Capitalizing on the latest technology, neuroscientist Liqun Luo has found a new way to trace the intricate neural connections that blossom in the developing brain. For the last century, neuroanatomists have turned to a tried-and-true technique called Golgi staining to glimpse inside the brain and explore how neural circuits are organized and maintained. Like his colleagues, Liqun Luo also seeks to understand fundamental issues of neural structure, connectivity, and development. But he's bringing new tools to the task.
Luo developed a genetic alternative to Golgi staining, which randomly labels a small population of neurons in preserved tissue. Luo's technique, mosaic analysis with a repressible cell marker (MARCM), offers more control and an important genetic advance—scientists can label small groups of neurons in live animals. They also can genetically manipulate labeled neurons to track the effects of deleting or expressing a gene. Luo's goal is to use MARCM and similar tools to learn how neural circuits assemble during development and how they contribute to sensory perception. He is focusing on fruit fly and mouse models.
Using MARCM, Luo learned that neurons in the fruit fly brain prune their axons (branches of growing nerves) much like what happens when neurons in the mammalian nervous system are injured. Fruit flies also use glial cells—cells that wrap around and protect neurons—to absorb unneeded axons. His lab found striking structural similarities in olfactory projection neurons in different animals. In the fly brain, these neurons form an orderly, complex map. Luo's lab is studying how that map is assembled during development and is identifying neural circuits responsible for olfactory behavior—the sense of smell. His team is perfecting a similar genetic tool to study mice.
Luo began to study science in China, with an interest in physics and molecular biology. He attended graduate school at Brandeis University, where the strong community of neuroscience researchers piqued his interest in the field. He hasn't looked back.