Synergistic finger movements in a skilled motor task

Fish, Judith; Soechting, John F.

doi:10.1007/bf00231666

Cited by 41 publications

(29 citation statements)

References 8 publications

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“…Other observations reinforce the conclusions we reached from our study of typing, namely, the two hands generally move independently of each other Fish and Soechting 1992). While there were many instances in which the fingers of each hand depressed keys virtually simultaneously, there were also instances in which there was definite asynchrony in the times of key-on for notes that were intended (by the composer) to be synchronous.…”

Section: Control Of Bilateral Timing Of Keypressessupporting

confidence: 78%

Anticipatory and sequential motor control in piano playing

1997

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Pianists were asked to play short excerpts from several pieces on an electronic keyboard. In each piece, there were two phrases whose first few notes were played identically with the right hand. Thereafter, the two phrases were played differently. The aim of the investigation was to ascertain whether or not hand and finger kinematics diverged prior to the depression of the last common note. Such a divergence would imply an anticipatory modification of sequential movements of the hand, akin to the phenomenon of coarticulation in speech. The lack of such a divergence would imply a strictly serial organization of movement sequences with one hand, as was found previously to be the case for typing. The time at which each key was depressed and released and the speed with which the key was depressed was recorded via a MIDI interface to a laboratory computer. The motion of the right wrist and of the fingers of the right hand was recorded optoelectronically. Piano playing can invoke anticipatory modifications of hand and finger kinematics. The time at which two patterns of movements diverged varied considerably from piece to piece. Playing an ascending scale with the requirement of a "thumb-under" maneuver could evoke an anticipatory modification as much as 500 ms in advance of the last common note. In another piece, keypresses appeared to be executed in a strict serial ordering and a third piece gave results intermediate between these two extremes. We interpret the results to suggest that a strict serial execution of a movement sequence is favored as long as this is compatible with the demands of the task.

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Section: Control Of Bilateral Timing Of Keypressessupporting

confidence: 78%

Anticipatory and sequential motor control in piano playing

1997

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“…Although it is generally assumed that fingers move independently, it has been shown that humans hardly ever move one finger alone (Fish and Soechting 1992;Soechting and Flanders 1992;Engel et al 1997). Co-activation in muscles not related to the movement has, in part, a central cortical origin (HagerRoss and Schieber 2000;Slobounov et al 2002), which we refer to as unintentional co-activation.…”

Section: Introductionmentioning

confidence: 93%

Short-latency afferent inhibition during selective finger movement

et al. 2005

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During individual finger movement, two opposite phenomena occur at the level of the central nervous system that could affect other intrinsic hand muscle representations, unintentional co-activation, and surround inhibition (SI). At rest, excitability in the motor cortex (M1) is inhibited at about 20 ms after electric stimulation of a peripheral nerve [short-latency afferent inhibition (SAI)]. We sought to determine whether SAI changes during selective index finger movement. Effects were measured by the response to transcranial magnetic stimulation in two functionally distinct target muscles of the hand [abductor digiti minimi muscle (ADM), first dorsal interosseus muscle (FDI)]. An increase in SAI in the ADM during index finger movement compared to at rest could help explain the genesis of SI. Electrical stimulation was applied to either the little finger (homotopic for ADM, heterotopic for FDI) or the index finger (heterotopic for ADM, homotopic for FDI). During index finger movement, homotopic SAI was present only in the ADM, and the effect of peripheral stimulation was greater when there was less co-activation. Heterotopic SAI found at rest disappeared with movement. We conclude that during movement, homotopic SAI on the muscle in the surround of the intended movement may contribute to SI.

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“…Hand motion studies involving simple activities such as reach-to-grasp (Santello et al, , 2002Mason et al, 2001;Braido and Zhang, 2004), and skilled activities such as typing (Fish and Soechting, 1992;Soechting and Flanders, 1997) or finger-spelling (Jerde et al, 2003;Weiss and Flanders, 2004), reveal that a small dimensional space accounts for a large fraction of the postural variance observed during these tasks. Even individuated finger movements, which are the hallmark of any skilled activity, occur with synergistic couplings with adjacent digits (Schieber, 1995;Hager-Ross and Schieber, 2000).…”

Section: Introductionmentioning

confidence: 99%

Multidigit Movement Synergies of the Human Hand in an Unconstrained Haptic Exploration Task

Thakur

Bastian

Hsiao³

2008

J. Neurosci.

160

147

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Although the human hand has a complex structure with many individual degrees of freedom, joint movements are correlated. Studies involving simple tasks (grasping) or skilled tasks (typing or finger spelling) have shown that a small number of combined joint motions (i.e., synergies) can account for most of the variance in observed hand postures. However, those paradigms evoked a limited set of hand postures and as such the reported correlation patterns of joint motions may be task-specific. Here, we used an unconstrained haptic exploration task to evoke a set of hand postures that is representative of most naturalistic postures during object manipulation. Principal component analysis on this set revealed that the first seven principal components capture Ͼ90% of the observed variance in hand postures. Further, we identified nine eigenvectors (or synergies) that are remarkably similar across multiple subjects and across manipulations of different sets of objects within a subject. We then determined that these synergies are used broadly by showing that they account for the changes in hand postures during other tasks. These include hand motions such as reach and grasp of objects that vary in width, curvature and angle, and skilled motions such as precision pinch. Our results demonstrate that the synergies reported here generalize across tasks, and suggest that they represent basic building blocks underlying natural human hand motions.

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Synergistic finger movements in a skilled motor task

Cited by 41 publications

References 8 publications

Anticipatory and sequential motor control in piano playing

Anticipatory and sequential motor control in piano playing

Short-latency afferent inhibition during selective finger movement

Multidigit Movement Synergies of the Human Hand in an Unconstrained Haptic Exploration Task

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