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27 May 2021
43 min 9 sec
Video Overview
Rael Cahn, Maria Kozhevnikov


I will present an overview of findings on the neurophysiology of self-related processing across different meditative practices. Overall, there is a small but growing body of work demonstrating that there are neurophysiological correlates to the transformation in the experience of self through meditation practice. This will include an in-depth summary of the work my colleagues and I have done assessing the impact of long-term meditation practice in the Himalayan Yoga, Isha Yoga, and Vipassana meditation traditions on the Self Name paradigm. We found that long term meditators in all three of these traditions showed a common difference from non-meditators - a significant decrease in the involuntary P300-related responding to Self vs. Other names. Moreover, we found that the amplitude of this response (which was found to be significant in non-meditators but minimal in meditators) was inversely correlated with mindfulness scores and positively correlated with negative affect. These findings indicate that this measure of self-related processing may be a sensitive marker to the transformation of the experience of self through meditative practice of different traditions with relevance to the beneficial effects of meditation on well-being.

Speaker Bio: Rael Cahn

Dr. Rael Cahn, MD, PhD, is a psychiatrist and neuroscientist with the University of Southern California Department of Psychiatry. Dr. Cahn works clinically in the Psychiatric Emergency Room at the busy LA County-USC Hospital and does research on mindfulness and other meditative practices in association with the USC Brain and Creativity Institute. He has researched the neurophysiological changes related to engaging in meditation and mindfulness practies for the past twenty years with a primary focus on EEG and ERP outcomes. He is currently working on studies assessing the neural correlates to narrative free awareness, the neural mechanisms underlying the efficacy of mindfulness practices for mood disorders and addiction, as well as the impact of psychedelic-assisted therapy for PTSD.

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  • Hello, my name is Rael Cahn. I was speaking today about meditation and the neurophysiology of self, a psychiatrist and neuroscientist working at the Department of Psychiatry, University of Southern California and Los Angeles.
  • So to start with just a few words about the traditional Buddhist view of the self, many of the audience will probably know, maybe in more detail than I do. There are many essential teachings in Buddhism, about the self and its relative illusionary appearance for humankind. In fact, one of the many lists within Buddhism’s, like the Four Noble Truths, the eightfold path, the three marks of existence, three marks of existence, had traditionally been taught to be impermanence, selflessness, and unsatisfactoriness. So, one of the most fundamental markers of existence is that the self that we experience is essentially empty, an illusion. And that the belief in a solid and stable self actually leads to suffering, and that it’s possible to realize the emptiness of self through mindfulness meditation.
  • In the modern psychological sciences, we have come to conceptualize the self as a kind of nested hierarchy of levels. From a kind of a proto of self the moment to moment representation of the bodily state, to a core perspectival self, the kind of transient sense of perspective that’s present in the here and now which does have a kind of object subject object duality to it. And then the bodily self, the sense, actually, kind of ownership of the bodily experience and then at the kind of highest level of this other paragraph, polar narrative self narrative timeline of who I am, you know, that involves memory and a sense of, you know, identifying all these characteristics the kind of new, relationship to so it’s characterized by a bunch of beliefs about what I am and what have not.
  • And, of course, what we’ve come to realize, speaking more as a clinician, is that you know, threats to the narrative itself are a central element to the experience of stress. So, of course, if our bodily self is threatened by some physical danger we experience stress and that’s how stress evolved within the animal kingdom. But as we human beings have come to identify more and more not just with the body, but also with the narrative self, anything that threatens our sense of who we believe ourselves to be or what our sense of meanness, encompass, is also experienced as a threat and experience includes a lot of the same stress responses that are oftentimes quite inappropriate, given that there’s no actual physical danger to the body, but the body will start protecting itself and acting as if it’s in physical danger, because of this kind of hierarchy of cells being kind of mapped onto one brain.
  • And indeed, unconstrained, self-focused rumination is a very characteristic aspect of many forms of suffering, that we have different names for within psychiatry, whether they be the anxiety disorders like Generalized Anxiety Disorder, the depressive disorders like major depressive disorder, there’s oftentimes a common theme that runs through them of kind of not being able to stop thinking in self referential way. And, of course, another danger of identifying with the narrative self may very well be that it’s just a disconnection from reality. Certainly within the Buddhist teaching, one would say that and when kind of delving down into what is the narrative self really composed of and what is its meaning, using the scientific approach, it’s actually pretty hard to find something real there other than just a construction that we make real for ourselves.
