Doctor Daniel Pine explains that in rodents, humans, and other primates, the amygdala mediates the stress response. The prefrontal cortex (PFC) is also important.
Well, so, there is a lot of research based on these ideas that mammals have similar functioning brains in terms of how those brains cope with danger, and there is a lot of research that outlines some of those similarities. There are certain parts of the brain that function highly similarly under states of threat in rodents and nonhuman primates and people, and there are other parts of the brain that do not function quite so similarly. One of the parts of the brain where there has been a great deal of interest is the part of the brain called the amygdala, and the amygdala is a part of the brain that actually tends to show a fair amount of similarity among people, rodents, and nonhuman primates.
For example, when all of these different kinds of animals learn about things that are dangerous, the amygdala is very crucially involved. We know when healthy people or healthy rodents or healthy nonhuman primates learn that something that used to be safe is now dangerous or something is capable of provoking anxiety. We know that in all of those species that there are similarities in terms of how this brain structure – the amygdala – works.
We also know that in terms of individual differences – why one rodent is more anxious than another – that there are also relationships between how the amygdala works and the levels of anxiety that a rodent might exhibit and we see similar things in people. People who tend to get anxious very frequently have subtle differences in terms of how their amygdala functions relative to people who do not get anxious so frequently. So that is an area of great cross-species similarity.
There are other parts of the brain such as the prefrontal cortex that show less similarities cross species. So in people, for example, the prefrontal cortex is particularly complex and so we know less about the precise role that the prefrontal cortex plays in anxiety, but the thought is to understand what are the unique aspects of problems and anxiety in people we are going to need to understand a lot about how that part of the brain – the prefrontal cortex – works and how it interacts with this other part of the brain – the amygdala.