Neural Mechanisms of discriminative auditory fear conditioning

This project aims at elucidating the role of the different auditory input pathways to the amygdala, a crucial structure for the acquisition of auditory fear conditioning. To this end we are performing lesions to each of these pathways and testing their role in the acquisition and expression of discriminative auditory fear. Previously we had found that both input pathways are necessary for intact auditory discrimination, in the context of fear learning. Thus, although either one alone is sufficient for the acquisition of fear of a sound, neither one can establish normal discrimination between a tone that is followed by shock and one that is not. Next, we tested the role of the two pathways in the recall of discriminative fear and found that only the direct thalamic, but not the cortical, projection to the amygdala was important for normal expression of discriminative fear. Finally, we found that the same thalamic pathway was important for the recall of fear extinction, suggesting a role of this pathway in the suppression of fear of neutral or safe auditory stimuli.