Nerve synapse, illustration. When an electrical signal reaches the junction (synapse) between two neurons, the pre-synaptic neuron releases chemical messengers (neurotransmitters) into the gap between the neurons (synaptic cleft). These neurotransmitters bind to receptors on the post-synaptic neuron, which changes the membrane's excitability and triggers an electrical impulse. This process allows for the transmission of nervous signals from one neuron to the next.