Department of Neurobiology, Institute of Life Sciences and Interdisciplinary Center for Neuronal Computation, Hebrew University, Jerusalem 91904, Israel.
Curr Biol. 2009 Oct 13;19(19):1632-6. doi: 10.1016/j.cub.2009.07.067. Epub 2009 Sep 17.
Hyperredundant limbs with a virtually unlimited number of degrees of freedom (DOFs) pose a challenge for both biological and computational systems of motor control. In the flexible arms of the octopus, simplification strategies have evolved to reduce the number of controlled DOFs. Motor control in the octopus nervous system is hierarchically organized. A relatively small central brain integrates a huge amount of visual and tactile information from the large optic lobes and the peripheral nervous system of the arms and issues commands to lower motor centers controlling the elaborated neuromuscular system of the arms. This unique organization raises new questions on the organization of the octopus brain and whether and how it represents the rich movement repertoire. We developed a method of brain microstimulation in freely behaving animals and stimulated the higher motor centers-the basal lobes-thus inducing discrete and complex sets of movements. As stimulation strength increased, complex movements were recruited from basic components shared by different types of movement. We found no stimulation site where movements of a single arm or body part could be elicited. Discrete and complex components have no central topographical organization but are distributed over wide regions.
具有几乎无限自由度 (DOFs) 的超冗余肢体给生物和计算运动控制系统都带来了挑战。在章鱼的灵活手臂中，已经进化出简化策略来减少受控 DOFs 的数量。章鱼神经系统中的运动控制是层次化组织的。相对较小的中央大脑整合了来自大视神经叶和手臂周围神经系统的大量视觉和触觉信息，并向控制手臂复杂神经肌肉系统的较低运动中心发出命令。这种独特的组织提出了关于章鱼大脑的组织以及它是否以及如何表示丰富的运动曲目等新问题。我们开发了一种在自由行为动物中进行大脑微刺激的方法，并刺激较高的运动中心——基底叶——从而诱导离散和复杂的运动集合。随着刺激强度的增加，复杂的运动由不同类型运动共享的基本组件组成。我们没有发现可以引起单个手臂或身体部位运动的刺激部位。离散和复杂的组件没有中央拓扑组织，而是分布在广泛的区域。
