The Experts below are selected from a list of 20394 Experts worldwide ranked by ideXlab platform
Joseph Mcintyre - One of the best experts on this subject based on the ideXlab platform.
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Weightlessness alters up/down asymmetries in the perception of self-motion
Experimental Brain Research, 2013Co-Authors: Caty De Saedeleer, Mark Lipshits, Ana Maria Cebolla, Ana Bengoetxea, Manuel Vidal, Guy Cheron, Alain Berthoz, Joseph McintyreAbstract:In the present study, we investigated the effect of Weightlessness on the ability to perceive and remember self-motion when passing through virtual 3D tunnels that curve in different direction (up, down, left, right). We asked cosmonaut subjects to perform the experiment before, during and after long-duration space flight aboard the International Space Station (ISS), and we manipulated vestibular versus haptic cues by having subjects perform the task either in a rigidly fixed posture with respect to the space station or during free-floating, in Weightlessness. Subjects were driven passively at constant speed through the virtual 3D tunnels containing a single turn in the middle of a linear segment, either in pitch or in yaw, in increments of 12.5°. After exiting each tunnel, subjects were asked to report their perception of the turn’s angular magnitude by adjusting, with a trackball, the angular bend in a rod symbolizing the outside view of the tunnel. We demonstrate that the strong asymmetry between downward and upward pitch turns observed on Earth showed an immediate and significant reduction when free-floating in Weightlessness and a delayed reduction when the cosmonauts were firmly in contact with the floor of the station. These effects of Weightlessness on the early processing stages (vestibular and optokinetics) that underlie the perception of self-motion did not stem from a change in alertness or any other uncontrolled factor in the ISS, as evidenced by the fact that Weightlessness had no effect on the perception of yaw turns. That the effects on the perception of pitch may be partially overcome by haptic cues reflects the fusion of multisensory cues and top-down influences on visual perception.
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Weightlessness alters up/down asymmetries in the perception of self-motion
Experimental Brain Research, 2013Co-Authors: Caty De Saedeleer, Mark Lipshits, Ana Maria Cebolla, Ana Bengoetxea, Manuel Vidal, Guy Cheron, Alain Berthoz, Joseph McintyreAbstract:In the present study, we investigated the effect of Weightlessness on the ability to perceive and remember self-motion when passing through virtual 3D tunnels that curve in different direction (up, down, left, right). We asked cosmonaut subjects to perform the experiment before, during and after long-duration space flight aboard the International Space Station (ISS), and we manipulated vestibular versus haptic cues by having subjects perform the task either in a rigidly fixed posture with respect to the space station or during free-floating, in Weightlessness. Subjects were driven passively at constant speed through the virtual 3D tunnels containing a single turn in the middle of a linear segment, either in pitch or in yaw, in increments of 12.5°. After exiting each tunnel, subjects were asked to report their perception of the turn’s angular magnitude by adjusting, with a trackball, the angular bend in a rod symbolizing the outside view of the tunnel. We demonstrate that the strong asymmetry between downward and upward pitch turns observed on Earth showed an immediate and significant reduction when free-floating in Weightlessness and a delayed reduction when the cosmonauts were firmly in contact with the floor of the station. These effects of Weightlessness on the early processing stages (vestibular and optokinetics) that underlie the perception of self-motion did not stem from a change in alertness or any other uncontrolled factor in the ISS, as evidenced by the fact that Weightlessness had no effect on the perception of yaw turns. That the effects on the perception of pitch may be partially overcome by haptic cues reflects the fusion of multisensory cues and top-down influences on visual perception.
Caty De Saedeleer - One of the best experts on this subject based on the ideXlab platform.
