Neurotransmitters

Studies

Antonova (2011) Terms to define

• Neurotransmitters

• Agonist

• Antagonist

• Acetylcoline

• Scopolamine

• Exitatory synapse

• Inhibitory synapse

Antonova (2011) Aim

To see if scopolamine affected hippocampal activity in the creation of spatial memory

Antonova (2011) Procedure

• Sample of twenty healthy male adults

• Double-blind procedure

• Participants were randomly allocated to one of two conditions, 1. Injected with scopolamine, 2. Injected with a placebo, aproximately 90 mins before the experiment

• They were trained in the game to make sure they were comfortable with the controls and understood the rules

• The participants were put into an fMRI where they were scanned while playing a virtual game called “arena task”

• With the game the researchers aimed to observe how participants were able to create spatial memories

• The goal of the game is for the participants to go around the arena until they reach a pole

• After learning where the pole is located, the screen would go blank for 30 secs, during this time the participants were told to actively rehearse how to get to the pole

• They would then regenerate in a different starting spot in the arena and they had to find the pole again using their spatial memory

• The participants’ brain activity was measured for six trials

• They returned 3-4 week later and redid the test, reciving the opposite treatment (scopolamine or placebo) to the original study (repeated measures design)

Antonova (2011) Results

• Participants that were injected with scopolamine had a significant reduction in the activation of the hippocampus compared to when they recieved a placebo

• Acetylcholine plays a critical role in encoding spatial memory

• Scopolamine acts as an antagonist ffor acetylcoline as it reduces or blocks the effects of acetylcholine

Antonova (2011) Evaluation

Rogers and Kesner (2003) Terms to define

• Neurotransmitters

• Agonist

• Antagonist

• Acetylcholine

• Scopolamine

• Exitatory synapse

• Inhibitory synapse

Rogers and Kesner (2003) Aim

To determine the role of acetylcholine in the formation of spatial memory

Rogers and Kesner (2003) Procedure

• 30 rats acclimated to a Hebb Williams maze using food

• Randomly allocated to one of two conditions. 1. injected with scopolamine, 2. injected with a saline solution (placebo) ten minutes before running the maze

• The placebo injection was used to make sure that the fact of gettin an injection alone wwas not responsible for any change in memory (confounding variable)

• Both injections were made directly to the hippocampus

• Encoding of memory was assessed by the average number of errors made on the first five trials of day 1 compared to the last five trials of day 1

• To asses retrieval they used the average number of errors made on the first five trials of day 2 compared to the last five of day 1

Rogers and Kesner (2003) Results

• The scopolamine grouo took longer and madde more mistakes in learning the maze

• It did not appear to have an effect on retrieval of memories that had already been created

• It appears that acetylcholine may play an important role in the consolidation of spacial memory

Rogers and Kesner (2003) Evaluation

• Strengths:

  • Controlled environment: Rats were acclimated, reducing extraneous variables.

  • Random allocation: Ensured comparability between groups.

  • Placebo control: Isolated the effects of scopolamine.

  • Clear measurements: Defined encoding and retrieval through error counts.

  • Ethical adherence: Likely followed animal welfare guidelines.

• Limitations:

  • Limited generalizability: Results may not apply to humans.

  • Low ecological validity: Maze task may not reflect real-life memory.

  • Narrow focus: Only acetylcholine was studied, excluding other factors.

  • Short-term focus: Long-term effects were not examined.

  • Potential confounders: Individual rat differences could affect results.

• Conclusions:

  • Acetylcholine is involved in memory encoding, but not retrieval.

  • Supports the role of acetylcholine in memory consolidation.

4o mini

Neurotransmitters and studies general evaluation

• Attributing complex human behaviors to neurotransmitters is reductionist, however it has led to drug treatments

• Research on animals may not be generalized to humans, eventhough there are clear similarities in physiological processes

• Lack ecological validity by not showing how the neurotransmitters functions in normal behavior