Parmar Pritesh N, Huang Felix C, Patton James L
University of Illinois at Chicago, Chicago, IL 60607, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:6762-8. doi: 10.1109/IEMBS.2011.6091668.
It has been widely accepted that the CNS develops a representation (model) of the environment, but what is not entirely clear is the coordinate reference frame used. We explored how visual feedback influenced the coordinate frame in which the CNS stores and recalls these memories of learned skills in a reaching-generalization task. Four groups of subjects trained to perform reaching movements in a perturbing force field, two with aligned (first person) visual feedback and two with non-aligned (vertical screen). After 170 trials of practice, we asked subjects to extrapolate (generalize) what they learned to a new part of the workspace in novel force environments (endpoint-based versus joint-based extrapolated force fields). Regardless of the test condition, all subjects improved their ability to generalize skills to the new workspace. There was evidence that the extrapolation of their learned skills was based on both object-centered and joint-based coordinates. Consistent with previous studies, subjects performed significantly better in joint-extrapolated force field, but only if the visual feedback was vertical. Subjects performed equivalently in both force fields with aligned (first person) feedback. These findings suggest that the type of visual feedback biases the way subjects perform, and that learning results can be significantly influenced by feedback.
人们普遍认为中枢神经系统会形成一种环境表征（模型），但尚不完全清楚所使用的坐标参考系是什么。我们在一项伸手够物泛化任务中探究了视觉反馈如何影响中枢神经系统存储和回忆这些习得技能记忆时所使用的坐标框架。四组受试者接受训练，在一个有干扰力场的环境中进行伸手够物动作，其中两组有对齐的（第一人称视角）视觉反馈，另外两组有未对齐的（垂直屏幕）视觉反馈。经过170次练习试验后，我们要求受试者将他们所学的内容外推（泛化）到新的力环境下工作空间的新区域（基于端点的与基于关节的外推力场）。无论测试条件如何，所有受试者将技能泛化到新工作空间的能力都有所提高。有证据表明，他们所学技能的外推是基于以物体为中心和以关节为基础的坐标。与之前的研究一致，受试者在关节外推力场中的表现明显更好，但前提是视觉反馈是垂直的。在有对齐的（第一人称视角）反馈的情况下，受试者在两种力场中的表现相当。这些发现表明，视觉反馈的类型会影响受试者的表现方式，并且学习结果会受到反馈的显著影响。
