Two Default Modes, Internal and External, Revealed through Whole-brain Synchrony
Poster No:
2483
Submission Type:
Abstract Submission
Authors:
Isaac Christian1, Samuel Nastase2, Michael Graziano2
Institutions:
1Princeton, Princeton, NJ, 2Princeton University, Princeton, NJ
First Author:
Co-Author(s):
Introduction:
The 'default mode' of cognition usually refers to an automatic propensity to simulate past, future, and hypothetical experiences, rather than attending to external events in the moment (Verschooren and Egner 2023). 'Mind wandering' usually refers to moments when people's attention drifts from external tasks to become engaged in internal, default-mode cognition. However, we suggest a more general formulation in which attention to external events can also become a default mode, when those events are information rich or salient. Likewise, mind wandering is not just movement of attention from an external task to internal cognition, but can also involve movement of attention from an internal task to external distractors. In this study, we used a focused attention task and whole brain synchrony to study involuntary shifts of attention bi-directionally, between external and internal states.
Methods:
Forty participants completed an internal and external focused attention task in an MRI machine. In the external condition, participants were instructed to pay attention to a ∼2 minute video clip and press a button if they noticed their mind had wandered from the video content. In the internal condition, participants viewed another video clip, this time tasked with ignoring the video and instead focusing on the rhythmic sensation of their breathing, while pressing a button if they noticed that their mind had wandered off their breathing. Each video was presented four times in succession. Thus, the video stimulus was more likely to attract attention on the first presentation, and less so by the fourth presentation. In addition, some videos were selected to be intrinsically interesting (high salience) and others to be uninteresting (low salience). Participants viewed a total of 6 videos, three high and three low salience. Self-reported mind wandering events (button presses) were used as an indirect measure of attention (more presses = less attention on task), and inter-subject correlation (ISC) was used to measure whole-brain attention synchrony to the video stimulus.
Results:
When subjects tried to focus attention on the videos (the external focus condition), more mind wandering events occurred as the videos became less interesting (i.e. after more repetitions) and when less interesting videos were presented, suggesting a default mode of internal attention. When subjects focused on their breathing, more mind wandering events occurred when videos were most interesting (i.e. on the first repetition) and when more interesting videos were presented. In this case, subjects were biased toward an external default mode of attention, causing their minds to more frequently wander from the internal task. These behavioral results were reflected in brain activity. ISC analyses, which probe a neural signature of external attention, found that attention to the video was greater in the external focus condition than the internal focus condition; was greater to high salience videos than to low salience videos; and decreased as each video was repeated.
Conclusions:
Our results illustrate that there are two default modes. When the external world is interesting, the default mode is to encode the external information. In contrast, when external information is not useful or exciting, the brain automatically decouples from the external environment and engages with internal simulation in a default manner. Automatic mind wandering from a desired task can therefore occur in either direction, depending on circumstances. This automatic orienting transcends an endogenous (voluntary and internally driven) and exogenous (involuntary and externally driven) distinction, showing that attention can be involuntarily drawn by an internal event just as it can by an external stimulus. Arbitrary top-down goals, such as focusing on the breath, or focusing on a video, can sometimes align with, and sometimes conflict with, the 'default' bias of orienting attention internally or externally.
Higher Cognitive Functions:
Executive Function, Cognitive Control and Decision Making 2
Higher Cognitive Functions Other
Perception, Attention and Motor Behavior:
Consciousness and Awareness
Perception and Attention Other 1
Keywords:
FUNCTIONAL MRI
Meta-Cognition
1|2Indicates the priority used for review