AMPA glutamate receptor activated by glutamate. Computer illustration showing the molecular structure of an AMPA glutamate receptor (blue), in the membrane (bottom, horizontal) of a neuron (nerve cell), being activated by the neurotransmitter glutamate (orange). Neurotransmitters carry nerve impulses (signals) from one neuron to the next, across a gap known as the synapse. Here, activation causes the receptor to transport cations (red) into the neuron (bottom). This postsynaptic excitation is what transmits the nerve impulse and is important for neural communication, memory formation, learning and regulation.