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	Author	Dempsey-Jones, H.; Wesselink, D.B.; Friedman, J.; Makin, T.R.
	Title	Organized Toe Maps in Extreme Foot Users			Type	Journal Article
	Year	2019	Publication	Cell Reports	Abbreviated Journal	Cell Reports
	Volume	28	Issue	11	Pages	2748-2756.e4
	Keywords
	Abstract	Although the fine-grained features of topographic maps in the somatosensory cortex can be shaped by everyday experience, it is unknown whether behavior can support the expression of somatotopic maps where they do not typically occur. Unlike the fingers, represented in all primates, individuated toe maps have only been found in non-human primates. Using 1-mm resolution fMRI, we identify organized toe maps in two individuals born without either upper limb who use their feet to substitute missing hand function and even support their profession as foot artists. We demonstrate that the ordering and structure of the artists’ toe representation mimics typical hand representation. We further reveal “hand-like” features of activity patterns, not only in the foot area but also similarly in the missing hand area. We suggest humans may have an innate capacity for forming additional topographic maps that can be expressed with appropriate experience.
	Address
	Corporate Author				Thesis
	Publisher	Elsevier	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	2211-1247	ISBN		Medium
	Area		Expedition		Conference
	Notes	doi: 10.1016/j.celrep.2019.08.027			Approved	no
	Call Number				Serial	99
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	Author	Biess, A.; Liebermann, D.G.; Flash, T.
	Title	A computational model for redundant human three-dimensional pointing movements: integration of independent spatial and temporal motor plans simplifies movement dynamics			Type	Journal Article
	Year	2007	Publication	The Journal of Neuroscience : the Official Journal of the Society for Neuroscience	Abbreviated Journal	J Neurosci
	Volume	27	Issue	48	Pages	13045-13064
	Keywords	Analysis of Variance; Arm/physiology; Biomechanics; Computer Simulation; Humans; Models, Biological; Movement/physiology; Nonlinear Dynamics; Posture/physiology; Psychomotor Performance/physiology; Range of Motion, Articular/physiology; Reaction Time/physiology; Space Perception/physiology; Time Factors; Torque
	Abstract	Few computational models have addressed the spatiotemporal features of unconstrained three-dimensional (3D) arm motion. Empirical observations made on hand paths, speed profiles, and arm postures during point-to-point movements led to the assumption that hand path and arm posture are independent of movement speed, suggesting that the geometric and temporal properties of movements are decoupled. In this study, we present a computational model of 3D movements for an arm with four degrees of freedom based on the assumption that optimization principles are separately applied at the geometric and temporal levels of control. Geometric properties (path and posture) are defined in terms of geodesic paths with respect to the kinetic energy metric in the Riemannian configuration space. Accordingly, a geodesic path can be generated with less muscular effort than on any other, nongeodesic path, because the sum of all configuration-speed-dependent torques vanishes. The temporal properties of the movement (speed) are determined in task space by minimizing the squared jerk along the selected end-effector path. The integration of both planning levels into a single spatiotemporal representation simplifies the control of arm dynamics along geodesic paths and results in movements with near minimal torque change and minimal peak value of kinetic energy. Thus, the application of Riemannian geometry allows for a reconciliation of computational models previously proposed for the description of arm movements. We suggest that geodesics are an emergent property of the motor system through the exploration of dynamical space. Our data validated the predictions for joint trajectories, hand paths, final postures, speed profiles, and driving torques.
	Address	Department of Mathematics, Weizmann Institute of Science, 76100 Rehovot, Israel. armin.biess@weizmann.ac.il
	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	0270-6474	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:18045899			Approved	no
	Call Number				Serial	35
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	Author	Tenenbaum, G.; Kohler, N.; Shraga, S.; Liebermann, D.G.; Lidor, R.
