Week 5

Herry et al. is a notable paper in finding specific populations of neurons within the basolateral amygdala that specifically react to conditioned stimuli both in conditioning and extinction of fear memories. While it would appear that the extinction-related neurons may be inhibitory interneurons, Herry et al. attempts to discredit this by noting that the extinction cells have firing rates comparable to projection neurons. However, this is not backed up by any further attempts to identify the cell types, even ex vivo, which I feel is a significant missing point of information and weakens the paper’s findings.

As has been mentioned in a number of the other write-ups, Courtin et al., while an advancement on the concepts brought forth in Herry et al. and a source of increased specificity with regard to parvalbumin interneurons, was a muddy paper with at time unclear conclusions. Perhaps it was in the language used or the lack of flow and sectioning, but while I was able to follow the general direction of the paper for the first sections, as the paper continued, it became unclear the grand message of the research. However, I personally appreciated the particular attention given to inhibitory interneurons and their disinhibition in conditioned fear expression as opposed to Herry et al. which seemed to avoid local inhibition. Courtin et al. was able to also advance on a number of the ideas from Herry et al., namely in the use of optogenetics in the place of pharmacological manipulations.