An ERP study of simple addition: the semantics and syntax of arithmetic operation sign.

The aim of the current study was to examine brain activity of adult regular calculators while processing addition sums with different types of answers. The task was a verification task, the incorrect answers were divided into two types: one was comprised of three numbers that do not belong to any additive triplet (such as 2, 4, 7) and it was always near the correct result (± 1); the other was a number which is related to the two numbers which appear in the stimulus but belongs to an incorrect competing triplet of numbers and it was always in a greater distance from the correct answer. Differences were found between the different types of answers in the behavioral reaction time with longest reaction time for the competing triplet and the shortest reaction time for the correct answer. In addition, differences in the latency and amplitude of the N170, N270, N400 and P600 components were found among the different types of answers. It can be concluded from these results that the effect of the interference of the competing triplets is greater than the split effect (distance effect), and that there is a different time zone for coding the numbers and coding of other more general syntactic-semantic arithmetic signs.

Frontal lobe role in simple arithmetic calculations: an fNIR study.

This study aimed to affirm the use of functional near-infrared spectroscopy (fNIR) in examining frontal lobe role during automatic (i.e., requires retrieval from long-term memory) and method-based (i.e., requires calculation) arithmetic processing. Adult university students (math difficulties [MD] and control) performed simple arithmetic calculations while monitored using an fNIR system designed to image regions within the frontal cortices. Addition and subtraction problems presented on a computer screen belonged to one of three categories: triples "under 10" (e.g., 2+3=?, 5-3=?), triples that "break 10" (e.g., 5+8=?, 13-5=?), or triples "including 10" (e.g., 10+7=?, 17-10=?). fNIR recordings indicated significant interactions between type of triple, operation, and group over left frontal lobe, and between type of triple and group over right frontal lobe. Within-group differences among controls were found in the "break 10" triples with higher DeOxyHb level recorded during subtraction processing. Between-group differences were found in the "break 10" and "including 10" triples for subtraction with higher levels of DeOxyHb recorded among controls. Results imply that among adults frontal lobe is still involved during simple mathematical processing and fNIR recordings can differentiate its role in adults of varying mathematical ability.