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@lyle_ren I think this is largely right, but it's unlikely that they are "closing" the brain (see nature.com/articles/s4158… among others). We might just consider that they "open" the brain to be more receptive to top-down influences, as I believe you are suggesting.

@pineurosci This seems counterintuitive since psychedelics are often described as “opening” the brain, but what’s actually happening is they’re gating what reaches the DMN while shifting the directional balance from bottom-up toward top-down control. Explains utility in PTSD and autism.

New work on the effects of psychedelics on hierarchical cortical propagations out in PNAS! pnas.org/doi/10.1073/pn… Counter to our expectations, psychedelics attenuated bottom-up propagations into the Default Mode Network across substances and species. Thread below:

@kfshinozuka @realJoshSiegel Thanks Kenneth!

@pineurosci @realJoshSiegel incredible work adam, congratulations on getting this published!

Many thanks to participants, collaborators, and funders! More info in our acknowledgments section.

That psychedelics reduce bottom-up activity propagations into the DMN directly informs how we may think about their impact on brain function. These results support recent theories highlighting how psychedelics can attenuate bottom-up processing rather than strengthening it.

PNAS Traveling-wave transcranial alternating current stimulation (twtACS) causally links neural timing to cognitive function This study developed a new brain stimulation method called traveling-wave transcranial alternating current stimulation (twtACS). Unlike conventional brain stimulation, twtACS creates electrical waves that move across the brain in a specific direction, similar to natural neural traveling waves. The researchers showed that these artificial traveling waves could: Change the timing of neural activity in the brain Control how signals propagate across brain regions Improve cognitive performance in humans depending on the direction of the wave They confirmed these effects using: Human intracranial recordings Monkey neural recordings Human behavioral experiments The study suggests that traveling waves are not just correlated with cognition but may causally influence cognitive function. This introduces a new way to noninvasively manipulate brain communication and potentially treat neurological disorders. pnas.org/doi/full/10.10…

How does TMS — a treatment for depression — reshape dysfunctional brain circuits? In our new Cell paper, we identify a cell type-specific prefrontal mechanism linking accelerated iTBS to antidepressant-like behavioral effects and circuit plasticity. cell.com/cell/fulltext/…

What are the neural correlates of human behavior? Much research has approached versions of this question between individuals but not within individuals. Are results from these 2 approaches similar? No! In over 4000 individuals, the neural correlates of cognitive control diverged between vs. within individuals -- a case of non-ergodicity and Simpson’s paradox. We think that non-ergodicity may be an important principle in human neuroscience. [1/12]

Diffusion MRI (dMRI) is a powerful tool to study white matter maturation. In our new preprint, we process and distribute a new resource of >24,000 ABCD dMRI scans using open source tools! We then evaluate how methods shape inferences about development. 🔗 bit.ly/3QMLG0K