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In order to better understand the role of the vestibular system in postural adjustments on unstable surfaces, we analyzed the effects of galvanic vestibular stimulation (GVS) on the pattern of muscle activity and joint displacements (ankle knee and hip) of eight intellectually normal participants (control group--CG) and eight control group individuals with Down syndrome (DS) while balancing on seesaws of different heights. The CG individuals adopted a pattern of muscle activation characterized by alternation between ankle agonist and antagonist muscles. The individuals with DS adopted a pattern of muscle co-contraction. The GVS affected neither the ability of CG individuals to maintain balance nor their pattern of muscle contraction. On the other hand, the individuals with DS showed greater sensitivity to GVS while balancing on a seesaw and were not able to select the appropriate motor strategy to efficiently balance and compensate the effects of GVS. These increased vestibular sensitivities observed in individuals with DS can reflect deficits in the proprioceptive system. (Contains 3 figures and 2 tables.)

Background: The purpose of this study was to investigate the kinematic and electromyography strategy used by individuals with intellectual disability to keep equilibrium during anterior-posterior balance on seesaws with different degrees of instability. Method: Six individuals with Down syndrome (DS) and six control group individuals (CG) balanced on three seesaws. The movement of the hip, knee and ankle joints and electromyography activities of selected leg and trunk muscles were recorded. Results: Both groups maintained their balance mainly at the ankle joint. Contrary to the CG, the individuals with DS adopted a pattern of co-contraction and were not able to modulate the magnitude of postural response with the seesaw's degree of instability. Conclusions: These unusual strategies used by individuals with DS, such as their inability to discriminate different levels of mechanical demands in terms of the seesaw's instability, can reflect deficits in the proprioceptive system. The integration at cerebellum level could be a good candidate.

Climatic conditions that are thermally inappropriate for dairy cattle are associated with a reduction in feed consumption, production, and the composition of the final product. The objective of this research was to identify the influence of the evaporative adiabatic cooling system (EACS) on the thermal comfort and productive responses of dairy cattle, through multivariate analysis by principal components, in the summer and winter seasons of the semiarid region of Pernambuco, Brazil. The data came from an experiment that included 16 multiparous lactating cows, randomly distributed in 4 sets, with 4 experimental phases and 4 treatments (0, 10, 20, and 30 min of exposure to EACS). Multivariate analysis was used utilizing principal components for the thermal comfort indexes, physiological variables, milk production, and composition. The highest milk production in the summer season was for animals exposed to the cooling system for 30 min. In the winter season in the morning shift, the use of the evaporative cooling system for 10 min was sufficient for improvements in milk production. The times of exposure to EACS caused changes in the composition of milk, both in summer and in winter. Thermal stress was characterized by a high temperature and humidity index in all treatments in the afternoon shift. The principal component analysis allowed us to identify the positive influence of evaporative cooling on thermal comfort, physiological responses, production, and composition milk of lactating cows. [ABSTRACT FROM AUTHOR]