Egocentric and allocentric alignment tasks are affected by otolith input

2012 ◽  
Vol 107 (11) ◽  
pp. 3095-3106 ◽  
Author(s):  
Alexander A. Tarnutzer ◽  
Christopher J. Bockisch ◽  
Itsaso Olasagasti ◽  
Dominik Straumann
Keyword(s):  
Reference Frame ◽  
Longitudinal Axis ◽  
Line Orientation ◽  
Roll Angle ◽  
Frames Of Reference ◽  
Gravity Vector ◽  
Ocular Torsion ◽  
Luminous Line ◽  
Precision And Accuracy ◽  
Head Roll

Gravicentric visual alignments become less precise when the head is roll-tilted relative to gravity, which is most likely due to decreasing otolith sensitivity. To align a luminous line with the perceived gravity vector (gravicentric task) or the perceived body-longitudinal axis (egocentric task), the roll orientation of the line on the retina and the torsional position of the eyes relative to the head must be integrated to obtain the line orientation relative to the head. Whether otolith input contributes to egocentric tasks and whether the modulation of variability is restricted to vision-dependent paradigms is unknown. In nine subjects we compared precision and accuracy of gravicentric and egocentric alignments in various roll positions (upright, 45°, and 75° right-ear down) using a luminous line (visual paradigm) in darkness. Trial-to-trial variability doubled for both egocentric and gravicentric alignments when roll-tilted. Two mechanisms might explain the roll-angle–dependent modulation in egocentric tasks: 1) Modulating variability in estimated ocular torsion, which reflects the roll-dependent precision of otolith signals, affects the precision of estimating the line orientation relative to the head; this hypothesis predicts that variability modulation is restricted to vision-dependent alignments. 2) Estimated body-longitudinal reflects the roll-dependent variability of perceived earth-vertical. Gravicentric cues are thereby integrated regardless of the task's reference frame. To test the two hypotheses the visual paradigm was repeated using a rod instead (haptic paradigm). As with the visual paradigm, precision significantly decreased with increasing head roll for both tasks. These findings propose that the CNS integrates input coded in a gravicentric frame to solve egocentric tasks. In analogy to gravicentric tasks, where trial-to-trial variability is mainly influenced by the properties of the otolith afferents, egocentric tasks may also integrate otolith input. Such a shared mechanism for both paradigms and frames of reference is supported by the significantly correlated trial-to-trial variabilities.

Roll-Dependent Modulation of the Subjective Visual Vertical: Contributions of Head- and Trunk-Based Signals

2010 ◽  
Vol 103 (2) ◽  
pp. 934-941 ◽  
Author(s):  
A. A. Tarnutzer ◽  
C. J. Bockisch ◽  
D. Straumann
Keyword(s):  
Reference Frame ◽  
Sensory Input ◽  
Reference Frames ◽  
Longitudinal Axis ◽  
Subjective Visual Vertical ◽  
Lateral Tilt ◽  
Accuracy And Precision ◽  
Visual Vertical ◽  
Fixed Reference ◽  
Precision And Accuracy

Precision and accuracy of the subjective visual vertical (SVV) modulate in the roll plane. At large roll angles, systematic SVV errors are biased toward the subject's body-longitudinal axis and SVV precision is decreased. To explain this, SVV models typically implement a bias signal, or a prior, in a head-fixed reference frame and assume the sensory input to be optimally tuned along the head-longitudinal axis. We tested the pattern of SVV adjustments both in terms of accuracy and precision in experiments in which the head and the trunk reference frames were not aligned. Twelve subjects were placed on a turntable with the head rolled about 28° counterclockwise relative to the trunk by lateral tilt of the neck to dissociate the orientation of head- and trunk-fixed sensors relative to gravity. Subjects were brought to various positions (roll of head- or trunk-longitudinal axis relative to gravity: 0°, ±75°) and aligned an arrow with perceived vertical. Both accuracy and precision of the SVV were significantly ( P < 0.05) better when the head-longitudinal axis was aligned with gravity. Comparing absolute SVV errors for clockwise and counterclockwise roll tilts, statistical analysis yielded no significant differences ( P > 0.05) when referenced relative to head upright, but differed significantly ( P < 0.001) when referenced relative to trunk upright. These findings indicate that the bias signal, which drives the SVV toward the subject's body-longitudinal axis, operates in a head-fixed reference frame. Further analysis of SVV precision supports the hypothesis that head-based graviceptive signals provide the predominant input for internal estimates of visual vertical.

