title: Mapping Cortical Responses to Somatosensory Stimuli in Human Infants with Simultaneous Near-Infrared Spectroscopy and Event-Related Potential Recording.
abstract: Near-infrared spectroscopy (NIRS) and electroencephalography (EEG) have recently provided fundamental new information about how the newborn brain processes innocuous and noxious somatosensory information. However, results derived independently from these two techniques are not entirely consistent, raising questions about the relationship between hemodynamic and electrophysiological responses in the study of touch and pain processing in the newborn. To address this, we have recorded NIRS and EEG responses simultaneously for the first time in the human infant following noxious (time-locked clinically required heel lances) and innocuous tactile cutaneous stimulation in 30 newborn infants. The results show that both techniques can be used to record quantifiable and distinct innocuous and noxious evoked activity at a group level in the newborn cortex. Noxious stimulation elicits a peak hemodynamic response that is 10-fold larger than that elicited by an innocuous stimulus (HbO2: 2.0 vs 0.3 µM) and a distinct nociceptive-specific N3P3 waveform in electrophysiological recordings. However, a novel single-trial analysis revealed that hemodynamic and electrophysiological responses do not always co-occur at an individual level, although when they do (64% of noxious test occasions), they are significantly correlated in magnitude. These data show that, while hemodynamic and electrophysiological touch and pain brain activity in newborn infants are comparable in group analyses, important individual differences remain. These data indicate that integrated and multimodal brain monitoring is required to understand central touch and pain processing in the newborn.
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Madeleine
authors.identifier: 0000-0003-3019-0370
authors.initials: M
authors.lastname: Verriotis
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Fabrizi
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Amy
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Cooper
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, University College London , London WC1E 6BT, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Fitzgerald
authors.affiliation: Elizabeth Garrett Anderson Obstetric Wing, University College Hospital, University College London Hospitals , London, WC1E 6DB, United Kingdom.
authors.forename: Judith
authors.initials: J
authors.lastname: Meek
mesh_terms: D001931:Brain Mapping; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007223:Infant; D008297:Male; D000069336:Neurovascular Coupling / Q000502:physiology*; D010108:Oxyhemoglobins / Q000378:metabolism; D010146:Pain / Q000503:physiopathology; D010812:Physical Stimulation; D025341:Principal Component Analysis; D012867:Skin / Q000294:innervation; D013003:Somatosensory Cortex / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared; D014110:Touch / Q000502:physiology
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin
keywords: EEG; hemodynamic; multimodal; neurovascular coupling; noxious; pain