Background & Aims

Reinforcement learning plays an important role in the development and maintenance of chronic pain. A recent study revealed that individuals with chronic back pain compared to non-clinical controls (NCC) show increased fronto-striatal responses towards positive reinforcement signals but impaired signal encoding during learning from reward in an operant learning experiment (Löffler et al., 2022). These impairments in reinforcement learning may be enhanced in individuals with comorbid anxiety or depression (e.g. Cavanagh et al., 2019). However, previous studies on reinforcement learning in chronic pain have particularly compared individuals with and without chronic pain without considering psychosocial characteristics of individuals with chronic pain. Therefore, this study aimed to investigate differences in reward learning in psychosocial subgroups of individuals with chronic musculoskeletal pain (CMSP).

Methods

In this study, 90 individuals with CMSP and 30 NCC underwent an operant learning paradigm during functional magnetic resonance imaging (fMRI) while positive reinforcement was provided by monetary reward, and pain relief was used as negative reinforcement. Based on their results in the German version of the West Haven-Yale Multidimensional Pain Inventory (Kerns et al., 1985; Flor et al., 1990), each individual with CMSP was allocated to one of three previously identified clusters: a dysfunctional cluster, an interpersonally distressed cluster, or an adaptive coper cluster (Turk and Rudy, 1988). We compared blood oxygen level dependent (BOLD) responses in the ventromedial prefrontal cortex and in the nucleus accumbens during distinct reinforcement learning processes, between subgroups of individuals with CMSP. In addition, we used multivariate pattern analyses to discriminate activity patterns in the brain between different subgroups of individuals with CMSP.

Results

We present CMSP subgroup-specific brain activity in response to a discriminative stimulus indicating positive reinforcement, during positive prediction error (i.e. feedback on receipt of higher reinforcement than expected), and during negative prediction error (i.e. feedback on receipt of lower reinforcement than expected). We further report on specific learning-related activity patterns in the ventromedial prefrontal cortex and in the nucleus accumbens that distinguish subgroups of participants with CMSP. Finally, we associate results on the brain level with valence and arousal ratings of the discriminative stimuli signalling positive and negative reinforcement.

Conclusions

The results of this study contribute to a better understanding of mechanistic subgroups of individuals with chronic pain, an important step towards the development of individualized mechanism-based interventions in the treatment of chronic pain.

References

Cavanagh, J. F., Bismark, A. W., Frank, M. J., & Allen, J. J. (2019). Multiple dissociations between comorbid depression and anxiety on reward and punishment processing: Evidence from computationally informed EEG. Computational Psychiatry (Cambridge, Mass.), 3, 1.
Flor, H., Rudy, T. E., Birbaumer, N., Streit, B., & Schugens, M. M. (1990). The applicability of the West Haven-Yale multidimensional pain inventory in German-speaking countries. Data on the reliability and validity of the MPI-D: Daten zur Reliabilität und Validität des MPI-D. Der Schmerz, 4, 82-87.
Kerns, R. D., Turk, D. C., & Rudy, T. E. (1985). The west haven-yale multidimensional pain inventory (WHYMPI). Pain, 23(4), 345-356.
Löffler, M., Levine, S. M., Usai, K., Desch, S., Kandi?, M., Nees, F., & Flor, H. (2022). Corticostriatal circuits in the transition to chronic back pain: the predictive role of reward learning. Cell Reports Medicine, 3(7).
Turk, D. C., & Rudy, T. E. (1988). Toward an empirically derived taxonomy of chronic pain patients: Integration of psychological assessment data. Journal of Consulting and Clinical Psychology, 56(2), 233–238.

Presenting Author

Annette Löffler

Poster Authors

Annette Löffler

MSc

Scientific Center for Neuropathic Pain Aachen (SCN)

Lead Author

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Sebastian Keil

Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Germany

Lead Author

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Philipp Seidel

PhD

Tübingen Center for Mental Health, University of Tübingen, Germany

Lead Author

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Jonas Tesarz

University Hospital Heidelberg

Lead Author

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Herta Flor

Interdisciplinary Center for Clinical Trials, Johannes Gutenberg University Medical Center Mainz

Lead Author

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Martin Löffler

Clinical Psychology, Department of Experimental Psychology, Heinrich Heine University Düsseldorf

Lead Author

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Topics

  • Mechanisms: Psychosocial and Biopsychosocial