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Altered small-world brain networks in temporal lobe in patients with schizophrenia performing an auditory oddball task.

Yu Q, Sui J, Rachakonda S, He H, Pearlson G, Calhoun VD - Front Syst Neurosci (2011)

Bottom Line: The small-worldness values were decreased in both hemispheres in SZ.In addition, SZ showed longer shortest path length and lower global efficiency only in the left task-related networks.These results suggested small-world attributes are altered during the AOD task-related networks in SZ which provided further evidences for brain dysfunction of connectivity in SZ.

View Article: PubMed Central - PubMed

Affiliation: The Mind Research Network Albuquerque, NM, USA.

ABSTRACT
The functional architecture of the human brain has been extensively described in terms of complex networks characterized by efficient small-world features. Recent functional magnetic resonance imaging (fMRI) studies have found altered small-world topological properties of brain functional networks in patients with schizophrenia (SZ) during the resting state. However, little is known about the small-world properties of brain networks in the context of a task. In this study, we investigated the topological properties of human brain functional networks derived from fMRI during an auditory oddball (AOD) task. Data were obtained from 20 healthy controls and 20 SZ; A left and a right task-related network which consisted of the top activated voxels in temporal lobe of each hemisphere were analyzed separately. All voxels were detected by group independent component analysis. Connectivity of the left and right task-related networks were estimated by partial correlation analysis and thresholded to construct a set of undirected graphs. The small-worldness values were decreased in both hemispheres in SZ. In addition, SZ showed longer shortest path length and lower global efficiency only in the left task-related networks. These results suggested small-world attributes are altered during the AOD task-related networks in SZ which provided further evidences for brain dysfunction of connectivity in SZ.

No MeSH data available.


Related in: MedlinePlus

Mean shortest path length of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of threshold T (A), mean global efficiency (B) and shortest path length (C) of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of degree K. Error bars correspond to SEM (across 20 subjects of each group). Black triangles indicate where the group difference is significant (t-test, df = 38, 0.026 < P < 0.05, FDR correction for multiple comparisons).
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Figure 3: Mean shortest path length of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of threshold T (A), mean global efficiency (B) and shortest path length (C) of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of degree K. Error bars correspond to SEM (across 20 subjects of each group). Black triangles indicate where the group difference is significant (t-test, df = 38, 0.026 < P < 0.05, FDR correction for multiple comparisons).

Mentions: When looking at the topological indices as a function of threshold T, in both left and right task-related networks, the higher threshold resulted in a lower clustering coefficient, lower local efficiency, lower global efficiency, lower degree, and higher shortest path length because more and more edges were being lost with an increase in the threshold. Two-sample t-tests (FDR correction for multiple comparisons) indicated only shortest path length had significant group differences in the left task-related networks. As shown in Figure 3A, SZ had higher shortest path length at higher threshold points (0.098–0.110). Effect size (Cohen, 1988; Hartung et al., 2008) of shortest path length at threshold 0.104 was 0.9619. No group difference was found in the right task-related networks.


Altered small-world brain networks in temporal lobe in patients with schizophrenia performing an auditory oddball task.

Yu Q, Sui J, Rachakonda S, He H, Pearlson G, Calhoun VD - Front Syst Neurosci (2011)

Mean shortest path length of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of threshold T (A), mean global efficiency (B) and shortest path length (C) of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of degree K. Error bars correspond to SEM (across 20 subjects of each group). Black triangles indicate where the group difference is significant (t-test, df = 38, 0.026 < P < 0.05, FDR correction for multiple comparisons).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3037777&req=5

Figure 3: Mean shortest path length of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of threshold T (A), mean global efficiency (B) and shortest path length (C) of the left task-related networks for HCs (blue circles) and SZ (red squares) as a function of degree K. Error bars correspond to SEM (across 20 subjects of each group). Black triangles indicate where the group difference is significant (t-test, df = 38, 0.026 < P < 0.05, FDR correction for multiple comparisons).
Mentions: When looking at the topological indices as a function of threshold T, in both left and right task-related networks, the higher threshold resulted in a lower clustering coefficient, lower local efficiency, lower global efficiency, lower degree, and higher shortest path length because more and more edges were being lost with an increase in the threshold. Two-sample t-tests (FDR correction for multiple comparisons) indicated only shortest path length had significant group differences in the left task-related networks. As shown in Figure 3A, SZ had higher shortest path length at higher threshold points (0.098–0.110). Effect size (Cohen, 1988; Hartung et al., 2008) of shortest path length at threshold 0.104 was 0.9619. No group difference was found in the right task-related networks.

Bottom Line: The small-worldness values were decreased in both hemispheres in SZ.In addition, SZ showed longer shortest path length and lower global efficiency only in the left task-related networks.These results suggested small-world attributes are altered during the AOD task-related networks in SZ which provided further evidences for brain dysfunction of connectivity in SZ.

View Article: PubMed Central - PubMed

Affiliation: The Mind Research Network Albuquerque, NM, USA.

ABSTRACT
The functional architecture of the human brain has been extensively described in terms of complex networks characterized by efficient small-world features. Recent functional magnetic resonance imaging (fMRI) studies have found altered small-world topological properties of brain functional networks in patients with schizophrenia (SZ) during the resting state. However, little is known about the small-world properties of brain networks in the context of a task. In this study, we investigated the topological properties of human brain functional networks derived from fMRI during an auditory oddball (AOD) task. Data were obtained from 20 healthy controls and 20 SZ; A left and a right task-related network which consisted of the top activated voxels in temporal lobe of each hemisphere were analyzed separately. All voxels were detected by group independent component analysis. Connectivity of the left and right task-related networks were estimated by partial correlation analysis and thresholded to construct a set of undirected graphs. The small-worldness values were decreased in both hemispheres in SZ. In addition, SZ showed longer shortest path length and lower global efficiency only in the left task-related networks. These results suggested small-world attributes are altered during the AOD task-related networks in SZ which provided further evidences for brain dysfunction of connectivity in SZ.

No MeSH data available.


Related in: MedlinePlus