15:00 - 16:30
Tue-P13-Poster II-2
Tue-Poster II-2
Room: P13
The Significance of Structural Rich Club Hubs for the Processing of Hierarchical Stimuli
Tue-P13-Poster II-204
Presented by: Falko Mecklenbrauck
Falko Mecklenbrauck 1, 2, Marius Gruber 3, 4, Sophie Siestrup 1, 2, Dominik Grotegerd 3, Marco Mauritz 5, Anoushiravan Zahedi 1, 6, 7, 8, Ima Trempler 1, 2, Udo Dannlowski 2, 3, Ricarda I. Schubotz 1, 2
1 Department of Psychology, Biological Psychology, University of Münster, Germany, 2 Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Germany, 3 Institute for Translational Psychiatry, University of Münster, Germany, 4 Department for Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital Frankfurt, Goethe University, Germany, 5 Institute for Computational and Applied Mathematics, University of Münster, Germany, 6 Department of Psychology, Humboldt-Universitat zu Berlin, Germany, 7 German Institute of Human Nutrition Potsdam-Rehbrücke, Germany, 8 Neuroscience Research Center, Charité-Universitätsmedizin Berlin, Germany
Human experience contains many instances of nested hierarchical stimuli, such as language or actions sequences. The temporal extension of the different levels, reflected in the dynamics of brain regions, may offer a powerful neural organizing principle for hierarchical stimuli. Based on Gollo et al. (2015), we recorded fMRI and diffusion weighted imaging in 40 participants to test the hypothesis of whether structural rich club hubs are at the top of this processing hierarchy. During fMRI, participants were presented with blocks of digit sequences arranged at different levels of a nested hierarchy. The neurofunctional results showed a general effect of structure bilaterally in the intraparietal area, the left inferior precentral sulcus and the right middle frontal gyrus. Higher levels of structure were associated with more anterior activation in the right superior frontal gyrus. Combining diffusion tensor and generalized Q-sampling imaging approaches, we reconstructed structural networks of the participants and then identified structural rich club hubs in a group average network. To test the correspondence of structure and function, a region of interest (ROI) analysis based on these hub regions and an investigation of the centrality measures of the significant functional clusters were performed. The ROI analysis revealed that activity in the rich club hubs increased with hierarchy levels. Measures of nodal centrality differed among the functional clusters found in the block comparison but did not reveal a consistent pattern. Our results indicate for the first time that structural rich club hubs are involved in the higher-level processing of nested hierarchical stimuli.
Keywords: rich club, hubs, hierarchical processing, connectome, fMRI, DWI, graph theory