Effect of forward head inclination on visual orientation during lateral body tilt.

1972 ◽  
Vol 96 (1) ◽  
pp. 203-205 ◽  
Author(s):  
N. J. Wade
Keyword(s):  
Body Tilt ◽  
Visual Orientation ◽  
Lateral Body

Perception of the Visual Horizontal during Lateral Body Tilt: Right-Left Asymmetries

1978 ◽  
Vol 47 (3) ◽  
pp. 715-720 ◽  
Author(s):  
Martin Bauermeister
Keyword(s):  
Body Tilt ◽  
Linear Effect ◽  
Non Linear Effect ◽  
Lateral Body ◽  
Non Linear ◽  
The Right

Subjects, 55 males and 45 females, indicated by means of a luminescent rod the visual horizontal under conditions of lateral body tilt ranging from 10° to 90° to the right and to the left. There was a non-linear effect of the angle of tilt on the degree of deviation of apparent from objective horizontal. With small angles of tilt the apparent horizontal tended to deviate opposite to the direction of body tilt, with larger angles, in the direction of tilt. Uncertainty of judgment increased with increasing angles of tilt.

Perceived Body Position under Lateral Body Tilt

1969 ◽  
Author(s):  
A. Harvey Baker ◽  
Leonard Cirillo ◽  
Seymour Wapner
Keyword(s):  
Body Position ◽  
Body Tilt ◽  
Lateral Body

Method of Stimulus Presentation and Apparent Body Position under Lateral Body Tilt

1967 ◽  
Vol 24 (1) ◽  
pp. 43-50 ◽  
Author(s):  
M. Bauermeister ◽  
S. Wapner ◽  
H. Werner
Keyword(s):  
Reference System ◽  
Body Position ◽  
Body Schema ◽  
Stimulus Presentation ◽  
Body Axis ◽  
Body Tilt ◽  
Spatial Reference ◽  
Longitudinal Body Axis ◽  
Lateral Body ◽  
Method Of Constant Stimuli

Eighty Ss, 40 male and 40 female, indicated by means of a luminescent rod the location of their longitudinal body axis (apparent body position) under body tilt ranging from 90° left (counterclockwise), through upright, to 90° right (clockwise). The luminescent rod was presented by two psychophysical methods: (a) the method of limits and (b) the method of constant stimuli. Deviations of apparent from objective body position showed significant differences between the two methods. The results were interpreted in terms of an organismic theory of perception, utilizing the notion of a dynamic body schema as spatial reference system which was subject to modifications due to the method of stimulus presentation.

Nature of the Transition Between Two Modes of External Space Perception in Tilted Subjects

2005 ◽  
Vol 93 (6) ◽  
pp. 3356-3369 ◽  
Author(s):  
Ronald G. Kaptein ◽  
Jan A. M. Van Gisbergen
Keyword(s):  
Opposite Sign ◽  
Human Subjects ◽  
Space Perception ◽  
Body Tilt ◽  
Repeated Testing ◽  
Subjective Vertical ◽  
Inverted Position ◽  
Lateral Body ◽  
Visual Vertical ◽  
Response Modes

A striking feature of visual verticality estimates in the dark is undercompensation for lateral body tilt. Earlier studies and models suggest that this so-called Aubert (A) effect increases gradually to around 130° tilt and then decays smoothly on approaching the inverted position. By contrast, we recently found an abrupt transition toward errors of opposite sign (E effect) when body tilt exceeded 135°. The present study was undertaken to clarify the nature of this transition. We tested the subjective visual vertical in stationary roll-tilted human subjects using various rotation paradigms and testing methods. Cluster analysis identified two clearly separate response modes (A or E effect), present in all conditions, which dominated in different but overlapping tilt ranges. Within the overlap zone, the subjective vertical appeared bistable on repeated testing with responses in both categories. The tilt range where bistability occurred depended on the direction of the preceding rotation (hysteresis). The overlap zone shifted to a smaller tilt angle when testing was preceded by a rotation through the inverted position, compared with short opposite rotations from upright. We discuss the possibility that the A-E transition reflects a reference shift from compensating line settings for the head deviation from upright to basing them on the tilt deviation of the feet from upright. In this scenario, both the A and the E effect reflect tilt undercompensation. To explain the hysteresis and the bistability, we propose that the transition is triggered when perceived body tilt, a signal with known noise and hysteresis properties, crosses a fixed threshold.

