Should we improve our memory with direct brain stimulation?

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By Laura Cabrera, PhD

Should we be worried about the use of direct brain stimulation to improve memory? Well, it depends. If we think of people with treatment refractory memory conditions, or those situations where drugs are not helping the patient, such an approach might seem like the next sensible step. There is reason, however, to remain skeptical that this strategy should be used to improve the memories of people who function within a normal memory spectrum.

Image description: The illustration “Light Bulb” by Alvaro Tapia is a colorful abstract depiction of the human head/brain as a light bulb. Image source: Alvaro Tapia/Flickr Creative Commons

The quest to improve memory is hardly new. Throughout time people have engaged in ways to improve their memories, such as eating particular foods, employing mnemonic strategies, or taking certain drugs, but the quest does not end there. A recent New York Times article discussed findings from a direct brain stimulation study (Ezzyat et al., 2018) on the possibility of using brain stimulation to rescue functional networks and improve memory. In that study, 25 patients undergoing intracranial monitoring as part of clinical treatment for drug-resistant epilepsy were additionally recruited with the aim of assessing temporal cortex electrical stimulation on memory-related function.

The prospect of using brain stimulation to improve memory, initially introduced in the 1950s (Bickford et al., 1958) re-emerged in 2008 when a study using hypothalamic continuous deep brain stimulation (aka open-loop DBS) to treat a patient with morbid obesity revealed an increased recollection capacity in that same patient (Hamani et al., 2008). Subsequent studies have attempted to prove that direct brain stimulation is useful for memory improvement. However, the data on open-loop deep brain stimulation currently remains inconclusive.

The approach by Ezzyat and colleagues, wherein neural activity is monitored and decoded during a memory task, suggests an improvement over open-loop approaches. In this treatment modality stimulation is delivered in response to specific neural activity, detecting those times when the brain is unlikely to encode successfully and rescuing network activity to potentially improve overall performance.

In that study stimulation was triggered to respond exclusively to those patterns of neural activity associated with poor encoding, effectively rescuing episodes of poor memory and showing a 15% improvement in subsequent recall. Indeed, those results might sound promising, but this type of memory intervention raises a number of ethical issues.

Image description: Computer memory components are shown inside a model of a human skull. Image source: © Michel Royon/Wikimedia Commons

In a very direct fashion memory is related to the core of who we are. It allows us to build an interpretation of ourselves and our environments, and in so doing gives us orientation in time as well as in our moral life. As surrealist Luis Bunuel put it, “Life without memory is no life at all … Our memory is our coherence, our reason, our feeling, even our action. Without it, we are nothing …” Equally, memory plays a crucial role in cognition, learning, and performance, and as such it is not a surprise that many people feel particularly drawn to memory improvement strategies. Yet there are salient, concerning issues when directly meddling with the human brain, including those risks associated with deep electrode insertion such as infection, hemorrhage, seizure and hardware complications. One might reasonably question whether a 15% memory improvement is worth such high stakes risks?

Another concern is the potential for undesirable – but as yet undetermined – side effects. Those uncertainties are why it seems unlikely that such an approach will be used in healthy individuals or for mild memory dysfunction cases. Still and yet, closed-loop deep brain stimulation has alternative utility. It can be used to improve understanding about the specific brain target most centrally related to certain memory functions, and then use that information to employ less invasive interventions, such as transcranial magnetic stimulation (TMS).

The sorts of studies engaged by Ezzyat’s team and others overlook the fact that memories are not just physically located within the cranial cavity. We have external technologies such as photographs, videos, and agendas to help us remember, and so one might reasonably ask if we really need invasive brain implants to achieve the same ends? The brain’s plasticity is equally overlooked, erroneously assuming that the same brain targets will bring equivalent outcomes for healthy individuals as well as for those with memory impairments. Moreover, the identified interventions improve memory encoding, but do not help with the many errors to which memory is perplexingly prone, such as misattribution, suggestibility, and bias. For healthy individuals, addressing those common memory errors could potentially be more helpful than improving encoding with brain stimulation.

