This functional magnetic resonance imaging study reports the neural basis of the social influence of observing others’ perceptions in dot-number estimation. We found that the medial prefrontal cortex (MPFC) was associated with the detection of the self-other discrepancy. The posterior part of MPFC was especially functionally connected with the right superior parietal lobule (SPL), which is sensitive to numerical perception. The SPL activation was modulated after observing others’ perceptions in the dot-number estimation task. Furthermore, the multivariate pattern analysis showed that the spatial activity patterns altered after the observation. These suggest that the MPFC detects the self-other discrepancy of numerical perception and communicates with the number-sensitive SPL, and triggers the modulation of the activation in the SPL.

We used SPM12 running on MATLAB software to process the scanned images. We performed slice-timing correction, scan-to-scan realignment, normalization to the MNI space, and spatial smoothing (FWHM = 8 mm). A high-pass filter (cutoff cycle = 128 s) was used to remove low-frequency noise.

In GLM1, brain activation for the number of dots during the stimulus phase was examined.

GLM2 included a condition in the stimulus phase and two conditions (Con and Inc) in the choice phase of the Observation sessions. The contrast of Inc > Con calculated the brain activation associated with the self-other discrepancy.

The image data files (Nifti format) can be opened using SPM, MRIcron, and FSL.