COLLEGE PARK, Md. -- New research shows our brains are a lot more chaotic than previously thought, and that this might be a good thing. Neurobiologists at the University of Maryland have discovered information about how the brain processes sound that challenges previous understandings of the auditory cortex, which had suggested an organization based on precise neuronal maps. In the first study of the auditory cortex conducted using advanced imaging techniques, Patrick Kanold, assistant professor of biology, Shihab Shamma, professor of electrical and computer engineering, and Sharba Bandyopadhyay, post-doctoral associate, describe a much more complex picture of neuronal activity. Their findings are published in the January 31 online edition of Nature Neuroscience.
All our knowledge of how the brain really works has been based on taking a small sampling of all available neurons and making inferences about how the other neurons respond, Dr. Kanold explains. "This is like showing someone who wants to know how America looks, 'Here is one person from New York City and one person from California.' You don't get a very good picture of what the country looks like from that sampling," says Kanold, originally from Germany.
In contrast, Kanold and colleagues were able to look at the activity of all the neurons in a large region of the auditory cortex simultaneously. To get the highest resolution picture to date of how auditory cortex neurons are organized, the researchers used a technique to fill neurons in living mice with a dye that glows brightly when calcium levels rise, a key signal that neurons are firing. They then selectively illuminated specific regions of the cortex with a laser and measured the neuronal activity of hundreds of neurons in response to stimulation by simple tones of different frequencies.
This "in vivo 2-photon calcium imaging" technique was developed by German researchers and advanced by Harvard scientis
|Contact: Kelly Blake|
University of Maryland