Neuroplasticity induced by the retention period of a complex motor skill learning in rats.

Learning complex motor skills is an essential process in our daily lives. Moreover, it is an important aspect for the development of therapeutic strategies that refer to rehabilitation processes since motor skills previously acquired can be transferred to similar tasks (motor skill transfer) or recovered without further practice after longer delays (motor skill retention). Different acrobatic exercise training (AE) protocols induce plastic changes in areas involved in motor control and improvement in motor performance. However, the plastic mechanisms involved in the retention of a complex motor skill, essential for motor learning, are not well described. Thus, our objective was to analyze the brain plasticity mechanisms involved in motor skill retention in AE . Motor behavior tests, and the expression of synaptophysin (SYP), synapsin-I (SYS), and early growth response protein 1 (Egr-1) in brain areas involved in motor learning were evaluated. Young male Wistar rats were randomly divided into 3 groups: sedentary (SED), AE, and AE with retention period (AER). AE was performed three times a week for 8 weeks, with 5 rounds in the circuit. After a fifteen-day retention interval, the AER animals was again exposed to the acrobatic circuit. Our results revealed motor performance improvement in the AE and AER groups. In the elevated beam test, the AER group presented a lower time and greater distance, suggesting retention period is important for optimizing motor learning consolidation. Moreover, AE promoted significant plastic changes in the expression of proteins in important areas involved in control and motor learning, some of which were maintained in the AER group. In summary, these data contribute to the understanding of neural mechanisms involved in motor learning in an animal model, and can be useful to the construction of therapeutics strategies that optimize motor learning in a rehabilitative context.

The influence of a real job on upper limb performance in motor skill tests: which abilities are transferred?

To investigate whether the specificities of real jobs create distinctions in the performance of workers in different motor tests for the upper limbs, 24 participants were divided into two groups according to their specific job: fine and repetitive tasks and general tasks. Both groups reproduced tasks related to aiming movements, handling and strength of the upper limbs. There were no significant differences between groups in the dexterity and performance of aiming movements. However, the general tasks group had higher grip strength than the repetitive tasks group, demonstrating differences according to job specificity. The results suggest that a particular motor skill in a specific job cannot improve performance in other tasks with the same motor requirements. The transfer of the fine and gross motor skills from previous experience in a job-specific task is the basis for allocating training and guidance to workers.

Motor improvement requires an increase in presynaptic protein expression and depends on exercise type and age.

The aging process is associated with structural and functional changes in the nervous system. Considering that exercise can improve the quality of life of the elderly, the aim of this study was to evaluate the effects of exercise protocols with different motor demands on synaptic protein expression (i.e., synapsin-I and synaptophysin). Cognitive and motor brain areas and the motor performance of adult and aged animals were analyzed. Adult (7 months old) and aged (18 months old) male Wistar rats were used. Animals were divided into the following groups: treadmill exercise (TE, rhythmic motor activity), acrobatic exercise (AE, complex motor activity) and sedentary (SED, control). The animals were exposed to exercise 3 times per week for 8 weeks. The brains were collected for immunohistochemistry and immunoblotting assays. Our results showed that both types of exercise induced changes in motor performance and synaptic protein expression in adult and aged animals. However, acrobatic exercise promoted a greater number of changes, mainly in the aged animals. In addition, protein expression changes occurred in a greater number of brain areas in the aged animals than in adult animals. There were clear increases in synapsin-I expression in all areas analyzed of aged animals only after acrobatic exercises. On the other hand, synaptophysin increased in the same areas but with both types of exercise. Thus, in general, our data suggest that even at advanced ages, when the aging process is already in progress, initiating physical training may be beneficial to generate neuroplasticity that can improve motor performance.

Predictive validity analysis of six reference equations for the 6-minute walk test in healthy Brazilian men: a cross-sectional study.

BACKGROUND: The six-minute walk test (6MWT) is an important tool for evaluating functional capacity and exercise tolerance. The reference equations for the 6MWT in healthy subjects were established on the basis of American and European populations, but reference equations have been proposed with different variables for the Brazilian population. OBJECTIVE: To analyze the predictive validity of six reference equations for the six-minute walking distance (6MWD) in healthy adult men. METHODS: We evaluated 103 individuals in relation to level of physical activity (IPAQ), respiratory symptoms (MRC), handgrip strength, and 6MWD test. The data were submitted to a normality test, then the Bland-Altman agreement test was used to compare individual 6MWD values with that expected for each equation. RESULTS: The subjects were active, with a mean age of 34.12 (SD=8.88) years and no respiratory symptoms. The mean of the 6MWD was 663.43 (SD=93.01)m. The 6MWD's predicted values came closest to the walked distance covered by Britto et al.'s equation (using BMI) of 647.62 (SD=38.62)m. CONCLUSIONS: The equation proposed by Britto et al. using body mass index (BMI) was the closest to the 6MWD for the individuals studied and could be widely used as a reference tool during the 6MWT in healthy Brazilian men.

