Bilateral Hand Movements Research Articles

Effects of age and fine motor expertise on the bilateral deficit in force initiation

Performance of a task carried out with two hands separately is better than the performance of the same task done with both hands at the same time. This so-called bilateral deficit may be reduced or counteracted by long-term practice. Little is known about age-related changes. We examined age- and expertise-related differences in the bilateral deficit in force initiation. Participants performed static and dynamic force modulation tasks either with the right and left hand separately or both hands simultaneously. In order to examine age-related differences, we compared novices of fine motor control (service employees) from three age groups, covering the working age (young n = 13, early middle-aged n = 10 and late middle-aged n = 12). To assess the influence of expertise, we considered precision mechanics as experts in fine motor control. To ensure the acquisition of expertise, only early middle-aged (n = 10) and late middle-aged (n = 14) experts were recruited. Regardless of the task, bimanual force initiation was slower than unimanual force initiation. This bilateral deficit was (1) more pronounced in the static than in the dynamic task, (2) higher in early and late middle-aged than in younger novices, and (3) lower in experts as compared to novices. Based on our results, we assume both interhemispheric inhibition and division of attention to contribute to the bilateral deficit and the expertise- and age-related differences, respectively. The results are promising for the possibility to overcome constraints of bilateral hand movements by long-term practice.

Psychogenic Movement Disorder After H1N1 Influenza Vaccination

Psychogenic Movement Disorder After H1N1 Influenza Vaccination

Perceptual influence on bimanual coordination: an fMRI study

In bimanual coordination subjects typically show a spontaneous preference for movement symmetry. While there is experimental evidence for the principle of muscle homology, recent evidence suggested that bimanual coordination may be mediated as perceptual goals (Mechsner et al., 2001). To explore this controversy we performed a fMRI study in 11 healthy, right-handed subjects using bimanual index finger abductions and adductions in a congruous condition, i.e. both palms down, and incongruous conditions with either the left or right palm up. Our fMRI data showed a widespread bihemispheric network mediating proprioceptive coordination of the two hands with significant differences mainly for a perceptual dissociation: in the incongruous conditions with the one palm up there was a BOLD signal increase in a bilateral frontoparietal network involving the motor and premotor cortical areas, particularly in the right palm-up condition. These results accord with the notion that perceptual cues play an important role in the control of bilateral hand movements.

86. Perceptual dissociation of bimanual coordination: A fMRI study

In bimanual coordination tasks, subjects normally show a conspicuous advantage of symmetric movement patterns. This reliably becomes apparent when antiphase movements change into symmetry with increased movement velocities resulting from the coactivation of homologous muscles (e.g., Kelso et al., 1984; Johnson et al., 1998; Meesen et al., 2006). While these findings suggest that bimanual coordination is based on motor control, recent evidence suggested that bimanual coordination is governed by perceptual cues (Mechsner, Kerzel, Knoblich, and Prinz, 2001). To explore this controversy, we performed a fMRI study in 11 healthy, right-handed subjects using bimanual index finger abductions and adductions in a congruous condition, i.e. both palms down, and incongruous conditions with either the left or the right palm up. Our fMRI data showed a widespread bihemispheric network mediating bimanual coordination with significant differences (FDR < 0.05) for a perceptual dissociation: In the incongruous conditions with the one palm up there was a BOLD signal increase in a bilateral fronto-parietal network involving the motor and the premotor cortical areas, particularly in the right palm-up condition. These results accord with the notion of perceptual control of bilateral hand movements.

Dynamic intra- and interhemispheric interactions during unilateral and bilateral hand movements assessed with fMRI and DCM

Any motor action results from a dynamic interplay of various brain regions involved in different aspects of movement preparation and execution. Establishing a reliable model of how these areas interact is crucial for a better understanding of the mechanisms underlying motor function in both healthy subjects and patients. We used fMRI and dynamic causal modeling to reveal the specific excitatory and inhibitory influences within the human motor system for the generation of voluntary hand movements. We found an intrinsic balance of excitatory and inhibitory couplings among core motor regions within and across hemispheres. Neural coupling within this network was specifically modulated upon uni- and bimanual movements. During unimanual movements, connectivity towards the contralateral primary motor cortex was enhanced while neural coupling towards ipsilateral motor areas was reduced by both transcallosal inhibition and top-down modulation. Bimanual hand movements were associated with a symmetric facilitation of neural activity mediated by both increased intrahemispheric connectivity and enhanced transcallosal coupling of SMA and M1. The data suggest that especially the supplementary motor area represents a key structure promoting or suppressing activity in the cortical motor network driving uni- and bilateral hand movements. Our data demonstrate that fMRI in combination with DCM allows insights into intrinsic properties of the human motor system and task-dependent modulations thereof.

