An exploratory study on default mode network's time course analysis

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Enformatik Enstitüsü, Sağlık Bilişimi Anabilim Dalı, Türkiye

Tezin Onay Tarihi: 2012

Öğrenci: BURAK AKIN

Danışman: DİDEM GÖKÇAY

Özet:

At resting state, some parts of the human brain is more active than the other areas. Furthermore, the resting state activity in these areas exhibit a sudden decrease when the same areas are recruited in a task. Default mode network (DMN) is one of the resting state networks in the human brain, revealed through functional magnetic resonance (fMR) data acquisition while the subject is in an idle state. The aim of this study is to examine time-course properties of resting state default-mode network by using independent component analysis. Two different conditions are used for this purpose, based on Independent Component Analysis (ICA) method: In the first condition, the whole-brain, including GM, WM, CSF areas are admitted for analysis; in the second condition ICA is performed only for the cortical gray matter voxels, which contain the actual neuronal bed from which the BOLD signal in the fMR images are obtained. Our results indicate that performing ICA exclusively on the GM areas does not provide extra benefit, on the contrary, it spoils the inherent characteristics of the fMR signal as observed in some higher order statistics such as increased skewness and kurtosis.