Default mode and visual network activity in an attention task: Direct measurement with intracranial EEG

Abstract

Dynamic attention states are necessary to navigate the ever changing task demands of daily life. Previous investigations commonly utilize a block paradigm to study sustained and transient changes in attention networks. fMRI investigations have shown that sustained attention in visual block design attention tasks corresponds to decreased signal in the default mode and visual processing networks. While task negative networks are anticipated to decrease during active task engagement, it is unexpected that visual networks would also be suppressed during a visual task where event-related fMRI studies have found transient increases to visual stimuli. To resolve these competing results, the current investigations utilized intracranial EEG to directly interrogate visual and default mode network dynamics during a visual continuous performance task. We used the electrophysiological data to model expected fMRI signals and to maximize interpretation of current results with previous investigations. Results show broadband gamma power decreases in the default mode network, corresponding to previous EEG and fMRI findings. Meanwhile, visual processing regions including the primary visual cortex and fusiform gyrus demonstrate both sustained decreases during task engagement and stimuli-driven transient increases in gamma power. Modeled fMRI based on gamma power reproduces signal decreases reported in the fMRI literature, and emphasizes the insensitivity of fMRI to transient, regularly spaced signal changes embedded within sustained network dynamics. The signal processing functions of the dynamic visual and default mode network changes explored in this study are unknown but may be elucidated through further investigation.

Brain networks in human conscious visual perception

“…A dynamic transient pulse in subcortical arousal (e.g., MT and Th) and emotional/motivational systems (e.g., NA) facilitates bottom-up attentional salience and top-down attentional control (23,29,30). Next, (2) Default-mode network (DMN): switching off the DMN and related circuits can reduce competing signals to prevent interference with conscious perception (9,(31)(32)(33). Finally, (3) Task-positive networks (TPN): a broad wave of hierarchical processing sweeps through task-positive cortical and subcortical areas to fully process the event before it is encoded in working and episodic memory systems.…”

The major brain networks of human visual consciousness

“…A dynamic transient pulse in subcortical arousal (e.g., MT and Th) and emotional/motivational systems (e.g., NA) amplifies and facilitates bottom-up attentional salience and top-down attentional control 25,31,32 . Next, (2) Default-mode network (DMN): switching off of the DMN and related circuits can reduce competing signals to prevent interference with conscious perception 9,[33][34][35] . Finally, (3) Taskpositive networks (TPN): a broad wave of hierarchical processing sweeps through task-positive cortical and subcortical areas to fully process the event before it is encoded in working and episodic memory systems.…”

Co‐activation pattern alterations in autism spectrum disorder–A volume‐wise hierarchical clustering fMRI study

“…Faster imaging and dynamic lag analysis (Kotila et al, 2020;Raatikainen et al, 2020) or causality analysis methods (Bernas et al, 2018;Bielczyk et al, 2019;Borchers et al, 2012;Chen et al, 2016;Deshpande & Hu, 2012;Kaminski et al, 2016;Li et al, 2020) may shed light on interactions between attention, visual, and other brain networks. MREG fMRI coupled with simultaneous EEG analysis (Hiltunen et al, 2014;Li et al, 2019;Ridley et al, 2017) could clarify the relationship between the neural avalanches and the brain's electrical activity in the future.…”