Imaging and brain stimulation studies seem to correct the classical understanding of how brain networks, rather than contralateral focal areas, control the generation of unimanual voluntary force. However, the scaling and hemispheric-specificity of network activation remain less understood. Using fMRI, we examined the effects of parametrically increasing right-handgrip force on activation and functional connectivity among the sensorimotor network bilaterally with 25%, 50%, and 75% maximal voluntary contractions (MVC). High force (75% MVC) unimanual handgrip contractions resulted in greater ipsilateral motor activation and functional connectivity with the contralateral hemisphere compared to a low force 25% MVC condition. The ipsilateral motor cortex activation and network strength correlated with relative handgrip force (% MVC). Increases in unimanual handgrip force resulted in greater ipsilateral sensorimotor activation and greater functional connectivity between hemispheres within the sensorimotor network.

影像学和大脑刺激研究似乎纠正了关于大脑网络而不是对侧焦点区域如何控制单手自愿力量生成的经典理解。但是，对网络激活的规模和半球特异性仍知之甚少。使用功能磁共振成像，我们检查了参数的右手抓力对激活和两侧感觉运动网络之间的主动连接和功能连接的影响，最大自发性收缩（MVC）分别为25％，50％和75％。与低力25％MVC相比，高力（75％MVC）的单手握力收缩会导致同侧半球的同侧运动激活和功能连接性增强。同侧运动皮层的激活和网络强度与相对握力（％MVC）相关。