Motor Preparation of Manual Aiming at a Visual Target Manipulated in Size, Luminance Contrast, and Location

Perception ◽  
10.1068/p5776 ◽  
2007 ◽  
Vol 36 (9) ◽  
pp. 1375-1390 ◽  
Author(s):  
Masami Ishihara ◽  
Kuniyasu Imanaka
Keyword(s):  
Left Visual Field ◽  
Target Location ◽  
Visual Target ◽  
Task Complexity ◽  
Motor Preparation ◽  
Luminance Contrast ◽  
Manual Aiming ◽  
Left Hand ◽  
The Difference ◽  
The Right

We conducted two experiments to investigate whether the motor preparation of manual aiming to a visual target is affected by either the physical characteristics (size or luminance contrast) or spatial characteristics (location) of the target. Reaction time (RT) of both finger lifting (ie stimulus-detection time) and manual aiming (ie movement-triggering time) to the onset of the target was measured. The difference of RT (DRT) between two tasks (ie the difference of task complexity) was examined to clarify the temporal characteristics of manual aiming per se during visuomotor integration. Results show classical characteristics: RT decreased as either the target size or luminance contrast increased. Furthermore, the task-complexity and target-location factors significantly interacted with each other, where the aiming RT was longer than the finger-lifting RT and the effects of target location on RT differed for each task. However, the task factor did not interact with either the size or luminance-contrast factor, implying that the motor preparation of manual aiming is associated with the spatial characteristics rather than the physical characteristics of the target. Inspection of DRT revealed that the time needed for motor preparation for an ipsilateral target was significantly shorter than that for a contralateral target. This was the case both for the left and for the right hand. Foveal targets required longer processing time, implying a disadvantageous function of motor preparation for the gazed target. The left-hand superiority for the target appearing in the left visual field was also observed. Such lateralised effect and left-hand advantage to the left visual field in manual aiming suggest that visuospatial information processing is activated during the preparation of aiming action, with faster processing in the right hemisphere.

STUDIES ON HABITUATION TO COLD PAIN

1966 ◽  
Vol 44 (2) ◽  
pp. 287-293 ◽  
Author(s):  
Jacques LeBlanc ◽  
Pierre Potvin
Keyword(s):  
Cold Water ◽  
Mental Arithmetic ◽  
Blood Pressure Response ◽  
Human Subjects ◽  
Cold Pain ◽  
Left Hand ◽  
Water Test ◽  
The Difference ◽  
The Right ◽  
Habituation To Cold

It was possible to produce habituation to cold in a group of human subjects by immersing the left hand in cold water for [Formula: see text] minutes twice a day for 19 days. The right hand did not adapt. Another group of subjects was exposed similarly with the difference that an anxiety test (mental arithmetic test) was always given simultaneously with the cold-water test. In this second group the original blood pressure response, i.e. for the first day, was greater than in the first group because of the cumulative effects of the two tests. After 19 days definite evidence was obtained for adaptation to these two tests administered together. However, when these tests were given separately to the second group, no adaptation was evident; adaptation occurred only to both tests given simultaneously. These results indicate that no adaptation develops to cold per se if the subjects are distracted from cold discomfort. It was also found that adaptation of one hand to cold water not only failed to induce adaptation in the opposite hand but even reinforced responses of the unadapted hand. These findings suggest a participation of the central nervous system in adaptation to cold pain, and tend to minimize the importance of local peripheral changes.

scholarly journals Refinements of the Lower Bounds of the Jensen Functional

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Iva Franjić ◽  
Sadia Khalid ◽  
Josip Pečarić
Keyword(s):  
Lower Bounds ◽  
Jensen Inequality ◽  
Left Hand ◽  
Right Hand ◽  
Special Cases ◽  
Jensen Functional ◽  
The Difference ◽  
The Right

The lower bounds of the functional defined as the difference of the right-hand and the left-hand side of the Jensen inequality are studied. Refinements of some previously known results are given by applying results from the theory of majorization. Furthermore, some interesting special cases are considered.

Foot Performance of Right- and Left-Handers: A Question of Environmental Influence

1995 ◽  
Vol 80 (2) ◽  
pp. 671-674 ◽  
Author(s):  
Carl Gabbard ◽  
Susan Hart
Keyword(s):  
Environmental Influence ◽  
Hand Preference ◽  
Adequate Explanation ◽  
Driving Experience ◽  
Left Hand ◽  
Left Handed ◽  
Right Hand ◽  
Theoretical Perspectives ◽  
The Difference ◽  
The Right

Prior research has shown that right-handed adults perform better on a speed-tapping task with the right hand and right foot, while left-handers execute more rapidly with the left hand and right foot. Speculation is that environmental influence, most likely driving experience, may account for the right-foot bias. To examine this hypothesis further, 48 young right- and left-handed children were tested on a similar protocol. Analyses indicated no significant differences in foot performance within hand-preference groups. Since these findings do not complement reports for adults, factors such as experience or maturation might contribute to the difference. Were patterns similar, the effect of environmental influence would be assumed to be small. However, much more evidence is needed before an adequate explanation can be developed. The issue of possible environmental influence is discussed from various theoretical perspectives.

