Author: Saurabh Bhaskar Shaw1, Margaret C McKinnon2, Jennifer Heisz3, Suzanna Becker4
Affiliation: <sup>1</sup> Neuroscience Graduate Program, McMaster University, Hamilton, ON, Canada; Vector Institute for Artificial Intelligence, Toronto, ON, Canada; Centre for Advanced Research in Experimental and Applied Linguistics (ARiEAL), Department of Linguistics and Languages, McMaster University, Hamilton, ON, Canada.
<sup>2</sup> Department of Psychiatry and Behavioural Neuroscience, McMaster University, Hamilton, ON, Canada; Mood Disorders Program, St. Joseph's Healthcare, Hamilton, ON, Canada; Homewood Research Institute, Guelph, ON, Canada; Rotman Research Institute, Baycrest Hospital, Toronto, ON, Canada.
<sup>3</sup> Department of Kinesiology, McMaster University, Hamilton, ON, Canada; Rotman Research Institute, Baycrest Hospital, Toronto, ON, Canada.
<sup>4</sup> Neuroscience Graduate Program, McMaster University, Hamilton, ON, Canada; Department of Psychology Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada; Vector Institute for Artificial Intelligence, Toronto, ON, Canada; Centre for Advanced Research in Experimental and Applied Linguistics (ARiEAL), Department of Linguistics and Languages, McMaster University, Hamilton, ON, Canada; Rotman Research Institute, Baycrest Hospital, Toronto, ON, Canada. Electronic address: becker@mcmaster.ca.
Conference/Journal: Brain Cogn
Date published: 2021 Jul 1
Other:
Volume ID: 151 , Pages: 105725 , Special Notes: doi: 10.1016/j.bandc.2021.105725. , Word Count: 402
The highly influential tri-network model proposed by Menon integrates 3 key intrinsic brain networks - the central executive network (CEN), the salience network (SN), and the default mode network (DMN), into a single cohesive model underlying normal behaviour and cognition. A large body of evidence suggests that abnormal intra- and inter- network connectivity between these three networks underlies the various behavioural and cognitive dysfunctions observed in patients with neuropsychiatric conditions such as PTSD and depression. An important prediction of the tri-network model is that the DMN and CEN networks are anti-correlated under the control of the SN, such that if a task engages one of the two, the SN inhibits the activation of the other. To date most of the evidence surrounding the functions of these three core networks comes from either resting state analyses or in the context of a single task with respect to rest. Few studies have investigated multiple tasks simultaneously or characterized the dynamics of task switching. Hence, a careful investigation of the temporal dynamics of network activity during task switching is warranted. To accomplish this we collected fMRI data from 14 participants that dynamically switched between a 2-back working memory task and an autobiographical memory retrieval task, designed to activate the CEN, DMN and the SN. The fMRI data were used to 1. identify nodes and sub-networks within the three major networks involved in task-linked dynamic network switching, 2. characterize the temporal pattern of activation of these nodes and sub-networks, and finally 3. investigate the causal influence that these nodes and sub-networks exerted on each other. Using a combination of multivariate neuroimaging analyses, timecourse analyses and multivariate Granger causality measures to study the tri-network dynamics, the current study found that the SN co-activates with the task-relevant network, providing a mechanistic insight into SN-mediated network selection in the context of explicit tasks. Our findings also indicate active involvement of the posterior insula and some medial temporal nodes in task-linked functions of the SN and DMN, warranting their inclusion as network nodes in future studies of the tri-network model. These results add to the growing body of evidence showing the complex interplay of CEN, DMN and SN nodes and sub-networks required for adequate task-switching, characterizing a normative pattern of task-linked network dynamics within the context of Menon's tri-network model.
Keywords: Central executive network; Connectome-multivariate pattern analyses (connectome-MVPA); Default mode network; Graph theory; Multivariate Granger Causality (MVGC); Salience network; Tri-network model.
PMID: 33932747 DOI: 10.1016/j.bandc.2021.105725