Synapse Gap

The 20-nanometer void between two nerve cells/Biology & Ecosystems

A synaptic cleft is the tiny gap between two neurons across which chemical neurotransmitters diffuse to transmit signals. The gap is only about 20 nanometers wide. Neurotransmitter molecules cross this gap in about 0.5 milliseconds. The human brain contains roughly 100 trillion synapses, and the strength of these connections changes with learning and experience through a process called synaptic plasticity. Each synapse is so small that about 50,000 could fit across the width of a human hair.