AUTHOR=Tommasin Silvia , Mascali Daniele , Gili Tommaso , Eid Assan Ibrahim , Moraschi Marta , Fratini Michela , Wise Richard G. , Macaluso Emiliano , Mangia Silvia , Giove Federico TITLE=Task-Related Modulations of BOLD Low-Frequency Fluctuations within the Default Mode Network JOURNAL=Frontiers in Physics VOLUME=5 YEAR=2017 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2017.00031 DOI=10.3389/fphy.2017.00031 ISSN=2296-424X ABSTRACT=

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33 ± 6 years, 8 F/12 M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the continuous execution of a working memory n-back task. We found that task execution impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to continuous task execution, can contribute to a better understanding of how brain networks rearrange themselves in response to a task.