Visualizing neurotransmitter secretion at individual synapses.

To advance understanding of the brain, the ability to measure both nerve cell electrical spiking and chemical neurotransmission with high spatial resolution is required. In comparison to the development of voltage sensors and Ca(2+) indicator dyes over the past several decades, high resolution imaging of neurotransmitter (NT) release at single synapses has not been possible. In this Viewpoint, we discuss two recent developments toward this goal, namely, the design of fluorescent false neurotransmitters (FFNs) and optical neurotransmitter sensors.