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=Volume 5 - 2017

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, 8F/12M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the steady-state execution of a sustained working memory n-back task.
We found that the steady state execution of such a task 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 steady-state task execution, can contribute to a better understanding of how brain networks rearrange themselves in response of a task.