Rosenblum L D, Turvey M T
Center for the Ecological Study of Perception and Action, University of Connecticut, Storrs 06268.
Neuroscience. 1988 Oct;27(1):289-300. doi: 10.1016/0306-4522(88)90238-2.
Evidence from the oscillatory behavior of fish fins and the crayfish swimmeret system suggests that local rhythmic-pattern generators preserve their characteristic properties over the various locomotory co-ordinations in which they participate. This maintenance tendency, as von Holst termed it, was investigated in an experiment in which human subjects swung, through motions at the wrists, hand-held pendulums of variable mass and length. In the experiment (comprising six sessions over 21 months with the same three subjects) the context for the maintenance tendency was steady-state absolute co-ordination: two rhythmic units oscillating at a single, common period and at a bounded phase relation. The experimental methodology permitted systematic control of (a) the characteristic periods of the individual rhythmic units and (b) the deviations from these periods. Relative fluctuations in periodic timing and amplitude were least when a rhythmic unit's period in absolute co-ordination approximated its characteristic period and increased with departures from the characteristic period. Rates of increase in timing fluctuations were approximately the same for deviations on either side of the characteristic period; the rate of increase in spacing fluctuations was substantially greater for the range in which periods were less than the characteristic period. The phase relation between two co-ordinated rhythmic movement units in absolute co-ordination depended on the difference between their characteristic periods. The intended phase relation of 180 degrees was attained only when the characteristic periods were identical. When the characteristic periods differed, the departure from 180 degrees increased systematically with the difference. The fluctuation results are discussed in terms of the relation between relaxation and harmonic dynamics in producing rhythmic movements, with particular emphasis on the harmonic tuning of relaxation oscillations. The phase results are discussed in terms of whether or not the very many stable phase relations in absolute co-ordination are reflective of the nervous system or of differences in response latencies in left and right muscle systems induced by different degrees of inertial compensation.
来自鱼鳍的摆动行为和小龙虾游泳足系统的证据表明，局部节律模式发生器在它们参与的各种运动协调过程中保持其特征属性。正如冯·霍尔斯特所描述的，这种保持趋势在一项实验中得到了研究，在该实验中，人类受试者通过手腕的运动摆动不同质量和长度的手持摆锤。在该实验中（由相同的三名受试者在21个月内进行了六个阶段的实验），保持趋势的背景是稳态绝对协调：两个节律单元以单一的共同周期和有界的相位关系振荡。实验方法允许系统地控制：（a）各个节律单元的特征周期；（b）与这些周期的偏差。当一个节律单元在绝对协调中的周期接近其特征周期时，周期定时和振幅的相对波动最小，并随着与特征周期的偏离而增加。对于特征周期两侧的偏差，定时波动的增加速率大致相同；对于周期小于特征周期的范围，间距波动的增加速率要大得多。绝对协调中两个协调的节律运动单元之间的相位关系取决于它们的特征周期之间的差异。只有当特征周期相同时，才会达到预期的180度相位关系。当特征周期不同时，与180度的偏差会随着差异而系统地增加。根据产生节律运动时松弛与谐波动力学之间的关系来讨论波动结果，特别强调松弛振荡的谐波调谐。根据绝对协调中众多稳定的相位关系是否反映神经系统或不同程度的惯性补偿引起的左右肌肉系统反应潜伏期差异来讨论相位结果。
