Srinivasan Sruthi, Acharya Deepshikha, Butters Emilia, Collins-Jones Liam, Mancini Flavia, Bale Gemma
Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
Front Neuroergon. 2024 Feb 19;5:1283290. doi: 10.3389/fnrgo.2024.1283290. eCollection 2024.
Functional near-infrared spectroscopy (fNIRS) is a widely used imaging method for mapping brain activation based on cerebral hemodynamics. The accurate quantification of cortical activation using fNIRS data is highly dependent on the ability to correctly localize the positions of light sources and photodetectors on the scalp surface. Variations in head size and shape across participants greatly impact the precise locations of these optodes and consequently, the regions of the cortical surface being reached. Such variations can therefore influence the conclusions drawn in NIRS studies that attempt to explore specific cortical regions. In order to preserve the spatial identity of each NIRS channel, subject-specific differences in NIRS array registration must be considered. Using high-density diffuse optical tomography (HD-DOT), we have demonstrated the inter-subject variability of the same HD-DOT array applied to ten participants recorded in the resting state. We have also compared three-dimensional image reconstruction results obtained using subject-specific positioning information to those obtained using generic optode locations. To mitigate the error introduced by using generic information for all participants, photogrammetry was used to identify specific optode locations per-participant. The present work demonstrates the large variation between subjects in terms of which cortical parcels are sampled by equivalent channels in the HD-DOT array. In particular, motor cortex recordings suffered from the largest optode localization errors, with a median localization error of 27.4 mm between generic and subject-specific optodes, leading to large differences in parcel sensitivity. These results illustrate the importance of collecting subject-specific optode locations for all wearable NIRS experiments, in order to perform accurate group-level analysis using cortical parcellation.
功能近红外光谱技术（fNIRS）是一种广泛应用的成像方法，用于基于脑血流动力学绘制大脑激活图。使用fNIRS数据对皮质激活进行准确量化高度依赖于在头皮表面正确定位光源和光探测器位置的能力。不同参与者的头部大小和形状变化会极大地影响这些光极的精确位置，进而影响所到达的皮质表面区域。因此，这种变化可能会影响在试图探索特定皮质区域的近红外光谱研究中得出的结论。为了保持每个近红外光谱通道的空间一致性，必须考虑近红外光谱阵列配准中个体之间的差异。我们使用高密度漫射光学断层扫描（HD-DOT），展示了将相同的HD-DOT阵列应用于10名处于静息状态的参与者时个体之间的变异性。我们还比较了使用个体特定定位信息获得的三维图像重建结果与使用通用光极位置获得的结果。为了减轻对所有参与者使用通用信息所引入的误差，采用摄影测量法来确定每个参与者的特定光极位置。目前的工作表明，在HD-DOT阵列中，等效通道对哪些皮质区域进行采样方面，个体之间存在很大差异。特别是，运动皮层记录受光极定位误差的影响最大，通用光极和个体特定光极之间的定位误差中位数为27.4毫米，导致区域敏感性存在很大差异。这些结果说明了为所有可穿戴近红外光谱实验收集个体特定光极位置的重要性，以便使用皮质分区进行准确的组水平分析。
