Department of Bioengineering, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, United States.
Department of Electrical Engineering, University of California, Los Angeles, 56-147E Engineering IV Building, 420 Westwood Plaza, Box 951594, Los Angeles, CA 90095, United States.
Exp Neurol. 2018 Feb;300:259-273. doi: 10.1016/j.expneurol.2017.10.021. Epub 2017 Oct 21.
Certain deficits of episodic memory among young adults are the delayed consequences of an earlier mild or moderate Traumatic Brain Injury (mTBI). We examined alterations in hippocampal Local Field Oscillations (LFOs) of equivalently-impaired juvenile rodents to identify reliable functional markers of single-incidence mTBI. Two persistent, behavior-dependent, electrophysiological markers of injury were identified in the absence of external physiological symptoms by the analysis of wirelessly-transmitted hippocampal LFOs (3-80Hz) during repeat measures of the Novel Object Recognition (NOR) paradigm. Using a new method for detecting functional network activity at a single recording site, we correlated instantaneous increases in theta frequency and gamma magnitude with injury during periods of functional network organization and dissolution, presented here as Theta Epochs (TEs) and Theta Non-Epochs (TNEs), respectively. We estimated the efficacy of networks across pairs of such sites using new metrics such as the Coherence of Theta Phase (PCOH) and Inter-Epoch Intervals (IEIs) and demonstrated that behavioral deficits observed during the NOR testing stage correspond to electrophysiological deficits recorded during the preceding NOR familiarization stage. Increased theta frequency during TNEs and increased smoothness of PCOH during TEs were found to be robust markers of injury during memory-reliant behaviors.
某些年轻人的情景记忆缺陷是早期轻度或中度创伤性脑损伤 (mTBI) 的延迟后果。我们研究了同等受损的幼年啮齿动物海马体局部场振荡 (LFO) 的变化，以确定单次 mTBI 的可靠功能标志物。在没有外部生理症状的情况下，通过对无线传输的海马体 LFO（3-80Hz）进行重复的新物体识别（NOR）范式分析，确定了两种持续的、行为依赖性的损伤的电生理标志物。使用一种新的方法在单个记录位点检测功能网络活动，我们将瞬时增加的 theta 频率和 gamma 幅度与功能网络组织和溶解期间的损伤相关联，这里分别表示为 theta 期（TEs）和 theta 非期（TNEs）。我们使用新的指标（如 theta 相位相干性（PCOH）和区间内间隔（IEIs））来估计这些位点对之间的网络效能，并证明在 NOR 测试阶段观察到的行为缺陷与在先前的 NOR 熟悉阶段记录的电生理缺陷相对应。在 TNEs 期间增加 theta 频率和在 TEs 期间增加 PCOH 的平滑度被发现是与记忆相关行为期间损伤的稳健标志物。
