Imagine your brain is a bustling city with different neighborhoods, each responsible for specialized functions. In the case of Alzheimer’s disease, one important neighborhood called the anterior cingulate cortex (ACC) goes through changes. Researchers conducted a study to understand how connections within different ACC sub-regions were affected in individuals with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI), which are early stages of Alzheimer’s disease. They discovered that both SCD and aMCI patients showed alterations in the functional connectivity of specific ACC sub-regions, such as increased connections between the PCUN and caudal ACC, left SFG and subgenual ACC, and many more. Interestingly, aMCI patients exhibited additional changes compared to SCD patients, including increased connectivity between the left IFG and dorsal ACC. These findings provide valuable insights into the early stages of Alzheimer’s disease and have the potential to be used as neuroimaging biomarkers for future preclinical interventions. To learn more about this fascinating research, check out the full article!

BackgroundSubjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) are considered part of the early progression continuum of Alzheimer’s disease (AD). The anterior cingulate cortex (ACC), a hub of information processing and regulation in the brain, plays an essential role in AD pathophysiology. In the present study, we aimed to systematically identify changes in the functional connectivity (FC) of ACC subregions in patients with SCD and aMCI and evaluate the association of these changes with cognition.Materials and methodsFunctional connectivity (FC) analysis of ACC sub-regions was performed among 66 patients with SCD, 71 patients with aMCI, and 78 healthy controls (HCs). Correlation analyses were performed to examine the relationship between FC of altered ACC subnetworks and cognition.ResultsCompared to HCs, SCD patients showed increased FC of the bilateral precuneus (PCUN) and caudal ACC, left superior frontal gyrus (SFG) and subgenual ACC, left inferior parietal lobule (IPL) and dorsal ACC, left middle occipital gyrus (MOG) and dorsal ACC, and left middle temporal gyrus (MTG) and subgenual ACC, while aMCI patients showed increased FC of the left inferior frontal gyrus (IFG) and dorsal ACC and left medial frontal gyrus (MFG) and subgenual ACC. Compared to patients with SCD, patients with aMCI showed increased FC of the right MFG and dorsal ACC and left ACC and subgenual ACC, while the left posterior cingulate cortex (PCC) showed decreased FC with the caudal ACC. Moreover, some FC values among the altered ACC subnetworks were significantly correlated with episodic memory and executive function.ConclusionSCD and aMCI, part of the spectrum of pre-clinical AD, share some convergent and divergent altered intrinsic connectivity of ACC subregions. These results may serve as neuroimaging biomarkers of the preclinical phase of AD and provide new insights into the design of preclinical interventions.

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