Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Curr Biol. 2017 Dec 18;27(24):3743-3751.e3. doi: 10.1016/j.cub.2017.10.062. Epub 2017 Nov 30.
The theta rhythm-a slow (6-12 Hz) oscillatory component of the local field potential-plays a critical role in spatial navigation and memory by coordinating the activity of neuronal ensembles within the medial temporal lobe (MTL). Although theta has been extensively studied in freely moving rodents, its presence in humans has been elusive and primarily investigated in stationary subjects. Here we used a unique clinical opportunity to examine theta within the human MTL during untethered, real-world ambulatory movement. We recorded intracranial electroencephalographic activity from participants chronically implanted with the wireless NeuroPace responsive neurostimulator (RNS) and tracked their motion with sub-millimeter precision. Our data revealed that movement-related theta oscillations indeed exist in humans, such that theta power is significantly higher during movement than immobility. Unlike in rodents, however, theta occurs in short bouts, with average durations of ∼400 ms, which are more prevalent during fast versus slow movements. In a rare opportunity to study a congenitally blind participant, we found that both the prevalence and duration of theta bouts were increased relative to the sighted participants. These results provide critical support for conserved neurobiological characteristics of theta oscillations during ambulatory spatial navigation, while highlighting some fundamental differences across species in these oscillations between humans and rodents.
θ 节律——局部场电位的缓慢（6-12Hz）振荡成分——通过协调内侧颞叶（MTL）内神经元集合的活动，在空间导航和记忆中发挥着关键作用。尽管θ节律在自由移动的啮齿动物中得到了广泛研究，但在人类中却难以捉摸，主要在静止的受试者中进行研究。在这里，我们利用一个独特的临床机会，在无束缚的真实世界的活动中，检查人类 MTL 中的θ节律。我们从长期植入无线 NeuroPace 反应性神经刺激器（RNS）的参与者中记录颅内脑电图活动，并以亚毫米精度跟踪他们的运动。我们的数据显示，运动相关的θ振荡确实存在于人类中，因此θ功率在运动时明显高于静止时。然而，与啮齿动物不同的是，θ在短时间内发生，平均持续时间约为 400ms，在快速运动时比在缓慢运动时更为常见。在一个难得的机会研究一个先天性盲人参与者时，我们发现，与视力正常的参与者相比，θ爆发的出现率和持续时间都增加了。这些结果为在活动空间导航过程中θ振荡的神经生物学特征的保守性提供了关键支持，同时强调了人类和啮齿动物之间这些振荡在物种间存在一些基本差异。
