Brain function and exercise. Current perspectives

[Virtual reality technology as a promising direction in neurorehabilitation]

Nervous system damage affects more than a billion people worldwide and is one of the leading causes of cognitive impairment. An urgent issue in modern medicine is the neurorehabilitation of this particular group of patients. The purpose of this article is to search for new approaches to achieve more effective recovery of cognitive functions, precisely by using virtual reality technology as a promising direction in neurorehabilitation. It has been shown that neurobiological effects of virtual reality have a positive effect on the plasticity of neurons, improve cognitive functions and positively affect the psychoemotional state. A case of the positive impact of being in the virtual environment «Outer Space» in a female patient with cognitive impairment and chronic pain is presented.

Virtual Reality for Neurorehabilitation and Cognitive Enhancement

Our access to computer-generated worlds changes the way we feel, how we think, and how we solve problems. In this review, we explore the utility of different types of virtual reality, immersive or non-immersive, for providing controllable, safe environments that enable individual training, neurorehabilitation, or even replacement of lost functions. The neurobiological effects of virtual reality on neuronal plasticity have been shown to result in increased cortical gray matter volumes, higher concentration of electroencephalographic beta-waves, and enhanced cognitive performance. Clinical application of virtual reality is aided by innovative brain–computer interfaces, which allow direct tapping into the electric activity generated by different brain cortical areas for precise voluntary control of connected robotic devices. Virtual reality is also valuable to healthy individuals as a narrative medium for redesigning their individual stories in an integrative process of self-improvement and personal development. Future upgrades of virtual reality-based technologies promise to help humans transcend the limitations of their biological bodies and augment their capacity to mold physical reality to better meet the needs of a globalized world.

Induced gamma band activity from EEG as a possible index of training-related brain plasticity in motor tasks

The aim of this study was proposing gamma band activity (GBA) as an index of training-related brain plasticity in the motor cortex. Sixteen controls underwent an experimental session where electroencephalography (EEG) activity was recorded at baseline (resting) and during a motor task (hand movements). GBA was obtained from the EEG data at baseline and during the task. Index of plasticity (IP) was defined as the relationship between GBA at the end of the motor task (GBAM_FIN), divided by GBA at the beginning of the task (GBAM_INI) for movements of both hands. There was a significant increase in GBA at the end of the task, compared to the initial GBA for the motor task (GBAM_FIN > GBAM_INI). No differences were found at baseline (GBAB_FIN ≈ GBAB_INI). Individual IP values had a positive (r = 0.624) and significant correlation with subject's handedness. Due to plastic changes, GBA could indirectly but objectively reveal changes in cerebral activity related to physical training. This method could be used as a future diagnostic test in the follow-up of patients undergoing rehabilitation. It could also have potential applications in the fields of sports medicine.

Nurturing and Pampering Paradigm for Office Ergonomics

This paper proposes that current ergonomic practices for design of sedentary jobs, focusing on comfort and support, are inadequate to create healthy and productive workplaces. In fact, they may be counter-productive over the long term. The key results from several research investigations supporting this proposition are: 1) Comfortable workstations adjusted to the user, along with training and education, were inadequate to relieve potentially harmful spinal stress and circulatory impedance caused by sedentary jobs (Paul, 1995; Paul and Helander, 1995). 2) Sedentary jobs induced cognitive mood states like drowsiness and lack of alertness that degrade cognitive function and performance (Paul, 1995b). 3) Activity and movement, for example, between sitting and standing, significantly reduced spinal stress and improved blood circulation (Paul, 1995a; Paul and Helander, 1996a). They also improved mood states linked with superior mental performance (Paul, 1995b; Paul, Morrow and Helander, 1996) 4) Excessively comfortable sedentary work settings induce mood states that could be detrimental to cognitive performance (Paul, Morrow and Helander, 1996). 5) Comfort and discomfort are not two ends of an evaluative spectrum, but rather two orthogonal constructs with two sets of casual factors (Zhang and Helander, 1992). These results collectively provided foundation for the nurturing and pampering paradigm. In this paradigm, nurturing is the strategy to reduce discomfort and pampering is the strategy to apply comfort. Nurturing promotes active, dynamic use of the body during workday to maintain health and prevent injuries. It is discussed using phrases like ‘the best posture is the next posture’ or ‘use it or lose it.’ Pampering with aesthetic and plush environments that induce comfortable perceptions, on the other hand, is a motivational tool with an inverted-U relationship to performance. Utility of this paradigm to create healthy and productive work settings and reduce occupational injuries is supported with several studies from diverse fields. Finally, its implications for workplace design and limitations are discussed.

