Human Performance in a Realistic Instrument-Control Task during Short-Term Microgravity.

Previous studies have documented the detrimental effects of microgravity on human sensorimotor skills. While that work dealt with simple, laboratory-type skills, we now evaluate the effects of microgravity on a complex, realistic instrument-control skill. Twelve participants controlled a simulated power plant during the short-term microgravity intervals of parabolic flight as well as during level flight.

Motor imagery: lessons learned in movement science might be applicable for spaceflight.

Before participating in a space mission, astronauts undergo parabolic-flight and underwater training to facilitate their subsequent adaptation to weightlessness. Unfortunately, similar training methods can't be used to prepare re-adaptation to planetary gravity. Here, we propose a quick, simple and inexpensive approach that could be used to prepare astronauts both for the absence and for the renewed presence of gravity.

Essential Hypertension: Cardiovascular Response to Breath Hold Combined with Exercise.

Essential hypertension (EH) is a widespread disease and might be prevalent in apnea divers and master athletes. Little is known about the influence of EH and the antihypertensive drugs (AHD) on cardiovascular reactions to combined breath hold (BH) and exercise. In this pilot study, healthy divers (HCON) were compared with treated hypertensive divers with regard to heart rate (HR) and mean blood-pressure (MAP) responses to BH, exercise and the combination of both.

Does Visuomotor Adaptation Proceed in Stages? An Examination of the Learning Model by Chein and Schneider (2012).

A new 3-stage model based on neuroimaging evidence is proposed by Chein and Schneider (2012). Each stage is associated with different brain regions, and draws on cognitive abilities: the first stage on creativity, the second on selective attention, and the third on automatic processing. The purpose of the present study was to scrutinize the validity of this model for 1 popular learning paradigm, visuomotor adaptation.

Persistent Postconcussive Symptoms Are Accompanied by Decreased Functional Brain Oxygenation.

Diagnostic methods are considered a major concern in the determination of mild traumatic brain injury. The authors examined brain oxygenation patterns in subjects with severe and minor persistent postconcussive difficulties and a healthy control group during working memory tasks in prefrontal brain regions using functional near-infrared spectroscopy. The results demonstrated decreased working memory performances among concussed subjects with severe postconcussive symptoms that were accompanied by decreased brain oxygenation patterns.

Oxygen uptake and heart rate kinetics during dynamic upper and lower body exercise: an investigation by time-series analysis.

Purpose: The study compared the kinetic responses of heart rate (HR), pulmonary ([Formula: see text]O2pulm) and muscular oxygen uptake ([Formula: see text]O2musc) for upper (UpBody) and lower body (LoBody) exercise.

Methods: Eleven healthy men (24 ± 2 years, 184 ± 8 cm, 79 ± 7 kg) performed pseudo-random binary sequence (PRBS) work rate (WR) changes on a semi-recumbent cycle ergometer (30 and 80 W) and an arm cranking exercise device (20 and 50 W); followed by stepwise increases in WR (UpBody: 20 W 5 min(-1); LoBody: 50 W 5 min(-1)). [Formula: see text]O2pulm was measured breath-by-breath and HR beat-to-beat.

Mental rotation of letters, body parts and scenes during whole-body tilt: role of a body-centered versus a gravitational reference frame.

It is known that in mental-rotation tasks, subjects mentally transform the displayed material until it appears "upright" and then make a judgment. Here we evaluate, by using three typical mental rotation tasks with different degrees of embodiment, whether "upright" is coded to a gravitational or egocentric reference frame, or a combination of both. Observers stood erect or were whole-body tilted by 60°, with their left ear down.

Context-dependent neuroelectric responses during motor control.

Research on brain responses during motor control is usually performed under typical laboratory settings. However, everyday life and the laboratory differ in many aspects, such as purposeful and motivated behavior; and there's no awareness of "being measured" in everyday life. In the laboratory, movements are usually explicitly instructed, overtly measured and follow no intrinsic motivated purpose.

Subliminal primes for global or local processing influence judgments of vehicular traffic.

Previous studies on semantic priming show that briefly presented words can unconsciously manipulate subjects' mental states, behaviors, and attitudes. Here we evaluated whether semantic primes can also manipulate the breadth of subjects' visual attention. We primed participants with briefly presented words that indicate either broadness or narrowness; each prime was followed by either a large or a small picture of a street intersection with vehicles, and participants had to indicate in which order the vehicles were legally allowed to pass the intersection.

A comparison of sensorimotor adaptation in the visual and in the auditory modality.

We compared sensorimotor adaptation in the visual and the auditory modality. Subjects pointed to visual targets while receiving direct spatial information about fingertip position in the visual modality, or they pointed to visual targets while receiving indirect information about fingertip position in the visual modality, or they pointed to auditory targets while receiving indirect information about fingertip position in the auditory modality. Feedback was laterally shifted to induce adaptation, and aftereffects were tested with both target modalities and both hands.

Results of a workplace health campaign: what can be achieved?

Background: Effective health promotion in the workplace is now essential because of the rising health-related costs for businesses, the increasing pressure arising from international competition, prolonged working lives, and the aging of the work force. The basic problem of prevention campaigns is that the target groups are too rarely reached and sustainable benefits too rarely achieved. In 2011, we carried out a broad-based health and fitness campaign to assess how many personnel could be motivated to participate in a model study under nearly ideal conditions.

Age-related changes in prefrontal activity during walking in dual-task situations: a fNIRS study.

Background: Previous studies suggest that the human gait is under control of higher-order cognitive processes, located in the frontal lobes, such that an age-related degradation of cognitive capabilities has a negative impact on gait.

