Wolf Ervin, Soffe S R, Roberts Alan
Department of Anatomy, Histology and Embryology, Faculty of Medicine, Medical and Health Science Center, University of Debrecen, Nagyerdei krt 98, 4032, Debrecen, Hungary.
J Comput Neurosci. 2009 Oct;27(2):291-308. doi: 10.1007/s10827-009-0143-9. Epub 2009 Mar 14.
When frog tadpoles hatch their swimming requires co-ordinated contractions of trunk muscles, driven by motoneurons and controlled by a Central Pattern Generator (CPG). To study this co-ordination we used a 3.5 mm long population model of the young tadpole CPG with continuous distributions of neurons and axon lengths as estimated anatomically. We found that: (1) alternating swimming-type activity fails to self-sustain unless some excitatory interneurons have ascending axons, (2) a rostro-caudal (R-C) gradient in the distribution of excitatory premotor interneurons with short axons is required to obtain the R-C gradient in excitation and resulting progression of motoneuron firing necessary for forward swimming, (3) R-C delays in motoneuron firing decrease if excitatory motoneuron to premotor interneuron synapses are present, (4) these feedback connections and the electrical synapses between motoneurons synchronise motoneuron discharges locally, (5) the above findings are independent of the detailed membrane properties of neurons.
当青蛙蝌蚪孵化时，它们的游泳需要由运动神经元驱动并由中枢模式发生器（CPG）控制的躯干肌肉协调收缩。为了研究这种协调性，我们使用了一个3.5毫米长的幼体蝌蚪CPG种群模型，其神经元和轴突长度的分布是根据解剖学估计的连续分布。我们发现：（1）除非一些兴奋性中间神经元有上升轴突，交替游泳型活动无法自我维持；（2）需要短轴突的兴奋性运动前中间神经元分布存在头尾（R-C）梯度，以获得兴奋中的R-C梯度以及向前游泳所需的运动神经元放电的相应进展；（3）如果存在兴奋性运动神经元到运动前中间神经元的突触，运动神经元放电的R-C延迟会减少；（4）这些反馈连接以及运动神经元之间的电突触会在局部使运动神经元放电同步；（5）上述发现与神经元的详细膜特性无关。
