Show me the pain

Nature Outlook: Pain is an open access supplement in the current issue of Nature. There’s a collection of 10 articles with ride ranging topics including the missing ‘smoking gun’ in genetics and chronic pain, the high cost of pain, neuropathic pain, the always controversial placebo, gender differences in pain, and a fascinating brief romp through the history of pain treatment.

A couple of clangers

It’s a mixed bag, perhaps reflecting the fact that some authors are real-deal pain researchers, while others are free-lance science writers. There are the typical clangers – “If drug developers could use this information…they could develop systemic treatments that would dampen pain signals…” and “Pain is initially recognized through peripheral sensors in the skin known as nociceptors”, but there is some good stuff amongst it all.

There is no stimulus

For me, the standout article was Imaging: Show me where it hurts – a nice tour through some current thinking on brain imaging and pain. Tim Salomons’ (featured on NOIjam before) work that has cast doubt on the pain specificity of the so-called “pain matrix” gets top billing. Together with Gian Domenico Iannetti and others, Dr Salomon has demonstrated that similar brain regions are active when individuals with congenital insensitivity to pain receive a noxious laser stimulus as compared with healthy controls.

There is good coverage of Tor Wager’s work that hints at finer grain details within patterns of brain activation that are pain specific and a brief foray into Vania Apakarian’s work on predicting chronic pain based on measures of connectivity between certain brain regions (medial prefrontal cortex and nucleus accumbens) at the onset of an episode of low back pain.

The spectre of using fMRI to objectively measure pain is raised, along with concerns over potential ethical and social issues, despite which, the article notes several companies in the US are already offering services that they claim can detect a person’s ‘pain signature’.

But it is just one short sentence that really jumps out and cuts right through so much of the discussion of pain matrices and pain signatures.

But many researchers have grave concerns. Importantly, Wager’s results don’t apply to chronic pain. “The technologies Tor and others use involve recording how the brain responds to a stimulus,” explains neuroscientist Karen Davis of the University of Toronto, Canada. “In chronic pain there’s no stimulus, so we need a different approach.” (emphasis added)

Karen Davis (also featured on NOIjam before) was the lead author of a withering response to researchers who had claimed to have found the ‘ouch zone’ in the brain, and sounds a further warning regarding the conclusions drawn from fMRI studies

“The use of the technology is getting ahead of itself, and there are enormous legal and neuroethical implications,” 

The article ends on a further cautionary note from Tor Wager

“We can confirm pain of certain kinds,” says Wager. “But you can never, even in principle, disconfirm pain — because a person’s brain might just be unique.” 

Worth your time to read the whole thing.

-Tim Cocks

 We’re hitting the road and taking our NOI courses right across this great southern land:

Gold Coast 30 September – 2 October Explain Pain and Graded Motor Imagery

Perth 15 – 17 October Explain Pain and Graded Motor Imagery

EP3 events have sold out three years running in Australia, and we are super excited to be bringing this unique format to the United States in late 2016 with Lorimer Moseley, Mark Jensen, David Butler, and few NOI surprises.

EP3 EAST Philadelphia, December 2, 3, 4 2016

EP3 WEST Seattle, December 9, 10, 11 2016

To register your interest, contact NOI USA:

p (610) 664-4465

e noius@noigroup.com

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