A central pattern generator producing alternative outputs:: Temporal pattern of premotor activity
A central pattern generator producing alternative outputs:: Temporal pattern of premotor activity
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DOI：
10.1152/jn.00011.2006
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发表时间：
2006-07-01
影响因子：
2.5
通讯作者：
Calabrese, Ronald L.
中科院分区：
文献类型：
--
作者：
Norris, Brian J.;Weaver, Adam L.;Calabrese, Ronald L.
药用水蛭的心跳中央模式发生器由七对经鉴定的节段性心脏中间神经元组成。四对心脏中间神经元与节段性心脏运动神经元形成交错的抑制性突触连接。使用细胞外记录从多个中间神经元在网络中的56个孤立的神经索，我们表明，这种模式发生器产生一侧到另一侧的不对称模式的同侧运动前中间神经元之间的节段间协调。这种模式对应于心脏运动神经元中类似的不对称虚构运动模式和两个管状心脏的不对称收缩模式，同步和蠕动。我们提供了一个定量的描述所有的前运动中间神经元的放电模式，包括相位，占空比，和这个前运动活动模式的爆发内频率。这种分析确定了两个刻板的协调模式，对应于同步和蠕动，这表明在很宽的范围内的时期的相位恒定性一样，虚构的运动模式和心脏收缩模式。协调模式是通过一个节段对心脏中间神经元（开关中间神经元）控制的。协调模式中的侧到侧开关是该模式生成器的常规特征，并且随着这些开关中间神经元的活动状态的变化而发生。与前运动中间神经元的同步协调相关联，同侧开关中间神经元处于活跃状态，在此期间它产生有节奏的爆发，而与蠕动协调相关联，同侧开关中间神经元在很大程度上是沉默的。我们认为，时间和模式的阐述是独立的功能重叠的子网络中产生的心跳中央模式发生器。
The central pattern generator for heartbeat in medicinal leeches constitutes seven identified pairs of segmental heart interneurons. Four identified pairs of heart interneurons make a staggered pattern of inhibitory synaptic connections with segmental heart motor neurons. Using extracellular recording from multiple interneurons in the network in 56 isolated nerve cords, we show that this pattern generator produces a side-to-side asymmetric pattern of intersegmental coordination among ipsilateral premotor interneurons. This pattern corresponds to a similarly asymmetric fictive motor pattern in heart motor neurons and asymmetric constriction pattern of the two tubular hearts, synchronous and peristaltic. We provide a quantitative description of the firing pattern of all the premotor interneurons, including phase, duty cycle, and intraburst frequency of this premotor activity pattern. This analysis identifies two stereotypical coordination modes corresponding to synchronous and peristaltic, which show phase constancy over a broad range of periods as do the fictive motor pattern and the heart constriction pattern. Coordination mode is controlled through one segmental pair of heart interneurons ( switch interneurons). Side-to-side switches in coordination mode are a regular feature of this pattern generator and occur with changes in activity state of these switch interneurons. Associated with synchronous coordination of premotor interneurons, the ipsilateral switch interneuron is in an active state, during which it produces rhythmic bursts, whereas associated with peristaltic coordination, the ipsilateral switch interneuron is largely silent. We argue that timing and pattern elaboration are separate functions produced by overlapping subnetworks in the heartbeat central pattern generator.