Shifting across internally and externally oriented cognition: behavioural and neural explorations using task-switching and resting-state paradigms

Calzolari, Sara ORCID: 0000-0003-3693-9071 (2024). Shifting across internally and externally oriented cognition: behavioural and neural explorations using task-switching and resting-state paradigms. University of Birmingham. Ph.D.

Preview

Calzolari2023PhD.pdf
Text
Available under License All rights reserved.
Download (9MB) | Preview

Abstract

The human brain frequently shifts between internal and external monitoring, and these changes in cognitive content can occur spontaneously or intentionally both at rest as well as during task performance. Specific frontoparietal networks have been associated with internal and external cognition and were shown to often display anticorrelated activation. Despite this being a persistent feature of human cognition, the neuroscientific study of cognitive flexibility lacks proper investigation of the exchange between internal and external processes. Cognitive flexibility research commonly employs task-switching paradigms, which often demonstrated the presence of switch costs (decreased performance) and increased lateral frontoparietal activation in conditions where people switched between tasks as compared to repeating the same task. However, all these studies mainly focused on switching between tasks requiring attention to external stimulus features, and have not investigated switching across internal and external cognition. Specifically, no studies have ever explored task-switching involving self-referential processes. Therefore, it is of interest to the scientific community to expand our understanding of cognitive flexibility in relation to these prominent aspects of cognition. In addition to this, despite the great deal of attention towards the correlation patterns between frontoparietal networks, there is little neuroscientific research focusing on identifying specific points of change within and across these networks. Therefore, this thesis investigates the behavioural and neural correlates of cognitive shifts across self-referential and externally oriented processes using novel task-switching paradigms, and explores the changes in brain networks subserving internal and external cognition at rest using change-point detection. Chapter 3 finds significant behavioural switch costs both in the external and internal domain, as well as additional costs in switching between domains as compared to within each domain. Chapter 4 partly replicates these behavioural findings and finds domain-specific activation of dorsal attention and default mode network when preparing externally and internally oriented tasks, respectively, as well as domain-general preparatory control in lateral parietal regions and dorsal precuneus. Chapter 5 investigates the same task-switching dynamics with another paradigm using different tasks and stimuli, confirming the presence of switch costs in both domains, but not the presence of additional costs to between-domain switching. Finally, Chapter 6 investigates the brain activity around change points as found through change-point detection and reveals small clusters in mediodorsal thalamus and regions of salience and default mode networks. It also explores dynamic functional connectivity and graph measures after segmentation based on this novel approach. Moreover, it examines the differences in the above measures across chronotypes, probing the effects of arousal fluctuations on brain dynamics, as induced by circadian preferences. Together, these empirical chapters provide novel information regarding the cognitive control of domain switching when involving internally oriented versus externally oriented tasks, and regarding the resting-state dynamics of the networks underlying these processes. Due to COVID-19, the entire trajectory of the thesis was adapted to allow the conduction of online behavioural studies (Chapters 3 and 5) and the analysis of existing datasets (Chapter 6), while waiting for in-person testing to resume (Chapter 4).

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):