Implications of Recent Developments in Dynamic Spatial Orientation and Visual Resolution for Vehicle Guidance

Leibowitz, Herschel W.; Post, Robert B.; Brandt, Th.; Dichgans, J.

doi:10.1007/978-1-4613-3569-6_8

Cited by 34 publications

(17 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Interfacing Ego-and Object-motion Perception and Visual-vestcontrasting

confidence: 77%

“…Note that this means that slow phase nystagmus eye movements do in fact generate efference copies in reference signals in which only 72% of V eyes s is registered, just as in the case of pursuit eye movements. This finding is at variance with the traditional view, mentioned earlier, that nystagmoid eye movements do not generate efference copy signals (Howard & Templeton 1966;Johnstone & Mark 1970;1973;Kornhuber 1974;Leibowitz et al 1982;Raymond et al 1984; but see Bedell et al, 1989, and Mittelstaedt, 1990, for experimental findings and theoretical views that agree with the present observation).Since in this experiment subjects were rotated along their vertical axis in total darkness, the V head s term in Equation 19 actually reflects the gain of semicircular canal afferents (although some kinaesthetic feedback may also have been present). The small (7%) overregistration of head velocity in these afferents explains the oculogyral illusion (when an observer is rotated in complete darkness and nystagmus is suppressed with a head stationary fixation point, this fixation point, rotating with the observer, seems to move slightly faster than the observer, see, e.g., Eisner 1971; Graybiel & Hupp 1946;Howard 1982;Ross 1974;Whiteside et al 1965): the velocity of the fixation point in space is overestimated because it corresponds to the difference between a zero retinal and a slightly oversized reference signal.…”

contrasting

confidence: 83%

See 1 more Smart Citation

What does linear vection tell us about the optokinetic pathway?

Sauvan

1994

Behav Brain Sci

View full text Add to dashboard Cite

According to the traditional inferential theory of perception, percepts of object motion or stationarity stem from an evaluation of afferent retinal signals (which encode image motion) with the help of extraretinal signals (which encode eye movements). According to direct perception theory, on the other hand, the percepts derive from retinally conveyed information only. Neither view is compatible with a perceptual phenomenon that occurs during visually induced sensations of ego motion (vection). A modified version of inferential theory yields a model in which the concept of extraretinal signals is replaced by that of reference signals, which do not encode how the eyes move in their orbits but how they move in space. Hence reference signals are produced not only during eye movements but also during ego motion (i.e., in response to vestibular stimulation and to retinal image flow, which may induce vection). The present theory describes the interface between self-motion and object-motion percepts. An experimental paradigm that allows quantitative measurement of the magnitude and gain of reference signals and the size of the just noticeable difference (JND) between retinal and reference signals reveals that the distinction between direct and inferential theories largely depends on: (1) a mistaken belief that perceptual veridicality is evidence that extraretinal information is not involved, and (2) a failure to distinguish between (the perception of) absolute object motion in space and relative motion of objects with respect to each other. The model corrects these errors, and provides a new, unified framework for interpreting many phenomena in the field of motion perception.Keywords: direct perception; efference copy; inference; motion perception; self-motion; velocity perception; visual-vestibular interactions Inferential versus direct perceptionHow do we maintain the visual percept of a stable world while images of our environment move across the retinae during eye movements? Answers to this question can be classified in two main theoretical approaches. According to the traditional view, here called inferential theory, we perceive the motion or stationarity of an object, or of the visual world itself, on the basis of the outcome of a comparison between two neural signals (see e.g., Helmholtz 1910;Jeannerod et al. 1979;MacKay 1972; Mittelstaedt 1990;Sperry 1950;Von Hoist & Mittelstaedt 1950). One signal, here to be called the retinal signal, consists of retinal afferents encoding the characteristics of the movement of the objects' image across the retina. The other signal, encoding concurrent eye movement characteristics, is usually termed the extraretinal signal, because it does not derive from visual afferents (Matin et al. 1969; Mack 1986; see also Matin 1982;. The comparison mechanism treats the two signals as vectors (see, e.g., Mateeff et al. 1991; Willach et al. 1985) and applies a simple rule: when they differ, object motion is perceived; when they are equal, object stationarity is perceived. Wert...

show abstract

Section: Interfacing Ego-and Object-motion Perception and Visual-vestcontrasting

confidence: 77%

contrasting

confidence: 83%

What does linear vection tell us about the optokinetic pathway?

