Bauer Eva, Sammer Gebhard, Toepper Max
Cognitive Neuroscience at the Centre for Psychiatry, University of Giessen, Am Steg 24, 35385 Giessen, Germany.
Cognitive Neuroscience at the Centre for Psychiatry, University of Giessen, Am Steg 24, 35385 Giessen, Germany ; Department of Psychology, University of Giessen, Otto-Behaghel-Straße 10, 35394 Giessen, Germany ; Bender Institute of Neuroimaging, University of Giessen, Otto-Behaghel-Straße 10H, 35394 Giessen, Germany.
Biomed Res Int. 2015;2015:415458. doi: 10.1155/2015/415458. Epub 2015 Oct 8.
Age-related working memory decline is associated with functional cerebral changes within prefrontal cortex (PFC). Kind and meaning of these changes are heavily discussed since they depend on performance level and task load. Hence, we investigated the effects of age, performance level, and load on spatial working memory retrieval-related brain activation in different subregions of the PFC. 19 younger (Y) and 21 older (O) adults who were further subdivided into high performers (HP) and low performers (LP) performed a modified version of the Corsi Block-Tapping test during fMRI. Brain data was analyzed by a 4 (groups: YHP, OHP, YLP, and OLP) × 3 (load levels: loads 4, 5, and 6) ANOVA. Results revealed significant group × load interaction effects within rostral dorsolateral and ventrolateral PFC. YHP showed a flexible neural upregulation with increasing load, whereas YLP reached a resource ceiling at a moderate load level. OHP showed a similar (though less intense) pattern as YHP and may have compensated age-effects at high task load. OLP showed neural inefficiency at low and no upregulation at higher load. Our findings highlight the relevance of age and performance level for load-dependent activation within rostral PFC. Results are discussed in the context of the compensation-related utilization of neural circuits hypothesis (CRUNCH) and functional PFC organization.
与年龄相关的工作记忆衰退与前额叶皮层（PFC）内的大脑功能变化有关。由于这些变化的性质和意义取决于表现水平和任务负荷，因此一直备受讨论。因此，我们研究了年龄、表现水平和负荷对PFC不同亚区域中与空间工作记忆检索相关的大脑激活的影响。19名年轻（Y）成年人和21名年长（O）成年人，他们又被进一步细分为高表现者（HP）和低表现者（LP），在功能磁共振成像（fMRI）期间进行了改良版的Corsi方块敲击测试。通过4（组：YHP、OHP、YLP和OLP）×3（负荷水平：负荷4、5和6）方差分析对脑数据进行分析。结果显示，在腹侧背外侧和腹外侧PFC内存在显著的组×负荷交互作用。YHP随着负荷增加表现出灵活的神经上调，而YLP在中等负荷水平时达到资源上限。OHP表现出与YHP相似（尽管程度较轻）的模式，并且可能在高任务负荷时补偿了年龄效应。OLP在低负荷时表现出神经效率低下，在高负荷时没有上调。我们的研究结果突出了年龄和表现水平对腹侧PFC内负荷依赖性激活的相关性。在神经回路假说（CRUNCH）和功能性PFC组织的背景下对结果进行了讨论。
