John P. Spencer - US grants

To interact successfully in the environment, people must remember the locations of important objects accurately enough to find these objects when they are no longer in view. Otherwise, keys, shoes, and hats would be lost forever in the clutter of the typical home or office. The majority of research investigating the characteristics of location memory has focused on WHAT people represent in memory. For instance, do people represent that a set of keys is two inches to the left of a computer, or do they represent that the keys are one arms-length away? Although what is represented is a fundamental question, this research will examine a different, but equally important question: HOW do people maintain location information in memory? This question is timely because recent studies with non-human primates have identified several brain regions that contribute to the maintenance of location information in memory. Thus, there is a growing understanding of how the brain keeps location information active in memory. Nevertheless, few studies with humans have interfaced with this emerging knowledge base. This research will establish a link between behavioral studies of how humans remember locations and the literature on brain function. Central to this research is how people use perceptual cues from second-to-second to help maintain information in memory. Evidence from a variety of studies suggests that people rely on visible reference axes, e.g., the edges of a table, the edges of a computer screen, to help them remember the locations of target objects. Use of such perceptual cues can help keep remembered information in the right ballpark (the keys are near the left edge of the table and not over by the computer). Nevertheless, there is a cost, in that memory is systematically distorted near reference axes. Specifically, when people are asked to reproduce the location of a hidden object, they exaggerate the distance between the reference axis and the actual location of the object. These memory errors are particularly informative because they increase in magnitude as memory delays increase. Thus, errors away from reference axes provide a window into the second-to-second processes that serve to maintain location information in memory. This research will test a mathematical model of these maintenance processes, a model that specifies how a network of neurons can give rise to the types of memory errors humans make. Nine experiments will test this model of how location memory works. The first five experiments will test specific predictions of the model. These experiments will establish whether people make the particular types of memory errors predicted by the model, and whether these errors do, in fact, result from the use of reference axes. The final four experiments will examine the generality of the model to novel situations. For instance, do adults make the same types of memory errors when they are forced to attend to non-target locations during a memory delay? When completed, this project will provide the first formal model of the processes that maintain location information in memory over short-term delays. This model and the associated empirical data may have broad implications. For instance, the model will provide insights into what cues most effectively maintain information in memory. This could lead to an informed re-structuring of the environment for people who have difficulty maintaining information in working memory, such as elderly participants and patients suffering from Alzheimer's Disease. The model could also predict what patterns of error are most likely when people are unskilled (e.g., early in development), and what processes might be most severely disrupted under conditions of stress or strain (e.g., sleep deprivation, impaired visual processing, brain injury).

DESCRIPTION (provided by applicant): To interact successfully with the local environment, people must maintain a "local map' of the locations of important nearby objects. This is one of the primary functions of spatial working memory. The majority of research investigating the characteristics of spatial working memory has focused on what people represent in memory. Although this is a fundamental question, the present study examines a different, but equally important question: how do people maintain location information in memory? This question is timely because recent studies have identified several brain regions that contribute to the maintenance of location information. Furthermore, studies have demonstrated that elderly participants and patients suffering from Alzheimer's Disease show deficits when the characteristics of a visual stimulus must be maintained in working memory over a delay. Evidence from a variety of studies suggests that people rely on visible reference axes -- the edges of a table, the edges of a computer screen -- to help them remember the locations of target objects. Use of such perceptual information can help stabilize memory. Nevertheless, there is a cost -- memory is systematically distorted near reference axes. Specifically, when people are asked to reproduce the location of a hidden object, they exaggerate the distance between the reference axis and the actual location of the object. These memory errors are particularly informative because they increase in magnitude as memory delays increase. Thus, errors away from reference axes may provide a window into the second-to-second processes the serve to maintain location information in working memory. Fourteen experiments will test a mathematical model of how information is maintained in spatial working memory with both child and adult participants. The first eight experiments test specific predictions of the model. The final seven experiments examine the generality of the model to situations in which a reaching response is not required and to situations that place demands on spatial selective attention. When completed, the proposed project will provide the first formal theory of spatial working memory.

