Neurotransmitters - Psychology | International Baccalaureate

Neurotransmission

Transfer of electro-chemical signals between neurons.

Neurotransmission Process

1. Stimulus triggers a neuron, forming an action potential which travels through the axon.

2. The action potential reaches the axon terminal, resulting in terminal buttons releasing vesicles filled with neurotransmitters.

3. The neurotransmitters are released into the synapse and the signal is either:

   a. Blocked

   b. Carries the action potential on.

4. The neurotransmitters bind with receptor sites on the post-synaptic neuron.

5. The neurotransmitters are released back into the synapse and are either:

   a. Reabsorbed into the pre-synaptic neuron.

   b. Dissolved by enzymes

Agonist

A chemical/substance that causes a post-synaptic neuron to fire.

Antagonist

Substances that inhibit action potential by binding to a receptor site instead of a neurotransmitter.

Endogenous

Naturally occuring chemical/substance within the body.

Exogenous

A chemical/substance introduced from outside the body which mimic natural neurotransmitters.

Scopolamine

An antagonist for actylcholine receptor sites, and interfers with memory formation.

Acetylcholine (ACh)

An endogenous agonist which plays a key role in forming new memories and spatial memories in the hippocampus.

Testability and Empirical Evidence of Theory

• Theory can be tested using fMRI or using antagonists.

• Experiments Through Animals —> Cause-and-Effect

• Correlative Through Humans —> Cause-and-Effect can’t be inferred.

Application of Theory

• Drugs have been made to slow down the breakdown of ACh for Alzheimer patients.

Antonova (2011)

Study shows that scopolamine interfers with the creation of spatial memories.

Rogers and Kesner (2003)

Study shows that acetylcholine plays an important role in forming spatial memories.