Neuronal Mechanisms of Pain Modulation by Drive State Competition
Human Cognitive and Systems Neuroscience
Final Report Abstract
Human and animal behavior is shaped by strong motivational drive states such as thirst, hunger, or pain. When any the demands imposed by these drive states are not met, homeostasis and, ultimately, survival is endangered. However, many of these drive states may be present simultaneously. Therefore, humans and animals must internally prioritize which demands to meet first and which demands to meet later. Previous research in animals suggests that the competition between drive states such as thirst and pain may result in a downregulation of pain. After prioritization of one internal drive state over the other, suppression of the competing drive frees resources and maximizes chances for survival. Because such drives are fundamental to human behavior, studying drive state competition can provide important insights into human motivational systems. Here, we aimed to study human drive state competition by examining interactions between a primary appetitive (thirst) and a primary aversive drive state (pain). Furthermore, expectations fundamentally shape pain perception. While it is well established that human pain is influenced by the mean estimate provided by cues before the pain stimulation, it is unclear which and how other features of the cue distribution affect perception. For example, extreme outliers could signal a potentially very harmful pain stimulus despite a low mean and could lead to caution. We aimed to test the influence of different features of the information provided by cues on perception and their underlying neuronal processes. Related to our first set of hypotheses, comparing a group of thirsty participants against a control group revealed increased heat pain perception for the thirsty group. A mediation analysis revealed that subjective thirst mediated this effect and at the same time acted as a suppressor. Controlling for the subjective thirst revealed that the thirst group assignment was negatively related to pain perception. A recent study in mice suggested that competing drives suppress chronic pain, but not acute pain. This differentiation could explain the positive main effect of group in our study of acute heat pain and thirst. With regard to the influence of expectation effects on perception, we observed that participants’ expectations were influenced by the mean of the cue distributions. Furthermore, we observed that participants incorporated outliers into their expectations. We are currently analyzing the functional brain imaging data to elucidate the underlying neuronal processes associated with expectation-based modulation of perception.
Publications
- (2016) Disentangling opposing effects of motivational states on pain perception: PAIN Reports 1:e574
Geuter S, Cunningham JT, Wager TD
(See online at https://doi.org/10.1097/PR9.0000000000000574) - (2017) Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula. eLife 6:e24770
Geuter S, Boll S, Eippert F, Büchel C
(See online at https://doi.org/10.7554/eLife.24770) - (2017) The Cognitive Neuroscience of Placebo Effects: Concepts, Predictions, and Physiology. Annual Review of Neuroscience 40:167–188
Geuter S, Koban L, Wager TD
(See online at https://doi.org/10.1146/annurev-neuro-072116-031132) - (2018) Multiple brain networks mediating stimulus-pain relationships in humans
Geuter S, Losin EAR, Roy M, Atlas LY, Schmidt L, Krishnan A, Koban L, Wager TD, Lindquist MA
(See online at https://doi.org/10.1101/298927)
