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In this article, Broadband Cortical Desynchronization Underlies the Human Psychedelic State, this sentene is said:

Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices.

I'll abbreviate posterior association cortices to PAC, and frontal association cortices to FAC.

As found out in this question, the above sentence really means that after psilocybin intake, the brain waves present in the PAC are high-level gamma frequencies, and the brain waves present in the FAC are delta and theta frequencies. They are the ones left, since the other bands were desynchronized away.

Now, since these are the bands left, does that mean that they are more prevalent? Does that mean that the PAC will be operating fully on high-level gamma frequencies and therefore there'll be more of these frequencies in the PAC than usually?

If so, does this mean that the senses of which the PAC is responsible for, will be heightened, since the gamma frequency is a higher frequency, meaning more information is passed in less time? And does that mean that the senses of which the FAC is responsible for, will be diminished, since the delta and theta frequencies are the lowest?

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    $\begingroup$ "They are the ones left, since the other bands were desynchronized away." - that's not actually what the paper from the last Q&A said. These are places and bands where there was a significant decrease in power. You do not know that the other bands are "left", just that they are not significantly decreased. It could be, for example, that power started low in those bands, and so there was nothing to decrease. It could be that power was high in bands that decreased, so now they are more similar. Also decrease in power is not necessarily the same thing as "desynchronization". $\endgroup$
    – Bryan Krause
    Feb 2, 2021 at 21:00
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    $\begingroup$ This paper is using that term. They should not, and you shouldn't carry it with you. $\endgroup$
    – Bryan Krause
    Feb 2, 2021 at 22:05
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    $\begingroup$ Desynchronization is a possible cause of power decreases in EEG because you can imagine each EEG recording as originating from the sum of many small nodes over some region of the brain near the contact. If those sources are in sync, they will sum. If they are not, some may cancel others out. However, you can also have power changes if individual nodes change amplitude. Separately, desynchronization is also used to refer to the whole broadband EEG, in which "synchronized" refers to brain states in which low frequency power is high (like slow wave sleep) and "desynchronized" is like wake. $\endgroup$
    – Bryan Krause
    Feb 2, 2021 at 22:12
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    $\begingroup$ The authors here may be trying to associate psychedelics with a "more awake than awake" brain state, and they're linking those two types of synchronization in doing so. There are some data that support this general idea, but I don't think that should apply to the data they present in this particular paper. $\endgroup$
    – Bryan Krause
    Feb 2, 2021 at 22:13
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    $\begingroup$ The meaning arose because when you are asleep, you have a "slow", synchronized EEG (synchronized in this context meaning lots of slow, low-frequency power). As a bit of an exaggeration, imagine a brain where every neuron oscillates together, from being inactive and hyperpolarized, to a second later being active and depolarized. Slow wave sleep is close to this state. There's very little information in this state, and little information processing if everything is just oscillating together slowly. Wake is very far from this state. $\endgroup$
    – Bryan Krause
    Feb 2, 2021 at 22:39

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