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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two experiments were conducted to determine the spatial and temporal organization of the arm trajectory in human subjects as they pointed to single- and double-step target displacements. Subjects pointed either without (Experiment 1) or with (Experiment 2) vision of their moving hand throughout the trial. In both experiments, target perturbation occurring in double-step trials was clearly perceived by the subjects and was randomly introduced either at the onset or at peak velocity of hand movement. Regardless of whether or not visual reafference from the pointing hand was available, subjects corrected the trajectory of their moving hand to accommodate the double-step. Moreover, asymmetrical velocity profiles were observed for responses to both types of target, with or without vision of the moving hand. The acceleration phase was a fixed pattern independent of the type of step stimulation. However, a clear dissociation, both in the deceleration phase and accuracy of responses to double-step targets, emerged according to the timing of target perturbation. When targets were perturbed at the onset of hand movement, subjects modulated the deceleration phase of their response to compensate for 88 to 100% of the second target displacement. In contrast, when targets were perturbed at peak velocity of hand movement, subjects were unable to modulate the deceleration phase adequately and compensated for only 20 to 40% of the perturbation. These results suggest that motor error is dynamically evaluated during the acceleration phase of a movement toward a perturbed target, allowing amendments to the trajectory to be performed during the deceleration phase. This main corrective process appears to be basically independent of visual reafference from the moving hand.
J Mot Behav 1993 Dec
PMID:Error processing in pointing at randomly feedback-induced double-step stimuli. 1506 96

This study investigated the magnitude of the asymmetrical tonic neck reflex (ATNR) response in forty preschool children, grouped by age (3 years and 5 years) and sex. The ATNR response was measured by electrogoniometers at the head and elbows and recorded graphically on an X-Y plotter. Change scores indicating the difference in degrees of elbow flexion before and after head rotation were analyzed. Repetition of the stimulus (head turning) to the left and to the right occurred under two test postures (supine, quadrupedal) with the effect of a blindfold nested within quadruped trials and the effect of added tension nested within supine, totaling 16 trials per child. The magnitude of the ATNR decreased significantly with age, but sex differences were not significant. The quadrupedal test posture produced significant increases in the supine posture. The blindfold did not produce significant main effects. Electrogoniometric measurement consistently demonstrated the magnitude of the ATNR in normal preschool children, which decreases with age, is dependent upon test posture and can provide numerical guides in clinical tests of central nervous system integration.
J Mot Behav 1984 Sep
PMID:Notes on measurement of the magnitude of the asymmetrical tonic neck reflex response in normal preschool children. 1515 57

The reaction-time probability effect on isolated trials was found to be asymmetrical in an experiment on 64 college students. There was a large drop in RT for a high-probability probe trial embedded in a block of low-probability trials, but a much smaller rise for a low-probability trial embedded in high-probability trials. Thus, low- but not high-probability responses seem to be influenced by characteristics of the trial block. If the basis of the probability effect were the strategic placement of the criterion for response initiation, symmetrical results should have been obtained. A motivational account which accords with the present data is that the subject is ordinarily willing to prepare but is averse to doing so in some (not entirely specified) low-probability circumstances.
J Mot Behav 1978 Sep
PMID:Reaction time and probability on isolated terms. 1518 84

The study of lateralization processes in olfaction in human subjects has given rise to many contradictory findings. Indeed, sensorial cerebral asymmetry in olfaction depends on several factors (nature of task, quality of stimulus, characteristics of subjects, etc.) and could be also related to differences between the nostrils. In this field, few studies have assessed simultaneously the left-right nostril differences and the hemispheric asymmetry. The present work dealt with this question in the same population with the same odorants, procedures, and stimulations. Seven different concentrations of four specific odorants (two pleasant and two unpleasant) were used by single nostril stimulation with 30 dextral subjects (20 women and 10 men). Threshold detection in unilateral stimulation was investigated using electrodermal response to confirm the first psychophysic measure. Moreover, bilateral recordings of electrodermal activity (EDA) with unilateral stimulation were used as a measure of functional hemispheric asymmetry. Analysis showed no differences between the two nostrils for the threshold detection regardless of the method used (psychophysic or EDA response). However, most subjects presented a constant direction of electrodermal asymmetry whichever nostril was stimulated and whichever odorant stimulus used. The constant bilateral differences in EDA recordings are discussed in terms of asymmetrical activation of the hemispheres.
Percept Mot Skills 2004 Jun
PMID:Left:right differences in psychophysical and electrodermal measures of olfactory thresholds and their relation to electrodermal indices of hemispheric asymmetries. 1520 88

