scholarly journals Paradoxical stabilization of relative position in moving frames

2021 ◽  
Vol 118 (25) ◽  
pp. e2102167118
Author(s):  
Mert Özkan ◽  
Stuart Anstis ◽  
Bernard M. ’t Hart ◽  
Mark Wexler ◽  
Patrick Cavanagh
Keyword(s):  
Frame Of Reference ◽  
Moving Frame ◽  
Moving Frames ◽  
Visual Stability ◽  
Left Edge ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Object Relative ◽  
As If

To capture where things are and what they are doing, the visual system may extract the position and motion of each object relative to its surrounding frame of reference [K. Duncker, Routledge and Kegan Paul, London 161–172 (1929) and G. Johansson, Acta Psychol (Amst.) 7, 25–79 (1950)]. Here we report a particularly powerful example where a paradoxical stabilization is produced by a moving frame. We first take a frame that moves left and right and we flash its right edge before, and its left edge after, the frame’s motion. For all frame displacements tested, the two edges are perceived as stabilized, with the left edge on the left and right edge on the right, separated by the frame’s width as if the frame were not moving. This stabilization is paradoxical because the motion of the frame itself remains visible, albeit much reduced. A second experiment demonstrated that unlike other motion-induced position shifts (e.g., flash lag, flash grab, flash drag, or Fröhlich), the illusory shift here is independent of speed and is set instead by the distance of the frame’s travel. In this experiment, two probes are flashed inside the frame at the same physical location before and after the frame moves. Despite being physically superimposed, the probes are perceived widely separated, again as if they were seen in the frame’s coordinates and the frame were stationary. This paradoxical stabilization suggests a link to visual stability across eye movements where the displacement of the entire visual scene may act as a frame to stabilize the perception of relative locations.

scholarly journals Paradoxical stabilization of relative position in moving frames

2021 ◽  
Author(s):  
Mert Özkan ◽  
Stuart Anstis ◽  
Bernard M. ’t Hart ◽  
Mark Wexler ◽  
Patrick Cavanagh
Keyword(s):  
Eye Movements ◽  
Frame Of Reference ◽  
Moving Frame ◽  
Moving Frames ◽  
Left Edge ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Object Relative ◽  
As If

ABSTRACTTo capture where things are and what they are doing, the visual system may extract the position and motion of each object relative to its surrounding frame of referencee.g., 1,2. Here we report a particularly powerful example where a paradoxical stabilization is produced by a moving frame. We first take a frame that moves left and right and we flash its right edge before, and its left edge after, the frame’s motion. For all frame displacements tested, the two edges are perceived as stabilized, with the left edge on the left and right edge on the right, separated by the frame’s width as if the frame were not moving. This illusory stabilization holds even when the frame travels farther than its width, reversing the actual spatial order of the two flashes. Despite this stabilization, the motion of the frame is still seen, albeit much reduced, and this hides the paradoxical standstill of relative positions. In a second experiment, two probes are flashed inside the frame at the same physical location before and after the frame moves. Despite being physically superimposed, the probes are perceived widely separated, again as if they were seen in the frame’s coordinates and the frame were stationary. This illusory separation is set by the distance of the frame’s travel, independently of its speed. This paradoxical stabilization suggests a link to visual constancy across eye movements where the displacement of the entire visual scene may act as a frame to stabilize the perception of relative locations.

scholarly journals Effect of dental wear, stabilization appliance and anterior tooth reconstruction on mandibular movements during speech

2008 ◽  
Vol 19 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Priscila de Oliveira Serrano ◽  
Fernanda Faot ◽  
Altair Antoninha Del Bel Cury ◽  
Renata Cunha Matheus Rodrigues Garcia
Keyword(s):  
Tooth Wear ◽  
Anterior Tooth ◽  
Control Group ◽  
Dental Wear ◽  
Jaw Opening ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Tracking Device ◽  
Mandibular Movements

