scholarly journals Trial-to-trial dynamics and learning in a generalized, redundant reaching task

2013 ◽  
Vol 109 (1) ◽  
pp. 225-237 ◽  
Author(s):  
Jonathan B. Dingwell ◽  
Rachel F. Smallwood ◽  
Joseph P. Cusumano
Keyword(s):  
Goal Function ◽  
General Strategy ◽  
Reaching Task ◽  
Subsequent Learning ◽  
Learning Rates ◽  
Specific Goal ◽  
Goal Equivalent Manifold ◽  
Variance Ratios ◽  
Goal Functions ◽  
Do So

If humans exploit task redundancies as a general strategy, they should do so even if the redundancy is decoupled from the physical implementation of the task itself. Here, we derived a family of goal functions that explicitly defined infinite possible redundancies between distance ( D) and time ( T) for unidirectional reaching. All [ T, D] combinations satisfying any specific goal function defined a goal-equivalent manifold (GEM). We tested how humans learned two such functions, D/T = c (constant speed) and D·T = c, that were very different but could both be achieved by neurophysiologically and biomechanically similar reaching movements. Subjects were never explicitly shown either relationship, but only instructed to minimize their errors. Subjects exhibited significant learning and consolidation of learning for both tasks. Initial error magnitudes were higher, but learning rates were faster, for the D· T task than for the D/ T task. Learning the D/ T task first facilitated subsequent learning of the D· T task. Conversely, learning the D· T task first interfered with subsequent learning of the D/ T task. Analyses of trial-to-trial dynamics demonstrated that subjects actively corrected deviations perpendicular to each GEM faster than deviations along each GEM to the same degree for both tasks, despite exhibiting significantly greater variance ratios for the D/ T task. Variance measures alone failed to capture critical features of trial-to-trial control. Humans actively exploited these abstract task redundancies, even though they did not have to. They did not use readily available alternative strategies that could have achieved the same performance.

Inter-Trial Dynamics of Repeated Skilled Movements

2007 ◽  
Author(s):  
Joby John ◽  
Joseph P. Cusumano
Keyword(s):  
Hierarchical Control ◽  
Goal Function ◽  
Human Movements ◽  
Control Scheme ◽  
Goal Level ◽  
Goal Equivalent Manifold ◽  
Goal Functions ◽  
The Stability ◽  
Passive Sensitivity ◽  
Definition Of

In this paper, we develop a class of discrete dynamical systems for modeling repeated, goal-directed, kinematically redundant human movements. The approach is based on a mathematical definition of movement tasks in terms of goal functions. Each goal function can give rise to an associated goal equivalent manifold (GEM), which contains all body states that exactly satisfy the task requirements. A hierarchical control scheme involving in-trial action templates and inter-trial stochastic optimal error correction is included to generate a nonlinear map for the repeated execution of the task. A simple throwing task is used to illustrate the underlying concepts and to develop a model problem for further study. The performance at the goal level, as measured by the root mean square error, is shown to result from factors that are measures of passive sensitivity, the magnitude of body fluctuations, the orientation of fluctuations with the GEM, and the stability properties of the inter-trial controller. The action of the inter-trial controller developed for our model system is simulated and is shown to agree with the mathematically predicted performance.

The Nature Of Strategic-Decision-Making Models

2011 ◽  
pp. 241-271
Author(s):  
Tamio Shimizu ◽  
Marley Monteiro de Carvalho ◽  
Fernando Jose Barbin
Keyword(s):  
Decision Making ◽  
Goal Function ◽  
Optimization Method ◽  
Strategic Decision ◽  
Optimal Decision ◽  
Problem Solution ◽  
Goal Functions ◽  
Optimal Decision Making ◽  
The Individual ◽  
Optimum Solution

In the multiple goal function problems, there is no optimum solution fully satisfying all goals at the same time. The individual goal’s functions are, in general, conflicting and it is not possible to have an optimization method to solve the problem. There is usually a consensus solution satisfying minimal criteria of optimum values for each individual goal function. This consensus is based on the Pareto’s principle presented in chapter nine. The optimal decision making in problems with multiple goals will be analyzed at the end of this chapter (Goicoechea et al., 1982; Keeney & Raiffa, 1976; Dyson, 1990; Saaty, 1980, 1994; Bonabeau, 2003; Charan, 2001; Choo, 1998; Day et al., 1997). In considering restrictions across several scenarios, the problem solution becomes more difficult due to the high number of possible combinations of goal functions and scenarios to be considered.

scholarly journals The effects of motor modularity on performance, learning and generalizability in upper-extremity reaching: a computational analysis

