The same core rhythm generator underlies different rhythmic motor patterns.
The same core rhythm generator underlies different rhythmic motor patterns.
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DOI：
10.1523/jneurosci.1885-11.2011
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发表时间：
2011-08-10
期刊：
影响因子：
--
通讯作者：
Nusbaum MP
中科院分区：
文献类型：
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作者：
White RS;Nusbaum MP
有节奏地活动的运动回路可以响应于不同的输入而产生不同的活动模式。然而，在大多数系统中，我们并不知道是否是相同的神经元为每种不同的模式产生了潜在的节奏。到目前为止，关于节律发生器神经元的保守程度的信息仅限于少数起搏器驱动的电路，其中大多数核心节律发生器在不同的输出模式中是不变的。我们正在解决这个问题的网络驱动，胃磨（咀嚼）电路在螃蟹口胃神经系统。我们首先建立了不同的胃磨电机模式触发两个外在的输入途径，腹心神经元（VCN）和食管后连合（POC）神经元的单独刺激。区分这些胃磨运动模式的突出特征是LG量角器运动神经元活动模式，其在VCN节律期间是紧张性的，并且在POC节律期间表现出快速节律爆发。这两种运动模式在其周期和一些运动神经元相位关系、占空比和爆发持续时间方面也不同。尽管POC-和VCN-运动模式是不同的，在每个运动模式期间的节律产生需要相同的两个抑制性胃磨神经元的活动（LG，Int 1）。具体而言，可逆超极化LG或Int 1，但没有其他胃磨神经元，延迟下一个胃磨周期的开始，直到施加超极化后。因此，在网络驱动的节律运动模式的不同版本期间，相同的电路神经元可以包括核心节律发生器。
Rhythmically active motor circuits can generate different activity patterns in response to different inputs. In most systems, however, it is not known whether the same neurons generate the underlying rhythm for each different pattern. Thus far, information regarding the degree of conservation of rhythm generator neurons is limited to a few pacemaker-driven circuits, in most of which the core rhythm generator is unchanged across different output patterns. We are addressing this issue in the network-driven, gastric mill (chewing) circuit in the crab stomatogastric nervous system. We first establish that distinct gastric mill motor patterns are triggered by separate stimulation of two extrinsic input pathways, the ventral cardiac neurons (VCNs) and post-oesophageal commissure (POC) neurons. A prominent feature that distinguishes these gastric mill motor patterns is the LG protractor motor neuron activity pattern, which is tonic during the VCN-rhythm and exhibits fast rhythmic bursting during the POC-rhythm. These two motor patterns also differed in their cycle period and some motor neuron phase relationships, duty cycles and burst durations. Despite the POC- and VCN-motor patterns being distinct, rhythm generation during each motor pattern required the activity of the same two, reciprocally inhibitory gastric mill neurons (LG, Int1). Specifically, reversibly hyperpolarizing LG or Int1, but no other gastric mill neuron, delayed the start of the next gastric mill cycle until after the imposed hyperpolarization. Thus, the same circuit neurons can comprise the core rhythm generator during different versions of a network-driven rhythmic motor pattern.