How do you explain what you do to your 9 year old?
[Laughs] Ok. My 9 year old is very interested in brain science by the way, he wants to know all the parts of the brain, how things work. [laughs] Sometimes he wants to be a scientist like his dad.
We use brain imaging. So we record images from a living human brain and I study what the effects are of thoughts, feelings and emotions on the body. Especially on pain and health related outcomes.
I've been interested in years on "What does it matter what you think?"
And what's the biggest revelation you've had in your study of brain imaging, does it matter what we think?
Yes. [laughs] I think one of the revelation for me, is we do a lot of studies on placebo effects. So one of the first controlled studies of what happens when you get a fake medication and you believe it's real, especially to your brain. When I got into doing this work, I really didn't know whether placebo treatments were going to be effective at all. People are pretty reliable on how they rate pain, it's experience, it's happening to your body, I don't think it's going to work. But, it did work in the sense that getting a sham treatment relieved people's pain. Sometimes substantially. We saw a number of changes that go along with that in the brain systems that seem to encode pain and emotions and decisions around pain. So the idea of placebo treatments, just the idea of being treated and engaging in treatment can actually be effective has been one of the biggest revelations for me. Because I am naturally a skeptic, I'm always looking for evidence for when they work, how, for whom, and why.
What's the most shocking example that you have seen through out your research of the placebo effect taking place in someone?
Most of our studies are really focused on the basic mechanisms and not on improving peoples clinical conditions right now. Although the new study we are starting is aimed at that. So maybe I'll have more to say about that later on. But I think that some of the most dramatic results that we've seen in our lab is if you take a sham medication you release opioids in the brain. So the brain has its own internal pharmacy. We take morphine, or Fentanyl, or Remifentanil, or any of of those different things, Codone, Oxycodone, Hydromorphone, etc. and those drugs are external drugs that act on receptors in our brain that are intimately linked with pain relief, but also with feeling good and engaging in a positive way in life events. The reason we have those receptors is because your brain makes its own.
So the brain has its own internal pharmacy so to speak that you can engage, and the reason that that internal pharmacy exist is to translate your knowledge about where you are and what's happening to you and the bigger picture into lower level changes in your brain. Where you brain is saying, "How much pain should I be feeling now? Should it be more or should it be less? Given what I have to do and where I am". So opioids help to implement that. And so getting sham treatment skin cream, can cause endogenous opioid release.
Ok. So the brain is just sort of taking in the information of, something that is supposed to help is here, and making the decision to create or experience less pain?
Exactly, that's right. A lot of work in neuroscience has really shown and fleshed out the idea, of what you are engaging in, in terms of your life. So what does it mean to you, are you in the midst of a fight, or social standoff, are you able to focus on the pain and stew on it and heal, or do you have to do something else that's very demanding where feeling pain would be harmful or distracting to you. So based on those things, what we call environmental context, your brain has the capacity to turn up or turn down pain, sometimes quite dramatically.
Have you ever experienced that in your own life?
If you really thought about it, I think every one of use has experienced that.
[8:00 - discussion about rock climbing in the cold and body temperature changing and feeling no pain ]
[9:00 - story about saving a falling rock climber and catching a rope that burnt his hands to the bone, but feeling no pain]
...In those first moments he felt no pain. That's one of those strong examples of pain and pain processing based on what's happening in the environment.
Does that have anything to do with adrenaline or is that an urban-myth? I've heard these stories of people lifting up cars and it linking back to adrenaline in some way... is that involved or is that just an urban-legend?
Adrenaline can certainty have many effects on the body. But in this case... it's too fast. There is no way that he could release adrenaline to the blood stream, have that circulate and have some kind of effect. What's likely, if we borrow from animal neuroscience research, the brain-stem which is the most ancient part of the brain, has basic circuits that regulate your heart rate, your blood pressure, how much your blood vessels dilate, whether you feel noxious, whether you breathe when you breathe in and out and... pain. At least the pain that is coming up from your spinal cord. So there is a part of that brain-stem that sends projections back down to the spinal cord that can amplify the pain, or decrease it and sometimes very dramatically. And that may contain some of the clues of what happens with chronic pain. Because in some models, there are rodent models, they can do a partial injury and create a partial injury but create a chronic pain state in the animal. In some cases this is because that part of the brain-stem is turning pain on.
And what's the trigger for that?
Well I think that's what hard to say. But, if you look at that system and where that is in humans and what that connects to, something that we have been writing about for quite awhile now is that, that system is integrated with the higher brain centers in a prefrontal cortext and your so called reward system that have a lot to do with how you think about a situation. Where is your attention? What does the signal coming in from your body mean to you? And what else is happening in the body, what else do I need to respond to? ... So we have a lot to learn about that system, but I think for many of us, much of the time it has a lot to do with how you interpret those pain signals, and what they mean to you.
You mentioned when you were doing your rock climbing, the rock was cold but it didn't really hurt. Is that something you trained yourself to do that you found is helpful to deal with these situations you are talking about?
You know, I think we have a lot to learn about the instructions you should give yourself. But I would guess, telling yourself that something shouldn't hurt is probably the opposite of what you would like to do. Because it hurts and you are thinking "this shouldn't hurt," that means something is wrong. If something is wrong you better pay attention to that signal, stop what you are doing, and so on.
So it's exactly that and when people have injuries that lead to chronic pain, one of the ideas is that people can have this response where they are really frightened and really worried about it. the go ,"What does this mean? This means I wont be able to do the stuff I wanted to do. This means something is really wrong with my back. I'm going to be dissabled. I don't know why this is happening." What they really need is some way of making sense of that.
There are multiple different kinds of cognitive therapies that have a core element where the idea of what you have to do is accept the pain and say "ok, well this hurts, it's just pain" and it's not so important.
