The modulation of neural insular activity by a brain computer interface differentially affects pain discrimination

Philipp Taesler,Michael Rose

doi:10.1038/s41598-021-89206-3

Philipp Taesler, Michael Rose

Open Access

https://doi.org/10.1038/s41598-021-89206-3

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Abstract

The experience of pain is generated by activations throughout a complex pain network with the insular cortex as a central processing area. The state of ongoing oscillatory activity can influence subsequent processing throughout this network. In particular the ongoing theta-band power can be relevant for later pain processing, however a direct functional relation to post-stimulus processing or behaviour is missing. Here, we used a non-invasive brain–computer interface to either increase or decrease ongoing theta-band power originating in the insular cortex. Our results show a differential modulation of oscillatory power and even more important a transfer to independently measured pain processing and sensation. Pain evoked neural power and subjective pain discrimination were differentially affected by the induced modulations of the oscillatory state. The results demonstrate a functional relevance of insular based theta-band oscillatory states for the processing and subjective discrimination of nociceptive stimuli and offer the perspective for clinical applications.

Highlights

The experience of pain is generated by activations throughout a complex pain network with the insular cortex as a central processing area
Separate t tests for the up and down group revealed that power was modulated significantly from the first to the last training session for both directions (up: p = 0.032, t(9) = 2.52, down: p = 0.02, t(9) = − 4.3)
Previous studies indicated the insular cortex is an integral part of the pain processing network the function is not exclusively pain specific[27], but contribute important partial information on the magnitude of the resulting percept[2,17]

Summary

Introduction

The experience of pain is generated by activations throughout a complex pain network with the insular cortex as a central processing area. The importance of pre-stimulus activity for pain processing was further demonstrated in an fMRI study, that showed that the functional connectivity of the anterior insula with the brainstem prior to stimulus presentation determines whether a noxious event is perceived as painful[21] It was shown, that the prestimulus fMRI signals in the default-mode network predict the subsequent magnitude of pain ratings, evoked potentials and pain network BOLD r esponse[22]. In both studies the rating of a constant stimulus varied across measures to a high degree (in some volunteers about 80% on the VAS for the identical stimulus) which resulted in the perception of different stimuli the intensity was always identical This demonstrated that the subjective feeling of a pain intensity as well as the discrimination of the input with respect to the pain domain is affected by several parameters including the pre-stimulus state of neural activity. The consequences on pain processing were examined at the neural level by the evaluation of stimulus evoked theta-band power

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