Manno Francis A M, Kumar Rachit, An Ziqi, Khan Muhammad Shehzad, Su Junfeng, Liu Jiaming, Wu Ed X, He Jufang, Feng Yanqiu, Lau Condon
Center for Imaging Science, Department of Biomedical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, United States.
Department of Physics, City University of Hong Kong, Hong Kong, Hong Kong SAR, China.
Front Syst Neurosci. 2022 Feb 15;15:807297. doi: 10.3389/fnsys.2021.807297. eCollection 2021.
Environmental enrichment is known to induce neuronal changes; however, the underlying structural and functional factors involved are not fully known and remain an active area of study. To investigate these factors, we assessed enriched environment (EE) and standard environment (SE) control mice over 30 days using structural and functional MRI methods. Naïve adult male mice ( = 30, ≈20 g, C57BL/B6J, postnatal day 60 initial scan) were divided into SE and EE groups and scanned before and after 30 days. Structural analyses included volumetry based on manual segmentation as well as diffusion tensor imaging (DTI). Functional analyses included seed-based analysis (SBA), independent component analysis (ICA), the amplitude of low-frequency fluctuation (ALFF), and fractional ALFF (fALFF). Structural results indicated that environmental enrichment led to an increase in the volumes of cornu ammonis 1 (CA1) and dentate gyrus. Structural results indicated changes in radial diffusivity and mean diffusivity in the visual cortex and secondary somatosensory cortex after EE. Furthermore, SBA and ICA indicated an increase in resting-state functional MRI (rsfMRI) functional connectivity in the hippocampus. Using parallel structural and functional analyses, we have demonstrated coexistent structural and functional changes in the hippocampal subdivision CA1. Future research should map alterations temporally during environmental enrichment to investigate the initiation of these structural and functional changes.
已知环境富集可诱导神经元变化；然而，其中涉及的潜在结构和功能因素尚不完全清楚，仍是一个活跃的研究领域。为了研究这些因素，我们使用结构和功能磁共振成像方法，对富集环境（EE）和标准环境（SE）对照小鼠进行了30天的评估。将成年雄性小鼠（n = 30，约20 g，C57BL/B6J，出生后第60天进行初次扫描）分为SE组和EE组，并在30天前后进行扫描。结构分析包括基于手动分割的容积测量以及扩散张量成像（DTI）。功能分析包括基于种子点的分析（SBA）、独立成分分析（ICA）、低频波动幅度（ALFF）和分数ALFF（fALFF）。结构结果表明，环境富集导致海马体1区（CA1）和齿状回的体积增加。结构结果表明，EE后视觉皮层和次级体感皮层的径向扩散率和平均扩散率发生了变化。此外，SBA和ICA表明静息态功能磁共振成像（rsfMRI）在海马体中的功能连接性增加。通过并行的结构和功能分析，我们证明了海马体CA1亚区存在结构和功能的共存变化。未来的研究应在环境富集期间对变化进行时间映射，以研究这些结构和功能变化的起始情况。