Frames of reference in discourse: Spatial descriptions in Bashkir (Turkic)

2018 ◽  
Vol 29 (3) ◽  
pp. 495-544
Author(s):  
Tatiana Nikitina
Keyword(s):  
Spatial Cognition ◽  
Reference Frame ◽  
Frames Of Reference ◽  
Linguistic Relativity ◽  
Matching Task ◽  
Spatial Reference ◽  
Lexical Choice ◽  
Linguistic Strategies ◽  
Coding Strategies ◽  
Growing Body

AbstractIn spite of the growing body of research on frames of spatial reference, a number of important questions remain unanswered. This study explores reference frame use in Bashkir, based on a linguistic matching task and a nonverbal task. In the linguistic task, speakers relied freely on intrinsic and relative frames. In intrinsic descriptions, two different kinds of mapping were attested: a mapping based on the Ground’s function, and a mapping based on the Ground’s shape. Several factors were identified that affect the choice of linguistic description, including lexical choice, the chair’s orientation with respect to the viewer, and the speaker’s age. Interference from Russian was not a significant factor. The repair strategies speakers used when encountering misunderstanding suggest that they were not aware of the source of their difficulties. A number of previous studies reported, for different languages, a correlation between reference frame use in linguistic and nonlinguistic tasks, supporting the linguistic relativity hypothesis. The data from Bashkir shows no such correlation: nonverbal coding strategies did not correspond to the same individual’s linguistic strategies, but correlated with the use of Russian in linguistic descriptions. I interpret this finding tentatively as pointing toward a mediated relationship between spatial cognition and language.

Evidence for a retinal velocity memory underlying the direction of anticipatory smooth pursuit eye movements

2013 ◽  
Vol 110 (3) ◽  
pp. 732-747 ◽  
Author(s):  
T. Scott Murdison ◽  
Chanel A. Paré-Bingley ◽  
Gunnar Blohm
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Velocity ◽  
Smooth Pursuit Eye Movements ◽  
Ocular Torsion ◽  
Pursuit Eye Movements ◽  
Ocular Counterroll ◽  
In Series ◽  
Head Roll ◽  
Directional Component

To compute spatially correct smooth pursuit eye movements, the brain uses both retinal motion and extraretinal signals about the eyes and head in space ( Blohm and Lefèvre 2010 ). However, when smooth eye movements rely solely on memorized target velocity, such as during anticipatory pursuit, it is unknown if this velocity memory also accounts for extraretinal information, such as head roll and ocular torsion. To answer this question, we used a novel behavioral updating paradigm in which participants pursued a repetitive, spatially constant fixation-gap-ramp stimulus in series of five trials. During the first four trials, participants' heads were rolled toward one shoulder, inducing ocular counterroll (OCR). With each repetition, participants increased their anticipatory pursuit gain, indicating a robust encoding of velocity memory. On the fifth trial, they rolled their heads to the opposite shoulder before pursuit, also inducing changes in ocular torsion. Consequently, for spatially accurate anticipatory pursuit, the velocity memory had to be updated across changes in head roll and ocular torsion. We tested how the velocity memory accounted for head roll and OCR by observing the effects of changes to these signals on anticipatory trajectories of the memory decoding (fifth) trials. We found that anticipatory pursuit was updated for changes in head roll; however, we observed no evidence of compensation for OCR, representing the absence of ocular torsion signals within the velocity memory. This indicated that the directional component of the memory must be coded retinally and updated to account for changes in head roll, but not OCR.

