scholarly journals Integration of Proprioceptive and Visual Position-Information: An Experimentally Supported Model

1999 ◽  
Vol 81 (3) ◽  
pp. 1355-1364 ◽  
Author(s):  
Robert J. van Beers ◽  
Anne C. Sittig ◽  
Jan J. Denier van der Gon

Integration of proprioceptive and visual position-information: an experimentally supported model. To localize one’s hand, i.e., to find out its position with respect to the body, humans may use proprioceptive information or visual information or both. It is still not known how the CNS combines simultaneous proprioceptive and visual information. In this study, we investigate in what position in a horizontal plane a hand is localized on the basis of simultaneous proprioceptive and visual information and compare this to the positions in which it is localized on the basis of proprioception only and vision only. Seated at a table, subjects matched target positions on the table top with their unseen left hand under the table. The experiment consisted of three series. In each of these series, the target positions were presented in three conditions: by vision only, by proprioception only, or by both vision and proprioception. In one of the three series, the visual information was veridical. In the other two, it was modified by prisms that displaced the visual field to the left and to the right, respectively. The results show that the mean of the positions indicated in the condition with both vision and proprioception generally lies off the straight line through the means of the other two conditions. In most cases the mean lies on the side predicted by a model describing the integration of multisensory information. According to this model, the visual information and the proprioceptive information are weighted with direction-dependent weights, the weights being related to the direction-dependent precision of the information in such a way that the available information is used very efficiently. Because the proposed model also can explain the unexpectedly small sizes of the variable errors in the localization of a seen hand that were reported earlier, there is strong evidence to support this model. The results imply that the CNS has knowledge about the direction-dependent precision of the proprioceptive and visual information.

Archaeologia ◽  
1853 ◽  
Vol 35 (1) ◽  
pp. 190-193
Author(s):  
John Yonge Akerman

With the exception of Figs. 1, 2, 3, the Gold Ornaments engraved in Plate VIII. have no reference whatever to each other. The first three were obtained by Viscount Strangford, Director of the Society, from a Greek priest at Milo, in the year 1820. Figs. 1 and 3 appear to have formed the ends of a light chain, and the other (fig. 2) to have been pendent by a small loop on the top of the head. The figure has unfortunately lost the feet and the left hand, but the other parts are perfect. The right hand is raised in an admonitory attitude. The forehead appears as if encircled with a wreath, while the body is crossed by what would seem to be intended for the tendril of a vine. The necklace was formerly in the collection of the late Mr. H. P. Borrell, of Smyrna, but I am informed by his brother, Mr. Maximilian Borrell, who now possesses it, that no record exists of its discovery, and that he cannot learn the name of the individual from whom it was purchased. It was well known that Mr. H. P. Borrell was in the habit of purchasing ancient coins, which were sent to him from all parts of Greece and Asia-Minor, and that many rare and unique specimens fell into his hands, of which he contributed descriptions in various volumes of the Numismatic Chronicle. The necklace may, therefore, have been included in one of these numerous consignments, and we can scarcely indulge the hope that the place of its discovery will ever be made known. As an example of ancient art, it may vie with the most elaborate and beautiful specimens of goldsmiths' work of any age or period. The details are wonderfully minute and delicate, even the backs of the button-like objects at the ends of the pendent cords being elaborately finished.


1930 ◽  
Vol 50 (1) ◽  
pp. 140-141
Author(s):  
J. D. Beazley

Miss Hutton's valuable article on the archaistic reliefs in Oxford contains two errors, which may as well be corrected at once. The first was pointed out to me by Mr. W. H. Buckler. Of the left-hand nymph in the representation of Pan teased, Miss Hutton writes that the artist ‘twisted the upper portion of her body round into a three-quarters frontal position, which he balanced by flinging the right arm back to fill the empty space behind the body. There is therefore no physical contact between the first nymph and Pan.’ As a matter of fact she was grasping the end of Pan's leopard-skin with her right hand, just as in the other reliefs with the same subject, and swinging not her right but her left arm back.The second slip is in the account of the Rhodian nymph relief. According to Miss Hutton, ‘the whole surface has been so much rubbed down to conceal damage that the right-hand figure, whose heavy peplos had originally a pleated kolpos with swallow-tail points, appears to be clad in a transparent veil over an equally transparent tunic.’