In addition, certain types of memory enhancement could bring new perspectives on one’s life, and even affect the ability to understand the past and imagine the future. In fact if we truly were to remember everything we encounter in our lives we might well be overburdened with memories, unable to focus on current experiences and afflicted by persistent memories of those things that we deem unimportant.

Open-loop neural implants already bring a different configuration of human agency and moral responsibility. Closed-loop implants with their ability to both stimulate and continuously monitor neural patterns bring further issues for consideration, such as neurosecurity (e.g. brain hacking) and mental privacy. Improved connectivity of this type of implant further enables the potential for malicious interference by criminals. Concerns about mental privacy figure prominently in other neurotechnologies, which, similar to brain implants, have the ability to access neural data correlated with intentions, thoughts, and behaviors. This enhanced proximity encroaches on the core of who we are as individuals, providing access to mental life that in the past was accessible only to oneself.

Finally, the media hype in itself is problematic. The New York Times’ article mentioned that the 15% improvement observed in the Ezzayt study was a noticeable memory boost. This sort of inflated media coverage does a disservice to the good intentions and professional rigor of scientists and engineers, and misleads the reader to be either overly-optimistic or overly-worried about the reported developments.

With these many considerations in mind, it is clear that direct brain stimulation will replace neither pharmaceuticals nor less invasive memory improvement options anytime soon. Those who crave memory improvement through memory intervention technologies might best be mindful of the aforementioned ethical and social considerations.

Laura Cabrera photoLaura Cabrera, PhD, is an Assistant Professor in the Center for Ethics and Humanities in the Life Sciences and the Department of Translational Science & Molecular Medicine at Michigan State University.

Join the discussion! Your comments and responses to this commentary are welcomed. The author will respond to all comments made by Thursday, May 10, 2018. With your participation, we hope to create discussions rich with insights from diverse perspectives.

You must provide your name and email address to leave a comment. Your email address will not be made public.

More Bioethics in the News from Dr. Cabrera: Can brain scans spot criminal intent?Forgetting about fear: A neuroethics perspective

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Forgetting about fear: A neuroethics perspective

Bioethics-in-the-News-logoThis post is a part of our Bioethics in the News series. Visit this page for more information.

By Laura Cabrera, PhD

The alluring possibility of deleting memories has been the topic of movies such as Men in Black, Total Recall, and Eternal Sunshine of the Spotless Mind, yet in real life the chances of ever achieving such fine-tuned memory erasure is not a realistic bet. But suppose if by taking a pill we could forget about fear and about those things that cause us to be anxious? A New York Times article addressed exactly that possibility with the recent coverage of a drug to “cure” fear—by dampening memory. One factor influencing and shaping memory processes is their emotional intensity. Extensive psychological research and personal experiences confirm that events that occur during heightened states of emotion, such as fear, anger and joy, are generally more memorable than less dramatic occurrences. That research explains why you might remember exactly what you were doing when you found out about 9/11, but not necessarily be able to recall what you had for supper two days ago. Some memories with an intense emotional component might leave individuals susceptible to develop phobias, or possibly even post-traumatic stress disorder (PTSD).

Image description: a black and white image of an individual sitting on a bed with their hands raised and their face blurred in motion. Their mouth is open like they are screaming. Image source: Flickr user Sensus Capit.

The current standard treatment for many anxiety-related disorders involves exposure therapy. There are two distinct points at which memory is more vulnerable to modification, when we first form those memories and when we recall them. Thus, the idea behind exposure therapy is to repeatedly present the feared object or the frightening memory in a safe environment, so that the person can then acquire a new safe memory, in effect replacing the “bad” memory. However this type of therapy has concerning limitations including that the old fear could awaken with a vengeance; the therapy might be useful for only a limited period of time; and finally for some people the idea of reliving frightening memories is simply intolerable.