	Title	Anticipation and confidence of decisions related to skilled performance			Type	Journal Article
	Year	1996	Publication	Journal of Sport Psychology	Abbreviated Journal
	Volume	27	Issue		Pages	293-307
	Keywords
	Abstract	This study was carried out to examine anticipatory decisions of novice, intermediate, and expert tennis players and the confidence with which these decisions are made by these athletes. Perceived eye-focus was also measured to verify whether it is related to expertise level prior to action execution. Forty-five Australian players, 15 in each skill category, were exposed to 6 temporal occluded film conditions (480, 320, 160 ms prior to racquet-ball contact, at contact, and 160 and 320 ms after contact) in randomized order within 8 tennis strokes. In each condition, after viewing the filmed sequence, they were asked to report the final ball location of the opponent's stroke, how confident they were in this decision, and their perceived eye-focus location during the sequence. Experts and intermediates were superior in anticipatory decisions to their counterparts, only under short exposure durations. Novices showed more confidence than experts and intermediates at the beginning of the sequence, but after 160 and 320 ms of ball-racquet contact, experts were much more confident than novices, and intermediates. Self-reported eye-focus differed substantially with respect to expertise level. While experts attended to several locations prior to ball-racquet contact, intermediate and novice players gazed at one location. After contact, the reverse was evident. The findings are in partial agreement with other studies which have applied the temporal occlusion paradigm to study expert-novice differences in anticipatory skills.
	Address
	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		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	59
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	Author	Melzer, I.; Krasovsky, T.; Oddsson, L.I.E.; Liebermann, D.G.
	Title	Age-related differences in lower-limb force-time relation during the push-off in rapid voluntary stepping			Type	Journal Article
	Year	2010	Publication	Clinical Biomechanics (Bristol, Avon)	Abbreviated Journal	Clin Biomech (Bristol, Avon)
	Volume	25	Issue	10	Pages	989-994
	Keywords	Accidental Falls/prevention & control; Age Factors; Aged; Aged, 80 and over; Aging/physiology; Biomechanics; Female; Gait/physiology; Humans; Male; Postural Balance; Walking/physiology
	Abstract	BACKGROUND: This study investigated the force-time relationship during the push-off stage of a rapid voluntary step in young and older healthy adults, to study the assumption that when balance is lost a quick step may preserve stability. The ability to achieve peak propulsive force within a short time is critical for the performance of such a quick powerful step. We hypothesized that older adults would achieve peak force and power in significantly longer times compared to young people, particularly during the push-off preparatory phase. METHODS: Fifteen young and 15 older volunteers performed rapid forward steps while standing on a force platform. Absolute anteroposterior and body weight normalized vertical forces during the push-off in the preparation and swing phases were used to determine time to peak and peak force, and step power. Two-way analyses of variance ('Group' [young-older] by 'Phase' [preparation-swing]) were used to assess our hypothesis (P </= 0.05). FINDINGS: Older people exerted lower peak forces (anteroposterior and vertical) than young adults, but not necessarily lower peak power. More significantly, they showed a longer time to peak force, particularly in the vertical direction during the preparation phase. INTERPRETATIONS: Older adults generate propulsive forces slowly and reach lower magnitudes, mainly during step preparation. The time to achieve a peak force and power, rather than its actual magnitude, may account for failures in quickly performing a preventive action. Such delay may be associated with the inability to react and recruit muscles quickly. Thus, training elderly to step fast in response to relevant cues may be beneficial in the prevention of falls.
	Address	Department of Physical Therapy, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 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	0268-0033	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:20724044			Approved	no
	Call Number				Serial	51
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	Author	Portnoy, S.; Rosenberg, L.; Alazraki, T.; Elyakim, E.; Friedman, J.
	Title	Differences in Muscle Activity Patterns and Graphical Product Quality in Children Copying and Tracing Activities on Horizontal or Vertical Surfaces			Type	Journal Article
	Year	2015	Publication	Journal of Electromyography and Kinesiology	Abbreviated Journal	Journal of Electromyography and Kinesiology
	Volume	25	Issue	3	Pages	540�547
	Keywords	Motor equivalence; Electromyography; Tablet; Occupational Therapy; Muscle fatigue; Motor control
	Abstract	The observation that a given task, e.g. producing a signature, looks similar when created by different motor commands and different muscles groups is known as motor equivalence. Relatively little data exists regarding the characteristics of motor equivalence in children. In this study, we compared the level of performance when performing a tracing task and copying figures in two common postures: while sitting at a desk and while standing in front of a wall, among preschool children. In addition, we compared muscle activity patterns in both postures. Specifically, we compared the movements of 35 five- to six-year old children, recording the same movements of copying figures and path tracing on an electronic tablet in both a horizontal orientation, while sitting, and a vertical orientation, while standing. Different muscle activation patterns were observed between the postures, however no significant difference in the performance level was found, providing evidence of motor equivalence at this young age. The study presents a straightforward method of assessing motor equivalence that can be extended to other stages of development as well as motor disorders.
	Address
	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	1050-6411	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	77
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