Biological Approach - The Brain and Behaviour - Neurotransmission

Question 1

Serotonin

Answer 1

• Monoamine, a group of neurotransmitters

Question 2

Depression

Answer 2

• Affective disorder

Question 3

Neurotransmitter

Answer 3

• A chemical that carries infromation between neurons

- Part of neurotransmission

Question 4

Neurotransmission

Answer 4

1. Starts at resting potential
2. Electrical impulse moves from the cell body, slong the
   axon to the presynaptic neuron (= action potential)
   - this allows vesicles (containing neurotransmitters) to
   move towards the cell membrane and fuse with it
3. Neurotransmitters are released in the synaptic space
   and bind with their respective receptors
   - this causes an electrical impulse in the postsynaptic
   neuron
   
   • this then travels to the cell body, carrying its
     information from the neurotransmitters
4. Once the neurotransmitters binded, they get released
   in the synaptic space
   - transporters carry them back to the presynaptic
   neuron
   
   • they then go back to vesivles and wait for another
     electrical impulse

Question 5

MAO-A

Answer 5

• An enzyme that breaks down neurotransmitters that are in the synaptic space

Question 6

Serotonin Hypothesis

Answer 6

• Low levels of serotonin affects depression

Question 7

PET Scan

Answer 7

• Positron Emission Tomography Scan
• Monitors glucose metabolism
  
  • patient injected with harmless dose of radioactive
    glucose
• Scans produce a coloured map of brain activity
• Function
  
  • Evaluates brain function
• May detect early onset of disease before it is evident on
  other imaging tests

Question 8

Meyer et al. (2006)

Answer 8

Aim:
- Investigate whether MAO-A levels in the brain are elevated during untreated depression

Pps:
- 17 healthy individuals
- 17 depressed indviduals with major depressive disorder
(MDD)
- had been medication free for min. 5 months

Procedure:
- PET-scan was made to measure amount of MAO-A in
different regions of the brain (e.g. prefrontal cortex,
hippocampus)

Results:
- MAO-A elevated in every brain region assessed for depressive pps (elevated on average by 34%)

Question 9

Agonist

Answer 9

• A chemical that mimics neurotransmitters and bind to their receptor in the post-synpatic neuron, amplifying the effect of the neurotransmitters
• E.g. LSD, an agonist that increases serotonin and dopamine flow

Question 10

Antagonist

Answer 10

• A chemical that inhibits receptor in the post-synpatic neuron and blocks them, reducing their effect
• Neurotransmitters cannot find to those receptors, therefore cannot send information to the post-synaptic neuron
• E.g. ketanserin (5-HT2A receptor antagonist)

Question 11

Inhibitory/Excitatory Synapse

Answer 11

Signals sent across excitatory synapses increase the activity of the receiving neuron, while signals sent across inhibitory synapses reduce neuron activity.

Question 12

Cognitive Bizarreness

Answer 12

• Dream-like waking imagery of impossible and irrealistic thoughts, feelings, characters, objects and events.

Question 13

Kraehenmann et al. (2017)

Answer 13

Aim:
- Test the hypotheses that LSD produces dreamlike waking imagery, and that thsi imagery depends on 5-HT2A receptor activation and is related to subjective drug effects

Pps:
- 25 health subjects

Proceudre

• Pps performed an audio-recorded guided mental imagery task 7 h after drug administration during 3 conditions
  
  • placebo
  • LSD
  • LSD + ketanserin
• Cognitive bizarreness of guided mental imagery reports was quantified
• State of consciousness was evaluated

Results:

• LSD, compared with placebo significantly increased cognitive bizarreness
• LSD induced increase in cognitive bizarreness was positively correalted with the LSD induced loss of self-boundaries and cognitive control
• Both LSD-induced increases in cognitive bizareness and changes in state of consciousness were fully blocked by ketanserin