Mok Robert M, Myers Nicholas E, Wallis George, Nobre Anna Christina
Department of Experimental Psychology and Oxford Centre for Human Brain Activity, University of Oxford, Oxford OX3 7JX, UK.
Cereb Cortex. 2016 Apr;26(4):1831-42. doi: 10.1093/cercor/bhw011. Epub 2016 Feb 9.
Working memory (WM) declines as we age and, because of its fundamental role in higher order cognition, this can have highly deleterious effects in daily life. We investigated whether older individuals benefit from flexible orienting of attention within WM to mitigate cognitive decline. We measured magnetoencephalography (MEG) in older adults performing a WM precision task with cues during the maintenance period that retroactively predicted the location of the relevant items for performance (retro-cues). WM performance of older adults significantly benefitted from retro-cues. Whereas WM maintenance declined with age, retro-cues conferred strong attentional benefits. A model-based analysis revealed an increase in the probability of recalling the target, a lowered probability of retrieving incorrect items or guessing, and an improvement in memory precision. MEG recordings showed that retro-cues induced a transient lateralization of alpha (8-14 Hz) and beta (15-30 Hz) oscillatory power. Interestingly, shorter durations of alpha/beta lateralization following retro-cues predicted larger cueing benefits, reinforcing recent ideas about the dynamic nature of access to WM representations. Our results suggest that older adults retain flexible control over WM, but individual differences in control correspond to differences in neural dynamics, possibly reflecting the degree of preservation of control in healthy aging.
随着年龄增长，工作记忆（WM）会衰退，由于其在高阶认知中起着基础性作用，这可能会在日常生活中产生极其有害的影响。我们研究了年长者是否能从工作记忆中注意力的灵活定向中受益，以减轻认知衰退。我们对正在执行工作记忆精确任务的老年人进行了脑磁图（MEG）测量，在维持期内会有线索，这些线索能追溯性地预测与表现相关项目的位置（追溯线索）。老年人的工作记忆表现显著受益于追溯线索。虽然工作记忆维持能力会随着年龄下降，但追溯线索带来了强大的注意力益处。基于模型的分析显示，回忆目标的概率增加，检索错误项目或猜测的概率降低，且记忆精度有所提高。脑磁图记录表明，追溯线索会诱发α（8 - 14赫兹）和β（15 - 30赫兹）振荡功率的短暂侧向化。有趣的是，追溯线索后α/β侧向化的持续时间越短，预示着线索益处越大，这强化了关于访问工作记忆表征动态性质的最新观点。我们的研究结果表明，老年人对工作记忆仍保持灵活控制，但控制方面的个体差异与神经动力学差异相对应，这可能反映了健康衰老过程中控制能力的保留程度。
