Max Planck Institute for Human Development, Berlin, Germany.
J Cogn Neurosci. 2011 Aug;23(8):2030-45. doi: 10.1162/jocn.2010.21560. Epub 2010 Sep 9.
Individual differences in working memory (WM) performance have rarely been related to individual differences in the functional responsivity of the WM brain network. By neglecting person-to-person variation, comparisons of network activity between younger and older adults using functional imaging techniques often confound differences in activity with age trends in WM performance. Using functional magnetic resonance imaging, we investigated the relations among WM performance, neural activity in the WM network, and adult age using a parametric letter n-back task in 30 younger adults (21-31 years) and 30 older adults (60-71 years). Individual differences in the WM network's responsivity to increasing task difficulty were related to WM performance, with a more responsive BOLD signal predicting greater WM proficiency. Furthermore, individuals with higher WM performance showed greater change in connectivity between left dorsolateral prefrontal cortex and left premotor cortex across load. We conclude that a more responsive WM network contributes to higher WM performance, regardless of adult age. Our results support the notion that individual differences in WM performance are important to consider when studying the WM network, particularly in age-comparative studies.
工作记忆（WM）表现的个体差异很少与 WM 大脑网络的功能反应性个体差异有关。通过忽略人与人之间的差异，使用功能成像技术比较年轻和老年人大脑网络的活动往往会将活动差异与 WM 表现的年龄趋势混淆。我们使用功能磁共振成像，在 30 名年轻成年人（21-31 岁）和 30 名老年成年人（60-71 岁）中使用参数化字母 n-back 任务，研究了 WM 表现、WM 网络中的神经活动和成人年龄之间的关系。WM 网络对增加任务难度的反应性的个体差异与 WM 表现有关，具有更高反应性的 BOLD 信号预示着更高的 WM 熟练程度。此外，WM 表现较高的个体在负载之间表现出左侧背外侧前额叶皮层和左侧运动前皮层之间连接性的更大变化。我们的结论是，无论成人年龄如何，更具反应性的 WM 网络有助于提高 WM 表现。我们的研究结果支持这样一种观点，即当研究 WM 网络时，特别是在年龄比较研究中，WM 表现的个体差异是需要考虑的重要因素。
