Neurotransmitters

Question 1

Define neurotransmitter

Answer 1

• chemical messengers which transmit information from one neuron to another.
• can be affected by agonists (chemicals that enhance the action of neurotransmitters) and antagonists (chemicals that counteract neurotransmitters).

Question 2

Describe neurotransmission

Answer 2

• an electrical signal comes down from the axon and generates action potential
• synaptic vesicles contain neurotransmitters to move towards pre-synaptic membrane
• neurotransmitters diffuse across the gap and attaches(binds) to the post-synaptic membrane(complementary shapes)
• after crossing the synapse, neurotransmitters fit into receptor sites on the post-synaptic membrane, like a key in a lock
• reuptake–reabsorption of neurotransmitter

Question 3

Define inhibitory neurotransmitters

Answer 3

• stop the impulse, preventing it from crossing the synapse.

- produce calming effects on the brain.

Question 4

Define excitatory neurotransmitters

Answer 4

• allow the impulse to cross the synapse.

- produce stimulating effects on the brain.

Question 5

Study 1

Answer 5

Martinez and Kesner (1991) - acetylcholine & memory formation

Question 6

Aim 1

Answer 6

to measure the role of acetylcholine in the formation of spatial memory.

Question 7

Procedure 1

Answer 7

• 30 rats were placed in the maze individually and completed the maze (maze had a reward of food at the end).
• rats were given their respective treatments 10mins before running the maze.
  1. injected with scopolamine (antagonist - blocks the ACH receptor sites and inhibits response)
  2. not injected or altered in any form (control).
• time taken for individuals rats to complete the maze were recorded.

Question 8

Results 1

Answer 8

• rats in condition 1 took longer to complete the maze.
• Acetylcholine may plays an important role in the consolidation of spatial memory as the rats in control group (with more ACH) took shorter time to complete the maze.

Question 9

Evaluation 1

Answer 9

• lab enviroment: high scientific rigour, results are highly accurate.
• strong applications - the development of treatment form dementia or alzheimer’s disease.
• animals selected are similar to humans (can serve as models for human physiology and behaviour).
• a reductionist approach to understand memory - didn’t explain the complexity of types and process of memory consolidation

Question 10

Study 2

Answer 10

Antonova et al (2011) - acetylcholine on encoding spatial memory

Question 11

Procedure 2

Answer 11

• participants were 20 male adults with a mean age of 28.
• they were randomly allocated to the two conditions respectively (70-90mins before the experiment, they were either):
  1. injected with scopolamine
  2. injected with placebo.
• the participants were then put into an fMRI where they were scanned while playing “Arena task” - a virtual reality game in which the participants need to navigate around an “arena” with the goal of reaching a pole.
• it will then go blank for 30s.
• when the arena reappeared, the participants would have to use their spatial memory to determine how to get to the location o the pole.

Question 12

Results 2

Answer 12

• participants injected with scopolamine (antagonist) demonstrated a significant reduction in the activation of the hippocampus compared to when they received a placebo.
• thus ACH could play a key role in the encoding of spatial memories in humans.

Question 13

Evaluation 2

Answer 13

• double-blind procedure: control for research & participant bias.
• the sample size was small: need replication to decide whether the results are reliable.
• no ethical concerns as no physical and psychological harms were done to the participants.

Question 14

Behaviour

Answer 14

acetylcholine on encoding spatial memory.

Question 15

Aim 2

Answer 15

to measure the role of acetylcholine in the formation of spatial memory