scholarly journals Neuromuscular Fatigue in Unimanual Handgrip Does Not Completely Affect Simultaneous Bimanual Handgrip

2021 ◽  
Vol 15 ◽  
Author(s):  
Mikito Hikosaka ◽  
Yu Aramaki
Keyword(s):  
Random Order ◽  
Neuromuscular Fatigue ◽  
Motor Output ◽  
Force Generation ◽  
Left Hand ◽  
Bimanual Movements ◽  
Right Hand ◽  
The Right ◽  
Specific Part ◽  
Generating System

Simultaneous bimanual movements are not merely the sum of two unimanual movements. Here, we considered the unimanual/bimanual motor system as comprising three components: unimanual-specific, bimanual-specific, and overlapping (mobilized during both unimanual and bimanual movements). If the force-generating system controlling the same limb differs between unimanual and bimanual movements, unimanual exercise would be expected to fatigue the unimanual-specific and overlapping parts in the force-generating system but not the bimanual-specific part. Therefore, we predicted that the decrease in bimanual force generation induced by unimanual neuromuscular fatigue would be smaller than the decrease in unimanual force generation. Sixteen healthy right-handed adults performed unimanual and bimanual maximal handgrip measurements before and after a submaximal fatiguing handgrip task. In the fatigue task, participants were instructed to maintain unimanual handgrip force at 50% of their maximal handgrip force until the time to task failure. Each participant performed this task in a left-hand fatigue (LF) condition and a right-hand fatigue (RF) condition, in a random order. Although the degree of neuromuscular fatigue was comparable in both conditions, as expected, the decrease in bimanual right handgrip force was significantly smaller than those during unimanual right performance in the RF condition, but not in the LF condition. These results indicate that for the right-hand, neuromuscular fatigue in unimanual handgrip does not completely affect simultaneous bimanual handgrip. Regarding the underlying mechanisms, we propose that although neuromuscular fatigue caused by unimanual handgrip reduces the motor output of unimanual-specific and overlapping parts in the force-generating system, when simultaneous bimanual handgrip is performed, the overlapping part (which is partially fatigued) and the bimanual-specific part (which is not yet fatigued) generate motor output, thus decreasing the force reduction.

Cross talk in implicit assignment of error information during bimanual visuomotor learning

2011 ◽  
Vol 106 (3) ◽  
pp. 1218-1226 ◽  
Author(s):  
Shoko Kasuga ◽  
Daichi Nozaki
Keyword(s):  
Cross Talk ◽  
Training Session ◽  
Bimanual Movement ◽  
Credit Assignment ◽  
Left Hand ◽  
Bimanual Movements ◽  
Right Hand ◽  
Movement Error ◽  
Cursor Position ◽  
The Right

When a neural movement controller, called an “internal model,” is adapted to a novel environment, the movement error needs to be appropriately associated with the controller. However, their association is not necessarily guaranteed for bimanual movements in which two controllers—one for each hand—result in two movement errors. Considering the implicit nature of the adaptation process, the movement error of one hand can be erroneously associated with the controller of the other hand. Here, we investigated this credit-assignment problem in bimanual movement by having participants perform bimanual, symmetric back-and-forth movements while displaying the position of the right hand only with a cursor. In the training session, the cursor position was gradually rotated clockwise, such that the participants were unaware of the rotation. The movement of the right hand gradually rotated counterclockwise as a consequence of adaptation. Although the participants knew that the cursor reflected the movement of the right hand, such gradual adaptation was also observed for the invisible left hand, especially when the cursor was presented on the left side of the display. Thus the movement error of the right hand was implicitly assigned to the left-hand controller. Such cross talk in credit assignment might influence motor adaptation performance, even when two cursors are presented; the adaptation was impaired when the rotations imposed on the cursors were opposite compared with when they were in the same direction. These results indicate the inherent presence of cross talk in the process of associating action with consequence in bimanual movement.

