Department of Psychology, University of California, Los Angeles, 1285 Franz Hall, Los Angeles, CA 90095, United States.
Department of Psychology, University of California, Los Angeles, 1285 Franz Hall, Los Angeles, CA 90095, United States; Department of Communication, University of California, Los Angeles, 2330 Rolfe Hall, Los Angeles, CA 90095, United States.
Brain Behav Immun. 2022 Feb;100:48-54. doi: 10.1016/j.bbi.2021.11.011. Epub 2021 Nov 19.
Humans are able to discern the health status of others using olfactory and visual cues, and subsequently shift behavior to make infection less likely. However, little is known about how this process occurs. The present study examined the neural regions involved in differentiating healthy from sick individuals using visual cues.
While undergoing a functional magnetic resonance imaging scan, participants (N = 42) viewed facial photos of 30 individuals (targets) who had been injected with an inflammatory challenge--low-dose endotoxin (i.e., sick) or placebo (i.e., healthy), and rated how much they liked each face. We examined regions implicated in processing either threat (amygdala, anterior insula) or cues that signal safety (ventromedial prefrontal cortex [VMPFC]), and how this activity related to their liking of targets and cytokine levels (interleukin-6, tumor necrosis factor-α) exhibited by the targets.
Photos of sick faces were rated as less likeable compared to healthy faces, and the least liked faces were those individuals with the greatest inflammatory response. While threat-related regions were not significantly active in response to viewing sick faces, the VMPFC was more active in response to viewing healthy (vs. sick) faces. Follow-up analyses revealed that participants tended to have lower VMPFC activity when viewing the least liked faces and the faces of those with the greatest inflammatory response.
This work builds on prior work implicating the VMPFC in signaling the presence of safe, non-threatening visual stimuli, and suggests the VMPFC may be sensitive to cues signaling relative safety in the context of pathogen threats.
人类能够通过嗅觉和视觉线索辨别他人的健康状况，并相应地改变行为，降低感染的可能性。然而，人们对这一过程是如何发生的知之甚少。本研究通过视觉线索来考察区分健康和患病个体的神经区域。
在进行功能磁共振成像扫描时，参与者（N=42）观看了 30 个人的面部照片（目标），这些人已经接受了炎症挑战——低剂量内毒素（即患病）或安慰剂（即健康）的注射，并对他们对每张脸的喜爱程度进行了评分。我们考察了参与处理威胁（杏仁核、前岛叶）或信号安全的线索（腹内侧前额叶皮层 [VMPFC]）的区域，以及这种活动与他们对目标的喜爱程度和目标表现出的细胞因子水平（白细胞介素-6、肿瘤坏死因子-α）之间的关系。
与健康面孔相比，患病面孔的照片被评为不太讨人喜欢，而最不受欢迎的面孔是那些炎症反应最强烈的个体。虽然威胁相关区域在观看患病面孔时没有显著活跃，但 VMPFC 在观看健康（而非患病）面孔时更活跃。后续分析表明，当参与者观看最不受欢迎的面孔和炎症反应最强烈的个体的面孔时，他们的 VMPFC 活动往往较低。
这项工作是对先前研究的进一步扩展，表明 VMPFC 在信号传递安全、无威胁的视觉刺激方面具有重要作用，并表明 VMPFC 可能对病原体威胁背景下表示相对安全的线索敏感。
