Psilocybin 🍄

Question 1

Scale for measuring the acute psychological effects of psilocybin:

Answer 1

5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)

Question 2

The dimensions (5) of 5D-ASC:

Answer 2

(1) Oceanic Boundlessness
(2) Anxious Ego Dissolution
(3) Visionary Restructuralization
(4) Auditory Alterations
(5) Reduction of Vigilance

Question 3

What is the active metabolite of psilocybin?

Answer 3

Psilocin

Question 4

What receptor does psilocin act upon? Is it an agonist, antagonist?

Answer 4

5-HT2A agonist

Question 5

What is the behavioural equivalent of psychedelic effects in rodents?

Answer 5

The head twitch response

Question 6

What type of a receptor is 5-HT2A?

Answer 6

G protein-coupled receptor (GPCR)

Question 7

GPCR signalling cascade:

Answer 7

1. Psilocin binds to 5-HT2A
2. G-protein is activated and activates PLC
3. PLC cleaves PIP2 into IP3 and DAG
4. IP3 and DAG co-activate protein kinase C (PKC)
5. PKC activates arachidonic acid

Question 8

What happens behaviourally and biologically after repeated psilocybin administration?

Answer 8

• Rapid tolerance
• Downregulation of 5-HT2A receptors

Question 9

Can you become addicted to psilocybin? Why?

Answer 9

No!
No significant (or even inhibitory) effect on the dopaminergic system

Question 10

What regions are a part of the default mode network (DMN)?

Answer 10

1. The medial prefrontal cortex
2. The posterior cingulate cortex
3. Precuneus
4. The angular gyrus

Question 11

Key characteristics of DMN:

Answer 11

1. Receives more blood flow and consumes more energy than other brain regions
2. Centre of high connectivity
3. Engaged in higher-level metacognition

Question 12

What happens to between-network activity on psilocybin?

Answer 12

It increases, resulting in a less constrained, more flexible, less self-referential and egoic mind

Question 13

Main idea of the REBUS Model in terms of psychedelics:

Answer 13

Psychedelics may lead to positive therapeutic outcomes through modulating previous maladaptive beliefs by allowing the brain to create a greater array of functional connectivity (FC) patterns and networks

Question 14

Psilocybin as treatment for depression:

Answer 14

1. Increases global network integration
2. Decreases DMN connectivity
3. Increases integration between the executive and salience networks

Question 15

(molecular level) Mechanism through which psilocybin modulates neuroplasticity:

Answer 15

5-HT2A R activation —> ↑ glutamate —> AMPA R activation —> ↑ BDNF secretion —> TrkB receptors and mTOR

Question 16

How does psilocybin modulate neuroplasticity?

Answer 16

1. Neuroplasticity-related gene (Arc, c-Fos) upregulation
2. Synaptic strengthening (LTP)
3. Increase of pre- and post-synaptic density
4. Enhanced dendritic growth
5. Adult neurogenesis