Interaction of Vision and Movement via a Mirror

Perception ◽  
2005 ◽  
Vol 34 (9) ◽  
pp. 1153-1155 ◽  
Author(s):  
Eric Lewin Altschuler
Keyword(s):  
Visual Feedback ◽  
Sensory Input ◽  
Motor Output ◽  
The Other ◽  
Left Hand ◽  
Right Hand ◽  
Neural Processes ◽  
The Right ◽  
Striking Effect

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.

scholarly journals Visuomotor information drives interference between the hands more than dynamic motor information during bimanual reaching

2021 ◽  
Author(s):  
Phillip C Desrochers ◽  
Alexander T Brunfeldt ◽  
Florian A Kagerer
Keyword(s):  
Brain Regions ◽  
Left Hand ◽  
Bimanual Movements ◽  
Right Hand ◽  
Contralateral Hand ◽  
Motor Information ◽  
The Right ◽  
Neural Crosstalk ◽  
Bimanual Reaching ◽  
Dynamic Perturbation

During complex bimanual movements, interference can occur in the form of one hand influencing the action of the contralateral hand. Interference likely results from conflicting sensorimotor information shared between brain regions controlling hand movements via neural crosstalk. However, how visual and force-related feedback processes interact with each other during bimanual reaching is not well understood. In this study, four groups experienced either a visuomotor perturbation, dynamic perturbation, combined visuomotor and dynamic perturbation, or no perturbation in their right hand during bimanual reaches, with each hand controlling its own cursor. The left hand was examined for interference as a consequence of the right-hand perturbation. The results indicated that the visuomotor and combined perturbations showed greater interference in the left hand than the dynamic perturbation, but that the combined and visuomotor perturbations were equivalent. This suggests that dynamic sensorimotor and visuomotor processes do not interact between hemisphere-hand systems, and that primarily visuomotor processes lead to interference between the hands.

Editorial Note

1946 ◽  
Vol 11 (1) ◽  
pp. 2-2
Keyword(s):  
Editorial Note ◽  
Speech Sounds ◽  
Left Hand ◽  
Hand Column ◽  
Right Hand ◽  
Infant Speech ◽  
The Right

In the article “Infant Speech Sounds and Intelligence” by Orvis C. Irwin and Han Piao Chen, in the December 1945 issue of the Journal, the paragraph which begins at the bottom of the left hand column on page 295 should have been placed immediately below the first paragraph at the top of the right hand column on page 296. To the authors we express our sincere apologies.

scholarly journals Digit Variability in Carotenoid Scores Obtained with the Veggie Meter: A Pilot Study (P02-001-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Velarie Ansu ◽  
Stephanie Dickinson ◽  
Alyce Fly
Keyword(s):  
Indiana University ◽  
Left Hand ◽  
Funding Sources ◽  
Right Hand ◽  
Period Data ◽  
The Mean ◽  
The Right ◽  
Post Hoc ◽  
Main Effects ◽  
Mean Square Errors

