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Post 2: Tye and Chaudhury

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The two articles, Tye et al. (2012) and Chaudhury et al. (2012), both investigated how manipulating dopamine neurons using optogenetics impacts depression-related behavior, but they came to contradicting conclusions. While Chaudhury’s study discovered that increasing phasic signaling from the ventral tegmental area (VTA) increased depression-related behavior, Tye et al. found that inducing phasic signaling in the same pathway resulted in an decrease in depression-related behavior. Based on the evidence presented in the two studies, it is difficult to decide which I am more inclined to believe as I feel like both articles had flaws.

In my opinion, Chaudhury was more thorough in its methods. By breaking VTA signaling into specific projection routes, VTA to NAcc and VTA to medial prefrontal cortex (mPFC), this lead to a more comprehensive approach to the understanding the susceptibility of mice to depressive-related behavior. I would have like to have seen Tye et al. do this. It illustrated that although VTA to NAcc phasic firing resulted in increased depression-related behavior, VTA to mPFC phasic firing resulted in the opposite effect; this shows that it is important not to oversimplify the role of VTA dopamine neurons.

 That being said, I believe that being only using male mice Chaudhury limited these results from being widely accepted, as if we truly to model human behavior, we need to acknowledge that there might be sex differences. Would we expect there to be a different response to the social-defeat stress method if it was a female mouse paired with a breeder? Are breeder mice so naturally territorial that we expect them to attack a new mouse (even a female) put into their habitat every time? Do they do something to the breeder mouse to provoke aggressive behavior? Future directions include incorporating both sexes but also maybe choosing a different method chronic mild stress, such as tail-suspension test from Tye’s article.


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