Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, USA.
Clin Neurophysiol. 2010 Oct;121(10):1680-9. doi: 10.1016/j.clinph.2010.02.166.
The often studied stretch reflex is fundamental to the involuntary control of posture and movement. Nevertheless, there remains controversy regarding its functional role. Many studies have demonstrated that stretch reflexes can be modulated in a task appropriate manner. This review focuses on modulation of the long-latency stretch reflex, thought to be mediated, at least in part, by supraspinal pathways. For example, this component of the stretch reflex increases in magnitude during interactions with compliant environments, relative to its sensitivity during interactions with rigid environments. This suggests that reflex sensitivity increases to augment limb stability when that stability is not provided by the environment. However, not all results support the stabilizing role of stretch reflexes. Some studies have demonstrated that involuntary responses within the time period corresponding to the long-latency reflex can destabilize limb posture. We propose that this debate stems from the fact that multiple perturbation-sensitive pathways can contribute to the long-latency stretch reflex and that these pathways have separate functional roles. The presented studies suggest that neural activity occurring within the period normally ascribed to the long-latency stretch reflex is highly adaptable to current task demands and possibly should be considered more intelligent than "reflexive".
经常研究的牵张反射是姿势和运动无意识控制的基础。然而，其功能作用仍存在争议。许多研究表明，牵张反射可以以适当的方式进行调节。本篇综述聚焦于长潜伏期牵张反射的调节，该反射被认为至少部分是由脊髓上途径介导的。例如，与与刚性环境相互作用时相比，在与柔顺环境相互作用时，该反射的幅度增加。这表明当环境不能提供肢体稳定性时，反射敏感性会增加以增强肢体稳定性。然而，并非所有结果都支持牵张反射的稳定性作用。一些研究表明，在长潜伏期反射对应的时间段内，无意识的反应可能会破坏肢体姿势的稳定性。我们提出，这种争论源于这样一个事实，即多个对扰动敏感的途径可能会对长潜伏期牵张反射产生影响，并且这些途径具有不同的功能作用。所提出的研究表明，在通常归因于长潜伏期牵张反射的时间段内发生的神经活动对当前任务需求具有高度适应性，并且可能比“反射性”更具智能性。