2021 ◽  
Vol 9 (11) ◽  
pp. 907-911
Author(s):  
Gwunireama I.U. ◽  
◽  
Ogoun T.R. ◽  
Adheke O.M. ◽  
Wariboko L.I. ◽  
...  

Vitiligo is a skin pigmentation disorder that is caused by a loss of melanocytes, characterized by white spots around certain parts of the body. The aim of this study was to investigate the relationship between digit length, digit (2D:4D) ratio and vitiligo among vitiligo patients within a south-southern Nigeria. Informed consents were obtained from 98 vitiligo adult subjects (69 females and 29 males) in the age range of 18 – 50 years. The measurements that were obtained were the digit lengths of second and fourth fingers for both hands using the digital vernier caliper. The mean and standard deviation values were calculated for all measurements. A Pearson correlation was used to analyse the relationship between the various measurements for both hands in the study. Results showed that the mean ± standard deviation of the various parameters for the female category. Right 2D length was 6.67± 7.53cm, left 2D length was 6.68 ± 7.32cm, right 4D length and left 4D length were 6.86 ± 8.57cm and 6.89 ± 8.50cm respectively. While, the mean and standard deviation values for right and left 2D:4D ratios for the female category were 0.98 ± 0.15 and 0.98 ± 0.12 respectively. In the males, right 2D length was 6.66 ± 9.66cm, left 2D length was 6.64 ± 9.86cm, right 4D length and left 4D length were 6.99 ± 10.09cm and 7.03± 10.40cm respectively. While, the mean and standard deviation values for right and left 2D:4D ratios for the male category were 0.95 ± 0.03 and 0.95 ± 0.03 respectively. In the females for the right hand, there was a significant positive correlation between 2D length and 4D length (r = 0.761, p = 0.000) while there was a significant negative correlation between 4D length and digit ratio (r = -0.473, p = 0.000) at p < 0.01. For the left hand, there was a significant positive correlation between 2D length and 4D length (r = 0.783, p = 0.000). In the males for the right hand, there was a significant positive correlation between 2D length and 4D length (r = 0.976, p = 0.000). For the left hand, there was a significant positive correlation between 2D length and 4D length (r = 0.981, p = 0.000).It can be concluded that the knowledge of 2D:4D ratio among vitiligosubjects could be helpful in clinical anthropometry however, more research has to be done considering that the sample size of this study is relatively small.


2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Velarie Ansu ◽  
Stephanie Dickinson ◽  
Alyce Fly

Abstract Objectives To determine which digit and hand have the highest and lowest skin carotenoid scores, to compare inter-and-intra-hand variability of digits, and to determine if results are consistent with another subject. Methods Two subjects’ first(F1), second(F2), third(F3) and fifth(F5) digits on both hands were measured for skin carotenoids with a Veggie Meter, for 3 times on each of 18 days over a 37-day period. Data were subjected to ANOVA in a factorial treatment design to determine main effects for hand (2 levels), digits (4), and days (18) along with interactions. Differences between digits were determined by Tukey's post hoc test. Results There were significant hand x digit, hand x day, digit x day, and hand x digit x day interactions and significant simple main effects for hand, digit, and day (all P < 0.001). Mean square errors were 143.67 and 195.62 for subject A and B, respectively, which were smaller than mean squares for all main effects and interactions. The mean scores ± SD for F1, F2, F3, and F5 digits for the right vs left hands for subject A were F1:357.13 ± 45.97 vs 363.74 ± 46.94, F2:403.17 ± 44.77 vs. 353.20 ± 44.13, F3:406.76 ± 43.10 vs. 357.11 ± 45.13, and F5:374.95 ± 53.00 vs. 377.90 ± 47.38. For subject B, the mean scores ± SD for digits for the right vs left hands were F1:294.72 ± 61.63 vs 280.71 ± 52.48, F2:285.85 ± 66.92 vs 252.67 ± 67.56, F3:268.56 ± 57.03 vs 283.22 ± 45.87, and F5:288.18 ± 34.46 vs 307.54 ± 40.04. The digits on the right hand of both subjects had higher carotenoid scores than those on the left hands, even though subjects had different dominant hands. Subject A had higher skin carotenoid scores on the F3 and F2 digits for the right hand and F5 on the left hand. Subject B had higher skin carotenoid scores on F5 (right) and F1 (left) digits. Conclusions The variability due to hand, digit, and day were all greater than that of the 3 replicates within the digit-day for both volunteers. This indicates that data were not completely random across the readings when remeasuring the same finger. Different fingers displayed higher carotenoid scores for each volunteer. There is a need to conduct a larger study with more subjects and a range of skin tones to determine whether the reliability of measurements among digits of both hands is similar across the population. Funding Sources Indiana University.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Biggio ◽  
A. Bisio ◽  
F. Garbarini ◽  
Marco Bove

