Activation patterns of embryonic chick hind limb muscles recorded in ovo and in an isolated spinal cord preparation.
Activation patterns of embryonic chick hind limb muscles recorded in ovo and in an isolated spinal cord preparation.
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在卵和分离的脊髓制剂中记录的胚胎鸡后肢肌肉的激活模式。
DOI：
10.1113/jphysiol.1984.sp015061
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Michael J. O'Donovan
中科院分区：
文献类型：
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作者：
L. Landmesser;Michael J. O'Donovan
用肌电（e.m.g.）在34 - 36期胚胎的分离脊髓/后肢制备物中记录，并与卵内e.m.g.相似阶段胚胎的活动。卵内的肌肉活动由周期性重复的爆发序列组成，在此期间，拮抗肌通常交替出现，协同肌共同活动，与其成熟功能一致。然而，也观察到更多的可变行为。卵内爆发序列通常由短持续时间、高振幅放电启动，该放电在所有研究的肌肉中同步发生，随后是屈肌中最长的电沉默期。这种类型的活动以前没有在成熟动物中描述过。在卵运动序列一般发起伸肌活动，在整个序列的持续时间和强度逐步下降，而屈肌活动逐步加强。伸肌活动的开始伴随着屈肌活动的突然减少，而相反的情况没有观察到。当脊髓和后肢被分离并保持在氧合台氏液中数小时时，也发生自发运动序列。传入神经阻滞实验表明，在这个准备运动模式集中产生的脊髓内的电路。活动从孤立的索是较少的变量比发生在卵，由序列的高度定期复发的爆发。每次爆发都以短暂的高振幅放电开始，该放电在所有肌肉中同步发生，并且与在卵中观察到的相似。随后是一个安静的时期，这是最长的屈肌，然后是一个更长的爆发。虽然它的行为在某些方面不同于在卵，它的结论是，在体外保持孤立的脊髓产生自发的和模式化的运动输出。
Muscle activation patterns of embryonic chick hind limb muscles were determined from electromyographic (e.m.g.) recordings in an isolated spinal cord/hind limb preparation of stage 34‐36 embryos, and were compared with in ovo e.m.g. activity from similarly staged embryos. Muscle activity in ovo consisted of periodically recurring sequences of bursts during which antagonistic muscles often alternated and synergistic muscles were co‐active, as compatible with their mature function. However, more variable behaviour was also observed. Burst sequences in ovo were often initiated by a short‐duration, high‐amplitude discharge that occurred synchronously in all muscles studied, and which was followed by a period of electrical silence that was longest in the flexor muscles. This type of activity has not been described previously in mature animals. In ovo movement sequences were generally initiated by extensor activity which progressively declined in duration and intensity throughout the sequence, while flexor activity progressively intensified. The onset of activity in extensor muscles was accompanied by an abrupt decrease in flexor activity, whereas the converse was not observed. Spontaneous movement sequences also occurred when the spinal cord and hind limb were isolated and maintained in oxygenated Tyrode solution for several hours. Deafferentation experiments indicated that the motor pattern in this preparation was generated centrally by circuits within the spinal cord. Activity from the isolated cord was less variable than that occurring in ovo, consisting of sequences of highly regular recurring bursts. Each burst began with a brief high‐amplitude discharge that occurred synchronously in all muscles and which was similar to that observed in ovo. This was followed by a silent period, which was longest in the flexors, and then by a more prolonged burst. Although its behaviour differs from that in ovo in some respects, it is concluded that the isolated cord maintained in vitro produces a spontaneous and patterned motor output.