This study described changes in mandibular movements during pronunciation of /m/ and /s/ sounds in Portuguese, in patients presenting dental wear before and after appliance insertion and tooth reconstruction. Subjects were divided into a control group of dentate patients and an experimental group of patients with incisal tooth wear due to bruxism. A magnetic jaw tracking device measured the jaw opening, and translations to left and right sides of the mandible during pronunciation of phonemes. Evaluations were carried out 1 week and immediately before appliance insertion; 24 h, 7, 30 and 60 days after appliance insertion; and 1 week and 1 month after tooth reconstruction. Data were submitted to two-way ANOVA, Mann-Whitney and Friedman tests (p<0.05). Jaw opening was different (p<0.05) for both sounds in all periods. The anteroposterior amplitude for /s/ showed differences immediately before and 1 month after appliance insertion (p<0.05). Lateral amplitude for the right side showed differences between groups after appliance insertion for /s/, and 1 and 2 months after appliance insertion for the /m/ (p<0.05). Volunteers with anterior tooth wear had a wider opening movement, and the movements during speech of /m/ and /s/ sounds were not changed after appliance insertion and reconstruction of teeth.

scholarly journals Hemispheric Lateralization of Pain Processing by Amygdala Neurons

2009 ◽  
Vol 102 (4) ◽  
pp. 2253-2264 ◽  
Author(s):  
Guangchen Ji ◽  
Volker Neugebauer
Keyword(s):  
Receptive Fields ◽  
Hemispheric Lateralization ◽  
Central Nucleus ◽  
Recording Site ◽  
Peripheral Tissues ◽  
Arthritis Induction ◽  
Before And After ◽  
Pain State ◽  
Left And Right ◽  
The Right

Recent biochemical and behavioral data suggest right-hemispheric lateralization of amygdala functions in pain. Our previous electrophysiological studies showed pain-related neuroplasticity in the latero-capsular division of the central nucleus of the amygdala (CeLC) in the right brain hemisphere. Here we determined differences in the processing of pain-related signals in right versus left CeLC neurons. Individual CeLC neurons were recorded extracellularly before and after induction of an arthritis pain state in anesthetized rats. Brief innocuous and noxious test stimuli were applied to peripheral tissues ipsi- and contralateral to the recording site. A monoarthritis was induced in the ipsi- or contralateral knee by intraarticular injections of kaolin and carrageenan. Under normal conditions, CeLC neurons in the left amygdala had smaller receptive fields than those in the right, but the magnitude of background and evoked activity was not significantly different. After arthritis induction, neurons in the right, but not left, CeLC developed increased background activity and evoked responses, irrespective of the location of the arthritis (ipsi- or contralateral to the recording site). A protein kinase A (PKA) inhibitor decreased the activity of right CeLC neurons after arthritis induction but had no effect in the left amygdala. Forskolin, however, increased the activity of left and right CeLC neurons under normal conditions. The results show for the first time laterality of pain-related electrophysiological activity changes in individual amygdala neurons. Whereas both left and right amygdala neurons receive nociceptive inputs and can become sensitized in principle, a yet unknown mechanism prevents PKA activation and pain-related changes in the left amygdala.

scholarly journals Observations of a Severe, Left-Moving Supercell on 4 May 2003

2005 ◽  
Vol 20 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Daniel T. Lindsey ◽  
Matthew J. Bunkers
Keyword(s):  
Rapid Motion ◽  
Before And After ◽  
Merging Process ◽  
Left And Right ◽  
The Right

Abstract A case study of a left-moving supercell with a rapid motion is presented to (i) elucidate differences in anvil orientations between left- and right-moving supercells and (ii) highlight the interaction of the left mover with a tornadic right mover. It is shown how anvil orientations, as viewed from satellite, may be used to assist in the identification of thunderstorms with differing motions and how this applies to splitting supercells. Additionally, the movement of the left mover into the forward flank of the right mover may have temporarily affected its tornadic circulation, as tornadoes occurred both before and after the merger, despite the structure of the right mover being interrupted during the merging process. Given the dearth of literature on thunderstorm mergers in general, and how mergers affect tornadic supercells in particular, this is an area that demands further research.

Effects of Acupuncture and An Agonist of Opiate Receptors on Heroin Dependent Patients

1999 ◽  
Vol 27 (02) ◽  
pp. 143-148 ◽  
Author(s):  
M. F. Timofeev
Keyword(s):  
Opiate Receptors ◽  
Acupuncture Points ◽  
Interhemisphere Asymmetry ◽  
Drug Addicts ◽  
Treatment Results ◽  
Before And After ◽  
Left And Right ◽  
Group 2 ◽  
The Right ◽  
Group 1

This study examined the influence of acupuncture and an agonist of opiate receptors (Procedol) by means of temperature in both the left and right auricular "Lung" points, and on the coefficIent of interhemisphere asymmetry. Twenty heroin dependent patients participated in this research. They were evenly divided into two groups. Both groups consisted of 10 male drug addicts (18-19 years old) who had been using heroin for 8-10 months. Group 1 received 1.0 ml procedol (i. m.). Group 2 were treated with acupuncture. Temperature was measured on the acupuncture points before and after treatment. Results of this study showed that temperature increased on the left and decreased on the right acupuncture points in both the procedol and acupuncture treated groups. The net changes before and after treatment were 92.87% and 92.53% in groups 1 and 2 respectively. The therapeutic effect of acupuncture on treatment of heroin dependence is through the same pathway as the agonist on opiate receptors, 20% of patients are resisted to acupuncture.

