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Disconnection of the hippocampus and amygdala associated with lesion load in relapsing-remitting multiple sclerosis: a structural and functional connectivity study.

Zhou F, Zhuang Y, Wang L, Zhang Y, Wu L, Zeng X, Gong H - Neuropsychiatr Dis Treat (2015)

Bottom Line: Compared with healthy subjects, the RRMS patients showed significantly decreased SC and increased FCS of the bilateral hippocampus, and left amygdala.A relationship between WM lesion load and FCS of the left amygdale was also observed.The concurrent increased functional connections and demyelination-related structural disconnectivity between the hippocampus or amygdala and other regions in RRMS suggest that the functional-structural relationships require further investigation.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China.

ABSTRACT

Background and purpose: Little is known about the functional and structural connectivity (FC and SC) of the hippocampus and amygdala, which are two important structures involved in cognitive processes, or their involvement in relapsing-remitting multiple sclerosis (RRMS). In this study, we aimed to examine the connectivity of white-matter (WM) tracts and the synchrony of intrinsic neuronal activity in outer regions connected with the hippocampus or amygdala in RRMS patients.

Patients and methods: Twenty-three RRMS patients and 23 healthy subjects participated in this study. Diffusion tensor probabilistic tractography was used to examine the SC, the FC correlation coefficient (FC-CC) and combined FC strength (FCS), which was derived from the resting-state functional magnetic resonance imaging used to examine the FC, of the connection between the hippocampus or the amygdala and other regions, and the correlations of these connections with clinical markers.

Results: Compared with healthy subjects, the RRMS patients showed significantly decreased SC and increased FCS of the bilateral hippocampus, and left amygdala. Their slightly increased FC-CC was positively correlated with WM tract damage in the right hippocampus (ρ=0.57, P=0.005); an increased FCS was also positively correlated with WM tract damage in the right amygdala. A relationship was observed between the WM lesion load and SC alterations, including the lg(N tracts) of the right hippocampus (ρ=-0.68, P<0.05), lg(N tracts) (ρ=-0.69, P<0.05), and fractional anisotropy (ρ=-0.68, P<0.05) and radial diffusivity of the left hippocampus (ρ=0.45, P<0.05). A relationship between WM lesion load and FCS of the left amygdale was also observed.

Conclusion: The concurrent increased functional connections and demyelination-related structural disconnectivity between the hippocampus or amygdala and other regions in RRMS suggest that the functional-structural relationships require further investigation.

No MeSH data available.


Related in: MedlinePlus

A set of connectivity matrices of functional and structural analyses of the amygdala and hippocampus in the RRMS and healthy control (HC) groups.Notes: The panels (A and B) are a histogram of average FC-CC or FCS in the amygdala and hippocampus. The panels (C and D) show the structural connectivity strength (of average lg[N tracts] and volumes) of the amygdala and hippocampus. The panels (E–H) are above-threshold (0.2) standard DTI parameters, including the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of each fiber tract. The error bars are the standard errors of the mean. *P<0.05, **P<0.01, ***P<0.001.Abbreviations: amyg, amygdala; DTI, diffusion tensor imaging; FC-CC, functional connectivity correlation coefficient; FCS, functional connectivity strength; hipp, hippocampus; MS, multiple sclerosis; RRMS, relapsing–remitting multiple sclerosis; SC, structural connectivity.
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f2-ndt-11-1749: A set of connectivity matrices of functional and structural analyses of the amygdala and hippocampus in the RRMS and healthy control (HC) groups.Notes: The panels (A and B) are a histogram of average FC-CC or FCS in the amygdala and hippocampus. The panels (C and D) show the structural connectivity strength (of average lg[N tracts] and volumes) of the amygdala and hippocampus. The panels (E–H) are above-threshold (0.2) standard DTI parameters, including the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of each fiber tract. The error bars are the standard errors of the mean. *P<0.05, **P<0.01, ***P<0.001.Abbreviations: amyg, amygdala; DTI, diffusion tensor imaging; FC-CC, functional connectivity correlation coefficient; FCS, functional connectivity strength; hipp, hippocampus; MS, multiple sclerosis; RRMS, relapsing–remitting multiple sclerosis; SC, structural connectivity.

Mentions: Seed-based FC was then used to measure the FC-CC between the positively correlated regions and the seed region (amygdala or hippocampus). The results of a one-sample t-test found similar FC-CC distributions of the amygdala and hippocampus in the RRMS and HC groups (false-discovery rate corrected, P<0.01) (Figure S1). In a cluster-based analysis, a significant FC-CC difference was not detected between the RRMS and HC groups (P>0.05) (Table S1, Figure 2A). However, in a voxel-based GLM analysis, compared with HCs, significantly reduced FC-CCs (including bilateral putamen, detailed results shown in Table S2 and Figure S2) were only detected in the RRMS group (P<0.05, Gaussian random field theory corrected, minimum z>2.3).


