Robert Sekuler - US grants

Although the aged suffer a disproportionate share of the handicaps of impaired vision, relatively little is known about the real character of visual perceptual losses with age. This project takes a developmental approach to visual perception, emphasing spatial and temporal information processing in the last half of the life-span. The project has a triplex structure. In one part, evaluation of spatial vision will be made using two techniques, including measurements with interference fringes generated directly on the retina. Since these targets are little affected by the eye's optics, we can use responses to the targets to estimate the observer's neural response, unaffected by optical factors. In addition, attempts will be made to correlate 1) ophthalmological examination of the older observers' retinas and 2) assessment of contrast sensitivity using spatially-localized targets with band-limited spatial frequency content. In a second part of the project, life-span changes in response to temporal modulation of targets will be measured. Normative data on smooth-pursuit eye movements and stability of fixation will be obtained from normal, healthy older observers. A subsidiary aim is to characterize the nature of the change in temporal processing with age. The third position of the proposal attempts to enhance the ability of older observers to make use of available sensory information, applying a newly developed perceptual learning paradigm. Finally, the preceding observations will be used to predict how older observers' performance in detection and discrimination of targets in displays containing complex targets of known spatial frequency content and contrasts.

[unreadable] DESCRIPTION (provided by applicant): Cooperation between vision and cognition enables humans to interact effectively with objects in the world. Despite its clear importance, far too little is known about one crucial component of these cooperative interactions: visual memory. The project will synthesize concepts and techniques drawn from vision research and from memory research, generating a coherent framework for understanding short-term visual memory, particularly episodic recognition memory. The project's empirical component uses variants of the Sternberg paradigm to assess episodic recognition for stimuli with known similarity relations. These stimuli, 2-dimensional textures created by linearly summing sinusoidal gratings and synthetic human faces, are not ordinarily used to explore memory. Because inter-stimulus similarities are central to theories of cognition, including theories of visual cognition, the ability to manipulate similarity relations among stimuli affords important advantages in research and modeling. [unreadable] [unreadable] To integrate vision and memory research, the project exploits a variety of empirical and modeling tools, including a mathematical model called NEMO, for Noisy-Exemplar Model. In preliminary experiments, NEMO has been applied successfully to recognition results averaged across test subjects. In order to pursue the project's long-term goal of understanding recognition performance by individual subjects on individual sets of stimulus items, NEMO will be evaluated relative to other alternative models. To take account of individual differences in vision, memory test stimuli will be scaled according to each subject's visual capacity. This should produce more direct assays of memory per se, including assays of any important individual differences in memory function. [unreadable] [unreadable]

A great deal of important human activity requires navigating and otherwise using physical spaces. Human spatial behavior, individual and collective, depends on the structure of the environment, the structure and content of cognitive representations of the environment (mental maps), individual and group goals, and interactions among individuals, groups, and crowds. As a result, human spatial behavior needs to be studied by considering all these aspects together; to do this requires a multidisciplinary effort. The proposed research brings together a team of researchers representing diverse disciplines of computation, psychology, and mathematics into an integrated program that will address human individual and collective use of physical space.
This project's multidisciplinary effort uses the tools of cognitive science, computational modeling, and mathematical analysis of collective behavior to study the dynamics of human spatial behavior. The project's goals are as follows:
1) To understand how individuals develop cognitive maps of complex environments in real-world situations that include rich spatial interactions with other people, individually and in groups;
2) To examine how cognitive maps influence the behavior of groups in high-density crowd conditions, and to develop the cognitive foundations for models of pedestrian dynamics and emergency evacuations;
3) To forge a mathematical link between microscopic (small scale) and macroscopic (large scale) models of adaptive human social behavior in spatial tasks.
The research program will develop novel cognitive map-driven models that will include the shared spatial information that individual people derive from social interactions. The models will be used to improve simulations of individuals and crowds, and provide a basis for mathematical analysis of collective spatial behavior dynamics. Validation and evaluation will exploit virtual reality technology, computer simulations of crowd behavior, and people's behavior in real environments. Through partnerships with two museums, the team will be working with real-world situations whose relevance to societal needs includes the design of emergency evacuation systems, automated detection of anomalies in large spaces and crowds, and the development of complex but human-friendly environments. The generation, validation, and free dissemination of powerful predictive models that will be developed will allow architects, planners, and developers of public spaces to design and/or modify public venues so as to optimize their navigability and safety. Finally, a comprehensive program of education, outreach, and dissemination will serve a broad audience of graduate and undergraduate students, inner-city K-12 students and teachers, and the general public will accompany the research.

DESCRIPTION (provided by applicant): Funds are requested to support three trainees per year over a five year period for training in the interface of behavioral and biomedical sciences. The core training faculty are from the Psychology Department and Neuroscience Program at Brandeis University. Affiliated faculty are from the Brandeis Life Sciences and adjunct faculty are from collaborating laboratories in the Greater Boston area. The faculty of this training program are firmly committed to educating students to study human behavioral health and development in terms of multi-directional, dynamic interactions among the biological building blocks of the body and brain and the emergent properties of whole individuals and groups of individuals. The training program we propose will be implemented within a Psychology Ph.D. program with strong, existing, intra- and inter-disciplinary research training, course work, and extra-curricular activities. Students in the training program will be required to fulfill the following requirements: 1) engage in rotations and research projects co-mentored by one or more faculty working in both psychological and biomedical disciplines; 2) take courses from menus of psychological, biomedical, and general quantitative categories; 3) attend a variety of integrative proseminars and small and large group colloquium/discussion series; 4) participate in short courses during the academic year and the summer designed to promote unity and to provide advanced training in biomedical or computational techniques. Non-trainee Ph.D. students will also be encouraged to fulfill these requirements. Full participation of Psychology students in biomedical laboratories is a challenge which will be met by systematic introduction of these curricular elements as well as by selection of qualified candidates. The adherence to and evaluation of the training program will be ensured by 1) annual internal reviews by the full core faculty of students' fulfillment of their goals as set out in a contract co-developed with the mentors; 2) annual reviews of the core faculty's guardianship by an internal steering committee and an external review committee; 3) feedback from students currently in the program and students who have graduated. Our general approach to recruitment of students will be through direct outreach and networking. To recruit and retain minority students, we will build upon the successful methods of our colleagues who are directing successful training grants in Psychology and Life Sciences at Brandeis Relevance: Integration of behavioral and biomedical sciences is essential for generating new knowledge about human mental health and disease. Training a new generation of scholars who have command of psychological, behavioral, and biomedical conceptual and methodological tools will help promote health and prevent and treat psychological and physical disorders