Translation, cross-cultural adaptation, and clinimetric testing of instruments used to assess patients with patellofemoral pain syndrome in the Brazilian population.

STUDY DESIGN: Clinical measurement study. OBJECTIVES: To cross-culturally adapt the Anterior Knee Pain Scale (AKPS), the Functional Index Questionnaire (FIQ), and the Pain Severity Scale (PSS) for patellofemoral pain syndrome (PFPS) into Brazilian Portuguese. This study also aimed to test the measurement properties of the AKPS, the FIQ, and the PSS, and the existing Brazilian Portuguese versions of the numeric pain rating scale (NPRS) and the Global Perceived Effect scale in a group with PFPS. BACKGROUND: PFPS is a common condition. Therefore, translated, culturally adapted, and clinimetrically tested instruments for measuring PFPS are needed. METHODS: The AKPS, FIQ, and PSS instruments were cross-culturally adapted into Brazilian Portuguese. The measurement properties of the AKPS, FIQ, PSS, NPRS, and Global Perceived Effect scale (internal consistency, ceiling and floor effects, and construct validity) were tested in 83 patients with PFPS. The reproducibility and responsiveness were tested in 52 patients with PFPS in a test-retest design, with follow-up testing at 48 to 72 hours and at 4 weeks after baseline. RESULTS: The AKPS, the FIQ, and the PSS yielded adequate internal consistency (Cronbach alpha ranging from .75 to .87) and excellent reliability (intraclass correlation coefficients [model 2,1] ranging from 0.90 to 0.97). The AKPS and the PSS yielded very good agreement (standard error of measurement, 2.9% and 3.5%, respectively). The highest correlations were observed among the AKPS, the FIQ, and the PSS (Pearson r>0.60, P<.05). No floor or ceiling effects were observed for any of the instruments. Effect sizes used for measuring internal responsiveness ranged from moderate to high for all measures. The NPRS and the AKPS were the measures with the highest external responsiveness. CONCLUSION: The Brazilian Portuguese versions of the AKPS, FIQ, PSS, NPRS, and Global Perceived Effect scale have acceptable measurement properties.

Receptores de glutamato do tipo AMPA no sistema visual de pintos: distribuiçäo e efeitos de lesöes retinianas / AMPA type glutamate receptor in visual system of young chicken: distribution and effects of retinian lesions

Diversas subunidades dos receptores de glutamato têm sido clonadas e seqüenciadas nos últimos anos, e diversos anticorpos e sondas de ácidos nucléicos agora estäo disponíveis para estudos de sua distribuiçäo e expressäo gênica, entre outros. Neste trabalho utilizamos anticorpos e sondas de RNA contra subunidades dos GluRs do tipo AMPA para estudar sua distribuiçäo no sistema visual, e verificar os possíveis efeitos de lesöes retinianas sobre a expressäo das subunidades presentes no tecto óptico de pintos. Anticorpos contra as subunidades GluR1, GluR2/3 e GluR4 foram empregados com técnicas imuno-histoquímicas para revelar sua distribuiçäo no sistema visual de pintos. As subunidades GluR1, GluR2/3 e GluR4 foram encontradas em áreas retinorrecipientes, com graus variados de co-localizaçäo. Os efeitos das lesöes retinianas sobre a expressäo das subunidades nos tectos ópticos de pintos foram investigados pelos métodos imuno-histoquímicos, ®Western blot¼ e hibridaçäo ®in situ¼. Os dois primeiros métodos revelaram uma diminuiçäo da expressäo das subunidades GluR1 e GluR2/3 nos tectos desaferentados quando comparados aos tectos controles, após 2 dias de sobrevida da lesäo, e um aumento dessas subunidades no tecto óptico desaferentado, decorridos 7 dias da lesäo. Passados 15 dias de sobrevida da lesäo retiniana, os tectos ópticos desaferentados apresentaram um aumento da expressäo da subunidade GluR1 e uma diminuiçäo das subunidades GluR2/3 quando comparado ao tecto controle. Apesar dessas mudanças observadas na expressäo dessas proteínas, os nossos achados de hibridaçäo ®in situ¼ näo revelaram mudanças na expressäo dos mRNAs das subunidades GluR1 e GluR2/3 nos tectos desaferentados. Os nossos resultados de distribuiçäo das subunidades GluR1, GluR2/3 e GluR4 parecem sugerir que diferentes populaçöes de neurônios visuais podem expressar diferentes combinaçöes de subunidades dos GluRs, podendo, portanto, os receptores de glutamato do tipo AMPA presentes nessas regiöes terem propriedades particulares em funçäo do tipo de subunidade que compöe os complexos receptores. Os efeitos observados das lesöes retinianas parecem indicar que essas lesöes podem induzir uma ®down-regulation¼ das subunidades GluR1 e GluR2/3 após curtos períodos de sobrevida e uma ®up-regulation¼ dessas mesmas subunidades após 7 dias de sobrevida da lesäo. Estes efeitos provavelmente se devem à remoçäo das aferências glutamatérgicas originadas nas células ganglionares da retina