Pain has many varieties, and is notoriously difficult to describe, but in recent years researchers have made some progress in trying to measure it. A story in the New Yorker this summer by Nicola Twilley, “The Neuroscience of Pain,” describes the quest “to capture the experience in quantifiable, objective data,” especially imaging data.
Twilley details the research life of Irene Tracey at University of Oxford, including tools in her lab’s “pain room”: “All of them have been designed with the aim of reliably producing in laboratory conditions sensations that hurt enough to mirror real life but don’t cause lasting harm, which would be unethical. A scientist hoping to gather publishable data can’t just hit someone with a hammer and hope that each blow is as hard as the last one, even if an institutional ethics committee would permit such a thing.”
Tracey wrote a piece for us for Cerebrum in December 2016, “Finding the Hurt in Pain,” reviewing what we know so far about pain, including how mood affects it, the role of placebos, and potential neuroethical issues. One big change in recent decades is how we consider chronic pain, she writes:
We’ve stopped thinking about chronic pain as a continuation of what caused the initial, perhaps acute, pain. Chronic pain is a whole new state, with its own underpinning mechanisms that can be shared across many different types of chronic pain despite completely different initiating causes (e.g., symptoms are similar whether it is painful diabetic neuropathy and neuropathic pain states caused by traumatic nerve injury or having chemotherapy – and this means that the underpinning mechanisms must be similar, too)—almost considering chronic pain now as a disease in its own right. This new way of thinking has given us insight into a new biology with new mechanisms to target, making the future very bright for chronic-pain sufferers.
After we published the article, Tracey had a wide-ranging chat with Cerebrum editor Bill Glovin (podcast, transcript) about her research, the field of pain in general, and the scientific life, including non-scientists’ reactions when she tells them she works on pain:
The fact that it’s such a subjective, private experience. It’s something that’s just really hard to know and understand, and it has all these societal influences of biases in culture. It’s, of course, got this great clinical need, but suddenly, when you unpack it, you realize there’s an awful lot to it. I think, then, people quite quickly realize, “Yeah, actually, that makes total sense, why you’d want to, as a neuroscientist, particularly using these non-invasive techniques, direct all your energy and attention to that,” because it allows you to really answer some very fundamental questions about the brain and how it works, and perceptions and what we mean by perception, but also understand a very fundamental experience that we all share.
I think people should remember that the central nervous system is very rapidly developing from a baby through to infant years and adolescence through to adulthood. Your life journey and all the bumps and scrapes that you’ve had on that journey, and the different experiences you have both psychologically and physically and culturally, will all influence how your central nervous system has been wired up. Increasingly, we think this is really quite important, now, for what it explains.
One area that deserves a rethink, Tracey says in the article and on the podcast, is how we consider the placebo effect:
What’s interesting about it, and what I tried to touch on in the article, is, actually, the almost irony of how we use the word placebo and what it means. I think what the science has taught us, particularly neuroimaging in the past decade and a range of different experiments, is what the physical basis of placebo analgesia is. …
It’s the network that we use when we distract ourselves from pain. They’re very old networks centered in the brain stem. We use it a lot when we’re maybe watching a very gripping movie, or are very distracted on the sports field and we don’t feel the pain of the injury. Then afterwards, when that hierarchal situation is over, you suddenly realize, “Oh my goodness. I’ve been cut and it’s really sore,” and you feel that pain, but you’ve blocked it at the time.
Quite a few of us are really quite keen to reframe placebo, because the word placebo comes from the Latin. The word that placebo chants in Latin was used by monks who were hired and paid money to come and mourn at your funeral if you didn’t have any friends. The very word and what it means and what it signifies is fake and fakery. You have this whole problem around the use of the word and people’s impression of what the word means; that they equate, if you had a placebo effect, well, then you didn’t really have the thing in the first place, so you were faking it. That couldn’t be more wrong.
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– Nicky Penttila