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Title:Spatiotemporal Dynamics of Working Memory: Eros-Based Comparisons of Frontoparietal Network Activities in Preparation, Encoding, and Recognition Tasks
Author(s):Agran, Jason Eric
Doctoral Committee Chair(s):Gratton, Gabriele; Fabiani, Monica
Department / Program:Neuroscience
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Neuroscience
Abstract:The goals of this dissertation evolved from a central question, "Is the domain-general component of working memory subtended by a general-purpose brain circuit which is invariant across tasks or, alternatively, are different circuits or variations of this same circuit used for different tasks?" By using a neuroimaging approach, we translated this question into the following one, "Is there a subset of cortical activities whose spatial and temporal dynamics occur in a fixed pattern across different working memory paradigms and conditions? Alternatively, do different tasks which make use of domain-general working memory use either distinct sets of cortical structures, or a discrete temporal ordering of the same set of structures?" To make progress towards answering this question, and others that developed from it, we used the Event-Related Optical Signal (EROS), a neuroimaging methodology capable of providing both high spatial and temporal resolution, to investigate cortical working memory activities during three disparate, but commonly used working memory paradigms (task switching, selective encoding with gender categorization, and face-name recognition). Results of this study demonstrated that the frontoparietal network occupies a central role in domain-general working memory, and furthermore that the spatiotemporal dynamics of this network are indeed common across both similar and disparate working memory paradigms. Moreover, we found that the frontoparietal network is sensitive to the degree of conflict or interference in working memory tasks and demonstrates a number of operational modes; a high activation mode which is required for cognitive task rule switches and/or breaking and re-forming currently paired associations, and a low activation mode which is used for rule maintenance activities and low conflict recognition tasks. Additionally, we provided evidence that the predictive nature of frontoparietal network activities may extend across paradigms, and that the activities classically associated with subsequent memory effects might be better viewed from a network perspective, rather than those of its functional components. Finally, we observed that this domain-general network operates in a fixed frontal-then-parietal sequence whether subjects made selections among competing alternatives, switched between task sets, selectively encoded face-name information, or recognized paired associations.
Issue Date:2007
Description:160 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.
Other Identifier(s):(MiAaPQ)AAI3269827
Date Available in IDEALS:2015-09-25
Date Deposited:2007

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