Reproducibility and stability of dipole localization of somatosensory evoked magnetic fields: Implications for cortical reorganization

MEG is a neuroimaging technique often used to study changes in the brain’s functional organization. In order to assess changes in functional organization with respect to learning processes or pathology, the localization of the cortical representations of interest must be as accurate as possible. The present study aims to investigate the accuracy of the localization of representations in the primary somatosensory cortex using a classical paradigm to study changes in the brain’s functional organization. We will apply tactile, non-painful stimuli to both corners of the lips and thumbs to estimate the localization of the respective representation in S1. The retest reliability between two measurements (measurements 1 and 2) on the same day and at an interval of one week (measurements 3 and 4) will be considered to assess the reproducibility and stability of the dipole localization. We consider reliability on the same day and on two different measurement days. The comparison of two measurements on the same day (measurement 1 vs. measurement 2 and measurement 3 vs. measurement 4) indicates localization errors due to the methodology itself, e.g., due to slight variations in the stimulation position or the digitization of the head shape. The additional comparison of the measurements at one-week intervals (measurement 1 vs. measurement 3 and measurement 2 vs. measurement 4) allows us to observe a change over time and the stability of the representation over time.