CNS 2025: Q&A with Ken Paller
What started for Ken Paller as traditional memory research in cognitive neuroscience has now turned into an integrated approach to understanding memory, sleep, and dreams. In addition to using novel tools and technologies to modify sleep, the work also connects with Indo-Tibetan Buddhist literature and principles. For the past few years, Paller, along with colleagues at his institution, Northwestern University, and at Emory University, have collaborated to bring together Buddhist monks, nuns, and teachers/translators with neuroscientists for a two-way exchange of information.
“Importantly, this is not a one-way pedagogical exercise; we also gain a lot, and we are so grateful for these enriching opportunities for Buddhism-Science dialogue,” explains Paller about the Emory-Tibet Science Initiative (collaborators/participants pictured above). “Another positive outcome is that we are now working with these monastic scholars as collaborators in the study of sleep and of advanced contemplative practices implemented during sleep.”
Paller will be describing the evolution of this work on memory, sleep, and dreaming at the upcoming CNS conference in Boston when he accepts the 2025 George A. Miller Prize. The talk will also showcase new research directions, including in sleep engineering and lucid dreaming.
I spoke with Paller about his start in cognitive neuroscience, what excites him about the field of sleep and memory, and about his lab’s efforts to pioneer sleep engineering, including the collaboration with monastic scholars.
CNS: How did you get started in cognitive neuroscience?
Paller: I got started before “cognitive neuroscience” emerged as the right name for the field. As an undergrad at UCLA, I majored in psychobiology and my first research project was in psychophysiology. Then, as a neuroscience PhD student at UCSD, I learned about memory research from Larry Squire and about cognitive electrophysiology from Steve Hillyard and Marta Kutas. At that point, I was a cognitive neuroscientist, but I didn’t realize it. I only did when I went to the Summer Institute in Cognitive Neuroscience. That realization guided the next steps in my career. I held four postdoc positions over 8 years, and in those years the conferences I attended in neuroscience and in psychology didn’t feel quite right. When CNS conferences started, it finally felt like I found my home territory.
CNS: Why did you end up studying sleep and dreaming? What drives your work in that topic?
Paller: My research has focused mostly on human memory. I still feel like a newcomer to sleep research, even though I made the transition years ago; it was more of an expansion than a transition. And now, many memory researchers acknowledge that what happens during sleep makes a difference for what people remember when they’re awake. I drifted over to sleep research to understand memory. Then I stayed for the fun of it.
Certainly dreams are fascinating. And the study of sleep gives us novel perspectives on consciousness. I think we also really need to figure out what it means to get high-quality sleep, and why that is essential for memory and for mental health — not just number of minutes in this or that sleep stage, but the optimal sleep physiology and the optimal overnight mental activity. There are new opportunities to modify sleep and thereby benefit not just memory but also psychological well-being.
CNS: What have you found most fascinating about sleep and dreaming?
Paller: I think the new opportunities for expanding what we call “sleep engineering” are amazing. The idea is that we can potentially make better use of sleep. Advances in wearable tech will be very helpful too. The old-fashioned thinking was that you can prepare for sleep in advance, but then once your head hits the pillow, all you can do is hope that good sleep will follow. You can try sleep pharmaceuticals, but you can’t get optimal sleep that way. So instead, we may be able to engineer better sleep.
CNS: Will you be talking about details of sleep engineering in your award talk for the CNS 2025 conference?
Paller: Yes! In short, I’ll describe how we use a combination of pre-sleep tasks and sensory stimulation during sleep. We like to present sounds, but we present them softly so that sleep is not disturbed.
Prior to 2009, there was an orthodox view among sleep researchers that sensory input is blocked at the level of the thalamus, with olfaction as the one exception. That was wrong. We now know that sensory input can be processed in the sleeping brain quite thoroughly, even low-intensity sounds. There’s another factor that limited these investigations in sleep research: something like a taboo against such studies. There was skepticism that anything interesting perceptually could happen while people were sleeping, unless they weren’t fully asleep. The evidence to the contrary, going back many decades, was usually ignored.
