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Reconfiguration of the Brain Functional Network Associated with Visual Task Demands.

Wen X, Zhang D, Liang B, Zhang R, Wang Z, Wang J, Liu M, Huang R - PLoS ONE (2015)

Bottom Line: Compared with the resting-state, the functional networks associated with the visual tasks exhibited significantly increased network efficiency and wiring-cost, but decreased modularity and network robustness.Moreover, at the regional level, we observed that the increased nodal efficiencies in the visual and working memory regions were positively associated with the increase in task complexity.Together, these results suggest that the increased efficiency of the functional brain network and higher wiring-cost were observed to afford the demands of visual tasks.

View Article: PubMed Central - PubMed

Affiliation: Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China.

ABSTRACT
Neuroimaging studies have demonstrated that the topological properties of resting-state brain functional networks are modulated through task performances. However, the reconfiguration of functional networks associated with distinct degrees of task demands is not well understood. In the present study, we acquired fMRI data from 18 healthy adult volunteers during resting-state (RS) and two visual tasks (i.e., visual stimulus watching, VSW; and visual stimulus decision, VSD). Subsequently, we constructed the functional brain networks associated with these three conditions and analyzed the changes in the topological properties (e.g., network efficiency, wiring-cost, modularity, and robustness) among them. Although the small-world attributes were preserved qualitatively across the functional networks of the three conditions, changes in the topological properties were also observed. Compared with the resting-state, the functional networks associated with the visual tasks exhibited significantly increased network efficiency and wiring-cost, but decreased modularity and network robustness. The changes in the task-related topological properties were modulated according to the task complexity (i.e., from RS to VSW and VSD). Moreover, at the regional level, we observed that the increased nodal efficiencies in the visual and working memory regions were positively associated with the increase in task complexity. Together, these results suggest that the increased efficiency of the functional brain network and higher wiring-cost were observed to afford the demands of visual tasks. These observations provide further insights into the mechanisms underlying the reconfiguration of the brain network during task performance.

No MeSH data available.


Related in: MedlinePlus

Global parameters of brain functional networks across all subjects in the three cognitive conditions.(Top row) Within-subject effects of task complexity on the clustering coefficient Cp, characteristic path length Lp, local efficiency Eloc, global efficiency Eglob. (Bottom row) Box-plots show the median, interquartile range, and range for each parameter in each condition. Each horizontal line and the associated number indicate the p-value of a post-hoc paired t-test (two-tailed). RS: resting-state, VSW: visual stimulus watching task, VSD: visual stimulus decision task.
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pone.0132518.g002: Global parameters of brain functional networks across all subjects in the three cognitive conditions.(Top row) Within-subject effects of task complexity on the clustering coefficient Cp, characteristic path length Lp, local efficiency Eloc, global efficiency Eglob. (Bottom row) Box-plots show the median, interquartile range, and range for each parameter in each condition. Each horizontal line and the associated number indicate the p-value of a post-hoc paired t-test (two-tailed). RS: resting-state, VSW: visual stimulus watching task, VSD: visual stimulus decision task.

Mentions: Despite the small-world architecture in these brain functional networks, significant differences in the network topological properties were observed. ANOVA revealed significant main effects of task demands on all eight network global parameters across the three cognitive conditions (Table 1). In addition, post-hoc comparisons showed that Cp, Eloc and Eglob monotonously increased and Lp decreased in response to the task demands ranging from RS to VSW, and then to VSD (Fig 2). This result suggested that the greater the visual task complexity, the more efficient the network, but with less small-worldness. Fig 2 also shows the individual within-subject effect of task demands on these parameters. In addition, the wiring-costs described by K and Dp, both monotonously increased from RS to VSW, and then to VSD (Fig 3A), suggesting that the brain functional network simultaneously sacrifices a certain cost to meet the demands of complex tasks. Moreover, we observed that the greater the visual task complexity, the less modularity (i.e., decrease of Q) in the functional networks (Fig 3B).


