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Courtney Miller

Pointing to a Cure for Bad Memories

Courtney Miller, an associate professor at Scripps Florida, was born in Oregon but grew up in the San Francisco Bay Area. Her sense of both the world and her role in it were formed when she was young.

“I’ve been an optimistic pragmatist since I was a teenager,” she said. “I’ve also known that I needed a plan to get where I wanted to go."

Her plan took her from the University of California, Santa Barbara, where she graduated with a degree in Biopsychology, to the University of California, Irvine, where she earned her Ph.D. in Neurobiology, to University of Alabama at Birmingham, where she conducted postdoctoral work in learning and memory.

By the time she finally arrived at Scripps Florida, she was still fascinated by what goes on in people's heads.

"I've always been interested in the mind and how it works," she said. "In my junior year of high school, when colleges sent out their recruiting material, I got one that listed biopsychology and I asked my chemistry teacher about it. He explained neuroscience and I said, 'That's what I want to do, got it, check that off.' I went to Santa Barbara because it was one of the only universities offering a neuroscience major to undergraduates."

In the course of her academic career, Miller has managed to shed new light on the roles memory and learning play in our lives.

Her graduate training was in the field of drug addiction, specifically the component of memory that drives relapse. A 2005 study, published by the journal Neuron, showed that when given a choice between two separate rat-sized rooms, the rodents preferred the one where they remembered getting cocaine on previous days.

The study indicated that a master regulatory pathway, triggered by a molecular switch called ERK, was turned on during the room-selection process. Moreover, the scientists found that if they blocked this pathway, the animals basically forgot about their interest in cocaine.

It was the first study to identify a molecular mechanism that blocked both retrieval and reconsolidation of any type of memory.

"Memory, aging, mental illness and addiction are tied together," she said. "They all use the same systems; they just show different changes. That's why it's so complicated, because you have all of these signaling pathways and interactions and circuits that can go wrong. We're not even close to understanding how the brain or memory works. I don't think any of us will ever be out of job in our lifetime, but we're making progress in the meantime."

Her most recent work in memory extends her findings into in a realm that verges on science fiction—and raises the possibility that certain memories can actually be erased.

While the human brain is exquisitely adept at linking seemingly random details into a cohesive memory—some good, some not so good—for recovering addicts and individuals suffering from post-traumatic stress disorder (PTSD), unwanted memories can be devastating.

Former meth addicts, for instance, report intense drug cravings triggered by associations with cigarettes, money, even gum (used to relieve dry mouth), pushing them back into the addiction they so desperately want to leave.

Her latest study, published last fall, showed that memories associated with methamphetamine abuse can be remarkably fragile. They are so fragile, in fact, that blocking a specific molecule during what is known as the maintenance phase of memory formation in the brains of mice and rats can cause the loss of the memories linked to meth abuse—with no other memories affected.

“Our memories make us who we are, but some of these memories can make life very difficult,” Miller said. “Not unlike in the movie Eternal Sunshine of the Spotless Mind, we’re looking for strategies to selectively eliminate evidence of past experiences related to drug abuse or a traumatic event. Our study shows we can do just that in mice—wipe out deeply engrained memories related to drugs without harming other memories.”

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"Memory, aging, mental illness and addiction are tied together," says Associate Professor Courtney Miller.