Steve Ramirez: Erasing fear memories

Altering the brain's recollections may lead to treatments for depression, PTSD

Steve Ramirez

Harvard neuroscientist Steve Ramirez is studying how the brain forms memories.

Joshua Saranana

Steve Ramirez, 27
Harvard | Neuroscience
Graduate school: MIT

If not for a broken piece of lab equipment and a college crush, Steve Ramirez might never have gone into neuroscience. As an undergraduate at Boston University his interests were all over the place: He was taking a humanities course and classes in philosophy and biochemistry while working several hours a week in a biology lab. When the lab’s centrifuge, a device that spins liquids, broke, Ramirez had to use one in another lab.

“I was trying to make small talk with this girl who was using the centrifuge, ‘What’s your major?’ kind of thing,” Ramirez recalls. Hearing of his myriad interests, the student suggested that Ramirez talk with neuroscientist Paul Lipton. That led to a conversation with Howard Eichenbaum, a leading memory researcher.

The red cells in this mouse hippocampus were genetically manipulated to turn on with brief pulses of light. They store a false fear memory. S. Ramirez et al/Science 2013, Reprinted with permission from AAAS

While Steve Ramirez explains his research, artist Asher Jay sketches it. 
National Geographic

Eichenbaum told him that everything Ramirez was interested in was about the brain. “Everything from the pyramids to putting a man on the moon, it’s all the product of the human brain, which is kind of crazy when you think about it,” Ramirez says.

Studying “the most interdisciplinary organ in existence,” as Ramirez calls it, was a natural fit. While working in Eichenbaum’s lab, Ramirez got turned on to how the brain forms memories. Those explorations led to a Ph.D. program at MIT in the lab of Nobel laureate Susumu Tonegawa, where Ramirez focused on the individual brain cells that hold specific memories.

In a seminal experiment, Ramirez, Xu Liu and colleagues manipulated the memories of mice. The researchers first engineered the mice so their memory-forming cells would respond to light. Then the mice spent time in a box where they experienced a mild electric shock. When the mice were moved to an ordinary box, the researchers stimulated their memory cells with a laser, activating the memory of the shock; the mice froze in fear in the harmless box.

The work marks an important first step toward being able to manipulate memories in people — for example, erasing the fearful memories that are the fabric of post-traumatic stress disorder and other maladies. For now, Ramirez, who recently defended his Ph.D. thesis and is a fellow at Harvard, is focused on figuring out where in the Boston area he’ll be setting up his own lab.

Wherever he lands, teaching will be a central part of his work. “The word ‘professor’ comes from ‘declare publicly,’ ” he says. “We should see it as a privilege to be in the ranks of those who get to declare their work publicly.”

Ramirez is passionate about openness and collaboration in research, too. “People are too guarded with their work,” he says. “Science is about standing on each other’s shoulders.”

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