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Author Noy, L.; Weiser, N.; Friedman, J.
Title (up) Synchrony in Joint Action Is Directed by Each Participant's Motor Control System Type Journal Article
Year 2017 Publication Frontiers in Psychology Abbreviated Journal Front. Psychol.
Volume 8 Issue Pages 531
Keywords visuomotor tracking; mirror game; intermittent control; joint action; motor control
Abstract In this work, we ask how the probability of achieving synchrony in joint action is affected by the choice of motion parameters of each individual. We use the mirror game paradigm to study how changes in leader�s motion parameters, specifically frequency and peak velocity, affect the probability of entering the state of co-confidence (CC) motion: a dyadic state of synchronized, smooth and co-predictive motions. In order to systematically study this question, we used a one-person version of the mirror game, where the participant mirrored piece-wise rhythmic movements produced by a computer on a graphics tablet. We systematically varied the frequency and peak velocity of the movements to determine how these parameters affect the likelihood of synchronized joint action. To assess synchrony in the mirror game we used the previously developed marker of co-confident (CC) motions: smooth, jitter-less and synchronized motions indicative of co-predicative control. We found that when mirroring movements with low frequencies (i.e., long duration movements), the participants never showed CC, and as the frequency of the stimuli increased, the probability of observing CC also increased. This finding is discussed in the framework of motor control studies showing an upper limit on the duration of smooth motion. We confirmed the relationship between motion parameters and the probability to perform CC with three sets of data of open-ended two-player mirror games. These findings demonstrate that when performing movements together, there are optimal movement frequencies to use in order to maximize the possibility of entering a state of synchronized joint action. It also shows that the ability to perform synchronized joint action is constrained by the properties of our motor control systems.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1664-1078 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 84
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Author Lerner, O.; Friedman, J.; Frenkel-Toledo, S.
Title (up) The effect of high-definition transcranial direct current stimulation intensity on motor performance in healthy adults: a randomized controlled trial Type Journal Article
Year 2021 Publication Journal of NeuroEngineering and Rehabilitation Abbreviated Journal J NeuroEngineering Rehabil
Volume 18 Issue Pages 103
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1743-0003 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 109
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Author Friedman, J.; Amiaz, A.; Korman, M.
Title (up) The online and offline effects of changing movement timing variability during training on a finger-opposition task Type Journal Article
Year 2022 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 12 Issue 1 Pages 13319
Keywords Fingers; Humans; *Learning; *Motor Skills; Movement; Psychomotor Performance; Upper Extremity
Abstract In motor learning tasks, there is mixed evidence for whether increased task-relevant variability in early learning stages leads to improved outcomes. One problem is that there may be a connection between skill level and motor variability, such that participants who initially have more variability may also perform worse on the task, so will have more room to improve. To avoid this confound, we experimentally manipulated the amount of movement timing variability (MTV) during training to test whether it improves performance. Based on previous studies showing that most of the improvement in finger-opposition tasks comes from optimizing the relative onset time of the finger movements, we used auditory cues (beeps) to guide the onset times of sequential movements during a training session, and then assessed motor performance after the intervention. Participants were assigned to three groups that either: (a) followed a prescribed random rhythm for their finger touches (Variable MTV), (b) followed a fixed rhythm (Fixed control MTV), or (c) produced the entire sequence following a single beep (Unsupervised control MTV). While the intervention was successful in increasing MTV during training for the Variable group, it did not lead to improved outcomes post-training compared to either control group, and the use of fixed timing led to significantly worse performance compared to the Unsupervised control group. These results suggest that manipulating MTV through auditory cues does not produce greater learning than unconstrained training in motor sequence tasks.
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Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-2322 ISBN Medium
Area Expedition Conference
Notes PMID:35922460; PMCID:PMC9349301 Approved no
Call Number Serial 115
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Author Zopf, R.; Friedman, J.; Williams, M.A.
Title (up) The plausibility of visual information for hand ownership modulates multisensory synchrony perception Type Journal Article
Year 2015 Publication Abbreviated Journal Experimental Brain Research
Volume 233 Issue 8 Pages 2311-2321
Keywords Multisensory perception; Temporal synchrony perception; Virtual hand; Body representations; Body ownership; Sensory predictions
Abstract We are frequently changing the position of our bodies and body parts within complex environments. How does the brain keep track of one’s own body? Current models of body ownership state that visual body ownership cues such as viewed object form and orientation are combined with multisensory information to correctly identify one’s own body, estimate its current location and evoke an experience of body ownership. Within this framework, it may be possible that the brain relies on a separate perceptual analysis of body ownership cues (e.g. form, orientation, multisensory synchrony). Alternatively, these cues may interact in earlier stages of perceptual processing—visually derived body form and orientation cues may, for example, directly modulate temporal synchrony perception. The aim of the present study was to distinguish between these two alternatives. We employed a virtual hand set-up and psychophysical methods. In a two-interval force-choice task, participants were asked to detect temporal delays between executed index finger movements and observed movements. We found that body-specifying cues interact in perceptual processing. Specifically, we show that plausible visual information (both form and orientation) for one’s own body led to significantly better detection performance for small multisensory asynchronies compared to implausible visual information. We suggest that this perceptual modulation when visual information plausible for one’s own body is present is a consequence of body-specific sensory predictions.
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Corporate Author Thesis
Publisher Springer Berlin Heidelberg Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0014-4819 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 78
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Author Prushansky, T.; Kaplan-Gadasi, L.; Friedman, J.
Title (up) The relationship between thoracic posture and ultrasound echo intensity of muscles spanning this region in healthy men and women Type Journal Article
Year 2022 Publication Physiotherapy Theory and Practice Abbreviated Journal Physiother Theory Pract
Volume Issue Pages 1-9
Keywords Ultrasound imaging; muscle echogenicity; posture; thoracic kyphosis
Abstract PURPOSE: Skeletal muscle echogenicity intensity (EI) is considered a measure of muscle quality, being associated with old age and pathologies. Whether EI variations can be identified in healthy adults, due to habitual shortened or elongated muscle position is unknown. Thus, this study aimed to assess the relationship between thoracic kyphosis angulation and EI scores of muscles spanning this region ((Lower Trapezius (LT), Rhomboid Major (RM), Erector Spine (ES)) in healthy young people and in addition to examine the relationship between the change in thoracic kyphosis angle from relaxed to upright position (� degrees ) and the EI of these muscles. METHODS: Thoracic kyphosis in relaxed and erect standing was measured using a digital inclinometer in 29 healthy adults (16 women, 13 men), aged 25-35 years. The thoracic kyphosis angles including the difference between relaxed and erect postures (� degrees ) were correlated to the EI scores of right and left LT, RM and ES. RESULTS: No significant differences in EI were found between the 3 muscles EI or between sides, hence they were pooled together to a total thoracic EI score (TTEI). Although the TTEI did not correlate with relaxed or erect thoracic kyphosis, it was significantly but negatively correlated with � degrees in the entire group: Pearson's correlation coefficient of r = -0.544; p = .01 and in men; r = -0.732; p = .01, failing to reach significance in women; r = -0.457. CONCLUSION: The negative association between the EI of the explored muscles and � degrees could imply a possible relationship between these muscles range of movement excursions and their composition.
Address Department of Physical Therapy, the Stanley Stayer School of Health Professions, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-3985 ISBN Medium
Area Expedition Conference
Notes PMID:35125048 Approved no
Call Number Serial 116
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