are phase locked to vHPC inputs (Adhikari et. al., 2011) and vHPC inputs to the mPFC are engaged in dampening contextual fear after extinction (Hugues and Garcia, 2007, Sotres-Bayon et. al., 2012). Similarly, vHPC inputs to the BLA become more active during contextual fear renewal (Knapska et al., 2012; Orsini et al., 2011). The differential involvement of the vHPC in mediating increases in innate anxiety and decreases in conditioned fear suggests that it gates innate and learned emotional processing via different mechanisms. Given the substantial body of literature about the importance of vHPC for both fear expression and extinction, we were surprised to find that though the vHPC showed synchrony with the mPFC and BLA in the theta and gamma range, its LFP did not show robust safety-related changes during fear discrimination. This may be because we probed auditory fear associations in a novel context, whereas most previous work assayed vHPC involvement in learned fear paradigms involving contextual conditioning.
