Background connectivity between frontal and sensory cortex depends on task state, independent of stimulus modality

Abstract

The human brain has the ability to process identical information differently depending on the task. In order to perform a given task, the brain must select and react to the appropriate stimuli while ignoring other irrelevant stimuli. The dynamic nature of environmental stimuli and behavioral intentions requires an equally dynamic set of responses within the brain. Collectively, these responses act to set up and maintain states needed to perform a given task. However, the mechanisms that allow for setting up and maintaining a task state are not fully understood. Prior evidence suggests that one possible mechanism for maintaining a task state may be through altering 'background connectivity,' connectivity that exists independently of the trials of a task. Although previous studies have suggested that background connectivity contributes to a task state, these studies have typically not controlled for stimulus characteristics, or have focused primarily on relationships among areas involved with visual sensory processing. In the present study we examined background connectivity during tasks involving both visual and auditory stimuli. We examined the connectivity profiles of both visual and auditory sensory cortex that allow for selection of task-relevant stimuli, demonstrating the existence of a potentially universal pattern of background connectivity underlying attention to a stimulus. Participants were presented with simultaneous auditory and visual stimuli and were instructed to respond to only one, while ignoring the other. Using functional MRI, we observed task-based modulation of the background connectivity profile for both the auditory and visual cortex to certain brain regions. There was an increase in background connectivity between the task-relevant sensory cortex and control areas in the frontal cortex. This increase in synchrony when receiving the task-relevant stimulus as compared to the task irrelevant stimulus may be maintaining paths for passing information within the cortex. These task-based modulations of connectivity occur independently of stimuli and could be one way the brain sets up and maintains a task state.

Context-specific abnormalities of the central executive network in first-episode psychosis: relationship with cognition

“…An important piece of our results is that we observe less engagement of this state-dependent network during WM beyond the intrinsic signal, representing an impaired ability to achieve this context-specific brain state in FEP participants. To date, much of the work with ‘background’ states is limited to sensory systems (Al-Aidroos et al, 2012; Elkhetali et al, 2019; Norman-Haignere et al, 2012; Tompary, Al-Aidroos, & Turk-Browne, 2018), and their relationship to higher-order regions (Griffis, Elkhetali, Burge, Chen, & Visscher, 2015). More recent evidence has focused on reward processing by showing that ‘background’ motivational contexts relate to mesolimbic connectivity and task-performance across adolescent development (Murty et al, 2018).…”

“…a WM cue) to better characterize state-dependent shifts that extend across the entire task (i.e. an entire run of a WM task) (Al-Aidroos, Said, & Turk-Browne, 2012; Elkhetali et al, 2019; Murty et al, 2018; Norman-Haignere, McCarthy, Chun, & Turk-Browne, 2012). While most analyses of task-based neuroimaging data focus on responses to specific trials on the magnitude of seconds, background connectivity allows for the assessment of executive states unfolding over the course of seconds to minutes.…”

The fMRI correlates of visuo-spatial abilities: sex differences and gender dysphoria

“…From such a residual sequence, containing the BOLD signal after that task related effects were regressed out, the average time course of the selected ROI was extracted and used to calculate the linear correlation with every voxel within the brain mask. Correlation values contained in the resulting volumes represent the background connectivity associated to the experimental task (Elkhetali et al, 2019 ).…”

Midazolam and Ketamine Produce Distinct Neural Changes in Memory, Pain, and Fear Networks during Pain

“…This allows background connectivity to be assessed with minimal contamination from task events. 23,24 Group-level connectivity contrasts for saline greater than midazolam and saline greater than ketamine were calculated and thresholded within Conn Toolbox, correcting the overall significance for a cluster false-discovery rate of P < 0.05. 25 Complete lists of all clusters showing statistically significant connectivity change with drug are available (see tables, Supplemental Digital Content 1 [http://links.lww.com/ALN/C585] for saline greater than midazolam, and Supplemental Digital Content 2 [http://links.lww.com/ALN/C586] for saline greater than ketamine).…”