Braaß Hanna, Reiter Nadine, Backhaus Winifried, Wróbel Paweł P, Quandt Fanny, Schulz Robert, Gerloff Christian, Higgen Focko L
Department of Neurology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
Department of Systems Neuroscience, University Medical Center Hamburg- Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
Sci Rep. 2025 Sep 12;15(1):32489. doi: 10.1038/s41598-025-19143-y.
Cognitive aging is a heterogeneous process characterized by a varied decline in brain performance. While the neurophysiological basis of this decline remains poorly understood, age-related alterations in structural connectivity (SC) and functional connectivity (FC) have been implicated. Understanding the relationship between these changes is crucial for identifying early markers of cognitive impairment. In our previous work, we observed that in healthy older adults, diminished performance in a tactile recognition task was associated with reduced fractional anisotropy (FA) in the anterior corpus callosum (aCC). The aim of this study was to investigate the impact of this age-related SC degeneration on the FC between the connected regions. In the current analysis, we examined resting-state functional MRI data from 29 healthy older adults, who were categorized into two subgroups - high and low performers - based on their performance in a tactile recognition task and a younger control group (N = 20). We conducted a region of interest (ROI) to ROI analysis to evaluate FC between frontal regions connected via the aCC. Subsequently, we compared the FC between the groups and assessed its correlation with FA values in the aCC across all older participants based on a TBSS analysis from our previous work. We found that poorer performance in a tactile recognition task was associated with increased FC between frontal regions. The second main finding was a negative correlation between FA in the aCC and FC between frontal regions. Our findings suggest that structural degradation of the underlying pathways may initially lead to increased FC within the connected regions, possibly as a compensatory mechanism to preserve cognitive function. However, as no direct brain-behavior correlation was assessed, this interpretation remains tentative. The aCC appears to be particularly vulnerable to age-related structural decline, which may underlie functional changes in frontal regions observed with aging.
认知老化是一个异质性过程，其特征是大脑功能出现不同程度的衰退。虽然这种衰退的神经生理基础仍知之甚少，但结构连接性（SC）和功能连接性（FC）的年龄相关变化已被认为与之有关。了解这些变化之间的关系对于识别认知障碍的早期标志物至关重要。在我们之前的研究中，我们观察到在健康的老年人中，触觉识别任务表现的下降与胼胝体前部（aCC）的分数各向异性（FA）降低有关。本研究的目的是调查这种与年龄相关的SC退化对相连区域之间FC的影响。在当前的分析中，我们检查了29名健康老年人的静息态功能磁共振成像数据，这些老年人根据他们在触觉识别任务中的表现被分为两个亚组——高表现者和低表现者——以及一个年轻对照组（N = 20）。我们进行了感兴趣区域（ROI）到ROI的分析，以评估通过aCC相连的额叶区域之间的FC。随后，我们比较了各组之间的FC，并根据我们之前工作中的基于体素的全脑空间统计分析（TBSS）评估了其与所有老年参与者aCC中FA值的相关性。我们发现触觉识别任务中较差的表现与额叶区域之间FC的增加有关。第二个主要发现是aCC中的FA与额叶区域之间的FC呈负相关。我们的研究结果表明，潜在通路的结构退化可能最初会导致相连区域内FC增加，这可能是一种保留认知功能的补偿机制。然而，由于未评估直接的脑-行为相关性，这种解释仍然是初步的。aCC似乎特别容易受到与年龄相关的结构衰退的影响，这可能是衰老过程中额叶区域功能变化的基础。