  • So interestingly, enough, the use of mindfulness within a kind of secular clinical perspective, which is a marker of many of the more recently developed forms of approaches to psychotherapy. Is that by helping people to dissenter from the identification with their thinking and their sense of self related processes, we are able to help them experience a much greater sense of flexibility and well being. And so although secular mindfulness is different from mindfulness as taught within some of the different Buddhist traditions, there is this kind of overlap with the psychological process. of becoming less identified with the thinking that goes on moment to moment. And a lot of that thinking has to do with the representation or experience of a narrative self.
  • So getting into some neuroscience , what have we been doing in regards to measuring the self? And there are a lot of ideas about the self, you know, philosophically, psychologically, and of course, that translates into what neurosciences have been trying to do. In the end. Because of this very slippery construct, there are multiple levels. There’s likely no single neural substrate itself. However, there certainly does seem to be a transformation of the experience of self that people experience through different forms of human teaching and learning and practice. And certainly meditative practices are quite powerful in regards to the experience of self changing.
  • So to kind of start with some of the basic neuroscience, investigations of self, this is just a summary from a review paper about 15 years ago, when they looked at any studies that have been done using fMRI up to that point, trying to distinguish between self related processing and other related processing and finding that it’s these areas along the central midline that seem to be quite involved. from study to study, oftentimes, either the frontal or the posterior but in the midline areas and more often and it turns out that those are two of the central areas of what we now call the default mode network, the posterior cingulate cortex are precuneus in the in the posterior areas in the medial prefrontal cortex and anterior areas of the midline. And of course, there’s also the temporal parietal junction are there for a primary lobe, the three primary circuits that make up what we now called the diva mode network, so some contribution of the temporal cortex and many people have heard this name by now it’s become quite well referenced and sometimes over referenced and kind of taken to me whatever, what somebody wants it to be. But it does certainly correspond to something real about the way the brain functions in areas that are more active when we are not specifically engaged in a task than when we are they kind of are the default areas that become active when we don’t have something specifically that we’re doing and of course, they are active in in concert and different elements of the circuits are active in concert with some cat tests as well, but they especially become active when we stop kind of orienting towards a task. And what are we doing in our default state when we’re not kind of engaging in tests? A lot of what we’re doing is something we have called mind wandering. Just kind of having the mind go from here to there. And could be moving in time from past or future, imagining, planning, incorporating memories, reflecting. One of the things that’s definitely true about this baseline state of ours is that it tends to be about the self meet and so the notion that some of these areas are what has shown up across many studies over time is kind of specific to self related policies is not really unexpected. Now that we know this distinction about the default mode, network, and narrative thinking.
  • So we can kind of overview the state that the narrative self in particular does seem to be somewhat specified by the default mode network, especially some of the frontal areas. And it also turns out that the default mode network is highly implicated in one of the most frequently and strongly affected circuit sets of circuits affected by meditative practice. So the first demonstration of a kind of state and trade related effect. The default mode network was demonstrated by Chad Brewer and colleagues back in 2011. And really, looking back previous to that and then certainly prospectively, since that time, a large percentage of fMRI studies have localized some kind of significant changes related to either novice practice or beginning to practice or long term practice has something about differential engagement of the default program.
  • In particular, the tendency is that the more one becomes skilled with meditative practice, the more capacity of one’s brain shows to fluctuate. Essentially turn off and on relatively engaged disengage the default mode network, in association with something around narrative practicing and self related processing. In order to really get into the details of the self experience, and brain, we have to become a lot more fine grained than just looking at average, brain scans when people are meditating or not, and start probing into moment to moment the experience of self because there really is a fluctuating fine grained aspect of experience as anyone with meditation practice will be quite familiar with. And so approaching the brain states this in a way that allows for quite tight coupling between subjective reports of internal experience and the objective measures of the brain is really necessary. Some of these approaches related to self don’t involve meditators.
