Normal aging is associated with decline of motor timing mechanisms implicated in planning and execution of movement. Evidence from previous studies has highlighted the relationship between neural oscillatory activities and motor timing processing in neurotypical younger adults; however, it remains unclear how normal aging affects the underlying neural mechanisms of movement in older populations. In the present study, we recorded EEG activities in two groups of younger and older adults while they performed randomized speech and limb motor reaction time tasks cued by temporally predictable and unpredictable sensory stimuli. Our data showed that older adults were significantly slower than their younger counterparts during speech production and limb movement, especially in response to temporally unpredictable sensory stimuli. This behavioral effect was accompanied by significant desynchronization of alpha (7−12 Hz) and beta (13−25 Hz) band neural oscillatory activities in older compared with younger adults, primarily during the preparatory pre-motor phase of responses for speech production and limb movement. In addition, we found that faster motor reaction times in younger adults were significantly correlated with weaker desynchronization of pre-motor alpha and beta band neural activities irrespective of stimulus timing and response modality. However, the pre-motor components of alpha and beta activities were timing-specific in older adults and were more strongly desynchronized in response to temporally predictable sensory stimuli. These findings highlight the role of alpha and beta band neural oscillations in motor timing processing mechanisms and reflect their functional deficits during the planning phase of speech production and limb movement in normal aging.

正常衰老与涉及运动计划和执行的运动计时机制的下降有关。先前研究的证据强调了神经典型年轻人的神经振荡活动与运动时间处理之间的关系；然而，尚不清楚正常衰老如何影响老年人群运动的潜在神经机制。在本研究中，我们记录了两组年轻人和老年人的脑电图活动，他们在时间上可预测和不可预测的感官刺激提示下执行随机言语和肢体运动反应时间任务。我们的数据显示，老年人在言语产生和肢体运动方面明显慢于年轻人，尤其是在对时间上不可预测的感官刺激做出反应时。与年轻人相比，这种行为效应伴随着 alpha (7-12 Hz) 和 beta (13-25 Hz) 波段神经振荡活动的显着不同步，主要是在言语产生和肢体反应的准备运动前阶段移动。此外，我们发现，无论刺激时间和反应方式如何，年轻人更快的运动反应时间与运动前阿尔法和贝塔神经活动较弱的不同步显着相关。然而，阿尔法和贝塔活动的前运动成分在老年人中是特定于时间的，并且在响应时间可预测的感官刺激时更强烈地不同步。