Interpretation of a Discontinuity in the Sense of Verticality at Large Body Tilt

2004 ◽  
Vol 91 (5) ◽  
pp. 2205-2214 ◽  
Author(s):  
Ronald G. Kaptein ◽  
Jan A. M. Van Gisbergen
Keyword(s):  
Spatial Orientation ◽  
Human Subjects ◽  
Large Body ◽  
Body Tilt ◽  
Head Orientation ◽  
Subjective Visual Vertical ◽  
Egocentric Bias ◽  
Visual Vertical ◽  
Series Of Experiments ◽  
Tilt Signal

Results of earlier spatial-orientation studies focusing on the sense of verticality have emphasized an intriguing paradox. Despite evidence that nearly veridical signals for gravicentric head orientation and egocentric visual stimulus orientation are available, roll-tilted subjects err in the direction of the long body axis when adjusting a visual line to vertical in darkness (Aubert effect). This has led to the suggestion that a central egocentric bias signal with fixed strength and direction acts to pull the perceived vertical to the subjects' zenith (M-model). In the present study, the subjective visual vertical (SVV) was tested in six human subjects, across the entire 360° range. For comparison, body-tilt estimates from four subjects where collected in a separate series of experiments. For absolute tilts up to ∼135°, SVV responses showed a gradually increasing Aubert effect that could not be attributed to errors in perceived body tilt but was nicely in line with the M-model. At larger absolute tilts, SVV errors abruptly reversed sign, now showing a pattern concordant with errors in body-tilt estimates but incompatible with the M-model. These results suggest that, in the normal working range, the perception of external space and the perception of body posture are based on different processing of body-tilt signals. Beyond this range, both spatial-orientation tasks seem to rely mainly on a common tilt signal.

Body-Tilt and Visual Verticality Perception During Multiple Cycles of Roll Rotation

2008 ◽  
Vol 99 (5) ◽  
pp. 2264-2280 ◽  
Author(s):  
R.A.A. Vingerhoets ◽  
W. P. Medendorp ◽  
J.A.M. Van Gisbergen
Keyword(s):  
Constant Velocity ◽  
Interaction Model ◽  
The Body ◽  
Body Tilt ◽  
Subjective Visual Vertical ◽  
Egocentric Bias ◽  
Leaky Integrator ◽  
Visual Vertical ◽  
Multiple Cycles ◽  
Roll Tilt

To assess the effects of degrading canal cues for dynamic spatial orientation in human observers, we tested how judgments about visual-line orientation in space (subjective visual vertical task, SVV) and estimates of instantaneous body tilt (subjective body-tilt task, SBT) develop in the course of three cycles of constant-velocity roll rotation. These abilities were tested across the entire tilt range in separate experiments. For comparison, we also obtained SVV data during static roll tilt. We found that as tilt increased, dynamic SVV responses became strongly biased toward the head pole of the body axis (A-effect), as if body tilt was underestimated. However, on entering the range of near-inverse tilts, SVV responses adopted a bimodal pattern, alternating between A-effects (biased toward head-pole) and E-effects (biased toward feet-pole). Apart from an onset effect, this tilt-dependent pattern of systematic SVV errors repeated itself in subsequent rotation cycles with little sign of worsening performance. Static SVV responses were qualitatively similar and consistent with previous reports but showed smaller A-effects. By contrast, dynamic SBT errors were small and unimodal, indicating that errors in visual-verticality estimates were not caused by errors in body-tilt estimation. We discuss these results in terms of predictions from a canal-otolith interaction model extended with a leaky integrator and an egocentric bias mechanism. We conclude that the egocentric-bias mechanism becomes more manifest during constant velocity roll-rotation and that perceptual errors due to incorrect disambiguation of the otolith signal are small despite the decay of canal signals.

scholarly journals Dynamic arm movements attenuate perceptual distortion of visual vertical induced during prolonged whole-body tilt

2020 ◽  
Author(s):  
Keisuke Tani ◽  
Shinji Yamamoto ◽  
Yasushi Kodaka ◽  
Keisuke Kushiro
Keyword(s):  
Central Nervous System ◽  
Arm Movements ◽  
Upright Position ◽  
Body Tilt ◽  
Whole Body ◽  
Subjective Visual Vertical ◽  
Body Movements ◽  
Perceptual Distortion ◽  
Visual Vertical ◽  
The Central Nervous System