Rats move their whiskers actively during tactile exploration of their environment. The whiskers emanate from densely innervated whisker follicles that are moved individually by intrinsic facial muscles and as a group by extrinsic muscles. Several descriptions of whisker movements in normal adult rats during unrestrained exploration indicate that rats move their whiskers in the 6-9 Hz range when exploring a new environment. The rate can be elevated to nearly 20 Hz for brief episodes just prior to making a behavioural decision. The present studies were undertaken to compare whisker dynamics in head-restrained and freely moving rats with symmetrical or asymmetrical numbers of whiskers on the two sides of their face and to provide a description of differences in whisker use in exploring rats after trimming all but two whiskers on one side of the face, a condition that has been shown to induce robust cortical plasticity. Head-fixed rats were trained to protract their whiskers against a contact detector with sufficient force to trigger a chocolate milk reward. Whisker movements were analyzed, and the results from head-fixed animals were compared with free-running animals using trials taken during their initial exploration of novel objects that blocked the rat's progress down an elevated runway. The results show that symmetrical whisker movements are modulated both by the nature of the task and the number of whiskers available for exploration. Rats can change their whisker movements when the sensitivity (threshold) of a contact detector is raised or lowered, or when the nature of the task requires bilateral input from the whiskers. We show that trimming some, but not all whiskers on one side of the face modifies the synchrony of whisker movement compared to untrimmed or symmetrically trimmed whiskers.
Somatosens Mot Res 2005 Sep
PMID:Comparison of bilateral whisker movement in freely exploring and head-fixed adult rats. 1633 19

32 Japanese participants drew symmetrical and asymmetrical letters on their own foreheads. By observing their drawing strokes, it was judged that 29 of them drew symmetric letters in reverse, that is, as if these were viewed from inside the head. However, 14 of these 29 seemed to have noticed their reversed perception because they drew asymmetric letters intentionally reversed so they would appear correct when viewed from outside. Only three participants drew the letters in a normal way irrespective of the letter symmetry.
Percept Mot Skills 2005 Dec
PMID:Elicitation of spontaneous mirror reversal drawing on the forehead. 1649 95

The aim of the study was to investigate the effect of a muscular training program on soccer players' performance which initially appeared imbalanced or bilaterally asymmetrical. During the preparation period, 35 soccer players performed an isokinetic measurement of knee flexors and extensors (60 degrees(-1) and 180 degrees sec.(-1)). 15 of these had muscular imbalances or deficits and followed a specific isokinetic training program for 2 mo., 3 times per week. After the completion of the isokinetic training program, the 35 players underwent the same isokinetic test. Significant differences were noted between the pre- and posttraining measures at both angular velocities in peak torque values, in differences from one limb to the other, and in peak torque ratios for flexors and extensors. Consequently, the application of this specific isokinetic training program can restore imbalances in knee muscle strength efficiently.
Percept Mot Skills 2006 Aug
PMID:Soccer players' muscular imbalances: restoration with an isokinetic strength training program. 1703 56

The present study examined interactions of speech production and finger-tapping movement, using a syncopated motor task with two movements in 10 male right-handed undergraduate students (M age = 21.0 yr.; SD = 1.4). On the syncopated task, participants were required to produce one movement exactly midway between two other movements (target interresponse interval: 250 msec.). They were divided into two groups, the tap-preceding group and speech-preceding group. The author observed that the right hand showed a more variable peak force and intertap interval than the left hand in the speech-preceding group, indicating an asymmetrical interference of two movements. On the other hand, the mean differences between onsets of speech and tapping movement were shorter than 250 msec. over all conditions (the shortest mean difference was 50 msec.), suggesting a mutual entrainment of two movements. An asymmetry of entrainment was observed in the speech-preceding group, in which speech production was more strongly entrained with movements of the right hand than with those of the left hand.
Percept Mot Skills 2007 Oct
PMID:Interactions of speech and manual movement in a syncopated task. 1806 66

The aim of this study was to investigate the dynamic nature of the cortical visuospatial attention processes during the line bisection test, which is sensitive to perceptual asymmetries. EEGs of 26 normal volunteers were recorded during the administration of a computerized line bisection test, which requires participants mark the midline of lines using a mouse. Two event-related potentials subsequent and time locked to the line presentations, namely, P300 and a positive slow wave, were obtained. Findings suggested that both potentials were related to the test performance, and the right hemisphere was more active. Analysis suggested a right parietotemporal and superior parietal locus for the P300 and right prefrontal activity for the positive slow wave. A dynamic asymmetrical activity was identified, such that after primary visual perception, spatial processing is then initiated in the right parietotemporal cortex and then proceeds to the right prefrontal cortex.
Percept Mot Skills 2007 Oct
PMID:Frontal and posterior ERPs related to line bisection. 1806 83

The interference effect between Grooved Pegboard task with either hand and the executive task of cued verbal random number generation was investigated. 24 normal right-handed subjects performed each task under separate (single-task) and concurrent (dual-task) conditions. Articulatory suppression was required as an additional secondary task during pegboard performance. Analysis indicated an unambiguous distinction between the two hands. Comparisons of single-task and dual-task conditions showed an asymmetrical pattern of unidirectional interference with no practice effects during pegboard performance. Concurrent performance with nondominant hand but not the dominant hand of random number generation performance became continuously slower. There was no effect of divided attention on pegboard performance. Findings support the idea that the nondominant hand on the pegboard and random number tasks draw from the same processing resources but that for the executive aspect random number generation is more sensitive to changes in allocation of attentional resources.
Percept Mot Skills 2008 Jun
PMID:Unidirectional interference in use of nondominant hand during concurrent Grooved Pegboard and random number generation tasks. 1871 98


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