Perceived Depth from Dot Density Change by Lateral Head Movements

K Sakurai; H Ono

doi:10.1068/v96p0119

Perceived Depth from Dot Density Change by Lateral Head Movements

Perception ◽

10.1068/v96p0119 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 133-133 ◽

Cited By ~ 1

Author(s):

K Sakurai ◽

H Ono

Keyword(s):

Sine Wave ◽

Visual Input ◽

Head Movements ◽

Trade Off ◽

Rocking Motion ◽

Dot Density ◽

Wave Surfaces ◽

Perceived Motion ◽

Random Dot Pattern ◽

Lateral Head

We investigated whether there is a trade-off between magnitude of perceived depth and that of perceived motion, using density changes (expansion/contraction) in a random-dot pattern yoked to lateral head movements. We simulated sine-wave surfaces with a depth of 0, 1, 2, 4, 8, and 16 cm. Subjects viewed the patterns monocularly while moving their heads from side to side laterally, and reported the magnitude of perceived depth and that of perceived motion. When simulated depth was less than 4 cm, the surfaces looked stationary and the amount of perceived depth was the same as that of simulated depth. When it was more than 4 cm, the surfaces appeared to move in a rocking motion and the amount of perceived depth was smaller than that of simulated depth. The trade-off implies a mechanism which transduces single visual input into depth or motion.

Download Full-text

Characteristics of cervico-ocular responses in the chameleon

Visual Neuroscience ◽

10.1017/s095252380001186x ◽

1997 ◽

Vol 14 (6) ◽

pp. 1175-1184 ◽

Cited By ~ 1

Author(s):

Henri Gioanni ◽

Annie Sansonetti ◽

Mohamed Bennis

Keyword(s):

Low Frequency ◽

Zero Point ◽

Sine Wave ◽

Visual Input ◽

Point Of View ◽

The Body ◽

Head Movements ◽

Frequency Effect ◽

Phase Lag ◽

Saccadic Response

AbstractThe cervico-ocular reflex (COR) was investigated in the chameleon. Two kinds of responses were observed by oscillating the body (sine-wave stimuli) in the fixed-head animal: a "smooth response" of very low gain (around 0.08) and a saccadic response composed of 1–12 saccades per cycle of stimulation (depending on the stimulation frequency). Both responses were elicited in the compensatory direction (same direction as the stimulation) and exhibited a frequency dependence with low-pass properties. The saccadic response was especially developed and displayed a higher gain (up to 0.4) than the smooth response. In darkness, the saccades were triggered near the zero point (head-body alignment), whereas in the presence of a fixed visual surround they were elicited more regularly throughout the stimulation cycle. The amplitude of saccades was increased in the light. Consequently, the gain and the phase lag of the saccadic reponse were enhanced by the visual input. No visuo-cervical interaction was observed for the smooth response. Oscillating the body at a constant velocity (seesaw or ramp stimuli) revealed a frequency effect on the number of saccades (during a cycle of stimulation), but not on the gain of the response. Increasing the amplitude of oscillations augmented only very slightly the amplitude of saccades and consequently decreased the gain. Hence, the best working range of the saccadic response corresponds to body or head movements of low amplitude (up to ±20 deg) and low frequency (up to 0.25 Hz), and is improved by a visual input. These properties are discussed on a comparative point of view. It is proposed that, in chameleons, the saccadic response could contribute to gaze stabilization and add to the vestibulo-ocular and the optokinetic responses.

Download Full-text

Lateral Head Movements as a Sign of Tricuspid Insufficiency

Cardiology ◽

10.1159/000169169 ◽

1967 ◽

Vol 50 (3) ◽

pp. 140-146 ◽

Cited By ~ 1

Author(s):

A.A. Luisada ◽

S. Wissner ◽

P.D. Gupta

Keyword(s):

Head Movements ◽

Tricuspid Insufficiency ◽

Lateral Head

Download Full-text

Motion Parallax Driven by Head Movements: Conditions for Visual Stability, Perceived Depth, and Perceived Concomitant Motion

Perception ◽

10.1068/p5221 ◽

2005 ◽

Vol 34 (4) ◽

pp. 477-490 ◽

Cited By ~ 20

Author(s):

