PRINCETON, N.J. – Fifty years from now, when Malia and Sasha are grandmothers, their father’s presidency might seem most consequential because of a small sum – $100 million – for studying something small. “As humans,” Barack Obama said when announcing the initiative to study the brain, “we can identify galaxies light-years away … but we still haven’t unlocked the mystery of the three pounds of matter that sits between our ears.”

Actually, understanding the brain will be a resounding success without unlocking the essential mystery, which is: How does matter become conscious of itself? Or should we say, how does it become – or acquire – consciousness? Just trying to describe this subject takes scientists onto intellectual terrain long occupied by philosophers. Those whose field is the philosophy of mind will learn from scientists such as Princeton’s David Tank, a leader of the BRAIN Initiative, which aims at understanding how brain regions and cells work together, moment to moment, throughout our lives.

If, as is said, a physicist is an atom’s way of knowing about atoms, then a neuroscientist like Tank is a brain cell’s way of knowing about brain cells. Each of us has about 100 billion of those, each of which communicates with an average of 10,000 other nerve cells. The goal of neuroscientists is to discover how these neural conversations give rise to a thought, a memory or a decision. And to understand how the brain functions, from which we may understand disorders such as autism, schizophrenia and epilepsy.

Biological causes have been determined for only about 3 percent of the disorders listed in the Diagnostic and Statistical Manual of Mental Disorders. With “mapping,” scientists may at last establish connections between neurotransmitters and particular mental disorders. This might influence how pharmaceutical companies direct their research. And treatments of post-traumatic stress disorders might benefit from learning how the mind erases disturbing memories.

Understanding the brain is, Tank says, different from the Human Genome Project. The latter simply sequenced, and made straightforward extrapolations, concerning a well-defined group of 3.1 billion “letters” that comprise the “alphabet” that determines the growth of a human being from a single cell to a complex human being. We are learning what each letter does, if not yet how. In the case of the brain, “mapping” is not just trying to ascertain what particular parts of the brain do in response to external events, but how the brain parts engage in “conversation” with each other, and how they can change over time.

Much brain activity – much thinking – is not, Tank notes, the result of external stimuli. So, is the brain conversing with – acting upon – itself? This internal conversation is at the core of who – and what – we are.

New technologies enable scientists to watch the brain in action, monitoring neural activity as it thinks. Even a decades-old technology, functional magnetic resonance imaging (fMRI) reveals, Tank says, “what parts of the brain are active in particular computations and behaviors.”

In 50 years, fMRI images will seem as crude as Magellan’s maps. We will understand thought processes with instantaneous cellular resolution, and hence the essence of what brains do, and what derails them.

Development of the transistor, progenitor of the Digital Age, required only advances in materials science. There is, Tank says, “no comparable base of knowledge for the brain” because there is no mechanistic understanding of how the brain works. Pharmacology is groping for therapeutic effects because drugs target particular receptors the workings of which are not understood. To the brain, small pills can be sledgehammers. Understanding brain dynamics will enable ever more precise chemical and other interventions.

If we had to think about combing our hair or making toast, we would never get out of the house in the morning. Habits enable us to function because neurons are “conversing” with networks involving thousands of other cells. But ethicists – and courts, and poets – will be warily watching what is learned about the neural basis of choices, habits, love and other important things.

Do we have bodies or are we bodies? What will become of the field of psychology as explorations of brain anatomy advances our understanding of how brain architecture influences, or even determines, behavior? “The devil made me do it” is no longer an exculpation. But what about “My brain circuitry made me do it”? Someday debates about free will may be resolved by understanding that we are responsible for our actions because we have “ownership” of three especially intricate pounds of matter.

© 2013, Washington Post Writers Group