Incremental Exercise, Plasma Concentrations of Catecholamines, Reaction Time, and Motor Time during Performance of a Noncompatible Choice Response Time Task

The primary purpose was to examine the effect of incremental exercise on a noncompatible response time task. Participants ( N = 9) undertook a 4-choice noncompatible response time task under 3 conditions, following rest and during exercise at 70% and 100% of their maximum power output. Reaction and movement times were the dependent variables. Maximum power output had been previously established on an incremental test to exhaustion. A repeated-measures multivariate analysis of variance yielded a significant effect of exercise intensity on the task, but observation of the separate univariate repeated-measures analyses of variance showed that only movement time was significantly affected. Post hoc Tukey tests indicated movement time during maximal intensity exercise was significantly faster than in the other two conditions. The secondary purpose of the study was to assess whether increases in plasma concentrations of adrenaline and nor-adrenaline during exercise and power output would act as predictor variables of reaction and movement times during exercise. Catecholamine concentrations were based on venous blood samples taken during the maximum power output test. None of the variables were significant predictors of reaction time. Only power output was a significant predictor of movement time ( R2 = .24). There was little support for the notion that peripheral concentrations of catecholamines directly induce a central nervous system response.

Effects of high vs. low cadence training on cyclists' brain cortical activity during exercise

OBJECTIVES

As brain cortical activity depends on cadence, exercise at different pedaling frequencies could provide efficient stimuli for functional adaptations of the brain. Therefore, the purpose of the study was to investigate the effects of cadence-specific training on brain cortical activity as well as endurance performance.

DESIGN

Randomized, controlled experimental trial in a repeated measure design.

METHODS

Male (n=24) and female (n=12) cyclists were randomly assigned to either a high cadence group (HCT), a low cadence group (LCT) or a control group (CON) for a 4 week intervention period. All groups performed 4h of basic endurance training per week. Additionally, HCT and LCT completed four cadence-specific 60min sessions weekly. At baseline and after 4 weeks subjects performed an incremental test with spirometry as well as an interval session (constant load; varying cadences) with continuous recording of electroencephalographic (EEG) rhythms.

RESULTS

In contrast to CON, HCT and LCT elicited similar improvements of maximal oxygen uptake and power at the individual anaerobic threshold. Additionally, there was a reduction of alpha-, beta- and overall-power spectral density in HCT, which was more pronounced at high cadences. Improvements of endurance performance were correlated with reductions of EEG spectral power at 90 and 120rpm.

CONCLUSIONS

Whereas high and low cadence training elicit similar improvements in endurance performance, brain cortical activity is especially sensitive to high cadence training. Its reduction can be interpreted in the sense of the neural efficiency hypothesis and might as well influence the sensation of central fatigue positively.

Cardiorespiratory fitness and brain diffusion tensor imaging in adults over 80 years of age

A positive association between cardiorespiratory fitness (CRF) and white matter integrity has been consistently reported in older adults. However, it is unknown whether this association exists in adults over 80 with a range of chronic disease conditions and low physical activity participation, which can influence both CRF and brain health. This study examined whether higher CRF was associated with greater microstructural integrity of gray and white matter in areas related to memory and information processing in adults over 80 and examined moderating effects of chronic diseases and physical activity. CRF was measured as time to walk 400 m as quickly as possible with concurrent 3T diffusion tensor imaging in 164 participants (57.1% female, 40.3% black). Fractional anisotropy (FA) was computed for cingulum, uncinate and superior longitudinal fasciculi. Mean diffusivity (MD) was computed for dorsolateral prefrontal cortex, hippocampus, parahippocampus, and entorhinal cortex. Moderating effects were tested using hierarchical regression models. Higher CRF was associated with higher FA in cingulum and lower MD in hippocampus and entorhinal cortex (β, sex-adjusted p: -0.182, 0.019; 0.165, 0.035; and 0.220, 0.006, respectively). Hypertension attenuated the association with MD in entorhinal cortex. Moderating effects of chronic diseases and physical activity in walking and climbing stairs on these associations were not significant. The association of higher CRF with greater microstructural integrity in selected subcortical areas appears robust, even among very old adults with a range of chronic diseases. Intervention studies should investigate whether increasing CRF can preserve memory and information processing by improving microstructure and potential effects of hypertension management.

Effects of exercise on memory consolidation and retrieval of passive avoidance learning in young male rats

Purpose

Previous studies have shown that physical activity improves learning and memory. Present study was performed to determine the effects of short term and long term treadmill exercise on learning, memory consolidation and retrieval of passive avoidance learning in an animal model.

Methods

In this study fifty male Wistar rats with 3-4 months of age were randomly divided into five groups (n=10 in each group). Control group was trained in passive avoidance box and was tested 10 min, 24 hr, 10 days and 3 months later. Two groups exercised on treadmill one hour at 17 m. min for 10 days and 3 months respectively and then were trained in passive avoidance box and were tested 10 min and 24 hr later. The other two groups were trained and were tested 10 days and 24 hr later and then exercised on treadmill as same as other exercised groups.

