Wednesday, November 17, 2010

2010 Conference sessions are all over - time to hug old friends goodbye

Just went to my last poster of the conference - saw a poster that just showed how the placebo effect can be related to how empathic a person is.  If they are empathic (as shown with a 10 minute questionnaire) their brains are also correlated to this empathy using a N2/Ps ratio.

I think that I want to start using this questionnaire in our studies!


Program#/Poster#:896.5/FFF22
Title:Empathy modulates the neural correlates of placebo analgesia: A laser evoked potential (LEP) study
Location:Halls B-H
Presentation Time:Wednesday, Nov 17, 2010, 1:00 PM - 2:00 PM
Authors:*B. CHAKRABARTI1,2, E. VALENTINI3,4, S. M. AGLIOTI4;
1Univ. of Reading, Reading, United Kingdom; 2Psychiatry, Univ. of Cambridge, Cambridge, United Kingdom; 3Univ. Col. London, London, United Kingdom; 4Psychology, Univ. of Rome La Sapienza, Rome, Italy
Abstract:INTRODUCTION:
The placebo response is strongly influenced by the social context (1). Empathy (defined as the ability to understand another person's emotions and respond appropriately to them) is a personality trait that exists as a continuum in the general population, and predicts individual sensitivity to the social context. Here, we sought to test the role of individual differences in trait empathy (measured using the Empathy Quotient, EQ(2)) on placebo magnitude. To this end, we compared the effects of an inert cream (vaseline) against a topical analgesic (lidocaine) to measure the subjective and neural correlates of placebo analgesia and tested its relation with individual scores on the EQ.
METHODS:
34 participants from the general population (17 females) took part in the study. The analgesic cream was applied to the dorsal surface of one of four limbs. An identical site on the contralateral limb was used as its control (no cream). The same procedure was adopted for the inert cream on the other pair of limbs. The limb (hand/foot) and order of administration of the two creams was counterbalanced across participants. Participants were told that both creams were analgesics. Nd:YAP LEPs were recorded in 4 blocks of 30 stimuli each. Subjective (Visual Analog Scale, VAS) ratings of pain intensity and unpleasantness were collected.
RESULTS:
A main effect of treatment was observed in placebo responders, with lower LEP N2-P2 amplitude and VAS pain intensity for both the analgesic and placebo treatment limbs, compared to the respective control limbs (p<0.05). Additionally, the placebo response magnitude (measured as a ratio of the N2-P2 amplitude for the placebo control limb to that for the placebo treatment limb) showed a positive correlation with EQ (r=0.415, p= 0.015).
CONCLUSION:
People with higher empathy showed a greater placebo response, as measured using LEP. This relationship may be mediated through the mesolimbic dopaminergic circuit which plays a central role both in the placebo response (3) and in empathic behaviour in humans and animals (4). This result provides novel insights into individual differences underlying the placebo response, and has practical implications for participant sampling in future clinical trials.
REFERENCES:
1. Di Blasi Z et al. (2001) Lancet, 357, 757-62
2. Baron-Cohen S and Wheelwright S (2004) JADD,34, 163-175
3. Scott DJ et al. (2007) Neuron, 55, 325-336
4. Keverne EB (2004) Phil. Trans. R. Soc.Lond. B, 359, 1349-1358

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