Hiroshi Ono ◽

Hiroyasu Ujike

Keyword(s):

Motion Perception ◽

Depth Perception ◽

Head Movement ◽

Motion Parallax ◽

Head Movements ◽

Visual Stability ◽

Movement Velocity ◽

Motion Threshold ◽

Perceived Motion

Yoking the movement of the stimulus on the screen to the movement of the head, we examined visual stability and depth perception as a function of head-movement velocity and parallax. In experiment 1, for different head velocities, observers adjusted the parallax to find (a) the depth threshold and (b) the concomitant-motion threshold. Between these thresholds, depth was seen with no perceived motion. In experiment 2, for different head velocities, observers adjusted the parallax to produce the same perceived depth. A slower head movement required a greater parallax to produce the same perceived depth as faster head movements. In experiment 3, observers reported the perceived depth for different parallax magnitudes. Perceived depth covaried with smaller parallax without motion perception, but began to decrease with larger parallax and concomitant motion was seen. Only motion was seen with the larger parallax.

Download Full-text

Apparent motion of monocular stimuli in different depth planes with lateral head movements

Vision Research ◽

10.1016/j.visres.2007.01.012 ◽

2007 ◽

Vol 47 (8) ◽

pp. 1027-1035 ◽

Cited By ~ 5

Author(s):

K. Shimono ◽

W.J. Tam ◽

H. Ono

Keyword(s):

Apparent Motion ◽

Head Movements ◽

Lateral Head

Download Full-text

A multivariate clustering approach to display repertoire analysis: headbobbing in Anolis equestris

Amphibia-Reptilia ◽

10.1163/156853889x00476 ◽

1989 ◽

Vol 10 (3) ◽

pp. 331-344 ◽

Cited By ~ 9

Author(s):

Matthew Kramer ◽

Enrique Font

Keyword(s):

Unbiased Estimate ◽

Head Movements ◽

Repertoire Size ◽

Motor Patterns ◽

Repertoire Analysis ◽

Long Duration ◽

Threat Displays ◽

Clustering Approach ◽

Multivariate Clustering ◽

Lateral Head

AbstractDisplay repertoire analysis requires and unbiased estimate of the number of different displays. Anolis lizards, with easily quantifiable visual displays, provide a system amenable to determining display repertoire size. We used multivariate clustering techniques to classify Anolis equastris headbobbing displays. Forty displays, to conspecifics and mirrors, were graphed and 23 variables from each were used in a cluster analysis. Displays were classified into four distinct groups and a single odd display. The most important variables for classifying displays, assessed with a stepwide discriminant analysis, were associated with the general cadence, number of headbobs, and location of large and small headbobs. Most headbobbing displays ended in lateral head movements, possibly arising from ritualized mouth-wiping. All displays analyzed were apparently aggressive ("threat") displays, suggesting a rich display repertoire for this species but leaving unexplained the reasons so many display types are used. Social and defensive displays, while sharing a number of motor patterns, are readily distinguished by the long duration of dewlap extension and gaping in defensive behavior.

Download Full-text

The effect of voluntary head movements on postural kinetics in the standing cat

PeerJ ◽

10.7717/peerj.8186 ◽

2019 ◽

Vol 7 ◽

pp. e8186

Author(s):

Yang Song ◽

Meizi Wang ◽

Julien Steven Baker ◽

Yaodong Gu

Keyword(s):

