Neuronal and behavioural pain processing

Maikowski, Lea Friederike (2018): Neuronal and behavioural pain processing: a comparison between a strong brand and a generic medication placebo using the example of Aspirin vs. 1A Pharma. Dissertation, LMU München: Medizinische Fakultät

Abstract

In our study “Neuronal and Behavioural Pain Processing: A Comparison Between a Strong Brand and a Generic Medication Placebo using the Example of Aspirin vs. 1A Pharma”, we investigated the expectation effects associated with brands by labelling two different placebo interventions. We tested the hypothesis, whether a strong brand can influence the impact of an inert substance. We studied the potential differences between the two placebos on a behavioural and neural level inducing the stimulus with noxious heat pain using Medoc. The research objective was to unveil, whether recipients can be influenced through expectations, verbal suggestions and the brand itself. We applied a two by two design with two identical placebo interventions that differed in their labelling. One group was told that they will receive 500 mg of “Aspirin” (original brand), while the other group was told that they will receive a popular ASA generic (“1A Pharma”). At the beginning, we established the individual pain levels of each subject with the numeric rating scale. Then we measured pain intensities before and after the intervention. The intervention was the administration of the placebo. We investigated behavioural as well as neural differences and looked for corresponding activated brain regions using functional magnetic resonance imaging (fMRI). Those participants, who were administered the original brand in the placebo intervention, showed a decrease in pain intensity. The generic group did not show any significant pain decrease. At the neuronal level, during the native condition, we observed activations of the anterior insula in both groups. After the intervention, the participants showed activations of the dorsomedial prefrontal cortex. The direct comparison of the two placebo conditions – the branded placebo vs. the generic – showed higher activations for the bilateral dorsolateral and dorsomedial prefrontal cortex. During the anticipation phase we observed activations of hippocampal, parahippocampal and adjacent brain areas for the generic group, only. These results suggest that only the original brand appears to evoke a behavioural response measured in terms of pain reduction. On a neuronal level, the activations were significant for the original brand only. Comparing the two placebo interventions, expectations seem to be significantly enhanced by the trusted brand, which appears to boost the placebo effect. Our results suggest that the underlying neural mechanisms of this placebo response are based on fronto-cortical neural networks.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften ; 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• Fakultäten: Medizinische Fakultät
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 18. Januar 2018
• 1. Bericht­erstatter:in: Meißner, Karin