Researchers at The Rockefeller University have shown for the first time in mice how the brain processes signals from pheromones, essential chemicals used by animals to communicate with each other. Reported in the April 16 issue of Cell, the findings provide the first look at the "wiring diagram" of the accessory olfactory system and show that it differs dramatically from the wiring diagram for the main olfactory system, which all mammals, including humans, use to detect smells.
"We have elucidated for the first time the wiring diagram of the accessory olfactory system in mammals, and we have shown that is more complex than the main olfactory system," says senior author Peter Mombaerts, M.D., Ph.D., assistant professor and head of the Laboratory of Vertebrate Developmental Neurogenetics at Rockefeller. "We think that the complex wiring of the accessory olfactory system reflects the need for the brain to recognize blends of molecules, rather than the individual odorant molecules recognized by the main olfactory system."
Scientists think the accessory olfactory system, also known as the vomeronasal system, is involved in animal communication. Neurons located in a structure called the vomeronasal organ project their axons to a specialized part of the olfactory bulb--the accessory olfactory bulb. The olfactory bulb is the first relay station of the olfactory system, where information is collected, integrated and processed. When the vomeronasal organ is removed from animals, they undergo profound changes in mating behavior and aggression.
In the Cell paper, Ivan Rodriguez, Ph.D., and Paul Feinstein, Ph.D., along with Mombaerts used genetic manipulation techniques to determine the wiring diagram of the accessory olfactory system and found pronounced differences from the diagram of the main olfactory system.
First, the researchers found that all the neurons that express the same
pheromone receptor project their axons to multiple targets in the accessor
Contact: Joseph Bonner