2011 — 2012 |
Shomstein, Sarah Svetlana |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Cortical Responses, and Their Modification, With Limited Attentional Contribution @ George Washington University
DESCRIPTION (provided by applicant): Efficiently selecting a relevant subset of sensory information for further processing is a fundamental mechanism that is central to a whole host of cognitive functions. This process of perceptual selectivity, also referred to as 'attention', plays a key role in determining what we perceive. A large body of evidence, acquired over the last 5 years from neurophysiology, functional imaging and behavioral investigations, has allowed researchers novel insights into the psychological and neural mechanisms mediating attentional selection. Although we currently have at our disposal the unprecedented means for elucidating brain-behavior correspondences in the domain of visual attention, far more questions and contradictions have emerged than have answers. A greater degree of specificity and fine-grained analysis at both the behavioral and the brain level is now required to advance further our understanding of visual attention, specifically, and visual cognition, more generally. The specific aims of the current project include (1) evaluate the consequences that interhemispheric attentional imbalance has on sensory signals elicited in early and late visual cortices of the two hemispheres;and (2) investigate the psychological and neural consequences of a rehabilitation procedure aimed at recovery from this hemispheric imbalance. The results of this project will significantly advance our understanding of how attention influences perception in the normal functioning neural system and in patients with visuo-spatial neglect (a neurological disorder). Gaining a more fine-grained understanding of attentional selection is ever more important given that various types of psychiatric as well as neurological disorders co-occur with attentional dysfunction (ADHD, schizophrenia, Balint's syndrome, visuo- spatial neglect, autism) and affect many individuals - male and females of all age groups, socioeconomic strata and ethnicities. In summary, the results from this project may have broad application by providing further understanding into the neural mechanism of attentional selectivity as well as by fostering insights into possible neuro-rehabilitative techniques that might be used to ameliorate the behavioral deficits associated with attentional disorders. PUBLIC HEALTH RELEVANCE: Characterizing the effect and impact of attention on sensory responses promises to improve significantly our understanding of neural, and some psychiatric, disorders that affect attention orienting (such as hemispatial neglect, Balint's syndrome, attention deficit hyperactivity disorder, schizophrenia, and autism). Here, we investigate hemispatial neglect, a neurological deficit most commonly present after stroke, a condition that affects at least 500,000 Americans every year (according to the American Heart Association). A major contribution from this study will be both an enhanced understanding of attentional dysfunction in hemispatial neglect, and also a clear mechanistic explanation of the effects of a neuro-rehabilitative tool that may be used to aid the recovery from a debilitating neurological disorder.
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0.958 |
2011 — 2015 |
Shomstein, Sarah |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Uncertainty Reduction: the Guiding Principle of Attentional Allocation @ George Washington University
Attention is a central process in cognition. When people search through the environment for information relevant to their current goal, they are selectively processing perceptual information. Crucial to our understanding of attentional selection is determining what guides this selection. Until recently it has been observed that spatial locations are important for attentional guidance. However, recent evidence suggests that under some circumstances objects, not spatial locations, guide attentional selection. The full understanding of why under some circumstances such guidance is possible has remained elusive. This program of research introduces and tests a new unifying framework, uncertainty reduction, within which to examine factors that influence object-based attentional guidance. The generality of this framework is investigated, in several different paradigms, by systematically testing its predictive powers in two domains of uncertainty: internal uncertainty reduction as manipulated by reward and external uncertainty reduction as manipulated by varying the scope of attentional set. In order to understand uncertainty reduction and its effects on object-based attentional guidance, behavioral profiles as well as the neural underpinnings of this mechanism are examined. Whether reading a book in the peace and quiet of your living room or driving a car in traffic, the ability to pay attention to important aspects of the environment is an integral part of our lives and, ultimately, is crucial to our success and survival. A better understanding of critical factors that determine how attentional selection is deployed is important to diverse fields such as the design of interactive and ergonomic panels and enhanced training programs across multiple industries, ranging from training drivers and machine operators to security personnel (e.g., airport baggage screeners) to neurologists reading X-rays for evidence of cancer.
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1 |
2015 — 2018 |
Shomstein, Sarah |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Intrusive Effects of Task Irrelevant Semantic Information On Visual Selective Attention @ George Washington University
Selective attention involves the remarkable ability to dynamically search for and select information from the environment that is relevant for the current goal. How the human cognitive system achieves this is a fundamental question in cognitive science. Given that what humans consciously perceive will, ultimately, depend on where attention is directed, understanding attentional mechanisms is an important first step toward revealing the neural mechanisms that support conscious awareness. It has long been established that physical features, such as spatial location or object appearance, can guide attentional selection in a spatial task. These researchers will examine the extent to which attention can be inadvertently grabbed by a visual item that is irrelevant to the spatial-orienting task at hand if that item happens to be semantically related to something recently experienced. The research team will investigate hypotheses regarding the underlying mechanism by which this type of attentional intrusion occurs during the process of trying to visually locate something. To further understanding of the basic mechanism, the research team will also use neuroimaging to examine at what neural stage in the visual system this intrusion effect takes place. Understanding what grabs visual attention and why could have important practical applications, such as better designing dynamic, interactive visual displays on devices such as tablets, smart phones, or computers.
