Know Thy Positive Self

Maren, S. (2014). Nature and causes of the immediate extinction deficit: A brief review. Neurobiology of Learning and Memory, 113(Supplement C), 19-24. doi: 10.1016/j.nlm.2013.10.012 Last week, one of my colleagues raised a question that I didn't aware before: the immediate extinction and delayed extinction may be different substantially. This difference is so huge that, as she said, replicate a delayed extinction paradigm with an immediate extinction one may be of great danger. So I checked the literature, and do found many studies did the comparison. In the article review part, the author mentioned 17 article, including 4 studies using human subjects and 13 studies used animals (mostly rats). Although the initial reports about the immediate extinction are very positive ( immediate extinction could "erase" fear memory) (Meyers, et al., 2006), but later studies found complicated results. There are more studies reported the immediate extinction deficit, i.e., immediate...

Dranovsky, A., & Leonardo, E. D. (2015). The power of positivity. Nature, 522, 294. doi:10.1038/522294a Ramirez, S., Liu, X., MacDonald, C. J., Moffa, A., Zhou, J., Redondo, R. L., & Tonegawa, S. (2015). Activating positive memory engrams suppresses depression-like behaviour. Nature, 522, 335. doi:10.1038/nature14514 I didn't totally understand the experiments in Ramirez et al (2015), but it reads like a lot of works had been done by the authors.  The basic idea is simple: if we re-activated the positive memory of mice that currently depressed, the positive memory will decrease the depressive behaviours. This basic idea was clearly illustrated by Dranovsky & Leonardo (2015), see below Of course, the actual experiment is more complicated, as well as the figures: The above figure is the figure 1a of Ramirez et al. (2015). So, there are 6 groups. The key manipulation is the positive experience, which was exposed the mice to a female conspecific in a ...

Friedman, A. K., Walsh, J. J., Juarez, B., Ku, S. M., Chaudhury, D., Wang, J., . . . Han, M.-H. (2014). Enhancing Depression Mechanisms in Midbrain Dopamine Neurons Achieves Homeostatic Resilience. Science, 344(6181), 313-319. doi:10.1126/science.1249240 This paper is really a good read, easy to grasp what it to says. So, basically, in a series of experiments, the authors found that activation of the ventral tegmental area (VTA) dopamine (DA) neurons will make the susceptible mice, which could be selected by social defeat stress paradigm, more resilient. The novelty of this paper lies in the fact that VTA DA neuron activities were previously found to be the positive correlated to depression-like behaviours. Backgrounds:  1) Tyrosine hydroxylase-driven green fluorescent protein (TH-GFP) transgenic mice were used in these series of experiments, because of they allow to visualize and reliably record from VTA DA neurons. 2) Mice can be distinguished to resilient and suscept...