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Uncontrolled manifold

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https://www.readbyqxmd.com/read/29873618/stability-of-hand-force-production-ii-ascending-and-descending-synergies
#1
Sasha Reschechtko, Mark L Latash
We combined the theory of neural control of movement with referent coordinates and the uncontrolled manifold hypothesis to investigate multi-finger coordination. We tested hypotheses related to stabilization of performance by co-varying control variables, translated into apparent stiffness and referent coordinate, at different levels of an assumed hierarchy of control. Subjects produced an accurate combination of total force and total moment of force with the four fingers under visual feedback on both variables and after feedback was partly or completely removed...
June 6, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29573980/systemic-effects-of-deep-brain-stimulation-on-synergic-control-in-parkinson-s-disease
#2
Ali Falaki, Hang Jin Jo, Mechelle M Lewis, Barbara O'Connell, Sol De Jesus, James McInerney, Xuemei Huang, Mark L Latash
OBJECTIVE: We explored effects of deep brain stimulation (DBS) in patients with Parkinson's disease (PD) on the synergic control of fingers in a multi-finger force production task and of muscles in a task involving vertical posture. METHODS: The finger task involved the four fingers of a hand producing accurate total force followed by a targeted quick force pulse. The postural task involved releasing a load from extended arms. The analysis of synergies was performed within the framework of the uncontrolled manifold hypothesis...
June 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29564506/stability-of-steady-hand-force-production-explored-across-spaces-and-methods-of-analysis
#3
Paulo B de Freitas, Sandra M S F Freitas, Mechelle M Lewis, Xuemei Huang, Mark L Latash
We used the framework of the uncontrolled manifold (UCM) hypothesis and explored the reliability of several outcome variables across different spaces of analysis during a very simple four-finger accurate force production task. Fourteen healthy, young adults performed the accurate force production task with each hand on 3 days. Small spatial finger perturbations were generated by the "inverse piano" device three times per trial (lifting the fingers 1 cm/0.5 s and lowering them). The data were analyzed using the following main methods: (1) computation of indices of the structure of inter-trial variance and motor equivalence in the space of finger forces and finger modes, and (2) analysis of referent coordinates and apparent stiffness values for the hand...
March 22, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/29532100/multi-finger-synergies-and-the-muscular-apparatus-of-the-hand
#4
Cristian Cuadra, Angelo Bartsch, Paula Tiemann, Sasha Reschechtko, Mark L Latash
We explored whether the synergic control of the hand during multi-finger force production tasks depends on the hand muscles involved. Healthy subjects performed accurate force production tasks and targeted force pulses while pressing against loops positioned at the level of fingertips, middle phalanges, and proximal phalanges. This varied the involvement of the extrinsic and intrinsic finger flexors. The framework of the uncontrolled manifold (UCM) hypothesis was used to analyze the structure of inter-trial variance, motor equivalence, and anticipatory synergy adjustments prior to the force pulse in the spaces of finger forces and finger modes (hypothetical finger-specific control signals)...
May 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/29492588/anticipatory-coarticulation-in-non-speeded-arm-movements-can-be-motor-equivalent-carry-over-coarticulation-always-is
#5
Eva Hansen, Britta Grimme, Hendrik Reimann, Gregor Schöner
In a sequence of arm movements, any given segment could be influenced by its predecessors (carry-over coarticulation) and by its successor (anticipatory coarticulation). To study the interdependence of movement segments, we asked participants to move an object from an initial position to a first and then on to a second target location. The task involved ten joint angles controlling the three-dimensional spatial path of the object and hand. We applied the principle of the uncontrolled manifold (UCM) to analyze the difference between joint trajectories that either affect (non-motor equivalent) or do not affect (motor equivalent) the hand's trajectory in space...
May 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/29474421/development-of-reaching-during-mid-childhood-from-a-developmental-systems-perspective
#6
Laura Golenia, Marina M Schoemaker, Egbert Otten, Leonora J Mouton, Raoul M Bongers
Inspired by the Developmental Systems perspective, we studied the development of reaching during mid-childhood (5-10 years of age) not just at the performance level (i.e., endpoint movements), as commonly done in earlier studies, but also at the joint angle level. Because the endpoint position (i.e., the tip of the index finger) at the reaching target can be achieved with multiple joint angle combinations, we partitioned variability in joint angles over trials into variability that does not (goal-equivalent variability, GEV) and that does (non-goal-equivalent variability, NGEV) influence the endpoint position, using the Uncontrolled Manifold method...
2018: PloS One
https://www.readbyqxmd.com/read/29277305/stability-of-kinesthetic-perception-in-efferent-afferent-spaces-the-concept-of-iso-perceptual-manifold
#7
Mark L Latash
The main goal of this paper is to introduce the concept of iso-perceptual manifold for perception of body configuration and related variables (kinesthetic perception) and to discuss its relation to the equilibrium-point hypothesis and the concepts of reference coordinate and uncontrolled manifold. Hierarchical control of action is postulated with abundant transformations between sets of spatial reference coordinates for salient effectors at different levels. Iso-perceptual manifold is defined in the combined space of afferent and efferent variables as the subspace corresponding to a stable percept...
