Even-Skipped+ Interneurons Are Core Components of a Sensorimotor Circuit that Maintains Left-Right Symmetric Muscle Contraction Amplitude
Even-Skipped+ Interneurons Are Core Components of a Sensorimotor Circuit that Maintains Left-Right Symmetric Muscle Contraction Amplitude
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DOI：
10.1016/j.neuron.2015.09.009
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发表时间：
2015-10-21
期刊：
影响因子：
16.2
通讯作者：
Doe, Chris Q.
中科院分区：
文献类型：
--
作者：
Heckscher, Ellie S.;Zarin, Aref Arzan;Doe, Chris Q.
左右对称的运动模式--左右成对的肌肉以相同的幅度同步收缩（如呼吸、微笑、摇动和运动）--在动物王国中广泛存在。然而，令人惊讶的是，人们对潜在的神经回路知之甚少。我们进行了一个产热筛选，以确定果蝇幼虫双侧对称运动所需的神经元，并确定了进化上保守的偶数跳过（+）中间神经元（Eve/Evx）。Eve（+）中间神经元的激活或消融破坏了双侧对称的肌肉收缩幅度，而不影响运动输出的时间。Eve（+）中间神经元没有节律性活动，因此独立于运动CPG发挥作用。自由活动幼虫Eve（+）中间神经元的GCaMP 6钙成像显示左右不对称激活，与幼虫行为相关。Eve（+）中间神经元输入和输出的TEM重建表明，Eve（+）中间神经元是能够检测和修改体壁肌肉收缩的感觉运动回路的核心。
Bilaterally symmetric motor patterns-those in which left-right pairs of muscles contract synchronously and with equal amplitude (such as breathing, smiling, whisking, and locomotion)-are widespread throughout the animal kingdom. Yet, surprisingly little is known about the underlying neural circuits. We performed a thermogenetic screen to identify neurons required for bilaterally symmetric locomotion in Drosophila larvae and identified the evolutionarily conserved Even-skipped(+) interneurons (Eve/Evx). Activation or ablation of Eve(+) interneurons disrupted bilaterally symmetric muscle contraction amplitude, without affecting the timing of motor output. Eve(+) interneurons are not rhythmically active and thus function independently of the locomotor CPG. GCaMP6 calciumimaging of Eve(+) interneurons in freely moving larvae showed left-right asymmetric activation that correlated with larval behavior. TEM reconstruction of Eve(+) interneuron inputs and outputs showed that the Eve(+) interneurons are at the core of a sensorimotor circuit capable of detecting and modifying body wall muscle contraction.