Maria Ambika, Hirvi Pauliina, Kotilahti Kalle, Heiskala Juha, Tuulari Jetro J, Karlsson Linnea, Karlsson Hasse, Nissilä Ilkka
University of Turku, Department of Clinical Medicine, Turku Brain and Mind Center, FinnBrain Birth Cohort Study, Finland; University of Turku and Turku University Hospital, Department of Psychiatry, Finland.
Aalto University, Department of Neuroscience and Biomedical Engineering, P.O. Box 12200, AALTO FI-00076, Finland; Aalto University, Department of Mathematics and Systems Analysis, Finland.
Neuroimage. 2022 May 1;251:118983. doi: 10.1016/j.neuroimage.2022.118983. Epub 2022 Feb 9.
Touch is an important component of early parent-child interaction and plays a critical role in the socio-emotional development of children. However, there are limited studies on touch processing amongst children in the age range from one to three years. The present study used frequency-domain diffuse optical tomography (DOT) to investigate the processing of affective and non-affective touch over left frontotemporal brain areas contralateral to the stimulated forearm in two-year-old children. Affective touch was administered by a single stroke with a soft brush over the child's right dorsal forearm at 3 cm/s, while non-affective touch was provided by multiple brush strokes at 30 cm/s. We found that in the insula, the total haemoglobin (HbT) response to slow brushing was significantly greater than the response to fast brushing (slow > fast). Additionally, a region in the postcentral gyrus, Rolandic operculum and superior temporal gyrus exhibited greater response to fast brushing than slow brushing (fast > slow). These findings confirm that an adult-like pattern of haemodynamic responses to affective and non-affective touch can be recorded in two-year-old subjects using DOT. To improve the accuracy of modelling light transport in the two-year-old subjects, we used a published age-appropriate atlas and deformed it to match the exterior shape of each subject's head. We estimated the combined scalp and skull, and grey matter (GM) optical properties by fitting simulated data to calibrated and coupling error corrected phase and amplitude measurements. By utilizing a two-compartment cerebrospinal fluid (CSF) model, the accuracy of estimation of GM optical properties and the localization of activation in the insula was improved. The techniques presented in this paper can be used to study neural development of children at different ages and illustrate that the technology is well-tolerated by most two-year-old children and not excessively sensitive to subject movement. The study points the way towards exciting possibilities in functional imaging of deeper functional areas near sulci in small children.
触摸是早期亲子互动的重要组成部分，对儿童的社会情感发展起着关键作用。然而，关于1至3岁儿童触摸处理的研究有限。本研究使用频域扩散光学断层扫描（DOT）来研究两岁儿童对刺激前臂对侧的左额颞脑区的情感和非情感触摸的处理。情感触摸通过用软刷以3厘米/秒的速度单次刷过儿童右背侧前臂来施加，而非情感触摸则通过以30厘米/秒的速度多次刷动来提供。我们发现，在脑岛中，对缓慢刷动的总血红蛋白（HbT）反应明显大于对快速刷动的反应（慢>快）。此外，中央后回、罗兰多岛盖和颞上回的一个区域对快速刷动的反应比对缓慢刷动的反应更大（快>慢）。这些发现证实，使用DOT可以在两岁受试者中记录到与成人相似的对情感和非情感触摸的血流动力学反应模式。为了提高对两岁受试者光传输建模的准确性，我们使用了已发表的适合年龄的图谱并对其进行变形以匹配每个受试者头部的外部形状。我们通过将模拟数据拟合到校准和耦合误差校正后的相位和幅度测量值来估计头皮和颅骨以及灰质（GM）的光学特性。通过使用双室脑脊液（CSF）模型，提高了GM光学特性估计的准确性以及脑岛中激活的定位。本文介绍的技术可用于研究不同年龄儿童的神经发育，并表明该技术在大多数两岁儿童中耐受性良好，对受试者运动不太敏感。该研究为幼儿脑沟附近更深功能区域的功能成像带来了令人兴奋的可能性。
