Taga Gentaro, Homae Fumitaka, Watanabe Hama
Graduate School of Education, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Neuroimage. 2007 Nov 15;38(3):452-60. doi: 10.1016/j.neuroimage.2007.07.050. Epub 2007 Aug 15.
One of the practical problems in neuroimaging using near infrared spectroscopy (NIRS) is to choose an appropriate source-detector distance to maximize the sensitivity to cerebral blood oxygenation and to improve the spatial resolution for mapping cortical activation. While NIRS has attracted increasing attention in neuroimaging in infants, there has been no report of comparative data regarding source-detector distance for the infant brain. In the present study, 9 quietly sleeping 3-month-old infants were exposed to 3-s speech sounds, and hemodynamic responses over the bilateral temporal cortices were assessed by using multiple pairs of source and detector of NIR light with varying distances (1, 2, 3 and 4 cm) and varying intensities (0.6 and 1.2 mW). The statistical analyses of the group-averaged hemodynamic responses and the frequency analyses of the signal-to-noise ratios revealed that a 2-cm source-detector distance with 0.6-mW NIR light provided the highest sensitivity to cortical responses. This indicates that NIRS can be used to detect the activation of the cortical regions, in the infant brain, by using the source-detector distance scaled to the smaller head size of infants and a relatively low intensity of NIR light compared to the ones that have been routinely used in adult studies.
使用近红外光谱技术（NIRS）进行神经成像时的一个实际问题是选择合适的源-探测器距离，以最大化对脑血氧合的敏感度，并提高映射皮层激活的空间分辨率。虽然NIRS在婴儿神经成像中越来越受到关注，但尚无关于婴儿脑源-探测器距离的比较数据报告。在本研究中，9名安静睡眠的3个月大婴儿暴露于3秒的语音中，通过使用多对不同距离（1、2、3和4厘米）和不同强度（0.6和1.2毫瓦）的近红外光源和探测器，评估双侧颞叶皮质的血流动力学反应。对组平均血流动力学反应的统计分析和信噪比的频率分析表明，使用0.6毫瓦近红外光、源-探测器距离为2厘米时，对皮层反应的敏感度最高。这表明，与成人研究中常规使用的相比，通过使用根据婴儿较小头围缩放的源-探测器距离和相对较低强度的近红外光，NIRS可用于检测婴儿脑皮层区域的激活。
