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Abnormal brain functional connectivity coupled with hypoperfusion measured by Resting-State fMRI: An additional
Bing Zhang1, Rui Hua2, Zhao Qing1
1Department of Radiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Abstract:
The contribution of hypoperfusion to abnormal functional connectivity in Alzheimer's disease (AD) and mild cognitive impairment (MCI) remains unclear. In this study, we investigated the potential association between brain perfusion and functional connectivity (FC), and its effects on the cognitive impairment among AD, MCI, and normal controls (NC). One-time acquisition of resting-state functional magnetic resonance imaging (rs-fMRI) was used to study brain perfusion and FC. Compared to the NC, the perfusion in the left temporal lobe showed significantly lower in AD, and bilateral hypoperfusion in the frontal lobe showed in MCI. Using these hypoperfusion areas as seed regions, we found that FC between the left inferior temporal gyrus and medial frontal-cingulate regions in AD patients was significantly lower than that in NCs. The FC between the right medial superior frontal gyrus and left parietal lobe in MCI patients was significantly higher than that in NCs. Additionally, the FC between the right medial superior frontal gyrus and the left superior parietal gyrus were found to be correlated significantly and negatively with mini-mental state examination (MMSE) scores in MCI patients. In conclusion, hypoperfusion may affect cognitive states via abnormal FC as an additional factor contributing to cognitive impairment.
Insights
Brain hypoperfusion is linked to altered functional connectivity (FC) in Alzheimer's disease (AD) and mild cognitive impairment (MCI). These changes in brain perfusion and FC may contribute to cognitive decline in these neurodegenerative conditions.
Area of Science:
- Neuroscience
- Medical Imaging
- Cognitive Neurology
Background:
- Alzheimer's disease (AD) and mild cognitive impairment (MCI) are associated with cognitive deficits.
- The role of cerebral hypoperfusion in abnormal functional connectivity (FC) in AD and MCI is not well understood.
Purpose of the Study:
- To investigate the association between brain perfusion and FC.
- To examine the impact of hypoperfusion-related FC changes on cognitive impairment in AD, MCI, and normal controls (NC).
Main Methods:
- Resting-state functional magnetic resonance imaging (rs-fMRI) was employed to assess brain perfusion and FC.
- Hypoperfusion areas were used as seed regions to analyze FC.
- Cognitive function was evaluated using the mini-mental state examination (MMSE).
Main Results:
- AD patients exhibited reduced perfusion in the left temporal lobe and lower FC between the left inferior temporal gyrus and medial frontal-cingulate regions compared to NCs.
- MCI patients showed bilateral frontal lobe hypoperfusion and increased FC between the right medial superior frontal gyrus and left parietal lobe.
- In MCI patients, altered FC correlated negatively with MMSE scores.
Conclusions:
- Hypoperfusion may influence cognitive status through abnormal FC.
- Altered brain perfusion and FC represent potential contributing factors to cognitive impairment in AD and MCI.