AbstractCircle-line drawing paradigm is used to study bimanual coupling. In the standard paradigm, subjects are asked to draw circles with one hand and lines with the other hand; the influence of the concomitant tasks results in two “elliptical” figures. Here we tested whether proprioceptive information evoked by muscle vibration inducing a proprioceptive illusion (PI) of movement at central level, was able to affect the contralateral hand drawing circles or lines. A multisite 80 Hz-muscle vibration paradigm was used to induce the illusion of circle- and line-drawing on the right hand of 15 healthy participants. During muscle vibration, subjects had to draw a congruent or an incongruent figure with the left hand. The ovalization induced by PI was compared with Real and Motor Imagery conditions, which already have proved to induce bimanual coupling. We showed that the ovalization of a perceived circle over a line drawing during PI was comparable to that observed in Real and Motor Imagery condition. This finding indicates that PI can induce bimanual coupling, and proprioceptive information can influence the motor programs of the contralateral hand.


1923 ◽  
Vol 25 ◽  
pp. 408-428
Author(s):  
C. A. Boethius
Keyword(s):  

Among the ruins of the Hellenistic buildings at the south end of the Great Ramp, in the fourth or southern chamber (Pl. I. 34), three fragments of a stele (now in the Nauplia Museum) were found. The stele is of a simple and common type, and is made of the same white limestone as the other Mycenaean stele found by Tsountas, which it closely resembles even in its weathering. Except for the top left-hand corner and a gap on the right side the whole stele is preserved. It is ·969 m. in height, ·41–·436 m. in breadth (·41 m. at the ninth line of the inscription) and ·11–·125 m. thick. At the top there is a plain frieze, ·065 m. high : ·02 m. below the frieze begins an inscription which fills twenty lines and ends ·50 m. above the bottom of the stele. The letters are ·008–·01 m. high. The space between the lines is ·009–·011 m. The surface of the stone is very much worn, and it was consequently difficult to make out the letters and their accurate forms. The sketch (Fig. 93) shows the arrangement of the text.


2018 ◽  
Vol 89 (9) ◽  
pp. 1712-1724 ◽  
Author(s):  
Mingrui Guo ◽  
Fengxin Sun ◽  
Lei Wang ◽  
Yuan Xue ◽  
Ruihua Yang ◽  
...  

The main aim of this paper is to investigate the fiber distribution on the surface of a kind of novel two-color yarn spun by regulating the feeding ratio of two colored rovings on a modified ring spinning frame, which is named the double-channel spinning frame. The surface distribution ratio ( SDR) and the coefficient of variation of surface distribution evenness ( CV sd) of the two colored fiber strands in the yarns was used to quantify the fiber distribution feature along the yarns based on a purpose-made image acquisition device and the corresponding image processing method. The effect of the weight ratio, roving feeding position and spinning method on the mean SDR and CV sd were studied, and the testing results of the Z-twist and S-twist two-color yarns spun by a modified traditional ring spinning frame as well as the yarns spun by a modified compact spinning frame were compared with each other. The fibers of the left-hand roving are more likely to distribute in the surface of Z-twist yarn, while the fibers of the right-hand roving tend to distribute in the surface of S-twist yarn. Four linear fitting equations of the 19.4 tex Z-twist and S-twist two-color ring spun yarns and two-color compact spun yarns were developed to predict the relationships between the mean SDR and weight ratio of two colored fibers.