Ipsilateral Motor Cortex Activity During Unimanual Hand Movements Relates to Task Complexity

2005 ◽  
Vol 93 (3) ◽  
pp. 1209-1222 ◽  
Author(s):  
Timothy Verstynen ◽  
Jörn Diedrichsen ◽  
Neil Albert ◽  
Paul Aparicio ◽  
Richard B. Ivry
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Time Course ◽  
Right Hemisphere ◽  
Task Complexity ◽  
Hand Movements ◽  
Left Hand ◽  
Sequential Structure ◽  
Single Finger ◽  
The Right

Functional imaging studies have revealed recruitment of ipsilateral motor areas during the production of sequential unimanual finger movements. This phenomenon is more prominent in the left hemisphere during left-hand movements than in the right hemisphere during right-hand movements. Here we investigate whether this lateralization pattern is related specifically to the sequential structure of the unimanual action or generalizes to other complex movements. Using event-related fMRI, we measured activation changes in the motor cortex during three types of unimanual movements: repetitions of a sequence of movements with multiple fingers, repetitive “chords” composed of three simultaneous key presses, and simple repetitive tapping movements with a single finger. During sequence and chord movements, strong ipsilateral activation was observed and was especially pronounced in the left hemisphere during left-hand movements. This pattern was evident for both right-handed and, to a lesser degree, left-handed individuals. Ipsilateral activation was less pronounced in the tapping condition. The site of ipsilateral activation was shifted laterally, ventrally, and anteriorly with respect to that observed during contralateral movements and the time course of activation implied a role in the execution rather than planning of the movement. A control experiment revealed that strong ipsilateral activity in left motor cortex is specific to complex movements and does not depend on the number of required muscles. These findings indicate a prominent role of left hemisphere in the execution of complex movements independent of the sequential nature of the task.

Uncertainty of sweat chloride testing: does the right hand know what the left hand is doing?

2008 ◽  
Vol 45 (6) ◽  
pp. 535-538 ◽  
Author(s):  
R J Mackay ◽  
C M Florkowski ◽  
P M George ◽  
C W Sies ◽  
S Woods
Keyword(s):  
Total Variation ◽  
Coefficient Of Variation ◽  
Age Groups ◽  
Chloride Concentration ◽  
Sweat Test ◽  
Left Hand ◽  
Sweat Chloride ◽  
The Difference ◽  
The Right ◽  
Analytical Variation

Although analytical variation in sweat electrolyte testing can be easily estimated, there is limited data on total variation. This study aims to evaluate the total variation of the sweat test by measuring the difference between sweat electrolyte values in specimens obtained simultaneously from two sites. Chloride is recommended in published guidelines as the only discriminant for the diagnosis of cystic fibrosis, and sodium may be measured as a guide to the adequacy of collection and analysis. Both are reported here. Sweat was collected in patients by the Gibson Cooke method from two sites simultaneously. Coefficient of variation in this laboratory is 4.1 and 5% for chloride and sodium, respectively. 295 patients had sufficient sweat collected from both sites for analysis. The values for chloride and sodium were compared between the two sites. The total coefficient of variation (CVt) calculated for the whole group between the two sites was 20.2% for chloride and 16.9% for sodium, and the standard deviations 4.3 mmol/L and 4.8 mmol/L, respectively. In patients with intermediate chloride concentrations; in different age groups; and when those tests with a difference between sodium and chloride concentration of more than 15 were excluded, minimal differences in these figures were observed. Use of strictly defined cut-off points to discriminate between normal and intermediate electrolyte values, and between intermediate and raised electrolyte values, does not reflect the variation in sweat electrolyte content found within an individual patient. This has important implications for reporting.

CT Image Measurement and Analysis of the Influence of Different Motion Modes on the Geometrical Morphology of Carpal Bone

2020 ◽  
Vol 10 (4) ◽  
pp. 913-917
Author(s):  
Zegang Wang
Keyword(s):  
Three Dimensional ◽  
Ct Imaging ◽  
Bone Volume ◽  
Carpal Bone ◽  
Left Hand ◽  
Motion Modes ◽  
Measurement And Analysis ◽  
The Difference ◽  
The Right ◽  
Capitate Bone

The purpose of this study is to explore the influence of different movement modes on the geometrical morphology of carpal bones. In this study, Computed Tomography (CT) imaging is used for measurement and analysis. The results show that the changes of wrist bone volume of athletes are not significant compared with that of non-athletes, and the changes of bone density of the wrist bone are more obvious under the motion stress stimulation. According to results of CT imaging measurement and calculation, the average CT values of triangular bone, trapezoid bone, capitate bone and pisiform bone in the left hand and hamate bone in the right hand of the athlete are greater than that of the non-athlete, and the difference is statistically significant. Therefore, CT imaging technology can help to reconstruct the three-dimensional image of the carpal bone and deeply understand the geometric shape of the carpal bone of athletes.

