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

17 college students discriminated between vertical and horizontal target lines flanked by vertical and horizontal distractors. Large displays with 3.0-cm lines and small displays half this size were used. The distractors were positioned above and below the target or to the left and right of it, forming vertical and horizontal global orientations. The number of flankers sharing the target's orientation was varied. Vertical targets and small display sizes were processed more quickly. Speed of responding did not differ for the two global orientations. There was no advantage for target lines consistent with global orientation. The results were replicated in Exp. 2 with diagonal flankers. This supports an explanation using stimulus compatibility, since diagonal lines do not correspond to either of the response options and cannot induce a tendency to respond more to one target than another. Displays with multiple symmetry were responded to faster than those with a single symmetry which were faster than asymmetrical displays, supporting the idea that symmetrical axes parallel and perpendicular to the target orientation provide a facilitative frame of reference. Coactivation from same-oriented flankers, pop-out from differences in orientation, and symmetry all influenced responding in these patterns.
Percept Mot Skills 2000 Feb
PMID:Coactivation, pop-out, and symmetry affect line discrimination. 1076 89

Alterations in the numerical density and structure of asymmetrical synapses were examined in thin sections through barrel D4 in six CD/1 mice, including three controls and three sensory deprived animals. Sensory deprivation was effected by once daily trimming of all large mystacial vibrissae on the contralateral side of the snout from P0. The mice were perfuse-fixed at P20, several days following the termination of rapid synaptic growth during barrel development (White et al., Somatosens Mot Res 14: 34-55, 1997). Cerebral hemispheres contralateral to the deprived side were osmicated, sectioned at 40 microm and embedded in plastic for thin sectioning. Sterio's (J Microsc 134: 127-136, 1984) procedure combined with serial thin section analysis (Braendgaard and Gundersen, J Neurosci Meth 18: 39-78, 1986), was applied blindly to systematic random samples of neuropil in barrel hollows and septa. No significant difference in the numerical density, estimated total number, or in the proportion of perforated postsynaptic densities was observed. However, a significant decrease in the diameters of asymmetrical postsynaptic densities was observed in hollow (P < 0.05) and septal (P < 0.05) neuropil of deprived animals. These results demonstrate a significant morphological alteration in asymmetrical synapses of a type consistent with a reduction in synaptic activity consequent to sensory deprivation.
Somatosens Mot Res 2000
PMID:Effects of sensory deprivation on the development of asymmetrical synapses in mouse barrels. 1099 95

This study investigated intralimb coordination during walking in young and elderly women using the theoretical model of dynamical systems. 20 women, 10 Young (M age=24.6 yr., SD= 3.2 yr.) and 10 Elderly (M age=73.7 yr., SD=4.9 yr.), were videotaped during free speed gait and gait perturbed by an ankle weight. Two parameters, one describing the phasing relationship between segments (mean absolute relative phase) and the other the variability of this relationship (deviation in phase), were calculated from the kinematics. Two-way analysis of variance (age and weight) with repeated measures on weight indicated that during the braking period the weight increased the mean absolute relative phase between the shank and the thigh and decreased it between the foot and the shank. The Elderly women had significant smaller values for the mean absolute relative phase between the shank and the thigh during the braking period. For the same period, deviation in phase increased for the segmental 'relationship between the shank and the thigh. The findings suggest that changes in intralimb coordination take place with asymmetrical weighting and the aging process. These changes are most clearly present during the braking period.
Percept Mot Skills 2002 Feb
PMID:Comparison of gait patterns between young and elderly women: an examination of coordination. 1188 74

To examine whether ear dominance in a dichotic pitch-discrimination task is associated with asymmetrical activation of the two cortical hemispheres, ear dominance scores and electroencephalographic (EEG) laterality were correlated in two independent samples (ns=46 and 128). The results indicate that ear dominance can partly be attributed to a relatively stronger activation of the contralateral prefrontal cortex. The observed association may reflect the tendency to direct attention preferably to one ear.
Percept Mot Skills 2002 Apr
PMID:EEG correlates of behavioural laterality: ear dominance. 1202 24

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni- versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 3 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as they anticipate mirror manipulations of the object less. The frequency of bimanual reaching increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.
J Mot Behav 1997 Sep
PMID:Age Changes in Interlimb Coupling and the Development of Bimanual Coordination. 1245 79

