So we’ve learned the amygdala orchestrates our response to threatening stimuli. And that begs the question, how exactly does it know to be “afraid?” Be sure to refer to the first post in the series for anatomical reference.
Well, it’s a matter of memory. However, there are different kinds of memory. Certainly, memory comes into play when you recall the puppy you got for Christmas twenty years ago. But, there’s a different kind of memory that prompts physical procedures, like brushing your teeth. And then there’s recalled information from previous experiences – emotional memory. And the very cool thing is, functional MRI (fMRI) actually shows different brain activity for each presentation of memory.
Now, most of our memory is managed by the hippocampus. Emotional memory is a different matter. It was originally thought that emotional memory was managed solely by the amygdala; but, along came University of California, Irvine neurobiologist James McGaugh, Ph.D. Dr. McGaugh suggests the cortex plays a huge role in emotional memory. But, it needs a dance partner – a working amygdala.
If that’s the case, according to McGaugh, fear can’t be learned in the amygdala. No, the amygdala communicates with the storage cells of the cortex and gets in on the act when it tells them to prioritize a piece of memory. So, this is a process of selectivity driven by the amygdala.
So, how can we influence the amygdala? Well, as if I had to tell you, emotional memories are super tough to alter. There are all sorts of neural pathways traveling from the amygdala to the cortex, but the highways heading the other direction are far and few between. Now, if we were cavemen and women that’d be great. But, as anxiety sufferers well know, these design dynamics present problems.
According to Dr. Joseph LeDoux, featured in the previous post, influencing emotional memory isn’t about erasing them. Rather, it’s a matter of training the amygdala to react differently when walks down memory lane occur.
Let’s say there was a gaping hole in the floor of your family room. You’ve learned to walk around it for a month now because you don’t want to take a fast trip to the basement. Obviously, your avoidance behavior is based in action.
But, in order to have accomplished this, the fear of falling into the basement signal within the amygdala had to be rerouted to direct it toward areas of the brain responsible for active behavior. As a result, the amygdala now associates the hole in the floor with action, as opposed to freezing and avoidance. And each and every time this action prevents disaster the rerouting within the amygdala becomes all the more ingrained.
Be sure to have a look at tomorrow’s post. We’ll talk about some research that suggests how fear memory can be altered. Would that be huge, or what?