Bozzali Marco, Dowling Claire, Serra Laura, Spanò Barbara, Torso Mario, Marra Camillo, Castelli Diana, Dowell Nicholas G, Koch Giacomo, Caltagirone Carlo, Cercignani Mara
Neuroimaging Laboratory, IRCSS Santa Lucia, Rome, Italy.
School of Life Sciences, University of Sussex, Brighton, United Kingdom.
J Alzheimers Dis. 2015;44(1):243-50. doi: 10.3233/JAD-141824.
One factor believed to impact brain resilience to the pathological damage of Alzheimer's disease (AD) is the so-called "cognitive reserve" (CR). A critical issue that still needs to be fully understood is the mechanism by which environmental enrichment interacts with brain plasticity to determine resilience to AD pathology. Previous work using PET suggests that increased brain connectivity might be at the origin of the compensatory mechanisms implicated in this process. This study aims to further clarify this issue using resting-state functional MRI. Resting-state functional MRI was collected for 11 patients with AD, 18 with mild cognitive impairment (MCI), and 16 healthy controls, and analyzed to isolate the default mode network (DMN). A quantitative score of CR was obtained by combining information about number of years of education and type of schools attended. Consistent with previous reports, education was found to modulate functional connectivity in the posterior cingulate cortex, whose disconnection with the temporal lobes is known to be critical for the conversion from MCI to AD. This effect was highly significant in AD patients, less so in patients with MCI, and absent in healthy subjects. These findings show the potential neural mechanisms underlying the individual's ability to cope with brain damage, although they should be treated with some caution based on small numbers.
一种被认为会影响大脑对阿尔茨海默病（AD）病理损伤恢复力的因素是所谓的“认知储备”（CR）。一个仍需充分理解的关键问题是环境丰富化与大脑可塑性相互作用以决定对AD病理恢复力的机制。先前使用正电子发射断层扫描（PET）的研究表明，大脑连接性增加可能是这一过程中涉及的补偿机制的根源。本研究旨在使用静息态功能磁共振成像（MRI）进一步阐明这一问题。对11名AD患者、18名轻度认知障碍（MCI）患者和16名健康对照者进行了静息态功能MRI扫描，并进行分析以分离默认模式网络（DMN）。通过结合受教育年限和就读学校类型的信息获得了CR的定量评分。与先前的报告一致，发现教育可调节后扣带回皮质的功能连接，已知其与颞叶的断开连接对从MCI转变为AD至关重要。这种效应在AD患者中非常显著，在MCI患者中较小，而在健康受试者中不存在。这些发现揭示了个体应对脑损伤能力背后的潜在神经机制，尽管基于样本量小的原因，这些发现应谨慎对待。
