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PGAD AND THE BRAIN The Genito-Cerebral (Mental) Pathway
Agnes Kocsis Imperial Academic Health Sciences Centre, London, [email protected]
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: [email protected]
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: [email protected]
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: [email protected]
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)