Early olfactory learning induces an enhanced olfactory bulb response in young rats.

During postnatal days 1-18, pups were simultaneously exposed to an odor and reinforcing tactile stimulation similar to that normally received from the dam. Control pups received only the odor, only the stimulation, or neither of these stimuli. On postnatal day 19, pups that had previously received simultaneous odor and tactile stimulation displayed both a behavioral odor preference and an enhanced 2-deoxyglucose uptake in specific olfactory bulb glomeruli to subsequent presentation of that odor. These results suggest that early olfactory learning enhances the neural response to odors that have acquired attractive value.