NEONATAL OLFACTORY EXPERIENCE BOOSTS COGNITIVE PERFORMANCE

Interfering with environmental background during development has been shown to dramatically influence brain functions in adulthood. For example, environmental enrichment improves sensory perception and cognitive performance, maternal separation leads to memory deficits, and visual deprivation results in cross-modal sensory compensation. However, little is known about how olfaction early in life impacts cognitive processing and the function of underlying brain circuits. Previously, we provided the first evidence that patterns of activity in the olfactory bulb during a defined neonatal time window control the function of downstream cortical networks and modulate the development of cognitive abilities. Here, we investigate whether brief exposure to odor cues during early development can profoundly shape the cortical circuits and cognitive abilities along development. To this end, we introduced a neutral odorant into the homecage environment of mice during a defined period of neonatal development and monitored the long-term consequences of the exposure on the neuronal and network activity as well as behavior. Young mice preserved the memories of the odors they were exposed to early in life. Multi-site extracellular recordings in vivo from multiple regions in pre-juvenile mice revealed that the neonatal odor exposure led to a long-lasting increase of oscillatory coupling and neuronal activity in entorhinal-hippocampal networks. Moreover, the early olfactory experience enhanced the spatial working memory and associative learning later in life. These results suggest that olfactory information during early postnatal development is a critical booster for the functional maturation of learning and memory abilities and the underlying cortical circuits.