1867 ◽  
Vol 15 ◽  
pp. 220-222

In a paper “ On the Expansion by Heat of Water and Mercury” *, a method of determining the expansion of bodies is described, by which good results can be obtained with comparatively small quantities of the substances to be experimented with. This method, that of weighing the body in water at different temperatures, has been employed for the present research. The results obtained are given in the following Tables:— From the above the following conclusion is drawn-namely, that just as it may be said that the specific gravity of an alloy is approximately equal to the mean specific gravities of the component metals , so also from the foregoing we may deduce that the volume which an alloy will occupy at any temperature between 0° and 100° is approximately equal to the mean of the volumes o f the component metals at the same temperature, or, in the other words, the cubical or linear coefficients o f expansion by heat of an alloy between 0° and 100° are approximately equal to the mean of the cubical or linear coefficients of expansion by heat o f the component metals .


2018 ◽  
Vol 120 (2) ◽  
pp. 729-740 ◽  
Author(s):  
Elizabeth J. Woytowicz ◽  
Kelly P. Westlake ◽  
Jill Whitall ◽  
Robert L. Sainburg

Two contrasting views of handedness can be described as 1) complementary dominance, in which each hemisphere is specialized for different aspects of motor control, and 2) global dominance, in which the hemisphere contralateral to the dominant arm is specialized for all aspects of motor control. The present study sought to determine which motor lateralization hypothesis best predicts motor performance during common bilateral task of stabilizing an object (e.g., bread) with one hand while applying forces to the object (e.g., slicing) using the other hand. We designed an experimental equivalent of this task, performed in a virtual environment with the unseen arms supported by frictionless air-sleds. The hands were connected by a spring, and the task was to maintain the position of one hand while moving the other hand to a target. Thus the reaching hand was required to take account of the spring load to make smooth and accurate trajectories, while the stabilizer hand was required to impede the spring load to keep a constant position. Right-handed subjects performed two task sessions (right-hand reach and left-hand stabilize; left-hand reach and right-hand stabilize) with the order of the sessions counterbalanced between groups. Our results indicate a hand by task-component interaction such that the right hand showed straighter reaching performance whereas the left hand showed more stable holding performance. These findings provide support for the complementary dominance hypothesis and suggest that the specializations of each cerebral hemisphere for impedance and dynamic control mechanisms are expressed during bilateral interactive tasks. NEW & NOTEWORTHY We provide evidence for interlimb differences in bilateral coordination of reaching and stabilizing functions, demonstrating an advantage for the dominant and nondominant arms for distinct features of control. These results provide the first evidence for complementary specializations of each limb-hemisphere system for different aspects of control within the context of a complementary bilateral task.


2019 ◽  
Author(s):  
Jill A. Dosso ◽  
Romeo Chua ◽  
Daniel J. Weeks ◽  
David J. Turk ◽  
Alan Kingstone

Each cerebral hemisphere primarily controls and receives sensory input with regard to the contralateral hand. In the disconnected brain (split-brain), when the hands are uncrossed, direct visual access to each hand is available to the controlling (contralateral) hemisphere. However, when a hand crosses the midline, visual and tactile information regarding the hand are presented to different hemispheres. It is unknown how a contralateral hemi- sphere codes the position and orientation of a visually inaccessible hand in the discon- nected brain. The present work addresses this issue. We ask how each hemisphere represents “its” hand across hand positions that span the midline in the absence of cortical input from the contralateral hemisphere. In other words, when a hand is placed across the midline and is visually inaccessible, is it represented by the controlling hemisphere: (1) in accordance with its new position with respect to the body (e.g., a left hand “becomes” a right effector when it crosses the midline), (2) with left/right position information unal- tered (e.g., the left hand is represented as “left” regardless of its location), or (3) stripped of its location information altogether? The relationship between hand position and the spatial codes assigned to potential responses (an index of hand representation) was investigated in two split-brain patients using direct (Experiment 1) and orthogonal (Experiment 2) S-R compatibility paradigms. S-R compatibility effects in split-brain patients were consistent with those displayed by typical individuals. These findings suggest that position-based compatibility effects do not rely on cross-cortical connections. Rather, each hemisphere can accurately represent the full visuomotor space, a process that appears to be subserved by subcortical connections between the hemispheres.


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