The study of child development has always been organized around "big issues" and "grand" theoretical ideas. In this milieu, two new theoretical perspectives emerged in the 1990's - dynamic systems theory and connectionist approaches to development. According to both theories, children develop step-by-step; that is, each change in the child's ability sets the stage for the next developments. Importantly, this step-by-step process is not specified in advance by genes or "maturation"; rather, development emerges as each child finds his/her own unique pathway. This is natural because development is a product of many factors coming together to produce behavioral change - brain changes, bodily changes, environmental changes, etc. Although these two perspectives share many concepts, they have been applied to very different phenomena. For instance, dynamic systems theory has been used to explain changes in motor skills such as reaching, crawling, and walking, while connectionism has been used to explain the development of cognitive abilities such as language. As such, it is unclear exactly how these approaches relate to one another. Dr. John Spencer has organized a 3-day conference to bring together a set of core scholars affiliated with each approach to determine whether these are two separate theories of development or one grand theory. To sharpen this dialogue, speakers from a related viewpoint - developmental systems theory - will also participate, as will a second group of scholars with general expertise in developmental and cognitive psychology. In addition, there will be a large group of graduate students in attendance, funded in part by conference travel awards. An edited book summarizing results of the conference will be published by Oxford University Press.

The conference and published book are likely to make a major contribution to the field of developmental psychology in that they will clarify the relationship between two of the most promising new theories in the field. More broadly, results of this conference are likely to impact the well-being of children because grand theories of development shape how people think about children. These theories influence national policy, educational curricula, and parenting, forming a framework within which real children learn and grow. Thus, debate and discussion about these two new theoretical contenders - connectionism and dynamic systems theory - have the potential for far-reaching influences.

Abstract
Human activity and thought is embedded within and richly structured by the space around us. We have detailed knowledge of the objects that surround us-where they are, what they are, how they are arranged relative to one another. And we can easily remember the layout of objects in completely new situations, quickly learning which things go where. This grant investigates the dynamics of spatial cognition, that is, the time-dependent processes that underlie such coordinated spatial behaviors.
Spatial cognition has typically been studied as isolated parts-spatial perception, spatial memory, spatial attention, and so on. Consistent with this approach, neurophysiological evidence suggests a functional and anatomical segregation of the visual system into one neural pathway that represents spatial locations ("where") and another neural pathway that represents object property information ("what"). Critically, we know very little about how information in these two pathways is integrated, despite the fact that most behaviors rely on both spatial and object information.
The goal of this grant is to tackle the integration of "where" and "what" systems using a neurally-plausible theory of working memory, the Dynamic Neural Field Theory (DNFT). This theory captures how people hold information in working memory, how they use perceptual cues to keep memorized information accurate, and how long-term memories emerge from this mix. Critically, our new model specifies not just where objects are located, but what those objects are and how spatial and object information can be brought together to guide action. The research plan formalizes this new model and tests a set of critical predictions across 10 experiments.
The DNFT is the first theory of spatial cognition that integrates perception, working memory, and long-term memory in a neurally-plausible way that makes specific predictions about how people behave. As such, this project will advance our understanding of the processes that govern human activity in space-how people think about space, how people organize spatial activities, and the local "maps" of the world people bring with them from context to context. Such information could have a critical impact on how groups and individuals structure spaces to foster communication and lessen memory and attentional demands. Moreover, there is compelling evidence that deficits in where-what integration underlie the behavior problems prevalent in several mental health disorders. The DNFT takes an important step toward addressing both the behavioral and neural processes that likely underlie these behavioral disorders. The space around us has a profound effect on human thought and activity. The proposed research will move us closer to understanding this pervasive aspect of human and social dynamics.
The present work will advance two educational goals as well. First, the PI and co-PIs will establish an international graduate student exchange to foster the education of promising scholars in both the US and Germany. Second, funds from this grant will support a high school outreach program to expose AP calculus students to the application of mathematical models in "real world" science. Beyond these educational impacts, the proposed project will impact the general scholarly community through the publication of empirical and theoretical manuscripts and the creation of a web-based dynamic field simulator.

[unreadable] DESCRIPTION (provided by applicant): Humans are exceptionally good at remembering the layout of objects in a local workspace. The present proposal investigates the time-dependent processes that underlie this ability to quickly and flexibly form, maintain, and update such `cognitive maps'. A central challenge to understanding this ability is to understand how people integrate `where' with `what'. Neurophysiological evidence suggests a functional and anatomical segregation of the visual system into dorsal and ventral pathways that represent spatial location (`where') and object property information (`what'), respectively. Although a great deal of work has clarified the operation of these processing streams in isolation, much less is known about how spatial and non-spatial information is integrated. The goal of this grant is to develop and test a neurally- plausible theory of where-what integration. The research plan formalizes such a theory and tests specific predictions derived from its central concepts. Specific Aim 1 examines how people `bind' non-spatial features together to form object representations grounded in a world-centered spatial frame of reference. Specific Aim 2 examines the mechanisms that maintain object representations during short delays and detect changes in object features. Specific Aim 3 highlights the advantages of grounding `what' in `where': people can flexibly update working memory representations by coupling these representations to a real-time spatial system. Understanding the integration of `where' and `what' in a neurally-plausible way is critical for two reasons. First, there is compelling evidence that deficits in where-what integration underlie the behavior problems prevalent in several mental health disorders including ADHD, Williams Syndrome, Schizophrenia, and Alzheimer's/Dementia. Second, understanding the integration of dorsal and ventral pathways is a core requirement of any neurally-plausible theory that purports to link brain and behavior in an ecologically grounded way. Indeed, the real promise of our approach lies at the intersection of these themes: to develop a theory that can address both the behavioral and neural deficits that underlie specific mental health disorders. PUBLIC HEALTH RELEVANCE: The goal of this grant is to develop and test a neural theory of how people integrate information about where objects are located with memory for what the objects are. Achieving this goal will have broad implications for our understanding of mental health because deficits in `where-what' integration underlie the behavior problems in several mental health disorders including ADHD, Williams Syndrome, Schizophrenia, and Alzheimer's/Dementia. Understanding the integration of `where' and `what' is also a core requirement of any theory that purports to link brain and behavior in an ecologically grounded way. [unreadable] [unreadable] [unreadable]

