Characterising brain structures using fractal analysis for Huffaz group

Abstract

Memorising the holy Quran has been the motivation for most Muslims due to the advantages that it offers, in this life and the hereafter. The robust process of memorising the holy Quran is expected to cause changes in the brain regions which is associated with the memory encoding, storage, and retrieval capacity. The main areas in the brain that are involved with memory encoding, storage, and retrieval capacity are the amygdala, hippocampus, cerebellum, and prefrontal cortex. At the moment, the analysis of neuroplasticity is limited to be analysed in binary image because gray-scale analysis requires the usage of more robust image processing techniques. Therefore, this study aims to investigate and characterise the complexity of textual memorisation brain structures using fractal analysis between huffaz and non-huffaz by means of global box-counting analysis, global FFD analysis, and VOI-based analysis. The study recruited 47 participants (mean±SD age, 22.55±1.472 years) from students of IIUM Kuantan Campus. Huffaz group had their 18 months of memorisation training at Darul Quran, Kuala Kubu Bharu, Selangor. The brain MRI images were acquired before being pre-processed using Voxel-Based Morphometry (VBM) toolboxes with MATLAB as platform. Processed images were then thresholded with three thresholding techniques to find the best thresholding method; Otsu, midpoint and hysteresis. Otsu method was proven to be the best thresholding technique (mean±SD, 2.3801±0.953) with a significant difference (p<0.01) tested with ANOVA. Global box-counting and FFD analysis were conducted on the brain MRI images concurrently with VBM to find out the possible brain regions with neuroplasticity. Both analyses found no significant statistical difference between brains of huffaz and non-huffaz (p>0.05), with VBM analysis also could not find any activated voxel brain regions. VOI-based analysis found nine significant areas (p<0.05); two for box-counting analysis (angular gyrus and medial temporal gyrus), six for FFD analysis (BA20, BA30, anterior cingulate, fusiform gyrus, inferior temporal gyrus and frontal lobe), and only a single area (BA33) have shown significant volume differences between huffaz and non-huffaz using VOI-based analysis. BA20 is part of the temporal cortex in the brain, BA30 is located at isthmus of the cingulate gyrus, while BA33 is located at the anterior cingulate gyrus of the brain cortex. All these Brodmann areas involve heavily in memory encoding, memory storage, and retrieval capacity of humans. The results have highlighted the sensitivity of VOI-based analysis because of its local analysis, as compared to the global analysis by box-counting and FFD. These findings have shown that brain neuroplasticity was managed to be detected using VOI-based analysis, and that neuroplasticity due to memorisation process occurred by involving multiple brain areas and regions, and not solely on a single area or a region. To conclude, the application of ability of fractal analysis has been proven to detect structural changes occurrence in brains of huffaz as compared to non-huffaz.