title: Decoding Accuracy in Supplementary Motor Cortex Correlates with Perceptual Sensitivity to Tactile Roughness.
abstract: Perceptual sensitivity to tactile roughness varies across individuals for the same degree of roughness. A number of neurophysiological studies have investigated the neural substrates of tactile roughness perception, but the neural processing underlying the strong individual differences in perceptual roughness sensitivity remains unknown. In this study, we explored the human brain activation patterns associated with the behavioral discriminability of surface texture roughness using functional magnetic resonance imaging (fMRI). First, a whole-brain searchlight multi-voxel pattern analysis (MVPA) was used to find brain regions from which we could decode roughness information. The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP). Next, we evaluated the behavioral roughness discrimination sensitivity of each individual using the just-noticeable difference (JND) and correlated this with the decoding accuracy in each of the four regions. We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA. Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA.
authors.affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.
authors.forename: Junsuk
authors.initials: J
authors.lastname: Kim
authors.affiliation: IBS Center for Neuroscience Imaging Research, Sungkyunkwan University, Suwon, Republic of Korea.
authors.forename: Yoon Gi
authors.initials: YG
authors.lastname: Chung
authors.affiliation: IBS Center for Neuroscience Imaging Research, Sungkyunkwan University, Suwon, Republic of Korea; Department of Global Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
authors.forename: Jang-Yeon
authors.initials: JY
authors.lastname: Park
authors.affiliation: School of Biomedical Engineering, Konkuk University, Chungju, Republic of Korea.
authors.forename: Soon-Cheol
authors.initials: SC
authors.lastname: Chung
authors.affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea.
authors.forename: Christian
authors.initials: C
authors.lastname: Wallraven
authors.affiliation: Department of Brain and Cognitive Engineering, Korea University, Seoul, Republic of Korea; Department of Human Perception, Cognition and Action, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
authors.forename: Heinrich H
authors.initials: HH
authors.lastname: Bülthoff
authors.affiliation: Department of Human and Systems Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
authors.forename: Sung-Phil
authors.initials: SP
authors.lastname: Kim
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D004056:Differential Threshold; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D014110:Touch / Q000502:physiology*; D055815:Young Adult