2020 ◽  
Vol 17 (167) ◽  
pp. 20200011
Author(s):  
Mazen Al Borno ◽  
Jennifer L. Hicks ◽  
Scott L. Delp
Keyword(s):  
Upper Extremity ◽  
Realistic Model ◽  
Computational Time ◽  
Muscle Synergies ◽  
Performance Deficits ◽  
Reaching Task ◽  
Learning Rates ◽  
The Central Nervous System ◽  
The Rich ◽  
Low Dimensional

It has been hypothesized that the central nervous system simplifies the production of movement by limiting motor commands to a small set of modules known as muscle synergies. Recently, investigators have questioned whether a low-dimensional controller can produce the rich and flexible behaviours seen in everyday movements. To study this issue, we implemented muscle synergies in a biomechanically realistic model of the human upper extremity and performed computational experiments to determine whether synergies introduced task performance deficits, facilitated the learning of movements, and generalized to different movements. We derived sets of synergies from the muscle excitations our dynamic optimizations computed for a nominal task (reaching in a plane). Then we compared the performance and learning rates of a controller that activated all muscles independently to controllers that activated the synergies derived from the nominal reaching task. We found that a controller based on synergies had errors within 1 cm of a full-dimensional controller and achieved faster learning rates (as estimated from computational time to converge). The synergy-based controllers could also accomplish new tasks—such as reaching to targets on a higher or lower plane, and starting from alternative initial poses—with average errors similar to a full-dimensional controller.

scholarly journals Deficits in Skilled Motor and Auditory Learning in a Rat Model of Rett Syndrome

2020 ◽  
Author(s):  
Katherine S. Adcock ◽  
Abigail E. Blount ◽  
Robert A. Morrison ◽  
Amanda Alvarez-Dieppa ◽  
Michael P. Kilgard ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Discrimination Task ◽  
Neurodevelopmental Disorder ◽  
Motor Task ◽  
Speech Discrimination ◽  
Auditory Learning ◽  
Reaching Task ◽  
Developmental Regression ◽  
Learning Rates ◽  
And Performance

Abstract Background: Rett Syndrome is an X-linked neurodevelopmental disorder caused by a mutation in the gene MECP2. Individuals with Rett Syndrome display developmental regression at an early age, and develop a range of motor, auditory, cognitive and social impairments. Several studies have successfully modeled some aspects of dysfunction and Rett Syndrome-like phenotypes in transgenic mouse and rat models bearing mutations in the MECP2 gene. Here, we sought to extend these findings and characterize skilled learning, a more complex behavior known to be altered in Rett syndrome. Methods: We evaluated the acquisition and performance of auditory and motor function on two complex tasks in heterozygous female Mecp2 rats. Animals were trained to perform a speech discrimination task or a skilled forelimb reaching task. Results: Our results reveal that Mecp2 rats display slower acquisition and reduced performance on an auditory discrimination task than wild-type (WT) littermates. Similarly, Mecp2 rats exhibit impaired learning rates and worse performance on a skilled forelimb motor task compared to WT. Conclusions: Together, these findings illustrate novel deficits in skilled learning consistent with clinical manifestation of Rett syndrome and provide a framework for development of therapeutic strategies to improve these complex behaviors.

scholarly journals Motivation and Classroom Teaching in Geography

2013 ◽  
Vol 1 (3) ◽  
pp. 26-36
Author(s):  
Bethel T. Ababio
Keyword(s):  
Student Motivation ◽  
Teaching And Learning ◽  
Personal Relationships ◽  
Classroom Teaching ◽  
Classroom Situation ◽  
Specific Goal ◽  
Efficient Learning ◽  
Effective Use ◽  
Do So

Several factors influence the teaching and learning of geography in the classroom situation. Prominent among these factors is motivation. Motivation may be described as a state of arousal in which an individual wishes to achieve a specific goal and exerts effort to do so. In the classroom, efficient learning would be impossible if motivation was absent. But this appears to be the situation in many geography classes. There are classroom situations in which student motivation is at a minimum and in which learning is correspondingly slow. In such unmotivated classes, there are geography teachers who leave their students with half formed and hazy concepts; teachers who make no attempt to select teaching procedures that will be interesting to students; teachers who criticize students negatively rather than constructively; such classes are also characterized by strained personal relationships between students and their teachers. To address these worrying concerns in the geography classroom, this article is devoted to the discussion of principles, practices and specific suggestions aimed at enabling the geography teacher to make more effective use of motivation in classroom situations.

scholarly journals Deficits in skilled motor and auditory learning in a rat model of Rett syndrome

