Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study

Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation （AMC）, which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children （who accepted the AMC training） and 18 non-trained children. Electroencephalography （EEG） waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that： （a） the abacus-trained group had superior mathematical abilities than their peers; （b） distance effects were found both in behavioral results and on EEG wave- forms; （c） the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; （d） both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation.

A submatrix-based P300 brain-computer interface stimulus presentation paradigm

The P300 event-related potential (ERP), with advantages of high stability and no need for initial training, is one of the most commonly used responses in brain-computer interface (BCI) applications. The row/column paradigm (RCP) that flashes an entire column or row of a visual matrix has been used successfully to help patients to spell words. However, RCP remains subject to errors that slow down communication, such as adjacency-distraction and double-flash errors. In this paper, a new visual stimulus presentation paradigm called the submatrix-based paradigm (SBP) is proposed. SBP divides a 6×6 matrix into several submatrices. Each submatrix flashes in single cell paradigm (SCP) mode and separately performs an ensemble averaging method according to the sequences. The parameter of sequence number is used to improve further the accuracy and information transfer rate (ITR). SBP has advantages of flexibility in division of the matrix and better expansion capability, which were confirmed with different divisions of the 6×6 matrix and expansion to a 6×9 matrix. Stimulation results show that SBP is superior to RCP in performance and user acceptability.