Maximal aerobic capacity (MAC) has been associated with preserved neural tissue or brain maintenance (BM) in healthy older adults, including the hippocampus. Amnestic mild cognitive impairment (aMCI) is considered a prodromal stage of Alzheimer's disease. While aMCI is characterized by hippocampal deterioration, the MAC‐hippocampal relationship in these patients is not well understood. In contrast to healthy individuals, neurocognitive protective effects in neurodegenerative populations have been associated with mechanisms of cognitive reserve (CR) altering the neuropathology‐cognition relationship. We investigated the MAC‐hippocampal relationship in aMCI (n = 29) from the perspectives of BM and CR mechanistic models with structural MRI and a memory fMRI paradigm using both group‐level (higher‐fit patients vs. lower‐fit patients) and individual level (continuous correlation) approaches. While MAC was associated with smaller hippocampal volume, contradicting the BM model, higher‐fit patients demonstrated statistically significant lower correlation between hippocampal volume and memory performance compared with the lower‐fit patients, supporting the model of CR. In addition, while there was no difference in brain activity between the groups during low cognitive demand (encoding of familiar stimuli), higher MAC level was associated with increased cortical and sub‐cortical activation during increased cognitive demand (encoding of novel stimuli) and also with bilateral hippocampal activity even when controlling for hippocampal volume, suggesting for an independent effect of MAC. Our results suggest that MAC may be associated with hippocampal‐related cognitive reserve in aMCI through altering the relationship between hippocampal‐related structural deterioration and cognitive function. In addition, MAC was found to be associated with increased capacity to recruit neural resources during increased cognitive demands.

中文翻译：

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遗忘型轻度认知障碍老年人的最大有氧能力与海马认知储备有关

最大有氧能力（MAC）与健康老年人（包括海马）的神经组织或大脑维持（BM）有关。遗忘性轻度认知障碍 (aMCI) 被认为是阿尔茨海默病的前驱阶段。虽然 aMCI 的特征是海马退化，但这些患者的 MAC-海马关系尚不清楚。与健康个体相比，神经退行性人群中的神经认知保护作用与改变神经病理学 - 认知关系的认知储备 (CR) 机制有关。我们研究了 aMCI ( n= 29）从结构 MRI 和记忆 fMRI 范式的 BM 和 CR 机制模型的角度来看，使用组级（高拟合患者与低拟合患者）和个体水平（连续相关）方法。虽然 MAC 与较小的海马体积相关，与 BM 模型相矛盾，但与低拟合患者相比，高拟合患者的海马体积与记忆能力之间的相关性显着降低，这支持了 CR 模型。此外，虽然在低认知需求（熟悉刺激的编码）期间，各组之间的大脑活动没有差异，较高的 MAC 水平与增加的认知需求（编码新刺激）期间的皮质和皮质下激活增加有关，即使在控制海马体积时也与双侧海马活动相关，这表明 MAC 的独立作用。我们的研究结果表明，MAC 可能通过改变海马相关结构恶化与认知功能之间的关系与 aMCI 中海马相关的认知储备相关。此外，发现 MAC 与增加认知需求期间募集神经资源的能力有关。我们的研究结果表明，MAC 可能通过改变海马相关结构恶化与认知功能之间的关系与 aMCI 中海马相关的认知储备相关。此外，发现 MAC 与增加认知需求期间募集神经资源的能力有关。我们的研究结果表明，MAC 可能通过改变海马相关结构恶化与认知功能之间的关系与 aMCI 中海马相关的认知储备相关。此外，发现 MAC 与增加认知需求期间募集神经资源的能力有关。