Neurotransmitters and the brain. Computer artwork showing the location (left) of the hypothalamus (pink and blue) in the human brain, and a neuron (nerve cell) connected to it (top) that terminates in a synapse (bottom). Inside the synapse neurotransmitters can be seen crossing from the neuron to another below it. Neurotransmitters are responsible for passing nerve impulses (messages) from one neuron to another across the gap (synapse) between them. There are many different neurotransmitters in the body each of which acts on different sets of neurons. Some of these are produced by the hypothalamus.