Results

Obtained results showed that short-term (10 days) and long-term (3 months) treadmill running before training by passive avoidance test had significant (P=0.006 and P=0.001 respectively) effects on memory consolidation. However, no significant difference was observed between latency time of rats before and after exercise in exercised groups retrieval (P>0.05).

Conclusion

Our results showed that physical activity promoted learning and memory consolidation but it did not affect retrieval memory performance.

Beta and alpha electroencephalographic activity changes after acute exercise

Exercise has been widely related to changes in cortical activation and enhanced brain functioning. Quantitative electroencephalography (qEEG) is frequently used to investigate normal and pathological conditions in the brain cortex. Therefore, the aim of the present study was to observe absolute power alterations in beta and alpha frequency bands after a maximal effort exercise. Ten healthy young volunteers were submitted to an eight-minute resting EEG (eyes closed) followed by a maximal exercise test using a mechanical cycle ergometer. Immediately after the exercise, another identical eight-minute EEG was recorded. Log transformation and paired student's t-test compared the pre and post exercise values (p<0.05). Results indicated a significant absolute power increase in beta after exercise at frontal (Fp1, F3 and F4) and central (C4) areas, which might be related to increased cortical activation.

Psychological and physiological effects of 24-style taijiquan

This study was conducted to determine whether 24-style Taijiquan (24TJQ) exhibits measurable psychological and physiological effects. Twenty-two middle-aged female subjects performed 24TJQ and cycle ergometry exercises at the same intensity determined by the same heart rate during 2 exercises. Electroencephalography and Profile of Mood State (POMS) were monitored before and after 2 exercises. The responses to 24TJQ exercise were different from those to cycle ergometry exercise when the heart rate returned to the resting level: (1) alpha increased and theta decreased significantly in the frontal region, while theta decreased significantly in the central and occipital regions; (2) in the POMS test, an improved positive mood was found following 2 exercises, while negative mood was suppressed following 24TJQ exercise; (3) significant correlations were found between the increased alpha in the frontal region, the decreased theta in the central or occipital region and the vigor of the POMS test. These results suggest that 24TJQ exercise induced a resting awakening state and exhibited a relaxing effect on both mind and body.

Protocol for Project FACT: a randomised controlled trial on the effect of a walking program and vitamin B supplementation on the rate of cognitive decline and psychosocial wellbeing in older adults with mild cognitive impairment [ISRCTN19227688]

Background

the prevalence of individuals with cognitive decline is increasing since the number of elderly adults is growing considerably. The literature provides promising results on the beneficial effect of exercise and vitamin supplementation on cognitive function both in cognitively healthy as well as in the demented elderly.

Methods/Design

the design is a two-by-two factorial randomised controlled trial. The study population consists of independently living elderly, between 70 and 80 years old, with mild cognitive impairment (MCI). In the RCT the effect of two interventions, a walking program and vitamin supplementation, is examined. The walking program (WP) is a group-based program aimed at improving cardiovascular endurance; frequency two lessons a week; lesson duration one hour; program duration one year. Non-walking groups receive a placebo activity program (PAP) (i.e. low intensive non-aerobic group exercises, like stretching) with the same frequency, lesson and program duration. Vitamin supplementation consists of a single daily vitamin supplement containing 50 mg B6, 5 mg folic acid and 0,4 mg B12 for one year. Subjects not receiving vitamin supplements are daily taking an identically looking placebo pill, also for a year. Participants are randomised to four groups 1) WP and vitamin supplements; 2) WP and placebo supplements; 3) PAP and vitamin supplements; 4) PAP and placebo supplements. Primary outcome measures are measures of cognitive function. Secondary outcomes include psychosocial wellbeing, physical activity, cardiovascular endurance and blood vitamin levels.

Discussion

no large intervention study has been conducted yet on the effect of physical activity and vitamin supplementation in a population-based sample of adults with MCI. The objective of the present article is to describe the design of a randomised controlled trial examining the effect of a walking program and vitamin B supplementation on the rate of cognitive decline in older adults with MCI.

Increase in reaction time for the peripheral visual field during exercise above the ventilatory threshold

The purpose of the present study was to determine whether reaction time (RT) for the peripheral visual field increases at exercise intensity above the ventilatory threshold (VT) during incremental exercise and to examine the relationship between aerobic capacity and the extent of increase in the RT. Nine healthy subjects performed a simple manual RT task for the peripheral visual field at rest, during exercise on a cycle ergometer, and immediately after exercise. After warm-up exercise, the subjects cycled at 40 W for 3 min, increasing by 40 W every 3 min until 240 W in a step-wise manner. During incremental exercise, RT measurements were performed 1 min and 30 s after the start of every increase in workload. The RT for the peripheral visual field significantly increased at exercise intensity above VT, as compared with at rest. The increase in the RT, which was calculated by subtracting the RT at rest from the RT at 240 W, negatively correlated with maximal oxygen uptake VO(2max) for each subject (r = -0.73, P < 0.05). It is likely that high aerobic capacity attenuates the increase in the RT for the peripheral visual field during exhaustive exercise.

