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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

Graph of networks built from mean absolute z-score matrices for HCs and SZ at threshold T = 0. 104. Red circles are nodes (voxels). Red lines are edges. Nodes are randomly organized but HCs and SZ have the same organization. Left: the left task-related network; Right: the right task-related network.
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FA1: Graph of networks built from mean absolute z-score matrices for HCs and SZ at threshold T = 0. 104. Red circles are nodes (voxels). Red lines are edges. Nodes are randomly organized but HCs and SZ have the same organization. Left: the left task-related network; Right: the right task-related network.

Mentions: The small-world attribute was evident in both left and right networks for both groups: γ was significantly greater than 1 while λ was near 1 over the whole range of T or K. Significant group differences were found in both left and right hemisphere networks. γ values and σ values were significantly decreased in SZ at all T and K values in the left network (Figure 5) and at most T and K values in the right network (Figure 6). See Figures A1,A2 for example graph (in form of nodes and edges) of 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)

Graph of networks built from mean absolute z-score matrices for HCs and SZ at threshold T = 0. 104. Red circles are nodes (voxels). Red lines are edges. Nodes are randomly organized but HCs and SZ have the same organization. Left: the left task-related network; Right: the right task-related network.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

FA1: Graph of networks built from mean absolute z-score matrices for HCs and SZ at threshold T = 0. 104. Red circles are nodes (voxels). Red lines are edges. Nodes are randomly organized but HCs and SZ have the same organization. Left: the left task-related network; Right: the right task-related network.
Mentions: The small-world attribute was evident in both left and right networks for both groups: γ was significantly greater than 1 while λ was near 1 over the whole range of T or K. Significant group differences were found in both left and right hemisphere networks. γ values and σ values were significantly decreased in SZ at all T and K values in the left network (Figure 5) and at most T and K values in the right network (Figure 6). See Figures A1,A2 for example graph (in form of nodes and edges) of 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