In the nervous system, information is carried by electrical impulses from sensory neurons to the brain, from the brain to motor neurons, and within the neurons of the brain itself. A synapse is a connection between two neurons, and allows the transmission of electrical impulses from one neuron to the other. In order to do this, the electrical impulse must be converted into a chemical signal. When the electrical impulse travels down the pre-synaptic neuron it stimulates the release of molecules into the synapse. These molecules can then diffuse towards the post-synaptic neuron, and interact with its receptors in order to cause an electrical impulse in that neuron, which can then carry on to the next synapse - effectively conveying the information.