Free download program A Neurological Dissociation Between Perceiving Objects And Grasping Them Pdf9/23/2016 La agnosia visual se produce como consecuencia de una lesi. Free download as PDF File (.pdf), Text File (.txt) or read online for free. Scribd is the world's largest social reading and publishing site.
There were no differences between the hands with respect to these eliminated trials. Nevertheless, it is important to note that when these error trials were included in the analysis, the results were virtually identical to those described below. A neurological dissociation between perceiving. Grasping Occam’s Razor. Grasping of virtual objects in changed gravity. All participants in all groups started their movements within the 1,0. Moreover, there were no differences in movement time between the two hands. For the control trials in the Ponzo and Ebbinghaus experiments, no differences were found in grip aperture between the left and right hands of right- or left- handers, which in both groups were equally affected by real differences in the size of the target object. We compared the slopes of the MGA by subtracting the MGA of the small object from the MGA of the big object for the different hands and handedness groups. Ponzo illusion: left- handers, lh = 9. Ebbinghaus illusion: left- handers, lh = 5. A TWO- way ANOVA between group (right and left- handed participants) and hand (left and right) for the control trials in the Ponzo experiment showed no main effect of group F(1,1. F(1,1. 8) < 1 and no significant interaction between group and hand F(1,1. P = 0. 0. 8. Similarly, no main effect of group F(1,2. F(1,2. 4) < 1 and no significant interaction between group and hand F(1,2. Ebbinghaus experiment. In sharp contrast to the control data and regardless of handedness, grip aperture in the left hand was more affected by the illusory displays than grip apertures in the right hand (Fig. Thus when grasping with their left hand, both right- and left- handed participants opened their left hand wider for the target that was perceived as the bigger one than they did for the target that was perceived as the smaller one, even though both targets were identical in size. For the Ponzo illusion in the left- handed group, seven of nine participants showed a greater effect of the illusion in the left hand when compared with the right. In the right- handed group nine of 1. For the Ebbinghaus illusion, 1. FIG. 2. Effects of the Ponzo (A) and Ebbinghaus (B) illusions (in mm . When grasping with the left hand, maximum grip apertures were affected by the illusory context, resulting in larger apertures when the objects were perceived as big as compared with when the same objects were perceived as small. For the Ponzo illusion, a two- way ANOVA between group (right- and left- handers) and hand (right and left hand) revealed a main effect of hand . Similarly, for the Ebbinghaus illusion, a main effect of hand . We found that, in right- handers, both illusions had a strong effect on grip aperture in the left hand . Conversely, grasping with the right hand remained unaffected by the visual illusions . In the left- handers, both illusions again affected grasping with the left hand . The effect of the Ebbinghaus illusion on grasping with the right hand was not significantly different from zero . There was, however, a significant effect of the Ponzo illusion on the right hand in the left- handed participants . A two- way ANOVA with gender (female and male) and hand (left and right) was performed on the right- and left- handed participants. No main effect of gender or interaction was found to be significant in either handedness group (P > 0. Experiment 2: natural grasping. Although right- handers, as expected, showed a marked preference for their dominant hand when picking up objects (7. Furthermore, compared with right- handers, left- handers used their nondominant hand significantly more often to pick up objects in both ipsilateral and contralateral space (P < 0. Fig. Thus although left- handers do not use their right hand as often as right- handers, they nevertheless show evidence that their handedness does not extend to precision grasp. Instead the right hand/left hemisphere advantage for grasping attenuates their “left- handedness” and emerges when they have to pick up small objects quickly and accurately. FIG. 3. A and B: examples of the puzzle and LEGO. C: illustration of hand preference for grasping in ipsilateral and contralateral space (. Note that left- handers used their nondominant hand more frequently than right- handers.
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