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Weightlessness alters up/down asymmetries in the perception of self-motion
Experimental Brain Research, 2013Co-Authors: Caty De Saedeleer, Mark Lipshits, Ana Maria Cebolla, Ana Bengoetxea, Manuel Vidal, Guy Cheron, Alain Berthoz, Joseph McintyreAbstract:In the present study, we investigated the effect of Weightlessness on the ability to perceive and remember self-motion when passing through virtual 3D tunnels that curve in different direction (up, down, left, right). We asked cosmonaut subjects to perform the experiment before, during and after long-duration space flight aboard the International Space Station (ISS), and we manipulated vestibular versus haptic cues by having subjects perform the task either in a rigidly fixed posture with respect to the space station or during free-floating, in Weightlessness. Subjects were driven passively at constant speed through the virtual 3D tunnels containing a single turn in the middle of a linear segment, either in pitch or in yaw, in increments of 12.5°. After exiting each tunnel, subjects were asked to report their perception of the turn’s angular magnitude by adjusting, with a trackball, the angular bend in a rod symbolizing the outside view of the tunnel. We demonstrate that the strong asymmetry between downward and upward pitch turns observed on Earth showed an immediate and significant reduction when free-floating in Weightlessness and a delayed reduction when the cosmonauts were firmly in contact with the floor of the station. These effects of Weightlessness on the early processing stages (vestibular and optokinetics) that underlie the perception of self-motion did not stem from a change in alertness or any other uncontrolled factor in the ISS, as evidenced by the fact that Weightlessness had no effect on the perception of yaw turns. That the effects on the perception of pitch may be partially overcome by haptic cues reflects the fusion of multisensory cues and top-down influences on visual perception.
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Weightlessness alters up/down asymmetries in the perception of self-motion
Experimental Brain Research, 2013Co-Authors: Caty De Saedeleer, Mark Lipshits, Ana Maria Cebolla, Ana Bengoetxea, Manuel Vidal, Guy Cheron, Alain Berthoz, Joseph McintyreAbstract:In the present study, we investigated the effect of Weightlessness on the ability to perceive and remember self-motion when passing through virtual 3D tunnels that curve in different direction (up, down, left, right). We asked cosmonaut subjects to perform the experiment before, during and after long-duration space flight aboard the International Space Station (ISS), and we manipulated vestibular versus haptic cues by having subjects perform the task either in a rigidly fixed posture with respect to the space station or during free-floating, in Weightlessness. Subjects were driven passively at constant speed through the virtual 3D tunnels containing a single turn in the middle of a linear segment, either in pitch or in yaw, in increments of 12.5°. After exiting each tunnel, subjects were asked to report their perception of the turn’s angular magnitude by adjusting, with a trackball, the angular bend in a rod symbolizing the outside view of the tunnel. We demonstrate that the strong asymmetry between downward and upward pitch turns observed on Earth showed an immediate and significant reduction when free-floating in Weightlessness and a delayed reduction when the cosmonauts were firmly in contact with the floor of the station. These effects of Weightlessness on the early processing stages (vestibular and optokinetics) that underlie the perception of self-motion did not stem from a change in alertness or any other uncontrolled factor in the ISS, as evidenced by the fact that Weightlessness had no effect on the perception of yaw turns. That the effects on the perception of pitch may be partially overcome by haptic cues reflects the fusion of multisensory cues and top-down influences on visual perception.
Stefan Schneider - One of the best experts on this subject based on the ideXlab platform.
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Sensorimotor performance and haptic support in simulated Weightlessness
Experimental Brain Research, 2020Co-Authors: Bernhard Weber, Michael Panzirsch, Freek Stulp, Stefan SchneiderAbstract:The success of many space missions critically depends on human capabilities and performance. Yet, it is known that sensorimotor performance is degraded under conditions of Weightlessness. Therefore, astronauts prepare for their missions in simulated Weightlessness under water. In the present study, we investigated sensorimotor performance in simulated Weightlessness (induced by shallow water immersion) and whether performance can be improved by choosing appropriate haptic settings of the human–machine interface (e.g., motion damping). Twenty-two participants performed basic aiming and tracking tasks with a force feedback joystick under water and on land and with different haptic settings of the joystick (no haptics, three spring stiffnesses, and two motion dampings). While higher resistive forces should be avoided for rapid aiming tasks in simulated Weightlessness, tracking performance is best with higher motions damping in both land and water setups, although the performance losses due to water immersion cannot be compensated. The overall result pattern also provides insights into the causal mechanism behind the slowing effect during aiming motions and decreased accuracy of tracking motions in simulated Weightlessness. Findings provide evidence that distorted proprioception due to altered muscle spindle activity seemingly is the main trigger of impaired sensorimotor performance in simulated Weightlessness.
