Week 4: Han and Yiu

I thought both papers were pretty interesting and I appreciated how closely related they were to each other. After reading other responses I decided to read Yiu et al.’s first, and I’m glad I did as the Han’s paper seems to expand on the findings it presented. The finding in Yiu’s paper that suggests increasing excitability as well as increasing CREB function results in increased memory retention does not surprise me – as LTP and increased signaling is a basis for memory creation. I thought it was super interesting however that they identified such a small, seemingly random population within the LA – and how cells are selectively recruited based on neuronal excitability and CREB expression. I do wonder however, why some cells in this experiment (experimental manipulation notwithstanding) are expressing CREB more so than others. What governs the amount of neuronal excitability a cell can have at any given time? I did notice that Yiu pointed out that intrinsic excitability is governed by learning, however there still seems to be quite a bit of randomness that I wish could have been explained more.

The Han et al. paper seemed to take the findings presented in the Yiu et al. paper to a new level. First and foremost, I appreciated the reaffirmation of the finding that high-CREB/high excitability cells in the LA are responsible for fear memory creation. Additionally, Han et al. provided a strong argument that one could selectively ablate specific neurons by targeting ones that over-express CREB. While I think they did a pretty convincing job, I have to wonder how applicable this will be in a human or animal with a more advanced memory. After all, how completely could one destroy a fear memory if it had shaped, for example, a learning experience? Would what one learned from that terrible experience have to be ablated too for complete erasure of the memory? Or would the “lesson learned” still be etched in there somewhere with no reference as to why one learned it? Interesting further research!