Characteristics of the postural reactions of the dog to a controlled disturbance

Abstract

Dogs were trained to stand quietly on a movable platform during exposure to virtual step functions of horizontal headward displacement of the surface. Reactions were detected as vertical force changes exerted by the posterior feet and as changes in EMG [electromyogram] activity of muscles of the thigh. The patterns of force change were uniform and predictable across trials and across dogs. Four similarly constant patterns of muscle reaction have been detected among the various muscles tested. These patterns suggest the occurrence of critical delays in the postural control system around 20-25 msec, 50-55 msec, and 80-90 msec. The predictable nature of the reaction implies the existence in the central nervous system of a uniform pattern of neural changes which underlies the external manifestations of response.