Priors engaged in long-latency responses to mechanical perturbations suggest a rapid update in state estimation.
Priors engaged in long-latency responses to mechanical perturbations suggest a rapid update in state estimation.
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DOI：
10.1371/journal.pcbi.1003177
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发表时间：
2013
影响因子：
4.3
通讯作者：
Scott SH
中科院分区：
文献类型：
--
作者：
Crevecoeur F;Scott SH
在每一项运动任务中，我们的大脑都必须处理作用在身体上的外力。例如，在鹅卵石上骑自行车或在不规则的表面上滑冰需要我们对外部扰动做出适当的反应。在这些情况下，运动预测不能帮助预测由外部因素引起的身体运动，直接使用延迟的感觉反馈往往会产生不稳定性。在这里，我们表明，为了解决这个问题，运动系统使用快速的感官预测，以纠正估计的肢体状态。我们使用了一个姿势任务与机械扰动，以解决感觉预测是否从事上肢矫正运动。受试者改变了他们的初始运动反应在1060毫秒，这取决于预期的扰动配置文件，建议使用内部模型，或之前，在这个纠正过程。此外，我们发现审判的纠正反应的变化表明这些扰动先验的快速更新。我们使用了一个基于卡尔曼滤波的计算模型，表明响应调制与反馈响应中估计状态的快速校正是兼容的。这样的过程可能使我们能够处理几乎所有身体活动中遇到的外部干扰，这可能是熟练运动行为的重要特征。通常认为，大脑使用对身体状态的内部估计来调整运动命令并执行成功的运动。当外部干扰使肢体偏离正在进行的任务时，就会出现问题。在这种情况下，身体的估计状态必须基于感觉反馈来校正。由于神经传输延迟会使反馈控制不稳定，因此电机系统的一个重要挑战是尽可能快地校正估计的状态。在本文中，我们测试了是否进行这样的快速校正施加到上肢的机械负荷。我们的研究结果表明，长潜伏期的反应（100 - 50-100毫秒）表现出的延迟感测关节位移和当前状态的肢体在运动反应的发作之间的关系的知识。重要的是，这种知识可以从一个扰动响应调整到下一个，应该经历一个不同的扰动分布。这些结果表明，在肢体快速反馈通路内进行状态估计的校正，从而允许快速且稳定的反馈控制。
In every motor task, our brain must handle external forces acting on the body. For example, riding a bike on cobblestones or skating on irregular surface requires us to appropriately respond to external perturbations. In these situations, motor predictions cannot help anticipate the motion of the body induced by external factors, and direct use of delayed sensory feedback will tend to generate instability. Here, we show that to solve this problem the motor system uses a rapid sensory prediction to correct the estimated state of the limb. We used a postural task with mechanical perturbations to address whether sensory predictions were engaged in upper-limb corrective movements. Subjects altered their initial motor response in ∼60 ms, depending on the expected perturbation profile, suggesting the use of an internal model, or prior, in this corrective process. Further, we found trial-to-trial changes in corrective responses indicating a rapid update of these perturbation priors. We used a computational model based on Kalman filtering to show that the response modulation was compatible with a rapid correction of the estimated state engaged in the feedback response. Such a process may allow us to handle external disturbances encountered in virtually every physical activity, which is likely an important feature of skilled motor behaviour. It is commonly assumed that the brain uses internal estimates of the state of the body to adjust motor commands and perform successful movements. A problem arises when external disturbances deviate the limb from the ongoing task. In such cases, the estimated state of the body must be corrected based on sensory feedback. Because neural transmission delays can destabilize feedback control, an important challenge for motor systems is to correct the estimated state as quickly as possible. In this paper, we tested whether such a rapid correction is performed following mechanical loads applied to the upper limb. Our results indicate that long latency responses (∼50–100 ms) exhibit knowledge of the relationship between the delayed sensed joint displacement and the current state of the limb at the onset of the motor response. Importantly, this knowledge can be adjusted from one perturbation response to the next, should a distinct perturbation profile be experienced. These results suggest that a correction of state estimation is performed within the limb rapid-feedback pathways, allowing fast and stable feedback control.
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DOI：
10.1523/jneurosci.0061-07.2007
发表时间：
2007-06-06
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Diedrichsen J;Criscimagna-Hemminger SE;Shadmehr R
通讯作者：
Shadmehr R
影响因子：
2.5
作者：
Bennett, Simon J.;de Xivry, Jean-Jacques Orban;Lefevre, Philippe
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Lefevre, Philippe
影响因子：
5.3
作者：
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Edin, Benoni B.
DOI：
10.1523/jneurosci.3075-08.2009
发表时间：
2009-05-20
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Braun DA;Aertsen A;Wolpert DM;Mehring C
通讯作者：
Mehring C
影响因子：
1.9
作者：
Bhushan, N;Shadmehr, R
通讯作者：
Shadmehr, R