Background:Falling and fear of falling are among the most common problems of the elderly, which can cause illness, isolation, dependency and reduced quality of life in elderly. Exercise is recommended to prevent falling injuries in the elderly.Aim:This study aimed to examine the effect of Tai Chi exercise on the risk and fear of falling in older adults.Materials and Methods:In this randomized clinical trial, a total of 60 male and female elderly were randomly divided into two groups: Tai Chi exercise and control (daily activities) groups. Tai Chi exercise protocol in the intervention group consisted of 3 sessions per week for 10 weeks. The risk and fear of falling were assessed in subjects by using standardized questionnaires, including Berg’s Balance Scale and Fall Efficacy Scale-International (FES-I) before initiating the protocol, at the end of 4th, 8th weeks and at the end of exercise period.Results:Two groups were matched in terms of age, gender, education, and body mass index. Baseline values of risk of falling and fear of falling were not significantly different between the two groups (P>0.05). The score of fear of falling at the end of 4th, 8th weeks and at the end of exercise period was significantly different between the two groups (P<0.05) and it decreased in the intervention group, but the risk of falling reduced after 8 and 10 weeks in the intervention group (P<0.001).Conclusion:Performing Tai Chi exercises for at least four weeks could reduce fear of falling and reduce the risk of falls in older adults after 8 weeks.
During navigation, information at multiple scales needs to be integrated. Single-unit recordings in rodents suggest that gradients of temporal dynamics in the hippocampus and entorhinal cortex support this integration. In humans, gradients of representation are observed, such that granularity of information represented increases along the long axis of the hippocampus. The neural underpinnings of this gradient in humans, however, are still unknown. Current research is limited by coarse fMRI analysis techniques that obscure the activity of individual voxels, preventing investigation of how moment-to-moment changes in brain signal are organized and how they are related to behavior. Here, we measured the signal stability of single voxels over time to uncover previously unappreciated gradients of temporal dynamics in the hippocampus and entorhinal cortex. Using our novel, single voxel autocorrelation technique, we show a medial-lateral hippocampal gradient, as well as a continuous autocorrelation gradient along the anterolateral-posteromedial entorhinal extent. Importantly, we show that autocorrelation in the anterior-medial hippocampus was modulated by navigational difficulty, providing the first evidence that changes in signal stability in single voxels are relevant for behavior. This work opens the door for future research on how temporal gradients within these structures support the integration of information for goal-directed behavior.
Transcranial magnetic stimulation (TMS) delivered to the angular gyrus (AG) affects hippocampal function and associated behaviors (Thakral PP, Madore KP, Kalinowski SE, Schacter DL. Modulation of hippocampal brain networks produces changes in episodic simulation and divergent thinking. 2020a. Proc Natl Acad Sci U S A. 117:12729–12740). Here, we examine if functional magnetic resonance imaging (fMRI)-guided TMS disrupts the gradient organization of temporal signal properties, known as the temporal organization, in the hippocampus (HPC) and entorhinal cortex (ERC). For each of 2 TMS sessions, TMS was applied to either a control site (vertex) or to a left AG target region (N = 18; 14 females). Behavioral measures were then administered, and resting-state scans were acquired. Temporal dynamics were measured by tracking change in the fMRI signal (i) “within” single voxels over time, termed single-voxel autocorrelation and (ii) “between” different voxels over time, termed intervoxel similarity. TMS reduced AG connectivity with the hippocampal target and induced more rapid shifting of activity in single voxels between successive time points, lowering the single-voxel autocorrelation, within the left anteromedial HPC and posteromedial ERC. Intervoxel similarity was only marginally affected by TMS. Our findings suggest that hippocampal-targeted TMS disrupts the functional properties of the target site along the anterior/posterior axis. Further studies should examine the consequences of altering the temporal dynamics of these medial temporal areas to the successful processing of episodic information under task demand.
The aim of the current study is to compare the effects of hypertrophy-, strength-, and power-type resistance exercise training types on hydrogen peroxide (H 2 O 2), malondialdehyde (MDA), total lactate dehydrogenase (LDH), and total creatine kinase (CK) in resistance-trained women. Methods After determining one-repetition maximum (1-RM), ten resistance-trained women (age 26.30 ± 4.95 years; body mass index 22.07 ± 2.02 kg/m 2 ; body fat 24.64 ± 4.98%) conducted hypertrophy-type (70% of 1-RM), strength-type (90% of 1-RM), and power-type (45% of 1-RM) resistance exercise for three consecutive weeks. The movements included lever leg extension, reverse-grip lat pull-down, horizontal leg press, standing biceps cable curl, lying leg curl, machine bench press, standing cable triceps extension, and seated calf raises. Fasting blood samples were obtained immediately before and immediately after each trial. Statistical analyses were performed using the t test, Wilcoxon, and analysis of covariance. The significance level was set at P < 0.05 level. Results The results indicated that one bout of hypertrophy-, strength-, and power-type resistance exercises had no significant effects on H 2 O 2 , MDA, and total LDH levels. However, serum total CK level significantly increased after all the three types of resistance exercise. Power resistance exercise resulted in a higher total CK level than hypertrophy and strength types. Conclusion Although the three types of hypertrophy, strength, and power exercise cause muscle damage, they do not exacerbate oxidative stress in resistance-trained women.
During navigation, information at multiple scales needs to be integrated. Single-unit recordings in rodents suggest that gradients of temporal dynamics in the hippocampus and entorhinal cortex support this integration. In humans, gradients of representation are observed, such that granularity of information represented increases along the long axis of the hippocampus. The neural underpinnings of this gradient in humans, however, are still unknown. Current research is limited by coarse fMRI analysis techniques that obscure the activity of individual voxels, preventing investigation of how moment-to-moment changes in brain signal are organized and how they are related to behavior. Here, we measured the signal stability of single voxels over time to uncover previously unappreciated gradients of temporal dynamics in the hippocampus and entorhinal cortex. Using our novel, single voxel autocorrelation technique, we show for the first time a medial-lateral hippocampal gradient, as well as a continuous autocorrelation gradient along the anterolateral-posteromedial entorhinal extent. Importantly, we show that anterior-posterior and medial-lateral hippocampal autocorrelation gradients were modulated by navigational difficulty, indicating that changes in signal stability are relevant for behavior. Our method and findings open the door for future research on how temporal gradients within these structures support the integration of information for goal-directed behavior.
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