Scientists at the Salk Institute and UC San Diego have for the first time identified differences in the DNA of individual neurons in the human brain.
The research, published in the journal Science on Thursday, is considered a critical development in identifying how neurons differ and what functions they control, eventually enabling the compilation of a “parts list” for the brain.
“Our research shows that we can clearly define neuronal types based on their methylomes,” says Margarita Behrens, a Salk senior staff scientist and co-senior author of the new paper. “This opens up the possibility of understanding what makes two neurons—that sit in the same brain region and otherwise look similar—behave differently.”
Each cell’s methylome—the pattern of chemical markers made up of methyl groups that stud its DNA—gave a distinct readout that helped the Salk team sort neurons into different types.
The team focused on the frontal cortex, the area of the brain responsible for complex thinking, personality, social behaviors and decision making. They isolated 3,377 neurons from the frontal cortex of mice and 2,784 neurons from the frontal cortex of a deceased 25-year-old human.
“There are hundreds, if not thousands, of types of brain cells that have different functions and behaviors and it’s important to know what all these types are to understand how the brain works,” says Chongyuan Luo, a Salk research associate and co-first author of the new paper, along with UC San Diego graduate student Christopher Keown. “Our goal is to create a parts list of both mouse and human brains.”
The human brain has an estimated 100 billion neurons that control its functions and produce thought and consciousness.
