known as the synaptic cleft. (4) The neurotransmitters bind to receptor sites on ion channels in the postsynaptic membrane, causing them to open. (5) Ions flow into the postsynaptic neuron ...

Between impulses the transmitter molecules are rapidly removed from the synaptic cleft to prevent continuous ... reabsorbed back into the presynaptic neuron and restored inside a vesicle ready ...

This results in enough neurotransmitter being diffused across the synaptic cleft to trigger the impulse in the postsynaptic neuron. This process is called summation.