Working memory plays a central role in cognitive processing, and an understanding of working memory is essential if we are to understand simple cognitive tasks such as retrieving a fact from memory, complex cognitive tasks such as cooking a meal, and psychopathologies that involve impaired cognition such as schizophrenia. The proposed research seeks to further our understanding of the visual storage component of the working memory system by means of a combination of traditional cognitive methods, psychophysical procedures adapted from vision research, computational simulations of explicit models, and human electrophysiological recordings (ERPs). This project will focus on four fundamental questions about the nature of visual working memory representations and the processes that create those representations. First, we will explore how the multiple features of an object are bound together in working memory, testing the hypothesis that bound objects are the fundamental units of visual working memory storage. Second, we will determine whether visual working memory consists of a small set of discrete, fixed-resolution representations or a potentially large set of variable-resolution representations. Third, we will ask whether working memory representations consist of structured sets of basic features or activations of potentially rich long-term memory representations (or both). Finally, we will examine the processes that transform transient and fragile perceptual representations into durable working memory representations that can survive the passage time and the perception of new stimuli. These issues will be addressed at the cognitive level, but they will also be linked to an explicit hypothesis about the neural mechanisms of working memory storage. The general goal of this project is to provide a deeper understanding of the most fundamental aspects of visual working memory, pushing basic science research on working memory to the next level. At the same time, the methods and findings of this project will provide the backbone for our laboratory's ongoing program of translational research on schizophrenia. Impairments in working memory are a key component of a spectrum of severe and pervasive cognitive dysfunctions in schizophrenia;these treatment-refractory cognitive impairments are largely responsible for the functional disability that is characteristic of the illness. However, it has been difficult to precisely characterize the nature of the working memory impairment in schizophrenia with the psychometric methods usually used in clinical research. This makes it difficult to define specific cognitive targets for new treatments or to provide a precise assessment of the effectiveness of these treatments. The methods and findings that will follow from the proposed research will make it possible to more accurately characterize and measure working memory deficits, which is an important component of ongoing efforts to develop treatments for cognitive impairments in schizophrenia.
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