Some Factors in the Recognition of Tachistoscopically Presented Alphabetical Arrays

1972 ◽  
Vol 35 (3) ◽  
pp. 951-959 ◽  
Author(s):  
Robert Fudin ◽  
John T. Kenny
Keyword(s):  
Visual Field ◽  
Left Visual Field ◽  
Retinal Location ◽  
Right Visual Field ◽  
Central Fixation Point ◽  
Information Delay ◽  
The Difference ◽  
The Right ◽  
The Relationship ◽  
Central Fixation

Six-letter nonsense arrays, constructed from a 12-letter population which was not made known to 20 Ss, were tachistoscopically shown successively in the right visual field (RVF) and left visual field (LVF) at three displacements from a central fixation point. Recognition scores were higher for stimuli in the RVF at each displacement. In each case RVF superiority was limited to letters in the first array-half (letters 1, 2, 3). These results agree with prior findings obtained with targets made up of six letters known to S (Fudin, 1969). Reportability of a tachistoscopically exposed letter, in part, is a function of the relationship between its retinal location and the delay before it is scanned. Location determines the amount of information a letter contains before it starts to fade-out (the more acute the area, the greater the information), delay determines the period of information dissipation prior to scanning. These ideas were used to explain the contrast between high error scores for middle-array letters in the bow-shaped error curves found in this experiment and the low values often reported for these letters when targets are shown across fixation, and the finding that the difference between error scores for letters in the first and second array-halves was greater for targets at each displacement in the right than the left visual field.

scholarly journals Problems with perfect-looking two-needle decorative seams in the manufacture of leather car seat covers

2019 ◽  
Vol 90 (1) ◽  
pp. 49-62
Author(s):  
Katarina Zelova ◽  
Viera Glombikova ◽  
Antonin Havelka
Keyword(s):  
Causal Link ◽  
Visual Evaluation ◽  
Slant Angle ◽  
Left Hand ◽  
Sewing Thread ◽  
Penetration Force ◽  
The Difference ◽  
The Right ◽  
Cutting Point ◽  
Needle Point

This study objectively evaluates the uneven appearance of the two-needle decorative seams of leather seat covers. The investigation is based on both measurement of the stitch slant angle by image analysis and measurement of the penetration force influenced by different cutting points of the needles. To record the unevenness the new parameter, the difference of the stitch slant between the right- and left-hand sides of the seam was evaluated. Further, the interrelation ship among penetration force differences of the stitch slant and type of needle point was searched for to meet the requirements of car producers for a perfect appearance of decorative seams. The degree of uneven seam was measured within subjective visual evaluation, too. Four natural and two artificial leathers were tested. A combination of two threads and four needle points was applied to the tested leathers. It was confirmed that the uneven appearance was influenced by the type of leather, the point of the sewing needle and by the sewing thread. The selection of the needle point influenced the size of the force required for penetrating the leather. It was determined only in half of the cases that the smaller the force of penetration, the more even the appearance of the decorative seam. In most cases, using the cutting point LR, the left seam looked less slanted than the right one. Conversely, when using the cutting point for straight stitch appearance, that is, DH, the left stitch looked straighter than the right one. The causal link between the new parameter Δβ and the suitability of the applied needles and threads for leather materials was found.

scholarly journals Association between the 2D:4D ratio and schizophrenia

2020 ◽  
Vol 48 (6) ◽  
pp. 030006052092914
Author(s):  
Yuanyuan Han ◽  
Wei Deng ◽  
Wei Lei ◽  
Yin Lin ◽  
Yinfei Li ◽  
...  
Keyword(s):  
Sexually Dimorphic ◽  
Healthy Controls ◽  
Statistical Manual ◽  
Left Hand ◽  
Diagnostic And Statistical Manual ◽  
Potential Association ◽  
Male Patients ◽  
The Difference ◽  
The Right ◽  
Digit Length

Objective To investigate the potential association between the ratio of the second digit length to the fourth digit length (2D:4D) and schizophrenia, to provide evidence regarding the pathogenesis of schizophrenia. Methods In this study, we enrolled 843 patients with schizophrenia (387 men and 456 women), all of whom met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and 1050 normal healthy controls (477 men and 573 women). The digit lengths of both hands were measured in all subjects and the 2D:4D ratio was analyzed. Results In the healthy controls, the 2D:4D ratio was sexually dimorphic, with a larger value in women than in men. In addition, the 2D:4D ratio in the schizophrenia patients was significantly larger than in the healthy controls. The 2D:4D ratio of the right hand was more sexually dimorphic than the left hand. Furthermore, the difference in 2D:4D ratios between the male patients and male controls was significantly larger than in their female counterparts. Conclusions By analyzing the 2D:4D ratio and considering alternative factors related to schizophrenia, our findings support the hypothesis that there are abnormal cerebral conditions in schizophrenia patients.

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