The synaptic cleft is a small gap between two neurons, specifically between the axon terminal of one neuron and the dendrite of another. This space is crucial for the transmission of signals in the nervous system. When a nerve impulse reaches the axon terminal, it triggers the release of neurotransmitters, which are chemical messengers. These neurotransmitters travel across the synaptic cleft and bind to receptors on the receiving neuron's surface. This binding can either stimulate or inhibit the generation of a new nerve impulse in the receiving neuron, allowing for communication between neurons and the processing of information in the nervous system.