Tam Nicoladie, Pollonini Luca, Zouridakis George
Annu Int Conf IEEE Eng Med Biol Soc. 2016 Aug;2016:1580-1583. doi: 10.1109/EMBC.2016.7591014.
In this study we applied phase-space analysis on the hemodynamic signals recorded from the motor cortex of human subjects using functional near infrared spectroscopy (fNIRS) to decode the direction of intentional hand movements. Our goal is to develop a brain-computer-interface (BCI) based on optical imaging that can control a wheelchair. To establish the relationship between the hemodynamic response and movement direction, participants were asked to perform repetitive arm movements in two orthogonal directions (right-left and front-back) on a horizontal plane, while the time course of the oxy-hemoglobin (oxy-Hb) and deoxy-hemoglobin (deoxy-Hb) responses were recorded. We applied phase-space analysis on oxy-Hb and deoxy-Hb signals to characterize movement direction. Our results show that movement directions taken pairwise (left vs. right, and forward vs. backward) are mapped onto different quadrants in the oxy-Hb vs. deoxy-Hb phase plane. These findings demonstrate that phase-space analysis can be used to decode the movement direction in a BCI controlling a wheelchair. In conclusion, phase-space analysis can be used to differentiate intentional movement direction without correlating the temporal movement kinematics with the hemodynamic response.
在本研究中，我们对使用功能性近红外光谱（fNIRS）从人类受试者运动皮层记录的血流动力学信号进行相空间分析，以解码有意手部运动的方向。我们的目标是开发一种基于光学成像的脑机接口（BCI），用于控制轮椅。为了建立血流动力学反应与运动方向之间的关系，参与者被要求在水平面上沿两个正交方向（左右和前后）进行重复性手臂运动，同时记录氧合血红蛋白（oxy-Hb）和脱氧血红蛋白（deoxy-Hb）反应的时间进程。我们对oxy-Hb和deoxy-Hb信号进行相空间分析，以表征运动方向。我们的结果表明，两两组合的运动方向（左对右，前对后）映射到oxy-Hb与deoxy-Hb相平面的不同象限。这些发现表明，相空间分析可用于在控制轮椅的脑机接口中解码运动方向。总之，相空间分析可用于区分有意运动方向，而无需将时间运动运动学与血流动力学反应相关联。
