A research group at Osaka University has found a candidate for a reflex circuit that produces stable walking movements in cats by developing a quadruped robot that can reproduce the characteristics of animal nerves and muscles.
Experimental studies in the latter half of the 20th century aimed at elucidating the mechanism by which quadrupeds walk efficiently and stably have revealed several neural mechanisms, but now animals that move around alive from the viewpoint of animal welfare. It is difficult to investigate the mechanism from the inside.The structure of how the discovered neural mechanisms are integrated in the animal's body, that is, how the reflex circuits that control gait are wired, has not yet been clarified.
Therefore, this time, the group has developed a four-legged robot that reproduces the characteristics of animal nerves and muscles on a computer and walks instead of examining actual animals.By conducting a walking experiment using this robot, we searched for a reflex circuit that produces walking. We discovered a "mutual excitability circuit between the hip and knee extensors" with an extremely simple structure of "extending the knee joint."By simply reproducing this reflection circuit on each foot, the robot produced stable walking, and conversely, when the circuit was cut, walking became unstable.
In addition, when this circuit is stimulated, a support leg extension phenomenon similar to that of cats (a phenomenon in which the legs remain on the ground and the next step cannot be taken) appears, so this circuit is important to control the walking of cats. It was suggested that it was a good circuit.
In this way, by using robots that replace experimental animals, more researchers will be able to investigate the mechanism of animals under a wide range of experimental conditions, elucidate the mechanism by which animals walk skillfully, and of animals. It is expected that new findings will be brought toward the development of robots that move around efficiently and flexibly.