Frames of Reference for Hand Orientation

1995 ◽  
Vol 7 (2) ◽  
pp. 182-195 ◽  
Author(s):  
Martha Flanders ◽  
John F. Soechting
Keyword(s):  
Reference Frame ◽  
Neural Control ◽  
Human Subjects ◽  
Object Orientation ◽  
Frame Of Reference ◽  
Object Location ◽  
Frames Of Reference ◽  
Spatial Reference ◽  
Hand Orientation ◽  
Spatial Reference Frame

In reaching and grasping movements, information about object location and object orientation is used to specify the appropriate proximal arm posture and the appropriate positions for the wrist and fingers. Since object orientation is ideally defined in a frame of reference fixed in space, this study tested whether the neural control of hand orientation is also best described as being in this spatial reference frame. With the proximal arm in various postures, human subjects used a handheld rod to approximate verbally defined spatial orientations. Subjects did quite well at indicating spatial vertical and spatial horizontal but made consistent errors in estimating 45° spatial slants. The errors were related to the proximal arm posture in a way that indicated that oblique hand orientations may be specified as a compromise between a reference frame fixed in space and a reference frame fixed to the arm. In another experiment, where subjects were explicitly requested to use a reference frame fixed to the arm, the performance was consistently biased toward a spatial reference frame. The results suggest that reaching and grasping movements may be implemented as an amalgam of two frames of reference, both neurally and behaviorally.

scholarly journals On the relation between ocular torsion and visual perception of line orientation

2008 ◽  
Vol 48 (13) ◽  
pp. 1488-1496 ◽  
Author(s):  
Samanthi C. Goonetilleke ◽  
Laura E. Mezey ◽  
Ann M. Burgess ◽  
Ian S. Curthoys
Keyword(s):  
Visual Perception ◽  
Line Orientation ◽  
Ocular Torsion

scholarly journals Radial basis function neural network for head roll prediction modelling in a motion sickness study

2019 ◽  
Vol 15 (3) ◽  
pp. 1637 ◽  
Author(s):  
Sarah ‘Atifah Saruchi ◽  
Mohd Hatta Mohammed Ariff ◽  
Mohd Ibrahim Shapiai ◽  
Nurhaffizah Hassan ◽  
Nurbaiti Wahid ◽  
...  
Keyword(s):  
Neural Network ◽  
Prediction Model ◽  
Radial Basis Function ◽  
Motion Sickness ◽  
Basis Function ◽  
Roll Angle ◽  
Lateral Acceleration ◽  
Subjective Vertical ◽  
Radial Basis ◽  
Head Roll

<span>Motion Sickness (MS) is the result of uneasy feelings that occurs when travelling. In MS mitigation studies, it is necessary to investigate and measure the occupant’s Motion Sickness Incidence (MSI) for analysis purposes. One way to mathematically calculate the MSI is by using a 6-DOF Subjective Vertical Conflict (SVC) model. This model utilises the information of the vehicle lateral acceleration and the occupant’s head roll angle to determine the MSI. The data of the lateral acceleration can be obtained by using a sensor. However, it is impractical to use a sensor to acquire the occupant’s head roll response. Therefore, this study presents the occupant’s head roll prediction model by using the Radial Basis Function Neural Network (RBFNN) method to estimate the actual head roll responses. The prediction model is modelled based on the correlation between lateral acceleration and head roll angle during curve driving. Experiments have been conducted to collect real naturalistic data for modelling purposes. The results show that the predicted responses from the model are similar with the real responses from the experiment. In future, it is expected that the prediction model will be useful in measuring the occupant’s MSI level by providing the estimated head roll responses.</span>

