...information from a region (anterograde tracer, Fig. 1B). Tracers are typically delivered to a particular... either trace downstream from the soma (neuron cell body) toward the axon (anterograde tracer) or upstream...making them useful tracers, but finding a virus that works well for retrograde tracing can be difficult....brain works.
There are two methods of neuronal tracing (Fig. 1): one to visualize neurons that send information...information to a region (retrograde tracer, Fig. 1A), and another to visualize neurons that receive information...from the axon terminals to the soma (retrograde tracer) (Fig. 2).
Viruses as neuronal scalpels
Viruses...transport and can therefore perform retrograde tracing, but often at the cost of toxicity, low expression...