Individuated finger movements of rhesus monkeys: a means of quantifying the independence of the digits

1991 ◽  
Vol 65 (6) ◽  
pp. 1381-1391 ◽  
Author(s):  
M. H. Schieber

1. Two rhesus monkeys were trained to perform flexion and extension movements of each digit of the right hand and of the wrist. Movements of all five digits and the wrist were monitored simultaneously. During each instructed movement, the instructed digit (or wrist) had the greatest excursion; other, noninstructed digits moved to varying degrees. 2. To assess the degree of independence of the different digits during these movements, I plotted, as a function of the instructed digit's position, the position of each noninstructed digit. The resulting trajectories typically were linear, with consistent slopes from trial to trial. 3. The slopes of these noninstructed digit versus instructed digit trajectories were used to calculate an individuation index for each instructed movement and a stationarity index for each digit. These indexes quantified two different aspects of independence. The individuation index reflects the degree to which other digits remained still during instructed movement of a given digit. The stationarity index reflects the degree to which a given digit remained still whenever it was a noninstructed digit. 4. In accordance with casual observation, thumb flexion and wrist flexion and extension consistently had both high individuation and stationarity and therefore can be said to be independent of the fingers. Although the same cannot be said of the other fingers, the present analysis provides a means of quantifying the degree of independence of these digits as well. 5. Factors are discussed that might contribute to the motion of noninstructed digits and to the trajectory linearity.

2018 ◽  
Vol 120 (2) ◽  
pp. 729-740 ◽  
Author(s):  
Elizabeth J. Woytowicz ◽  
Kelly P. Westlake ◽  
Jill Whitall ◽  
Robert L. Sainburg

Two contrasting views of handedness can be described as 1) complementary dominance, in which each hemisphere is specialized for different aspects of motor control, and 2) global dominance, in which the hemisphere contralateral to the dominant arm is specialized for all aspects of motor control. The present study sought to determine which motor lateralization hypothesis best predicts motor performance during common bilateral task of stabilizing an object (e.g., bread) with one hand while applying forces to the object (e.g., slicing) using the other hand. We designed an experimental equivalent of this task, performed in a virtual environment with the unseen arms supported by frictionless air-sleds. The hands were connected by a spring, and the task was to maintain the position of one hand while moving the other hand to a target. Thus the reaching hand was required to take account of the spring load to make smooth and accurate trajectories, while the stabilizer hand was required to impede the spring load to keep a constant position. Right-handed subjects performed two task sessions (right-hand reach and left-hand stabilize; left-hand reach and right-hand stabilize) with the order of the sessions counterbalanced between groups. Our results indicate a hand by task-component interaction such that the right hand showed straighter reaching performance whereas the left hand showed more stable holding performance. These findings provide support for the complementary dominance hypothesis and suggest that the specializations of each cerebral hemisphere for impedance and dynamic control mechanisms are expressed during bilateral interactive tasks. NEW & NOTEWORTHY We provide evidence for interlimb differences in bilateral coordination of reaching and stabilizing functions, demonstrating an advantage for the dominant and nondominant arms for distinct features of control. These results provide the first evidence for complementary specializations of each limb-hemisphere system for different aspects of control within the context of a complementary bilateral task.


Tempo ◽  
1991 ◽  
pp. 18-23 ◽  
Author(s):  
Stephen Montague

In the early 1920s and 30s a strange electronic instrument found its way from Russia into some of the more fashionable ballrooms, night clubs, and concert halls in Europe and America. This exotic new invention, called the ‘theremin’ or ‘thereminvox’, caused a considerable stir. Part of the interest was its unusual sound (like a musical saw mated with a light soprano), but its most dramatic feature was that the performer never actually touched the instrument. He or she simply waved graceful hands near the two antennae (one set vertically, the other looped horizontally) to coax out seamless, melifluous melodies. The proximity of the right hand to the vertical antenna changed the ultrasonic electromagnetic field, thus changing the pitch over about a six-octave range. The left hand (or sometimes a foot pedal) controlled the volume. By gently shaking the right hand at the antenna a vibrato could be achieved, giving performances a little more musical (not to mention choreographic) interest. Fashionable women dressed in long gowns seemed to be favourite photographic subjects of the period as performers, as well as the inventor himself, poised ‘playing the rods’ in full dress tails, arms outstretched like a great conductor–or perhaps sorcerer.


