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This post is a review of How To Change A Memory: One Neuroscientist’s Quest To Alter The Past. By Steve Ramirez. Princeton University Press. 238 pp. $29.95.
“Canst thou not minister to a mind diseased,” Macbeth prayed. “Pluck from the memory a rooted sorrow /Raze out the written troubles of the brain /And with some sweet oblivious antidote /Cleanse the stuffed bosom of that perilous stuff /Which weighs upon the heart?”
During the last 30 years, Steve Ramirez indicates, neuroscientists have brought that wish closer to a reality. We now understand how and where our brains receive, store, and retrieve memories. Through a process called optogenetics, scientists use pulses of light with millisecond resolution to control neural activity in mammalian cells, edit memories and even create them from scratch.
In How To Change A Memory, Ramirez, a professor of psychological and brain sciences at Boston University, provides an informative and accessible account of an emerging field that has the potential to assist people afflicted with anxiety, PTSD, and dementia. Ramirez sets these developments in an up-close and personal context by revisiting memories of his parents, who immigrated to the United States from El Salvador before he was born; the prejudice they – and he –faced; the bombing at the 2013 Boston Marathon, where he narrowly escaped death; Xu Liu, his lab partner, co-author on breakthrough research, and dear friend; and his own struggles with alcoholism.
Our brains, Ramirez reveals, braid together “episodic” memories of events and “emotional” memories of the feelings associated with them. By targeting multiple brain areas, including the cortex, hippocampus, and amygdala, neuroscientists can now disentangle, activate, alter or erase them (a la the movie, Internal Sunshine of the Spotless Mind).
That said, the older the memory, the harder it is to extinguish. And many scientists believe that memories are never completely gone. Optogenetic teams have recently “hotwired back to life” memories mice formed in infancy that were deemed lost forever.
Each time we retrieve a memory, moreover, we update it. Counterintuitively, then, Ramirez points out, “the memories that are most real, the most accurate, are the ones we never recall.”
Because dreams are “the most free-form states” brains can be in, they “may act as training facilities” in which memories “offer new solutions for problems that haven’t yet happened.” In one study, psychologists discovered that people were twice as likely to solve a complex math-related task if they slept shortly after it was given to them.
Ramirez reminds us that all of us have false memories. Many Americans describe with certainty, for example, how they watched the first and second planes hitting the World Trade Center on television on September 11, 2001, even though that footage was not available until the next day. And false eyewitness testimony has led to the wrongful convictions of thousands of defendants.
Acknowledging that the visual cortex can distinguish between true and false memories, Ramirez indicates that “the sensory signature” that correctly identifies them appears not to be available to conscious awareness. He then describes how optogeneticists, using a procedure that resembles Dr. Stelline’s treatment of K in the film Blade Runner 2049, induced rodents to “think about the memory they want to see” modulated it in numerous brain areas, and activated it.
In one remarkable experiment, researchers stimulated brain cells to produce innately rewarding physiological experiences while simultaneously activating cells evoking orange-scented smells. The rodents subsequently showed a strong preference for the smell of oranges, even though they had never previously experienced it. The result also worked in reverse, with the subjects associating fear with orange-scented smells.
Ramirez recognizes that “the idea of artificially changing our memories might elicit uneasy feelings of a dystopic future where relationships are erased and governmental powers implant thoughts in our heads to mind control society.” And that designing plans to prevent the technique from getting into the wrong hands is easy to advocate, but “a lot harder to execute.”
Nonetheless, and perhaps surprisingly, Ramirez seems optimistic that “maintaining a scientifically literate electorate” which understands how the brain works, and enforcing strict regulations on how treatments are administered, will lead to “responsible policy-making, from the courtroom to the clinic” and a future in which memory manipulation “is used for the betterment of humanity.”
He may be right. But if memory serves me correctly, when there has been good reason to be deeply concerned about the future, hope and optimism have rarely been sufficient to motivate and mobilize us.
