Saturday, December 18, 2021

Research Roundup: "Default Mode & Frontal Executive Network Interactions Enable Interoceptive Attention & Mindfulness"

 Welcome back! Coming up, I'll be catching up on recently published research in the mindfulness, performance, and neuroscience arena. Here's a summary of this recent paper from Mishra et al. (2020) (full text)

What this study is about:

- Attention is a large part of cognitive control, and can be further subdivided into attention to external and internal sensations (exteroception and interoception.) The neural basis of exteroception is pretty well studied. Interoception, which can be trained through mindfulness practice, is a little more of a black box still. 

- This study looks mainly at the neural processes underlying distraction during interoceptive tasks (here, an attention to breathing task.)

What they did:

- N=161 subjects performed a finger-tap response after every two cycles of inhalation/exhalation

- The authors used the variability in this response as a marker of attention fluctuation. Greater consistency in finger tap responses = improved interoceptive attention control.

- They divided the results into "attentive trials" - where finger taps were most consistent, and "distracted trials" - where there was less consistency in finger tap responses. Brain activity and functional connectivity was analyzed during both types of trials.

Key questions: 

- Does consistency (on finger taps) relate to performance on cognitive tasks?

- What does the neural basis of consistent performance look like within individuals?

    - During attentive trials, there should be increased functional connectivity/brain activity in regions of the salience and cingulo-opercular networks.

    - During distracted trials, there should be increased dorsolateral prefrontal cortex (DLPFC) activation because of the increased cognitive effort required to suppress distractions.


- On distracted trials, increased DLPFC activity was seen (executive control region), and decreased precuneus activity was seen (a default mode network region.)

    - Increased DLPFC activity likely reflects greater effort needed to suppress distraction and reorient to the task.

    - Decreased precuneus activity may reflect the need for default mode network suppression during distractor suppression.

- Increased functional connectivity between DLPFC and precuneus was also noted during distracted trials, perhaps due to needing more cognitive control regions to suppress the default mode network when reorienting to task. 

- On attentive trials, there was increased functional connectivity between the anterior cingulate cortex (ACC) and insula.

    - These regions are involved in sustained attention, self regulation and emotion regulation - all of which are involved in interoceptive attention.

    - When subjects are on task (attentive), default mode network suppression is not required (as opposed to what was seen in the distracted trials.)

- Increased trait mindfulness in subjects correlates with increased functional connectivity between DLPFC and precuneus on distracted trials, and with increased functional connectivity between ACC and insula on attentive trials. 

    - Interpretation:  better mindfulness skills = stronger functional connectivity between the brain regions involved in distraction suppression and reorientation to tasks involved in interoceptive attention.

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