Author(s):  
K. B. E. E. Eimeleus

This chapter looks at turns on the move with the right or left shoulder aligned with the corresponding ski. It distinguishes three important techniques that have gained currency in the world of sport. One of them pertains only to running skis while the other two require mountain skis with stable bindings. The first is the method for turning in place, used while descending from a mountain or over flat terrain on running skis, or on any skis that lack a stable binding and have a posterior center of balance. The next is the Christiania turn, which is carried out on the inner ski, that is, on the right ski when the turn is done to the right-hand side. Finally, the Telemark turn allows a skier to make a sudden stop as they are descending.


1989 ◽  
Vol 6 (3) ◽  
pp. 299-314 ◽  
Author(s):  
Yves Guiard

An experiment compared the ability of classical pianists to sing, during keyboard performance, the right- and the left-hand part of the score being played. Upon instructions requiring them to "sing" one or the other voice of the score, the subjects spontaneously chose to sing and name the notes simultaneously, in keeping with the French traditional way of reading music, thus producing a two- dimensional tonal and verbal vocal act in response to each visual stimulus. Singing the right-hand part of the music, whether in unison with or in place of the right hand, while concurrently playing the left-hand part was judged easy by all subjects, and performance, typically, was correct in all respects. The other task, consisting of singing the left-hand part of the music, was judged more difficult by all subjects, and performance, more often than not, was poor. Careful inspection of the many errors that were recorded in the latter task revealed a few clear-cut regularities. Failures were vocal, but not manual. More specifically, vocal failures took place on the tonal dimension of the vocal response, but not on its verbal dimension: The song, but not the naming of the notes, was prone to fail, with either a loss of the pitch, or a systematic trend toward singing unduly—albeit accurately—the notes of the right-hand part. A number of subjects were found to display this intriguing tonal/verbal dissociation—naming a note at a pitch corresponding to another note—in a continuous regime. It is emphasized that this phenomenon amounts to the spontaneous production of musical events that belong to the Stroop category.


2011 ◽  
Vol 28 (5) ◽  
pp. 491-503 ◽  
Author(s):  
Shinya Fujii ◽  
Masaya Hirashima ◽  
Kazutoshi Kudo ◽  
Tatsuyuki Ohtsuki ◽  
Yoshihiko Nakamura ◽  
...  

the present study examined the synchronization error (SE) of drum kit playing by professional drummers with an auditory metronome, focusing on the effects of motor effectors and tempi. Fifteen professional drummers attempted to synchronize a basic drumming pattern with a metronome as precisely as possible at tempi of 60, 120, and 200 beats per minute (bpm). In the 60 and 120 bpm conditions, the right hand (high-hat cymbals) showed small mean SE (∼2 ms), whereas the left hand (snare drum) and right foot (bass drum) preceded the metronome by about 10 ms. In the 200 bpm condition, the right hand was delayed by about 10 ms relative to the metronome, whereas the left hand and right foot showed small SE (∼1 ms). The absolute values of SE were smaller than those reported in previous tapping studies. In addition, the time series of SE were significantly correlated across the motor effectors, suggesting that each limb synchronized in relation to the other limbs rather than independently with the metronome.


