Joe Cohen on Memory Blockers

Tuesday, July 14, 2009 - 12:00

Recent headlines revealed researchers are experimenting with a drug that blocks the activity of a critical memory molecule in the brain, suggesting scientists might one day be able to help us edit our memories to erase those that are painful, or to break a bad habit or cure an addiction. To date the treatment has been used only in animals, but scientists believe it is likely to work almost identically in people. Questioning Authority checked in with Joseph Cohen, MHC's dean of studies and Class of 1929 Dr. Virginia Apgar Professor of Psychology, for his thoughts on this provocative issue.

QA: Does this memory research represent good news for us? Do you think it holds promise for improving the lives of, for example, children who've been abused or soldiers suffering from post-traumatic stress disorder (PTSD)?

JC: Neuroscientific understanding of the processes of memory has advanced at an extraordinarily rapid rate in the past two decades, spurred by the designation of the 1990s as the “decade of the brain.” We continue to learn more and more about the anatomy and biochemistry of how memories are formed in the brain, how and where they are stored, and when and how they are brought back into conscious awareness or affect behavior. Inevitably, at some point in this century, we will be able to control pharmacologically the elimination or enhancement of memories during the stages of encoding, storage, or retrieval. Some of the top researchers in the field have started companies with the purpose of developing such drugs. Fictional accounts of the manipulation of memory will become a reality. But we are at an early stage in the development and testing of these drugs, and to date no drugs tested on humans have significantly changed memory capacity in people who are not suffering from neurodegenerative diseases.

Identifying drugs that could potentially reduce the often devastating psychological effects of intrusive memories of neglect, abuse, and violence does represent good news. But while I say their use is inevitable, many health-related, social, and ethical questions should be addressed before such drugs are made available to the medical profession and the public. For example, can they be targeted to one memory or a very specific set of memories without eliminating others; will erasing the memory of an emotionally stressful relationship eliminate happy childhood memories of one’s family? Elements that comprise a single memory are distributed in different areas of the brain. Can a single drug target all of them and reduce the strength of the memory? Will there be long-term adverse effects of using such drugs on the structure and function of the brain? Who will have access to these drugs and should governments regulate access? Will the cost of such drugs further disadvantage people who cannot afford to buy them?

QA: Some of our difficult and painful memories have, in fact, helped mold our values, conscience, and personality in a positive way. Could "deleting" these memories change who we are?

JC: The potential use of such psychopharmacological agents raises complex ethical questions. Neuroethics is a fast-growing field of inquiry. But these questions are raised by many of the technologies that are being developed as a result of research in neuroscience and molecular biology, e.g., gene therapy, brain-enhancement devices like transcranial magnetic stimulation, deep brain stimulation, brain implants, and brain-computer interfaces. Memory plays a critical role in determining who we are and how we respond to life situations and relate to other people. Case studies of individuals who developed retrograde amnesia or dementia as a result of disease or traumatic brain injury provide clear evidence that such changes in function can lead to marked alterations in personality and one’s sense of identity. And memory is in part the basis of an individual’s moral conscience, so it is very possible that erasing, for example, certain memories of childhood, of early socialization, would affect a person’s moral compass.

QA: And do you think eliminating the memories of past trauma would change the maladaptive behaviors victims often develop in response to those experiences?

JC: Yes, without doubt. For people suffering from PTSD, the elimination of memories of traumatic events, the flashbacks triggered continually by stimuli encountered in their daily lives or by their own thoughts, would be enormously helpful to them. But this is not to say that some of these individuals could not currently be helped with psychotherapy designed to help trauma victims. The brain continues to be plastic, to be able to change its structure and functions even in adulthood—MHC biology professor Sue Barry’s late development of stereoscopic vision is a good example of this capacity--and successful psychotherapy, I believe, can induce the same kinds of structural changes in the brain as new drugs that reduce the salience of traumatic memories.

QA: Scientists have theorized that further research could lead to treatments to enhance the function of this brain molecule and ultimately help slow or prevent dementia and other memory problems. If this were to happen, would you be concerned that some people would then use the same treatment to give themselves a competitive edge in work or school, much in the same way some athletes use steroids?

JC: Memory-enhancing drugs would probably be used in the same way that drugs for treating attention or sleep disorders are currently used. Some people who do not have these disorders take them to boost their ability to concentrate and stay awake for long periods of time, without becoming distracted or sleep deprived. We know drugs like Adderall, Ritalin, and Provigil are used by some college students, and they have also been issued to our armed forces. But recent studies suggest that these stimulants can change how the brain functions, producing, over the long term, deficits rather than increases in cognitive capacity and heightening anxiety. In all likelihood, memory-enhancing drugs will be made available before we fully know about their potential adverse effects. But like so many psychoactive drugs, people will use them anyway, focusing on the upside of taking “smart” drugs. But will memory-enhancing drugs help us remember a mathematical proof more easily, while allowing a memory of a bad experience to continually intrude on consciousness? Forgetting is a very useful function of the brain. Yet, I can imagine, in the distant future, drug cocktails that target and boost some memories while eliminating others.

QA: According to the Society for Neuroscience, the National Institutes of Health last year spent $5.2 billion, nearly 20 percent of its total budget, on brain-related projects. Are there implications from this memory research for other brain research and could it set a precedent for manipulating other brain functions?

JC: As I’ve already mentioned, there are many technologies being used or further developed that will allow us to control our psychological states and behavior. As a society, we will need to come to grips with their implications for how we view ourselves. Ultimately, the understanding of the physical basis of personality and consciousness and the ability to control and shape the functions of our brains come into conflict with most people’s dualistic views of mind-body relations and religious beliefs. Without devaluing what it means to be human we will have to come to terms with a neuroscientific view of who we are.

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