Amador P, López M, Cuesta-López I, Jove C, Tomas-Zapico C, Begega A
Department of Functional Biology (Physiology), University of Oviedo, Asturias 33006, Spain; Health Research Institute of the Principality of Asturias (ISPA), Asturias 33011, Spain.
Basic Psychology Area, Faculty of Psychology, Principado de Asturias, Institute of Neuroscience of Principado Asturias INEUROPA, Plaza Feijoo s/n, Oviedo 33003, Spain.
Behav Brain Res. 2025 Jun 5;487:115574. doi: 10.1016/j.bbr.2025.115574. Epub 2025 Apr 5.
The COVID-19 pandemic has underscored the impact of social isolation on mental well-being. This study aims to evaluate the emotional and cerebral consequences of social isolation and assess whether prior environmental enrichment can mitigate the adverse effects. For that purpose, four groups were established: Behaviour group (Beh), n=8, subjected to a 4 % sucrose consumption test and the elevated zero maze (EZM) to assess anhedonia and unconditioned anxiety; Social isolation (SI) + Behaviour group, n=8, subjected to 4 consecutive weeks of social isolation followed by the behavioural testing; Environmental enrichment: EE+SI + Behaviour group, n = 8, subjected to EE prior to SI followed by behavioural assessment; and Basal group (BG), n = 8, used to determine the baseline of cytochrome c-oxidase (CCO). After behavioural testing, brain tissue from the prefrontal cortex (PFC), dorsal and ventral hippocampus (vHIP), nucleus accumbens (NAc), and ventral tegmental area (VTA) were analysed for CCO activity. Results show that SI serves as a significant stressor, increasing anxiety and anhedonic responses in the SI group. However, pre-exposure to EE significantly reduced these responses. Regarding CCO activity, the SI group exhibited elevated levels across all brain regions compared to the EE+SI group. Moreover, the EE+SI group maintained CCO activity levels similar to those of the Basal group, suggesting that prior EE exposure mitigates the metabolic impact of social isolation across most brain regions, except for the vHIP. These results indicate that pre-exposure to an EE may buffer the adverse effects of SI, supporting enhanced resilience.
新冠疫情凸显了社交隔离对心理健康的影响。本研究旨在评估社交隔离对情绪和大脑的影响，并评估先前的环境丰富化是否能减轻这些不利影响。为此，设立了四组：行为组（Beh），n = 8，进行4%蔗糖消耗试验和高架零迷宫（EZM）以评估快感缺失和无条件焦虑；社交隔离（SI）+行为组，n = 8，连续4周进行社交隔离，然后进行行为测试；环境丰富化：EE+SI +行为组，n = 8，在社交隔离前进行环境丰富化，然后进行行为评估；以及基础组（BG），n = 8，用于确定细胞色素c氧化酶（CCO）的基线。行为测试后，分析前额叶皮层（PFC）、背侧和腹侧海马体（vHIP）、伏隔核（NAc）和腹侧被盖区（VTA）的脑组织中的CCO活性。结果表明，社交隔离是一个重要的应激源，增加了SI组的焦虑和快感缺失反应。然而，预先暴露于环境丰富化显著降低了这些反应。关于CCO活性，与EE+SI组相比，SI组在所有脑区的水平都有所升高。此外，EE+SI组的CCO活性水平与基础组相似，这表明预先暴露于环境丰富化可减轻社交隔离对大多数脑区的代谢影响，但vHIP除外。这些结果表明，预先暴露于环境丰富化可能缓冲社交隔离的不利影响，支持增强恢复力。