The role of vision in the control of reaching and grasping was investigated by varying the available visual information. Adults (N = 7) reached in conditions that had full visual information, visual information about the target object but not the hand or surrounding environment, and no visual information. Four different object diameters were used. The results indicated that as visual information and object size decreased, subjects used longer movement times, had slower speeds, and more asymmetrical hand-speed profiles. Subjects matched grasp aperture to object diameter, but overcompensated with larger grasp apertures when visual information was reduced. Subjects also qualitatively differed in reach kinematics when challenged with reduced visual information or smaller object size. These results emphasize the importance of vision of the target in reaching and show that subjects do not simply scale a command template with task difficulty.
J Mot Behav 1996 Sep
PMID:Visual Information and Object Size in the Control of Reaching. 1252 2

This article contrasts the mechanical energy profiles of asymmetrical galloping with those of symmetrical running in adult humans. Seven female subjects were filmed while performing overground running and galloping at their preferred velocities. A previous study (Whitall & Caldwell, 1992) showed that kinematic differences between these gait modes included higher preferred velocity for running than galloping, with distinct differences in interlimb coordination but surprisingly similar intralimb patterns. Energetically, in the present study the whole body center of mass during galloping was found to behave much as it does in walking; kinetic and potential energy profiles were out of phase, as compared with running, which exhibited in-phase fluctuations of kinetic and potential energies. The primary reason for these center of mass differences was found in the energetics of the back leg of galloping, which demonstrated alterations in timing of its energy fluctuations and less energy generation than the front leg. Analysis of the power sources underlying the segmental energies during swing phase showed that the back leg's energy changes were accomplished mainly through reduced use of the hip muscles and less interlimb energy transfer. The back leg's energetics during swing also displayed a shift toward greater reliance on nonmuscular energy sources. A pattern of energy inflow during early swing and energy outflow during late swing was common to both running and galloping, although the galloping legs both demonstrated more abrupt transitions between these phases. The possibility is raised that the 67/33 interlimb phasing ratio used in galloping is selected to reduce mechanical energy variations of the total body center of mass. These data suggest that models of asymmetric gait in humans must account for more than merely phase alteration.
J Mot Behav 1995 Jun
PMID:An Energetic Comparison of Symmetrical and Asymmetrical Human Gait. 1273 23

Synchronous coordination between two body segments departs from phase locking at 0 or pi radians when the segments are asymmetrical. In models of coordination dynamics, this detuning is typically quantified by Deltaomega = (omega1 - omega2), where omega1 and omega2 are the uncoupled frequencies of the two segments. An experiment is reported in which the magnitude of Deltaomega not equal 0 was satisfied by different ratios Omega of omega1 and omega2. The degree of detuning was found to vary systematically with Omega and Deltaomega. This result corroborates previous research using the complementary manipulation of varying Deltaomega for a fixed Omega. A challenge for future dynamical modeling is identifying precisely how the detuning quantity incorporates both the absolute and relative differences in the. uncoupled segmental frequencies.
J Mot Behav 1996 Dec
PMID:An experimental note on defining frequency competition in intersegmental coordination dynamics. 1476 52

Most human gait forms assume symmetrical, alternating patterns of interlimb coordination (e.g., crawling, walking, running). Human galloping is a notable exception. In contrast to extensive information on galloping in animals, little is known about this gait in humans. Therefore, kinematic and topographical analyses of running and galloping were undertaken to investigate the manner in which the lower limbs are uncoupled to produce this asymmetrical gait. Seven adult females were filmed while running and galloping at their preferred speed. Analysis of the gaits revealed differences in the following: (a) preferred speed, (b) coupling between upper- and lower-limb girdles, and (c) point of foot fall (end-point trajectories). In contrast to clear differences in interlimb coordination, intralimb coordination was remarkably similar across gaits, although when galloping was adopted, the rear leg did show more variable change than the front leg.
J Mot Behav 1992 Dec
PMID:Coordination of symmetrical and asymmetrical human gait. 1476 63

The relation between progress in the control of posture (i.e., the achievement of self-sitting posture) and the developmental transition from two-handed to one-handed engagement in infant reaching was investigated. Two groups of 5- to 8-month-old infants, who were either able or yet unable to sit on their own, were videotaped while they reached for objects in four different posture conditions that provided varying amounts of body support. Videotapes of infant reaches were microanalyzed to determine the relative engagement of both hands during reaches. Results demonstrate the interaction between postural development and the morphology of infant reaching. Nonsitting infants displayed symmetrical and synergistic engagement of both arms and hands while reaching in all but the seated posture condition. Sitting infants, by contrast, showed asymmetrical and lateralized (one-handed) reaches in all posture conditions. Results also show that, aside from posture, the perceived spatial arrangement of the object display is a determinant of infant reaching. Combined, these results are discussed as evidence for the interaction between postural and perceptual development in the control of early eye-hand coordination.
J Mot Behav 1992 Jun
PMID:Self-sitting and reaching in 5- to 8-month-old infants: the impact of posture and its development on early eye-hand coordination. 1497 20


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