Kato Chihiro, Mihashi Koshin, Ishida Sachiko
Graduate School of Mathematics, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
Behav Brain Res. 2004 Apr 2;150(1-2):9-14. doi: 10.1016/j.bbr.2003.06.001.
Planarians are phylogenetically considered to be the most primitive animals to have acquired a central nervous system and a bilateral symmetry. However, very little is known about the relationship between planarian brain integration and motility. A behavioural and histological study was therefore undertaken in an aspect of planarian motility recovery during its process of regeneration. Quantitative analysis showed that the tail-regenerates recovered their motility gradually as the new heads reformed, while the non-head reforming tail fragments showed no signs of recovery. The head fragments recovered their motility soon after cutting. The cephalic margin was not a function of the motility. The brain regenerated back to its original form in approximately two weeks, the same amount of time it took for the decapitated tails to recover their motility to initial levels. This study provides quantitative evidence that the planarian motility recovered in relation to the head formation during its process of regeneration. Our results reinforce the view that the brain plays a functional part in activating planarian motility.
从系统发育角度来看，涡虫被认为是最早获得中枢神经系统和两侧对称的最原始动物。然而，关于涡虫大脑整合与运动性之间的关系，我们所知甚少。因此，我们针对涡虫再生过程中的运动性恢复进行了一项行为学和组织学研究。定量分析表明，随着新头部的形成，尾部再生体逐渐恢复其运动性，而未形成头部的尾部片段则没有恢复的迹象。头部片段在切割后很快恢复了运动性。头部边缘并非运动性的一个功能因素。大脑在大约两周内再生恢复到其原始形态，这与断头尾部恢复到初始运动水平所需的时间相同。这项研究提供了定量证据，表明涡虫在再生过程中，其运动性的恢复与头部形成有关。我们的结果强化了这样一种观点，即大脑在激活涡虫运动性方面发挥着功能性作用。
