| 講演要旨： |
Human stance and supra-postural activities require the coordination of multiple components. Because the body has many joints (≒102), muscles (≒103), and neurons (≒1014), many actions can influence posture. However, only a subset of these actions have functional utility. If postural control is to be successful (as it almost always is), then the degrees of freedom of the body must be organized or coordinated so as to promote functional control actions and avoid dysfunctional ones.
This contribution examines the dynamics of postural coordination modes involving the torso and legs in the control of stance and stance-related activities. Based on data obtained in various experiments using the same postural tracking task, we provide evidence that postural modes in humans (i) emerge out of the coalescence of multiple constraints, (ii) exhibit persistence and changes that are characteristic of self-organized systems, (iii) are modulated by the actor’s intention, (iv) are learned by modifying the intrinsic dynamics of the postural system, and (v) can be modeled with tools from classical mechanics. Similarities between postural phase transitions in humans or non-biological phenomena suggest the existence of general and common principles governing pattern formation and flexibility in complex systems, and circumscribe the generality of neurophysiologically-based theories of postural behavior. The implications of these results for the control humanoid postures (HRP2) will be presented.
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