AbstractAdditional gravitational cues generated by active body movements may play a role in the perception of gravitational space, but no experimental evidence has been shown on this. To investigate this possibility, we evaluated how arm movements made against gravity influenced the perceptual distortion of visual and postural vertical induced by prolonged whole-body tilt. In Experiment 1, participants were asked to perform static or dynamic arm movements during prolonged whole-body tilt and we assessed their effects on subjective visual vertical (SVV) at the tilt position (during-tilt session) and after tilting back to the upright position (post-tilt session). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that prolonged tilt induced the SVV shifts toward the side of body tilts in both sessions. The prolonged tilt-induced SVV shifts effectively decreased when performing dynamic arm movements in the during-tilt session, but not in the post-tilt session. In Experiment 2, the SPV shifted toward the side of prolonged body tilt, which was not significantly influenced by the performance of static or dynamic arm movements. Results of the during-tilt session suggest that the central nervous system utilizes additional cues generated by dynamic body movements for the perception of the visual vertical.

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.

Evidence for a reference frame transformation of vestibular signal contributions to voluntary reaching

2014 ◽  
Vol 111 (9) ◽  
pp. 1903-1919 ◽  
Author(s):  
Ian Moreau-Debord ◽  
Christophe Z. Martin ◽  
Marianne Landry ◽  
Andrea M. Green
Keyword(s):  
Reference Frame ◽  
Human Subjects ◽  
Vertical Axis ◽  
Vestibular Stimulation ◽  
Body Motion ◽  
Body Tilt ◽  
Head Orientation ◽  
Compensation Mechanisms ◽  
Axis Rotation ◽  
Voluntary Reaching

To contribute appropriately to voluntary reaching during body motion, vestibular signals must be transformed from a head-centered to a body-centered reference frame. We quantitatively investigated the evidence for this transformation during online reach execution by using galvanic vestibular stimulation (GVS) to simulate rotation about a head-fixed, roughly naso-occipital axis as human subjects made planar reaching movements to a remembered location with their head in different orientations. If vestibular signals that contribute to reach execution have been transformed from a head-centered to a body-centered reference frame, the same stimulation should be interpreted as body tilt with the head upright but as vertical-axis rotation with the head inclined forward. Consequently, GVS should perturb reach trajectories in a head-orientation-dependent way. Consistent with this prediction, GVS applied during reach execution induced trajectory deviations that were significantly larger with the head forward compared with upright. Only with the head forward were trajectories consistently deviated in opposite directions for rightward versus leftward simulated rotation, as appropriate to compensate for body vertical-axis rotation. These results demonstrate that vestibular signals contributing to online reach execution have indeed been transformed from a head-centered to a body-centered reference frame. Reach deviation amplitudes were comparable to those predicted for ideal compensation for body rotation using a biomechanical limb model. Finally, by comparing the effects of application of GVS during reach execution versus prior to reach onset we also provide evidence that spatially transformed vestibular signals contribute to at least partially distinct compensation mechanisms for body motion during reach planning versus execution.

Dynamic Effects on the Subjective Visual Vertical After Roll Rotation

2008 ◽  
Vol 100 (2) ◽  
pp. 657-669 ◽  
Author(s):  
Erika N. Lorincz ◽  
Bernhard J. M. Hess
Keyword(s):  
Semicircular Canal ◽  
Constant Velocity ◽  
Human Subjects ◽  
Subjective Visual Vertical ◽  
Dynamic Effects ◽  
Complete Darkness ◽  
Constant Acceleration ◽  
Visual Vertical ◽  
Normal Human ◽  
Roll Tilt

We investigated in normal human subjects how semicircular canal and otolith signals interact in the estimation of the subjective visual vertical after constant velocity or constant acceleration roll tilt. In the constant velocity paradigm, subjects were rotated in darkness at ±60°/s for five complete cycles before being stopped in one of seven orientations ranging from 0 to ±90° (right/left ear down). In the constant acceleration paradigm, subjects were rotated with an acceleration of +30 or −30°/s2 to the same seven end positions between −90 and +90°, by way of passing once through the upside-down position. The subjective visual vertical was assessed by measuring the setting of a luminous line that appeared at different test delays after stop rotation in otherwise complete darkness. The data suggest that gravitational jerk signals generated by otolith–semicircular canal interactions and/or carried by phasic otolith signals are responsible for the observed transient bias in the estimation of the subjective visual vertical. This transient bias depended on both rotation and tilt direction after constant velocity rotations, but was almost abolished following constant acceleration rotations.