So stopping that spiraling
Right, stopping the spiraling. I would call it a spiral, as many people in the pain field have, of fear and avoidance. So you have something, you have an injury that hurts, you stop doing things, you stop paying attention to your brain you start avoiding things that associated with pain, things that make it hurt. Maybe there's social activities, maybe there are physical activities. Those things in their self are beneficial and you taken those things away and now you are focusing on the pain signals again more and more over time. And so the pain becomes more and more disabling.
Ok So, it seems seems like all these negative thoughts and feelings and emotions about the pain can make it much worse. Can positive feelings, or any kind of positive thoughts have the opposite effect on it.
Yeah I think that they can. So I think that one of the goals of multiple kinds of therapy that can really work for people is to kind of unwind this negative spiral of avoidance of avoiding more and more stuff. That has physical effects and it has effects on your brain. Another strategy that works with a number of mental health disorders, including chronic pain for many people, is to fulfill your life with positive things. So positive engagement in other kinds of activities.
One of the predictions of neuroscientific theories, especially the theory by this researcher named Howard Fields who is very influential, is that when you engage in these other kinds of activities your brain suppresses the pain. And on top of suppressing the pain, the pain is less important to you, because you are doing something else that you value. So you are engaging the brains natural mechanisms for turning down the pain when you engage in positive things.
Now one other thing that I think is important, if you think about this fear and avoidance on one hand versus this positive engagement in-spite of pain often on the other hand, your brain is always learning, so your brain is in many ways incredibly plastic. Chronic pain itself has many effects on the brain which are probably... harmful. I think a lot that boils down to, the kinds of things you habitually pay attention to and think become stamped in with time. So if you have a back injury and there is a lot of fear and doing things and moving, this is very natural right, but it will elicit some pain and elicit some fear and the more it happens the more your brain wires to do that more easily and do that more automatically. It also wires to attend to the pain, so over time you become hyper-vigilant to those signals. And now this doesn't mean it's your fault if you are a patient. This is a natural process, you know, the things you do become more and more automatic overtime, including thoughts. So one that that is helpful for many people is to try to unwind that and replace those thoughts with other more beneficial thoughts and replace avoidance with engagement.
I think for many people there is a legitimate fear that if they are going to do something that hurts they are going to hurt their neck or hurt their back and so on. So this is where it's helpful to have someone who is a pain expert to guide you through that and sometimes that's true. But I think many people, they may have had an injury initially where moving and doing things would have hurt there back, now there is kind of a neural memory for pain and they have to change gears. And what they have to do is say, "This can just be pain. I'm going to accept it, it's not a big deal, I'll let it do it's thing and let it go down over time." So having someone who is an authority figure who can help you make that decision, where you couldn't do that on your own, "Well my back hurts and it's really bad maybe there is something wrong with my back and it's all messed up?" Having that authority figure tell you, "No it's not in your back," that would be really helpful.
So you think it's beneficial to get this diagnosis from a doctor or an expert and they can just set their mind at ease.
Yeah that's right and you need to know. People have legitimate concerns about their pain and what it means. A lot of general practitioners or neurologists or other kinds of doctors get very little training in pain education. So I don't think this point that we are talking about is very widely appreciated in the general medical community. I think the conventional wisdom is, if something hurts just don't do it.
So it takes a lot of guts and real knowledge about what might be happening with patients, and what might be happening with an individual patient. I think this is why being a pain clinician is really and art. Because the first thing a good clinician needs to do is to be able to establish an alliance and let the patient know, "hey I take your pain seriously, I believe you, I understand that it's real pain". And then, in some cases to be able to walk this fine line and say, "Yes the pain is real and it's caused in your brain. I think that you have neural sensitization, maybe it's in your spinal cord, maybe it's in your brain. But it's probably no longer in your back so you can go ahead and start the recovery process. Ignore that pain."
So you are doing a study right now or you are about to start a study that involves a couple of clinicians and some of this kind of stuff. Tell us a little about that.
Yeah so this is a study, this is really the first brain imaging study that I know that investigates this particular kind of treatment that I've been outlining in my own words. The idea is for many people with chronic low back pain, there's nothing you can find in the spine that is plausibly causing that. So many people who experience a lot of back pain, their is nothing the MRI shows that is wrong with your spine. On the other hand, if you just scan people in the population, [many] have terrible looking spines and they have no pain at all. So there is a pretty big disconnect between what looks like pathology in the spine and an MRI scan, and what people actually feel in terms of pain and disability.
So that's sort of one starting point for studying chronic low back pain because it really does seem to be something that interact a lot with peoples psychological state, with their brain state. And it might be one of those cases, where there is avoidance learning that is happened over time, that's impacting people. Psychological treatments seem to work.
Among psychological treatments, there is a growing literature on placebo effects in chronic low back pain. So if you think about a technique like spinal steroid injection (ESI). It insurance reimbursable, it's one of the most widely performed techniques today for chronic low back pain. So thousands of people across the country are getting these, every day. At substantial cost, I think it's somewhere around the order of 80 billion dollars for chronic low back pain. But only recently, because it's a surgery, have people being saying, "Well we should probably do placebo controlled trials of this and see what happens if you get a sham injection and don't actually get the real injection. A couple of those clinical trials that have been published over the last year show that placebo seems to work just as well. So the injection doesn't beat placebo. And this true of other kind of interventions as well like arthroscopic knee surgery for example for knee osteoarthritis, vertebroplasty and several other medical treatments that are commonly used. So a lot of these surgical interventions might boil down to the placebo effect, to engaging the treatment with an expert care provider being followed over time with someone who cares about you, rather than the actual contents of the injection.[More about the study here]