2009 — 2011 |
Taylor, Jordan A |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Neural Correlates of Strategic Control and Recalibration During Motor Learning @ University of California Berkeley
DESCRIPTION (provided by applicant): Learning is a remarkable process that enriches our lives by allowing us to rapidly acquire new skills, interact with novel tools and environments, and maintain memories of those experiences. Across a broad range of motor tasks, humans show a stereotypical learning function: an initial rapid decrease in errors followed by a slower, gradual reduction in error. It has been hypothesized that this learning curve reflects the operation of two processes, one based on strategic control and a second involving sensorimotor recalibration. By this view, strategic control, when available, quickly reduces large errors during the initial phase of learning. The sensorimotor recalibration operates with a slower time constant to gradually reduce errors throughout learning. Our first experiment will use a visuomotor adaptation task in which errors are either introduced abruptly or gradually. The former should engage both processes;for the latter, learning will be restricted to the sensorimotor recalibration process. Using a model-based approach, within-hand generalization and between-hand transfer will be used to identify the reference frame underlying the new sensorimotor mapping under these two processes of learning. A second series of experiments will examine the contribution of the dorsolateral prefrontal cortex to motor learning through its role in the strategic control process. Neuroimaging and patient research will be used to explore this question. Taken together, the experiments will aid in determining both the computational processes and neural circuits underlying motor learning. Stroke and neural disease can lead to a profound loss of motor ability, significantly impairing daily function. The N.I.H. identified the need to develop novel training methods to restore function in neurologically disabled individuals in its report "Neuroscience in the New Millennium." This project aims at examining how two different processes, reliant on distinct neural circuits, contribute to motor learning. These processes may be important for designing rehabilitation programs that are tailored to exploit learning and control systems that remain functional.
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0.951 |
2013 — 2017 |
Taylor, Jordan A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
A Model System to Study the Interaction of Multiple Processes For Motor Learning
DESCRIPTION (provided by applicant): Humans possess a remarkable ability to learn motor tasks very quickly. Recent findings are beginning to discover that this ability is supported by multiple learning systems, each with their unique computational features. The goal of this research proposal is to characterize these learning processes at a computational and neural systems level. The signatures of at least three separate learning mechanisms have been identified. Reinforcement learning can relate task success with a particular action to better guide selection among competing action alternatives. A forward model can learn to make predictions about the sensory consequences of a selected action to improve motor execution. While these two processes are capable of refining performance, one based on reinforcement and the other from movement error, they entail a relatively slow, gradual process requiring extensive practice. A striking feature of human competence is the ability to employ explicit strategies that can facilitate learning at a much faster time scale. We hypothesize that these three processes are dependent on distinct neural circuits that can operate concurrently during a motor learning task. Each may operate with a significant degree of independence, yet they can, in certain circumstances, interact to converge of a common learning solution. We will exploit a simple learning task involving a visuomotor rotation to parametrically manipulate the relative contribution of these processes to motor learning. We propose that changes in task conceptualization and feedback are critical in determining the relative engagement of these processes. Empirical tests and computational modeling will provide a rigorous analysis of these hypotheses and to develop a process-based account of motor learning. The neuroanatomical substrates of these processes will be explored by testing neurological populations with degenerative disorders of the cerebellum or basal ganglia, and patients with cortical lesions affecting prefrontal regions. We assume that reinforcement learning, forward model adaptation, and strategy-based control are likely operative in nearly all motor learning tasks, but their individual contribution to learning has largely been overlooked. If learning is the weighted contribution of these processes, then differences in task information as well as individual differences in the exploitation of this information will influence the relative contribution to learning, even when the basic task remains unchanged. Ultimately, understanding how multiple systems contribute to learning should lead to the development of optimal training protocols either designed to target impaired systems or bias performance to rely on systems that are relatively intact.
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1 |
2018 — 2020 |
Taylor, Jordan |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Eager: An Exploration of a Psychological Space For Human Motor Generalization
While we routinely perform similar actions, we can never repeat any single action in precisely the same way. This is because we are constantly adapting our movements to compensate for changes in the state of the body (e.g., muscle fatigue) and world (e.g., a slippery sidewalk). Thus, each new action can be thought of as a form of generalization based on previous actions. Current theories seeking to explain the pattern of generalization rest on the idea that the brain's representation of motor behaviors is rooted in the physical features of movement, such as in the muscles and joints involved. This EArly-concept Grant for Exploratory Research (EAGER) project takes an alternate approach to consider more psychological aspects of motor behavior - such as whether an individual thinks that the goal of two given actions is the same and consequently the individual believes they should behave in the same way. Exploring the possibility that generalization may be governed by representations rooted in a psychological dimension will lead to a more comprehensive theory of generalization and greater effectiveness of practical applications. Modern society includes many tools and digital devices that people learn and interact with. Principles gleaned from this project will inform better design of tools that speed user learning by leveraging generalization of previously existing skills. Additionally, results of this work could optimize neurorehabilitation protocols for patients of stroke and other causes of loss of motor ability.
Approaches from the fields of motor control and cognitive psychology will be used to determine if the pattern of human motor generalization is better characterized by representations in a psychological space. First, to gain insight into psychological factors, participants will be asked to judge the perceptual and subjective similarity between two movements in various task configurations, which are common to traditional studies of motor generalization. Participants will then experience a standard sensorimotor learning task, the visuomotor rotation task, to determine how their judgments of psychological similarity predict how they generalize learning in one region of space to new regions of space. Correlations between the pattern of similarity judgments and the pattern of motor generalization will provide the first step toward establishing the influence of psychological factors on generalization. Next, the exploration of psychological factors will be deepened by determining if broader conceptual assumptions regarding the goals of the task govern the pattern of generalization. To test this idea, participants' knowledge of tool functions will be used to define a psychological similarity space. Here, participants will categorize various tools in terms of similarity and multidimensional scaling techniques will be employed to determine a distance metric between these tools in a psychological space. Participants will then train to move with these tools in the visuomotor rotation task to determine the extent to which generalization between tools is defined by their relative distance in a psychological space. Critically, throughout the project, the physical aspects of these movements will be controlled, such that any changes to the pattern of generalization will provide evidence in support of a more psychological representation underlying generalization. If successful, these studies will lead to a more comprehensive theory of human motor generalization, one that accounts not only for how the mind interacts with motor function in the manipulation of tools, but also how tool function may shape and influence mind and motor function.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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0.915 |