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We constructed a recurrent neural network model that can generate human reaching motion. Given a target position, the neural network model is capable of producing muscular activation signals that move the hand to the target endpoint, while solving the problem of musculoskeletal redundancy by dynamic relaxation of the energy functions embedded in the network. The proposed neural network model was integrated with a two-dimensional three-link eight muscle musculoskeletal model of the human arm to simulate arm reaching movements in the horizontal and sagittal planes. Our results demonstrate that the model is capable of generating natural arm movements that have spatiotemporal features, such as a slightly curved hand path and the characteristic bell-shaped velocity profile, that are similar to those of actual human movements. Some aspects of the proposed computational framework might be utilized in the central nervous system for generation of reaching movements. [ABSTRACT FROM AUTHOR]

To determine the effects of indigestible sugars on the digestibilities of nutrients and utilization of nitrogen (N) in adult male rabbits, 12 rabbits with or without a collar that prevented cecotrophy were fed experimental diets for 8 days, comprising 3 days for adaptation and 5 days for collection of feces and urine. The experimental diets were formulated by adding D-mannitol or citrus pectin to a commercial diet at 60 g/kg. In the rabbits allowed cecotrophy, mannitol increased the absorption of crude ash but did not significantly alter the digestibilities of crude protein (CP), dry matter and acid-detergent fiber. By contrast, the digestibility of CP was decreased by pectin. The ratios of retained N to consumed N and absorbed N were elevated by mannitol. In the rabbits prevented from cecotrophy, mannitol had no effect on N retention, but increased the N content of cecotrophs (soft feces) and the ratio of the N content of cecotrophs to consumed N. Pectin did not have any significant influences on N retention and the N content of cecotrophs. These results suggest that D-mannitol stimulates cecal microbial proliferation, thereby improving N utilization in rabbits. [ABSTRACT FROM AUTHOR]