Given the limitations of those therapies, and considering that there might be cases where underlying organic brain profiles make people more susceptible to develop phobias and trauma, other interventions, including pharmacological ones, have been widely researched. Propranolol—a Food and Drug Administration (FDA) approved drug to treat hypertension—has been found to have potential for disrupting memory reconsolidation, in particular by influencing the affective value of a given memory. A number of preliminary empirical studies demonstrate propranolol’s efficacy in reducing PTSD symptoms when taken within a few hours of the traumatic event (Brunet et al., 2008; Pitman et al., 2002). Those studies suggest that patients with PTSD symptoms had a reduction in trauma-associated physiological responses after taking propranolol. Friedman (New York Times) mentioned yet another propranolol study (Soeter and colleagues, 2015). Those researchers found that arachnophobes (those experiencing fear of spiders) exposed to the fear trigger, i.e., a spider, to reactivate their fear, were then given propranolol and as a consequence were able to touch the spider within days. Reportedly, the behavioral effects persisted 1 year after the study.

Propranolol is just one of many agents currently being researched with the goal of facilitating the extinction of fear and trauma. Some have called this quest for drugs that would dampen “bad” memories, “therapeutic forgetting.” However, the process is not as easy as simply popping a pill to have the traumatic memories disappear. For example it remains unclear whether broader fear memories or older memories would be similarly sensitive to drug-facilitated memory dampening. There is an additional risk that by reducing the emotional intensity of memories, in a linked fashion, we might also dampen their factual richness, or inadvertently distort positive memories as well.

Discussion around the normative implications of memory modification is an especially hot topic within neuroethics. Some are disturbed by attempts to directly tamper with memory because they view it as threatening to our identities and the authenticity of our experiences. Conversely, others see it as a genuine attempt to relieve suffering. The President’s Council on Bioethics is well known for arguing against memory dampening (Bioethics, 2003), noting that “We might often be tempted to sacrifice the accuracy of our memories for the sake of easing our pain […] severing ourselves from reality and leaving our own identity behind.” But others argue that in cases of severe phobia or anxiety, memory dampening interventions can indeed be useful and in fact might help people to shape their identities in a positive way and in so doing be more authentic to what they take their lives to be.

When considering memory-erasing drug interventions there are related pragmatic considerations such as safety, informed consent, and social pressure. In relation to concerns about social pressure, some have argued that when compared with the potential costs of hours of psychotherapy and chronic treatment with pharmacological agents for anxiety and PTSD, the financial benefits of pill-induced therapeutic forgetting are unmistakable. However, this line of thinking might unreasonably push society further in the direction of a search for easy solutions for problems that might require far more than simply popping a pill.

Fear is a natural and adaptive response. Up to certain limits anxiety and fear are appropriate reflections of the fragility of human life. The disagreement with reducing the emotional intensity of memories associated with traumatic events is not so much about whether that strategy is good or bad, but instead, disagreement lies in the zone of ambiguity, “where reasonable people will reach different conclusions about the same set of facts” (Parens, 2010). Where can one reasonably draw the line between therapeutically forgetting and just “messing around” with memories? Trauma, fear and anxiety are concepts shaped as much by cultural and societal standards as by medical ones. This diversity of influence has contributed to the widening of diagnostic boundaries, which can result in people opting for taking a pill, rather than the more arduous process of reflecting on their fears and the emotional aspects of their memories. Perhaps a memory erasing pill would prevent us from engaging in experiences necessary for moral learning and personal growth. As a society, we should be careful where to set the limits of normal and pathological. Scientific breakthroughs are nearly always double-edged swords. So while the prospect of a pill for therapeutically forgetting brings hope for those suffering with debilitating phobias and trauma, we simultaneously need to keep an open and critical mind on the related expansion of disorders boundaries—and with that expansion the linked potential of exploitation by pharmaceutical companies.

cabrera-crop-2015Laura Cabrera, PhD, is an Assistant Professor in the Center for Ethics and Humanities in the Life Sciences and the Department of Translational Science & Molecular Medicine at Michigan State University.

Join the discussion! Your comments and responses to this commentary are welcomed. The author will respond to all comments made by Thursday, April 7, 2016. With your participation, we hope to create discussions rich with insights from diverse perspectives.

You must provide your name and email address to leave a comment. Your email address will not be made public.

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