Anterograde tracing

Anterograde tracing is a research method that is used to trace axonal projections from the soma (cell body), to their point of termination at the synapse. A hallmark of anterograde tracing is the labeling of the presynaptic and the postsynaptic neurons. The crossing of the synaptic cleft is a vital difference between the anterograde tracers and the dye fillers used for morphological reconstruction. The complementary technique is retrograde tracing, which is used to trace neural connections from their termination at the synapse to their source at the cell body. Both anterograde and retrograde tracing techniques are based on the visualization of the biological process of axonal transport.

The anterograde and retrograde tracing techniques allow the detailed descriptions of neuronal projections from a single neuron, or from a defined population of neurons to their various targets throughout the nervous system. These techniques allow the "mapping" of connections between neurons in a particular structure such as the eye, and the target neurons in the brain. Much of what is known about connectional neuroanatomy was discovered through the use of the anterograde and retrograde tracing techniques.