Thiamine tetrahydrofurfuryl disulfide promotes voluntary activity through dopaminergic activation in the medial prefrontal cortex

A physically active lifestyle is associated with better health in body and mind, and it is urgent that supporting agents for such lifestyles be developed. In rodents, voluntary locomotor activity as an active physical behavior may be mediated by dopaminergic neurons (DNs). Thiamine phosphate esters can stimulate DNs, and we thus hypothesized that thiamine tetrahydrofurfuryl disulfide (TTFD), a thiamine derivative, promotes locomotor activity via DNs in rats. Acute i.p. administration of TTFD enhanced rat locomotor activity in a normal cage. In vivo microdialysis revealed that TTFD-enhanced locomotor activity was synchronized with dopamine release in the medial prefrontal cortex (mPFC). Antagonism of the dopamine D1 receptor, but not D2 receptor, in the mPFC fully suppressed TTFD-enhanced locomotor activity. Finally, we found a TTFD dose-dependent increase in voluntary wheel running. Our findings demonstrate that DNs in the mPFC mediates TTFD-enhanced locomotor activity, suggesting the potential of TTFD to induce active physical behavior

Application of a NIRS Neuroimaging Method to Elucidate Neural Mechanisms of Exercise-cognition Interaction

PURPOSE There is growing attention on a neuroimaging method called near-infrared spectroscopy (NIRS), which enables the monitoring of task-related regional hemodynamic responses in the brain. The basic principles and appropriate experimental conditions should be explained to eliminate potent contaminations caused by exercise itself and to summarize well-organized recent studies focusing on the interaction between exercise and cognition before applying this noninvasive neuroimaging method to various studies in the field of Exercise Science. METHODS A comprehensive search of PubMed, Web of Science, and Google Scholar was performed to obtain recent studies examining the effects of exercise (or physical activity) on the executive functions localized in the prefrontal cortex by adopting the NIRS system. RESULTS NIRS system enables exercise scientists to measure regional brain activity to investigate the effects of exercise on cognition and its neural substrates. Numerous studies have revealed that higher physical activity (or fitness) levels are related to better performance with increased prefrontal cortical activation during a task. Moreover, several longitudinal exercise intervention studies have demonstrated improved executive performance without increased task-related brain activation, particularly among older adults. CONCLUSIONS NIRS neuroimaging studies support the notion that exercise has beneficial effects on executive function, with exercise-elicited functional changes in the prefrontal cortex

Aerobic fitness associates with mnemonic discrimination as a mediator of physical activity effects: evidence for memory flexibility in young adults

A physically active lifestyle has beneficial effects on hippocampal memory function. A potential mechanism for this effect is exercise-enhanced hippocampal plasticity, particularly in the dentate gyrus (DG). Within hippocampal memory formation, the DG plays a crucial role in pattern separation, which is the ability to discriminate among similar experiences. Computational models propose a theoretical hypothesis that enhanced DG-mediated pattern separation leads to “memory flexibility”–a selective improvement in the ability to overcome moderate levels of mnemonic interference. Thus, in the current cross-sectional study of healthy young adults, we tested the working hypothesis that aerobic fitness, as a physiological indicator of endurance capacity associated with physical activity, is strongly associated with mnemonic discrimination at moderate interference levels. When divided the sample (n = 75) based on a median split of aerobic fitness, the higher fitness group had better discrimination performance for moderate interference levels compared to the lower fitness group, namely, exhibited memory flexibility. Moreover, aerobic fitness levels were positively associated with discrimination performance for moderate interference levels, as a mediator of physical activity effects. This evidence suggests that aerobic fitness levels are associated with hippocampal DG-related memory, which is consistent with literature showing positive effect of physical exercise on hippocampal memory

Control of a Prosthetic Arm Using fNIRS, a Neural-Machine Interface

Development in the field of bio-mechatronics has provided diverse ways to mimic and improve the function of human limbs. Without an elbow joint, the hand remains stiff because all the muscles tension passes through this joint. Advanced myoelectric prosthetic devices are limited due to the lack of appropriate signal sources on residual amputee muscles and insufficient real-time control. Neural-machine interfaces (NMI) are representing a recent approach to develop effective applications. In this research study, an NMI is designed that presents real-time signal processing for command generation. The human brain hemodynamic responses are, therefore, translated into control commands for people suffering from transhumeral amputation. A novel and first of its kind scheme is proposed which utilizes functional near-infrared spectroscopy (fNIRS) to generate the control commands for a three-degree-of-freedom (DOF) prosthetic arm. The time window for fNIRS signals was set to 1 second. The average accuracy was found to be 82% which is a state-of-the-art result for such a technique. The accuracy ranged from 65 to 85% subject-wise. The data were trained and tested on both artificial neural network (ANN) and linear discriminant analysis (LDA). Eight out of 10 motions were correctly predicted in real time by both classifiers

