Acquisition of Innate Odor Preference Depends on Spontaneous and Experiential Activities During Critical Period

Animals possess inborn ability to recognize certain odors, which enables them to seek food, avoid predators and find mates even in the absence of prior experiences. Here we report that the acquisition of innate odor recognition requires spontaneous neural activity and is influenced by sensory experience during early postnatal development. Genetic silencing of mouse olfactory sensory neurons during the critical period has little impact on odor sensitivity, odor discrimination and recognition later in life. However, it abolishes innate odor preference and alters the patterns of activation in brain centers associated with odor preference. Moreover, exposure to an innately aversive odor during the critical period abolishes aversion in adulthood in an odor specific manner. The loss of innate aversion is associated with broadened projection of OSNs expressing the cognate receptor such that they innervate ectopic glomeruli in the olfactory bulb. These results indicate that a delicate balance of neural activity is required during critical period in establishing innate odor preference and that ectopic projection is a convergent mechanism to alter innate odor valence.