Comparison of two different approaches for brain activity detection in fMRI: SPM-MAP and SPM-GLM
The functional MRI (Magnetic Resonance Imaging), fMRI, is today a widespread tool to study and evaluate the brain from a functional point of view. The blood-oxygenation-level-dependent (BOLD) sig- nal is currently used to detect the activation of brain regions with a stimulus application, e.g., visual or auditive. In a block design ap- proach the stimuli (called paradigm in the fMRI scope) are designed to detect activated and non activated brain regions with maximized certainty. However, corrupting noise in MRI volumes acquisition, patient motion and the normal brain activity interference makes this detection a difficult task. The most used activation detection fMRI algorithm, here called SPM-GLM (1) uses a conventional statistical inference methodology based on the t-statistics In this paper we propose a new Bayesian approach, by modeling the data acquisition noise as additive white Gaussian noise (AWGN) and the activation indicators as binary unknowns that must be esti- mated. Monte Carlo tests using both methods have shown that the Bayesian method, here calledSPM-MAP, outperforms the traditional one, here called SPM-GLM, for almost all conditions of noise and number of paradigm epochs tested.
- [Show abstract] [Hide abstract] ABSTRACT: Since block paradigm was the basic and frequently used paradigm for fMRI study, there are a lot of protocol design that had been used among the researcher. This study modified the frequently used mathematics working memory protocol in block paradigm and compared them in order to get the reliable protocol between them. Two functional magnetic resonance imaging (fMRI) protocols for mathematics working memory functions (cognitive) were developed and conducted to 8 volunteers. Both protocol used block paradigm design, first protocol (frequently used by other researchers) used 180 measurements while the second protocol (newly modified) used 371 measurements. Each volunteer was given several set of arithmetic question in fMRI and need to answer them by mental calculation using both type of protocols. All the raw data from both protocol were analyzed and compared by Statistical Parametric Mapping (SPM8) to get the most significant results protocol for arithmetic task. The results obtain showed that the second protocol (newly modified) produced better significant activation in frontal lobe, parietal lobe and temporal lobe for mathematics working memory functions, while the first protocol (frequently used) get poor result which is only activated in occipital lobe for visual information processing functions and no other activation cluster in another brain area.0Comments 0Citations