  • Of course, everyone has a sense of so anybody with these kinds of approaches kind of until NAME colleagues published a very interesting study looking at the relative amplitude of the heartbeat evoked potential, the degree to which the brain is responding to each and every heartbeat and probing into whether the amplitude of the heartbeat potential might be correlated with something around self related processes, spontaneous mental states, so they probed people intermittently as they were in an EEG and what we found was that when people reported that their meditation, just prior to the probe was knee related, so thinking about something about themselves and characteristics or some kind of thinking of themselves in that objective way like me, they were much more likely to have increased heart rate evoked potential amplitude in the medial prefrontal cortex, this frontal aspect of the default mode network, whereas in those cases when they reported a lot of eye related content to their thinking, so we’re thinking not about the future generally but their own role in the future. They know very much a perspective from the sense of themselves, looking at the world. Those reports that were higher in the high dimension compared to low attended to be associated with increased empathy department, credentials, posterior cingulate, but in general, this was kind of a confirmation. First, the default mode network, anterior and posterior aspects, essentially related to something about the experience itself related to thinking moment to moment, as well as the proposition really follows from their findings that something about the way that the brain is responding to our our internal physiology is a case the heart on a moment to moment basis is very much a part of this narrative experience of self as well. They’re not two different things being included in some way, related to each other.
  • Another aspect of looking at self related changes from Lynx group over the last 20 years they’ve been systematically looking at dramatic changes in self experience in particular, the sense that the self can be experienced as outside of providing. The first years was back in 2002, when they stimulated using electrodes, an out of body experience by stimulating the right temporoparietal junction and stimulating a number of other areas. The right side of the brain, such an experience leads towards more and more fine grained approaches towards stimulating experiences that involve some transformation of the sense of being in a body. Repeatedly what they found was this temporal parietal junction to be of importance, activity changes in association with the sense that the sense of self is no longer so much located within the body. And it’s a keynote from what they sent me: integration of bodily signals, proprioception, interoception, sensory motor, etc. It’s also one of the other notes of the default mode network.
  • So, kind of zooming in on the real focus of this talk is that the focus of studying self related processes related to meditative practice may really be of value to understanding the impact of meditation on the brain and its relationship to human values. And, and the benefits of these practices. Is that it’s also possible of course, and now, people are beginning to engage systematically with the approach of looking at the experience of self when engaged in meditative practice, or as a result of engaging in meditative practice, and in particular, looking to map the changes from the identification and experience of oneself as the kind of narrative of self to more and more selfless modes or, or modes in which the boundaries of self are are just relatively disintegrated. Most systematic and thorough growing approach to this kind of neuro phenomenological enterprise has been directed by Aviva Berkovich Ohana and colleagues in Israel. And they have, in particular, conducted a number of studies with long term meditators.
  • Essentially, probing into the transition from self experience to a minimal self experience where there’s a sense of impersonal experiencing of moment to moment sensations. However, not the disintegration of the self object boundary and then that next level to the non dual states were in or selfless states, where the observing self disappears completely inexperienced is proceeding without a subject object duality. Within some spiritual registers is called one taste, just experienced, just this. So in this enterprise they have, again made these contrasts across a few studies now, from the narrative self experience minimal experience self less experienced, to be experience and found these kinds of changes, in particular, first investigation looking at their practitioners going through these experiences while having that brain recording recorded showing that decreases in gamma activity in the anterior midline regions was interesting let me go through frontal cortex seem to be characterizing the transition from the narrow stuff to a minimal stuff and then at the same time some decreases in data activity and medial prefrontal cortical areas.
  • Again, decreases in activity and the higher frequency range in some of these midline areas and a second line of investigation the fine tuning their approach to getting at self report actually revealed that the right temporal parietal junction the same junction is known by a lot of colleagues to be very much related to the sense of being in a body embodiment was also a common locus locusts have changed brain activity in association with the contrast going from notice all the way to the Sophists experience, Association of the subject object duality replicated of 10 as well as a virtual CIO, which to an even greater extent. So this dramatic reduction of beta activity that could be localized to the temporoparietal junction area and surrounding. So another approach to looking at suffering processing is to stimulate the brain with external stimuli that are somehow self related and to compare that to stimuli that are not specifically self related and to see whether meditative practices can also specifically impact that vision of the brain’s processing of self.
  • A group in in Germany led by NAMES and colleagues found and published about five years ago, the results of a paradigm where they presented subjects own faces compared to other faces, and embedded those faces within a paradigm where they were responding to flowers with a button press the target. And then regular presentations have a kind of scrambled image. And so the faces basically both the cell face and the other face were distractors from the task of pressing the button every time a flower was shown.
