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Post #5 Sial and Allsop

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The first article by Sial et al, published in 2015, explores the effect in terms of depressive behaviors of forcing mice to witness a traumatic event (the abuse of another mouse by an aggressor) with a paradigm called the vicarious social defeat stress model (VSDS). After understanding this experimental set up, one thing that out to me right off the bat was how this model may or may not accurately represent PTSD as it aims to do. First of all, although witnessing a traumatic event may cause PTSD, we know that it is not guaranteed to do so. In humans I am aware that there are other factors that go into developing PTSD besides just the traumatic event itself - resulting in varying PSTD responses from person to person. Although the experiment results support the fact that witnessing a traumatic event may induce emotional stress and depressive like phenotype in mice that are similar to if the mouse were experiencing the physical pain, itself, I am left wondering if other factors played into this result. For example, was the mouse just scared of being attacked by the aggressor, themselves? How would the number of times and the severity of exposure effect their behavior? What about the age, gender, and size of the mouse? Even with these questions, considering PTSD is inherently hard to control for in mice I believe the researchers did a good job in setting up this model and showing how it relates to emotional stress in the witnessing mice. The second article by Allsop et al explores how the ACC to BLA pathway relates to observational fear learning through a series of complicated control and experimental groups. In the end, the paper supports Sial’s conclusion that emotional stress via observation in a mouse can be just as harmful as physical stress and expanded to say the ACC->BLA pathway is responsible for observational fear conditioning. I thought this study was much more complicated, in depth, and convincing. For future expansions of this study, I would be interested in seeing how other projections are affected besides just the ACC -> BLA pathway, such as the HPA axis or the hippocampus. I would also be curious to see how the age of the mouse affects the emotional and physical stress response from the traumatic event since we know that children and adults respond to traumatic events in different ways and develop PTSD in different patterns. 

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