Neurotransmitters play a crucial role in synaptic transmission by facilitating communication between neurons. When an electrical impulse reaches the end of a neuron, neurotransmitters are released into the synaptic cleft, where they bind to receptors on a neighboring neuron. This binding either excites or inhibits the receiving neuron, thus propagating or dampening the signal. The precise balance of neurotransmitter activity is essential for maintaining proper nervous system function.