Abstract Objectives To determine which digit and hand have the highest and lowest skin carotenoid scores, to compare inter-and-intra-hand variability of digits, and to determine if results are consistent with another subject. Methods Two subjects’ first(F1), second(F2), third(F3) and fifth(F5) digits on both hands were measured for skin carotenoids with a Veggie Meter, for 3 times on each of 18 days over a 37-day period. Data were subjected to ANOVA in a factorial treatment design to determine main effects for hand (2 levels), digits (4), and days (18) along with interactions. Differences between digits were determined by Tukey's post hoc test. Results There were significant hand x digit, hand x day, digit x day, and hand x digit x day interactions and significant simple main effects for hand, digit, and day (all P < 0.001). Mean square errors were 143.67 and 195.62 for subject A and B, respectively, which were smaller than mean squares for all main effects and interactions. The mean scores ± SD for F1, F2, F3, and F5 digits for the right vs left hands for subject A were F1:357.13 ± 45.97 vs 363.74 ± 46.94, F2:403.17 ± 44.77 vs. 353.20 ± 44.13, F3:406.76 ± 43.10 vs. 357.11 ± 45.13, and F5:374.95 ± 53.00 vs. 377.90 ± 47.38. For subject B, the mean scores ± SD for digits for the right vs left hands were F1:294.72 ± 61.63 vs 280.71 ± 52.48, F2:285.85 ± 66.92 vs 252.67 ± 67.56, F3:268.56 ± 57.03 vs 283.22 ± 45.87, and F5:288.18 ± 34.46 vs 307.54 ± 40.04. The digits on the right hand of both subjects had higher carotenoid scores than those on the left hands, even though subjects had different dominant hands. Subject A had higher skin carotenoid scores on the F3 and F2 digits for the right hand and F5 on the left hand. Subject B had higher skin carotenoid scores on F5 (right) and F1 (left) digits. Conclusions The variability due to hand, digit, and day were all greater than that of the 3 replicates within the digit-day for both volunteers. This indicates that data were not completely random across the readings when remeasuring the same finger. Different fingers displayed higher carotenoid scores for each volunteer. There is a need to conduct a larger study with more subjects and a range of skin tones to determine whether the reliability of measurements among digits of both hands is similar across the population. Funding Sources Indiana University.

The State Policy towards the Homeless in Moldova between the ‘Left Hand’ and the ‘Right Hand’. The Case of Chișinău Shelter

Südosteuropa ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 175-195
Author(s):  
Petru Negură
Keyword(s):  
Homeless People ◽  
Severe Disabilities ◽  
The State ◽  
Small Scale ◽  
Left Hand ◽  
Right Hand ◽  
Binary Approach ◽  
The One ◽  
The Right ◽  
Depth Interviews

Abstract The Centre for the Homeless in Chișinău embodies on a small scale the recent evolution of state policies towards the homeless in Moldova (a post-Soviet state). This institution applies the binary approach of the state, namely the ‘left hand’ and the ‘right hand’, towards marginalised people. On the one hand, the institution provides accommodation, food, and primary social, legal assistance and medical care. On the other hand, the Shelter personnel impose a series of disciplinary constraints over the users. The Shelter also operates a differentiation of the users according to two categories: the ‘recoverable’ and those deemed ‘irrecoverable’ (persons with severe disabilities, people with addictions). The personnel representing the ‘left hand’ (or ‘soft-line’) regularly negotiate with the employees representing the ‘right hand’ (‘hard-line’) of the institution to promote a milder and a more humanistic approach towards the users. This article relies on multi-method research including descriptive statistical analysis with biographical records of 810 subjects, a thematic analysis of in-depth interviews with homeless people (N = 65), people at risk of homelessness (N = 5), professionals (N = 20) and one ethnography of the Shelter.

scholarly journals The Left Hand Doesn’t Know What the Right Hand Is Doing—or Does It?

Cell Reports ◽  
2016 ◽  
Vol 17 (11) ◽  
pp. 2809-2810
Author(s):  
Jody C. Culham
Keyword(s):  
Left Hand ◽  
Right Hand ◽  
The Right

Nog een suggestie voor het onderwerp van Rembrandts historiestuk te Leiden: De grootmoedigheid van Alexander

1987 ◽  
Vol 101 (2) ◽  
pp. 89-94
Author(s):  
J. Bruyn
Keyword(s):  
17Th Century ◽  
General Nature ◽  
History Painting ◽  
Emotional Words ◽  
Left Hand ◽  
Right Hand ◽  
Political Allegory ◽  
The Subject ◽  
Background Wave ◽  
The Right

