Finger-Based Numerical Training Increases Sensorimotor Activation for Arithmetic in Children-An fNIRS Study

Abstract

Most children use their fingers when learning to count and calculate. These sensorimotor experiences were argued to underlie reported behavioral associations of finger gnosis and counting with mathematical skills. On the neural level, associations were assumed to originate from overlapping neural representations of fingers and numbers. This study explored whether finger-based training in children would lead to specific neural activation in the sensorimotor cortex, associated with finger movements, as well as the parietal cortex, associated with number processing, during mental arithmetic. Following finger-based training during the first year of school, trained children showed finger-related arithmetic effects accompanied by activation in the sensorimotor cortex potentially associated with implicit finger movements. This indicates embodied finger-based numerical representations after training. Results for differences in neural activation between trained children and a control group in the IPS were less conclusive. This study provides the first evidence for training-induced sensorimotor plasticity in brain development potentially driven by the explicit use of fingers for initial arithmetic, supporting an embodied perspective on the representation of numbers.

Keywords: arithmetic; embodiment; fNIRS; finger counting; finger-based training; single-digit addition; subbase-5 effect.

Figure 1

Experimental setup. (A) The addition task was presented in an event-related design and the children were asked to respond orally after mental calculation. (B) The channels (blue) for the regions of interest (yellow) are mapped on the cortical surface (same positions on the left and right hemisphere). The reference points are P3/P4 and F3/F4 (red) according to the 10–20 system. Abbreviation: IPS—intraparietal sulcus.

Figure 2

Behavioral data of the addition task. Trained children but not control children showed a subbase-5 effect in RT. Error bars indicate 95% CI.

Figure 3

Neural activation of the sub-base effect in single-digit addition. (A) ROIs: Sensorimotor cortex and IPS on the left and right hemisphere. (B) Sensorimotor cortex: Trained children showed a subbase-5 effect in the right sensorimotor cortex and control children in the left sensorimotor cortex. (C) IPS: IPS activation for trained and control children for the subbase-5 effect. Violin plots display the kernel distribution of the neural activation within each ROI; box plots include the interquartile range (IQR = 25–75%) with the horizontal line representing the Median. Abbreviation: IPS—intraparietal sulcus.