  • And what they found was that in line was their hypothesis. The brain response in the P 300 time range when there’s a kind of unconscious attentional, widespread attentional attention related response for the four to 600 millisecond time range usually this amplitude was different in controls. So I think that the expected extra amplitude to the self compared to another face and it was in the meditators where essentially it was just more similar. So as you can see in the figure the meditators did have a bit larger amplitude of the P 302. XL (?) versus other but the relative difference was certainly smaller, indicating that the meditators brains somehow were not apportioning quite as much extra value or salience to the fact that it was either self versus other similar kind of paradigm I want to talk about with regards to some of the work I’ve done and currently publishing.
  • This is regarding the self named paradigm. And the self named paradigm is a paradigm that has really developed out of some initial findings. During the week when you present recordings of somebody’s own name compared to others' names, the brain seems to respond with this extra sense of importance of p 300. Amplitude is really elevated to the self relative to other names. And it turned out what became a real area of investigation is that even during sleep, the self name evokes this extra processing and it’s kind of p 300. Like extra processing, relative to other names. So it’s been used as an approach to look into things like minimally conscious states or persistent vegetative states. Certainly as you get into deeper, deeper states of sleep the difference between self and other names, brain response does diminish, but it doesn’t go all the way. And in some, even some persistently vegetative states or coma like states. There’s still a little bit of this distinction that the brain is responding with that extra processing related to the self. And of course, the self name is related to the self narrative. It’s a construct that we’ve come to associate with our sense of identity that lives in the realm of abstraction and yet to be associated as being so valuable as to have this kind of hardwired brain response even during sleep.
  • So what we did is we use that self named paradigm in the context of a oddball paradigm and long-term meditators have different practice traditions, to relative to controls, and this is work that my colleague Arnaud DeLauro, and I set up at an ashram in India, the Swami Rama sadaqa.. NAME And we have a number of collaborators, including Claire NAME, who did her thesis work, partly in association with the study that has a number of different elements. But this particular part of it, the self name element, we have not yet published and I’m presenting here the findings are one of the first times we’re just in the process of getting this published. So the full paradigm involved the presentation of a number of standard 500 hertz tones, with occasional higher pitch tones that were targets or odd balls, and then these distracting white noise sounds and the self name being played or another person’s name being played.
  • The participants recorded their own voice saying their own name versus another name. And we presented the stimuli three separate times first, while the participants were responding to the targets. And then two more times, once while they’re meditating and once while we think, and here is the response, not to the self and other names, but just to the oddball stimuli were targets in one of the active tasks conditions in blue. The amplitude of the response to the targets when the participants were counting the stimuli, they didn’t respond with a button press but internally given track and counting the number of stimuli, the amplitude was much greater than when the stimuli were presented with no conscious orientation of attention to them. And there was a well known phenomenon that the P 300 becomes much greater when you attend to something that when you ignore it, so what you can see there is that the meditative group in the dark blue compared to the light blue of the control actually have a bit larger amplitude to the target stimuli or the off stimuli during the counting condition.
  • And in the two passive conditions of thinking and meditation, the amplitude was almost zero in the meditator group, whereas the control group showed a little bit lower amplitude in the counting addition and a bit higher amplitude in the in the in the thinking of meditation conditions. And in general, this statistically significant effect is that the meditator group showed decreased reduction and decreased amplitude during those passive states to these oddball tones and statistically significant, greater capacity to kind of go between a low to a high amplitude as they went from ignoring to attending to the stimuli. And this really reflects a rather well known phenomenon now that meditation does seem to be associated with a number of markers, enhanced attentional capacities or bandwidth capacity to amplify the focus of attention in terms of its representation in the brain.
  • Really, the focus of this study was in this interesting distinction between these stimuli that were identical other than the relative selfness of them. The name stimuli which are presented as distractors and the name stimuli we can see demonstrated here are the self name in the dark traces and the other name and the light traces. And so the control group, which was about 25 shows a much larger amplitude of p 300. Responding to the self name than to the other name whereas the three meditative groups looked at together show basically the same amplitude of the other name as the controls and a no real significant increase of amplitude to the self name relative to the other name and you can see that in the scalp plots, in addition to the ERP on the left, and the difference between self and other in the meditator group, and the control group was demonstrated on the far right here. With the control showing the expected great increase of 300 amplitude to the self relative to others and the meditators not showing such an increase. And specific interest here is that this effect that we saw in the controls is reproducing something that a number of investigators have found both in waking and eating and sleeping states for many years. So really the unique thing here is that meditators don’t seem to show the normal self name effect has been published. And seems to to be true of the non meditator brain, whether awake or asleep.
