Reorganization of brain activity for multiple internal models after short but intensive training
Reorganization of brain activity for multiple internal models after short but intensive training
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DOI：
10.1016/s0010-9452(08)70459-3
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发表时间：
2007-04-01
期刊：
影响因子：
3.6
通讯作者：
Kawato, Mitsuo
中科院分区：
文献类型：
--
作者：
Imamizu, Hiroshi;Higuchi, Satomi;Kawato, Mitsuo
内部模型是可以模仿受控对象的输入输出特性的神经机制。我们的研究表明：1）在小脑中获得了新工具的内部模型（Imamizu et al., 2000）； 2）内部模型在小脑中模块化组织（Imamizu et al., 2003）； 3）学习后它们的输出被发送到运动前区域（Tamada et al., 1999）； 4）前额叶和顶叶区域有助于输出的混合（Imamizu et al., 2004）。在这里，我们研究了由于获取新的内部模型而导致的全局神经网络的变化。人类受试者操纵三种类型的旋转操纵杆，其光标出现在围绕屏幕中心旋转 60 度、110 度或 160 度的位置。在对 60 度和 160 度操纵杆进行长期训练（5 天）后的预测试中，在操作三个操纵杆期间扫描了大脑激活情况。然后受试者仅接受 25 分钟的 110 度训练。在后测试中，使用与前测试相同的方法扫描激活。测试后与测试前的比较表明，在观察到三个旋转的激活的大多数区域中，激活量有所减少。然而，仅在下外侧小脑和 110 度操纵杆中，体积略有显着增加 (p < .08)。在大脑皮层中，前额叶和顶叶区域与 110 度相关的激活减少，但运动前区和辅助运动区 (SMA) 区域的激活增加。这些结果可以用一个模型来解释，在该模型中，60 度和 160 度内部模型的输出通过前额叶和顶叶区域混合，以在 25 分钟训练之前应对新颖的 110 度操纵杆；在小脑内采集 110 度的内部模型后，输出直接发送到前运动和 SMA 区域，并且这些区域的激活增加。
Internal models are neural mechanisms that can mimic the input-output properties of controlled objects. Our studies have shown that: 1) an internal model for a novel tool is acquired in the cerebellum (Imamizu et al., 2000); 2) internal models are modularly organized in the cerebellum (Imamizu et al., 2003); 3) their outputs are sent to the premotor regions after learning (Tamada et al., 1999); and 4) the prefrontal and parietal regions contribute to the blending of the outputs (Imamizu et al., 2004). Here, we investigated changes in global neural networks resulting from the acquisition of a new internal model. Human subjects manipulated three types of rotating joystick whose cursor appeared at a position rotated 60 degrees, 110 degrees, or 160 degrees around the screen's center. In a pre-test after long-term training (5 days) for the 60 degrees and 160 degrees joysticks, brain activation was scanned during manipulation of the three joysticks. The subjects were then trained for the 110 degrees for only 25 min. In a post-test, activation was scanned using the same method as the pre-test. Comparisons of the post-test to the pre-test revealed that the volume of activation decreased in most of the regions where activation for the three rotations was observed. However, there was an increase in volume at a marginally significant level (p < .08) only in the inferior-lateral cerebellum and only for the 110 degrees joystick. In the cerebral cortex, activation related to 110 degrees decreased in the prefrontal and parietal regions but increased in the premotor and supplementary motor area (SMA) regions. These results can be explained by a model in which outputs of the 60 degrees and 160 degrees internal models are blended by prefrontal and parietal regions to cope with the novel 110 degrees joystick before the 25-minute training; after the acquisition within the cerebellum of an internal model for the 110 degrees, output is directly sent to the premotor and SMA regions, and activation in these regions increases.