More insular matters

Deric Bownds at Mindblog, always a font of interesting and useful neuro information, posted about a meeting he was at where A.D. Craig, who researches pain and the insular cortex which helps to process it into conscious awareness, presented his ideas on the functional difference between the left and right insulas with regard to deep breathing. Check it out. Thumbs up.

My own insula seems to light up irresistibly whenever the word "insula" appears, and is drawn to examining whatever new scrap of info might have turned up. I've written about the insula before, here and here.


Here are some articles about the insula:

1. Craig AD. Pain mechanisms: Labeled lines versus convergence in central processing. Ann Rev Neurosci. 2003;26:130.

2. Craig AD. How do you feel? Interoception: the sense of the physiological condition of the body. Nature Rev Neurosci. 2002;3:655-66.

3. Henderson LA, Gandevia SC, Macefield VG. Somatotopic organization of the processing of muscle and cutaneous pain in the left and right insula cortex: A single-trial fMRI study. Pain. 2007;128:20-30.

4. Olausson H, Lamarre Y, Backlund H, Morin C, Wallin BG, Starck G, Ekholm S, Strigo I, Worsley K, Vallbo AB, Bushnell MC. Unmyelinated tactile afferents signal touch and project to insular cortex. Nature Neurosci. 2002;5:900–904.

5. Blakeslee S, A Small Part of the Brain, and its Profound Effects

Right Front Insula

I am about to read Sandra Blakeslee's book, The Body has a Mind of its Own for the second time.

Chapter 10, entitled "Heart of the Mandala", discusses a part of the brain I am particularly interested in because of my work as a manual therapist, the insular cortex. It registers all "incoming" from the body including interoception from organs. You could say it monitors 'business as usual' and remains alert to any fluctuations. It reads the body surface as well. It is both threat detector and interpreter. It is very important in my work to realize this region exists, that it is reading one's interventions continually, and to not trigger it the wrong way.

This region is found in other mammals, but in a rudimentary form. In primates it is much more developed, and humans alone have a level of integration nonexistent in any other animal:

From p. 186:

After reading off the internal state of the body from both the left and right insulas, the human brain - and only the human brain - performs yet another level of integration. The information from both your insulas is routed to the right frontal insula, the same region Critchley found corresponding in size and metabolic vigor to a person's empathic talent.

Your right front insula "lights up" when you feel all the quintessential human emotions - love, hate, lust, disgust, gratitude, resentment, self-confidence, embarrassment, trust, distrust, empathy, contempt, approval, disdain, pride, humiliation, truthfulness, deceit, atonement, guilt.

One's touch, one's handling conveys all manner of conscious and non-conscious intent - the best one can do is intend to be as helpful as possible.

One of the hardest challenges is describing something that has no words, something ineffable. Many years ago while writing a pamphlet describing to potential patients what to expect during a visit, I struggled to describe that elusive interface of manual treatment, that completely subjective zone where hands touch person and physical boundaries disappear for awhile. I wanted to reassure potential patients that I knew how to be helpful without being overwhelming. Finally I came up with a sentence describing my hands. I used the words "slow, light, kind, intelligent and effective". Looking back, I'm quite sure now that the feeling those terms encompass came up from my right frontal insula via the left cortical hemisphere and out through my typing fingers. In fact I'd lay odds that if an fMRI were done on me while writing, it would show that zone never shuts down - it's both my biggest impetus and harshest editor, for better or worse.

Manipulation and the Brain

This entry is a more edited version of a post I made on NOI in a discussion regarding manual therapies. I have included some references.

One of the participants asked, “If we discredit manipulation are we not at risk of undermining other manual type techniques for the same reason (myofascial, massage, mobilizations etc)???”

I answered with a prior version of this:

I don't think so. There is a layer of "brain" all around the outside of the body, a.k.a. skin, with fibres that go straight up to the insular cortex.1,2,3,4 We could consider manual therapies as altering the nervous system through THIS organ - I think all of the manual therapies you named do this anyway to a large extent, yet there is a conceptual void that needs filling; long ago manual therapies were named for the mesoderm (deep to the skin sensors) they were supposedly targeting (e.g. myofascial) or the sort of physical movement needed to perform them (e.g. massage, mobilization). These sorts of archaic designations deflect accurate therapeutic understanding from including the perspectives that patients' own unique nervous systems may have, keep our constructs off track, bias our self-image toward being PHYSICAL therapists instead of being physical THERAPISTS.

I doubt the actual therapy procedures, the physicality of them, are discreditable. These seem to be something humans evolved doing in order to help/comfort one another, cognitively consolidated action memeplexes that appear to stem from some deep ancestral well of primate social grooming. However, the constructs that attempt to explain and inform their use do nothing but describe such treatment as something we the treatment heroes "do" unto others. This perpetuates confusion, maintains invisibility/disregard of the highly variable nervous systems at the receiving end of the interactions as passive recipients, does nothing to consider or include the highly active role that nervous systems play in their own recovery by first accepting as non-threatening, then responding to, exteroceptive input.

Manual therapy ranging from skin touch only to active skin stretch to deeper pressure into underlying bones, muscles, neural tunnels, what have you, at varying speeds, should always be kept within our scope, but framed instead as varying kinds of exteroceptive input into a living perceiving system. Rather than being framed so strictly in biomechanical language, with its attendant and unavoidable misconceptions of cause and effect, the effects produced by manual therapies should be more carefully read as responses by the patient's living perceiving system. This necessitates seeing a patient's nervous system as more of a verb than a noun. This necessitates developing abilities to stay one step ahead of that nervous system, guiding it toward better behavior/output, not overtreating the mesodermal anatomy of it, or holding that foremost in our minds.

I'm all for retaining, but renaming, all forms of manual therapy interventions as a necessary part of their long overdue upgrade; new manual therapy names should include and reflect modern pain and nervous system concepts, and a sense of the interactivity of two nervous systems working together at every level to help one of them reduce pain and improve function/freedom. I would predict that as the perception of them shifted in us, the users of these therapies, the balance of usage of them would too; I think a trend more toward less intensive and slower forms would develop.

1. Unmyelinated tactile afferents signal touch and project to insular cortex; Nature Neuroscience (2003); H. Olausson, Y. Lamarre, H, Backlund, C. Morin, B.G. Wallin, G. Starck, S. Ekholm, I. Strigo, K. Worsley, Å.B. Vallbo, and M.C. Bushnell.
2. Pain Mechanisms: Labeled Lines Versus Convergence in Central Processing, Annu. Rev. Neurosci. 2003; A.D. (Bud) Craig.
3. Antero-posterior somatotopy of innocuous cooling activation focus in human dorsal posterior insular cortex, open access 2005; L.H. Hua, I.A. Strigo, L.C. Baxter, S.C. Johnson, A.D. (Bud) Craig.
4. The Integrative Action of the Autonomic Nervous System: Neurobiology of Homeostasis 2006; W. Jänig.

I see the understanding of how to treat live people as inversely proportional to the amount of force used and the speed of its delivery. I see the misunderstanding of how to treat live people as directly proportional to the amount of force used and the speed of its delivery. I guess nothing will ever be able to make me change my mind on this, ever.