ABSTRACT

The brain undergoes substantial structural and functional remodeling during adolescence, including alterations in memory-processing regions influenced by stress. This study evaluated brain activation using functional magnetic resonance imaging (fMRI) during spatial memory performance using a virtual Morris water task (MWT) and examined the associations between default mode network (DMN) activation, task performance, and perceived stress and rejection. Functional magnetic resonance imaging data were acquired at 3 Tesla from 59 (34 female) adolescents (13–14 years). The NIH Emotion Toolbox was used to measure perceived stress and rejection. During the MWT, hippocampus and prefrontal cortex showed greater activation during memory retrieval relative to motor performance. Templates of brain functional networks from the Human Connectome Project study were used to extract individual participants’ brain network activation strengths for the retrieval > motor contrast for two sub-networks of the default mode network: medial temporal lobe (MTL-DMN) and dorsomedial prefrontal (dMPFC-DMN). For the MTL-DMN sub-network only, activation was significantly associated with worse MWT performance (p = .008) and greater perceived stress (p = .008) and perceived rejection (p = .002). Further, MWT performance was negatively associated with perceived rejection (p = .007). These findings suggest that perceived stress and rejection are related to engagement of MTL-DMN during spatial memory and that engagement of this network impacts performance. These findings also demonstrate the utility of examining task-related network activation strength to identify the impact of perceived stress and rejection on large-scale brain network functioning during adolescence.

摘要

大脑在青春期经历了大量的结构和功能重塑，包括受压力影响的记忆处理区域的改变。本研究使用虚拟莫里斯水任务 (MWT) 在空间记忆性能期间使用功能磁共振成像 (fMRI) 评估大脑激活，并检查默认模式网络 (DMN) 激活、任务性能以及感知压力和拒绝之间的关联。功能性磁共振成像数据是在 3 特斯拉下从 59 名（34 名女性）青少年（13-14 岁）中采集的。NIH 情绪工具箱用于测量感知压力和拒绝。在 MWT 期间，海马体和前额叶皮层在记忆检索过程中相对于运动表现表现出更大的激活。来自人类连接组项目研究的大脑功能网络模板被用于提取个体参与者的大脑网络激活强度，用于默认模式网络的两个子网络的检索 > 运动对比：内侧颞叶 (MTL-DMN) 和背内侧前额叶(dMPFC-DMN)。仅对于 MTL-DMN 子网络，激活与更差的 MWT 性能 (p = .008) 和更大的感知压力 (p = .008) 和感知拒绝 (p = .002) 显着相关。此外，MWT 性能与感知拒绝呈负相关 (p = .007)。这些发现表明，感知到的压力和拒绝与空间记忆期间 MTL-DMN 的参与有关，并且该网络的参与会影响性能。