Multimodal connectivity analysis

Introduction: Creative thinking and reasoning are the paramount of human cognitive capacity and one of the most complex systems. These 2-way interactive and dynamic systems have a great strategic value in terms of sustainability and quality of human life. In spite of many scientific research done in this area, underlying neural mechanisms of these cognitive processes have not been discovered yet. With help of advances in neuroimaging it has been possible to model an fMRI experiment using "Semantic Distance" and "Analogy Based Reasoning". Aim of this study is, investigate whole brain and its sub-divisions as a network and interacting pair of nodes while performing an analogy based reasoning test and resting state by increaisng the number of MRI modalities with rs-fMRI and dwMRI. Method: 30 participants aged between 20-35, who doesn't have any psychiatric disorders have been included in this study. All MR scans are completed at Ege University Hospital 3T MR Unit, using previously selected best fit parameters. 3D T1-wieghted MP-RAGE and 60 directions dwMRI data collected for structural and 28 minutes task-based and 9 minutes resting state fMRI data collected for functional analysis. After quality control and preprocessing steps all data analysed using Freesurfer software suite and CONN toolbox. Diffusion weighted images analysed with FSL-ProbtrackX-Tracula software using gloval probabilistic tractography, assesing connectivity of gray matter surfaces. All software was used on this study was open source and licensed under GPL. Results: We found significant BOLD signal correlated regions in the left hemisphere Intraparietal Sulcus, Anterior Cingulate Cortex-Ventral part, Middle Frontal Gyrus, in the right hemisphere Anterior Cingulate Cortex-Ventral part and in subcortical areas, right and left Caudate Nucleus. Left IPS and right IFJ were significantly IIIcorrelated with task performance while in resting state and therefore showed a strong functional connection. We analysed 16 major white matter tracts using global probabilistic tractography, but couldn't find any significant correlations. However, applying Graph Theory analysis of ROI based probabilistic tractography using white- matter surfaces, we found significant correlations between task score and vertex- level attributes in the following areas; left hemi: Medial OFC, Pars Orbitalis ,ACC Rostral, Amigdala and right hemi: Pars Triangularis, Precentral Gyrus, Postcentral Gyrus, Superior Frontal Gyrus and Cuneus. Conclusion: Similar cortical regions were found correlated with creative thinking and reasoning as previous studies suggested. In addition to previous findings we showed functional and structural connectivity properties of the human brain in relation with creativity and reasoning. In future studies it is important to asses the connectivity of these spesific areas and their network properties as they are shown to be linked with creativity and reasoning.