Furtunato Alan M B, Lobão-Soares Bruno, Tort Adriano Bretanha Lopes, Belchior Hindiael
Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil.
Psychobiology Graduate Program, Federal University of Rio Grande do Norte, Natal, Brazil.
Front Behav Neurosci. 2020 Jun 23;14:101. doi: 10.3389/fnbeh.2020.00101. eCollection 2020.
Running speed affects theta (6-10 Hz) oscillations, the most prominent rhythm in the rat hippocampus. Many reports have found a strong positive correlation between locomotion speed and the amplitude and frequency of theta oscillations. However, less is known about how other rhythms such as delta (0.5-4 Hz) and gamma (25-100 Hz) are affected, and how consecutive runs impact oscillatory activity in hippocampal networks. Here, we investigated whether the successive execution of short-term runs modulates local field potentials (LFPs) in the rat hippocampus. To do this, we trained Long-Evans rats to perform voluntary 15-s runs at 30 cm/s on a treadmill placed on the central stem of an eight-shape maze, in which they subsequently performed a spatial alternation task. We bilaterally recorded CA1 LFPs while rats executed at least 35 runs on the treadmill-maze apparatus. Within running periods, we observed progressive increases in delta band power along with decreases in the power of the theta and gamma bands across runs. Concurrently, the inter-hemispheric phase coherence in the delta band significantly increased, while in the theta and gamma bands exhibited no changes. Delta power and inter-hemispheric coherence correlated better with the trial number than with the actual running speed. We observed no significant differences in running speed, head direction, nor in spatial occupancy across runs. Our results thus show that consecutive treadmill runs at the same speed positively modulates the power and coherence of delta oscillations in the rat hippocampus.
奔跑速度会影响θ波（6 - 10赫兹）振荡，这是大鼠海马体中最显著的节律。许多报告发现运动速度与θ波振荡的幅度和频率之间存在很强的正相关。然而，关于其他节律，如δ波（0.5 - 4赫兹）和γ波（25 - 100赫兹）如何受到影响，以及连续奔跑如何影响海马体网络中的振荡活动，人们了解得较少。在这里，我们研究了短期奔跑的连续执行是否会调节大鼠海马体中的局部场电位（LFP）。为此，我们训练Long - Evans大鼠在置于八字形迷宫中央主干上的跑步机上以30厘米/秒的速度进行15秒的自愿奔跑，随后它们在该迷宫中执行空间交替任务。当大鼠在跑步机 - 迷宫装置上至少执行35次奔跑时，我们双侧记录CA1区的LFP。在奔跑期间，我们观察到δ波段功率逐渐增加，同时θ波和γ波段的功率在每次奔跑中逐渐降低。同时，δ波段的半球间相位相干性显著增加，而θ波和γ波段则没有变化。δ波功率和半球间相干性与试验次数的相关性比与实际奔跑速度的相关性更好。我们观察到每次奔跑在奔跑速度、头部方向或空间占有率方面没有显著差异。因此，我们的结果表明，以相同速度连续在跑步机上奔跑会正向调节大鼠海马体中δ波振荡的功率和相干性。
