Background: Alzheimer's disease (AD) is a well-known neurodegenerative disease that gradually induces neural network dysfunction and progressive memory deficits. Neural network activity is represented by rhythmic oscillations that influence local field potentials (LFPs). However, changes in hippocampal neural rhythmic oscillations in the early stage of AD remain largely unexplored. Objective: This study investigated neural rhythmic oscillations in 3-month-old APP/PS1 and 5x- FAD mice to assess early neural connectivity in AD. Methods: LFPs were recorded from the hippocampal CA1 region with implanted microelectrode arrays while the mice were in the awake resting stage. Welch fast Fourier transforms, continuous wavelet transforms, and phase-amplitude coupling analyses were used to compute the power density of different frequency bands and phase-amplitude modulation indices in the LFPs. Results: Our results showed impaired theta, low gamma, and high gamma frequency band power in APP/PS1 and 5xFAD mice during the awake resting stage. AD mice also showed decreased delta, alpha, and beta frequency band power. Impaired theta-low gamma and theta-high gamma phaseamplitude coupling were observed in 5xFAD mice. Conclusion: This study revealed neural network activity differences in oscillation power and cross-frequency coupling in the early stage of AD, providing a new perspective for developing biomarkers for early AD diagnosis.

中文翻译：

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不同阿尔茨海默病小鼠海马 CA1 区的神经振荡紊乱

背景：阿尔茨海默病（AD）是一种众所周知的神经退行性疾病，会逐渐诱发神经网络功能障碍和进行性记忆缺陷。神经网络活动由影响局部场电位 (LFP) 的节律振荡来表示。然而，AD 早期海马神经节律振荡的变化在很大程度上仍未被探索。目的：本研究调查了 3 个月大的 APP/PS1 和 5x-FAD 小鼠的神经节律振荡，以评估 AD 的早期神经连接。方法：在小鼠清醒静息阶段，通过植入微电极阵列记录海马CA1区的LFP。Welch 快速傅立叶变换、连续小波变换和相位幅度耦合分析用于计算 LFP 中不同频段的功率密度和相位幅度调制指数。结果：我们的结果显示 APP/PS1 和 5xFAD 小鼠在清醒静息阶段的 θ 频带功率受损、伽玛频带功率低、伽玛频带功率高。AD 小鼠还表现出 delta、alpha 和 beta 频带功率下降。在 5xFAD 小鼠中观察到 θ-低 γ 和 θ-高 γ 相位振幅耦合受损。结论：本研究揭示了AD早期神经网络在振荡功率和跨频耦合方面的活动差异，为开发AD早期诊断的生物标志物提供了新的视角。