February 21, 2018: Neuroscience
https://www.readbyqxmd.com/read/29200629/trunk-lean-gait-decreases-multi-segmental-coordination-in-the-vertical-direction
#8
Kazuki Tokuda, Masaya Anan, Tomonori Sawada, Kenji Tanimoto, Takuya Takeda, Yuta Ogata, Makoto Takahashi, Nobuhiro Kito, Koichi Shinkoda
[Purpose] The strategy of trunk lean gait to reduce external knee adduction moment (KAM) may affect multi-segmental synergy control of center of mass (COM) displacement. Uncontrolled manifold (UCM) analysis is an evaluation index to understand motor variability. The purpose of this study was to investigate how motor variability is affected by using UCM analysis on adjustment of the trunk lean angle. [Subjects and Methods] Fifteen healthy young adults walked at their preferred speed under two conditions: normal and trunk lean gait...
November 2017: Journal of Physical Therapy Science
https://www.readbyqxmd.com/read/29162977/perioperative-management-of-patients-with-diabetes
#9
REVIEW
Vivien Leung, Kristal Ragbir-Toolsie
Hyperglycemia has long been recognized to have detrimental effects on postoperative outcomes in patients undergoing surgery. The manifestations of uncontrolled diabetes are manifold and can include risk of hyperglycemic crises, postoperative infection, poor wound healing, and increased mortality. There is substantial literature supporting the role of diligent glucose control in the prevention of adverse surgical outcomes, but considerable debate remains as to the optimal glucose targets. Hence, most organizations advocate the avoidance of hypoglycemia while striving for adequate glucose control in the perioperative period...
2017: Health Services Insights
https://www.readbyqxmd.com/read/29150344/biomechanical-mechanism-of-lateral-trunk-lean-gait-for-knee-osteoarthritis-patients
#10
Kazuki Tokuda, Masaya Anan, Makoto Takahashi, Tomonori Sawada, Kenji Tanimoto, Nobuhiro Kito, Koichi Shinkoda
The biomechanical mechanism of lateral trunk lean gait employed to reduce external knee adduction moment (KAM) for knee osteoarthritis (OA) patients is not well known. This mechanism may relate to the center of mass (COM) motion. Moreover, lateral trunk lean gait may affect motor control of the COM displacement. Uncontrolled manifold (UCM) analysis is an evaluation index used to understand motor control and variability of the motor task. Here we aimed to clarify the biomechanical mechanism to reduce KAM during lateral trunk lean gait and how motor variability controls the COM displacement...
January 3, 2018: Journal of Biomechanics
https://www.readbyqxmd.com/read/29112886/uncontrolled-manifold-analysis-of-joint-angle-variability-during-table-tennis-forehand
#11
Yoichi Iino, Shinsuke Yoshioka, Senshi Fukashiro
This study was conducted with the objective of evaluating the variance structure of the trunk and racket arm joint angles in table tennis topspin forehand using the uncontrolled manifold (UCM) approach, regarding racket orientation as the task variable. Nine advanced and eight intermediate male collegiate table tennis players performed the topspin strokes against backspin balls. The trunk, upper limb, and racket were modeled as six rigid-link segments with a total of 16 rotation degrees of freedom. The UCM analysis was conducted using 30 trial datasets per participant to quantify the degree of redundancy exploitation needed to stabilize the vertical and horizontal angles of the racket...
December 2017: Human Movement Science
https://www.readbyqxmd.com/read/29103987/special-radiobiological-features-of-second-cancer-risk-after-particle-radiotherapy
#12
Klaus-Rüdiger Trott
In absolute terms: second cancer risks from radiotherapy of first cancers in adults are small compared to the benefits from radiotherapy but this is not so for radiotherapy of childhood cancers. Moreover, the radiation dose dependence of cancer induction differs between organs and tissues. The organ-specific dose dependence of second cancer risks may indicate the existence of different radiobiological mechanisms. As an inevitable consequence of the age dependence of organ sensitivity to second cancer induction, the organ/tissue weighting factors which have been proposed by ICRP for calculating effective dose (the dose unit Sv) and for risk estimation in the general population should not be used in medical radiation exposures...
