Psychology / Unit 2: The Brain and Behavior
2.2 Neurotransmitters and the Synapse
Notes
Neurons do not touch. They communicate across a tiny gap called the synapse.
- An action potential reaches the axon terminal and releases neurotransmitters, which cross the synapse and fit receptors on the next neuron.
- Leftover neurotransmitter is cleared by reuptake (taken back into the sending neuron) or broken down.
| Neurotransmitter | Main roles |
|---|---|
| Acetylcholine | Muscle movement, learning and memory |
| Dopamine | Movement, reward, motivation |
| Serotonin | Mood, sleep, appetite |
| GABA | Main inhibitory messenger; calms activity |
| Glutamate | Main excitatory messenger; learning |
| Endorphins | Reduce pain, feelings of pleasure |
- Some substances act as agonists (mimic or boost a neurotransmitter) or antagonists (block it).
Practice
What is the synapse?
Neurotransmitters cross the synapse from one neuron to the next.
Which neurotransmitter is linked to muscle movement and memory, and is lost in people with Alzheimer's disease?
Acetylcholine is involved in muscles and memory; Alzheimer's is associated with reduced levels.
A drug blocks receptors so a neurotransmitter cannot have its normal effect. The drug is acting as:
Blockers of a neurotransmitter's action are antagonists.
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