NEUROBIOLOGY:
Mapping Smells in the Brain
Marcia Barinaga
Each sensory system has a code for the information it receives. The olfactory system, for example, encodes odors by chemical composition. Now, a team of neurobiologists has devised a powerful new way to read the brain's smell code. Each of the thousands of little clusters of neurons in the brain's olfactory bulb called glomeruli receives input from a specific type of olfactory neuron in the nose. That means each smell should activate a unique pattern of glomeruli--the code for that smell. In the July issue of Neuron, neuroscientists now report that they have used an optical imaging technique to see those patterns--the first time that's been done in living mammals. The technique should offer neurobiologists a rare opportunity to examine and manipulate the ways the brain processes specific sensory information.