Z. Josh Huang, Ph.D., a professor at Cold Spring Harbor Laboratory (CSHL), used his NARSAD Distinguished Investigator Grant to help solve a decade’s long puzzle about where ‘chandelier cells’ come from and how they work in the brain. Chandelier cells are a class of inhibitory cells that only exist in the cerebral cortex, the area of the brain that helps make us "human” as it is responsible for language, thought, sensation and spatial reasoning. The cells are called chandelier cells due to their resemblance to old-fashioned candlesticks.
Relatively little is known about chandelier cells. They were first noticed about 40 years ago, and they are found individually among great crowds of excitatory cells in the cortex called pyramidal neurons. Their relatively short branches make contact with these excitatory cells—a single chandelier cell connects, or "synapses," with as many as 500 pyramidal neurons.
Dr. Huang notes that one cell that can regulate the messages of 500 others in its vicinity is one that we need to know about if we want to understand how brain circuits work. He also points out that the number and connective density of chandelier cells is diminished in schizophrenia.
After three years of painstaking work that has involved using new technologies to identify and trace neural cell progenitors in ways not previously possible, and to track them as they migrate to positions in the maturing cortex, Huang and colleagues, including Dr. Hiroki Taniguchi, now at the Max Planck Florida Institute, have demonstrated that chandelier cells are born in a previously unrecognized portion of the embryonic brain, which they have named the VGZ (ventral germinal zone). Their study was published online November 22 in Science Express.
"To know the identity of a cell type in the cortex is in effect to know the intrinsic program that distinguishes it from other cell types," Huang says. "In the broadest terms, we are learning about those aspects of the brain development that make us human. ’Nurture,' or experience, also has a very important role in brain development. Our work helps clarify the 'nature' part of the nature/nurture mystery that has always fascinated us."