This proposal requests NSF funding to support a summer school on Dynamic Field Theory and its applications to cognitive science, to be held in June 8-12 at the University of Iowa. Dynamic Field Theory provides a formal framework for thinking about embodied cognitive dynamics. The Summer School is organized so that students receive hands-on experience working with specific dynamic neural field models within their own area of expertise. The Summer School begins with an introduction to the central concepts of dynamical systems theory, and the mathematical and neurophysiological bases of dynamic field theory. Next, students will learn how activation dynamics in neural fields provide critical links to two central challenges in cognitive and developmental science: the integration of processes over multiple time scales and the origin of behavioral flexibility. The final lectures will focus on applications of the theory in different domains, from lower-level examples in the domains of motor control and robotics to higher-level domains including working memory and word learning. Lectures and course materials are freely available at the Summer School website: www.uiowa.edu/~icdls/dft-school/.

Abstract
This proposal requests NSF funding to support a summer school on Dynamic Field Theory and its applications to cognitive science, to be held in June 7-11, 2010 at the University of Iowa. Dynamic Field Theory provides a formal framework for thinking about embodied cognitive dynamics. The Summer School is organized so that students receive hands-on experience working with specific dynamic neural field models within their own area of expertise. The Summer School begins with an introduction to the central concepts of dynamical systems theory, and the mathematical and neurophysiological bases of dynamic field theory. Next, students will learn how activation dynamics in neural fields provide critical links to two central challenges in cognitive and developmental science: the integration of processes over multiple time scales and the origin of behavioral flexibility. The final lectures will focus on applications of the theory in different domains, from lower-level examples in the domains of motor control and robotics to higher-level domains including working memory and word learning. Lectures and course materials are freely available at the Summer School website: www.uiowa.edu/~icdls/dft-school/. In addition, students participate in an outreach program which brings an activity called "Overhead 'Bots" to 5-12 year old children from the local community. The activity is a fun way to illustrate the concepts of dynamics, embodied cognition, and robotics.

The goal of this project is to understand how the brain realizes the impressive flexibility that is a hallmark of human cognition. For example, adults can flexibly shift from conversing about current events, to feeding the cats, to cooking dinner, all without getting mixed up and cooking cat food as the main course. This ability is thought to rely on the actions and interactions of multiple brain areas. A central challenge in understanding cognitive flexibility is to understand how these brain networks change with learning and how they organize and re-organize "on-the-fly" depending on the situation. More generally, how does the brain keep track of events as they unfold but at the same time retain flexibility?

In this project, a multidisciplinary team of investigators will test a new theory of cognitive flexibility using computer modeling and functional neuroimaging data. The theory is implemented using dynamic neural fields -a specific type of neural network that can be simulated on a computer and that specifies how different areas of the cortex interact during complex tasks. Some cortical areas actively maintain neural patterns related to the lower-level details of what is happening, for instance, maintaining information about critical visual features of the pan, the items you are cooking for dinner, and so on. Other cortical areas modulate what these systems are up to. Critically, "higher-level" systems do not need to understand all the details of what is going on. They just need to help decide which general patterns of information are important in the context. It is the dialog between these different neural patterns that makes cognition flexible.

The success of this project would have far-reaching effects. The ability to modulate behavior in context-specific ways is a central achievement that impacts language skills, mathematical abilities, school and work performance, and IQ. Moreover, deficits in cognitive flexibility and so-called executive functions underlie different forms of psychopathology, such as schizophrenia, as well as many of the challenges faced by aging adults. The investigators have also established a collaboration with the Iowa Children's Museum where they will work with museum staff to design an interactive display around the theme of "Brain Play," in which children construct simple solar-powered robots that embody how the brain and body realize flexibility.

