Biomedical subjects

Sophie Vangheluwe

Publications and source records attributed to Sophie Vangheluwe.

7 recordsLinked to original sources

PubMed2005

Learning and transfer of bimanual multifrequency patterns: effector-independent and effector-specific levels of movement representation.

Current behavioural theories consider that during motor learning, an effector-independent memory representation of the acquired skill is built up. Using a transfer paradigm, we addressed the nature of the memory representation for a 2:1 multifrequency co-ordination task, requiring, for example, the left arm to cycle twice as fast as the right. After learning this 2:1 pattern, transfer to its converse pattern (i.e., the right arm cycles twice as fast as the left) revealed powerful evidence for negative transfer. The converse task arrangement revealed similar effects. These observations suggest a reconsideration of current viewpoints on movement representations, which emphasize effector independence. Based on the present findings, we propose a new model of motor memory, consisting of an abstract, effector-independent and an effector-specific layer. The abstract code is hypothesized to represent general spatiotemporal movement features, whereas the specific representation refers to effector-related movement commands. This concept is consistent with recent neuroscientific evidence in animal and human species, and invites a reconsideration of current behavioural theories of motor learning and memory.

Adult↗

PubMed2005

Learning and transfer of an ipsilateral coordination task: evidence for a dual-layer movement representation.

The present study addressed the nature of the memory representation for interlimb coordination tasks. For this purpose, the acquisition of a multifrequency (2:1) task with the ipsilateral limbs and transfer to the ipsilateral and contralateral body side was examined. In particular, subjects practiced a 2:1 coordination pattern whereby the right arm moved twice as fast as the right leg, or vice versa. Subsequently, they transferred the practiced 2:1 task to three different conditions: (1) the converse partner (i.e., the slow-moving limb had to move fast, and vice versa) at the ipsilateral body side, and (2) the identical and (3) converse 2:1 pattern at the contralateral body side. Findings revealed positive transfer of the identical and converse 2:1 pattern to the contralateral body side. However, no transfer of the learned pattern to its converse partner at the same body side was revealed. We propose a new memory representation model for coordination patterns, composed of an effector-independent and effector-specific component (dual-layer model). It is hypothesized that the general movement goal (i.e., moving one limb twice as fast as the other) constitutes the abstract, higher-level representation that may account for positive contralateral transfer. Conversely, the effector-specific component contains task-specific lower-level muscle synergies that are acquired through practice, prohibiting positive transfer when shifting task allocation within the same effectors. These findings are consistent with recent neuroscientific evidence for neuroplastic changes in distributed brain areas.

Adult↗

PubMed2004

Inter- and intralimb transfer of a bimanual task: generalisability of limb dissociation.

The present study examined whether the ability to dissociate bimanual limb movements following learning of a new coordination task (i.e. star-line drawing paradigm) can be generalised to different effector systems, as expressed by inter- and intralimb transfer. In Experiment 1, subjects practised the 'Line-Star' task (i.e. left arm traced the line/right arm traced the star) and then transferred this pattern to its symmetry partner: the 'Star-Line' task (left arm star/right arm line). In Experiment 2, intralimb transfer from the shoulder-elbow (proximal) to the wrist-finger joints (distal), and vice versa, was investigated. Results revealed positive interlimb transfer among symmetry partners of the star-line movement. Moreover, learning the star-line task spontaneously transferred from the trained to the untrained effector system whereby proximal to distal transfer was larger than vice versa. It is concluded that learning to spatially dissociate the movements of both limbs is generalisable to different motor conditions even though transfer to some conditions is suboptimal. It is hypothesised that the nature of the representation of the spatial interference task is largely effector independent.

Adult↗

PubMed2004

Bimanual coordination involving homologous and heterologous joint combinations: when lower stability is associated with higher flexibility.

Variability in behavior is often put in an unfavorable light as a marker of lack of skill. Here, we provide evidence that increased variability during preferred patterns of coordination is associated with higher flexibility in adopting new patterns. Twelve right-handed subjects performed cyclical bimanual flexion and extension patterns with four homologous and six heterologous joint combinations involving shoulder, elbow, wrist, and finger movements. Preferred (isofrequency) as well as less preferred (multifrequency) coordination patterns were studied. The findings revealed less accurate and less stable 1:1 coordination patterns during heterologous as compared to homologous limb segment combinations. Conversely, coordination patterns with a 2:1 frequency ratio were performed more accurately and more consistently during heterologous as compared to homologous conditions. Accordingly, a lower degree of coupling between effectors during performance of preferred coordination patterns was associated with more successful performance of less familiar patterns. This suggests that variability may promote the creative exploration of new performance modes.

Adult↗

PubMed2004

Bimanual directional interference: the effect of normal versus augmented visual information feedback on learning and transfer.

When performing movements with different spatial trajectories in both upper limbs simultaneously, patterns of interference emerge that can be overcome with practice. Even though studies on the role of augmented feedback in motor learning have been abundant, it still remains to be discovered how overcoming such specific patterns of spatial interference can be optimized by instructional intervention. In the present study, one group acquired a bimanual movement with normal vision, whereas a second group received augmented feedback of the obtained trajectories on a computer screen in real time. Findings revealed that, relative to normal vision, the augmented feedback hampered skill learning and transfer to different environmental conditions. These observations are discussed in view of the benefits and pitfalls of augmented feedback in relation to task context and instructional condition.

Adolescent↗

PubMed2003

Directional interference during bimanual coordination: is interlimb coupling mediated by afferent or efferent processes.

The role of afferent information in bimanual directional interference was studied by means of a modulation of the response-produced information in one of both limbs. In Experiment 1, visual information was either present, withdrawn, or shown with a directional transformation on a LCD screen. In Experiment 2, the technique of muscle tendon vibration was used to bias the kinesthetic afferent information associated with movement. The findings revealed strong evidence for directional interference between both limbs. Nevertheless, no evidence could be advanced that the observed interference from the right onto the left limb movement was modulated by manipulation of the afferent sources of information. It is concluded that directional interference primarily emerges at the efferent level of movement planning and organization.

Adult↗

PubMed2003

Bimanual training reduces spatial interference.

The authors investigated whether training can reduce bimanual directional interference by using a star-line drawing paradigm. Participants (N = 30) were required to perform rhythmical arm movements with identical temporal but differing directional demands. Moreover, the effectiveness of part-task training in which each movement was practiced in isolation was compared with that of whole-task training in which only combined movements were performed. Findings revealed that bimanual training substantially reduced spatial interference, but unimanual training did not. The authors therefore concluded that the spatial coupling of the limbs is not implemented in a rigid way; instead, the underlying neural correlate can undergo plastic changes induced by training. Moreover, the practical implication that emerged from the present study is that athletic, musical, or ergonomic skills that require a high degree of interlimb coordination are best served by whole-task practice.

Adult↗