Gandevia Simon C, Fisher Georgia, Diong Joanna, Butler Annie A, Héroux Martin E
Neuroscience Research Australia, Randwick, New South Wales, Australia.
University of New South Wales, Sydney, New South Wales, Australia.
Exp Physiol. 2025 Oct;110(10):1447-1456. doi: 10.1113/EP092686. Epub 2025 Jun 10.
Proprioceptive judgements can be divided into two broad categories: low-level and high-level. Low-level judgements of limb position require a person to detect, discriminate or match the position of a body part, whereas high-level judgements require a person to report the position of an unseen body part relative to the external world. It has been suggested that muscle thixotropy - the influence of recent contraction or stretch on the passive properties of a muscle - impacts both the accuracy of low-level judgements of limb position and the degree to which these judgements drift over time. However, high-level proprioceptive judgements of upper limb position and the degree to which they drift over time may not be affected by thixotropy. This was investigated here. Twenty-five healthy adult participants made visual judgements about the perceived position of their hidden index finger after their elbow muscles had been conditioned with a flexion or extension contraction, or after a series of large passive elbow movements. After conditioning contractions, participants made small errors (∼2°) in perceived index finger position in the direction of elbow flexion, regardless of the contraction type. There was little to no effect of either contraction type on drift in perceived index-finger position in our test. Our results support the view that high-level proprioceptive judgements of hand position can be minimally affected by the effects of muscle thixotropy. Thus, we suggest that muscle spindle signals do not dominate the central, cross-modal transformations of sensory information that are required for high-level proprioceptive judgements.
低层次和高层次。肢体位置的低层次判断要求个体检测、辨别或匹配身体部位的位置，而高层次判断则要求个体报告一个看不见的身体部位相对于外部世界的位置。有人提出，肌肉触变性——近期收缩或伸展对肌肉被动特性的影响——会影响肢体位置低层次判断的准确性以及这些判断随时间推移的漂移程度。然而，上肢位置的高层次本体感觉判断及其随时间推移的漂移程度可能不受触变性的影响。本文对此进行了研究。25名健康成年参与者在其肘部肌肉进行屈曲或伸展收缩训练后，或在进行一系列大幅度被动肘部运动后，对其隐藏食指的感知位置进行视觉判断。在进行收缩训练后，无论收缩类型如何，参与者在感知食指位置时都会在肘部屈曲方向出现小的误差（约2°）。在我们的测试中，收缩类型对感知食指位置的漂移几乎没有影响。我们的结果支持这样一种观点，即手部位置的高层次本体感觉判断受肌肉触变性的影响最小。因此，我们认为肌梭信号在高层次本体感觉判断所需的感觉信息的中枢跨模态转换中并不占主导地位。