Kinetic Parameters ◽

Contact Area ◽

Peak Pressure ◽

Head Position ◽

Head Movements ◽

Whole Body ◽

Postural Adjustment ◽

Vestibular Loss ◽

The Right ◽

Lateral Head

Background Although the postural instability accompanying bilateral vestibular loss in human and quadrupeds during lateral head movements are well-known, it is still unclear whether or not lateral head turns would indeed activate the postural control system to maintain balance. This study aimed to examine the kinetic parameters in freely standing intact cats during head movements in order to further answer the above question. Methods Six intact cats were trained to stand, unrestrained on a force plate and perform voluntary head movements to the left and right positions in response to visual cues. Each trial was divided into two phases, quiet standing with the cat’s head maintaining a straight forward and lateral head position after voluntary head movements. Kinetic parameters including peak pressure and contact area under each limb as well as center of pressure (COP) displacements of the whole body were measured. Results Compared to the neutral head position, peak pressure and contact area of the left head position were significantly smaller for the left forelimb while greatly larger for the right forelimb. An exact opposite case of peak pressure and contact area in the forelimbs was found between the right and neutral head positions. In addition, the COP displacements altered oppositely to the head movements, and presented a significantly right shift in the left position and a significantly left shift in the right position. Conclusion These results demonstrate that the lateral displacement of the head in standing intact cats does activate the postural adjustment to maintain balance, which is consistent with the concept that vestibular input can contribute to postural balance during voluntary head turns.

Download Full-text

Controlling motion artefact levels in MR images by suspending data acquisition during periods of head motion

10.1101/230490 ◽

2017 ◽

Author(s):

Rémi Castella ◽

Lionel Arn ◽

Estelle Dupuis ◽

Martina F. Callaghan ◽

Bogdan Draganski ◽

...

Keyword(s):

Data Quality ◽

Data Acquisition ◽

Motion Correction ◽

Head Movements ◽

Head Motion ◽

Motion Artefacts ◽

Motion Artefact ◽

Position Information ◽

Trade Off ◽

Scan Time

AbstractHead movements are a major source of MRI artefacts that hamper radiological assessment and computer-based morphological and functional measures of the human brain. Prospective motion correction techniques continuously update the MRI scanner based on head position information provided by an external tracking system. While prospective motion correction significantly improves data quality, strong motion artefacts may remain with large head motions or when motion takes place at sensitive times of the acquisition. Here we present a framework that allows the suspension of data acquisition when head motion is predicted to have a strong negative impact on data quality. The predictor, calculated in real-time during the acquisition, accounts for the amplitude of the signal acquired at the time of the motion, thereby offering a re-acquisition strategy more efficient than relying on head speed alone. The suspension of data acquisition is governed by the trade-off between image degradation due to motion and prolonging the scan time. This trade-off can be tuned by the user according to the desired level of image quality and the participant‘s tolerability. We test the framework using two motion experiments and two head coils. Significant improvements in data quality are obtained with stringent threshold values for the suspension of acquisition. Substantial reductions in motion artefact levels are also achieved with minimal prolongation of scan time. However, high levels of motion artefacts occasionally remain despite stringent thresholds with the 64-channel head coil, an effect that might be attributed to head movement in the sharp sensitivity profile of this coil.

Download Full-text

Importance of the vestibular system in visually induced nausea and self-vection

Journal of Vestibular Research ◽

10.3233/ves-1999-9202 ◽

1999 ◽

Vol 9 (2) ◽

pp. 83-87 ◽

Cited By ~ 4

Author(s):

Walter H. Johnson ◽

Fred A. Sunahara ◽

Jack P. Landolt

Keyword(s):

Eye Movements ◽

Visual Field ◽

Inner Ear ◽

Vestibular System ◽

Head Movement ◽

Sensory Input ◽

Visual Stimulation ◽

Normal Subjects ◽

Visual Input ◽

Head Movements

The objective of this study was to determine the importance, if any, of the non-auditory labyrinth of the inner ear in visually induced nausea and self-vection in subjects exposed to a moving visual field with and without concomitant pitching head movements. Subjects teated were 15 normals, 18 unilateral labyrinthectomies and 6 bilateral labyrinthectomies. The findings show a higher incidence of pseudo-Coriolis induced nausea in normal subjects compared to unilateral and bilateral labyrinthectomized subjects. When the subjects were exposed to the moving visual field only (no head movement), pronounced self-vection occurred in all subjects, but with earlier onset in the bilateral labyrinthine defective subjects as compared to normal and unilateral defective subjects. The subjective intensities of self-vections reported by labyrinth-defectives were much more pronounced as compared to normal subjects, and it is apparent that visual input in these subjects achieves much more importance in maintaining compensatory eye movements, and the gain of neck reflexes is enhanced. The findings that visual stimulation is more effective in producing the disabling effects after labyrinthine destruction could possibly be explained by enhancement of vision after loss of labyrinthine sensory input, and the gain in neck reflexes is also enhanced after labyrinthectomy.

Download Full-text