A big step toward mapping the human brain

In the past few years, neuroscientists have embarked on several ambitious projects to make sense of the tangle of neurons that makes the human experience human, and an experience. In the UK, Henry Markram is leading the Human Brain Project, a $1.3 billion plan to build a computer model of the brain.
 
In the US, the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative hopes to, in its own nebulous way, map the dynamic activity of the noggin’s 86 billion neurons.
 
Now, the Allen Institute for Brain Science, a key player in the BRAIN Initiative, has launched a database of neuronal cell types that serves as a first step toward a complete understanding of the brain.
 
It’s the first milestone in the Institute’s 10-year MindScope plan, which aims to nail down how the visual system of a mouse works, starting by developing a functional taxonomy of all the different types of neurons in the brain.
 
“The big plan is to try to understand how the brain works,” says Lydia Ng, director of technology for the database. “Cell types are one of the building blocks of the brain, and by making a big model of how they’re put together, we can understand all the activity that goes into perceiving something and creating an action based on that perception.”
 
The Allen Cell Types Database, on its surface, doesn’t look like much. The first release includes information on just 240 neurons out of hundreds of thousands in the mouse visual cortex, with a focus on the electrophysiology of those individual cells: the electrical pulses that tell a neuron to fire, initiating a pattern of neural activation that results in perception and action.
 
Understanding those single cells well enough to put them into larger categories will be crucial to understanding the brain as a whole, much like the periodic table was necessary to establish basic chemical principles.