The Memory Manipulator

On May 26, 2011, neuroscientist Steve Ramirez, then a Ph.D. student at MIT, and his colleague, the late Xu Liu, placed a mouse into a box where it had never had any negative experiences and then turned on a laser which funneled pulses of light through surgically implanted optic fibers in its neural tissue, awakening a memory of a shock it had received in a completely different box. The mouse, as the researchers hoped, froze with fear. That successful experiment was a key step forward in the field of optogenetics, or the use of pulses of light to control neural activity—in this case, to jump-start a memory.

Ramirez continues his work today as a professor of psychological and brain sciences at Boston University, and in his new book, How to Change a Memory, he details how this research could lead to advances in psychotherapy and the treatment of conditions like depression and Alzheimer’s.

What is memory?

It’s the thing that threads and unifies our identity and our sense of being. It’s our autobiographical account of the world that we can live and relive. Memory may also enable our well-being and livelihood into the future. It’s the brain’s way of accessing previous experiences so we can learn from them to enable our next steps

You call positive memories some of the most powerful biological tools available to the brain. What can memories do for us?

You can think of the worst day of your life—loss or grief or any kind of adversity—and be moved to tears within a few seconds. Or you could think of the best day you have had and be moved to borderline euphoria: You get giddy, pupils dilate, your heart rate goes up—the whole nine yards. It’s remarkable that something as seemingly simple as recalling going to soccer with my dad can alter my biology. Can we harness the magic that positive memories can do in a neuroscientifically tractable way to give us an antidote for the brain? Can positive memories be one more thing that can be used over the counter in a way that could enable well-being? Your positive memories don’t have to look anything like mine, but we share the biological capacity to have them. That’s what we want to tap into.

How does your work play into that progress?

We know through my lab’s work and others that we can artificially activate memories in rodents—access the cells that we think harbor given memories and tinker with them to turn them on and off. The goal is to see if that can be therapeutic or protective. There’s a lot of untapped potential there.

Will that be done with optogenetics?

On the order of 10 years, we’re not going to be shoving lasers in the brain. But we are going to try to inform how memory works in a therapeutic setting. Can we artificially jump-start positive memories in rodents in a way that could guide how we can do that in humans who may be unable to recall certain positive experiences or feel the benefits of those experiences? We would try to figure out ways to turn on processes that may be impaired in someone living with a certain kind of depression, maybe by adding recall of positive memories to our toolkit in a very guided way—or figuring out the conditions that have to be met in order for a positive memory to be accessed or to have beneficial effects.

Many view the human implications of turning positive and negative memories on and off as quite scary.

That scary future is something that I think about. We want to learn from history, and the instances when novel technologies were made accessible, to prevent misuse. We want to learn from the ways that our culture wasn’t really built to prevent drug abuse or addictions but was instead reactive. We want to imagine what would happen if memory manipulation was as readily accessible as a street drug, and you could just go into some alley and Total Recall your memory of a breakup. Ideally the technology would be kept in the clinic with the goal of restoring health, as opposed to something recreational, because that has red flags we’re not socially equipped to manage.

Do those fears give you pause?

The ramifications of memory manipulation are as big as it gets. But we’ve been manipulating our own memories all along, given how malleable we know they are, and so far, the fabric of our individual identity hasn’t fallen apart. So, given that, I think as long as there’s an ethically bounded goal, such as restoring health, we’re in business. If it’s for fun, we might get in trouble because we’re dealing with Pandora’s box.

What would you say to those who think we should not change or erase our memories?

I think that is said from a place of not living with a psychiatric disorder that is tethered to memories. If what someone is recalling is debilitating, then the idea of inhibiting or erasing that aspect of the past enters the conversation, especially if it’s something that’s stopping a person from living the life they want to live.

Are you hopeful that this work could lead to treatments to help prevent loss of memory in conditions like Alzheimer’s?

I hope that we can get from this work a much more concrete understanding of how something so seemingly ephemeral as memory nonetheless has a physical, measurable basis because then we can tailor treatments that become much more effective. The hope would be that, say, recalling a positive experience for 10 minutes once a day makes it 10 percent less likely that you develop some aspect of Alzheimer’s or cognitive decline. I don’t know that it’s going to be making an individual with Alzheimer’s able to recall one particular memory. But there might be treatments that make memories in general a bit more accessible, or a bit less likely to deteriorate, because we figured out some way of protecting the brain against the runaway train Alzheimer’s can be. If we can do that, I think we will have made headway into understanding how we can regain some semblance of access to memory so we can regain access to who we are.

Will we get there?

If we’re lucky. This not-knowing phase is where science exists. What brought me to this work was the appreciation that memory can become a form of guidance on how we live our lives. And if we could play the tape forward, imagine our species on its deathbed and wonder what we wish we’d done more of, I think science and research would be among those things because they would have moved that deathbed time back indefinitely.