UNASSIGNED: The return of learned fear is an important issue in @entity148 research since an analogous process may contribute to long-term fear maintenance or clinical relapse. A number of studies demonstrate that mPFC and hippocampus are important in the modulation of post-extinction re-expression of fear memory. However, the region-specific role of these structures in the fear return evoked by a sub-threshold conditioning (SC) is not known. In the present experiments, we first examined specific roles of the prelimbic cortex (PL), the @entity27202 ( @entity27202 , the dorsal @entity1249 area in particular), the ventral hippocampus (the ventral dentate gyrus (vDG) and the ventral @entity1249 area in particular) in this fear return process. Then we examined the role of connections between PL and vCA1 with this behavioral approach. @entity35 were subjected to five @entity1457 (1.0-mA shock) to induce conditioned fear (freezing), followed by three fear extinction sessions (25 tone-alone trials each session). After a post-test for extinction memory, some @entity35 were retrained with the SC procedure to reinstate tone-evoked freezing. @entity35 groups were injected with low doses of the GABAA agonist @entity6341 to selectively inactivate PL, @entity27202 , vDG, or vCA1 120min before the fear return test. A disconnection paradigm with ipsilateral or contralateral @entity6341 injection of the PL and the vCA1 was used to examine the role of this pathway in the fear return. We found that transient inactivation of these areas significantly @entity73 (freezing): inactivation of the prelimbic cortex blocked SC-evoked fear return in particular but did not influence fear expression in general; inactivation of the @entity27202 area @entity73 , but had no effect on the extinction retrieval process; both ventral DG and ventral @entity1249 are required for the return of extinguished fear whereas only ventral DG is required for the extinction retrieval. These findings suggest that PL, @entity27202 , vDG, and vCA1 all contribute to the fear return and connections between PL and vCA1 may be involved in the modulation of this process.

Region-specific roles of the prelimbic cortex, the dorsal @entity1249 , the ventral DG and ventral @entity1249 of the hippocampus in the fear return evoked by a sub-conditioning procedure in XXXX .

@entity6341 :: ('MESH:D009118', 'Chemical') :: ['muscimol'] @entity1249 :: ('310218(Tax:10116)', 'Gene') :: ['CA1'] @entity1457 :: ('MESH:D012769', 'Disease') :: ['tone-shock pairings'] @entity73 :: ('MESH:D003072', 'Disease') :: ['impaired fear return'] @entity27202 :: ('MESH:C538109', 'Disease') :: ['dorsal hippocampus', 'DH'] @entity148 :: ('MESH:D001008', 'Disease') :: ['anxiety disorder'] @entity35 :: ('10116', 'Species') :: ['Rat', 'Rats', 'rats']
@entity35 :: (10116,Species) :: ['rats']
