The Abacus Training Effect On Brain Plasticity In Children And The Change Of Brain Structure With The Training Time

The plasticity refers to functional and structural changes that occur in the brain to adjust to changes in the external environment or internal milieu. Experiences and skills are now recognized as modulators of brain function and underlying neuroanatomic circuitry. Abacus training is a specific method to gain the mental arithmetic skil1Previous studies have found that parietal and frontal areas were the main cortical areas involved in abacus-based mental calculation (AMC) for abacus experts and it was revealed that long-term training of AMC might enhance the integrity in white matter traces related to the visuospatial processing. However, the neural correlates of numerical memory in abacus-trained children and the abacus training-dependant structural plasticity are still poorly understood. The present study attempts to explore the neural correlates of numerical memory in children after long-term AMC training, by adopting the functional magnetic resonance imaging. By combining the voxel-based morphometry (VBM) and diffusion tensor imaging analyses, we research where and when structural changes occur in both gray and white matter with AMC training.This study was composed of three parts. The first part investigated the effect of long-term AMC training on brain activation. Abacus-trained group demonstrated higher activation than the controls in the right posterior superior parietal lobule/superior occipital gyrus and in the right supplementary motor area (SMA) in both digit and bead comparing tasks. A functional connectivity analysis of the resting brain found that abacus-trained children showed significantly enhanced integration between the right SMA and the right inferior frontal gyrus. In the second part, we investigated where the plasticity occur by the AMC training in macro-and micro-structure. VBM revealed that there was an increase in grey matter (GM) volume in the left inferior parietal lobule and a decrease in GM volume in the left precentral gyrus, inferior frontal gyrus and inferior temporal gyrus/fusiform gyrus of children with abacus training. Furthermore, a group comparison of fiber tracks pathways showed that the fractional anisotropy (FA) values in the left superior longitudinal fasciculus and inferior longitudinal fasciculus were significantly enhanced in the abacus-trained group. In the third part, we investigated when the structural plasticity occur by the AMC training. In term of structural plasticity, motor brain regions occurred earliest, followed by the bilateral fusiform and middle temporal gyrus. We found a decrease of GM in some regions but an increase of FA value in the directly adjacent white matter regions.The main findings of our study were as follows:(1) Abacus-trained group demonstrated higher activation than the controls in the frontoparietal network, which might reflect the extensive engagement of visuospatial strategy in the memory of numerical information. Resting state functional connectivity results reflected that abacus training might enhance the functional integration of the functional related areas.(2) Our findings suggested that long-term AMC training could induce structural brain plasticity from the intracortical GM region to the subcortical WM region.(3) Our results demonstrated that abacus training could induce the functional and structural changes in the children’s brain. It was a gradual process with the training time increase. A decrease in GM volume would prompt an invert effect in adjacent white matter areas.