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Von Baumgarten, R. J.

Publications and source records attributed to Von Baumgarten, R. J..

Physiological response to hyper- and hypogravity during rollercoaster flight

Twenty-six healthy male subjects were flown in a Lear jet aircraft through rollercoaster and parabolic weightlessness flight. Eye movements, respiration, and blood volume pulse were recorded on magnetic tape. The same subjects underwent a battery of five vestibular tests in the laboratory on the ground. One subject in each flight was flown in an upright position, the other in a 90 deg forward tilted head position. The forward tilted subjects always reported motion sickness earlier and after fewer rollercoaster maneuvers than the upright-sitting subjects. It is concluded that the susceptibility to changes of X-axis acceleration is higher than to changes of Z-axis acceleration. Correlation was found between the ability to estimate the subjective vertical (modified Mueller-Aubert-test), optokinetic nystagmus asymmetries, and susceptibility to rollercoaster flight sickness.

Von Baumgarten, R. J.↗

Effect of prehatching weightlessness on adult fish behavior in dynamic environments

At 16-17 months of age, three groups of fish from the embryonated eggs in the ASTP killifish experiment were subjected to postflight tests consisting of rapidly changing environments. It was found that the group of fish with the least amount of development at orbital insertion (A-32) had a decreased rheotropism for both the moving background and the rotating water current tests when compared to ground control fish. Exposure to parabolic aircraft flight conditions revealed that the A-32 fish were less disoriented during zero gravity periods and were hypersensitive to high-gravity periods. These results suggested a modified vestibular competency due to a 9-d prehatching weightlessness exposure.

Hoffman, R. B.↗

Effects of prolonged weightlessness on the swimming pattern of fish aboard Skylab 3

Looping behavior of minnows aboard Skylab 3 is analyzed. Extensive looping patterns were observed at first look on the third day of weightlessness; thereafter, the frequency of the looping episodes diminished until complete adaptation on the twenty-first day, at which time the fish oriented themselves with their backs to the light. The swimming anomaly could be due to (1) absence of continuous bending of sense hairs to a certain extent by gravity, causing the fish to tilt forward in an attempt to increase leverage on the hairs - in the absence of all gravity, tilting is continued into looping (this hypothesis is supported by parabolic flight experiments with partial gravity, in which only tilting was seen); or (2) an attempt by the fish to create a gravitoinertial stimulus by 'centrifuging' its otoliths by looping.

Von Baumgarten, R. J.↗

Vestibular function in the space environment

The present work presents new results about the interdependence of optical illusory sensations and eye movements in man. To establish to what degree certain illusions previously obtained during centrifugation and parabolic flight can be explained by eye movements and by neuronal integration in the brain, real eye movements were measured as they occurred in the dark without optical fixation, during rectilinear accelerations on the ground, and during weightlessness in parabolic flight. Results provide valuable insight into normal vestibular function as well as resolution of within-the-eye and behind-the-eye contributions to the above illusions.

Von Baumgarten, R. J.↗

The gravity reference response, the rotation sensation, and other illusory sensations experienced in aircraft and space flight

An analysis of the gravitational and inertial forces which act during aircraft flight upon the vestibular systems of the aircraft occupants reveals that in the absence of a visual horizon, certain illusory sensations are predictable for various acceleration environments. The 'inversion illusion' (Graybiel and Kellog, 1966) felt by some human subjects at 0 g seems to be different from the rotation sensation and could be caused by the diminished pressure forces of the otoliths on the maculae. The 'inversion illusion' of man correlates well with the blind fish diving behavior observed during aircraft parabolic flight (von Baumgarten et al., 1969, 1972). It is suggested that the fish low g diving response and the human inversion illusion are due to the substitution of a predominantly shearing force of low magnitude as a vestibular reference in place of a normal, predominantly pressure force. This hypothesis indicates that vestibular senses alone cannot provide meaningful postural orientation to simulated or actual gravity of a magnitude below that of earth's gravity.

Shillinger, G. L., Jr.↗

Illusory sensations in aircraft flight and weightlessness

Clearly misleading illusions only appear when the vestibular input is of a nonconflicting nature. A number of experiments with blind goldfish were conducted since the vestibular system of the goldfish is homologous in many respects to that of man. Inertial stimuli were given by linear acceleration of the entire aquarium with the fish in it. A high-speed movie camera and three-axis accelerometers were used to record the fish responses. It was found that fish, if subjected to horizontal linear acceleration, behave as if the moving force acting on the otoliths were a gravitational force component and not an inertial reacting force.

Von Baumgarten, R. J.↗