Methods: Using functional Near-Infrared-Spectroscopy (fNIRS) we investigate the frontocortical hemodynamic correlates of dual-task walking in two conditions. 15 young and 10 older individuals walked on a treadmill while completing concurrent tasks that had either visual (checking) or verbal-memory (alphabet recall) demands.

Does the walking task matter? Influence of different walking conditions on dual-task performances in young and older persons.

Previous literature suggests that age-related deficits of dual-task walking are particularly pronounced with second tasks that require continuous visual processing. Here we evaluate whether the difficulty of the walking task matters as well. To this end, participants were asked to walk along a straight pathway of 20m length in four different walking conditions: (a) wide path and preferred pace; (b) narrow path and preferred pace, (c) wide path and fast pace, (d) obstacled wide path and preferred pace.

The context dependence of grasping movements: an evaluation of possible reasons.

Laboratory experiments typically examine grasping movements as isolated motor acts executed for their own sake. In real life, however, grasping is often part of complex and meaningful movement sequences. We have shown before that grasping characteristics differ substantially between these two behavioral contexts and that these differences can be reduced to five orthogonal factors.

EEG coherence during mental rotation of letters, hands and scenes.

The purpose of the present study was to investigate differences in the electrocortical synchronization pattern during mental rotation of three different object categories as well as six different rotation angles. Therefore, event-related coherence of the electroencephalographic (EEG) activity between selective frontal and parietal electrode pairs of ten subjects was measured during the performance of a mental rotation task consisting of rotation of letters, hands and scenes. Statistical analysis showed an increased coherence of frontal and parietal electrode pairs for the condition LETTER in comparison to the other conditions in the alpha1- (8.

Context dependence of manual grasping movements in near weightlessness.

Background: We have shown before that human subject grasping performance differs in an everyday-like context with that observed in a laboratory context. The purpose of the present study was to determine whether reported deficits in weightlessness are more pronounced when grasping is performed as part of everyday-like behavior rather than as an isolated laboratory-type response.

Methods: The grasping performance of 12 participants (ages 29 +/- 5 yr) during periods of near weightlessness in parabolic flights was compared.

Inverse relationship between task complexity and performance deficit in 5 m water immersion.

Previous research on cognitive deficits during shallow water immersion led to inconsistent results: some authors observed deficits at 5 m, but others only at depths well beyond 5 m. The present study evaluates whether this discrepancy could be related to different levels of difficulty. Forty-eight subjects participated in a mental rotation task and in a color-word task, both having multiple levels of difficulty.

Basic principles of sensorimotor adaptation to different distortions with different effectors and movement types: a review and synthesis of behavioral findings.

This article reviews seemingly conflicting behavioral data about sensorimotor adaptation. Some earlier studies assert that one common mechanism exists for multiple distortions, and others that multiple mechanisms exist for one given distortion. Some but not others report that adaptation is direction-selective.

Characteristics of grasping movements in a laboratory and in an everyday-like context.

To understand the principles of motor control, it is useful to know whether movements with the same physical constraints can be governed by different rules depending on the behavioral context. We therefore have recently introduced a paradigm in which subjects grasp from the same starting position to the same final object, once as a typical laboratory task and once as part of everyday-like behavior. In the laboratory context, grasping was repetitive, externally triggered and purposeless; in the everyday-like context, it was embedded in a complex activity, intentionally initiated, and served a purpose.

Changed joint position sense and muscle activity in simulated weightlessness by water immersion.

Background: Previous studies suggested that proprioceptive feedback for passive arm positioning and isometric forces deteriorates under water. Here we investigate whether a similar deficit exists for active arm positioning. Since deficits were attributed to a reduced muscle tone but findings about muscle tone in water are ambiguous, we re-evaluated this issue.

Skeletal muscle VO₂ kinetics from cardio-pulmonary measurements: assessing distortions through O₂ transport by means of stochastic work-rate signals and circulatory modelling.

During non-steady-state exercise, dynamic changes in pulmonary oxygen uptake (VO₂pulm) are dissociated from skeletal muscle VO₂ (VO₂musc) by changes in lung and venous O₂ concentrations (CvO₂), and the dynamics and distribution of cardiac output (CO) between active muscle and remaining tissues (Qrem). Algorithms can compensate for fluctuations in lung O₂ stores, but the influences of CO and CvO₂ kinetics complicate estimation of VO₂musc from cardio-pulmonary measurements. We developed an algorithm to estimate VO₂musc kinetics from VO₂pulm and heart rate (HR) during exercise.

Influence of cognitive functions and behavioral context on grasping kinematics.

We have documented before that human grasping movements executed in an everyday-like context differ from those in a typical laboratory context. The differences were reduced by factor analysis to five orthogonal factors; we took this as evidence that at least five distinct sensorimotor functions are context-dependent. To better understand how context exerts its influence on the sensorimotor system, we now evaluate the relationship between context-dependence and cognitive abilities.

Physical fitness, weight, smoking, and exercise patterns in young adults.

Introduction: The health and physical fitness of adolescents and young adults are important not just to the individuals concerned, but also to society as a whole. Many studies from many different countries have dealt with the prevalence of overweight, the risk factors for it, and the morbidity it causes, but no more than a few have addressed the effects of unhealthy lifestyles on physical fitness. In this study, we show that young adults' physical performance depends on the number of risk factors they possess.

Mental rotation of a letter, hand and complex scene in microgravity.

Previous studies showed egocentric but not allocentric mental rotation tasks to be impaired in microgravity when feedback cues about vertical surroundings were restricted. Those studies are difficult to reconcile, however, since they were limited not only to small subject groups, but also differed dramatically in design. According to this lack, the present study was conducted in order to compare three typical egocentric and allocentric mental rotation stimuli in microgravity within a single experiment and using the same subjects and setup conditions.