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Frequency-specific alterations of large-scale functional brain networks in patients with Alzheimer's disease.

Qin YY, Li YP, Zhang S, Xiong Y, Guo LY, Yang SQ, Yao YH, Li W, Zhu WZ - Chin. Med. J. (2015)

Bottom Line: At lower-frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz), the global efficiency, the CC and the "small-world" properties of AD patients decreased compared to controls.The topological properties changed with different frequency bands, suggesting the existence of disrupted global and local functional organization associated with AD.This study demonstrates that the topological alterations of large-scale functional brain networks in AD patients are frequency dependent, thus providing fundamental support for optimal frequency selection in future related research.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.

ABSTRACT

Background: Previous studies have indicated that the cognitive deficits in patients with Alzheimer's disease (AD) may be due to topological deteriorations of the brain network. However, whether the selection of a specific frequency band could impact the topological properties is still not clear. Our hypothesis is that the topological properties of AD patients are also frequency-specific.

Methods: Resting state functional magnetic resonance imaging data from 10 right-handed moderate AD patients (mean age: 64.3 years; mean mini mental state examination [MMSE]: 18.0) and 10 age and gender-matched healthy controls (mean age: 63.6 years; mean MMSE: 28.2) were enrolled in this study. The global efficiency, the clustering coefficient (CC), the characteristic path length (CpL), and "small-world" property were calculated in a wide range of thresholds and averaged within each group, at three different frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz, and 0.11-0.25 Hz).

Results: At lower-frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz), the global efficiency, the CC and the "small-world" properties of AD patients decreased compared to controls. While at higher-frequency bands (0.11-0.25 Hz), the CpL was much longer, and the "small-world" property was disrupted in AD, particularly at a higher threshold. The topological properties changed with different frequency bands, suggesting the existence of disrupted global and local functional organization associated with AD.

Conclusions: This study demonstrates that the topological alterations of large-scale functional brain networks in AD patients are frequency dependent, thus providing fundamental support for optimal frequency selection in future related research.

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Related in: MedlinePlus

The global efficiencies of the functional brain networks in Alzheimer's disease patients (marked in black) and in healthy controls (marked in red) at the three different frequency bands.
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Figure 1: The global efficiencies of the functional brain networks in Alzheimer's disease patients (marked in black) and in healthy controls (marked in red) at the three different frequency bands.

Mentions: The global efficiencies of AD patients and healthy controls at three different frequency bands are shown in Figure 1. The global efficiencies of AD patients were always lower than healthy controls at the frequency bands of 0.01–0.06 Hz and 0.06–0.11 Hz under all thresholds. No significant difference of global efficiency between groups at the frequency band of 0.11–0.25 Hz was found at smaller thresholds. However, within a higher threshold (more than 0.5), the global efficiency was still lower in AD patients than in healthy controls.


Frequency-specific alterations of large-scale functional brain networks in patients with Alzheimer's disease.

Qin YY, Li YP, Zhang S, Xiong Y, Guo LY, Yang SQ, Yao YH, Li W, Zhu WZ - Chin. Med. J. (2015)

The global efficiencies of the functional brain networks in Alzheimer's disease patients (marked in black) and in healthy controls (marked in red) at the three different frequency bands.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834769&req=5

Figure 1: The global efficiencies of the functional brain networks in Alzheimer's disease patients (marked in black) and in healthy controls (marked in red) at the three different frequency bands.
Mentions: The global efficiencies of AD patients and healthy controls at three different frequency bands are shown in Figure 1. The global efficiencies of AD patients were always lower than healthy controls at the frequency bands of 0.01–0.06 Hz and 0.06–0.11 Hz under all thresholds. No significant difference of global efficiency between groups at the frequency band of 0.11–0.25 Hz was found at smaller thresholds. However, within a higher threshold (more than 0.5), the global efficiency was still lower in AD patients than in healthy controls.

Bottom Line: At lower-frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz), the global efficiency, the CC and the "small-world" properties of AD patients decreased compared to controls.The topological properties changed with different frequency bands, suggesting the existence of disrupted global and local functional organization associated with AD.This study demonstrates that the topological alterations of large-scale functional brain networks in AD patients are frequency dependent, thus providing fundamental support for optimal frequency selection in future related research.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.

ABSTRACT

Background: Previous studies have indicated that the cognitive deficits in patients with Alzheimer's disease (AD) may be due to topological deteriorations of the brain network. However, whether the selection of a specific frequency band could impact the topological properties is still not clear. Our hypothesis is that the topological properties of AD patients are also frequency-specific.

Methods: Resting state functional magnetic resonance imaging data from 10 right-handed moderate AD patients (mean age: 64.3 years; mean mini mental state examination [MMSE]: 18.0) and 10 age and gender-matched healthy controls (mean age: 63.6 years; mean MMSE: 28.2) were enrolled in this study. The global efficiency, the clustering coefficient (CC), the characteristic path length (CpL), and "small-world" property were calculated in a wide range of thresholds and averaged within each group, at three different frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz, and 0.11-0.25 Hz).

Results: At lower-frequency bands (0.01-0.06 Hz, 0.06-0.11 Hz), the global efficiency, the CC and the "small-world" properties of AD patients decreased compared to controls. While at higher-frequency bands (0.11-0.25 Hz), the CpL was much longer, and the "small-world" property was disrupted in AD, particularly at a higher threshold. The topological properties changed with different frequency bands, suggesting the existence of disrupted global and local functional organization associated with AD.

Conclusions: This study demonstrates that the topological alterations of large-scale functional brain networks in AD patients are frequency dependent, thus providing fundamental support for optimal frequency selection in future related research.

Show MeSH
Related in: MedlinePlus