...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Neurophysiology >Reference frames for spinal proprioception: limb endpoint based or joint-level based?
【24h】

Reference frames for spinal proprioception: limb endpoint based or joint-level based?

机译：脊椎本体感受的参考系：基于肢端终点还是基于关节水平？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Many sensorimotor neurons in the CNS encode global parameters of limb movement and posture rather than specific muscle or joint parameters. Our investigations of spinocerebellar activity have demonstrated that these second-order spinal neurons also may encode proprioceptive information in a limb-based rather than joint-based reference frame. However, our finding that each foot position was determined by a unique combination of joint angles in the passive limb made it difficult to distinguish unequivocally between a limb-based and a joint-based representation. In this study, we decoupled foot position from limb geometry by applying mechanical constraints to individual hindlimb joints in anesthetized cats. We quantified the effect of the joint constraints on limb geometry by analyzing joint-angle covariance in the free and constrained conditions. One type of constraint, a rigid constraint of the knee angle, both changed the covariance pattern and significantly reduced the strength of joint-angle covariance. The other type, an elastic constraint of the ankle angle, changed only the covariance pattern and not its overall strength. We studied the effect of these constraints on the activity in 70 dorsal spinocerebellar tract (DSCT) neurons using a multivariate regression model, with limb axis length and orientation as predictors of neuronal activity. This model also included an experimental condition indicator variable that allowed significant intercept or slope changes in the relationships between foot position parameters and neuronal activity to be determined across conditions. The result of this analysis was that the spatial tuning of 37/70 neurons (53%) was unaffected by the constraints, suggesting that they were somehow able to signal foot position independently from the specific joint angles. We also investigated the extent to which cell activity represented individual joint angles by means of a regression model based on a linear combination of joint angles. A backward elimination of the insignificant predictors determined the set of independent joint angles that best described the neuronal activity for each experimental condition. Finally, by comparing the results of these two approaches, we could determine whether a DSCT neuron represented foot position, specific joint angles, or none of these variables consistently. We found that 10/70 neurons (14%) represented one or more specific joint-angles. The activity of another 27 neurons (39%) was significantly affected by limb geometry changes, but 33 neurons (47%) consistently elaborated a foot position representation in the coordinates of the limb axis.
机译：中枢神经系统中的许多感觉运动神经元编码肢体运动和姿势的整体参数，而不是特定的肌肉或关节参数。我们对小脑脊髓活动的研究表明，这些二阶脊髓神经元也可能在基于肢体而不是基于关节的参照系中编码本体感受信息。但是，我们的发现，每个脚的位置都由被动肢中关节角度的唯一组合确定，因此很难明确地区分基于肢体的关节和基于关节的表征。在这项研究中，我们通过对麻醉猫的各个后肢关节施加机械约束，使脚部位置与肢体几何形状分离。通过分析自由和约束条件下的关节角度协方差，我们量化了关节约束对肢体几何形状的影响。一种约束类型，即膝盖角度的刚性约束，既改变了协方差模式，又显着降低了关节角协方差的强度。另一种是脚踝角度的弹性约束，仅改变了协方差模式，而没有改变其整体强度。我们使用多元回归模型，以肢体轴的长度和方向作为神经元活动的预测因子，研究了这些约束条件对70个背小脑脊髓神经元（DSCT）神经元活动的影响。该模型还包括一个实验条件指示器变量，该变量允许在各种条件下确定脚位置参数与神经元活动之间关系的显着截距或斜率变化。该分析的结果是，对37/70个神经元（53％）的空间调整不受约束的影响，表明它们能够以某种方式独立于特定的关节角度来发出脚的位置信号。我们还通过基于关节角线性组合的回归模型，研究了细胞活性代表各个关节角的程度。向后消除无关紧要的预测因素确定了独立关节角度的集合，该角度最能描述每种实验条件下的神经元活动。最后，通过比较这两种方法的结果，我们可以确定DSCT神经元是代表脚的位置，特定的关节角度还是始终代表这些变量。我们发现10/70个神经元（占14％）代表一个或多个特定的关节角。肢体几何形状变化显着影响了另外27个神经元（39％）的活动，但是33个神经元（47％）始终在肢体轴的坐标中完善了脚的位置表示。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号