Forced Single-Nostril Breathing and Cognition

1994 ◽  
Vol 79 (3_suppl) ◽  
pp. 1499-1506 ◽  
Author(s):  
Barbara Sanders ◽  
Clairessa Lattimore ◽  
Kirsten Smith ◽  
Lisa Dierker
Keyword(s):  
Phase Ii ◽  
Cognitive Abilities ◽  
Cognitive Testing ◽  
Left Nostril ◽  
Breathing Exercise ◽  
Matching Test ◽  
Before And After ◽  
Left And Right ◽  
Forced Breathing ◽  
The Right

This experiment investigated whether forced single-nostril breathing differentially affects cognitive abilities presumed to be mediated by the left and right cerebral hemispheres. Phase I was an attempted replication of a reported sex difference in the effects of unilateral breathing on verbal versus spatial performance and Phase II was a study of breathing effects on different verbal and spatial tests. No differences associated with breathing condition were found in the replication study. In Phase II, men breathing through the right nostril scored significantly lower than men in the control condition on a letter-matching test although they did not differ significantly from men in the left-nostril condition on that test. There were no significant breathing-related differences on two spatial tests, and no differences associated with breathing condition for the women. Assessment of nostril dominance before and after cognitive testing showed that the forced-breathing exercise did not significantly alter subjects' nostril dominance. A significant left-nostril bias was found in this sample.

Effect of PSSE on postural sway in AIS using center of pressure

2021 ◽  
Author(s):  
M Selthafner ◽  
XC Liu ◽  
F Ellis ◽  
C Tassone ◽  
J Thometz ◽  
...  
Keyword(s):  
Postural Sway ◽  
Center Of Pressure ◽  
Physical Therapist ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Peak Pressures ◽  
Anterior Posterior

We haven’t known whether the center of pressure (COP) could be considered as a better indicator in the evaluation of posture and balance change after the physiotherapeutic scoliosis specific exercise (PSSE) during level walking. The objective of this study was: 1) to determine changes in COP displacement in anterior-posterior (COP-AP) and medial-lateral (COP-ML) for AIS following the PSSE; 2) to find out COP oscillation(COP-OS) from the midline for the left and right foot; 3) to investigate max pressure at the forefoot, midfoot and hindfoot bilaterally. AIS patients with three reflective markers on their back walked on the pressure sensors embedded treadmill at 2 km/h and their trunks were also registered by DIERS Formetric 4D system. Each child received the PSSE for 12 weeks by the same physical therapist and had a dynamic pressure analysis before and after the PSSE. Six AIS children at a mean age of 13 years and with averaged major Cobb angle of 26° were enrolled. There was an increase in COP-AP (15%) and a decrease in the COP-ML (-25%) following the PSSE. COP-OS on the left foot shifted farther away from the midline (about 16%) as the right side moved closer (-1%), which becomes more symmetrical (Pre-PSSE: 0.86mm & Post-PSSE: 0.32mm). There were increased pressures on the left (35%) and right (26%) hallux after PSSE. Pressure metrics, especially including COP-ML, COP-AP, COP-OS, and peak pressures on the forefoot, may be opted as optimal predictors to posture improvements by the means of PSSE.