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what happens to the brain in Weightlessness a first approach by eeg tomography
NeuroImage, 2008Co-Authors: Stefan Schneider, Vera Brummer, Heather Carnahan, Adam Dubrowski, Christopher D Askew, Heiko K StruderAbstract:Abstract Basic changes in environmental conditions are fundamental to understanding brain cortical mechanisms. Several studies have reported impairment of central nervous processes during Weightlessness. There is ongoing debate as to whether these impairments are attributable to primary physiological effects or secondary psychological effects of the Weightlessness environment. This study evaluates the physiological effects of changed gravity conditions on brain cortical activity. In a first experiment, EEG activity of seven participants was recorded at normal, increased and zero gravity during a parabolic flight. Additionally an EEG under normal gravity conditions preflight was recorded. In a second experiment, 24 participants were exposed to a supine, seated and 9° head-down tilt position while EEG was recorded. Data were analysed using low resolution brain electromagnetic tomography (LORETA). Beta-2 EEG activity (18–35 Hz) was found to be increased in the right superior frontal gyrus under normal gravity conditions inflight. By exposure to Weightlessness a distinct inhibition of this activity within the same areas could be noticed. As the tilt experiment showed changes in the left inferior temporal gyrus in supine and tilted positions we conclude that the observed changes under Weightlessness are not explainable by hemodynamic changes but rather reflect emotional processes related to the experience of Weightlessness. These findings suggest that Weightlessness has a major impact on electro cortical activity and may affect central nervous and adaptation processes.
Si Shao-ya - One of the best experts on this subject based on the ideXlab platform.
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Effects of simulated Weightlessness to the ultrastructures of masseter muscle in rats
Chinese Journal of Prosthodontics, 2013Co-Authors: Si Shao-yaAbstract:Objective: To study the influence of simulated Weightlessness by tail-suspension to the ultrastructures of masseter muscle in rats.Method: 24 Wistar rats were randomly divided into three groups: 1w simulated Weightlessness group,2w simulated Weightlessness group,4w simulated Weightlessness group and control group.All the rats were raised under the same conditions and executed at the one weeks,the two weeks and the four weeks.The histopathological changes and ultrastructures of masseter muscle were observed under microscope and electron microscope respectively.Result: At 1w,2w and 4w,the weight of rats were 328.67±15.65,330.00±12.38 and 326.33±15.88 in the control group and 274.50±41.66,295.00±19.92 and 288.84±22.41 in the experimental groups.The rate of weight decreased,which showed statistically significant difference between the control group and the experimental groups.HE showed that there were the discontinuous Z-line,some dissolved and uneven myofibrils,and the abnormal striated structure in 1w simulated Weightlessness group.We observed no obvious inflammation or solution of muscle fibers in the other groups.By electron microscope,the severe swollen mitochondria with cristae loss,degrade of matrix density and even vacuolus degeneration were found in 1w simulated Weightlessness group.The mitochondria was slight swollen,of which the number increased around the myofibrils in 2w simulated Weightlessness group.There was no obvious swollen in the mitochondria in 4w simulated Weightlessness group.Conclusion: The simulated Weightlessness can lead the reversible injury to the ultrastructures of masseter muscle.
William H Paloski - One of the best experts on this subject based on the ideXlab platform.
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artificial gravity as a countermeasure for mitigating physiological deconditioning during long duration space missions
Frontiers in Systems Neuroscience, 2015Co-Authors: Gilles Clement, Angelia P Bukley, William H PaloskiAbstract:In spite of the experience gained in human space flight since Yuri Gagarin’s historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of Weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the six-month exposure to Weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth’s gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth’s surface, thereby avoiding the physiological deconditioning that takes place in Weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in Weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.
