Department of Research, Development, and Education, Sint Maartenskliniek Nijmegen, PO Box 9011, 6500 GM Nijmegen, The Netherlands.
J Neural Eng. 2012 Aug;9(4):046010. doi: 10.1088/1741-2560/9/4/046010. Epub 2012 Jul 4.
The poor spatial resolution of near-infrared spectroscopy (NIRS) makes it difficult to distinguish two closely located cortical areas from each other. Here, a combination of multi-channel NIRS and a centre of gravity (CoG) approach (widely accepted in the field of transcranial magnetic stimulation; TMS) was used to discriminate between closely located cortical areas activated during hand and foot movements. Similarly, the possibility of separating the more anteriorly represented discrete movements from rhythmic movements was studied. Thirteen healthy right-handed subjects performed rhythmic or discrete ('task') hand or foot ('extremity') tapping. Hemodynamic responses were measured using an 8-channel NIRS setup. For oxyhemoglobin (OHb) and deoxyhemoglobin (HHb), a CoG was determined for each condition using the mean hemodynamic responses and the coordinates of the channels. Significant hemodynamic responses were found for hand and foot movements. Based on the HHb responses, the NIRS-CoG of hand movements was located 0.6 cm more laterally compared to the NIRS-CoG of foot movements. For OHb responses no difference in NIRS-CoG was found for 'extremity' nor for 'task'. This is the first NIRS study showing hemodynamic responses for isolated foot movements. Furthermore, HHb responses have the potential to be used in multi-channel NIRS experiments requiring differential activation of motor cortex areas linked to either hand or foot movements.
近红外光谱（NIRS）的空间分辨率较差，难以区分彼此相邻的两个皮质区域。在这里，我们结合使用多通道 NIRS 和重心（CoG）方法（该方法在经颅磁刺激领域被广泛接受；TMS），以区分在手部和脚部运动过程中激活的彼此相邻的皮质区域。同样，我们还研究了分离更靠前的离散运动和节律运动的可能性。13 名健康的右利手受试者进行节律性或离散性（“任务”）手部或脚部（“肢体”）敲击。使用 8 通道 NIRS 设备测量血液动力学反应。对于氧合血红蛋白（OHb）和脱氧血红蛋白（HHb），使用平均血液动力学反应和通道坐标为每个条件确定 CoG。在手部和脚部运动中发现了明显的血液动力学反应。基于 HHb 反应，手部运动的 NIRS-CoG 比脚部运动的 NIRS-CoG 更偏向外侧 0.6 厘米。对于 OHb 反应，在“肢体”和“任务”方面，NIRS-CoG 没有差异。这是第一项显示孤立脚部运动血液动力学反应的 NIRS 研究。此外，HHb 反应有可能用于需要区分与手部或脚部运动相关的运动皮质区域的差异激活的多通道 NIRS 实验。