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Katherine S. Adcock ◽  
Abigail E. Blount ◽  
Robert A. Morrison ◽  
Amanda Alvarez-Dieppa ◽  
Michael P. Kilgard ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Discrimination Task ◽  
Neurodevelopmental Disorder ◽  
Motor Task ◽  
Speech Discrimination ◽  
Auditory Learning ◽  
Reaching Task ◽  
Developmental Regression ◽  
Learning Rates ◽  
And Performance

Abstract Background Rett syndrome is an X-linked neurodevelopmental disorder caused by a mutation in the gene MECP2. Individuals with Rett syndrome display developmental regression at an early age, and develop a range of motor, auditory, cognitive, and social impairments. Several studies have successfully modeled some aspects of dysfunction and Rett syndrome-like phenotypes in transgenic mouse and rat models bearing mutations in the MECP2 gene. Here, we sought to extend these findings and characterize skilled learning, a more complex behavior known to be altered in Rett syndrome. Methods We evaluated the acquisition and performance of auditory and motor function on two complex tasks in heterozygous female Mecp2 rats. Animals were trained to perform a speech discrimination task or a skilled forelimb reaching task. Results Our results reveal that Mecp2 rats display slower acquisition and reduced performance on an auditory discrimination task than wild-type (WT) littermates. Similarly, Mecp2 rats exhibit impaired learning rates and worse performance on a skilled forelimb motor task compared to WT. Conclusions Together, these findings illustrate novel deficits in skilled learning consistent with clinical manifestation of Rett syndrome and provide a framework for development of therapeutic strategies to improve these complex behaviors.

scholarly journals Deficits in Skilled Motor and Auditory Learning in a Rat Model of Rett Syndrome

2020 ◽  
Author(s):  
Katherine S. Adcock ◽  
Abigail E. Blount ◽  
Robert A. Morrison ◽  
Amanda Alvarez-Dieppa ◽  
Michael P. Kilgard ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Discrimination Task ◽  
Neurodevelopmental Disorder ◽  
Motor Task ◽  
Speech Discrimination ◽  
Auditory Learning ◽  
Reaching Task ◽  
Developmental Regression ◽  
Learning Rates ◽  
And Performance

Abstract Background Rett Syndrome is an X-linked neurodevelopmental disorder caused by a mutation in the gene MECP2 . Individuals with Rett Syndrome display developmental regression at an early age, and develop a range of motor, auditory, cognitive and social impairments. Several studies have successfully modeled some aspects of dysfunction and Rett Syndrome-like phenotypes in transgenic mouse and rat models bearing mutations in the MECP2 gene. Here, we sought to extend these findings and characterize skilled learning, a more complex behavior known to be altered in Rett syndrome. Methods We evaluated the acquisition and performance of auditory and motor function on two complex tasks in heterozygous female Mecp2 rats. Animals were trained to perform a speech discrimination task or a skilled forelimb reaching task. Results Our results reveal that Mecp2 rats display slower acquisition and reduced performance on an auditory discrimination task than wild-type (WT) littermates. Similarly, Mecp2 rats exhibit impaired learning rates and worse performance on a skilled forelimb motor task compared to WT. Conclusions Together, these findings illustrate novel deficits in skilled learning consistent with clinical manifestation of Rett syndrome and provide a framework for development of therapeutic strategies to improve these complex behaviors.

Thought, Choice, and Other Causes in Aristotle’s Account of Luck

Apeiron ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Emily Kress
Keyword(s):  
General Strategy ◽  
Practical Case ◽  
To Come ◽  
The Right ◽  
Do So

