Interlimb Transfer of Grasp Orientation is Asymmetrical (original) (raw)
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Hemispheric asymmetries in goal-directed hand movements are independent of hand preference
NeuroImage, 2012
Asymmetries in the kinematics and neural substrates of voluntary right and left eye-hand coordinated movements have been accredited to differential hemispheric specialization. An alternative explanation for between-hand movement differences could result from hand preference related effects. To test both assumptions, an experiment was conducted with left-and right-handers performing goal-directed movements with either hand paced by a metronome. Spatiotemporal accuracy was comparable between hands, whereas hand peak velocity was reached earlier when moving with the left compared to the right hand. The underlying brain activation patterns showed that both left-and right-handers activated more areas involved in visuomotor attention and saccadic control when using their left compared to the right hand. Altogether, these results confirm a unique perceptuomotor processing specialization of the left brain/right hand system that is independent of hand preference.
NeuroImage, 2011
When planning grasping actions, right-handers show left-lateralized responses in the anterior intraparietal sulcus (aIPS) and ventral premotor cortex (vPMC), two areas that are also implicated in sensorimotor control of grasp. We investigated whether a similar cerebral asymmetry is evident in strongly left-handed individuals. Fourteen participants were trained to grasp an object appearing in a variety of orientations with their left and right hands and with a novel mechanical tool (operated with either hand). BOLD fMRI data were then acquired while they decided prospectively whether an over-or under-hand grip would be most comfortable for grasping the same stimulus set while remaining still. Behavioral performances were equivalent to those recorded previously in right-handers and indicated reliance on effector-specific internal representations. In left-handers, however, grip selection decisions for both sides (left, right) and effectors (hand, tool) were associated with bilateral increases in activity within aIPS and vPMC. A direct comparison between left-and right-handers did reveal equivalent increases in left vPMC regardless of hand dominance. By contrast, aIPS and right vPMC activity were dependent on handedness, showing greater activity in the motor-dominant hemisphere. Though showing bilateral increases in both left-and right-handers, greater increases in the motor dominant hemisphere were also detected in the caudal IPS (cIPS), superior parietal lobule (SPL) and dorsal premotor cortex (dPMC). These findings provide further evidence that regions involved in the sensorimotor control of grasp also participate in grasp planning, and that for certain areas hand dominance is a predictor of the cerebral organization of motor cognitive functions.
Hand orientation for grasping depends on the direction of the reaching movement
Brain Research, 2000
The 3D orientation of the hand for grasping was studied while subjects reached for objects placed at several locations on a horizontal board, with movements starting from three initial hand positions. The hand movements were recorded with electromagnetic sensors giving 3D position and orientation information. The study focused on the azimuth, which is the projection of the hand orientation in a horizontal plane. The hand azimuth for grasping was linearly correlated with the direction of the reaching movement and not with the object direction in head-or shoulder-centered coordinates. This relationship was valid regardless of the initial hand position. A control experiment with constant movement direction showed a weaker, probably postural, effect of object direction in shoulder-centered coordinates. We suggest that hand orientation for grasping is mainly controlled in relation to the reaching movement direction.
The aim of this study was to characterize, using fMRI, the functional asymmetries of hand laterality task (HLT) in a sample of 295 participants balanced for handedness. During HLT, participants have to decide whether the displayed picture of a hand represent a right or a left hand. Pictures of hands' back view were presented for 150 ms in the right or left hemifield. At the whole hemisphere level, we evidenced that the laterality of the hand and of the hemifield in which the picture was displayed combined their effects on the hemispheric asymmetry in an additive way. We then identified a set of 17 functional homotopic regions of interest (hROIs) including premotor, motor, somatosensory and parietal regions, whose activity and asymmetry varied with the laterality of the presented hands. When the laterality of a right hand had to be evaluated, these areas showed stronger leftward asymmetry, the hROI located in the primary motor area showing a significant larger effect than all other hROIs. In addition a subset of six parietal regions involved in visuo-motor integration together with two postcentral areas showed a variation in asymmetry with hemifield of presentation. Finally, while handedness had no effect at the hemispheric level, two regions located in the parietal operculum and intraparietal sulcus exhibited larger leftward asymmetry with right handedness independently of the hand of presentation. The present results extend those of previous works in showing a shift of asymmetries during HLT according to the hand presented in sensorimotor areas including primary motor cortex. This shift was not affected by manual preference. They also demonstrate that the coordination of visual information and handedness identification of hands relied on the coexistence of contralateral motor and visual representations in the superior parietal lobe and the postcentral gyrus.
A bias in attention towards the dominant hand has been cited as a possible factor in the lateralisation of human bimanual coordination . A mirror was placed between the hands of 18 dextral participants performing rhythmic antiphase movements. This set-up gave the appearance of a reflected virtual hand (moving in time with the un-occluded hand), in the same spatial location as the occluded left or right hand. This asymmetrical conflict between vision and action examined whether the left hand would show higher levels of error when replaced by a virtual right hand than the converse condition. Higher levels of error were observed during performance of the anti-phase pattern overall in the conditions where the mirror was present (compared to control conditions without the mirror). However, this effect did not differ between hands. The implications for the mirror paradigm, possible explanations for the lack of asymmetry, and the consequences for the attentional bias hypothesis are discussed.
