Synaptic delay refers to the time it takes for a signal to pass across a synapse in the nervous system. This delay occurs during the transmission of information from one neuron to another, typically involving the release of neurotransmitters from the presynaptic neuron, their diffusion across the synaptic cleft, and the subsequent activation of receptors on the postsynaptic neuron.

The synaptic delay usually lasts about 0.5 to 1 millisecond and is a key factor in determining how quickly neural circuits can process information. This delay can be influenced by factors such as the type of neurotransmitter, the distance across the synapse, and the speed at which the neurotransmitters are released and received.