Journal of Vestibular Research - Volume 7, issue 4

Authors: DiZio, P. | Lackner, J.R. | Mergner, T.

Article Type: Editorial

DOI: 10.3233/VES-1997-7401

Citation: Journal of Vestibular Research, vol. 7, no. 4, pp. 281-282, 1997

Authors: Mittelstaedt, Horst

Article Type: Review Article

Abstract: This article reviews the author’s investigations on the perception and control of spatial relations if the carriers of the relevant sense organs are mobile and controlled independently of each other. In the dragonfly, head rotation is controlled by the head’s inertia, as well as by cervicocollic, optokinetic, and dorsal light reflexes and, in turn, controls trunk rotation by means of neck reflexes on the wings. In humans, invariance of head-referenced visual direction under eye-to-head rotation is attained by feedforward of an efference copy. In the pigeon, invariance of responses to trunk tilt under head-to-trunk rotation is, in flight, achieved by …feedforward of head-to-trunk information yielded by neck receptors. But in standing or walking, this is accomplished by means of gravity sense organs in the trunk. Such organs are also shown to exist in the human trunk by means of experiments on a sled centrifuge. From tests with paraplegic and neuromectomized subjects, it is concluded that truncal graviception 1) is not influenced by mechanoreceptors in the legs, the skin, and between the vertebrae, but 2) is affected by at least two afferent inputs, one originating in the kidneys, another in the tissues that support the large blood vessels against the gravitational load. These conclusions are corroborated by experiments with bilaterally nephrectomized subjects and by means of positive air pressure to the legs, respectively. Recent results under application of positive and negative air pressure to the entire lower body indicate that yet another source of somatic graviception may exist, for example, one that exploits the hydrostatics of blood pressure or the inertia of the mass of the abdominal viscera. Show more

Keywords: neck reflex, efference copy, somatic graviceptor, lower body negative pressure (LBNP), cervicocollic reflex, renal afference, otolith

DOI: 10.3233/VES-1997-7402

Citation: Journal of Vestibular Research, vol. 7, no. 4, pp. 283-302, 1997

Authors: Lackner, James R. | DiZio, Paul

Article Type: Review Article

Abstract: The reafference model has frequently been used to explain spatial constancy during eye and head movements. We have found that its basic concepts also form part of the information processing necessary for the control and recalibration of reaching movements. Reaching was studied in a novel force environment–a rotating room that creates centripetal forces of the type that could someday substitute for gravity in space flight, and Coriolis forces which are side effects of rotation. We found that inertial, noncontacting Coriolis forces deviate the path and endpoint of reaching movements, a finding that shows the inadequacy of equilibrium position models of …movement control. Repeated movements in the rotating room quickly lead to normal movement patterns and to a failure to perceive the perturbing forces. The first movements made after rotation stops, without Coriolis forces present, show mirror-image deviations and evoke perception of a perturbing force even though none is present. These patterns of sensorimotor control and adaptation can largely be explained on the basis of comparisons of efference copy, reafferent muscle spindle, and cutaneous mechanoreceptor signals. We also describe experiments on human iocomotion using an apparatus similar to that which Mittelstaedt used to study the optomotor response of the Eristalis fly. These results show that the reafference principle relates as well to the perception of the forces acting on and exerted by the body during voluntary locomotion. Show more

Keywords: reafference, Coriolis force, reaching, adaptation, force perception, motor control, artificial gravity

DOI: 10.3233/VES-1997-7403

Citation: Journal of Vestibular Research, vol. 7, no. 4, pp. 303-310, 1997

Authors: Howard, Ian P.

Article Type: Review Article

Abstract: This paper reviews five types of interaction between sources of spatial information within and between sense organs; 1) nested, 2) opponent, 3) comparison, 4) covariation, and 5) multicue interactions. Efference copy is treated as a type of sensory input. Examples of each type of interaction are provided, with an emphasis on visual-vestibular interactions. In the first type of interaction, inputs from nested sensory systems are summed like vectors. For instance, the ,3-D vector sum of inputs from the joints and muscle spindles of the arm allows one to judge the position of the hand. In the second type, inputs from …opponent systems are combined to form a signed difference signal with respect to a norm. For instance, the push-pull linkage between the vestibular organs on the two sides of the head provides the signal for head rotation. The third type involves comparisons based on the detection of differences between stimuli presented to different regions of the same sense organ or to distinct sense organs. The fourth type involves the extraction of products or ratios between stimuli used in the detection of invariant high-level features. For instance, the linear size of an object can be derived from the constant product of the distance of the object and the size of its image. Similar systems are used to scale the response to one stimulus feature with respect to a second feature. For instance, vestibular inputs evoking eye nystagmus are scaled by viewing distance. Judgments based on an of the above mechanisms are relational, meaning that they require information from several sources. The fifth type involves multicue systems in which alternative cues are available for the same judgment. The cues are sometimes combined as a weighted mean. For instance, the direction of an object is derived from the mean position of the images in the two eyes, or a judgment of the rotation of the body may be based on combined inputs from the vestibular system and from visual motion. For distinct types of cue, averaging is less common than cue dominance, dissociation, or cue reinterpretation. Show more

Keywords: intersensory, visual-vestibular, vestibular system, opponent processes, sensory integration

DOI: 10.3233/VES-1997-7404

Citation: Journal of Vestibular Research, vol. 7, no. 4, pp. 311-345, 1997

Authors: Mergner, T. | Huber, W. | Becker, W.

Article Type: Review Article

Abstract: The article considers findings and concepts on vestibular-proprioceptive interaction for self-motion perception and postural control under the form of simple describing models. It points out that vestibular-neck interaction is only a small fraction of an extended mechanism of coordinate transformations. This links together the different parts of our bodies, so that sensory information arising in one part of the body can be used for perceptual or motor tasks in other parts. Particular emphasis is put on the problems that arise from imperfect signal transduction in the vestibular semicircular canal systems at low stimulus frequencies/velocities. Also, a “down-and-up-channeling” principle is suggested, …by which the body support is linked via coordinate transformations to the internal notion of physical space provided by the vestibular system. Furthermore, the following question is addressed: how does the brain use visual input to overcome the vestibular deficiencies, at the risk of visual self-motion illusions? Finally, a conceptual model of postural control is presented in which a proprioceptive feedback that links the body to its support surface is merged with a loop for postural stabilization in space. Show more

Keywords: vestibular-neck interaction, proprioception, visual-vestibular interaction, postural control, coordinate transformation, human

DOI: 10.3233/VES-1997-7405

Citation: Journal of Vestibular Research, vol. 7, no. 4, pp. 347-365, 1997