Presynaptic inhibition of spinal sensory feedback ensures smooth movement.
Presynaptic inhibition of spinal sensory feedback ensures smooth movement.
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作者：
熟练动作的精确度取决于感觉反馈及其通过局部抑制微电路的细化。一组专门的脊髓GABA能中间神经元与感觉传入的中枢末梢形成轴-轴接触，对感觉-运动传递施加突触前抑制控制。由于无法实现选择性地进入负责这种非正统抑制机制的GABA能神经元，突触前抑制对运动行为的贡献尚未得到解决。我们使用Gad 2作为遗传切入点来操纵与感觉末梢接触的中间神经元，并表明小鼠中这些中间神经元的激活激发了突触前抑制的定义生理特征。Gad 2表达的中间神经元的选择性基因消融严重干扰了目标导向的到达运动，揭示了一个明显的和刻板的前肢运动振荡，其核心特征是通过模拟高增益的感觉反馈的后果来捕获的。我们的研究结果定义了一个基因硬连线增益控制系统的神经基板的运动的顺利执行至关重要。
The precision of skilled movement depends on sensory feedback and its refinement by local inhibitory microcircuits. One specialized set of spinal GABAergic interneurons forms axo-axonic contacts with the central terminals of sensory afferents, exerting presynaptic inhibitory control over sensory-motor transmission. The inability to achieve selective access to the GABAergic neurons responsible for this unorthodox inhibitory mechanism has left unresolved the contribution of presynaptic inhibition to motor behavior. We used Gad2 as a genetic entry point to manipulate the interneurons that contact sensory terminals, and show that activation of these interneurons in mice elicits the defining physiological characteristics of presynaptic inhibition. Selective genetic ablation of Gad2-expressing interneurons severely perturbs goal-directed reaching movements, uncovering a pronounced and stereotypic forelimb motor oscillation, the core features of which are captured by modeling the consequences of sensory feedback at high gain. Our findings define the neural substrate of a genetically hard-wired gain control system crucial for the smooth execution of movement.
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影响因子：
2.5
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Churchland, MM;Lisberger, SG
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