This workshop will bring together scientists, philosophers, administrators, community organizers, policy makers, and legislators to examine civic science. The main goals are to delineate what civic science is, to specify how it differs from citizen science and activist street science, and to generate best practices for civic science. The proposers also hope to develop strategies to impact policy discussions and professional education, and to make some headway towards shifting the national conversation about the role of science in society.


This work should help foster the collective capacities of scientists and non-scientists to come together to solve real-world problems in a democratic society. A white paper will be produced

The Directorate of Social, Behavioral and Economic Sciences offers postdoctoral research fellowships to provide opportunities for recent doctoral graduates to obtain additional training, to gain research experience under the sponsorship of established scientists, and to broaden their scientific horizons beyond their undergraduate and graduate training. Postdoctoral fellowships are further designed to assist new scientists to direct their research efforts across traditional disciplinary lines and to avail themselves of unique research resources, sites, and facilities, including at foreign locations. This postdoctoral fellowship supports a rising scientist in the interdisciplinary area of speech production, cognitive science and neurocomputational modeling. Speech production is a complex skill that hinges on the real-time integration of cognitive and sensorimotor processes. Contemporary models of speech production pay little attention to salient cognitive processes such as intention, attention, and awareness. One way to further basic understanding of the critical link between cognitive and sensorimotor systems during speech production is to examine typically and atypically developing systems. This project investigates stuttering, a neurodevelopmental speech disorder, by leveraging the well-known phenomenon of anticipation. Anticipation refers to the a priori sense a speaker has that upcoming speech will be stuttered. Examining anticipation and speech behavior through the lens of a pathological system (i.e., a stuttering system) will ultimately shed light on a basic question in speech research?how cognition, perception, and action underlie speech production and its development. Findings from this work will also have real-world applicability as they will support the development of tailored diagnostic and clinical procedures for those who experience stuttering and its related social and emotional consequences.

This innovative work combines computational modeling and empirical investigation to develop and test a model of stuttered speech production. It applies principles of Dynamic Field Theory (DFT), an established neurocomputational approach to modeling that formalizes the relationship between cognitive and sensorimotor systems. DFT has benefitted from recent advances in cognitive science, mathematical biology, motor control, developmental psychology, and theoretical neuroscience, highlighting the multidisciplinary nature of this work. Critically, DFT integrates real-time processes with processes of learning and development. Thus, the framework is poised to contribute to an understanding of the relationship between in-the-moment speech behaviors and their cognitive underpinnings that often occur over longer timescales, and are more difficult to observe. The experimental component of this project employs optical tracking and functional near-infrared spectroscopy, allowing for direct comparisons at behavioral, kinematic, and neurophysiological levels. Specific aims of this project include: (1) extending a preliminary DFT-based model of typical speech production, as well as attempting to break the model in ways that are reflective of stuttering; and (2) testing the model empirically in a cross-sectional study that examines the development of anticipation of stuttering across the life span. This proposal is also supported by the NSF EPSCoR.

? DESCRIPTION (provided by applicant): Working memory has been dubbed the heart of intelligent behavior, and a core property of this critical cognitive system is its highly limited capacity. Working memory capacity limitations are reliably associated with individual differences in many basic forms of cognition (e.g., language and mathematical abilities), and working memory deficits have been observed in at-risk populations, including children diagnosed with attention-deficit/hyperactivity disorder, autism, and children born preterm. Given these influences, understanding the development of working memory capacity limits has broad implications and may be critical to intervention efforts with atypically developing children. This grant focuses on the development of a central type of working memory called visual working memory (VWM). VWM plays a key role in much of visual cognition, comparing percepts that cannot be simultaneously viewed and identifying changes in the world when they occur. Research has shown that VWM develops dramatically between infancy and 5 years old, and a recent dynamic neural field (DNF) model of VWM has formalized a candidate neural mechanism for how VWM capacity changes in early development and why such changes vary across tasks. A key goal of the grant is to test this theoretical account at neural and behavioral levels. In particular, we will conduct an accelerated longitudinal study from 6 months to 4.5 years. At each age, children will complete two functional neuroimaging sessions and a structural neuroimaging session. We will use these data to examine: (1) whether the DNF model captures individual developmental trajectories in VWM performance from 6 months to 4.5 years; (2) whether the DNF model predicts functional changes in the VWM brain network in early development; and (3) whether changes in DNF parameters over development are explained by localized changes in myelin content within the VWM network. Results from this grant will set the stage for extensions of our approach to examine longitudinal changes in at-risk populations. This work will also foster an innovative approach to individualized interventions guided by a neural process model of VWM that speaks to individual differences in both brain and behavior.