The aim of this work is to study the neurobiology of olfactory fear conditioning in adult rats. First we investigated whether this learning induced plasticity in the olfactory pathways. We recorded field potentials evoked by electrical stimulation of the olfactory bulb in the amygdala and piriform cortex, before and after learning. We observed that learning was associated with an increase in synaptic transmission between the olfactory bulb and the amygdala (cortical and basolateral nuclei) and the posterior piriform cortex, suggesting a role of these structures in odor fear conditioning. Thereafter, we studied the consequences of neonatal olfactory fear conditioning on the same learning at adulthood. Early training induced a deficit in learning the task in adult rats. This deficit was correlated with a lack of activation in amygdala and posterior piriform cortex (2DG brain mapping). This study underlines the critical influence of early experiences on adult emotional memories.