  • The contrast, looking here, is that each of the meditator groups analyzed separately grew up about 20 participants in each group. Just demonstrating that this was not specific to just one or the other of the groups, but it was really true across all three groups and the meditative groups, much decreased differentiation, and the brain’s response to the self compared to other stimuli. And what these meditators name here, just to flesh out the detail here a little bit is that there’s the control group on the top going from self to other and then the self awareness. There’s the HYT, which is the Himalayan yoga tradition, one of the groups whose members actually had that particular ashram in Rishikesh. India as their kind of home base. The teacher there Swami Veda Bharati was a teacher of this tradition of Himalayan yoga. And there is some certain similarity to some of the Tibetan Buddhist practices and what they practice in this Himalayan yoga tradition.
  • The ISY group is the issue of a tradition, which is taught by a well known teacher in India, South India. And at the bottom contrast is VIP for the NAME that practitioners in the tradition of going so all three meditators group showed this commonality that there was no statistically significant difference between self and other responding, whereas there shouldn’t be was in the control group. And this is represented here in graphical format. Again, the self minus other name, Scout map for controls which was the meditators average together, and post showing here that this is a highly significant p less than oh two effect for controls. P equals point seven, no significant difference for meditators and that this difference is equally true. When looking at the groups individually, each group the p value is point nine or higher. Whereas with the exception for the three meditative groups, whereas with the controls is a highly significant decrease.
  • This is one more graphical representation, or I should say, scalp map representation of the key self versus other responding, showing that not only was that finding true across the passive states in general, but specifically, it was especially true in the meditation state. So controls in the meditation state showed this enhanced self versus other responding. In the thinking state, they also showed a self versus other response that was significant. And meditators showed no difference in either thinking or meditation states between self and other stimuli. One of the interesting implications here seems to be that for controls, attempting to meditate with which what they were doing is attending to their breath, doing basic breath meditation. It seems that attending to the breath sensitizes the brain to being even more responsive to the self stimuli, engaging in a mind wandering exercise which is in the state but again, the meditators, regardless of whether thinking or meditate, just didn’t show the distinction to their brains responding to self versus.
  • The last thing I wanted to show about this study is that this responding of the brain to the self stimuli which has been again, published as a basic finding in waking state, in non meditator groups, as well as repeatedly this finding, even during sleep, that there’s this distinction between self responding. What hasn’t yet been published prior to this is whether there’s any association with the amplitude of that self name responding in voluntary self name responding, and any particular psychological dimensions, and what we saw in probing into that question is that the amplitude of the self responding actually might be related to some interesting constructs. So both mindfulness, the greater the self named responding, the lower the mindfulness scores, and in particular, the non judging aspect of mindfulness, attending tendency to kind of judge our experience moment to moment, which is kind of maybe one of the most kind of self narrative related aspects of mindfulness is judging kind of tendencies and so, of all of the dimensions of the four dimensions of the KIMS Kentucky inventory of mindfulness skills that we used to assess mindfulness with this cohort was the non judging scale that was most highly correlated in this manner. And some measures of negative aspect also showed a positive association so the greater the involuntary kind of self name, responding, the greater the average negative emotion score on the positive effect of positive and negative effects scale, when looking at the average negative emotion was greater in those with greater self, 300 amplitudes, and also, interpersonal reactivity, reacted interpersonally reacted to stress to association more distress related to hearing about how other people are observing how other people are doing also showed greater self pay 300 amplitudes.
  • So in regards to these findings, they have some reason to believe that presenting the self name seems to be of some value in distinguishing the effects of meditation. In general, it leads to an activation of the attentional system, the P 300. That is quite hardwired. But doesn’t seem to be present, at least in a weak state. Looking at meditators and this was found across three very different groups of long term meditators. So it doesn’t seem to be specific to one particular practice style or more focused attention or more kind of engaged with mantra practice, or what have you. The self name paradigm may stimulate the self schema in a way that’s related to important domains of well being as one of the other insights from these findings. The relationship between the amplitude of that self name responding and, and it being inversely correlated with mindfulness and positively correlated with negative emotion. And overall, really, my take home point that I want to deliver for the research community is that pursuing self related neuro markers, and markers related to the relative involuntary pneus of the self constructs, as well as probing into the changes in self experience associated with engaging with meditation much activity may their understanding of the relationship between meditation and given how essentially it is related to the objects of practice. So thank you very much, and I look forward to the discussion.