Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
J Neurophysiol. 2019 Sep 1;122(3):922-932. doi: 10.1152/jn.00756.2018. Epub 2019 Jun 26.
Active sensing in biological system consists of emitting/receiving a periodic signal to explore the environment. The signal can be emitted toward distant objects, as in echolocation, or in direct contact with the object, for example, whisking in rodents. We explored the hypothesis that a similar mechanism exists in humans. Humans generate periodic signals at ~10 Hz during voluntary finger movements, which reflects a pulsatile motor command in the central nervous system. In the present study, we tested whether the ~10-Hz signal persists during the active exploration of textures and whether the textures' features can modulate the signal. Our results confirm our assumptions. The ~10-Hz signal persisted during active touch, and its amplitude increased with textures of higher friction. These findings support the idea that the ~10-Hz periodic signal generated during voluntary finger movements is part of an active sensing mechanism acting in a pulse-amplitude modulation fashion to convey relevant tactile information to the brain. For the first time, we show that pulsatile motor output during voluntary movement of a finger persists during active exploration of a surface. We propose that this is part of an active sensing system in humans, with generation of an ~10-Hz signal during active touch that reinforces extraction of information about features of the touched surface.
主动感知生物系统包括发射/接收周期性信号以探索环境。信号可以发射到远处的物体，如回声定位，也可以直接与物体接触，例如啮齿动物的胡须。我们探讨了这样一种假设，即在人类中也存在类似的机制。人类在自愿进行手指运动时会产生约 10 Hz 的周期性信号，这反映了中枢神经系统中脉动的运动指令。在本研究中，我们测试了在主动探索纹理时，约 10 Hz 的信号是否持续存在，以及纹理的特征是否可以调制该信号。我们的结果证实了我们的假设。在主动触摸时，约 10 Hz 的信号持续存在，并且其幅度随着摩擦更高的纹理而增加。这些发现支持这样一种观点，即在自愿手指运动中产生的约 10 Hz 周期性信号是一种主动感知机制的一部分，该机制以脉冲幅度调制的方式将相关的触觉信息传递给大脑。我们首次表明，在手指主动探索表面时，自愿运动期间的脉动电机输出持续存在。我们提出，这是人类主动感知系统的一部分，在主动触摸时会产生约 10 Hz 的信号，从而增强了对所触及表面特征的信息提取。
