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Ramirez et al. 2013 and 2015

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In the first Ramirez paper, published in 2013, scientists created false fear memories in mice through use of optogenetic stimulation of the dentate gyrus (DG) or CA3. When reading the methodology of this paper, my first thoughts were of the potential that this type of research could have once we have advance further with two photon imaging (from my understanding, DG is hard or can’t be imaged because it is too dense and also there is limited mobility). Only being able to view the neurons post-experimentation leaves room for interpretation, but being able to see the neurons associated with the fear reactivation and context in live-time would support this study even further. I also would have like the exposure to the fear conditioning and different contexts to be longer, to see if there could be more neurons involved in these processes.
The second Ramirez paper, published in 2015, took the concept of memory manipulation from the 2013 paper and explored its therapeutic implementation. Interestingly, by activating positive memories via optogenetic stimulation of DG Ramirez was able to prevent the effects of the depressive behaviors. One part of the paper I found particularly compelling was the analysis showing that activation of the positive memory prevented decreases in neurogenesis caused by stress. I thought this was a very direct way to look at the effects that activation of the positive memory had in the DG whereas the behavioral tests were less so.
Overall, I thought the papers flowed together very nicely with Ramirez et. Al 2013 setting a baseline for Ramirez et al. 2015. The papers were well-supported and thorough, with Ramirez et al. 2015 having a more direct correlation to human behavior. Future directions for Ramirez et al. 2015 include increasing the 5-day stimulation protocol to account for potential longer term effects.

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