2024-06-11 韓国基礎科学研究院(IBS)
Figure 1. Overview of the fMRI experiment
Left: Fluids were delivered using an MR-compatible fluid delivery system (gustometer) and removed from participants’ mouths during the experiment using a suction device.
Middle: Capsaicin or chocolate fluid was delivered twice during the scan, with a duration of 1.5 minutes each for capsaicin fluid and a duration of 3 minutes each for chocolate fluid. The entire run lasted 14.5 minutes.
Right: Participants continuously rated pleasantness or unpleasantness (purple: pain, yellow: pleasure) while receiving capsaicin and chocolate (n = 58).
<関連情報>
- https://www.ibs.re.kr/cop/bbs/BBSMSTR_000000000738/selectBoardArticle.do?nttId=24826&pageIndex=1&searchCnd=&searchWrd=
- https://www.pnas.org/doi/10.1073/pnas.2310433121
快楽と苦痛の持続における情動価や強度の脳内表現 Brain representations of affective valence and intensity in sustained pleasure and pain
Soo Ahn Lee, Jae-Joong Lee, Jisoo Han, +2, and Choong-Wan Woo
Proceedings of the National Academy of Sciences Published:June 10, 2024
DOI:https://doi.org/10.1073/pnas.2310433121
Significance
Pleasure and pain, as fundamental emotional experiences, possess shared general affective dimensions such as positive vs. negative (i.e., affective valence) or weak vs. strong (i.e., affective intensity). The understanding of how these common affective dimensions across pleasure and pain are encoded in the brain carries significant clinical implications, particularly concerning pleasure-induced analgesia or anhedonia comorbid with chronic pain. Here, we identified brain representations of affective intensity and valence shared across pleasure and pain. These two representations were not only spatially nonoverlapping with each other but also functionally connected to distinct large-scale brain networks. Our findings support the existence of the modality-general affective coding in the brain, integrating distinct sensory information of pleasure and pain into general affective experiences.
Abstract
Pleasure and pain are two fundamental, intertwined aspects of human emotions. Pleasurable sensations can reduce subjective feelings of pain and vice versa, and we often perceive the termination of pain as pleasant and the absence of pleasure as unpleasant. This implies the existence of brain systems that integrate them into modality-general representations of affective experiences. Here, we examined representations of affective valence and intensity in an functional MRI (fMRI) study (n = 58) of sustained pleasure and pain. We found that the distinct subpopulations of voxels within the ventromedial and lateral prefrontal cortices, the orbitofrontal cortex, the anterior insula, and the amygdala were involved in decoding affective valence versus intensity. Affective valence and intensity predictive models showed significant decoding performance in an independent test dataset (n = 62). These models were differentially connected to distinct large-scale brain networks—the intensity model to the ventral attention network and the valence model to the limbic and default mode networks. Overall, this study identified the brain representations of affective valence and intensity across pleasure and pain, promoting a systems-level understanding of human affective experiences.
