 2015). This has provided previously unknown information about how much noxious information reaches the newborn brain and has opened the door to new research into the functional development of early nociceptive circuits in the somatosensory cortex and other brain areas in man.…”

Beyond the N1: A review of late somatosensory evoked responses in human infants

“…MEG and functional magnetic resonance imaging (fMRI) studies with adults have identified an extended network of areas activated by somatosensory stimulation that includes the posterior parietal cortex and other areas (Bardouille & Ross, 2008; Porro et al, 2004). Although some work has attempted using fMRI to study tactile stimulation in infants (Archi et al, 2010; Williams et al, 2015), MEG and EEG are likely to remain the main techniques for examining somatosensory processing in infancy due the methodological challenges of fMRI research with this age group.…”