Exposure to the microgravity conditions of space flight induces adaptive modification in the control of vestibularmediated reflexive head movement during locomotion after space flight. Space flight causes astronauts to be exposed to somatosensory adaptation in both the vestibular and body load-sensing (BLS) systems. The goal of these studies was to examine the contributions of vestibular and BLS-mediated somatosensory influences on head movement control during locomotion after long-duration space flight. Subjects were asked to walk on a treadmill driven at 1.8 m/s while performing a visual acuity task. Data were collected using the same testing protocol from three independent subject groups; 1) normal subjects before and after exposure to 30 minutes of 40% bodyweight unloaded treadmill walking, 2) bilateral labyrinthine deficient (LD) patients and 3) astronauts who performed the protocol before and after long duration space flight. Motion data from head and trunk segmental motion data were obtained to calculate the angular head pitch (HP) movements during walking trials while subjects performed the visual task, to estimate the contributions of vestibular reflexive mechanisms in HP movements. Results showed that exposure to unloaded locomotion caused a significant increase in HP movements, whereas in the LD patients the HP movements were significantly decreased. Astronaut subjects' results showed a heterogeneous response of both increases and decreases in the amplitude of HP movement. We infer that BLS-mediated somatosensory input centrally modulates vestibular input and can adaptively modify head-movement control during locomotion. Thus, space flight may cause a central adaptation mediated by the converging vestibular and body load-sensing somatosensory systems.https://ntrs.nasa.gov/search.

The goal of the present study was to investigate the adaptive effects of variation in the direction of optic flow, experienced during linear treadmill walking, on modifying locomotor trajectory. Subjects (n = 30) walked on a motorized linear treadmill at 4.0 kndh for 24 minutes while viewing the interior of a 3D virtual scene projected onto a scrccn 1.5 in in fioct oftheni. Thc virtiial scene depicted constant ~e l f -m~h~n eqiivalent to either 1) walking around the perimeter of a room to one's left (Rotating Room group) 2) walking down the center of a hallway (Infinite Hallway group). The scene was static for the first 4 minutes, and then constant rate self-motion was siniulated for the remaining 20 minutes. Before and after the treadmill locomotion adaptation period, subjects performed five stepping trials where in each trial they marched in place to the beat of a metronome at 90 stepdmin while blindfolded in a quiet room. The subject's final heading direction (deg), final X (for-aft, cm) and final Y (niedio-lateral, cni) positions were measured for each trial. During the treadmill locomotion adaptation period subject's 3D torso position was measured. We found that subjects in the Rotating Room group as compared to the Infinite Hallway group: 1) showed significantly greater deviation during post exposure testing in the heading direction and Y position opposite to the direction of optic flow experienced during treadmill walking 2 ) showed a significant monotonically increasing torso yaw angular rotation bias in the direction of optic flow during the treadmill adaptation exposure period. Subjects in both groups showed greater forward translation (in the +X direction) during the post treadmill stepping task that differed significantly from their pre exposure performance. Subjects in both groups reported no perceptual deviation in position during the stepping tasks. We infer that 3 viewing simulated rotary self-motion during treadmill locomotion causes adaptive modification of sensory-motor integration in the control of position and trajectory during locomotion which functionally reflects adaptive changes in the integration of visual, vestibular, and proprioceptive cues. Such an adaptation in the control of position and heading direction during locomotion due to the congruence of sensory infomiation dcmonstraics the potcritial for adqtive trznsfer between sensorimotor systems and suggests a common neural site for the processing and self-motion perception and concurrent adaptation in motor output. This will result in lack of subjects' perception of deviation of position and trajectory during the post treadmill step test while blind folded.

Objective. This article explores the many factors that have been involved in International Space Station (ISS) on-orbit utilization activities, and the approaches that the National Aeronautics and Space Administration is taking to evaluate, communicate, and maximize the value of these activities. Methods. A review of the initiatives, stakeholders, vehicle assembly, science and technology outcomes, and benefits to Earth and space exploration illustrates the evolving nature of this unique microgravity research platform. Results. The ISS partnership works together to implement many strategic approaches to maximizing the ISS platform so that the full potential of this laboratory is realized.

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The European Columbus and Japanese Kibo laboratories are now fully operational on the International Space Station (ISS), bringing decades of international planning to fruition. NASA is now completing launch and activation of major research facilities that will be housed in the Destiny U.S. Laboratory, Columbus, and Kibo. These facilities include major physical sciences capabilities for combustion, fluid physics, and materials science, as well as additional multipurpose and supporting infrastructure. Expansion of the laboratory space and expansion to a 6-person crew (May 2009), is already leading to significant increases in research throughput even before assembly is completed. International research on the ISS includes exchanges of results, sharing of facilities, collaboration on experiments, and joint publication and communication of accomplishments. Significant and ongoing increases in research activity on ISS have occurred over the past year. Although research results lag behind on-orbit operations by 2-5 years, the surge of early research activities following Space Shuttle return to flight in 2005 is now producing an accompanying surge in scientific publications. Evidence of scientific productivity from early utilization opportunities combined with the current pace of research activity in orbit are both important parts of the evidence base for evaluating the potential future achievements of a complete and active ISS.