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Week 2: Neurogenesis and Anti-depressant actions response

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The two articles selected this week, Santarelli et al. (2003) and Bessa et al. (2009), investigated neurogenesis in the hippocampus with administration of anti-depressants (ADs) and how it might affect the alleviation of behaviors associated with depression. Upon first glance, the articles seem to contradict each other. But with a more thorough read-through of the papers and an understanding that as time goes on, more discoveries are made within the neuroscience community. Santarelli et. al seems to be a necessary precursor to Bessa et al. in developing a deeper understanding of ADs.

In Santarelli et al., mice were subjected to a novelty-suppressed feeding task in order to study how ADs effect neurogenesis. This article discovered that disrupting the neurogenesis induced by ADs through use of radiation blocked the behavioral response to the ADs. The major finding of the paper was that the behavioral effects of ADs might be the result of stimulation of neurogenesis in the hippocampus. Bessa et al. takes this research in a different direction. It refutes the claim that neurogenesis in the hippocampus is reason for the amelioration of depressive symptoms with the use of ADs and instead takes the approach that neural plasticity is responsible for the amelioration of depressive symptoms. Bessa et al. also performs behavioral tasks on mice but with a more all-encompassing approach. This article uses a novelty-suppressed feeding task, a sucrose preference task, and a forced swimming task to assess the effects that ADs have rather than just the novelty-suppressed feeding task from Santarelli et al. paper. The takeaway from Bessa et al. was that ADs retain their therapeutic properties even with neurogenesis is blocked.

So although Bessa et al. rejects the claim that neurogenesis in the hippocampus with AD use is reason from the alleviation of behaviors associated with depression, it relies on previous research being done in this area to get to its new conclusion that neuroplasticity in the hippocampus with AD use is reason from the alleviation of behaviors associated with depression.

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