Shared Neural Representations by Touch and Observation
2019년 4월 3일 업데이트됨
Junsuk Kim, Isabelle Bülthoff, Sung-Phil Kim, and Heinrich H. Bülthoff
“Is there a shared neural representation for actual and observed tactile sensation? If it is so, which brain region?”
Previous human neuroimaging studies have reported activation of somatosensory areas not only during actual touch, but also during observed touch. However, it has remained unclear how the brain encodes visually evoked tactile intensities. In this fMRI study, using whole-brain searchlight multivariate pattern analysis (MVPA), we investigated neural representations of perceived roughness intensities evoked by (a) tactile explorations, (b) observation of tactile explorations, and (c) both sensory modalities. MVPA results showed that the five roughness intensity levels, which were perceptually discriminated, could be decoded from neural activity patterns. In the case (a), we found significant decoding performance in the anterior cingulate cortex (ACC) and the supramarginal gyrus (SMG), while in the case (b), the bilateral posterior parietal cortices (PPC), the inferior occipital gyrus (IOG), and the primary somatosensory cortex (S1) were identified to carry the information of visually evoked tactile roughness intensities. In the case (c), we observed shared neural activity patterns in the bilateral insular cortices, the SMG, and the ACC. Interestingly, the insular cortices were identified only from the cross-modal classification analysis, suggesting their potential role in modality-independent tactile information processing. We further examined correlations of off-diagonal entries (pattern of confusion) between perceived and neural similarity matrices for each of the brain regions identified from searchlight analyses. Significant correlations were found solely in the SMG, reflecting a close relationship between neural activities of SMG and roughness intensity perception. The present findings may deepen our understanding of the brain mechanisms underlying intensity perception of tactile roughness.
Junsuk Kim, et. al. (2019). "Shared Neural Representations of Tactile Roughness Intensities by Somatosensation and Touch Observation Using an Associative Learning Method," Scientific Reports, Vol. 9, No. 1, Article number 77.