AbstractOf the nine interpretations proposed for Rembraradt's history Painting of 1626 now at Leiden, none is really convincing. Il seems attractive to think of palamedes Condemned by Agamemncm as the subject because of its political significance in the year after the publication of Voredel's tragecty Palamedcs or Innocence Murdered, which denounced the execution of the Remonstrant leader Johan van Oldenbarnevelt in 1619. γet the scene depicted does not fit any episode frorn the Palamedes story. It appears rather to represent three young men appearing before a crowned figure who makes a pronouncement, probably one of magnanimity or clemency. It is conceivable that the subject was taken from Q. Curtius Rufus's Historiae Alexandri Magni Macedonis, ofwhich several editions, including translations into the vernacular, were published in Holland in the first decades of the 17th century. The episode in question was known to the young Rubens, but does not seem to have been illustrated by any other artist. At the beginning of the seventh book it is described how Alexander summoned before. him in the presence of the army two oj three brothers, who had been close friends of Philotas, a former, friend of his who had been executed for plotting against his life. The youngest brother, Poleinon, had panicked and fled but was caught and brought back at the very moment when Alexander had accused the brothers and the eldest, Amyntas, after having been released from his bonds and given a spear which he held in his left hand, had embarked on his szzccess ful defence. The appearance of Polemon infuriated the soldiers, but when he took the blame on himself and prrifessed his brothers' innocence, they were moved to tears. So too was Alexander who, prompted by their cries, absolved the brothers. This anecdote does at least explain some of the features of Rembrandt's scene. The young man standing on the right with his right hand raised as if swearing an oath would be the eloquent Amyntas with a spear in his left hand. Hidden behind him kneels the second brother, Simias, while Polemon, 'a young man just come to maturity and in the first bloom of his youth', has fallen on one knee in the foreground, underlining his emotional words with his right hand bressed to his heart. Alexander raises his sceptre in token of his absolution and some men in the background wave and shout from a socle they have climbed. Interpreted in this way, the scene coralains not a topical political allegory but, as would seem usual with history paintings, a message of a more general nature: the magnanimity of Alexander as an 'exemblum virtutis'.

scholarly journals Refinements of the Lower Bounds of the Jensen Functional

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Iva Franjić ◽  
Sadia Khalid ◽  
Josip Pečarić
Keyword(s):  
Lower Bounds ◽  
Jensen Inequality ◽  
Left Hand ◽  
Right Hand ◽  
Special Cases ◽  
Jensen Functional ◽  
The Difference ◽  
The Right

The lower bounds of the functional defined as the difference of the right-hand and the left-hand side of the Jensen inequality are studied. Refinements of some previously known results are given by applying results from the theory of majorization. Furthermore, some interesting special cases are considered.

Interosseous Muscle Pain in the Pianist's Hand: A Description of 27 Cases of Musician's Hand

2007 ◽  
Vol 22 (1) ◽  
pp. 24-25
Author(s):  
Naotaka Sakai
Keyword(s):  
Muscle Weakness ◽  
Muscle Pain ◽  
Deep Part ◽  
Piano Performance ◽  
Medical Problems ◽  
Main Symptom ◽  
Left Hand ◽  
Dorsal Hand ◽  
Right Hand ◽  
The Right

Among 703 professional pianists with medical problems in their hands seen by the author between 1981 and 2000, there were 27 patients who had interosseous muscle pain (23 women, 4 men; mean age, 30 yrs). The main symptom was dorsal hand pain during piano performance, especially when striking the keys with each finger rounded, mainly in the scale technique. Tenderness was noted in the deep part of the dorsal hand in the interosseous muscles, but not along or around the finger extensors. Patients sometimes complained of muscle weakness on abduction of the index, ring, and/or little fingers when performing octaves or chords on the piano keyboard. Resisted abduction and adduction testing of the fingers reproduced the pain which they experienced during or after performance. Pain occurred in the right hand in 10, left hand in 5, and bilaterally in 12. The pain was localized in the 4th and 5th interossei in 15 patients, in the 3rd and 4th in 14 patients; in the 2nd and 3rd in 11 patients; and in the 1st and 2nd in 1 patient.

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