Perceptual Dissociation of Bimanual Coordination: A fMRI Study

In bimanual coordination tasks subjects normally show a conspicuous advantage of symmetric movement patterns. This reliably becomes apparent when antiphase movements change into symmetry with increased movement velocities resulting from coactivation of homologous muscles (e.g., Kelso et al. 1984; Johnson et al. 1998; Meesen et al., 2006). While these findings suggest that bimanual coordination is based on motor control, recent evidence suggested that bimanual coordination is governed by perceptual cues (Mechsner, Kerzel, Knoblich, & Prinz, 2001). To explore this controversy we performed a fMRI study in 11 healthy, right-handed subjects using bimanual index finger abductions and adductions in a congruous condition, i.e. both palms down, and incongruous conditions with either the left or right palm up. Our fMRI data showed a widespread bihemispheric network mediating bimanual coordination with significant differences (FDR <0.05) for a perceptual dissociation: In the incongruous conditions with the one palm up there was a BOLD-signal increase in a bilateral fronto-parietal network involving the motor and premotor cortical areas, particularly in the right palm-up condition. These results accord with the notion of perceptual control of bilateral hand movements.

Finger and Face Representations in the Ipsilateral Precentral Motor Areas in Humans

Several human neuroimaging studies have reported activity in the precentral gyrus (PcG) ipsilateral to the side of hand movements. This activity has been interpreted as the part of the primary motor cortex (M1) that controls bilateral or ipsilateral hand movements. To better understand hand ipsilateral-PcG activity, we performed a functional MRI experiment in eight healthy right-handed adults. Behavioral tasks involved hand or lower face movements on each side or motor imagery of the same movements. Consistent with the known M1 organization, the hand contralateral-PcG activity was centered at the "hand-knob" portion of the PcG; face contralateral-PcG activity was localized ventrolateral to it. Hand ipsilateral-PcG activity was identified in most subjects. However, converging results indicated that this ipsilateral PcG activity was situated in Brodmann's area 6 in both hemispheres. The hand ipsilateral-PcG zones were active not only during hand movements but also face movements. Moreover, the hand ipsilateral-PcG zones revealed substantial imagery-related activity, which also failed to differentiate the hand and face. Statistical analyses confirmed poor effector selectivity of the hand ipsilateral PcG activity during both movement and imagery tasks. From these results, we conclude that the hand ipsilateral-PcG activity in healthy adults probably corresponds to a part of the ventral premotor cortex. In contrast, available evidence suggests that M1 contributes to controlling the ipsilateral hand in children and patients after stroke recovery. It appears that within the human PcG, there are two parallel systems potentially capable of controlling ipsilateral hand movements: ventral premotor cortex and M1. These two systems may be differentially influenced by developmental or pathologic changes.

Supplementary Motor Area Cell Activity Related To Bilateral Hand Movements

Supplementary Motor Area Cell Activity Related To Bilateral Hand Movements

Nigrostriatal dopamine system and motor lateralization

The mechanism by which most people favor use of the right hand remains unknown. It has been proposed that asymmetries in the nigrostriatal dopamine system may be related to motor lateralization in humans. We explored this hypothesis in vivo by using [ 18F]fluorodopa positron emission tomography. Whereas the degree of right hand preference was found to correlate with left putamen dominance as assessed by asymmetry in fluorodopa uptake ( K i ), right caudate dominance was positively correlated with the level of performance during simultaneous bimanual movements in right-handed normal subjects. In addition, right-handed patients with Parkinson’s disease with higher right than left caudate K i performed much better in bimanual movement tests than those in whom the K i value of the left caudate was higher than that of the right. These findings support the notion that the nigrostriatal dopaminergic system may play a role in motor lateralization, and suggest a functional model for bimanual movements. We propose that the skill for performing simultaneous bilateral hand movements in right-handed subjects might depend upon both the activation (through the dominant left putamen circuitry) of the left supplementary motor area (SMA), and the inhibition (through the right caudate circuitry) of motor programs stored in the right SMA.

