Viral-mediated expression of a constitutively active form of CREB in the dentate gyrus does not induce abnormally enduring fear memory.

Increasing CREB-dependent transcription in dentate gyrus (DG) granule cells in vivo using viral-mediated expression of a constitutively active form of CREB (CREBCA) is sufficient to enhance contextual fear memory but whether this treatment renders memory abnormally enduring is unknown. Here we confirm that over-expressing CREBCA in the DG increases retention of contextual fear conditioning (CFC) and show that this memory decays normally. Specifically, the retention scores of CREBCA mice are significantly higher than those of GFP-infected controls 24h after the conditioning, but match them after a longer exposure session and are still in the same range 48 h later. Our findings provide evidence that boosting selectively CREB activity in the DG promotes the formation of a stronger memory trace but does not increase its resistance to extinguish.