
痛みの表情は、痛みに関連する脳活動の独自の情報を伝えるものである。


coremsg

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge on the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a Facial Expression of Pain Signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.

### Competing Interest Statement

The authors have declared no competing interest.

Participants did not provide informed consent for the sharing of individual data but unthresholded group maps are available upon request. Unthresholded and thresholded FEPS patterns are available on Neurovault (<https://neurovault.org/collections/13924/>). The SIIPS-1, the PVP and the TPAS are available on Github ([https://github.com/canlab/Neuroimaging\_Pattern\_Masks][1]). The NPS is available upon request from T.D.W.

 [1]: https://github.com/canlab/Neuroimaging_Pattern_Masks

A distributed brain response predicting the facial expression of acute nociceptive pain

痛みの表情は脳の痛み処理における特徴的な行動マーカーである