Related Theory A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of a pre-synaptic neuron and a post-synaptic neuron, which may or may not be separated by a gap called synaptic clefi. At electrical synapses, the membranes of pre-and posi-synaptic neurons are in very close proximity. Electrical current can flow directly from one neuron into the other across these synapses. Impulse transmission across an electrical synapse is always faster than that across a chemical synapse.