Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Neuroscience

Supervisor

Mur, Marieke

2nd Supervisor

Khan, Ali R.

Co-Supervisor

Co-Supervisor

Abstract

Higher-order cognitive functions, such as working memory, attention, and decision making, depend strongly on the functional integrity of frontal and parietal cortices. However, the internal workings of the frontoparietal network (FPN) are not well understood. A major contributor to this knowledge gap is our limited understanding of the intrinsic functional organization of the FPN. In order to address this gap, we examine task-dependent reconfigurations of functional connectivity (FC) within the FPN. We analyzed fMRI task-state data from 924 individuals from the Human Connectome Project Young Adult study. Our results show that FC within the FPN is highly stable across time within individuals. Furthermore, FC within the FPN is more consistent within than between individuals and more consistent within than between tasks. Overall, our findings indicate that human individuals exhibit a partially unique fine-grained functional organization within the FPN, and that this organization contains a task-specific component.

Summary for Lay Audience

Our ability to plan ahead and flexibly adapt our behaviour to novel situations relies heavily on a network of frontal and parietal brain regions. These brain regions become active when we remember the recent past, make and execute plans, or become aware of mistakes. How do these brain regions support this diverse range of cognitive functions?

Research on human frontoparietal function has focused on identifying one-to-one mappings between brain regions and cognitive functions. This approach has not been as successful as originally anticipated. The majority of frontoparietal brain regions are not involved in just one but many cognitive functions, including working memory, decision making, and error detection. This suggests that a change in approach is necessary: instead of attempting to link activity of whole brain regions to specific cognitive functions, we should examine how local processing within the frontoparietal network supports behaviour during diverse cognitive tasks.

In order to understand local processing we need to understand the fine-grained functional organization of the frontoparietal network. In other words, we need to understand how information flows through the network during the execution of cognitive tasks. In this project, we aim to map the fine-grained functional organization of the frontoparietal network using functional magnetic resonance imaging (fMRI) data acquired in a large group of individuals. Our results indicate that the frontoparietal network indeed shows a fine-grained functional organization, and that this organization contains an individually unique component. Furthermore, the functional organization contains a task-general as well as a task-specific component.

Results will greatly enhance our understanding of the neural basis of human cognition and provide a starting point for exploring functional organization level targets to study causes of cognitive dysfunction.

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

Available for download on Saturday, December 31, 2022

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