Week 4: Yiu and Han

I really enjoyed reading these two articles; the concepts were explained simply but also had the technical language necessary for them to be a viable articles published in prestigious journals. These two had a great interplay between them, Yiu determined that excitation of specific neurons in the LA prior to fear conditioning caused these neurons to be used in memory trace of that conditioned stimulus. Han then took that information one step further and said that if those neurons are then selectively deleted, then the memory trace would be erased as well. Out of all of our past articles that we have read, these two seem to have the strongest connection between them.

In particular, Yiu’s article seems to be the most complete out of the two of them, which in part may be due to the journal it was published in. Throughout our time in class it has been emphasized that each experimental method must also test for a control, to determine that the results are not due to some other factor, and while reading this paper that was on my mind the entirety of the time. The Figures in 6D accurately portray some of the controls that were tested for, and strengthen the argument Yiu is making. However, the one point of contention I have with the article is that they stated they were not able to determine excitability in vivo, but instead had to determine it using ex vivo procedures. While their usage of arc+ procedures is an excellent way to determine excitability ex vivo, there is a window for how long this stays within each cell. So, it brings to the table weather other cells were possibly excited as well but were not seen to have arc within them, and were thus determined to not be excited, although they were in vivo. I think in order to make this article stronger, there needs to be some sort of in vivo determination of excitability in order to definitively say that certain neurons were excited at the exact moment they are referencing. Without this, there are too many possibilities of error.