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Point of View

Researchers from around the world gathered May 13-14 at Columbia to discuss the latest discoveries on the brain and the mind spanning the entire spectrum of neuroscience, from the atomic level up to higher order systems that construct consciousness.

Organized by Dr. Thomas Jessell, professor of biochemistry and molecular biophysics, and Dr. Joanna Rubinstein, senior associate dean for institutional and global initiatives at Columbia University Medical Center, the day and half day symposium was divided into three half-day sessions: Brain Structure, Brain Function and Disease, and Biology of the Mind.

In the first session, Brain Structure, Dr. Gerald Fischbach, executive vice president and dean, said that despite the brain's great complexity, research is on the verge of translating basic brain research into treatments for neurological disorders.

Rockefeller University's Dr. Roderick MacKinnon, the 2003 Nobel Prize winner in Chemistry, discussed his own basic research, which has revealed the structure and function of the neurons' ion channels.

Though these ion channels are the brain's electrical impulse generators, the impulses must be sent through the brain's highly organized circuits to control movement, cognition, and consciousness. Though many circuits are not understood, Dr. Jessell said, he outlined his progress on circuits that control movement, showing that although the basic circuitry is genetically hard-wired, the experience of learning to walk or play the violin refines the circuits.

Dr. Eric Kandel, University Professor of Psychiatry, Physiology & Cellular Biophysics, and Biochemistry & Molecular Biophysics and 2000 Nobel Prize winner showed the audience how those circuits are refined during learning. Changes in synapses — which connect all neurons — occur during learning, he said, and those changes were even taking place in each member of the audience as he spoke. "You will walk out of the symposium with a different brain than you walked in with," Dr. Kandel said.

Dr. Richard Axel, University Professor of Biochemistry and Molecular Biophysics spoke about a different brain circuit — the olfactory system of the fruitfly.

Dr. Axel is working to understand how senses — such as smell — are derived from neuronal activity, which, after all, only function in time and space.

In the second session, Brain Function and Disease, scientists discussed how new techniques in brain imaging are changing the way we think about brain disorders, which afflict one in seven people.

Initially, schizophrenia was thought to stem from brain changes acquired in adulthood, said Dr. Judith Rapoport, a child psychiatrist at the National Institutes of Health. "But with brain imaging we're finding that children have problems even before the onset of schizophrenia." Her studies show that while the brains of all children lose brain mass through childhood, children who eventually develop schizophrenia lose more.

Dr. Nora Volkow, director of the National Institute on Drug Abuse, uses brain imaging to understand why addicts are unable to control drug intake. Her PET scans of brains of both addicts and non-addicts suggest that high levels of dopamine receptors in one part of the brain can prevent people from becoming addicted. "What's surprising is that this happens in the frontal cortex, which is not normally believed to be involved in addiction," she said. "The frontal cortex weighs the value of one thing to another, so in designing treatments we need something that will alter motivation."

In the final session, "Biology of Mind," speakers explored how the brain constructs the mind.

In studying decision-making, for example, neuroscientists have traditionally emphasized the effects of sensory stimuli on the outcome of the process. "But this is an impoverished view," Dr. William Newsome, a professor of neurobiology at Stanford said. "An organism's prior experience or beliefs concerning the "value" of the alternative choices can influence decisions even more so than sensory input." Dr. Newsome described how neuronal recordings from monkeys making decisions are helping scientists discover which neural circuits are used to calculate value and how values influence decision-making.

Two speakers presented views on the biological basis of consciousness. Philosopher John Searle from Berkeley believes that the quest to understand how the conscious mind functions is a viable goal. Dr. Searle drew an analogy with the glass of water that sat before him on the podium: Just as liquidity is a higher order feature of the behavior of individual water molecules, the mind is a higher order feature of the activity of neurons. "The brain causes minds," he said.

Dr. Christof Koch, a neuroscientist at Caltech added: "Many people think consciousness can't be addressed by scientific methods. But we should be cautious of that assertion since we've made that mistake several times in history."

–Susan Conova