The proposed research project aims to test a set of novel predictions regarding the influence of high-level properties of a scene to attentional selection. A major goal is to rigorously test the hypothesis that task-irrelevant semantic information constrains attentional selection by directly acting on space- and object-based representations: task-irrelevant objects that semantically relate to something seen recently are more likely to be attended. Predictions will be tested using real-world scenes, and by utilizing real-world objects. In addition to the rigorous behavioral experiments aimed at understanding the mechanism by which task-irrelevant but semantically primed stimuli exert their intrusive effects on attention, the researchers will use neuroimaging methodology to examine hypotheses regarding at what stage in the human visual system the effects occur.
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1 |
2019 — 2022 |
Shomstein, Sarah |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Guidance of Attention by Task-Irrelevant Information @ George Washington University
Attentional selection is a mechanism by which sensory information that makes up our environment is selected for further, detailed, and more efficient processing. Given that attended information is privileged by the brain, understanding and predicting what information is granted access to brain processing becomes an important endeavor. It has been argued that salient events (those that are very different from the surrounding environment) as well as information that is related to the current goal (i.e., task-relevant) are granted such access. The current work aims to extend this arguably simple notion of attentional orienting, to test the hypothesis that attentional selection can depend on may factors other than salience and task relevance. A better understanding of critical factors that determine how attentional selection is distributed in a scene could be used in various applied fields such as: design of interactive and ergonomic panels (e.g., car dashboards, instrumental panels, airplane cockpits, air traffic control monitors); enhanced training programs across multiple industries ranging from training drivers and machine operators to security personnel (e.g., airport baggage screeners) to neurologists reading X-rays for evidence of cancer; and developing new beneficial rehabilitative programs for persons suffering from various attentional disorders (Attention Deficit Disorder, visuo-spatial neglect, etc.).
Given a critical mass of knowledge acquired on how salient and task-relevant aspects of the scene contribute to attentional allocation, the time is ripe to probe various ways in which task-irrelevant properties of the environment constrain attentional allocation. The proposed research program tests a set of novel predictions regarding the influence of task-irrelevant properties of the scene to attentional selection. Our goal is to rigorously test the hypothesis that task-irrelevant information (such as semantics, affordances, size, diagnosticity), constrains attentional selection by directly acting on spatial and object representations. While extensive past research has demonstrated that relevant information constrains attentional selection, we ask a more fundamental question whether different types of task-irrelevant information impinge on attentional control even when not directly relevant to the current goal. Predictions will be tested in real world scenes, and by utilizing real world objects. Both, behavioral profile (with the use of various psychophysics and eye-movement techniques) as well as the neural underpinnings of this mechanism (by employing neuroimaging techniques), will be examined.
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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1 |
2020 — 2023 |
Shomstein, Sarah Kravitz, Dwight |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Neural Dynamics Underlying Working Memory Maintenance @ George Washington University
Working memory, the ability to maintain information in mind even when that information is no longer perceptually available, is a fundamental cognitive ability. The mechanism allows us to efficiently apply prior knowledge to the processing of the current context; enabling complex decision-making and guiding attention towards the most relevant features of the environment. While the link between visual working memory (VWM) and attention is well studied, its direct relation to perceptual processing is relatively less clear. This project will leverage the known properties of the neural substrate that supports VWM, to investigate the interaction between what is held in mind and how the mind interprets visual stimuli. The project will identify the time course of this interaction, to understand how content maintained in VWM decays over time. Neural stimulation will then characterize the causal contribution, of cortical areas which support perception, to the maintenance of information in working memory. A better understanding of the mechanisms underlying VWM can inform the design of interactive displays (car dashboards and air traffic controls, for example), and can improve training for numerous professions (such as airport baggage screeners and radiologists).
Recent neurophysiological findings, showing that VWM recruits sensorimotor cortical areas, afford a unique opportunity to generate behavioral predictions about this complex and critical cognitive process. This proposal leverages the known neurophysiological properties of sensorimotor areas (such as tuning curves and retinotopy) to generate behavioral predictions about VWM maintenance. First, if the same circuits are utilized by VWM and perception, then each process should interfere with the other. Further, the strength of these effects should scale with the similarity between the maintained and current stimulus, dependent on known visual tuning properties (such as orientation, motion direction, and face spaces). Second, maintained information should decay over time, having less of an effect on perception and becoming more prone to interference, which challenges some models of VWM. Third, initiation and maintenance of VWM depends on dynamics between prefrontal and perceptual cortices. Transcranial magnetic stimulation will be used to investigate the causal interaction between prefrontal and perceptual areas. The proposed research will provide novel, causal, and fundamental insights into how the brain enables and constrains VWM.
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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