DESCRIPTION (provided by applicant): Perception and memory are central to the ordinary but important activities of everyday life. When cooperative interactions between the two processes are undermined by genetic or acquired disorder, by drugs of abuse, by inattention, or by age-related changes, the quality of cognitive life suffers. The project's long-term goal is the synthesis of concepts, insights and methods of memory research and ones from sensory research to produce a powerful, coherent framework for understanding cognition. The project's stimulus-oriented approach exploits careful design and control over stimuli, including techniques that minimize the impact of individual differences in perception. The project spans diverse stimulus classes: Gabors, spectro-temporally complex sounds, synthetic faces, parameterized 3D objects, and names. Aim One reveals how study item homogeneity influences item recognition. Comparing alternative accounts, the Aim dissects the route by which homogeneity is evaluated, and the origin of its influence. Thus, the Aim characterizes completely an important, recently-discovered powerful influence on recognition. With sets of comparable auditory and visual stimuli, Aim Two focuses on attentional selectivity by evaluating the impact of task-irrelevant information from different stimulus dimensions. The Aim identifies the mechanism(s) by which task-irrelevant information influences or fails to influence memory, and defines the way that task-relevant and task-irrelevant information is integrated. Guided by a summed-similarity model of associative recognition, Aim Three exploits carefully-controlled name-face stimulus pairs. Innovations include the control of stimulus similarity and homogeneity for both members of each name-face pair, which makes it possible to define the way that associative memory integrates both sources of information. Aim Four synthesizes NEMO, a global-matching model for item-recognition, with the Temporal Context Model (TCM). TCM describes how a rememberer's representation context evolves as new information is encountered. This synthesis yields a sophisticated, context-sensitive, stimulus-oriented account of item and associative recognition. This innovative model, C-NEMo, clarifies temporal information's contribution to recent effects and proactive interference. Also, by incorporating a drift-diffusion framework for choice reaction times, C-NEMo builds both speed and accuracy measures into our stimulus-oriented approach to memory. PUBLIC HEALTH RELEVANCE: Perception and memory are central to the cognitive activities that determine a person's quality of life. When their cooperative interactions are undermined by genetic or acquired disorder, by drugs of abuse, or by trauma- or age-related changes in the brain or sensory organs, everyday activities are restricted, and quality of life is diminished. This project contributes to the understanding of the mutually-reinforcing interactions between memory and perception, which are required for the development of sensitive assessment tools and effective interventions that are tailored to the needs of particular individuals.

CELEST seeks to understand the fundamental processes that underlie human learning by studying dynamic interactions within and among brain regions. Interdisciplinary research teams study how the brain learns to (1) plan: to make decisions for appropriate actions based on assessment of risks and potential rewards in a given situation, (2) explore: to perform planned actions to move about familiar and unfamiliar environments, (3) communicate: to use noisy and incomplete sensory information to interact effectively with other agents and objects in the world, and (4) remember: to encode and guide retrieval of information to achieve goals. CELEST is a multi-faceted collaboration that focuses the efforts of scientific and educational teams led by 15 senior scientists at four Boston-area universities. CELEST combines undergraduate and graduate training in interdisciplinary research that combines experimental cognitive neuroscience with quantitative behavioral and brain modeling of normal and abnormal learning during perception, cognition, emotion, and action.

Broader impacts: CELEST transfers the results of basic research on learning to undergraduate and graduate courses. This is achieved through its ongoing development of course materials for the new undergraduate neuroscience major at Boston University, and through electronic dissemination on the CELEST web site. Outreach to the undergraduate neuroscience community also occurs by means of a one-day CELEST workshop and related workbook about the cognitive basis of successful learning strategies. A number of CELEST programs are targeted at increasing opportunities for groups underrepresented in science to participate in its innovative curriculum and research initiatives. These include graduate fellowships, summer internships for faculty from minority-serving institutions, a ten-week summer program for undergraduates from underrepresented groups to work in CELEST faculty labs, and a week-long summer workshop to introduce undergraduates to the interplay of modeling and experimental techniques in cognitive neuroscience. Center added value: By bringing together distinct scientific communities that traditionally employ different practices and techniques, CELEST interdisciplinary science is changing the way we understand how the brain learns, and how different parts of the brain interact with each other during learning. Through collaboration with industrial partners, including the development and transfer of large-scale neuromorphic engineering and technological algorithms to industry and government laboratories, CELEST facilitates research for practical applications that cannot be supported by conventional single-investigator grants. CELEST faculty, postdocs, and students are playing increasingly important roles in communicating with non-specialists through many activities including blogs, workshops, and presentations to secondary school audiences. The integration of CELEST research and education is accomplished through the development of innovative curriculum materials based upon mathematical and computational models of mind and brain. through electronic and personal presentations to a variety of audiences, and through sponsorship of scientific conferences and workshops.