Fischer Florian U, Wolf Dominik, Scheurich Armin, Fellgiebel Andreas
Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany.
PLoS One. 2014 Jan 22;9(1):e86258. doi: 10.1371/journal.pone.0086258. eCollection 2014.
Higher general intelligence attenuates age-associated cognitive decline and the risk of dementia. Thus, intelligence has been associated with cognitive reserve or resilience in normal aging. Neurophysiologically, intelligence is considered as a complex capacity that is dependent on a global cognitive network rather than isolated brain areas. An association of structural as well as functional brain network characteristics with intelligence has already been reported in young adults. We investigated the relationship between global structural brain network properties, general intelligence and age in a group of 43 cognitively healthy elderly, age 60-85 years. Individuals were assessed cross-sectionally using Wechsler Adult Intelligence Scale-Revised (WAIS-R) and diffusion-tensor imaging. Structural brain networks were reconstructed individually using deterministic tractography, global network properties (global efficiency, mean shortest path length, and clustering coefficient) were determined by graph theory and correlated to intelligence scores within both age groups. Network properties were significantly correlated to age, whereas no significant correlation to WAIS-R was observed. However, in a subgroup of 15 individuals aged 75 and above, the network properties were significantly correlated to WAIS-R. Our findings suggest that general intelligence and global properties of structural brain networks may not be generally associated in cognitively healthy elderly. However, we provide first evidence of an association between global structural brain network properties and general intelligence in advanced elderly. Intelligence might be affected by age-associated network deterioration only if a certain threshold of structural degeneration is exceeded. Thus, age-associated brain structural changes seem to be partially compensated by the network and the range of this compensation might be a surrogate of cognitive reserve or brain resilience.
较高的一般智力可减轻与年龄相关的认知衰退及患痴呆症的风险。因此，智力与正常衰老过程中的认知储备或恢复力相关。从神经生理学角度来看，智力被视为一种复杂的能力，它依赖于一个整体认知网络而非孤立的脑区。在年轻人中，已经报道了脑结构网络和功能网络特征与智力之间的关联。我们对一组43名年龄在60至85岁之间认知健康的老年人，研究了全脑结构网络属性、一般智力和年龄之间的关系。使用韦氏成人智力量表修订版（WAIS-R）和扩散张量成像对个体进行横断面评估。使用确定性纤维束成像分别重建脑结构网络，通过图论确定全局网络属性（全局效率、平均最短路径长度和聚类系数），并将其与两个年龄组内的智力得分相关联。网络属性与年龄显著相关，而与WAIS-R未观察到显著相关性。然而，在15名75岁及以上的亚组个体中，网络属性与WAIS-R显著相关。我们的研究结果表明，在认知健康的老年人中，一般智力和脑结构网络的全局属性可能通常不相关。然而，我们提供了首个证据，表明在高龄老年人中，脑结构网络全局属性与一般智力之间存在关联。只有当结构退化超过一定阈值时，智力才可能受到与年龄相关的网络退化的影响。因此，与年龄相关的脑结构变化似乎部分由网络得到补偿，这种补偿的范围可能是认知储备或脑恢复力的一个替代指标。
