Dual-mode operation of neuronal networks involved in left-right alternation
Dual-mode operation of neuronal networks involved in left-right alternation
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DOI：
10.1038/nature12286
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发表时间：
2013-08-01
期刊：
影响因子：
64.8
通讯作者：
Kiehn, Ole
中科院分区：
文献类型：
--
作者：
Talpalar, Adolfo E.;Bouvier, Julien;Kiehn, Ole
所有形式的运动都是重复的运动活动，需要协调的双侧肌肉激活。运动控制的执行元件是脊髓神经元网络，其通过体轴两侧运动神经元池的顺序激活来确定步态模式（1-4）。然而，人们对左右协调与运动速度之间的关系知之甚少。最近的进展表明，兴奋性和抑制性连合神经元都可能参与左右协调（5-7）。但是这种现象的神经基础，以及这些不同的连合神经元群和左右交替之间可能的因果关系，都是缺乏的。在这里，我们表明，使用交叉小鼠遗传学，消融一组转录定义连合神经元的V0人口导致四足跳跃在所有频率的运动。选择性消融抑制性V0神经元导致低频时左右模式缺失，中频时混合协调，高频时交替运动。当消融的目标是兴奋性V0神经元，左-右交替是目前在低频率，和跳跃被限制在中等和高运动频率。因此，运动的中央控制的内在逻辑结合了一个模块化的组织，需要两个V0神经元的子组，以不同的运动速度存在左右交替模式。这两组分子上不同的连合神经元可能会限制物种相关的自然发生的频率依赖性协调，并参与不同步态的进化。
All forms of locomotion are repetitive motor activities that require coordinated bilateral activation of muscles. The executive elements of locomotor control are networks of spinal neurons that determine gait pattern through the sequential activation of motor-neuron pools on either side of the body axis(1-4). However, little is known about the constraints that link left-right coordination to locomotor speed. Recent advances have indicated that both excitatory and inhibitory commissural neurons may be involved in left-right coordination(5-7). But the neural underpinnings of this, and a possible causal link between these different groups of commissural neurons and left-right alternation, are lacking. Here we show, using intersectional mouse genetics, that ablation of a group of transcriptionally defined commissural neurons-the V0 population-leads to a quadrupedal hopping at all frequencies of locomotion. The selective ablation of inhibitory V0 neurons leads to a lack of left-right pattern at low frequencies, mixed coordination at medium frequencies, and alternation at high locomotor frequencies. When ablation is targeted to excitatory V0 neurons, left-right alternation is present at low frequencies, and hopping is restricted to medium and high locomotor frequencies. Therefore, the intrinsic logic of the central control of locomotion incorporates a modular organization, with two subgroups of V0 neurons required for the existence of left-right alternating modes at different speeds of locomotion. The two molecularly distinct sets of commissural neurons may constrain species-related naturally occurring frequency-dependent coordination and be involved in the evolution of different gaits.