Journal of Neurophysiology, 2013
Coelho CJ, Przybyla A, Yadav V, Sainburg RL. Hemispheric differences in the control of limb dynamics: a link between arm performance asymmetries and arm selection patterns. Human handedness has been described and measured from two perspectives: handedness inventories rate hand preferences, whereas other tests examine motor performance asymmetries. These two measurement approaches reflect a major controversy in a literature that defines handedness as either a preference or an asymmetry in sensorimotor processing. Over the past decade, our laboratory has developed a model of handedness based on lateralization of neural processes. This model attributes distinct control processes to each hemisphere, which in turn lead to observable interlimb sensorimotor performance asymmetries. We now hypothesize that arm preference, or choice, may depend on the interaction between sensorimotor performance asymmetries and the given task. The purpose of this study is to examine whether arm selection is linked to interlimb performance asymmetries during reaching. Right-handed subjects made choice and nonchoice reaches to each of eight targets (d ϭ 3.5 cm) arranged radially (r ϭ 13 cm) around a midline starting position. We displaced each cursor (one associated with each hand) 30 cm to the midline start circle to ensure that there were no hemispace-related geometric, mechanical, or perceptual biases to use either arm for the two midline targets. The three targets on each side of the midline received mostly reaches from the ipsilateral arm, a tendency previously described as a "hemispace bias." However, the midline targets, which were equidistant from each hand, received more dominant arm reaches. Dominant arm hand paths to these targets were straighter and more accurately directed. Inverse dynamics analyses revealed a more proficient dominant arm strategy that exploited intersegmental dynamics to a greater extent than did the nondominant arm. These findings suggest that sensorimotor asymmetries in dynamic coordination might explain limb choices. We discuss the implications of these results for theories of action selection, models of handedness, and models of neural lateralization. neural lateralization; handedness; hand selection; motor control SOME OF THE EARLIEST RESEARCH on human brain lateralization emphasized a left hemisphere dominance for motor functions in most humans. For example, Broca (1865) described a left hemisphere specialization for processes that subserve speech and language, including speech motor control. Liepmann (1905) showed that left hemisphere damage tends to produce greater movement impairment than does right-hemisphere damage, defining apraxia as a key example of such impairment (see Allen 1983 and Geschwind 1975 for reviews). However, Sperry and Gazzaniga's seminal research on split-brain pa-
The relationship of handedness to a “lateralized” task
Neuropsychologia, 1978
There is a widespread belief that left-handers are less lateralized than right-handers, and consequently, are more likely to show deficits in performance on lateralized tasks. However, recent indications point to the possibility that it is the degree of handedness, regardless of direction, that accounts for differences in performance between handedness groups. We tested this notion through the use of a task developed by Nebes which involved matching of parts to wholes. Results indicated that performance on this lateralized task was indeed related to the degree of behaviorally-assessed preference and proficiency of handedness, and not to direction of hand preference.
Manual asymmetries in grasp pre-shaping and transport–grasp coordination
Experimental Brain Research, 2008
Few studies have directly compared the visuomotor transformation of grasp pre-shaping or transportgrasp coordination of reach-to-grasp movements between the two hands. Our objective was to determine if there are manual asymmetries in right-handed adults as a foundation to investigate hemispheric specialization in individuals post-stroke. Twelve non-disabled right-handed adults performed rapid reach-to-grasp movements to cylinders of three sizes as vision of the arm and hand was partially occluded. We reasoned that the hand system (left or right) that is superior in anticipatory planning of aperture scaling and movement preparation would be more likely to exhibit early grasp pre-shaping under this experimental manipulation. Movement time, hand path, transport velocity, and aperture were derived from 3D electromagnetic sensor data. The visuo-motor transformation of object sizes into an action of aperture pre-shaping was quantiWed using the correlations between initial aperture velocity and object diameter, and peak aperture and object diameter. Coordination between hand transport and aperture grasping was quanti-Wed using the cross-correlation between transport velocity and aperture size. Peak aperture and object diameter were strongly correlated for both hands. However, early aperture velocity and object diameter were correlated only for lefthand movements. Cross-correlation analyses revealed a strong association between transport velocity and aperture only for right-hand movements. Together, these results suggest earlier anticipatory control for the left hand in the visuo-motor transformation of grasp pre-shaping and a stronger transport-grasp linkage for the right hand. Further, initial aperture velocity was a more sensitive measure of these manual asymmetries than peak aperture. Our Wndings compliment the specialization previously observed for pointing movements of the dominant and non-dominant hemispheric/limb system and the coordinated control of complex movements and visuo-spatial components, respectively.
Orientation of the opposition axis in mentally simulated grasping
Experimental Brain Research, 2001
Five normal subjects were tested in a simulated grasping task. A cylindrical container filled with water was placed on the center of a horizontal monitor screen. Subjects used a precision grip formed by the thumb and index finger of their right hand. After a preliminary run during which the container was present, it was replaced by an image of the upper surface of the cylinder appearing on the horizontal computer screen on which the real cylinder was placed during the preliminary run. In each trial the image was marked with two contact points which defined an opposition axis in various orientations with respect to the frontal plane. The subjects' task consisted, once shown a stimulus, of judging as quickly as possible whether the previously experienced action of grasping the container full of water and pouring the water out would be easy, difficult or impossible with the fingers placed according to the opposition axis indicated on the circle. Response times were found to be longer for the grasps judged to be more difficult due to the orientation and position of the opposition axis. In a control experiment, three subjects actually performed the grasps with different orientations and positions of the opposition axis. The effects of these parameters on response time followed the same trends as during simulated movements. This result shows that simulated hand movements take into account the same biomechanical limitations as actually performed movements.