Cortical vestibular representation in the superior temporal gyrus

2004 ◽  
Vol 14 (1) ◽  
pp. 33-35
Author(s):  
Stefan Hegemann ◽  
Sabine Fitzek ◽  
Clemens Fitzek ◽  
Michael Fetter
Keyword(s):  
Malignant Melanoma ◽  
Spatial Orientation ◽  
Superior Temporal Gyrus ◽  
Cerebral Metastasis ◽  
Subjective Visual Vertical ◽  
Medial Part ◽  
Unique Case ◽  
Visual Vertical

We present the unique case of a patient with a circumscribed solitary cerebral metastasis of a malignant melanoma extending from the medial part of the superior temporal gyrus to the lower part of the 1st long insular gyrus causing gait and stance instability and an ipsiversive tilt of the subjective visual vertical. Oculomotor disorders could not be detected. We suggest that the superior temporal gyrus is likely to be involved in spatial orientation presumably using otolithic information.

scholarly journals Dynamic arm movements attenuate the perceptual distortion of visual vertical induced during prolonged whole-body tilt

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250851
Author(s):  
Keisuke Tani ◽  
Shinji Yamamoto ◽  
Yasushi Kodaka ◽  
Keisuke Kushiro
Keyword(s):  
Arm Movements ◽  
Body Tilt ◽  
Whole Body ◽  
Subjective Visual Vertical ◽  
Body Movements ◽  
Perceptual Distortion ◽  
Additional Information ◽  
Visual Vertical ◽  
The Central Nervous System ◽  
Spatial Judgment

Concurrent body movements have been shown to enhance the accuracy of spatial judgment, but it remains unclear whether they also contribute to perceptual estimates of gravitational space not involving body movements. To address this, we evaluated the effects of static or dynamic arm movements during prolonged whole-body tilt on the subsequent perceptual estimates of visual or postural vertical. In Experiment 1, participants were asked to continuously perform static or dynamic arm movements during prolonged tilt, and we assessed their effects on the prolonged tilt-induced shifts of subjective visual vertical (SVV) at a tilted position (during-tilt session) or near upright (post-tilt session). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that the SVV was significantly shifted toward the direction of prolonged tilt in both sessions. The SVV shifts decreased when performing dynamic arm movements in the during-tilt session, but not in the post-tilt session. In Experiment 2, as well as SVV, the SPV was shifted toward the direction of prolonged tilt, but it was not significantly attenuated by the performance of static or dynamic arm movements. The results of the during-tilt session suggest that the central nervous system utilizes additional information generated by dynamic body movements for perceptual estimates of visual vertical.

Topology of brainstem lesions associated with subjective visual vertical tilt

Neurology ◽  
2014 ◽  
Vol 82 (22) ◽  
pp. 1968-1975 ◽  
Author(s):  
T.-H. Yang ◽  
S.-Y. Oh ◽  
K. Kwak ◽  
J.-M. Lee ◽  
B.-S. Shin ◽  
...  
Keyword(s):  
Subjective Visual Vertical ◽  
Brainstem Lesions ◽  
Visual Vertical

Cell and Molecular Biological Challenges of ICSI: ART before Science?

1998 ◽  
Vol 26 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Gerald Schatten ◽  
Laura Hewitson ◽  
Calvin Simerly ◽  
Peter Sutovsky ◽  
Gabor Huszar
Keyword(s):  
Rhesus Monkeys ◽  
Nonhuman Primates ◽  
Assisted Reproductive Technologies ◽  
Clinical Investigation ◽  
Human Subjects ◽  
Reproductive Technologies ◽  
Published Data ◽  
New Methods ◽  
Institutional Review ◽  
Series Of Experiments

The general perception of how innovative assisted reproductive technologies (ART) are introduced is through a carefully controlled series of experiments in an animal model, such as the mouse. Only after the technique has been proven can one consider confirmatory studies on mammals closely related to humans, such as rhesus monkeys or other nonhuman primates. With this background of a peer-reviewed body of well-established published data, there is sufficient foundation and rationale to propose a clinical investigation to a responsible human subjects institutional review board (IRB). IRBs weigh the benefits and risks of the new methods to human subjects, and then consider the appropriate informed consent procedures for the particular case. Only after a large number of clinical studies are performed at multiple sites and are peer reviewed can the efficacy and safety of the innovative approach be clearly evaluated. At that time, the potential therapy can be responsibly offered to suitable beneficiaries.

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