People often assume that their neurons are only there to do good things. While I mostly agree, I believe there are bad neurons in our brain, like there are bad genes in our DNA that have been conserved by evolution because they have only a negligible effect on reproduction.
Here is an example of these bad neurons. In this new paper from the lab lead by Dr. Ami Cohen. He found that knocking down a small population of neurons expressing the protein dynorphin decreased depression-like behavior and prevented behavior known to promote cocaine addiction.
These neurons belongs to what we call the dark side of the brains. Neurons that produce excessive pain, anxiety, depression, dysphoria to the point that it significantly impact the subject's life. It doesn't mean that these neurons are useless, in some situations they might represent an evolutionary advantage just like a bad gene causing sickle anemia protects against malaria.
Congratulations to Ami, a remarkable postdoc in the lab who managed to publish 4 papers, get a faculty position in Israel, and even more important a new baby girl, all in one year. Bravo Ami!
PLoS One. 2014 May 9;9(5):e97216. doi: 10.1371/journal.pone.0097216. eCollection 2014.
Cohen A, Whitfield TW, Kreifeldt M, Koebel P, Kieffer BL, Contet C, George O, Koob GF.