<P> Axon terminals (also called synaptic boutons or terminal boutons) are distal terminations of the telodendria (branches) of an axon . An axon, also called a nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses called action potentials away from the neuron's cell body, or soma, in order to transmit those impulses to other neurons, muscle cells or glands . </P> <P> Neurons are interconnected in complex arrangements, and use electrochemical signals and neurotransmitter chemicals to transmit impulses from one neuron to the next; axon terminals are separated from neighboring neurons by a small gap called a synapse, across which impulses are sent . The axon terminal, and the neuron from which it comes, is sometimes referred to as the "presynaptic" neuron . </P> <P> Neurotransmitters are packaged into synaptic vesicles that cluster beneath the axon terminal membrane on the presynaptic side of a synapse . The axonal terminals are specialized to release the neurotransmitters of the presynaptic cell . The terminals release transmitter substances into a gap called the synaptic cleft between the terminals and the dendrites of the next neuron . The information is received by the dendrite receptors of the postsynaptic cell that are connected to it . Neurons don't touch each other, but communicate across the synapse . </P>

The blank is the tiny gap between the axon terminal and the next neuron