New Research Shows How Our Brain Cells Give Rise To Our Likes And Dislikes
The amygdala is a tiny, almond-shaped brain structure that is home to our likes and dislikes. When we develop positive or negative feelings toward something, we assign it a “valence”. For example, we might assign eating a cake a positive valence and being stung by a bee a negative valence. However, little is known about how cellular activity gives rise to these valences.
A team of researchers led by MIT neuroscientist and NYSCF – Robertson Investigator Kay Tye, PhD, recently honed their focus into an area of the amygdala called the basolateral amygdala to see exactly how brain cells interact and process valence.
In the study, published in Cell Reports, researchers trained mice to associate sugary drops with one audible tone and bitter drops with another. Then, researchers played each tone and recorded how neurons in the basolateral amygdala responded. They then identified which of the neurons appeared to be key in valence encoding and measured their electrical activity along with the activity of their neighbors to map out neural circuits.
The researchers discovered that certain types of neurons are associated with different valences, and that these neurons live in their own little “neighborhoods” within the amygdala. Neurons located down the middle of the amygdala project to the nucleus accumbens and are associated with positive valence. Those located toward the top and bottom right-hand side of the amygdala project to the central amygdala and are associated with negative valence. And when the mice were given the bitter drops instead of just playing the tone associated with them (a non-conditioned negative valence), neurons located in the bottom left-hand side of the amygdala tended to project to the ventral hippocampus.
Each of these cell neighborhoods also showed different levels of neuronal activity. The neurons associated with negative valence tended to inhibit the activity of their neighbors, while those associated with positive valence tended to equally excite and inhibit their neighbors.
The intermingling between these cell groups suggests that they may influence one another, and this relationship may be manipulable. We can’t change where each cell projects, but we can change its activity. This could be an effective strategy for treating mental health disorders in which valence processing is thought to go wrong, such as anxiety disorders or addiction.