Disconnection of the hippocampus and amygdala associated with lesion load in relapsing-remitting multiple sclerosis: a structural and functional connectivity study.

Zhou F, Zhuang Y, Wang L, Zhang Y, Wu L, Zeng X, Gong H - Neuropsychiatr Dis Treat (2015)

A set of connectivity matrices of functional and structural analyses of the amygdala and hippocampus in the RRMS and healthy control (HC) groups.Notes: The panels (A and B) are a histogram of average FC-CC or FCS in the amygdala and hippocampus. The panels (C and D) show the structural connectivity strength (of average lg[N tracts] and volumes) of the amygdala and hippocampus. The panels (E–H) are above-threshold (0.2) standard DTI parameters, including the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of each fiber tract. The error bars are the standard errors of the mean. *P<0.05, **P<0.01, ***P<0.001.Abbreviations: amyg, amygdala; DTI, diffusion tensor imaging; FC-CC, functional connectivity correlation coefficient; FCS, functional connectivity strength; hipp, hippocampus; MS, multiple sclerosis; RRMS, relapsing–remitting multiple sclerosis; SC, structural connectivity.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4514382&req=5

f2-ndt-11-1749: A set of connectivity matrices of functional and structural analyses of the amygdala and hippocampus in the RRMS and healthy control (HC) groups.Notes: The panels (A and B) are a histogram of average FC-CC or FCS in the amygdala and hippocampus. The panels (C and D) show the structural connectivity strength (of average lg[N tracts] and volumes) of the amygdala and hippocampus. The panels (E–H) are above-threshold (0.2) standard DTI parameters, including the fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of each fiber tract. The error bars are the standard errors of the mean. *P<0.05, **P<0.01, ***P<0.001.Abbreviations: amyg, amygdala; DTI, diffusion tensor imaging; FC-CC, functional connectivity correlation coefficient; FCS, functional connectivity strength; hipp, hippocampus; MS, multiple sclerosis; RRMS, relapsing–remitting multiple sclerosis; SC, structural connectivity.
Mentions: Seed-based FC was then used to measure the FC-CC between the positively correlated regions and the seed region (amygdala or hippocampus). The results of a one-sample t-test found similar FC-CC distributions of the amygdala and hippocampus in the RRMS and HC groups (false-discovery rate corrected, P<0.01) (Figure S1). In a cluster-based analysis, a significant FC-CC difference was not detected between the RRMS and HC groups (P>0.05) (Table S1, Figure 2A). However, in a voxel-based GLM analysis, compared with HCs, significantly reduced FC-CCs (including bilateral putamen, detailed results shown in Table S2 and Figure S2) were only detected in the RRMS group (P<0.05, Gaussian random field theory corrected, minimum z>2.3).

Bottom Line: Compared with healthy subjects, the RRMS patients showed significantly decreased SC and increased FCS of the bilateral hippocampus, and left amygdala.A relationship between WM lesion load and FCS of the left amygdale was also observed.The concurrent increased functional connections and demyelination-related structural disconnectivity between the hippocampus or amygdala and other regions in RRMS suggest that the functional-structural relationships require further investigation.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, People's Republic of China ; Jiangxi Province Medical Imaging Research Institute, Jiangxi Province, People's Republic of China.

ABSTRACT

Background and purpose: Little is known about the functional and structural connectivity (FC and SC) of the hippocampus and amygdala, which are two important structures involved in cognitive processes, or their involvement in relapsing-remitting multiple sclerosis (RRMS). In this study, we aimed to examine the connectivity of white-matter (WM) tracts and the synchrony of intrinsic neuronal activity in outer regions connected with the hippocampus or amygdala in RRMS patients.

Patients and methods: Twenty-three RRMS patients and 23 healthy subjects participated in this study. Diffusion tensor probabilistic tractography was used to examine the SC, the FC correlation coefficient (FC-CC) and combined FC strength (FCS), which was derived from the resting-state functional magnetic resonance imaging used to examine the FC, of the connection between the hippocampus or the amygdala and other regions, and the correlations of these connections with clinical markers.

Results: Compared with healthy subjects, the RRMS patients showed significantly decreased SC and increased FCS of the bilateral hippocampus, and left amygdala. Their slightly increased FC-CC was positively correlated with WM tract damage in the right hippocampus (ρ=0.57, P=0.005); an increased FCS was also positively correlated with WM tract damage in the right amygdala. A relationship was observed between the WM lesion load and SC alterations, including the lg(N tracts) of the right hippocampus (ρ=-0.68, P<0.05), lg(N tracts) (ρ=-0.69, P<0.05), and fractional anisotropy (ρ=-0.68, P<0.05) and radial diffusivity of the left hippocampus (ρ=0.45, P<0.05). A relationship between WM lesion load and FCS of the left amygdale was also observed.

Conclusion: The concurrent increased functional connections and demyelination-related structural disconnectivity between the hippocampus or amygdala and other regions in RRMS suggest that the functional-structural relationships require further investigation.

No MeSH data available.


Related in: MedlinePlus