Electrical synapses are found in all nervous systems, including the human brain. The membranes of the two communicating neurons come extremely close at the synapse and are actually linked together by an intercellular specialization called a gap junction. Gap junctions contain precisely aligned, paired channels in the membrane of the pre- and postsynaptic neurons, such that each channel pair forms a pore. Electrical synapses thus work by allowing ionic current to flow passively through the gap junction pores from one neuron to another. Because passive current flow across the gap junction is virtually instantaneous, communication can occur without the delay that is characteristic of chemical synapses.