The brain is a complex system with the characteristic of transitioning between the ordered and disordered phases around an optimal point, criticality. Many studies focus on exploring the brain behaviors around criticality. However, complexity and variability in the criticality also make the work more challenging. Here, we are intrigued to investigate the highly organized phase, the avalanche or avalanche peaks, which can also be represented as the few gigantic peaks in the global fMRI signal. We explored different timing patterns around the rapid phase transition of the avalanche peaks using statistical and image processing methods. The first approach measures the relative peaking time to the avalanche peak throughout the brain. The following conditional probabilistic group analysis generates a sequence of brain maps describing avalanche evolution. The second method used the modified Principal Component Analysis for Sliding Window (mPCASW) to decompose the signal into components and extract the ordering of components showing positive quadratic patterns around the avalanche. The conditional probabilistic results from the first approach identified representative regions at each stage and showed different trajectories in separate regions. We also found that, in most of the primary components of the mPCASW method that behaved in specific patterns around the avalanche, they revealed the ordering in the Brodmann area regions’ activations. These pattern behaviors are consistent across the population. We believe there could be a meaningful interpretation that can be extracted in the future.
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