Millard F. Reschke

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During locomotion, angular head movements act in a compensatory fashion to oppose the vertical trunk translation that occurs during each step in the gait cycle. This coordinated strategy between head and trunk motion serves to aid gaze stabilization and perhaps simplifies the sensory coordinate transformation between the head and trunk, allowing efficient(More)
Our laboratory at the Johnson Space Center has employed the H-reflex recorded from the soleus muscle as a method of monosynaptic reflex testing in conjunction with vertical linear acceleration to assess modification of utriculo-saccular function induced through prolonged exposure to microgravity. It was hypothesized that exposure to free fall would reduce(More)
Space flight represents a form of sensory stimulus rearrangement requiring modification of established terrestrial response patterns through central reinterpretation. Evidence of sensory reinterpretation is manifested as postflight modifications of eye/head coordination, locomotor patterns, postural control strategies, and illusory perceptions of self or(More)
Decreased postural stability is observed in most astronauts immediately following spaceflight. Because ataxia may present postflight operational hazards, it is important to determine the incidence of postural instability immediately following landing and the dynamics of recovery of normal postural equilibrium control. It is postulated that postflight(More)
This article summarizes a variety of newly published findings obtained by the Neuroscience Laboratory, Johnson Space Center, and attempts to place this work within a historical framework of previous results on posture, locomotion, motion sickness, and perceptual responses that have been observed in conjunction with space flight. In this context, we have(More)
Four astronauts experienced passive whole-body rotation in a number of test sessions during a 7-day orbital mission. Pitch (Y-axis) and roll (X-axis) rotation required subject orientations on the rotator in which the otolith system was at radius of 0.5 m. Thus subjects experienced a constant -0.22 Gz stimulus to the otoliths during the 60 s(More)
Postural equilibrium performance by the Skylab 1/2, 3, and 4 crewmen following exposure to weightlessness of 28, 59, and 84 days respectively was evaluated using a modified version of a quantitative ataxia test developed by Graybiel and Fregly. Performance for this test was measured under two sets of conditions. In the first, the crewman was required to(More)
To better understand the effects of varying head movement frequencies on human balance control, 12 healthy adult humans were studied during static and dynamic (0.14, 0.33, 0.6 Hz) head tilts of +/- 30 degrees in the pitch and roll planes. Postural sway was measured during upright stance with eyes closed and altered somatosensory inputs provided by a(More)
Orbital spaceflight exposes astronauts to an environment in which gravity is reduced to negligible magnitudes of 10(-3) to 10(-6) G. Upon insertion into earth orbit, the abrupt loss of the constant linear acceleration provided by gravity removes the otolith stimulus for vestibular sensation of vertical orientation constantly present on Earth. Since the(More)