Comparing Reaction Time and Postural Stabilization based on Activity Groups in Older Adults

The purpose of this study was to compare reaction time and postural stabilization between activity groups in older adults. These variables are important because older adults are at a high fall risk and two major contributors to fall risk are postural stabilization and reaction time. This study examined if the activity group of an older adult had any influence on reaction time and postural stabilization. Fifty-nine older adults aged 66.46 ± 9.47 years old were used in the study. Thirteen subjects were in the master’s athletes which are individuals over the age of 40 who competed in a nationally sanctioned event within the last 6 months and complete at least 150 minutes of aerobic exercise per week, 27 were in recreationally active, which are individuals who complete at least 150 minutes of aerobic exercise per week but do not compete, and 19 were in sedentary activity group, which are individuals who do not exercise at least 150 minutes per week of aerobic exercise. Choice and simple reaction time were measured to determined how quickly the individual could respond to a stimulus. Postural stabilization was measured using a Biodex Balance System. After comparing the activity groups using one-way ANOVA’s, no statistically significant differences were found between activity groups in simple reaction time, F(2, 56) = 2.77, p = .07, choice reaction time F(2, 56) = 2.29, p = .11, or postural stabilization scores F(2, 48) = .697, p = .51. The cohen’s f test found moderate effect sizes in the simple reaction time, f = 0.31, and choice reaction time, f = 0.29. The cohen’s d test found the effect size was largest, d \u3e 0.50 between sedentary and master’s athletes activity groups and between recreationally active and master’s athletes activity groups for all three variables. The main conclusion is that there were no significant differences between activity groups but that may be from the small number of subjects. The effect sizes showed a trend that master’s athletes had the best scores overall for each variable

Exploratory Analysis Of PTSD Severity And Objective Measures Of Physical Activity Among Combat Veterans

Strong levels of motivation, relatedness and self-determination support the likeliness of participating in habitual exercise. Compared to nationwide estimates, research has demonstrated fitness and performance is significantly lower among those suffering from PTSD. Meeting established recommended daily levels of physical activity (PA) for individuals with PTSD is critical for their physical and mental health status over a lifetime and factors supporting or hindering adherence to habitual exercise are lacking. Furthermore, regular PA among combat Veterans with Posttraumatic Stress Disorder (PTSD) is a viable and substantial treatment option to improve physical health status and cognitive well-being. The purpose of this exploratory analysis was to uncover relationships between objectively measured PA and the severity of PTSD symptomology, as established by DSM-V, among trauma-exposed combat Veterans.Methods: PA among a group of combat Veterans (n=10) was monitored for a period of 7-days concurrent to inventories of symptom severity, motives for participation in PA and posttraumatic growth (PTG). Results: Subjects reporting greater symptom severity and currently taking medication demonstrated inferior outcome results versus their counterparts. Conclusion: This was the first study, to our knowledge, to objectively explore PA among Veterans with PTSD. Mixed results suggest moderation of PTG and motives for PA on outcomes for those with PTSD. Activity monitoring in outpatient Veterans with PTSD is feasible. Future studies are warranted

Functional Connectivity During Handgrip Motor Fatigue in Older Adults Is Obesity and Sex-Specific

The prevalence of obesity in older adults, particularly in females, is increasing rapidly and is associated with declines in both the brain and physical health. Both the obese and the female populations have shown greater motor fatigue than their counterparts, however, the central neural mechanisms for fatigue are unclear. The present study measured fatigue-related functional connectivity across frontal and sensorimotor areas using functional near-infrared spectroscopy (fNIRS). Fifty-nine older adults (30 non-obese and 29 obese) performed submaximal handgrip motor fatigue until voluntary exhaustion. Functional connectivity and cerebral hemodynamics were compared across eight cortical areas during motor fatigue and across obesity and sex groups along with neuromuscular fatigue outcomes (i.e., endurance time, strength loss, and force steadiness). Both obesity- and sex-specific functional architecture and mean activation differences during motor fatigue in older adults were observed, which were accompanied by fatigue-related changes in variability of force steadiness that differed between groups. While primary indicators of fatigue, i.e., endurance and strength loss, did not differ between groups, the motor steadiness changes indicated different neural adaptation strategies between the groups. These findings indicate that obesity and sex differences exist in brain function in older adults, which may affect performance during motor fatigue