Early motor development from partially ordered neural-body dynamics: experiments with a cortico-spinal-musculo-skeletal model

Abstract

Early human motor development has the nature of spontaneous exploration and boot-strap learning, leading to open-ended acquisition of versatile flexible motor skills. Since dexterous motor skills often exploit body-environment dynamics, we formulate the developmental principle as the spontaneous exploration of consistent dynamical patterns of the neural-body-environment system. We propose that partially ordered dynamical patterns emergent from chaotic oscillators coupled through embodiment serve as the core driving mechanism of such exploration. A model of neuro-musculo-skeletal system is constructed capturing essential features of biological systems. It consists of a skeleton, muscles, spindles, tendon organs, spinal circuits, medullar circuits (CPGs), and a basic cortical model. Through a series of experiments with a minimally simple body model, it is shown that the model has the capability of generating partially ordered behavior, a mixture of chaotic exploration and ordered entrained patterns. Models of self-organizing cortical areas for primary somatosensory and motor areas are introduced. They participate in the explorative learning by simultaneously learning and controlling the movement patterns. A scaled up version of the model, a human infant model, is constructed and put through preliminary experiments. Some meaningful motor behavior emerged including rolling over and crawling-like motion. The results show the possibility that a rich variety of meaningful behavior can be discovered and acquired by the neural-body dynamics without pre-defined coordinated control circuits.

Creating and modulating rhythms by controlling the physics of the body

“…Conversely, those corresponding to the latter case create entrainment by exploiting the body dynamics; e.g., the morphological computation by Pfeifer and colleagues cf. also, Williamson 1998;Berthouze 2002, 2004;Iida and Pfeifer 2004;Der et al 2006;Kuniyoshi and Suzuki 2004;Kuniyoshi and Sangawa 2006).…”

Body Schema in Robotics: A Review

“…The latter category comprises studies in which the acquired body representations are utilized to coordinate the robot's behavior [138]- [140]. Third, we will review the work by Kuniyoshi and Sangawa [141] where the emphasis is placed on the physical interaction between body and environment and on the effect of low-level (spinal) control. On top of these, low-level sensorimotor representations can emerge.…”

“…Kuniyoshi and Sangawa [141] investigated the role of tight coupling between a body and its environment and how consistent dynamical patterns can emerge from this close physical interaction. They proposed a model of a neuro-musculo-skeletal system that consists of biologically realistic components such as a skeleton, muscles, spindles, tendon organs, spinal circuits, medullar circuits, and central pattern generators (CPGs).…”

Darwinian Dynamics of Embodied Chaotic Exploration

“…Kuniyoshi and Sangawa [7] made the important suggestion that chaotic dynamics underpin crucial periods in animal development when brain-body-environment dynamics are explored in a spontaneous way as part of the process of acquiring motor skills. A few robotics studies have demonstrated that chaotic neural networks can indeed power the self-exploration of brain-body-environment dynamics in an embodied system, discovering self organized patterns that can be incorporated into motor behaviors [8,6,12].…”