ISPA - Instituto Universitário, William James Center for Research, Lisboa, Portugal.
Sci Rep. 2019 Dec 10;9(1):18737. doi: 10.1038/s41598-019-55029-6.
Time perception relies on the motor system. Involves core brain regions of this system, including those associated with feelings generated from sensorimotor states. Perceptual timing is also distorted when movement occurs during timing tasks, possibly by interfering with sensorimotor afferent feedback. However, it is unknown if the perception of time is an active process associated with specific patterns of muscle activity. We explored this idea based on the phenomenon of electromyographic gradients, which consists of the dynamic increase of muscle activity during cognitive tasks that require sustained attention, a critical function in perceptual timing. We aimed to determine whether facial muscle dynamic activity indexes the subjective representation of time. We asked participants to judge stimuli durations (varying in familiarity) while we monitored the time course of the activity of the zygomaticus-major and corrugator-supercilii muscles, both associated with cognitive and affective feelings. The dynamic electromyographic activity in corrugator-supercilii over time reflected objective time and this relationship predicted subjective judgments of duration. Furthermore, the zygomaticus-major muscle signaled the bias that familiarity introduces in duration judgments. This suggests that subjective duration could be an embodiment process based in motor information changing over time and their associated feelings.
时间感知依赖于运动系统。该系统涉及核心脑区，包括与感觉运动状态产生的感觉相关的脑区。在进行计时任务时，如果发生运动，感知时间会发生扭曲，这可能是因为运动感觉传入反馈受到干扰。然而，目前尚不清楚时间感知是否是一种与特定肌肉活动模式相关的主动过程。我们基于肌电图梯度现象探讨了这一观点，该现象包括在需要持续注意力的认知任务中肌肉活动的动态增加，这是感知时间的关键功能。我们旨在确定面部肌肉的动态活动是否可以作为时间的主观表现指标。我们要求参与者在监测颧大肌和皱眉肌活动的时间进程的同时判断刺激持续时间（熟悉度不同），这两种肌肉都与认知和情感感觉有关。皱眉肌的动态肌电图活动随时间的变化反映了客观时间，这种关系可以预测持续时间的主观判断。此外，颧大肌的活动表明熟悉度会对持续时间判断产生偏差。这表明，主观持续时间可能是一种基于随时间变化的运动信息及其相关感觉的体现过程。
