PGAD AND THE BRAIN The Genito-Cerebral (Mental) Pathway

Agnes Kocsis Imperial Academic Health Sciences Centre, London, UKAgnes.kocsis@imperial.nhs.uk

Two arguments for the central role of the brain

BRAIN’S DOMINANCE OVER SENSATION

Without the brain, sensation is meaningless to us

Brain activity directly influences changes in other body parts

THE CENTRAL ROLE OF DISTRESS

Without distress, there is no diagnosis of PGAD

What the brain does to sensation -25 degree rod against neck - Told it’s HOT or COLD

Arntz and Claassens 2004 The Meaning of Pain influences its experienced intensity Pain 109 (1-2) pp 20-25Baliki MN, Geha PY, Apkarian AV (February 2009). "Parsing pain perception between nociceptive representation and magnitude estimation". J. Neurophysiol. 101 (2): 875–87. doi:10.1152/jn.91100.2008. PMID 19073802.

Interpretation of hot and cold (in insular cortex)

Can our senses reliably distinguish HOT from COLD?

Does any bias influence the amount of skin damage we expect?

86% of those told the bar was cold rated the pain as below the median, 87% of those told it was hot rated it above the median (p<.001)

Those who were told it was hot rated the potential tissue damage from the rod as significantly higher (p<.01)

Expectation changes sensation

COLD?

SWEET?

HOW TO FOOL YOUR GUESTS

RED WINE WHITE WINE

WHITE WINE WITH RED COLOURING

BUT: These expectations processed through learning e.g. Ogino Y, Nemoto H, Inui K, Saito S, Kakigi R, Goto F (May 2007). "Inner

experience of pain: imagination of pain while viewing images showing painful events forms subjective pain representation in human brain". Cereb. Cortex 17 (5): 1139–46. doi:10.1093/cercor/bhl023.PMID 16855007.

Perhaps these expectations formed in brain don’t affect the body?

They just affect the head?

Swelling associated with an example of Complex Regional Pain Syndrome (CRPS)

CRPS is characterized by burning

pain increased sensitivity to

tactile stimuli, sensations of pain in

response to normally non-painful stimuli (Birklein et al., 2000;

Wasner et al., 2003)

Visual distortion of a Iimb modulates the pain and swelling evoked byMovement G. Moseley, T. Parsons and C. Spence Department of Physiology, Anatomy & Genetics, University of Oxford, UK. 2Prince of Wales Medical Research Institute, Sydney, Australia. Crossmodal Research Laboratory, Department of Experimental Psychology, University of Oxford, UK. E-mail: lorimer.moseley@gmail.com

Limb-specific autonomic dysfunction in complex regional pain syndrome modulated by wearing prism glasses.Moseley GL., Gallace A., Di Pietro F., Spence C., Iannetti GD. PAIN 2013

Visual distortion of a Iimb modulates the pain and swelling evoked byMovement G. Moseley, T. Parsons and C. Spence Department of Physiology, Anatomy & Genetics, University of Oxford, UK. 2Prince of Wales Medical Research Institute, Sydney, Australia. 3Crossmodal Research Laboratory, Department of Experimental Psychology, University of Oxford, UK. E-mail: lorimer.moseley@gmail.com

Limb-specific autonomic dysfunction in complex regional pain syndrome modulated by wearing prism glasses.Moseley GL., Gallace A., Di Pietro F., Spence C., Iannetti GD. PAIN 2013

Visual distortion of a Iimb modulates the pain and swelling evoked byMovement G. Moseley, T. Parsons and C. Spence Department of Physiology, Anatomy & Genetics, University of Oxford, UK. 2Prince of Wales Medical Research Institute, Sydney, Australia. 3Crossmodal Research Laboratory, Department of Experimental Psychology, University of Oxford, UK. E-mail: lorimer.moseley@gmail.com

Punishment and reward pathways Cortical structures are about guiding behaviour

They help us code sensations as rewarding or punishing, to guide approach or flight

Learning means that the brain has encoded associations and these associations arise automatically – unlike verbal learning!

Our experience guides us to see what we have learnt. In extreme forms, lack of experience can prevent us being able to see what we would otherwise see (like Blakemore’s kittens)

Possible explanation

Associated with cortical somato-sensory changes

Swart CMA et al., Cortical changes in complexregional pain syndrome (CRPS), Eur J Pain (2008), doi:10.1016/j.ejpain.2008.1

1.010

Cortical reorganisation treatment effective in resolving pain

Moseley GL. Graded motor imagery is effective for long-standing complex regional pain syndrome: a randomised controlled trial. Pain 2004;108:192–8. Moseley GL, Gallace A, Spence

C. Is mirror therapy all it is cracked up to be? Current evidence and future directions. Pain 2008;138:7–10.

Sources of distress causing discordance e.g. dissociation of arousal and sex

SUBJECTIVE AROUSAL OBJECTIVE GENITAL ENGORGEMENT

A modest prediction

That women with PGAD are less likely to have experienced genital sensations in the absence of any sexual context than women who do not have PGAD

Can Anxiety, Depression, Distress increase engorgement?

ANXIETY, DEPRESSION PHYSICAL CHANGES CONDITION DISTRESS

Temperature changes mediated by perceived hand position

If patient thinks it is on other side of body when it isn’t

if patient thinks it’s an actual transfer

patient seesactual midlinetransfer

if patient doesn’t know it’s an actual midline transfer

∆°C=-0.30 ±0.15°C

∆°C=+0.28 ±0.14°C

∆°C=+0.47 ±0.14°C

∆°C=+0.07 ±0.06°C

Temperature down

Temperatureup

Temperature up No sig temp change

Limb-specific autonomic dysfunction in complex regional pain syndrome modulated by wearing prism glasses.Moseley GL., Gallace A., Di Pietro F., Spence C., Iannetti GD. PAIN 2013

So we know that feelings of burning, feelings of damage, but also actual swelling, actual temperature can vary with perception, mediated by cortical structures that link our bodily sensations with our brains particular with insular cortex which is also associated with orgasm Ortigue S, Grafton ST, Bianchi-Demicheli F (August 2007). "Correlation between insula activation and self-reported quality of orgasm in women". Neuroimage 37 (2): 551–60. doi:10.1016/j.neuroimage.2007.05.026.PMID 17601749. We can also see how these perceptions are affected by

expectations of context, such as whether a situation is sexual or not sexual. And that all these may give rise to distress.

And the point? A modest proposal

Convergence of many different

aetiologies

PGADCRPS

Pain/Distress result

PGAD

Reeducate brain top down (attention training, mindfulness)

Reduce distress Send new feedback to

brain (mirrors, photoplethysmograph)