# Effects on nonverbal numerical acuity performance after a single-session transient random noise stimulation over the intraparietal sulcus or dorsolateral prefrontal cortex

## TL;DR

This study explores how a single session of brain stimulation affects number estimation skills, finding that stimulating one brain region improves accuracy but not speed.

## Contribution

The study demonstrates that tRNS over the intraparietal sulcus improves numerical acuity accuracy in a single session.

## Key findings

- tRNS to the intraparietal sulcus improved accuracy on a number line estimation task.
- tRNS to the dorsolateral prefrontal cortex had no significant effects on task performance.
- A single session of tRNS can enhance numerical acuity without affecting response speed.

## Abstract

We investigated the effects of cognitive training with transcranial random noise stimulation (tRNS) applied to the intraparietal sulcus (IPS) or dorsolateral prefrontal cortex (DLPFC) on improving a multidirectional number line estimation task. We predicted that a single session of tRNS targeting IPS would enhance accuracy without affecting response speed, while a single session of tRNS targeting the DLPFC would improve response speed without influencing accuracy. Through a repeated measure within-between-subject design, 39 healthy participants (M = 21.39, SD = 2.64) were divided into either an IPS (n = 20) or DLPFC (n = 19) bilateral stimulation group, whereby in a counterbalanced order, the participants received a sham session and a session of tRNS separated by 1 week. Stimulation was paired with training tasks focused on the approximate number system. Participants were measured by their speed and accuracy on a multidirectional number line estimation task. Findings partially support predictions, tRNS to the IPS improved accuracy but not speed on the number line estimation task after a single session. Contrary to expectations on tRNS to the DLPFC, no effects were observed. Findings contribute to our understanding of using a single session tRNS as a tool in interventions aimed at maths low achievers.

The online version contains supplementary material available at 10.1038/s41598-025-21890-x.