Neuron signal CGI image to download.  In the nervous system, neurons usually communicate by releasing neurotransmitters across tiny gaps called synaptic clefts. One neuron can send signals to hundreds of thousands of other neurons. This is accomplished by a presynaptic neuron releasing a neurotransmitter molecule, which then attaches to receptors on the surface of the postsynaptic neuron. The neurotransmitter is released from the presynaptic terminals, which can branch out to reach multiple postsynaptic neurons.