Debunking a myth: neurohormonal and vagal modulation of sleep centers, not redistribution of blood flow, may account for postprandial somnolence

It is widely believed that postprandial somnolence is caused by redistribution of blood flow from cerebral to mesenteric vessels after a meal. This belief persists despite its apparent contradiction with a well-known neurophysiologic principle that cerebral perfusion is preferentially maintained under a wide range of physiologic states. For instance, during exercise when a large amount of perfusion is diverted to muscles, blood flow to the brain is maintained. Furthermore, recent evidence suggests that there is no measurable change of blood flow in the common carotid artery during postprandial states. We propose an alternative hypothesis that postprandial release of gut-brain hormones and activation of vagal afferents may play a role in postprandial somnolence through modulation of sleep centers such as the hypothalamus. Feeding alters the milieu of hormones such as melatonin and orexins and also promotes central vagal activation. Emerging evidence suggest that these pathways are also modulators of neural sleep centers. Potential adaptive explanations of postprandial somnolence are explored from a Darwinian perspective.

Cerebral changes during exercise in the heat

This review focuses on cerebral changes during combined exercise and heat stress, and their relation to fatigue. Dynamic exercise can elevate the core temperature rapidly and high internal body temperatures seem to be an independent cause of fatigue during exercise in hot environments. Thus, in laboratory settings, trained participants become exhausted when they reach a core temperature of approximately 40 degrees C. The observation that exercise-induced hyperthermia reduces the central activation percentage during maximal isometric muscle contractions supports the idea that central fatigue is involved in the aetiology of hyperthermia-induced fatigue. Thus, hyperthermia does not impair the ability of the muscles to generate force, but sustained force production is lowered as a consequence of a reduced neural drive from the CNS. During ongoing dynamic exercise in hot environments, there is a gradual slowing of the electroencephalogram (EEG) whereas hyperthermia does not affect the electromyogram. The frequency shift of the EEG is highly correlated with the participants' perception of exertion, which furthermore may indicate that alterations in cerebral activity, rather than peripheral fatigue, are associated with the hyperthermia-induced development of fatigue. Cerebral blood flow is reduced by approximately 20% during exercise with hyperthermia due to hyperventilation, which causes a lowering of the arterial CO(2) pressure. However, in spite of the reduced blood flow, cerebral glucose and oxygen uptake does not seem to be impaired. Removal of heat from the brain is also an important function of the cerebral blood flow and the lowered perfusion of the brain during exercise and heat stress appears to reduce heat removal by the venous blood. Heat is consequently stored in the brain. The causal relationship between the circulatory changes, the EEG changes and the hyperthermia-induced central fatigue is at the present not well understood and future studies should focus on this aspect.

Effect of long-term swimming exercise on somatosensory evoked potentials in rats

The study investigated whether long-term swimming exercise prevents age-related changes in rat somatosensory evoked potentials (SEPs) and somatosensory cortex (SC) morphology. A total of 25 9-month-old rats were assigned to an exercise or control group. The exercise group swam 1 h/day five times weekly for 1 year. The results showed that long-term exercise prevented age-related changes in SEPs and SC morphology.

Improving cognitive function after brain injury: the use of exercise and virtual reality

OBJECTIVE

To assess the impact of exercise and virtual reality (VR) on the cognitive rehabilitation of persons with traumatic brain injury (TBI).

DESIGN

Before-after trial assessed cognitive function after a 4-week intervention program. A random allocation crossover assessed changes in reaction and movement times after a single bout of VR exercise and a no-exercise control condition.

SETTING

Brain injury rehabilitation unit in Edinburgh, Scotland.

PATIENTS

(1) Four-week intervention: a consecutive sample of 13 suitable TBI adults were compared to control populations (n > 25) of previous TBI patients of similar age, severity, and time postinjury. (2) Single-bout intervention: a consecutive sample of 13 suitable adults with moderate TBI, 6.29 to 202.86 weeks postinjury.

INTERVENTION

Nonimmersive VR exercise.

MAIN OUTCOME MEASURES

(1) Tests of attention, information processing, learning, and memory. (2) Reaction and movement times.

RESULTS

After the 4-week intervention patients performed significantly better than controls on the digit symbol (p < .01). verbal (p < .01), and visual learning tasks (p < .05). Significant improvements in reaction times (p < .01) and movement times (p < .05) were gained following a single bout of VR exercise.

CONCLUSION

Exercising in a virtual environment offers the potential for significant gains in cognitive function.