October 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/29081743/the-propagation-of-movement-variability-in-time-a-methodological-approach-for-discrete-movements-with-multiple-degrees-of-freedom
#13
Melanie Krüger, Andreas Straube, Thomas Eggert
In recent years, theory-building in motor neuroscience and our understanding of the synergistic control of the redundant human motor system has significantly profited from the emergence of a range of different mathematical approaches to analyze the structure of movement variability. Approaches such as the Uncontrolled Manifold method or the Noise-Tolerance-Covariance decomposition method allow to detect and interpret changes in movement coordination due to e.g., learning, external task constraints or disease, by analyzing the structure of within-subject, inter-trial movement variability...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/29061556/impact-of-an-electronic-monitoring-intervention-to-improve-adherence-to-inhaled-medication-in-patients-with-asthma-and-chronic-obstructive-pulmonary-disease-study-protocol-for-a-randomized-controlled-trial
#14
Claudia Gregoriano, Thomas Dieterle, Selina Dürr, Isabelle Arnet, Kurt E Hersberger, Jörg D Leuppi
BACKGROUND: Despite progress in pharmacological and non-pharmacological treatment in recent years, the burden of disease among patients with asthma and chronic obstructive pulmonary disease (COPD) is high and patients are frequently hospitalized due to exacerbations. Reasons for uncontrolled diseases are manifold, but are often associated with poor inhalation technique and non-adherence to the prescribed treatment plan. This causes substantial mortality, morbidity, and costs to the healthcare system...
October 23, 2017: JMIR Research Protocols
https://www.readbyqxmd.com/read/29057143/phytotherapy-of-high-blood-pressure-in-three-phytogeographic-regions-of-cameroon
#15
Nole Tsabang, Clement G Yedjou, Paul B Tchounwou
OBJECTIVE: High blood pressure is a public health challenge worldwide. According to World Health Organization, 30% of men and 50% of women 65 to 75 years old are suffering from high blood pressure. The number of hypertensive patients in the world will attain 1.56 billion of people, with 60% increase in prevalence. The incidence of high blood pressure increases with age, but nowadays, is being noticed an increasing incidence in young people. The socio-cultural medicine may provide new solutions in the management of this pathology...
2017: Pharmaceutica Analytica Acta
https://www.readbyqxmd.com/read/28939197/uncontrolled-manifold-hypothesis-organization-of-leg-joint-variance-in-humans-while-walking-in-a-wide-range-of-speeds
#16
Vito Monaco, Peppino Tropea, Lucio A Rinaldi, Silvestro Micera
This study aimed at investigating the organization of joint angle variability during walking by using the uncontrolled manifold (UCM) theory. We tested two hypotheses: i. the coordinative mechanism underlying joint angle variance during the stance phase is compatible with a kinematic synergy that stabilizes the centre of mass (CoM) position; ii. the walking speed affects the variance components onto and orthogonal to the UCM. Eight healthy subjects (26.0±2.0years old) steadily walked on a treadmill at five normalised speeds (from 0...
February 2018: Human Movement Science
https://www.readbyqxmd.com/read/28936720/development-of-finger-force-coordination-in-children
#17
Sharon Shaklai, Aviva Mimouni-Bloch, Moran Levin, Jason Friedman
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...
December 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28931612/cue-induced-changes-in-the-stability-of-finger-force-production-tasks-revealed-by-the-uncontrolled-manifold-analysis
#18
Mitchell Tillman, Satyajit Ambike
A motor system configured to maximize the stability of its current state cannot dexterously transition between states. Yet, we routinely resolve the stability-dexterity conflict and rapidly change our current behavior without allowing it to become unstable before the desired transition. The phenomenon called anticipatory synergy adjustment (ASA) partly describes how the central nervous system handles this conflict. ASA is a continuous decrease in the stability of the current motor state beginning 150-400 ms before a rapid state transition accomplished using redundant sets of motor inputs (more input variables than task-specific output variables)...
January 1, 2018: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28924748/a-multi-joint-model-of-quiet-upright-stance-accounts-for-the-uncontrolled-manifold-structure-of-joint-variance
#19
Hendrik Reimann, Gregor Schöner
The upright body in quiet stance is usually modeled as a single-link inverted pendulum. This agrees with most of the relevant sensory organs being at the far end of the pendulum, i.e., the eyes and the vestibular system in the head. Movement of the body in quiet stance has often been explained in terms of the "ankle strategy," where most movement is generated by the ankle musculature, while more proximal muscle groups are only rarely activated for faster movements or in response to perturbations, for instance, by flexing at the hips in what has been called the "hip strategy...
December 2017: Biological Cybernetics
https://www.readbyqxmd.com/read/28915097/synergies-and-motor-equivalence-in-voluntary-sway-tasks-the-effects-of-visual-and-mechanical-constraints
#20
Mariusz P Furmanek, Stanisław Solnik, Daniele Piscitelli, Omid Rasouli, Ali Falaki, Mark L Latash
The authors used two analyses developed within the framework of the uncontrolled manifold hypothesis to quantify multimuscle synergies during voluntary body sway: analysis of intertrial variance and analysis of motor equivalence with respect to the center of pressure (COP) trajectory. Participants performed voluntary sway tasks in the anteroposterior direction at 0.33 and 0.66 Hz. Muscle groups were identified in the space of muscle activations and used as elemental variables in the synergy analyses. Changing mechanical and vision feedback-based constraints led to significant changes in indices of sway performance such as COP deviations in the uninstructed, mediolateral direction and indices of spontaneous postural sway...
September 15, 2017: Journal of Motor Behavior
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