Lateropulsion After Hemispheric Stroke: A Form of Spatial Neglect Involving Graviception

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000011826
Author(s):  
Shenhao Dai ◽  
Céline Piscicelli ◽  
Emmanuelle Clarac ◽  
Monica Baciu ◽  
Marc Hommel ◽  
...  
Keyword(s):  
The Body ◽  
Spatial Neglect ◽  
Body Orientation ◽  
Body Tilt ◽  
Vertical Orientation ◽  
Lateral Body ◽  
Pusher Syndrome ◽  
Visual Vertical ◽  
Straight Ahead ◽  
Cardinal Sign

ObjectiveTo test the hypothesis that lateropulsion is an entity expressing an impaired body orientation with respect to gravity, in relation to a biased graviception and spatial neglect.MethodsData from the DOBRAS cohort (ClinicalTrials.gov:NCT03203109), were collected 30 days after a first hemisphere stroke. Lateral body tilt, pushing and resistance were assessed with the Scale for Contraversive Pushing.ResultsAmong 220 individuals, 72% were Upright and 28% showed lateropulsion (Tilters=14% less severe than Pushers=14%). The three signs had very high factor loadings (>0.90) on a same dimension, demonstrating that lateropulsion was effectively an entity comprising body tilt (cardinal sign), pushing and resistance. The factorial analyses also showed that lateropulsion was inseparable from the visual vertical (VV), a criterion referring to vertical orientation (graviception). Contralesional VV biases were frequent (44%), with a magnitude related to lateropulsion severity: Upright -0.6°(-2.9;2.4), Tilters -2.9°(-7;0.8), Pushers -12.3°(-15.4;-8.5). Ipsilesional VV biases were less frequent and milder (p<0.001). They did not deal with graviception, 84% being found in upright individuals. Multivariate, factorial, contingency, and prediction analyses congruently showed strong similarities between lateropulsion and spatial neglect, the latter encompassing the former.ConclusionsLateropulsion (pusher syndrome) is a trinity constituted by body tilt, pushing and resistance. It is a way to adjust the body orientation in the roll plane to a wrong reference of verticality. Referring to straight above, lateropulsion might correspond to a form of spatial neglect (referring to straight ahead), which would advocate for 3-D maps in the human brain involving the internal model of verticality.

Perception of Orientation: Adaptation to Lateral Body-Tilt

1966 ◽  
Vol 79 (2) ◽  
pp. 265 ◽  
Author(s):  
Joseph H. McFarland ◽  
Frank Clarkson
Keyword(s):  
Body Tilt ◽  
Lateral Body

Effect of Prolonged Tilt on Visual Orientation

1970 ◽  
Vol 22 (3) ◽  
pp. 423-439 ◽  
Author(s):  
N. J. Wade
Keyword(s):  
Strong Support ◽  
Head Tilt ◽  
Body Tilt ◽  
Visual Orientation ◽  
Lateral Tilt ◽  
Relative Contribution ◽  
Trunk Tilt ◽  
Otolith System

Visual orientation during lateral tilt is viewed in terms of orientation constancy. The postural systems involved in the maintenance of constancy are considered to be those of the otolith, neck and trunk. The relative contribution of these systems was investigated by obtaining visual verticality judgments immediately upon and several minutes after head, body, and trunk tilts. Due to the apparent non-adaptation of the otolith system any changes in visual orientation resulting from prolonged tilt would be attributed to adaptation of the proprioceptive system stimulated. For 30° head tilt visual orientation over-constancy was reduced by about 2°, reflecting the influence of the neck system. Prolonged body tilts of 30°, 60° and 90° reduced the constancy operating by approximately 1°, 3° and 8°, respectively. This was taken to indicate the contribution of the trunk system, which increased with increasing degrees of body tilt. The above interpretations received strong support from experiments involving trunk tilt, which stimulates only the neck and trunk systems.

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