1. Action Potential Arrival: An action potential arrives at the presynaptic terminal. 2. Calcium Influx: Voltage-gated calcium channels open, allowing calcium ions to enter the presynaptic neuron. 3. Vesicle Fusion: Increased intracellular calcium triggers synaptic vesicles to fuse with the presynaptic membrane. 4. Neurotransmitter Release: Neurotransmitters are released into the synaptic cleft. 5. Receptor Binding: Neurotransmitters bind to receptors on the postsynaptic membrane. 6. Postsynaptic Response: The binding of neurotransmitters to receptors causes ion channels to open, leading to a change in the postsynaptic membrane potential, known as an excitatory postsynaptic potential (EPSP).
