Max Planck Institute for Human Development, Berlin, Germany.
Neuroimage. 2012 Jan 2;59(1):646-54. doi: 10.1016/j.neuroimage.2011.06.092. Epub 2011 Jul 7.
Working memory (WM) capacity increases across childhood, peaks in young adulthood, and declines thereafter. Developmental and aging theories suggest that deficient inhibitory control processes in children and older adults may underlie the lower performance relative to younger adults. Recently, oscillatory alpha power (7-13 Hz) of the electroencephalogram (EEG) has been suggested as a neural marker of inhibition processes contributing to WM performance (Sauseng et al., 2009). We examined 20 children (10-13 years), 12 younger adults (20-26 years), and 20 older adults (70-76 years) in a cued change-detection paradigm. Behaviorally, we observed the expected lifespan peak in younger adults. EEG alpha power was generally reduced in older adults compared to children and younger adults. In line with previous research, hemispheric differences in alpha power related to attention and WM processes during the retention interval increased with load in younger adults. In children and older adults, lateralized alpha power increased from low to medium load conditions, but decreased for high load conditions. Furthermore, older adults showed higher inter-trial phase stability shortly after stimulus onset compared to children and younger adults. Our results show that inhibitory control processes as indexed by local alpha power modulations can be observed in children and older adults but seem to break down when WM load is high. In addition, older adults are more entrained by external stimulation what may increase a need for inhibitory control during later processing. We conclude that differences in inhibitory control processes and information uptake as reflected in amplitude modulations and inter-trial phase stability of alpha rhythms interactively determine WM constraints across the lifespan.
工作记忆（WM）能力在儿童期增加，在青年期达到高峰，然后下降。发展和衰老理论表明，儿童和老年人抑制控制过程的缺陷可能是导致其表现低于年轻人的原因。最近，脑电图（EEG）的振荡 alpha 功率（7-13 Hz）被认为是抑制过程的神经标志物，有助于 WM 表现（Sauseng 等人，2009）。我们在提示变化检测范式中检查了 20 名儿童（10-13 岁）、12 名年轻成年人（20-26 岁）和 20 名老年人（70-76 岁）。行为上，我们观察到年轻成年人在整个生命周期中的预期峰值。与儿童和年轻成年人相比，老年人的 EEG alpha 功率通常较低。与之前的研究一致，在保留间隔期间与注意力和 WM 过程相关的 alpha 功率的半球差异随着年轻成年人的负荷增加而增加。在儿童和老年人中，从低到中负荷条件下，偏侧化 alpha 功率增加，但在高负荷条件下减少。此外，与儿童和年轻成年人相比，老年人在刺激后不久显示出更高的试验间相位稳定性。我们的结果表明，抑制控制过程可以通过局部 alpha 功率调制来观察到，但是当 WM 负荷较高时，这种过程似乎会崩溃。此外，老年人对外界刺激的同步性更高，这可能会在后期处理中增加对抑制控制的需求。我们得出结论，抑制控制过程的差异以及振幅调制和 alpha 节律的试验间相位稳定性反映出的信息摄取，交互决定了整个生命周期的 WM 限制。
