Ognjanovski Nicolette, Kim David S, Charlett-Green Emma, Goldiez Ethan, van Koppen Sofie, Aton Sara J, Watson Brendon O
Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, USA.
Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.
Eur J Neurosci. 2025 Jan;61(1):e16619. doi: 10.1111/ejn.16619. Epub 2024 Dec 11.
The adaptation to the daily 24-h light-dark cycle is ubiquitous across animal species and is crucial for maintaining fitness. This free-running cycle occurs innately within multiple bodily systems, such as endogenous circadian rhythms in clock-gene expression and synaptic plasticity. These phenomena are well studied; however, it is unknown if and how the 24-h clock affects electrophysiologic network function in vivo. The hippocampus is a region of interest for long timescale (>8 h) studies because it is critical for cognitive function and exhibits time-of-day effects in learning. We recorded single cell spiking activity and local field potentials (LFPs) in mouse hippocampus across the 24-h (12:12-h light/dark) cycle to quantify how electrophysiological network function is modulated across the 24-h day. We found that while inhibitory population firing rates and LFP oscillations exhibit modulation across the day, average excitatory population firing is static. This excitatory stability, despite inhibitory dynamism, may enable consistent around-the-clock function of neural circuits.
对每日24小时昼夜循环的适应在所有动物物种中普遍存在，对维持健康至关重要。这种自主运行的循环在多个身体系统中内在地发生，例如时钟基因表达和突触可塑性中的内源性昼夜节律。这些现象已得到充分研究；然而，24小时生物钟是否以及如何影响体内电生理网络功能尚不清楚。海马体是长时间尺度（>8小时）研究的一个感兴趣区域，因为它对认知功能至关重要，并且在学习中表现出昼夜效应。我们在24小时（12:12小时光照/黑暗）循环中记录了小鼠海马体中的单细胞放电活动和局部场电位（LFP），以量化电生理网络功能在24小时内是如何被调节的。我们发现，虽然抑制性群体放电率和LFP振荡在一天中表现出调节，但平均兴奋性群体放电是静态的。尽管存在抑制性动态变化，但这种兴奋性稳定性可能使神经回路能够全天候持续发挥功能。
