23/02/2012. Out-thinking pain How the mind can alter pain

Transcription

1 Out-thinking pain How the mind can alter pain Pain is a complex sensory and emotional experience M. C A T H E R I N E B U S H N E L L M C G I L L U N I V E R S I T Y Some people are better able than others to control their pain Human brain imaging helps us understand how the brain makes people experience pain in different ways Many parts of the brain involved in how we feel pain and others in how we can change the way we feel pain Sensory and emotional brain regions activated by pain Pain sensation How we feel pain How we alter pain Pain emotions 1

2 Stroke patients help us understand how pain sensation is coded differently than pain emotion in brain Psychological factors modulate pain via descending modulatory pathways in the brain Emotions Attention Somatosensory cortex Pain emotion without pain sensation Ploner et al Attentional state alters pain Emotions alter pain Evidence that emotions and attention control pain in different ways No pain sensation Measuring Pain Visual Analog Scales (VAS) X Most intense pain tolerable Not at all unpleasant X Extremely unpleasant 2

3 Attention alters pain intensity Attention and emotion alter different aspects of pain Emotions alter pain unpleasantness Attention changes how pain is processed in the sensory cortex Your brain when you focus on pain Your brain when you are distracted from pain Villemure et al 2003; Villemure & Bushnell 2009 Bushnell et al Emotions alters how pain is processed in limbic cortex Bad mood + Pain Good mood + Pain Attention and emotion activate different modulatory circuitry in brain Anterior cingulate cortex Villemure & Bushnell 2009 Villemure & Bushnell J. Neurosci In many cases, attention and emotions are altered together Placebo Analgesia Pleasant music Movies Virtual reality 3

4 How is placebo effect created? Imaging placebo analgesia Placebo reduces painevoked activity in the brain. Expectation Conditioning Wager et al 2004 Science Placebo activated pain modulation circuits Dopamine Opiates Brain chemicals are involved in placebo pain relief. Wager et al 2004 Science Placebo-induced opiate and dopamine activations related to pain relief How do psychological factors affect those who love or care for someone in pain? Scott, D. J. et al. Arch Gen Psychiatry 2008;65:

5 Empathy and pain Empathy increases pain perception Watching a lovedone in pain activates emotional pain areas in brain Singer et al Loggia, Mogil, Bushnell 2008 High empathy = more pain New evidence that longterm pain affects a person s brain. Loggia, Mogil, Bushnell 2007 Frida Kahlo Chronic pain alters brain structure. Chronic pain patients have changes in brain gray matter that might reflect changes in pain modulation Tracey and Bushnell J. Pain 2008 (review) 5

6 Cortical thickness ACT Score 23/02/2012 Gray matter decreased first shown in back pain patients Similar findings with other chronic pain conditions Gray matter decreases in chronic tension-type headache Gray matter decreases in fibromyalgia Apkarian AV, et al. J Neurosci. 2004;24: Schmidt-Wilcke T, et al. Neurology. 2005;66: Kuchinad A, et al. J Neurosci. 2007;404: What are the consequences of gray matter reduction? Working memory worse for FM patients 60 I S T H E R E A R E L A T I O N S H I P B E T W E E N C H A N G E S I N G R A Y M A T T E R A N D P E R C E P T U A L A N D / O R B E H A V I O R A L M E A S U R E S? Controls FM patients ACT test for working memory during distraction Ceko et al 2010 Working memory correlates with frontal cortex thickness Can gray matter changes be reversed? Evidence is beginning to say yes. ACT score Ceko et al

7 Thicker cortex after successful treatment in back pain patients Less pain thicker cortex Seminowicz D A et al. J. Neurosci Seminowicz D A et al. J. Neurosci Life-style can affect pain and cortical thickness Take-home messages Long-term yoga practitioners have increased pain tolerance and increased gray matter Villemure, Cotton, Čeko & Bushnell, IASP 2010 Psychological state can have a profound effect on pain perception and associated brain activation. Placebo analgesia is not imaginary and involves release of opiates and dopamine in the brain. Empathy in a caregiver can have a negative effect on his/her own pain perception. Long-term pain can alter brain structure and associated cognitive function, but these changes can be reversed. A positive life style can help reduce pain and reverse changes in the brain. Contact us: Thank you for attending QUESTIONS? DR. CATHERINE BUSHNELL CIRDP info@cirpd.org PAIN BC info@painbc.ca CANADIAN PAIN COALITION office@canadianpaincoalition.ca 7