[VIDEO] Mind-wandering, meta-cognition, and the function of consciousness

Hey everyone! I recently did an interview for Neuro.TV covering some of my past and current research on mind-wandering, meta-cognition, and conscious awareness. The discussion is very long and covers quite a diversity of topics, so I thought i’d give a little overview here with links to specific times.

For the first 15 minutes, we focus on general research in meta-cognition, and topics like the functional and evolutionary signifigance of metacognition:

We then begin to move onto specific discussion about mind-wandering, around 16:00:

I like our discussion as we quickly get beyond the overly simplistic idea of ‘mind-wandering’ as just attentional failure, reviewing the many ways in which it can drive or support meta-cognitive awareness. We also of course briefly discuss the ‘default mode network’ and the (misleading) idea that there are ‘task positive’ and ‘task negative’ networks in the brain, around 19:00:

Lots of interesting discussion there, in which I try to roughly synthesize some of the overlap and ambiguity between mind-wandering, meta-cognition, and their neural correlates.

Around 36:00 we start discussing my experiment on mind-wandering variability and error awareness:

A great experience in all, and hopefully an interesting video for some! Be sure to support the kickstarter for the next season of Neuro.TV!

JF also has a detailed annotation on the brainfacts blog for the episode:

“0:07″ Introduction
“0:50″ What is cognition?
“4:45″ Metacognition and its relation to confidence.
“10:49″ What is the difference between cognition and metacognition?
“14:07″ Confidence in our memories; does it qualify as metacognition?
“18:34″ Technical challenges in studying mind-wandering scientifically and related brain areas.
“25:00″ Overlap between the brain regions involved in social interactions and those known as the default-mode network.
“29:17″ Why does cognition evolve?
“35:51″ Task-unrelated thoughts and errors in performance.
“50:53″ Tricks to focus on tasks while allowing some amount of mind-wandering.

Switching between executive and default mode networks in posttraumatic stress disorder [excerpts and notes]

From: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895156/?tool=pubmed

Daniels et al, 2010

We decided to use global scaling because we were not analyzing anticorrelations in this paradigm and because data presented by Fox and colleagues66 and Weissenbacher and coworkers65 indicate that global scaling enhances the detection of system-specific correlations and doubles connection specificity. Weissenbacher and colleagues65 compared different preprocessing approaches in human and simulated data sets and recommend applying global scaling to maximize the specificity of positive resting-state correlations. We used high-pass filtering with a cut-off at 128 seconds to minimize the impact of serial autocorrelations in the fMRI time series that can result from scanner drift.

Very useful methodological clipping!

The control condition was a simple fixation task, requiring attention either to the response instruction or to a line of 5 asterisks in the centre of the screen. We chose this control task to resemble the activation task as closely as possible; it therefore differed considerably from previous resting state analyses because it was relatively short in duration and thus necessitated fast switches between the control condition and the activation task. It also prompted the participants to keep their eyes open and fixated on the stimulus, which has been shown to result in stronger default mode network activations than the closed-eyes condition.60

Good to remember: closed-eyed resting states result in weaker default mode activity.

To ensure frequent switching between an idling state and task-induced activation, we used a block design, presenting the activation task (8 volumes) twice interspersed with the fixation task (4 volumes) within each of 16 imaging runs. Each task was preceded by an instruction block (4 volumes duration), amounting to a total acquisition of 512 volumes per participant. The order of the working memory tasks was counterbalanced between runs and across participants. Full details of this working memory paradigm are provided in the study by Moores and colleagues.6 There were 2 variations of this task in each run concerning the elicited button press response; however, because we were interested in the effects of cognitive effort on default network connectivity, rather than specific effects associated with a particular variation of the task, we combined the response variations to model a single “task” condition for this study. The control condition consisted of periods of viewing either 5 asterisks in the centre of the screen or a notice of which variation of the task would be performed next.

Psychophysiological interaction analyses are designed to measure context-sensitive changes in effective connectivity between one or more brain regions67 by comparing connectivity in one context (in the current study, a working memory updating task) with connectivity during another context (in this case, a fixation condition). We used seed regions in the mPFC and PCC because both these nodes of the default mode network act independently across different cognitive tasks, might subserve different subsystems within the default mode network and have both been associated with alterations in PTSD.8

This paradigm is very interesting. The authors have basically administered a battery of working memory tasks with interspersed rest periods, and carried out ROI inter-correlation, or seed analysis. Using this simple approach, a wide variety of experimenters could investigate task-rest interactions using their existing data sets.

Limitations

The limitations of our results predominantly relate to the PTSD sample studied. To investigate the long-lasting symptoms that accompany a significant reduction of the general level of functioning, we studied alterations in severe, chronic PTSD, which did not allow us to exclude patients taking medications. In addition, the small sample size might have limited the power of our analyses. To avoid multiple testing in a small sample, we only used 2 seed regions for our analyses. Future studies should add a resting state scan without any visual input to allow for comparison of default mode network connectivity during the short control condition and a longer resting state.

The different patterns of connectivity imply significant group differences with task-induced switches (i.e., engaging and disengaging the default mode network and the central-executive network).