AN INFORMATION-FLOW MODEL OF THE ORGANIZATION OF MOTOR ACTIVITY. II. SAMPLING, CENTRAL PROCESSING, AND UTILIZATION OF SENSORY INFORMATION

Perception of Movement Patterns. Recognition from Visual Arrays of Distorted Patterns

A review of literature indicates that the perception and memory of movement patterns with kinaesthesis might be expected to differ depending on whether a movement pattern is actively commanded or passively induced. In addition, it has been suggested that kinaesthesis is a gross sense in the absence of vision. An attempt was made to demonstrate differences between the perception and memory of actively commanded movement patterns, passively induced movement patterns, and visual patterns formed by a moving light. A visual recognition test was employed. While it was apparent that the recognition task was a sensitive one for testing the accuracy of pattern perception, no significant difference was demonstrated between the three movement conditions.

Bilateral transfer in tapping skill in the absence of peripheral information

Bilateral transfer in a fast tapping task was investigated under normal (+FB) and reduced (-FB) feedback conditions, in the -FB experiment 36 Ss were assigned to 3 groups: preferred (PH) to non-preferred (NPH) shift; NPH to PH; and alternating trials of PH and NPH. With + FB 2 further groups of 12 Ss transferred PH to NPH or NPH to PH. 8 preshift and 8 postshift trials were given. The alternating group had 8 PH and 8 NPH trials. In preshift performance increment was found in ail groups except in +FB with NPH. With +FB some facilitation in transfer was obtained for the NPH; under -FB marked positive transfer was found for the PH. Alternating PH and NPH performance conformed to preshift levels. Results were discussed in terms of differential central control processes for the two hands.

A closed-loop theory of motor learning

Following a discussion of the meaning of the term "skills" and a review of historical influences on their learning, a closed-loop theory for learning simple movements is presented. Empirical generalizations from the literature are stated, and the theory is used to explain them. The generalizations are of 2 classes: learning through the application of knowledge of results, and the effects of withdrawing knowledge of results.

A dynamic model for simulating a trip and fall during gait

The purpose of this study was to develop an analytical model to simulate a trip and fall during gait. The human body was modeled as a 12 degree-of-freedom linkage system. The kinematics of the lower extremity for one cycle of gait were obtained for a healthy subject using an optoelectronic three-dimensional data acquisition system. Inverse dynamics was used to compute the moments about the hip, knee and ankle joints of the lower extremity. These moments were then used as input actuators to the joints in to a forward dynamics model to simulate the swing phase of gait from toe-off to heel-strike. An optimization procedure to minimize errors associated with the computed experimental torque was applied to correct for mathematical instability. An experiment was performed to measure the three-dimensional foot--obstacle contact force for a healthy subject tripping on an obstacle during gait. The contact force was applied to the swing limb of the forward dynamics model for 0.09 s beginning at 0.04 s after toe-off. Tripping on an obstacle followed by a muscle-relaxed fall was simulated. The simulation results were visualized with animation software.