Mental representations of movements. Brain potentials associated with imagination of hand movements

The present study was designed in order to contribute towards the understanding of the physiology of motor imagery. DC potentials were recorded when subjects either imagined or executed a sequence of unilateral or bilateral hand movements. The sequence consisted of hand movements in 4 directions, forwards, backwards, to the right and to the left, and varied from trial to trial. The sequence had been cued by visual targets on a computer screen and had to be memorized before the trial was initiated. Changes of DC potentials between task execution and imagination were localized in central recordings (C3, Cz, C4) with larger amplitudes when executing the task than when imagining to do so. Stimulation of peripheral receptors associated with task execution or a different level of activation of the cortico-motoneural system could account for this finding. The main result of the present study was that with unilateral performance, the side of the performing hand (right, left) had localized effects in recordings over the sensorimotor hand area (C3, C4) which were qualitatively the same with imagination and execution and quantitatively similar (i.e., without significant difference). Performance of the right hand augmented negative DC potentials in C3, performance of the left hand augmented amplitudes in C4. This result is consistent with the assumption that the primary motor cortex is active with motor imagery. Finally, the question has been addressed whether motor imagery may involve the left hemisphere to a larger extent than the execution of the movement. It is shown that a particular contribution of the left hemisphere associated with motor imagery may only show up under strictly controlled conditions.

An output zone of the monkey primary motor cortex specialized for bilateral hand movement

We have identified a subregion in the monkey primary precentral motor cortex (MI) that is characterized by its relationship to bilateral or ipsilateral hand movements. The subregion is located between the digit and face representation areas. The majority of single cells in this portion of MI exhibit distinct activity before and during visually triggered key-press movements performed by means of ipsilateral or contralateral digit flexion. Intracortical microstimulation evoked responses of ipsilateral, in addition to contralateral, digit muscles.

Functional-activation asymmetries in normal humans studied with quantitative EEG (QEEG): First tests in the CNS Project

Work with behaviorally defined asymmetries such as relative ear advantages has led to the CNS Project, designed to apply noninvasive techniques such as psychophysics, EPs, QEEG, MEG, MRI, and PET to study human brain responses during functional activation. Preliminary results of a QEEG test series involving both auditory and hand-movement conditions indicate that QEEG power asymmetry patterns reflect at least two types of asymmetry organization: (1) “side of space,” e.g., right-hand movement elicits a power asymmetry favoring the left hemisphere, and v.v; and (2) asymmetries based on “higher-level” principles of organization, e.g., coordination during bilateral hand movement, or differential activation based on the physical characteristics of test sounds. As with behavioral patterns of relative ear advantages, QEEG shows individual differences in detail but group agreements in overall patterns of response. It is believed that this is the first report of QEEG used for studying functional activation in healthy human subjects, and illustrates its potential usefulness for studying human neurophysiology. [Work supported in part by AFOSR.]

Relation of neurons in the nonprimary motor cortex to bilateral hand movement.

In the primate cerebral cortex there are at least two somatotopically organized, nonprimary motor fields rostral to the primary motor area. To understand the functions of these multiple motor representations we have compared the neuronal activity in each of these fields while monkeys performed a trained motor task, using right, left or both hands. In the nonprimary motor cortex, activity in a number of neurons was related to the movement the animal chose and performed, whereas in the primary motor cortex, changes in the firing of most neurons were simply related to activity in the contralateral muscles. This result indicates that the nonprimary motor cortex is involved in higher-order coding of the laterality of the motor response, implying that it exerts its motor control function at a higher hierarchical level than its counterpart in the primary motor cortex.

Neuronal activity in the monkey supplementary motor and premotor cortex in relation to unilateral and bilateral hand movement

Neuronal activity in the monkey supplementary motor and premotor cortex in relation to unilateral and bilateral hand movement

PATTERNS OF PERCEPTUAL-MOTOR DYSFUNCTION IN CHILDREN: A FACTOR ANALYTIC STUDY.

Analysis of test scores made by 100 children with and 50 without suspected perceptual deficits lead to hypothesizing five syndromes characteristic of dysfunction: (a) developmental apraxia, distinguished by deficits in motor planning, tactile perception and finger identification; (b) tactile, kinesthetic and visual perceptual dysfunction in form and position in space; (c) tactile defensiveness, demonstrated by hyperactive-distractible behavior, faulty tactile perception and defensive responses to tactile stimuli; (d) deficit of integration of the two sides of the body, identified by difficulty in right-left discrimination, avoidance in crossing the mid-line, and incoordinate bilateral hand movements; (e) deficit of visual figure-ground discrimination.