Neuroscientists commonly believe that the way the brain processes information is similar to climbing a pyramidstarting from the bottom and working up to the top. All of the sensory systems have a large number of low-level cells that do very simple things (forming the base of the pyramid), and then they feed their results to brain areas higher up the pyramid. The brain cells in these "higher" regions begin to reflect abstract concepts, such as the shape of human faces, in the visual system or melodies in the auditory system. The brain areas related to our conscious perception of the world are presumably at the top of pyramid.
However, the Case Western Reserve University researchers found that the brain circuit had the ability to change with experience was unexpectedly a connection from high in the pyramid (the olfactory cortex) back to a lower level (the olfactory bulb).
One of the implications of Strowbridge and Gao's work is that the brain may learn about different smells by having higher brain areas first make a prediction about which scent it might be, and then test that prediction against the actual sensory data coming into the brain.
"Our work suggests that there is much more talking back-and-forth between higher and lower brain areas during olfactory learning," continued Strowbridge. "We are just beginning to explore the function of the feedback circuits that inform low-level parts of the brain, like the olfactory bulb, about predictions made by higher-order brain regions. The 2-photon microscope used in this study is an ideal tool to ask what these different brain circuits are actually doing."
Previous studies had suggested that the circuit changes associated with olfactory learning, such as sheep learning to recognize their own lambs though their characteristic scents, invol
|Contact: Christina DeAngelis|
Case Western Reserve University