Default Mode Network reduced during meditation and psychedelics - vid clip
What you see is only the activation of the thalamus... a sensory gate which is a kind of open presence...you're not seeing differential high activity in the prefrontal cortex....If you go by the standard reductionist material perspective, if a person is in a HIGHER state of consciousness then MORE prefrontal cortex should be activated: What we are seeing is actually the reverse...so HOW do you explain that...?
Science lecture on mystical experiences of psilocybin - vid
at 50 minutes in - this Neuroscientist lady (one of the below scientist authors) makes this crucial point about the paradox what is "higher" or formless awareness consciousness -with a HOW question
A recent meta-analysis found that DMN activity was consistently reduced during meditation compared to control conditions across neuroimaging studies of meditation involving either focused attention or the repetition of phrases (Tomasino, Fregona, Skrap, & Fabbro, 2012). The same study by our research group found that DMN activity was reduced in meditators compared to controls across three standard mindfulness meditations: focused concentration, loving kindness, and choiceless awareness (Brewer, Worhunsky, et al., 2011). Determining that there are neural mechanisms common across meditation practices may inform the generalizability and potential clinical applications of these techniques.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4529365/
Meditation leads to reduced default mode network activity beyond an active task
Although the meta-analysis did not find a difference in DMN activity associated with long-term experience, our prior study found reduced activity in regions of the DMN during meditation relative to rest in experienced meditators compared to non-meditators (Brewer, Worhunsky, et al., 2011). This study replicated that previous study in a larger sample (meditators: 20 versus 12; controls: 26 versus 12).
Brewer JA, Worhunsky PD, Gray JR, Tang YY, Weber J, Kober H. Meditation experience is associated with differences in default mode network activity and connectivity. Proceedings of the National Academy of Sciences. 2011;108(50):20254–20259. doi: 10.1073/pnas.1112029108.
However, functional connectivity in regions of the DMN, a measure of the temporal correlation of BOLD signal between these regions, has also been found to differ between meditators and controls, not only during meditation but also at rest (Brewer, Worhunsky, et al., 2011; Pagnoni, 2012; Taylor et al., 2013). This suggests that meditation training may alter the behavioral state individuals enter in to when given the standard resting state instructions. Meditators and controls appear to differ in their resting state DMN processing.
Other studies have reported a high incidence of mind wandering in healthy individuals (Killingsworth & Gilbert, 2010; Whitfield-Gabrieli et al., 2011), and a high incidence of precuneus/posterior cingulate cortex activity associated with mind wandering (Pagnoni, 2012). In contrast, meditators showed increased activity in the precuneus during the judgment of adjectives task (Figure 2), possibly reflecting increased self-related processing relative to the implicit baseline. This interpretation would be consistent with our prior finding that meditators showed altered DMN functional connectivity at rest as compared to non-meditators (Brewer, Worhunsky, et al., 2011). Related to this, we have used real-time fMRI neurofeedback, in which individuals are provided dynamic visual feedback about their ongoing brain activity in real-time, to demonstrate that changes in activity in the posterior cingulate cortex correspond to experienced meditator’s subjective reports of focused attention and mind wandering (Garrison, Santoyo, et al., 2013; Garrison, Scheinost, et al., 2013). The current findings suggest further that long-term meditation experience may lead to changes in DMN activity beyond typical task engagement-related reductions because meditators showed reduced DMN activity during meditation not only compared to rest, but also compared to another active cognitive task. For meditators, this is consistent with the hypothesis that meditation may reduce self-related thinking and mind wandering more than another active task.
Mind wandering and self-related processing contribute to ruminative thinking which may be a feature of these disorders and has also been associated with decreased well-being (e.g., Killingsworth & Gilbert, 2010). In contrast, meditation, which appears to be associated with reduced activity in the DMN, has been shown to improve attention and working memory performance (Pagnoni, 2012) and promote positive health outcomes (Keng, Smoski, & Robins, 2011). As mindfulness training has shown utility for addiction (Brewer, Mallik, et al., 2011), as well as for pain, anxiety and depression (Goyal et al., 2014), these studies together suggest that a neural mechanism by which meditation results in clinical benefits may be through reducing DMN activity.
Many philosophical and contemplative traditions teach that “living in the moment” increases happiness. However, the default mode of humans appears to be that of mind-wandering, which correlates with unhappiness, and with activation in a network of brain areas associated with self-referential processing. We investigated brain activity in experienced meditators and matched meditation-naive controls as they performed several different meditations (Concentration, Loving-Kindness, Choiceless Awareness). We found that the main nodes of the default-mode network (medial prefrontal and posterior cingulate cortices) were relatively deactivated in experienced meditators across all meditation types. Furthermore, functional connectivity analysis revealed stronger coupling in experienced meditators between the posterior cingulate, dorsal anterior cingulate, and dorsolateral prefrontal cortices (regions previously implicated in self-monitoring and cognitive control), both at baseline and during meditation. Our findings demonstrate differences in the default-mode network that are consistent with decreased mind-wandering. As such, these provide a unique understanding of possible neural mechanisms of meditation.
https://pubmed.ncbi.nlm.nih.gov/26921712/
Both groups reported that decreased PCC activity corresponded with effortless awareness
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