Motor learning of novel dynamics is not represented in a single global coordinate system: evaluation of mixed coordinate representations and local learning.
Motor learning of novel dynamics is not represented in a single global coordinate system: evaluation of mixed coordinate representations and local learning.
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DOI：
10.1152/jn.00493.2013
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发表时间：
2014-03
影响因子：
2.5
通讯作者：
Kording K
中科院分区：
文献类型：
--
作者：
Berniker M;Franklin DW;Flanagan JR;Wolpert DM;Kording K
成功的运动表现需要运动指令适应任务动态的能力。运动神经科学的一个中心问题是这些动力学是如何表现的。尽管广泛地假设动态（例如，力场）以内在的、基于关节的坐标表示（Shadmehr R，Mussa-Ivaldi FA. J Neurosci 14：3208-3224，1994），最近的证据质疑了这一提议。在这里，我们重新审查的动态表示在两个实验。通过测试泛化后的变化，肩膀，肘部，或手腕的配置，第一个实验测试外在，内在，或以对象为中心的表示。没有一个单一的坐标框架可以解释普遍化的模式。相反，泛化模式更好地解释了混合的表示或模型，假设本地学习和分级，衰减泛化。在第二个实验中，我们复制了一项有影响力的研究的设计，该研究建议在内在坐标中编码（Shadmehr和Mussa-Ivaldi 1994），产生了类似的结果。也就是说，我们无法找到动力学在单一坐标系中表示的证据。综上所述，我们的实验表明，内部模型在泛化时不使用单一坐标系，并且可以表示为坐标系的混合物，作为具有局部学习的单一系统，或者两者兼而有之。
Successful motor performance requires the ability to adapt motor commands to task dynamics. A central question in movement neuroscience is how these dynamics are represented. Although it is widely assumed that dynamics (e.g., force fields) are represented in intrinsic, joint-based coordinates (Shadmehr R, Mussa-Ivaldi FA. J Neurosci 14: 3208–3224, 1994), recent evidence has questioned this proposal. Here we reexamine the representation of dynamics in two experiments. By testing generalization following changes in shoulder, elbow, or wrist configurations, the first experiment tested for extrinsic, intrinsic, or object-centered representations. No single coordinate frame accounted for the pattern of generalization. Rather, generalization patterns were better accounted for by a mixture of representations or by models that assumed local learning and graded, decaying generalization. A second experiment, in which we replicated the design of an influential study that had suggested encoding in intrinsic coordinates (Shadmehr and Mussa-Ivaldi 1994), yielded similar results. That is, we could not find evidence that dynamics are represented in a single coordinate system. Taken together, our experiments suggest that internal models do not employ a single coordinate system when generalizing and may well be represented as a mixture of coordinate systems, as a single system with local learning, or both.
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影响因子：
56.9
作者：
GEORGOPOULOS, AP;LURITO, JT;MASSEY, JT
通讯作者：
MASSEY, JT
影响因子：
3.7
作者：
Kadiallah A;Franklin DW;Burdet E
通讯作者：
Burdet E
DOI：
10.1523/jneurosci.0273-11.2011
发表时间：
2011-05-11
期刊：
The Journal of neuroscience : the official journal of the Society for Neuroscience
影响因子：
--
作者：
Orban de Xivry JJ;Marko MK;Pekny SE;Pastor D;Izawa J;Celnik P;Shadmehr R
通讯作者：
Shadmehr R
DOI：
10.1073/pnas.93.9.3843
发表时间：
1996-04-30
影响因子：
11.1
作者：
Gandolfo, F;MussaIvaldi, FA;Bizzi, E
通讯作者：
Bizzi, E
影响因子：
25
作者：
Haswell, Courtney C.;Izawa, Jun;Dowell, Lauren R.;Mostofsky, Stewart H.;Shadmehr, Reza
通讯作者：
Shadmehr, Reza