Subject and group level changes and comparison in functional connectivity under low vs. high cognitively demanding naturalistic viewing conditions using fmri

Resting State fMRI is used extensively for analysing brain regions. fMRI is also used to determine task induced activations from cerebral networks. This study involves both rest and task activation data and implements statistical methods applied on Blood Oxygenation Level Dependent (BOLD) signals. The conventional task based designs are very specific and may not reflect day to day activities. The two task conditions in this study are watching a movie called INSCAPE with low cognitive load and segments of contextual Hollywood movies under continuous and natural conditions. The aim is to investigate individual and group level Functional Connectivity changes between REST and the two conditions - INSCAPE and MOVIE. The hypothesis is that the functional networks of INSCAPE emulate Resting State networks more closely than traditional MOVIES if the consistent group level effect is regressed out. Voxel wise regression is used on individual subjects across sessions and between subjects per session. Network Wise Correlation Coefficient Maps were also generated using Power\u27s 264 ROIs. Group level concatenated (cICA), for all conditions, and tensor ICA (tICA) maps for only natural viewing conditions were also generated. A paired t-test was performed between INSCAPE vs. REST and MOVIE vs. REST conditions. The results show that ROIS with significant differences were considerably lower for INSCAPE than MOVIE for an FDR corrected arbitrary threshold of p \u3c 0.0005

Factors Influencing Purchase Intention of Cellular Phones Among the University Students in Bangladesh

Uses of cellular phone among the university students are increasing in Bangladesh. To capture this growing market segment and meeting their diverse demand, it is important for the manufacturers and marketers of cellular phone to know about the factors that these young truly judge. This study is undertaken to find out the factors that affect young Bangladeshi university students’ intention to purchase cellular phone. Through using a structured questionnaire, completed responses of 350 respondents were collected by applying convenience sampling technique. To test the reliability of the collected data, Cronbach’s alpha was measured. Besides this, Regression and ANOVA is used to explain the relationship between the factors affecting university students’ cell phone purchase intention and test the proposed hypotheses. Statistical package for the social sciences (SPSS) version 21.0 was used to perform the statistical tests. This study found significant influence of cell phone price, cell phone feature, brand name and social influence on university students’ cellular phone purchase intention. Findings of the study will help the cellular phone manufacturers and marketers to design their youth centric marketing strategies. Moreover, managerial implications along with the directions for future research have also been discussed. Keywords: Cellular Phone, Purchase Intention, Product Price, Product Features, Brand Name, Social Influence, Ease of Use, Promotion of the Brand. DOI: 10.7176/EJBM/11-2-1

Elucidating the complementarity of resting-state networks derived from dynamic [18F]FDG and hemodynamic fluctuations using simultaneous small-animal PET/MRI

Functional connectivity (FC) and resting-state network (RSN) analyses using functional magnetic resonance imaging (fMRI) have evolved into a growing field of research and have provided useful biomarkers for the assessment of brain function in neurological disorders. However, the underlying mechanisms of the blood oxygen level-dependant (BOLD) signal are not fully resolved due to its inherent complexity. In contrast, [18F]fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) has been shown to provide a more direct measure of local synaptic activity and may have additional value for the readout and interpretation of brain connectivity. We performed an RSN analysis from simultaneously acquired PET/fMRI data on a single-subject level to directly compare fMRI and [18F]FDG-PET-derived networks during the resting state. Simultaneous [18F]FDG-PET/fMRI scans were performed in 30 rats. Pairwise correlation analysis, as well as independent component analysis (ICA), were used to compare the readouts of both methods. We identified three RSNs with a high degree of similarity between PET and fMRI-derived readouts: the default-mode-like network (DMN), the basal ganglia network and the cerebellar-midbrain network. Overall, [18F]FDG connectivity indicated increased integration between different, often distant, brain areas compared to the results indicated by the more segregated fMRI-derived FC. Additionally, several networks exclusive to either modality were observed using ICA. These networks included mainly bilateral cortical networks of a limited spatial extent for fMRI and more spatially widespread networks for [18F]FDG-PET, often involving several subcortical areas.This is the first study using simultaneous PET/fMRI to report RSNs subject-wise from dynamic [18F]FDG tracer delivery and BOLD fluctuations with both independent component analysis (ICA) and pairwise correlation analysis in small animals. Our findings support previous studies, which show a close link between local synaptic glucose consumption and BOLD-fMRI-derived FC. However, several brain regions were exclusively attributed to either [18F]FDG or BOLD-derived networks underlining the complementarity of this hybrid imaging approach, which may contribute to the understanding of brain functional organization and could be of interest for future clinical applications