1936 ◽  
Vol 56 (2) ◽  
pp. 235-236
Author(s):  
A. D. Trendall

Of the recent acquisitions to the Classical Collection of the Otago Museum (Dunedin, New Zealand) the most noteworthy is a particularly fine Attic white ground lekythos of about the middle of the fifth century (Plate XIV). It stands 38 cm. high and is in an excellent state of preservation, having been most carefully repaired with a minimum of repainting, which has affected only the breast of the woman, the right hand of the warrior, and some details of the small figure on top of the stele.The design represents a stele scene of the sort so popular with lekythos artists of this period. To the left stands a woman wearing a sleeved chiton, so thin that it clearly allows her bowed legs to be seen through it; with her left hand she points downward to the base of the stele, which is adorned with a fillet and a wreath. On the other side stands a hoplite with his shield and spear;


Perception ◽  
2005 ◽  
Vol 34 (9) ◽  
pp. 1153-1155 ◽  
Author(s):  
Eric Lewin Altschuler

I have noticed a striking effect that vision can have on movement: when a person makes circular motions with both hands, clockwise with the left hand, counterclockwise with the right hand, while watching the reflection of one hand in a parasagitally placed mirror, if one arm makes a vertical excursion, the other arm tends to make the same vertical excursion, but not typically if the excursing arm is viewed in plain vision. This observation may help in understanding how visual feedback via a mirror may be beneficial for rehabilitation of some patients with movement deficits secondary to certain neurologic conditions, and illustrates that the traditional division of neural processes into sensory input and motor output is somewhat arbitrary.


Author(s):  
Christopher Berg

This chapter offers material for arpeggio study suitable for beginners through advanced players. Arpeggio textures are one of the most commonly used textures in music for the classical guitar, and the number of arpeggio études in the literature reflects this. Material begins with simple right-hand arpeggio patterns that make use of sympathetic movement of the fingers between thumb strokes (that is, the right-hand fingers flex together or in sequence, and no finger moves in the opposite direction during the arpeggio pattern) and continues through increasingly complex patterns involving opposed motion among the fingers (that is, right-hand fingers are used more than once in a pattern between thumb strokes), sometimes in combination with an independent voice played by the thumb. The cultivated study of sympathetic and opposed motion will help guitarists design more fluid and coordinated finger movements to enhance their arpeggio technique.


2000 ◽  
Vol 16 (4) ◽  
pp. 379-391 ◽  
Author(s):  
Sheng Li ◽  
Frederic Danion ◽  
Mark L. Latash ◽  
Zong-Ming Li ◽  
Vladimir M. Zatsiorsky

One purpose of the present study was to compare indices of finger coordination during force production by the fingers of the right hand and of the left hand. The other purpose was to study the relation between the phenomena of force deficit during multifinger one-hand tasks and of bilateral force deficit during two-hand tasks. Thirteen healthy right-handed subjects performed maximal voluntary force production tasks with different finger combinations involving fingers of one hand or of both hands together. Fingers of the left hand demonstrated lower peak forces, higher indices of finger enslaving, and similar indices of force deficit. Significant bilateral effects during force production by fingers of both hands acting in parallel were seen only during tasks involving different fingers or finger groups in the two hands (asymmetrical tasks). The bilateral deficit effects were more pronounced in the hand whose fingers generated higher forces. These findings suggest a generalization of an earlier introduced principle of minimization of secondary moments. They also may be interpreted as suggesting that bilateral force deficit is task-specific and may reflect certain optimization principles.


1879 ◽  
Vol 24 (108) ◽  
pp. 617-622
Author(s):  
Henry Clarke

Elizabeth W., æt. 35, married, three children, one living, two dead, one at four months old, from “fits,” the other at six months, from “water on the brain.” No miscarriages. Patient states that she never had a day's illness in her life. She was committed to prison Dec. 31, 1877, and up till the commencement of her present illness, has been quite well, except that for the last few weeks she has suffered from a constant pain at the back of her neck. On February 20th, 1878, about 11.30 a.m., while sitting in her cell picking oakum, she felt a sudden numbness in the right hand and arm, and almost directly afterwards found that she was unable to speak, or move the right arm or leg. There was no loss of consciousness. She was seen within ten minutes of the attack, and had then partly recovered her speech, but still spoke thickly and indistinctly. Had regained power in the leg, but only partially in the arm. Sent to hospital.


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