Mehta Jay P, Verber Matthew D, Wieser Jon A, Schmit Brian D, Schindler-Ivens Sheila M
Department of Physical Therapy, Marquette University, Milwaukee, WI 53201-1881, USA.
J Neurosci Methods. 2009 May 15;179(2):230-9. doi: 10.1016/j.jneumeth.2009.01.029. Epub 2009 Feb 7.
Advances in neural imaging technologies, such as functional magnetic resonance imaging (fMRI), have made it possible to obtain images of human brain activity during motor tasks. However, technical challenges have made it difficult to image the brain during multijoint lower limb movements like those involved in locomotion. We developed an MR compatible pedaling device and recorded human brain activity associated with rhythmic, alternating flexion and extension of the lower extremities. Ten volunteers pedaled at 30 RPM while recording fMRI signals in a GE 3T short bore MR scanner. We utilized a block design consisting of 3 runs of pedaling, each lasting 4 min. In a single run, subjects pedaled for 30 s and then rested for 30 s. This sequence was repeated 4 times. Conventional fMRI processing techniques, that correlate the entire BOLD signal with standard model, did not extract physiologically meaningful signal, likely due to magnetic field distortion caused by leg movement. Hence, we examined only the portion of the blood-oxygen-level dependent (BOLD) signal during movement-free periods. This technique takes advantage of the delayed nature of the BOLD signal and fits the falling portion of the signal after movement has stopped with a standard model. Using this approach, we observed physiologically plausible brain activity patterns associated with pedaling in the primary and secondary sensory and motor cortices and the cerebellum. To our knowledge, this is the first time that human brain activity associated with pedaling has been recorded with fMRI. This technique may be useful for advancing our understanding of supraspinal control of locomotor-like movements in health and disease.
神经成像技术的进步，如功能磁共振成像（fMRI），使得在运动任务期间获取人类大脑活动图像成为可能。然而，技术挑战使得在多关节下肢运动（如行走中涉及的运动）期间对大脑进行成像变得困难。我们开发了一种与磁共振兼容的踏板装置，并记录了与下肢有节奏的交替屈伸相关的人类大脑活动。十名志愿者以每分钟30转的速度踩踏板，同时在通用电气3T短孔径磁共振扫描仪中记录功能磁共振成像信号。我们采用了一种组块设计，包括3次踩踏板运行，每次持续4分钟。在一次运行中，受试者踩踏板30秒，然后休息30秒。这个序列重复4次。传统的功能磁共振成像处理技术，即将整个血氧水平依赖（BOLD）信号与标准模型相关联，并没有提取到生理上有意义的信号，这可能是由于腿部运动引起的磁场畸变所致。因此，我们只检查了无运动期间血氧水平依赖（BOLD）信号的部分。这项技术利用了BOLD信号的延迟特性，并在运动停止后用标准模型拟合信号的下降部分。使用这种方法，我们在初级和次级感觉运动皮层以及小脑中观察到了与踩踏板相关的生理上合理的大脑活动模式。据我们所知，这是首次使用功能磁共振成像记录与踩踏板相关的人类大脑活动。这项技术可能有助于增进我们对健康和疾病状态下类似运动的脊髓上控制的理解。
