Exploring the brain's circuitry
December 13th 2009 20:25
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Wendy Plump
SPECIAL TO THE TIMES
Next time you look up at the night sky you might dispense with thoughts about stars and nebulae and the insignificance of human life on our odd little planet. You might think instead about neurons. As in, how many more interactions they can fire up in your brain -- more interactions, in fact, than there are stars in the known universe.
Neuroscientist Jonathan Cohen, a professor of psychology at Princeton University, likes to frame his astonishment at the human brain with this fact. His career has been devoted to figuring out how the brain works. The astronomy metaphor is an apt way of introducing both the awe of the subject, he says, and its basic, almost overwhelming challenge.
"Let me give you some numbers," Cohen, 54, says from his comfortable book-lined office in Princeton's psychology department. "The brain is made up of about a hundred billion neurons, the cells that are thought to be the critical ones doing the things that underlie our thinking and our feeling.
"Each of those neurons makes contact with at least a thousand other cells -- and often more, sometimes 10 thousand other cells. So now you do the computations. How many different possible circuits can you make with 100 billion elements, each of which connects with a thousand others? There are many more than a hundred trillion connections there. And that's in each person's head.
"Well then," he adds, putting his finger on the daunting nature of his research, "how do we figure out how it works?"
How indeed. One of the ways is to found the Princeton Neuroscience Institute, which Cohen in the psychology department and colleague David Tank in the molecular biology department have recently accomplished. Sort of. An endowment for the institute is being set up. A Ph.D. program has been codified. Faculty have been hired. Blueprints lie rolled up on professor Cohen's desk. Critically all that remains unfinished is the building itself, for which funding is still coming in.
The institute's mission has also been set down in grand purpose: To bring theoreticians and experimentalists together under one roof to puzzle out the workings of the most complex instrument on the planet.
Oddly, very little is understood about how the human brain actually works, says Cohen. Research in the past has focused on behavioral experiments, or on dicing up the frontal lobes of other mammals and formulating theories on what it all means. But few have looked deeply at what is going on in the brain's software, in the neural pathways that conduct signals that prompt us to behave and respond one way or another.
With the advent of technology -- magnetic resonance imaging (MRIs) for example and computers complex enough to simulate behavior and cast those behaviors into code -- the magnitude of the questions has broadened. But so has the capacity to explore them more completely.
At the institute, Cohen says, neuroscientists can begin to bridge the gap between the research of molecular and cellular biologists who study the brain's physical "components," psychologists who study behavior and thought processes and theorists who can tease out of the data some legitimate ideas of what is going on inside our heads.
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