Week 4 Articles

In accordance to what our class has yearned for, I enjoyed reading through the rationale that the Reznikov paper provided for weak-extinction animals to model PTSD.  Using fear conditioning to establish groups of rats unable to properly extinguish a short-termed conditioned fear response, the later deficits in long-term anxiety levels and fear responses were observed and showed that weak-extinction characterization could be a strong indicator of future behaviors.  The criterion for distinguishing weak from strong extinction was slightly rudimentary but in the context of the paper I almost give it benefit of doubt.  Additionally, Reznikov tested the converse to establish that a stressor is necessary in eliciting this symptomatic response.  This very well depicts the human experience of post-traumatic stress disorder, and adds comfort to using it as a preclinical model to be further used.  I also appreciated the approach Reznikov took to assessing corticosterone levels by collecting blood samples before any behavioral conditioning.  The results that low corticosterone levels correlate with the weak-extinction group are novel in the field.  However I don’t believe those results should be looked over without further investigation as such anomalies can come back around to reflect on a fundamental misconception.  The one downside to the study that was apparent, and noted, was the small sample sizes being used.  

The Herry paper also provided a convincing argument.  Putting fear and extinction neurons under congruent testing brought light to the fact that differentiated activity of very similar neural circuits is innervating context dependent responses.  Herry shows definitive changes in activity, but also reveals the overlap in transitioning responses.  The actual circuits were explored in detail, which was nice to read after the Reznikov paper.  Even though the experimental procedures were a little harder to follow, the flow and presentation of figures was successful in conveying their point.