Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan.
Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Sleep Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan; Clinical Research Center, Tsoutun Psychiatric Center, Ministry of Health and Welfare, Nantou, Taiwan.
Exp Gerontol. 2023 Mar;173:112092. doi: 10.1016/j.exger.2023.112092. Epub 2023 Jan 17.
Aging causes brain function degeneration and slows many motor and behavioural responses. The hippocampal theta rhythm (4-12 Hz) is related to cognition and locomotion. However, the findings on aging-related changes in the frequency and amplitude of hippocampal theta oscillations have been inconsistent. We hypothesized that older rats have slower responses in terms of hippocampal theta rhythm during voluntary wheel running than do young adult rats. By simultaneously recording electroencephalography and physical activity (PA), we evaluated theta oscillations in 8-week-old (young adult) and 60-week-old (middle-aged) rats before and during wheel running, which was conducted only during the rats' 12-h dark period. To test the alterations of hippocampal theta rhythm in voluntary wheel running, we analyzed the signals without (8-s) or with (2-s) chronological order. No significant difference was observed in total frequency (TP, 4-12 Hz), low-frequency (LT, 4-6.5 Hz), or high-frequency (9.5-12 Hz) theta activity between active waking and overall running in either group. The theta oscillations were slower in the middle-aged rats than in the young adult rats during wheel running but increased during running for both age groups. During wheel running, the middle-aged rats exhibited an increased LT, which was related to PA. On the basis of the chronological order of running, the young adult rats exhibited increased TP, and the middle-aged rats exhibited significant increases in middle-frequency (MT, 6.5-9.5 Hz) theta activity. The dominant modulations of MT in the middle-aged rats may have caused nonsignificant changes in total activity. These between-group differences in theta rhythm characteristics during voluntary running provide insights into age-related brain function decline.
衰老导致大脑功能退化，并减缓许多运动和行为反应。海马θ节律（4-12 Hz）与认知和运动有关。然而，关于衰老与海马θ振荡频率和幅度变化的研究结果并不一致。我们假设，与年轻成年大鼠相比，老年大鼠在自愿轮跑过程中，海马θ节律的反应较慢。通过同时记录脑电图和身体活动（PA），我们评估了 8 周龄（年轻成年）和 60 周龄（中年）大鼠在轮跑前和轮跑期间的θ振荡，轮跑仅在大鼠的 12 小时暗期进行。为了测试自愿轮跑中海马θ节律的变化，我们分析了没有（8 秒）或有（2 秒）时间顺序的信号。在两组中，活跃觉醒和总跑步期间，总频率（TP，4-12 Hz）、低频（LT，4-6.5 Hz）或高频（9.5-12 Hz）θ活动均无显著差异。与年轻成年大鼠相比，中年大鼠在轮跑过程中θ振荡较慢，但两组大鼠在跑步过程中均增加。在轮跑过程中，中年大鼠的 LT 增加，这与 PA 有关。基于跑步的时间顺序，年轻成年大鼠的 TP 增加，中年大鼠的中频（MT，6.5-9.5 Hz）θ活动显著增加。中年大鼠 MT 的主要调制可能导致总活动无显著变化。这些在自愿跑步过程中，不同年龄组之间θ节律特征的差异为年龄相关的大脑功能衰退提供了新的见解。
