Intrinsic functional connectivity networks in endogenously maintained cognitive states

The brain is arguably the single most complex system that exists within our universe. Its dynamic activations are constant and unending, and it is never truly at rest, even when we are asleep. These spontaneous fluctuations are not unorganized, with sets of anatomically distinct but functionally connected brain regions forming intrinsic connectivity networks (ICNs). These ICNs are consistently extracted from mere minutes of neuroimaging scans and are highly stable within each individual person. Regions within these ICNs and across these ICNs do not operate in isolation, with their patterns of activations and interactions under continuous change. These changes occur both to meet changing cognitive demands, as well as spontaneously in the absence of any external influence, and in several instances have demonstrated behavioral relevance. The full extent of the functional significance of these ICN coactivations, however, remains poorly understood. In this dissertation, I explore the modulations in higher-order ICN (co)activity that occur endogenously, independent of any incoming sensory information. First, I explore these modulations in an experimentally manipulated manner. Chapter 2 looks at activation patterns during an explicit period of increased demand of preparatory endogenous control. Chapter 3 goes a step further and explores the network-to-network interactions during this preparatory period, first at the whole-network level and followed by a region-by-region analysis. I then focus on the spontaneously occurring modulations of ICN activation patterns and how they subsequently affect perception. Chapter 4 explores both the pre- and post-stimulus time periods of spontaneous (rather than experimentally manipulated) ICN fluctuations during a task designed to maximize behavioral variability while taxing endogenously maintained control. Finally, Chapter 5 summarizes the findings of previous chapters and suggests further avenues of research. With this work I hope to contribute to the understanding of distinct functional and behavioral relevance of ICNs and their interactions.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Psychology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Egan, Maximillian Kirichenko

Contributors dc:contributor

• Sadaghiani, Sepideh
• Gratton, Gabriele
• Beck, Diane
• Barbey, Aron
• Koyejo, Oluwasanmi

• Cognitive Control
• Intrinsic Functional Connectivity Networks
• Fmri
• Network Interactions

Statement dc:rights

• Copyright 2023 Maximillian Egan

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/122048

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F122048