Tracing the brain’s connections
A genetically modified version of the rabies virus is helping scientists at Harvard to trace neural pathways in the brain, a research effort that could help lead to treatments for Parkinson’s disease and addiction. As described in a paper published on June 7 in the journal Neuron, a team of researchers led by Naoshige Uchida, associate professor of molecular and cellular biology, used the virus to create the first comprehensive list of inputs that connect directly to dopamine neurons in two parts of the brain, the ventral tegmental area (VTA), known for processing reward, and the substantia nigra (SNc), known for motor control. “You may be familiar with the term connectome,” Uchida said. “The basic idea is we want to understand the brain in terms of connectivity and the various cell types. In this case, we’re examining long-range connections, that is, how other parts of the brain connect directly to dopamine neurons.” Dopamine neurons...