L4 - Altered States of Consciousness

Question 1

What are the basic effects of hallucinogens?

Answer 1

• usually cause perceptual distortions (eg. Illusions of motion), rarely cause full hallucinations
• ego dissolution - altered sense of self (blurred boundary of where self and other things are)
• negative side effects are mostly from the drug EXPERIENCE (eg. risk taking). the drugs themselves aren’t toxic or addictive.

Question 2

What was LSD experimentally to treat?

Answer 2

Scz

but found that it increased rather than decreased symptoms

Question 3

What is psilocybin currently used for?

Answer 3

• tested as treatment for OCD, anorexia & bulimia, cluster headaches and addiction.
• therapy to reduce death anxiety in terminal cancer
• Used to model psychosis - inducing psychosis-like episodes in healthy people to understand clinical psychosis and find new drug targets
• Used to understand role of natural neurotransmitters in healthy perception and cognition

Question 4

What are the effects of psilocybin that have been found?

Answer 4

• Increase of religious experience
• ## altered states of consciousness - perceptual awareness and attention

Question 5

How are hallucinogens thought to work?

Answer 5

• 5-HT2a receptor!!!!!
  activates it out of proportion to other systems.
• Corticothalamic loops:
  Hallucinogens cause an increase in excitation in the cortex, and hence, an increase in the amplitude and frequency of activity of neurons travelling from the cortex to thalamus. It is theorised that hallucinogens disrupt corticothalamic loops through neurons becoming overactive and sending incorrect information to the thalamus, producing a disturbance in thought and sensory processing.

Question 6

What does LSD do to the brain?

Answer 6

• MRI found increased blood flow to the visual areas.
• visual imagery correlated with increased visual cortex resting state func connectivity
• ego dissolution correlated with reduced default mode network integrity.

Question 7

What are methodological obstacles in studying meditation?

Answer 7

• many types of meditation, everyone does it differently
• many placebo ingredients such as having common goals, ingroup, strong belief that it’s helpful
• active controls also found to have similar benefits

Question 8

What are some benefits of meditation?

Answer 8

• large meta-analysis showed mindfulness-based cog therapy reduced relapse rate for depression - more severe depression = more benefit from MBCT
• controlling mind wandering
• meditators performed better in cog tasks, but when given an incentive, difference between experienced and unexperienced meditators were eliminated

Question 9

What did binocular rivalry show after monks meditated?

Answer 9

• Meditation appears to slow perceptual rivalry switching
• effect is specific to one-point meditation
• supports introspective reports of monks that they are able to control and stabilise the contents of their consciousness.