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Author Noy, L.; Alon, U.; Friedman, J.
Title Corrective jitter motion shows similar individual frequencies for the arm and the finger Type Journal Article
Year 2015 Publication Experimental Brain Research Abbreviated Journal Exp Brain Res
Volume 233 Issue 4 Pages 1307-1320
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Abstract A characteristic of visuomotor tracking of non-regular oscillating stimuli are high-frequency jittery corrective motions, oscillating around the tracked stimuli. However, the properties of these corrective jitter responses are not well understood. For example, does the jitter response show an idiosyncratic signature? What is the relationship between stimuli properties and jitter properties? Is the jitter response similar across effectors with different inertial properties? To answer these questions, we measured participants' jitter frequencies in two tracking tasks in the arm and the finger. Thirty participants tracked the same set of eleven non-regular oscillating stimuli, vertically moving on a screen, once with forward-backward arm movements (holding a tablet stylus) and once with upward-downward index finger movements (with a motion tracker attached). Participants' jitter frequencies and tracking errors varied systematically as a function of stimuli frequency and amplitude. Additionally, there were clear individual differences in average jitter frequencies between participants, ranging from 0.7 to 1.15 Hz, similar to values reported previously. A comparison of individual jitter frequencies in the two tasks showed a strong correlation between participants' jitter frequencies in the finger and the arm, despite the very different inertial properties of the two effectors. This result suggests that the corrective jitter response stems from common neural processes.
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0014-4819 ISBN Medium
Area Expedition Conference
Notes PMID:25630905 Approved no
Call Number Serial 76
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Author Awasthi, B.; Williams, M.A.; Friedman, J.
Title Examining the role of red background in magnocellular contribution to face perception Type Journal Article
Year 2016 Publication PeerJ Abbreviated Journal PeerJ
Volume 4 Issue Pages e1617
Keywords (up)
Abstract This study examines the role of the magnocellular system in the early stages of face perception, in particular sex categorization. Utilizing the specific property of magnocellular suppression in red light, we investigated visually guided reaching to low and high spatial frequency hybrid faces against red and grey backgrounds. The arm movement curvature measure shows that reduced response of the magnocellular pathway interferes with the low spatial frequency component of face perception. This finding provides behavioral evidence for magnocellular contribution to non-emotional aspect of face perception.
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Publisher Place of Publication Editor
Language en Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 2167-8359 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 81
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Author Frenkel-Toledo, S.; Liebermann, D.G.; Bentin, S.; Soroker, N.
Title Dysfunction of the Human Mirror Neuron System in Ideomotor Apraxia: Evidence from Mu Suppression Type Journal Article
Year 2016 Publication Journal of Cognitive Neuroscience Abbreviated Journal J Cogn Neurosci
Volume Issue Pages
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Abstract Stroke patients with ideomotor apraxia (IMA) have difficulties controlling voluntary motor actions, as clearly seen when asked to imitate simple gestures performed by the examiner. Despite extensive research, the neurophysiological mechanisms underlying failure to imitate gestures in IMA remain controversial. The aim of the current study was to explore the relationship between imitation failure in IMA and mirror neuron system (MNS) functioning. Mirror neurons were found to play a crucial role in movement imitation and in imitation-based motor learning. Their recruitment during movement observation and execution is signaled in EEG recording by suppression of the lower (8-10 Hz) mu range. We examined the modulation of EEG in this range in stroke patients with left (n = 21) and right (n = 15) hemisphere damage during observation of video clips showing different manual movements. IMA severity was assessed by the DeRenzi's standardized diagnostic test. Results showed that failure to imitate observed manual movements correlated with diminished mu suppression in patients with damage to the right inferior parietal lobule and in patients with damage to the right inferior frontal gyrus pars opercularis-areas where major components of the human MNS are assumed to reside. Voxel-based lesion symptom mapping revealed a significant impact on imitation capacity for the left inferior and superior parietal lobules and the left post central gyrus. Both left and right hemisphere damages were associated with imitation failure typical of IMA, yet a clear demonstration of relationship to the MNS was obtained only in the right hemisphere damage group. Suppression of the 8-10 Hz range was stronger in central compared with occipital sites, pointing to a dominant implication of mu rather than alpha rhythms. However, the suppression correlated with De Renzi's apraxia test scores not only in central but also in occipital sites, suggesting a multifactorial mechanism for IMA, with a possible impact for deranged visual attention (alpha suppression) beyond the effect of MNS damage (mu suppression).
Address Loewenstein Hospital, Ra'anana, 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 0898-929X ISBN Medium
Area Expedition Conference
Notes PMID:26942323 Approved no
Call Number Serial 82
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Author Raveh, E.; Friedman, J.; Portnoy, S.
Title Visuomotor behaviors and performance in a dual-task paradigm with and without vibrotactile feedback when using a myoelectric controlled hand Type Journal Article
Year 2018 Publication Assistive Technology Abbreviated Journal Assistive Technology
Volume 30 Issue Pages 274-280
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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 1040-0435 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 85
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Author Shaklai, S.; Mimouni-Bloch, A.; Levin, M.; Friedman, J.
Title Development of finger force coordination in children Type Journal Article
Year 2017 Publication Experimental Brain Research Abbreviated Journal
Volume 235 Issue 12 Pages 3709–3720
Keywords (up)
Abstract Coordination is often observed as body parts moving together. However, when producing force with multiple fingers, the optimal coordination is not to produce similar forces with each finger, but rather for each finger to correct mistakes of other fingers. In this study, we aim to determine whether and how this skill develops in children aged 4-12 years. We measured this sort of coordination using the uncontrolled manifold hypothesis (UCM). We recorded finger forces produced by 60 typically developing children aged between 4 and 12 years in a finger-pressing task. The children controlled the height of an object on a screen by the total amount of force they produced on force sensors. We found that the synergy index, a measure of the relationship between “good” and “bad” variance, increased linearly as a function of age. This improvement was achieved by a selective reduction in “bad” variance rather than an increase in “good” variance. We did not observe differences between males and females, and the synergy index was not able to predict outcomes of upper limb behavioral tests after controlling for age. As children develop between the ages of 4 and 12 years, their ability to produce negative covariation between their finger forces improves, likely related to their improved ability to perform dexterous tasks.
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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 1432-1106 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Shaklai2017 Serial 86
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