The unexposed nostril detected the androstenone at the same level as the exposed nostril. Because there is no neural link between the nostrils at the peripheral level, the researchers concluded that this exposure-induced learning must have occurred in the olfactory structures in the brain that share information from both nostrils.
"Since the unexposed nostril learned just as well, the brain is definitely involved. This contradicts a previous theory that olfactory learning occurred in the nose only," said Sobel, a member of UC Berkeley's Health Sciences Initiative, a broad effort bringing together campus researchers from many disciplines to work on health problems of the 21st century.
"Our results suggest there must be a central component in the brain at work," Sobel said, though he added the researchers have not ruled out peripheral neural changes occurring as well. Ongoing research is being conducted to determine if peripheral neural plasticity - the nervous system acquiring a capability it didn't have before - is involved.
In children, the nervous system is constantly changing and developing, "but in adults, it's a question as to how much it can change," Sobel said. "If you want to repair a damaged nervous system, the best way to go about doing this is to figure out how it regenerates on its own."
Further studies by the team will investigate the difference between people who can learn to detect an odor through exposure to that odor and those who cannot. The researchers also will use Magnetic Resonance Imaging to localize regions in the brain to see where learning and change is occurring.
'"/>
Contact: Carol Hyman
cph@pa.urel.berkeley.edu
510-643-7944
University of California - Berkeley
23-Oct-2002