Moyne Maëva, Durand-Ruel Manon, Park Chang-Hyun, Salamanca-Giron Roberto, Sterpenich Virgine, Schwartz Sophie, Hummel Friedhelm C, Morishita Takuya
Defitech Chair of Clinical Neuroengineering, Neuro X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland.
Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, Sion, Switzerland.
Sleep Adv. 2025 Mar 26;6(2):zpaf022. doi: 10.1093/sleepadvances/zpaf022. eCollection 2025 Apr.
With the increase in life expectancy and the rapid evolution of daily life technologies, older adults must constantly learn new skills to adapt to society. Sleep reinforces skills acquired during the day and is associated with the occurrence of specific oscillations such as spindles. However, with age, spindles deteriorate and thus likely contribute to memory impairments observed in older adults. The application of electric currents by means of transcranial alternating current stimulation (tACS) with spindle-like waveform, applied during the night, was found to enhance spindles and motor memory consolidation in young adults. Here, we tested whether tACS bursts inspired by spindles applied during daytime naps may (i) increase spindle density and (ii) foster motor memory consolidation in older adults. Twenty-six healthy older participants performed a force modulation task at 10:00, were retested at 16:30, and the day after the initial training. They had 90-minute opportunity to take a nap while verum or placebo spindle-inspired tACS bursts were applied with similar temporal parameters to those observed in young adults and independently of natural spindles, which are reduced in the elderly. We show that the density of natural spindles correlates with the magnitude of memory consolidation, thus confirming that spindles are promising physiological targets for enhancing memory consolidation in older adults. However, spindle-inspired tACS, as used in the present study, did not enhance either spindles or memory consolidation. We therefore suggest that applying tACS time-locked to natural spindles might be required to entrain them and improve their related functions.
随着预期寿命的增加和日常生活技术的迅速发展，老年人必须不断学习新技能以适应社会。睡眠强化白天习得的技能，并与特定的脑电振荡（如纺锤波）的出现有关。然而，随着年龄增长，纺锤波会退化，这可能是导致老年人出现记忆障碍的原因之一。研究发现，在夜间施加类似纺锤波波形的经颅交流电刺激（tACS），可增强年轻人的纺锤波和运动记忆巩固。在此，我们测试了白天小睡期间施加受纺锤波启发的tACS脉冲是否（i）能增加老年人的纺锤波密度，以及（ii）促进老年人的运动记忆巩固。26名健康的老年参与者在10:00进行了一次力量调制任务，在16:30进行了复测，并在初次训练后的第二天再次测试。他们有90分钟的小睡时间，期间施加真刺激或安慰剂刺激，即受纺锤波启发的tACS脉冲，其时间参数与在年轻人中观察到的相似，且与老年人中减少的自然纺锤波无关。我们发现，自然纺锤波的密度与记忆巩固的程度相关，从而证实纺锤波是增强老年人记忆巩固的有前景的生理靶点。然而，本研究中使用的受纺锤波启发的tACS并没有增强纺锤波或记忆巩固。因此，我们建议可能需要将tACS与自然纺锤波进行时间锁定以诱导它们并改善其相关功能。
