Traditionally, dopamine is known to transmit reward signals (food, sex, etc.) in the brain and promote behaviors that lead to that reward again. What you may not know, however, is that the area of the brain that releases dopamine, the ventral midbrain, also receives signals of aversion (things we find unpleasant or even dangerous) from a far-off brain region called the lateral habenula. These avoidance signals promote behaviors that lead us to avoid unpleasant or dangerous things in the world.
These brain circuits are necessary for survival and are the focus of Dr. Garret Stuber and his laboratory at the University of North Carolina - Chapel Hill. Using a tool known as optogenetics, Dr. Stuber can excite specific populations of neurons within mouse brains and observe their effects on behavior. For example, by stimulating the neurons in the lateral habenula that signal aversion, he can cause mice to avoid the location in which they received that stimulation. He is essentially creating an aversive stimulus by stimulating the neurons that would normally respond to harmful or unpleasant cues in the world. His work has important implications in addiction and psychiatric disorders