Prediction of the Spatial Orientation of a Ship by Means of Neural Networks

2013 ◽  
Vol 210 ◽  
pp. 223-233
Author(s):  
Tomasz Praczyk ◽  
Piotr Szymak
Keyword(s):  
Neural Networks ◽  
Control System ◽  
Reference Frame ◽  
Spatial Orientation ◽  
Roll Angle ◽  
Higher Harmonic ◽  
Harmonic Components

When designing a control system for a ship gun, the problem is to predict orientation of the ship in an assumed reference frame. This problem can be solved with different regression tools out of which one are neural networks. To verify their abilities to predict spatial orientation of a ship, experiments were carried out. In the experiments, the task of neural networks was to predict the roll angle which changed according to seven model sinusoid functions with different parameters and higher harmonic components.

Ocular Counterroll Modulates the Preferred Direction of Saccade-Related Pontine Burst Neurons in the Monkey

2001 ◽  
Vol 86 (2) ◽  
pp. 935-949 ◽  
Author(s):  
Hansjörg Scherberger ◽  
Jan-Harry Cabungcal ◽  
Klaus Hepp ◽  
Yasuo Suzuki ◽  
Dominik Straumann ◽  
...  
Keyword(s):  
Eye Movements ◽  
Reference Frame ◽  
Vertical Plane ◽  
Motor Command ◽  
Velocity Signal ◽  
Burst Neurons ◽  
Preferred Direction ◽  
Ocular Counterroll ◽  
Head Roll ◽  
Static Head

Saccade-related burst neurons in the paramedian pontine reticular formation (PPRF) of the head-restrained monkey provide a phasic velocity signal to extraocular motoneurons for the generation of rapid eye movements. In the superior colliculus (SC), which directly projects to the PPRF, the motor command for conjugate saccades with the head restrained in a roll position is represented in a reference frame in between oculocentric and space-fixed coordinates with a clear bias toward gravity. Here we studied the preferred direction of premotor burst neurons in the PPRF during static head roll to characterize their frame of reference with respect to head and eye position. In 59 neurons (short-lead, burst-tonic, and long-lead burst neurons), we found that the preferred direction of eye displacement of these neurons changed, relative to head-fixed landmarks, in the horizontal-vertical plane during static head roll. For the short-lead burst neurons and the burst-tonic group, the change was about one-fourth of the amount of ocular counterroll (OCR) and significantly different from a head-centered representation. In the long-lead burst neurons, the rotation of the preferred direction showed a larger trend of about one-half of OCR. During microelectrical stimulation of the PPRF (9 sites in 2 monkeys), the elicited eye movements rotated with about one-half the amount of OCR. In a simple pulley model of the oculomotor plant, the noncraniocentric reference frame of the PPRF output neurons could be reproduced for recently measured pulley positions, if the pulleys were assumed to rotate as a function of OCR with a gain of 0.5. We conclude that the saccadic displacement signal is transformed from a representation in the SC with a clear bias to gravity to a representation in the PPRF that is closely craniocentric, but rotates with OCR, consistent with current concepts of the oculomotor plant.

scholarly journals ETHER AND EQUIVALENCE OF INERTIAL FRAMES OF REFERENCE

2020 ◽  
Vol 6 (7) ◽  
pp. 156-166
Author(s):  
Andrew Chubykalo ◽  
Augusto Espinoza ◽  
Victor Kuligin ◽  
Maria Korneva
Keyword(s):  
Reference Frame ◽  
Experimental Research ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Frames Of Reference ◽  
Inertial Reference Frame ◽  
Inertial Frames ◽  
Action At A Distance

The paper discusses the problem of equality of Inertial frames of reference IFR. The hypothesis of a physical ether, whose properties do not depend on the choice of an inertial reference frame, is proposed. Based on the concept of the physical ether, it turns out the features of instantaneous action at a distance. It is shown that there is a class of transformations that preserves Maxwell’s equations unchanged. The problem of choosing a transformation is posed. This choice should be based on experimental research.

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