Sauvan

1994

Behav Brain Sci

View full text Add to dashboard Cite

show abstract

“…This has led to the suggestion (Leibowitz, Post, Brandt, & Dichgans, 1982;Trevarthen, 1968) that visual processing of localization and orientation is under control of an "ambient" system, whereas the processing of fine detail and form is under control of a "focal" system, whose main control is by more central (i.e., foveal and near foveal) pro-cesses, involves perception of fine detail, and is sensitive to the accommodative stimulus. The original suggestions of the ambient/focal distinction proposed a separation of the processing of information related to spatial orientation and localization in superior colliculus from processing of visual form in cortex (Trevarthen, 1968; see also Held, 1968;Ingle, 1967;Schneider, 1967).…”

Section: Adaptation Ofvpel Within Amentioning

confidence: 99%

Light and dark adaptation of visually perceived eye level controlled by visual pitch

Matin

1995

Perception & Psychophysics

View full text Add to dashboard Cite

The pitch of a visual field systematically influences the elevation at which a monocularly viewing subject sets a target so as to appear at visually perceived eye level (VPEL). The deviation of the setting from true eye level averages approximately 0.6 times the angle of pitch while viewing a fully illuminated complexly structured visual field and is only slightly less with one or two pitched-fromvertical lines in a dark field (Matin & Li, 1994a). The deviation of VPEL from baseline following 20 min of dark adaptation reaches its full value less than 1 min after the onset of illumination of the pitched visual field and decays exponentially in darkness following 5 min of exposure to visual pitch, either 30°topbackward or 20°topforward. The magnitude of the VPEL deviation measured with the dark-adapted right eye following left-eye exposure to pitch was 85%ofthe deviation that followed pitch exposure of the right eye itself. Time constants for VPEL decay to the dark baseline were the same for same-eye and cross-adaptation conditions and averaged about 4 min. The time constants for decay during dark adaptation were somewhat smaller, and the change during dark adaptation extended over a 16% smaller range following the viewing of the dim two-line pitched-from-vertical stimulus than following the viewing of the complex field. The temporal course of light and dark adaptation ofVPEL is virtually identical to the course oflight and dark adaptation of the scotopic luminance threshold following exposure to the same luminance. We suggest that, following rod stimulation along particular retinal orientations by portions of the pitched visual field, the storage of the adaptation process resides in the retinogeniculate system and is manifested in the focal system as a change in luminance threshold and in the ambient system as a change in VPEL.The linear model previously developed to account for VPEL, which was based on the interaction of influences from the pitched visual field and extraretinal influences from the body-referenced mechanism, was employed to incorporate the effects of adaptation. Connections between VPEL adaptation and other cases of perceptual adaptation of visual direction are described.The physical elevation of visually perceived eye level (VPEL) changes linearly with the pitch! of an illuminated visual field (Matin & Fox, 1986Matin, Fox, & Doktorsky, 1987;Matin & Li, 1989b, 1992b, 1992c, 1994a, 1994bMatin, Li, & Doktorsky, 1988;Stoper & Cohen, 1989). Employing the normally illuminated and complexly structured pitchroom shown in Figure 1a, average VPEL values for different groups of 8 subjects in two separate experiments deviated from true eye level by 0.61 and 0.63 times the angle of visual pitch over pitch ranges of 65°and 50°, respectively; one of the experiments involved monocular viewing, and the second involved binocular viewing. The slope of each subject's VPEL-versus-pitch function was linear, with individual slopes that ranged from +0.44 to +0.84. These individual slopes have demonstrated a great deal ...

show abstract

“…Visual channels -focal and ambient vision appear to be associated with different resource structures (Leibowitz, Post, Brandt, & Dichgans, 1982;Previc, 1998;Weinstein & Wickens, 1992). For example, it is quite common for people to foveate on a target while processing other peripheral visual stimuli when walking, driving, flying, etc.…”

Section: Multiple Resource Theory (Mrt)mentioning

confidence: 99%