A multi-voxel pattern analysis of neural representation of vibrotactile location

Previous neural decoding studies have mainly focused on discrimination of activation patterns evoked by active movements. Nonetheless, comparatively, little attention has been devoted toward understanding how brain signals are observed with passive stimulus. In this study, we examined whether the stimulus locations on between fingers, one of the most fundamental features of passive vibrotactile stimulation, can be distinguished from human functional magnetic resonance imaging (fMRI) data. Whole brain searchlight multi-voxel pattern analysis (MVPA) has found two brain regions, which make a contribution to decode stimulus sites, in contralateral posterior parietal cortex (PPC) and contralateral secondary somatosensory cortex (S2). No significant area for the decoding of activity to stimulus site in primary somatosensory cortex (S1), which is well-developed brain region for finger somatotopy. On the other hand, a whole brain univariate group analysis has discovered activity in S1, not in PPC and S2 areas. These results suggest that PPC and S2 regions play a key role in the differentiation of passive vibrotactile stimulus locations, and thus decode tactile events from finger somatotopic.