REFLEX CONDUCTION IN THE GIANT FIBRES OF THE EARTHWORM
REFLEX CONDUCTION IN THE GIANT FIBRES OF THE EARTHWORM
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DOI：
10.1098/rspb.1946.0005
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发表时间：
1946-01-01
期刊：
影响因子：
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通讯作者：
RUSHTON, WAH
中科院分区：
文献类型：
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作者：
RUSHTON, WAH
目前的工作证实了Friedländer和其他人的结论，即巨纤维介导了纤维中端到端的缩短反应。主要关注的是调查斯托夫的主张，即中间的巨人纤维进行冲动，只有在方向从头部到尾部和横向巨人只有在相反的方向。采用了两种方法。(a)在蠕虫的每一端暴露神经索，当蠕虫的表面在不同的地方被触摸时，从两个末端同时采集电记录。结果通常是在一根或另一根巨大的纤维中出现一系列脉冲，并且发现，每当脉冲出现在给定纤维的一端时，它总是出现在同一纤维的另一端。因此，每根纤维在传导时，总是在两个方向上传导。头部的感觉神经似乎只与正中巨肌相连，因为刺激阴蒂前不会引起侧纤维活动。同样，尾巴似乎只与横向的巨纤维相连。(b)斯托夫自己的方法被使用，他的观察证实，扩展和重新解释。无论是中间或两侧纤维分为一段。手术的成功与否可以通过未解剖的蠕虫的巨纤维反应来判断（图5）。第二天，当蠕虫恢复时，当触摸蠕虫的头部、尾部或中部时，观察到缩短反射。缩短或贯穿整个过程，或在手术部位停止，这取决于活性巨纤维是完整的还是受损的。结果总结在第119页。从头部和尾部都证实了斯托夫的观察，并且同意头部的脉冲仅由中间巨星传导回来。脑干中没有冲动，可能是由于斯托夫假设的相反的单向传导，或者是由于它们与头部的感觉联系的缺乏。但是，上面（a）表明后者是正确的，而且从接触蠕虫的中间区域也必须得出同样的结论，显然斯托夫没有这样做，因为这部分与侧巨人相连，从而证明这些纤维也可以前后传导。因此，不同巨纤维的功能差异可能与它们在感觉分布上的差异有关。
The present work confirms the conclusion of Friedländer and others that the giant fibres mediate the end-to-end shortening reaction in the earthworm. The chief concern has been to investigate Stough’s claim that the median giant fibre conducts impulses only in the direction from head to tail and the lateral giants only in the reverse direction. Two methods have been employed. (a) The nerve cord was exposed at each end of the worm, and electrical records taken simultaneously from the two extremities when the surface of the worm was touched at different places. The results were usually a train of impulses in one or other giant fibre, and it was found that whenever an impulse appeared at one end of a given fibre, it always appeared at the other end of the same fibre. Each fibre, therefore, when it conducted at all, always conducted in both directions. Sensory nerves from the head appeared only connected to the median giant, since stimulation anterior to the clitellum never resulted in lateral fibre activity. Similarly, the tail appeared only to join with the lateral giant fibres. (b) Stough’s own method was used, and his observations confirmed, extended and re-interpreted. Either the median or both lateral fibres were divided in one segment. The success of this operation could be judged by leading off the giant fibre responses from the undissected worm (figure 5). Next day, when the worm had recovered, the shortening reflex was observed when the worm was touched at the head, the tail, or in the middle. The shortening was either throughout, or was arrested at the operation site, depending upon whether the active giant fibre was the intact or the damaged one. The results are summarized on p. 119. From both the head and the tail Stough’s observations are confirmed, and it is agreed that impulses from the head are conducted back by the median giant alone. The absence of impulses in the laterals might be due to contrary one-way conduction as Stough assumes, or to the absence of their sensory connexion with the head. But (a) above shows that the latter is correct, and the same must be concluded from touching the middle region of the worm, which apparently Stough did not do, for this part connects with the lateral giants, and thus affords a demonstration that these fibres may also conduct antero-posteriorly. The difference in function of the separate giant fibres, therefore, is probably related to their difference in sensory distribution.