Schmid College of Science and Technology, Chapman University, Orange, CA, USA.
Department of Biology, Reed College, Portland, OR, USA.
Brain Behav Immun. 2023 May;110:162-174. doi: 10.1016/j.bbi.2023.03.004. Epub 2023 Mar 5.
Sick animals display drastic changes in their behavioral patterns, including decreased activity, decreased food and water intake, and decreased interest in social interactions. These behaviors, collectively called "sickness behaviors", can be socially modulated. For example, when provided with mating opportunities, males of several species show reduced sickness behaviors. While the behavior is known to change, how the social environment affects neural molecular responses to sickness is not known. Here, we used a species, the zebra finch, Taeniopygia guttata, where males have been shown to decrease sickness behaviors when presented with novel females. Using this paradigm, we obtained samples from three brain regions (the hypothalamus, the bed nucleus of the stria terminalis, and the nucleus taeniae) from lipopolysaccharide (LPS) or control treated males housed under four different social environments. Manipulation of the social environment rapidly changed the strength and co-expression patterns of the neural molecular responses to the immune challenge in all brain regions tested, therefore suggesting that the social environment plays a significant role in determining the neural responses to an infection. In particular, brains of males paired with a novel female showed muted immune responses to LPS, as well as altered synaptic signaling. Neural metabolic activity in response to the LPS challenge was also affected by the social environment. Our results provide new insights into the effects of the social environment on brain responses to an infection, thereby improving our understanding of how the social environment can affect health.
患病动物的行为模式会发生剧烈变化，包括活动减少、食物和水摄入减少以及对社交互动的兴趣降低。这些行为统称为“患病行为”，可以受到社交环境的调节。例如，当提供交配机会时，一些物种的雄性会表现出减少患病行为。虽然这种行为是已知会发生变化的，但社交环境如何影响对疾病的神经分子反应尚不清楚。在这里，我们使用了一种物种，即斑胸草雀，发现当雄性面对新的雌性时，它们的患病行为会减少。使用这种范式，我们从三个脑区（下丘脑、终纹床核和终纹核）获得了接受脂多糖 (LPS) 或对照处理的雄性在四种不同社交环境下的样本。社交环境的操纵迅速改变了所有测试脑区对免疫挑战的神经分子反应的强度和共表达模式，因此表明社交环境在决定对感染的神经反应方面起着重要作用。特别是，与新雌性配对的雄性大脑对 LPS 的免疫反应减弱，同时突触信号也发生改变。对 LPS 挑战的神经代谢活性也受到社交环境的影响。我们的研究结果为社交环境对大脑对感染的反应的影响提供了新的见解，从而提高了我们对社交环境如何影响健康的理解。