By 2009, when we published our first study with sounds presented during sleep, the field was finally ready to re-evaluate these ideas. Also, the claim that sleep is important for memory function, which had been controversial for many years, was finally gaining wide acceptance too.
CNS: Your abstract mentions “nudging sleep physiology”… what do you mean by that?
Paller: That’s a description of how the sounds we present alter brain activity in various ways, ranging from entraining certain rhythms to reactivating specific memories to promoting certain sorts of dreams. For example, we use Targeted Memory Reactivation (TMR) to provoke reactivation and consolidation during sleep. I also like the metaphor of “fine-tuning” sleep physiology, recognizing the idea that there are small steps that could influence sleep for the better. There is a critical role for basic research here because more work is needed to understand the physiology of optimal sleep.
CNS: I feel like people are always talking about the importance of sleep and that the benefits are becoming more widely known, but what do you think people are still missing when it comes to their understanding of sleep?
Paller: Yes, people understand that sleep is important along with exercise and eating well. Still, if there isn’t enough time to do all you need to do, you might sacrifice your sleep. If you do that, what price do you pay? The most obvious cost is sleepiness. Caffeine to the rescue? Not quite. Sleep also benefits memory, creativity, psychological well-being, and possibly the removal of toxic substances like amyloid from the brain. So even if you think you are functioning well with caffeine to help you stay alert, you might still be short-changing yourself on these other benefits.
CNS: So what can be done about that?
Paller: My lab’s newest research is exploring novel types of sleep engineering. We’re guided by continuing efforts to learn more about sleep and its benefits, but foregrounding clinical goals. Some of this may seem far-fetched, but the list includes: boosting sleep’s contribution to learning, as in motor rehab or cognitive therapies based on learning; countering maladaptive behaviors during sleep, such as some types of sleep-disordered breathing; reducing anxiety and other negative emotions that can be exacerbated during sleep; avoiding insomnia; augmenting the treatment of recurring nightmares; and helping people use their dreams intentionally. Determining which of these ideas truly have value will require scientists in many labs trying out lots of strategies. I’m very excited to see how this all develops and I’m grateful for the NIH Director’s Pioneer Award to help explore these new directions.
CNS: What do you mean by people using their dreams intentionally?
Paller: Well, there’s an established scientific literature on lucid dreaming—that’s when you recognize a dream as a dream before waking up. Lucid dreamers sometimes develop the ability to control some aspects of their dreams. This research has been very limited by the fact that it is difficult to make lucidity happen at will while recording sleep physiology. Fortunately, we’ve had some success with provoking lucid dreams using a variant on the TMR method called Targeted Lucidity Reactivation. So we’ve been able to add to this literature.
But there’s older literature on lucid dreaming too, going back 900 years: on contemplative practices in the Indo-Tibetan Buddhist tradition. We’re studying these practices in light of this literature, with the help of scholars who consider the historical and cultural context when translating ancient texts on what’s called Dream Yoga. The texts describe how lucid dreams and dream control can be used for spiritual development. Our work with people engaging in these contemplative practices aims to describe what happens, including neuroscience, microphenomenological interviews, and methods such as two-way communication between dreamers and experimenters during REM sleep.
This line of research is now converging with another endeavor I’ve taken on together with
Professor Marcia Grabowecky (we’ve been married for about as long as CNS has been around). We volunteer with a program called the Emory-Tibet Science Initiative, which was started by Professor Lobsang Tenzin Negi at Emory University [described briefly above]. My lab group and monastic scholars in India are collaborating together in this research.
CNS: What are you looking forward to doing at CNS-2025 in Boston?
Paller: Always a wonderful conference. One highlight for me will be the chance to play music with my friends in Pavlov’s Dogz, including two of my former PhD students, Joel Voss and Charan Ranganath.
-Lisa M.P. Munoz
