Placebo – Relief Beyond Belief
Dr. Gilles Michaux, Psychobiology, Uni. of Luxembourg
Although pain has traditionally been discussed in the framework of sensory physiology and psychology of perception, it is fundamentally different from all other sensory systems. In addition to a sensory component related to information about the location, the duration and the intensity of the noxious stimulus, pain is almost always characterized by an emotional-motivational component (i.e. suffering), which drives us to avoid or to stop it. The cognitive-evaluative component is concerned with the appraisal of the current pain by retrieving comparable situations from memory stores. Within the brain, these components have been claimed to rely on distinct neural substrates, which are however closely interconnected. Two further elements to be discussed are the autonomic component (e.g. blood pressure, heart and respiration rate), which is closely related to the emotional and the motor component (withdrawal reflexes, facial expression etc.). The described multidimensionality points out that physiological and psychological mechanisms have to be considered concomitantly for the assessment and modification of pain.
Taking into account the different dimensions of pain processing, the second part of the talk will be devoted to the presentation of psychophysiological aspects of pain modulation. The placebo effect and its dependence on sensorimotor factors like associative learning and motivational factors like treatment expectations and the desire for pain relief will be discussed. Another interesting and related issue in this field is the modification of pain by hypnosis (i.e. hypnotic anesthesia), with its ability to independently modulate perceptual (‘hurting’) and emotional (‘suffering’) aspects of the pain experience. Both phenomena will be analyzed within a neurobiological and psychosocial framework with regard to their potential to disentangle pain perception and affect.
Pain, Suffering and Hurt: A Multidimensional Psychobiological Perspective
Prof. Fernand Anton, Psychobiology, U. of Luxembourg
Although pain has traditionally been discussed in the framework of sensory physiology and psychology of perception, it is fundamentally different from all other sensory systems. In addition to a sensory component related to information about the location, the duration and the intensity of the noxious stimulus, pain is almost always characterized by an emotional-motivational component (i.e. suffering), which drives us to avoid or to stop it. The cognitive-evaluative component is concerned with the appraisal of the current pain by retrieving comparable situations from memory stores. Within the brain, these components have been claimed to rely on distinct neural substrates, which are however closely interconnected. Two further elements to be discussed are the autonomic component (e.g. blood pressure, heart and respiration rate), which is closely related to the emotional and the motor component (withdrawal reflexes, facial expression etc.). The described multidimensionality points out that physiological and psychological mechanisms have to be considered concomitantly for the assessment and modification of pain.
Taking into account the different dimensions of pain processing, the second part of the talk will be devoted to the presentation of psychophysiological aspects of pain modulation. The placebo effect and its dependence on sensorimotor factors like associative learning and motivational factors like treatment expectations and the desire for pain relief will be discussed. Another interesting and related issue in this field is the modification of pain by hypnosis (i.e. hypnotic anesthesia), with its ability to independently modulate perceptual (‘hurting’) and emotional (‘suffering’) aspects of the pain experience. Both phenomena will be analyzed within a neurobiological and psychosocial framework with regard to their potential to disentangle pain perception and affect.
In recent years, a sensorimotor view has been proposed as an alternative framework to understand perception and perceptual experience. According to the sensorimotor view, seeing or touching for example, should be studied as the skillful exercise of activities, rather than in terms of the production, by neural processes, of an end-product (an internal representation of the seen scene). One of the claimed advantages of the sensorimotor approach to perception is that it provides a fresh and liberating view of the allegedly intractable problem of consciousness, by thinking of consciousness as a way of interacting with one’s environment.
After briefly characterizing this sensorimotor approach to perception and perceptual awareness, Erik Myin will look at how it can be applied to pain. The crux, so it will be proposed, lies in looking at pain from an ‘agentive perspective’, the perspective from which a person can undertake actions, and experiences the world in terms of potential for action. Pain, so conceived, becomes an unwilled distortion of one’s agency – an unmotivated motivation. This point of view makes visible a natural link between basic physiological pain and more abstract forms of suffering (as in depression), as both are related to a reduction of an agent’s potential for action. Erik Myin will then discuss how this view relates to standard conceptions of pain as an internal object, a kind of perception, or as having both sensory-discriminative and affective-motivational aspects, and also how it sheds light on the question of awareness of pain.
Next, Kevin O’Regan will show how this outlook on pain has led to the idea that experienced pain has a cognitive component that is intertwined with the perceiver’s notion of “self”. Under this idea, if a person perceives part of their body as not belonging to them (as happens in some pathological conditions) then one might expect that pain in that body part should be reduced. This prediction was confirmed experimentally by using the paradigm of the “rubber hand illusion”, in which, through simultaneous stroking of a person’s unseen real hand and a visible rubber replica, sensed ownership of the person’s hand is transferred to the rubber hand. O’Regan and collaborators have recently shown that under these conditions of transferred ownership, sensitivity to painful heat stimulation delivered to the person’s hand significantly decreases.
Finally, Yoshio Nakamura will explore complex relationships between pain and suffering. The sensorimotor approach can make it possible for us to see a natural link between pain and suffering, since both can be understood as a reduction of an agent’s potential for action. Having recognized this link, we are confronted with the question of why this link exists at all, almost universally in all cultures. Although scientific understanding of “how the link gets established developmentally or evolutionarily” remains elusive now, a potentially interesting insight may be gained by examining how clinical interventions directed at pain relief work with patients with chronic pain. Specifically, it will be explored how mindfulness-based interventions can lessen suffering without necessarily reducing pain in chronic pain patients. This example should suggest that the natural link between pain and suffering is modifiable by mindfulness practices that can create neuroplastic changes in the brain. In order to make sense of this phenomenon, Yoshio Nakamura will consider measurements of pain and suffering from psychological (i.e., psychometric) perspective and will discuss how suffering can be conceptualized as a relational construct that reflects how pain impacts on quality of life in patients. To end, some speculations will be given on how suffering can be measured in empirically-oriented future studies.
