Characterization of cortical activation patterns during movement of the upper extremity in healthy adults is helpful in understanding recovery mechanisms following neurological disorders. This study explores cortical activation patterns associated with movements of the shoulder and fingers in healthy adults using functional near-infrared spectroscopy (fNIRS). Twelve healthy right-handed participants were recruited. Two motor tasks (shoulder abduction and finger extension) with two different trial lengths (10 s and 20 s) were performed in a sitting position at a rate of 0.5 Hz. The hemodynamic response, as indicated by oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR), over both hemispheres was acquired using a 54-channel fNIRS system. We found a generalized bilateral cortical activation during both motor tasks with greater activation in the contralateral compared to the ipsilateral primary motor cortex. Particularly in the more medial part of the contralateral hemisphere, significant higher activation was found during the shoulder compared to finger movements. Furthermore, cortical activation patterns are affected not only by motor tasks but also by trial lengths. HbO is more sensitive to detect cortical activation during finger movements in longer trials, while HbR is a better surrogate to capture active areas during shoulder movement in shorter trials. Based on these findings, reporting both HbO and HbR is strongly recommended for future fNIRS studies, and trial lengths should be taken into account when designing experiments and explaining results. Our findings demonstrating distinct cortical activation patterns associated with shoulder and finger movements in healthy adults provide a foundation for future research to study recovery mechanisms following neurological disorders.

中文翻译：

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健康成人肩部和手指运动期间的皮质激活：一项功能性近红外光谱 (fNIRS) 研究

健康成人上肢运动过程中皮质激活模式的特征有助于理解神经系统疾病后的恢复机制。本研究使用功能性近红外光谱 (fNIRS) 探索与健康成人肩部和手指运动相关的皮质激活模式。招募了 12 名健康的右手参与者。在坐姿下以 0.5 Hz 的频率执行具有两种不同试验长度（10 秒和 20 秒）的两项运动任务（肩外展和手指伸展）。使用 54 通道 fNIRS 系统获取两个半球的血流动力学响应，如氧合血红蛋白 (HbO) 和脱氧血红蛋白 (HbR) 所示。与同侧初级运动皮层相比，我们发现在两种运动任务中都有广泛的双侧皮层激活，对侧的激活更大。特别是在对侧半球的更内侧部分，与手指运动相比，肩部的活动显着更高。此外，皮质激活模式不仅受运动任务的影响，还受试验长度的影响。在较长时间的试验中，HbO 对检测手指运动过程中的皮层激活更敏感，而 HbR 是在较短试验中检测肩部运动过程中活动区域的更好替代物。基于这些发现，强烈建议在未来的 fNIRS 研究中报告 HbO 和 HbR，并且在设计实验和解释结果时应考虑试验长度。