Effect on Vehicle-Pedestrian Conflicts of “Turning Traffic Must Yield to Pedestrians” Sign

1996 ◽  
Vol 1553 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Husham N. Abdulsattar ◽  
Mohammed S. Tarawneh ◽  
Patrick T. McCoy ◽  
Stephen D. Kachman
Keyword(s):  
Traffic Control ◽  
Signalized Intersections ◽  
Legal Obligation ◽  
Left Turn ◽  
Right Of Way ◽  
Two Cities ◽  
Before And After ◽  
Left And Right ◽  
Control Devices ◽  
The Right

Left- and right-turn movements at signalized intersections have been found to be three to six times more hazardous to pedestrians than through movements mainly because drivers fail to observe or yield the right of way to pedestrians. The objective was to evaluate the Turning Traffic Must Yield to Pedestrians sign, which was aimed at reminding turning motorists of their legal obligation to yield the right of way to pedestrians and, consequently, reducing vehicle-pedestrian conflicts. The sign was installed at 12 marked crosswalks in two cities, and vehicle-pedestrian conflict data were collected before and after its installation. The sign was effective in reducing left-turn conflicts 20 to 65 percent and right-turn conflicts 15 to 30 percent; both reductions were statistically significant at the 0.05 level. The sign was significantly more effective in reducing left-turn conflicts than it was for right-turn conflicts. Percentage conflicts between pedestrians and turning traffic decreased as the pedestrian group size increased. In other words, larger pedestrian group sizes encountered fewer conflicts with turning traffic. This result is true for both left- and right-turn movements, regardless of the presence of the sign. Based on the results of this study, it was recommended that the “Turning Traffic Must Yield to Pedestrians” sign be considered for inclusion in the Manual on Uniform Traffic Control Devices.

Potential for Standardization of Refractive Measures for Manifest Refraction Before and After Using Mydriatic Eyedrops in Children

2020 ◽  
Vol 12 (4) ◽  
pp. 563-569
Author(s):  
Yenling Cho ◽  
Xue Chen ◽  
Lisha Huang ◽  
Xue Yang ◽  
Yuhua Wang
Keyword(s):  
Pupil Dilation ◽  
Cluster Sampling ◽  
Significant Difference ◽  
Manifest Refraction ◽  
Before And After ◽  
Left And Right ◽  
Potential Impact ◽  
The Right

This study aimed to standardize the refractive measures using manifest refraction (MR) before and after using mydriatic eyedrops, and to explore the potential impact of age on the MR differences before mydriatic eyedrops (MRM), after rapid pupil dilation (MRRPD), and after slow pupil dilation (MRSPD). Three hundred sixty-two participants, aged 3–18 years were recruited from January 1, 2018, to September 30, 2018, using cluster sampling. MRM, MRRPD, and MRSPD were applied for measuring sphere and cylinder in the left and right eyes. At the initial inspection stage there were no significant differences between the MRM and MRRPD groups for sphere and cylinder values in the left and right eyes (P > 0 05). A significant difference was found for the sphere value in the left (P < 0 001) and right eyes (P < 0 001) among the MRM, MRRPD, and MRSPD groups, whereas there was no significant difference in cylinder value in the left (P = 0 691) and right eyes (P = 0 172) among groups at the review stage. The sphere value in the left and right eyes was significantly different among the MRM, MRRPD, and MRSPD groups for children aged 3–6 years, and there was a significant difference among groups for the sphere value in the right eye for children aged 7–11 years. There were no significant differences between the MRM and MRRPD groups in terms of sphere or cylinder values in the left and right eyes of children aged 12–18 years. The study findings indicate the results of sphere and cylinder measurements in the left and right eyes are consistent for MRM and MRRPD during the initial inspection stage, without any effect of the age of the children. However, the results of sphere measurements in the left and right eye were significantly different between the MRM, MRRPD, and MRSPD groups, especially for younger children.

Coding of Spatial Information in the Somatosensory System: Evidence from Patients with Neglect following Parietal Lobe Damage

1994 ◽  
Vol 6 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Morris Moscovitch ◽  
Marlene Behrmann
Keyword(s):  
Cerebral Hemisphere ◽  
Spatial Information ◽  
Parietal Lobe ◽  
Somatosensory System ◽  
Frame Of Reference ◽  
Lateral Side ◽  
Hand Position ◽  
Right Cerebral Hemisphere ◽  
Left And Right ◽  
The Right

Unilateral parietal lobe damage, particularly in the right cerebral hemisphere, leads to neglect of stimuli on the contra lateral side. To determine the reference frame within which neglect operates in the somatosensory system, 11 patients with unilateral neglect were touched simultaneously on the left and right side of the wrist of one hand. The hand was tested in both the palm up and the palm down position. Patients neglected the stimuli on the side of space contra lateral to the lesion regardless of hand position. These results indicate that point-localization in the somatosensory system is accomplished with respect to a spatially defined frame-of-reference and not strictly with respect to somatotopically defined coordinates.

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