Department of Physiology and Pharmacology, Western University, London, ON, Canada.
Department of Physiology and Pharmacology, Western University, London, ON, Canada.
Curr Biol. 2020 Sep 21;30(18):R1025-R1030. doi: 10.1016/j.cub.2020.07.092.
Many of us know about stretch reflexes from the doctor's office, when a physician taps the tendon near our kneecap to elicit a quick knee extension. This procedure is used as a diagnostic tool to determine the integrity of the spinal cord and the extension response it elicits may seem otherwise useless. In fact, the tendon tap taps into one aspect of a critical building block of mammalian motor control, the stretch reflexes. Stretch reflexes are often thought to quickly resist unexpected changes in muscle length via a very simple circuit in the spinal cord, and this is one circuit that the tendon tap engages. It turns out, however, that stretch reflexes support a myriad of functions and are highly flexible. Under naturalistic conditions, stretch reflexes are shaped by peripheral physiology and engage neural circuits spanning the spinal cord, brainstem and cerebral cortex. In this Primer, we outline what is currently known about stretch reflex function and its underlying mechanisms, with a specific focus on how the cascade of nested responses collectively known as stretch reflexes interact with and build off of one another to support real-world motor behavior.
我们许多人从医生办公室了解到牵张反射，当医生敲击我们膝盖骨附近的肌腱以引起快速的膝盖伸展时。这个过程被用作诊断工具，以确定脊髓的完整性，并且它引起的伸展反应似乎没有用。事实上，肌腱敲击触及了哺乳动物运动控制的一个关键组成部分的一个方面，即牵张反射。牵张反射通常被认为通过脊髓中的一个非常简单的电路快速抵抗肌肉长度的意外变化，而这正是肌腱敲击所涉及的一个电路。然而，事实证明，牵张反射支持着无数的功能，并且具有高度的灵活性。在自然条件下，牵张反射受外周生理学的影响，并涉及跨越脊髓、脑干和大脑皮层的神经回路。在这篇概述中，我们概述了目前已知的牵张反射功能及其潜在机制，特别关注被称为牵张反射的嵌套反应级联如何相互作用并相互构建，以支持现实世界的运动行为。
