Psychedelic neuroimaging

TABLE year, drug, type, method, summary
FROM [[Psychedelic neuroimaging]]
WHERE contains(tags,"reference/literature")
SORT year

Tldr

from Shinozuka2023

Subtopics

Psychedelics and BOLD activation
Psychedelics in resting-state networks

Entropy analyses

Psychedelic studies on criticality
Psychedelic studies using sample entropy
Psychedelic studies using Shannon entropy
Psychedelic studies using Lempel-Ziv complexity

Viol2019 → characterizing complex networks using entropy-degree diagrams
Viol2017 → Shannon entropy of brain functional complex networks under ayahuasca
Li2019 → cortical dynamics during ketamine

fMRI research has so far failed to differentiate the action of psychedelics with respect to specific region or network-wise changes Girn2023

• Minimal overlap across drugs & datasets wrt network interactions
  • Daws2022
  • Muller2018
    • No single consistent change in between-network FC across three data sets
  • Muller2018
  • Roseman2014
  • Mason2020
    • Poor consistency against the three datasets (Muller2018, Roseman2014, Carhart-Harris2016a)
  • Madsen2021
• Discrepancies in global integration of distinct region
  • Preller2020
  • Preller2018
  • Tagliazucchi2016
  • Girn2022
• Network-specific effects (e.g. DMN) have been found with pharmacologically distinct drug
  • Muller2021
  • Doss2020
  • Klaassens2015

Imperial College London datasets and UZH had diametrically opposed effects → ICL datasets significantly increase global FC in transmodal association regions incl. DMN and frontopartetal, UZH minimal changes to transmodal regions & instead increased global FC in somatomotor & visual Girn2023 (I wouldn’t call that diametrically opposed?)

• failure of global FC to find consistent changes Girn2023

Several investigations have found increased FC between the thalamus and sensorimotor regions following psychedelic administration Girn2023 → Muller2018, Preller2018, Tagliazucchi2016, Klaassens2015

• Not specific to psychedelics, found across each of LSD, amphetamine, MDMA Avram2022
• May be an artifact of averaging over heterogenous thalamic subdivisions Gaddis2022

Lord2019 → network-independent, globally coherent phase-locking pattern substate increased in probability of occurrence (reanalysis of psilocybin data from Carhart-Harris2012)

first psychedelic fMRI studies examined glucose metabolism Gouzoulis-Mayfrank1999 Vollenweider1997a and blood flow Hermle1992 Riba2006

recent studies examined task-related effects Barrett2018 Carhart-Harris2012 Daumann2010 Kraehenmann2015 Mueller2017 Preller2016 Preller2017 Schmidt2018 Spitzer2001 or after psychedelic session Barrett2020

• Decreased within-network FC (“integration”)
  • Carhart-Harris2016
  • Carhart-Harris2012
• increased between-network FC (“segregation”) is the most common finding (latter is confirmed by Shinozuka2023)
  • Carhart-Harris2016
  • Roseman2014
• Larger repertoire of brain connectivity profiles
  • Tagiazucchi2014
  • Lord2019
  • Atasoy2017
• Global hyperconnected brain state
  • Tagliazucchi2016
• Freer transitions between brain states
  • Singleton2022
  • Atasoy2017
• Reduction of principal sensory-association cortex gradient
  • Girn2022
• Above studies converge on the action of psychedelics on the transmodal cortex
• Subjective effects of psychedelics rely on dysregulation of association cortices
• Cortical dysregulation disinhibits lower, developmentally/evolutionarily earlier systems (e.g. limbic system)

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References

McCulloch2022
Aday2020
Girn2023