Inside the Brain, Behind the Music is part of an ongoing series of dispatches written for the The Beautiful Brain by neuroscientist and rock musician Joseph LeDoux. Each piece presents the personal and scientific background of a song from his band The Amygdaloids‘ latest brain-themed album, Theory of My Mind (Amazon, iTunes). LeDoux and The Amygdaloids will be performing live on NPR’s Science Friday with host Ira Flatow on Friday, July 9th at 3 pm ET.
Part 3: “Glue”
On the afternoon of November 22, 1963, I was a freshman in high school sitting at my desk in Mr. Smith’s class on Business Administration. Suddenly, someone burst through the door shouting, “Kennedy was shot.” Mr. Smith switched on the classroom TV and we all sat rapt while Walter Cronkite reviewed the situation. All classroom changes were suspended, and we remained where we were the rest of the afternoon.
I remember this event as if it happened yesterday. The recollection is clear and vivid. Psychologists call this a “Flashbulb memory,” a phrase meant to highlight its clarity, as if a moment was captured by a flash of light that makes it prominent, relative to the moments before and after the flash.
So what is responsible for the flash in our head when we have a flashbulb memory? The answer, plain and simple, is emotion. Emotional arousal causes brain circuits that form memories to stamp experiences in a particularly strong way. It sort of makes sense, doesn’t it? When you are emotionally aroused, it means something important (either positive or negative) is happening in terms of your well-being. In general, you want to remember and repeat behaviors that expose you to stimuli associated with good things, and avoid doing things that might expose to bad things. One way the brain achieves this goal is by making memories of the good and bad stand out relative to the mundane and ordinary.
But saying that emotion achieves this goal is just begging the question. Fortunately, we have a good deal of information about how emotion does this. Consider the emotional arousal that occurs in negative emotions such as fear. In dangerous situations, activity is triggered in our friend the amygdala (see Part 1, Fearing). When this occurs, the amygdala sends messages through its neural output connections to a variety of areas that control different kinds of behavioral and physiological responses that help keep you safe and also help prepare you for similar future events. Particularly important in the storage of memories for future events are connections to systems that release neuromodulatory chemicals (like norepinephrine and dopamine) within the brain, and hormones (like cortisol) that travel through veins to the brain. These chemicals produce widespread activation of the brain and help keep you focused and alert, but also enhance the storage of memories. The chemicals can be thought of as neurological glue that helps makes memories stick.
Click here for the lyrics to “Glue”
Some of the songs I have written are tributes to researchers whose work I respect. My song “Glue” is a tribute to James McGaugh of the University of California at Irvine. He and his colleagues have led the way in showing how chemical modulators in the brain and hormones from the body make memories stick. The chorus in “Glue” is where the scientific facts come into this love song: “There must be something in my brain, there must be something in my veins, there must be some primal glue, that keeps my memory stuck on you.”
Before leaving this dispatch about the emotional regulation of memory, it’s important to give you an update on flashbulb memories. For many years, they were thought to be not just strong and vivid, but also especially accurate. We now know that they are not more accurate. Their strength gives you confidence in their accuracy but when emotionally based memories are checked against facts, they turn out to be no more or less accurate than non-emotional memories. So whether my vivid memories (of someone running into Mr. Smith’s classroom and shouting that JFK had been shot, of there being a TV in the class that covered the incident in real time, of Walter Kronkite being on it, and of us staying in that room rather than going to other classes) are accurate is up for grabs.
We shouldn’t put all the blame on the storage process. Inaccuracy also comes into memory during the act of remembering. It’s long been known that remembrance is a time of change, a time when new information is introduced into the memory. At some point when I remembered the events of that day, I may have filled in that I saw Walter Cronkite on the TV in the classroom because of his later coverage of JFK’s death and funeral. What’s particularly fascinating is just how much information gets added to a memory each time you retrieve it. It’s like a game of “telephone” that you play with yourself so that each time you tell a story from memory you store the memory afresh and the next time you remember the last memory rather than the original. And the more emotionally arousing, the more likely the new information will be stored and will override the previous memory for all the same reasons that emotional arousal influences the original memory that is stored. This is a particularly salient problem for eyewitness testimony–people will sometime testify about what they read in the newspaper rather than what they witnessed at the crime, since reading about the crime leads to storage of new information that ends up being part of the memory.
Memory is pretty good but it isn’t perfect. Perhaps inaccuracy is the cost of rapidly storing emotional information in an especially persistent way so that at least the general tone of important situations will be remembered vividly in the future, if not the exact details. Don’t forget (in fact, remember strongly, and accurately, if you can) that the brain is, and always will be, an imperfect device, a work in progress, one which we simply expect too much of sometimes.
Joseph LeDoux is a University Professor, Henry and Lucy Moses Professor of Science, Professor of Neural Science and Psychology and Child Psychiatry at NYU. He is also the Director of the Emotional Brain Institute at NYU and at the Nathan Kline Institute. The author of two best-selling books, The Emotional Brain and Synaptic Self, LeDoux is also a singer and song writer of The Amygdaloids, a band of scientists that plays music about mind and brain and mental disorders.