Abstract In Physics 2.4–6, Aristotle offers an account of things that happen “by luck” (ἀπὸ τύχης) and “spontaneously” (ἀπὸ τοῦ αὐτομάτου). Many of these things are what we might think of as “lucky breaks”: cases where things go well for us, even though we don’t expect them to. In Physics 2.5, Aristotle illustrates this idea with the case of a man who goes to the market for some reason unrelated to collecting a debt he is owed (197a17–8). While he is there, this man just so happens to run into his debtor and get his money back—which is what he “wanted” all along (196a4). This case has a number of features that have proved puzzling. Most notably, Aristotle seems to think that while “it happened accidentally to him to come and to do this for the sake of getting the money”, nevertheless the man “did not come for the sake of this”—though he “would have” (196b34–6). What must such a proceeding be like to be described in these ways? Physics 2.4–6 makes several important moves towards answering this question. One of them—among the earliest and seemingly a foundational one—is the claim that “for the sake of something are as many things as could be done by thought and by nature” (196b21–2). The aim of this paper is to identify the role that this claim plays in Aristotle’s account of spontaneous proceedings. It defends two main claims. First, Aristotle’s suggestion that spontaneous proceedings could be done by nature and by thought is the product of a more general strategy. His approach is to sketch an intuitive pattern of explanation for proceedings that happen for the sake of something in the ordinary—non-spontaneous—way, and then to try to extend that model to the case of things that do so spontaneously, preserving as much of it as possible. Applying this strategy reveals that whereas nature and thought in fact function as efficient causes of ordinary proceedings that are for the sake of something, this cannot be the case in spontaneous ones. Instead, nature and thought could function as their causes. Second, I argue that Aristotle’s implementation of this strategy is rooted in his account of causation and especially Physics 2.3’s list of “modes” (τρόποι) of causes. When he claims that spontaneous proceedings “could” be done by nature and by thought, he is saying that nature (in natural cases) and thought (in practical ones) are their efficient causes in capacity. In the practical case, spontaneous proceedings are caused by agents who have certain capacities, connected with their desires and abilities. In the right circumstances, these agents would actively exercise those capacities in acting for the sake of a given end.

scholarly journals The Effects of Motor Modularity on Performance, Learning, and Generalizability in Upper-Extremity Reaching: a Computational Analysis

2019 ◽  
Author(s):  
Mazen Al Borno ◽  
Jennifer L. Hicks ◽  
Scott L. Delp
Keyword(s):  
Upper Extremity ◽  
Realistic Model ◽  
Computational Time ◽  
Muscle Synergies ◽  
Performance Deficits ◽  
Reaching Task ◽  
Learning Rates ◽  
The Central Nervous System ◽  
The Rich ◽  
Low Dimensional

AbstractIt has been hypothesized that the central nervous system simplifies the production of movement by limiting motor commands to a small set of modules known as muscle synergies. Recently, investigators have questioned whether a low-dimensional controller can produce the rich and flexible behaviors seen in everyday movements. To study this issue, we implemented muscle synergies in a biomechanically realistic model of the human upper extremity and performed computational experiments to determine whether synergies introduced task performance deficits, facilitated the learning of movements, and generalized to different movements. We derived sets of synergies from the muscle excitations our dynamic optimizations computed for a nominal task (reaching in a plane). Then we compared the performance and learning rates of a controller that activated all muscles independently to controllers that activated the synergies derived from the nominal reaching task. We found that a controller based on synergies had errors within 1 cm of a full-dimensional controller and achieved faster learning rates (as estimated from computational time to converge). The synergy-based controllers could also accomplish new tasks–such as reaching to targets on a higher or lower plane, and starting from alternate initial poses–with average errors similar to a full-dimensional controller.

scholarly journals Deficits in Skilled Motor and Auditory Learning in a Rat Model of Rett Syndrome

2020 ◽  
Author(s):  
Katherine S. Adcock ◽  
Abigail E. Blount ◽  
Robert A. Morrison ◽  
Amanda Alvarez-Dieppa ◽  
Michael P. Kilgard ◽  
...  
Keyword(s):  
Rett Syndrome ◽  
Discrimination Task ◽  
Neurodevelopmental Disorder ◽  
Motor Task ◽  
Speech Discrimination ◽  
Auditory Learning ◽  
Reaching Task ◽  
Developmental Regression ◽  
Learning Rates ◽  
And Performance

Abstract Background Rett Syndrome is an X-linked neurodevelopmental disorder caused by a mutation in the gene MECP2 . Individuals with Rett Syndrome display developmental regression at an early age, and develop a range of motor, auditory, cognitive and social impairments. Several studies have successfully modeled some aspects of dysfunction and Rett Syndrome-like phenotypes in transgenic mouse and rat models bearing mutations in the MECP2 gene. Here, we sought to extend these findings and characterize skilled learning, a more complex behavior known to be altered in Rett syndrome. Methods We evaluated the acquisition and performance of auditory and motor function on two complex tasks in heterozygous female Mecp2 rats. Animals were trained to perform a speech discrimination task or a skilled forelimb reaching task. Results Our results reveal that Mecp2 rats display slower acquisition and reduced performance on an auditory discrimination task than wild-type (WT) littermates. Similarly, Mecp2 rats exhibit impaired learning rates and worse performance on a skilled forelimb motor task compared to WT. Conclusions Together, these findings illustrate novel deficits in skilled learning consistent with clinical manifestation of Rett syndrome and provide a framework for development of therapeutic strategies to improve these complex behaviors.

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