Reconfiguration of the Brain Functional Network Associated with Visual Task Demands.

Wen X, Zhang D, Liang B, Zhang R, Wang Z, Wang J, Liu M, Huang R - PLoS ONE (2015)

Global parameters of brain functional networks across all subjects in the three cognitive conditions.(Top row) Within-subject effects of task complexity on the clustering coefficient Cp, characteristic path length Lp, local efficiency Eloc, global efficiency Eglob. (Bottom row) Box-plots show the median, interquartile range, and range for each parameter in each condition. Each horizontal line and the associated number indicate the p-value of a post-hoc paired t-test (two-tailed). RS: resting-state, VSW: visual stimulus watching task, VSD: visual stimulus decision task.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493060&req=5

pone.0132518.g002: Global parameters of brain functional networks across all subjects in the three cognitive conditions.(Top row) Within-subject effects of task complexity on the clustering coefficient Cp, characteristic path length Lp, local efficiency Eloc, global efficiency Eglob. (Bottom row) Box-plots show the median, interquartile range, and range for each parameter in each condition. Each horizontal line and the associated number indicate the p-value of a post-hoc paired t-test (two-tailed). RS: resting-state, VSW: visual stimulus watching task, VSD: visual stimulus decision task.
Mentions: Despite the small-world architecture in these brain functional networks, significant differences in the network topological properties were observed. ANOVA revealed significant main effects of task demands on all eight network global parameters across the three cognitive conditions (Table 1). In addition, post-hoc comparisons showed that Cp, Eloc and Eglob monotonously increased and Lp decreased in response to the task demands ranging from RS to VSW, and then to VSD (Fig 2). This result suggested that the greater the visual task complexity, the more efficient the network, but with less small-worldness. Fig 2 also shows the individual within-subject effect of task demands on these parameters. In addition, the wiring-costs described by K and Dp, both monotonously increased from RS to VSW, and then to VSD (Fig 3A), suggesting that the brain functional network simultaneously sacrifices a certain cost to meet the demands of complex tasks. Moreover, we observed that the greater the visual task complexity, the less modularity (i.e., decrease of Q) in the functional networks (Fig 3B).

Bottom Line: Compared with the resting-state, the functional networks associated with the visual tasks exhibited significantly increased network efficiency and wiring-cost, but decreased modularity and network robustness.Moreover, at the regional level, we observed that the increased nodal efficiencies in the visual and working memory regions were positively associated with the increase in task complexity.Together, these results suggest that the increased efficiency of the functional brain network and higher wiring-cost were observed to afford the demands of visual tasks.

View Article: PubMed Central - PubMed

Affiliation: Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China.

ABSTRACT
Neuroimaging studies have demonstrated that the topological properties of resting-state brain functional networks are modulated through task performances. However, the reconfiguration of functional networks associated with distinct degrees of task demands is not well understood. In the present study, we acquired fMRI data from 18 healthy adult volunteers during resting-state (RS) and two visual tasks (i.e., visual stimulus watching, VSW; and visual stimulus decision, VSD). Subsequently, we constructed the functional brain networks associated with these three conditions and analyzed the changes in the topological properties (e.g., network efficiency, wiring-cost, modularity, and robustness) among them. Although the small-world attributes were preserved qualitatively across the functional networks of the three conditions, changes in the topological properties were also observed. Compared with the resting-state, the functional networks associated with the visual tasks exhibited significantly increased network efficiency and wiring-cost, but decreased modularity and network robustness. The changes in the task-related topological properties were modulated according to the task complexity (i.e., from RS to VSW and VSD). Moreover, at the regional level, we observed that the increased nodal efficiencies in the visual and working memory regions were positively associated with the increase in task complexity. Together, these results suggest that the increased efficiency of the functional brain network and higher wiring-cost were observed to afford the demands of visual tasks. These observations provide further insights into the mechanisms underlying the reconfiguration of the brain network during task performance.

No MeSH data available.


Related in: MedlinePlus