Functionally heterogeneous segmental oscillators generate swimming in the medicinal leech
Functionally heterogeneous segmental oscillators generate swimming in the medicinal leech
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DOI：
10.1007/s003590000140
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发表时间：
2000-09-01
期刊：
影响因子：
--
通讯作者：
Friesen, WO
中科院分区：
文献类型：
--
作者：
Hocker, CG;Yu, XT;Friesen, WO
内侧水貂的游泳行为是由腹神经索内的神经元回路引起的。尽管腹神经索由一系列同源节段性神经节组成，但单个神经节内的游泳振荡器回路是否在功能上相等仍未得到解决。我们扩展了以前对神经节的研究，以测试神经索上的单个神经节是否能够产生游泳振荡，并测量局部振荡的周期。我们发现，单个神经节的游泳生成函数是广泛分布的，但不是均匀的。来自前节神经索的孤立神经节的游泳式振荡不如来自脊髓中的神经节的强烈。脊髓后神经节的游泳活动更弱--我们无法从12节段后的单个神经节获得类似游泳的摆动。游泳周期呈U型函数：最前面的单个神经节(M2神经节为2.3万)和后节短链(高达4.0S)的游泳周期比脊髓中神经节的长2~4倍(接近1.0 S)。我们得出结论，水蚤游泳系统由一组功能不同的本机振荡器单元组成。
Swimming behavior in the leach Hirudo medieinalis arises from neuronal circuits within the ventral nerve cord. Although the ventral nerve cord comprises a series of homologous segmental ganglia, it remains unresolved whether the swim oscillator circuits within individual ganglia are functionally equivalent. We have extended previous studies on pairs of ganglia to test whether individual ganglia throughout the nerve cord are capable of generating swim oscillations and to measure the cycle periods of local oscillations. We found that the swim-generating function of individual ganglia is broadly distributed, but not uniform. The swim-like oscillations in isolated ganglia from the anterior ganglia nerve cord were less robust than those from mid-cord. Swimming activity in posterior cord ganglia is even weaker - we were unable to obtain swim-like oscillations from individual ganglia of the nerve cord posterior to segment 12. Swim-cycle periods exhibited a U-shaped function: those recorded in the most anterior individual ganglia (2.3 s for ganglion M2) and short chains of posterior ganglia (up to 4.0 s) were two to four times longer than those obtained from mid-cord ganglia (near 1.0 s). We conclude that the leech swim system comprises a functionally heterogeneous set of local oscillator units.