Experimental Brain Research

, Volume 216, Issue 2, pp 311–320

Directional remapping in tactile inter-finger apparent motion: a motion aftereffect study

  • Scinob Kuroki
  • Junji Watanabe
  • Kunihiko Mabuchi
  • Susumu Tachi
  • Shin’ya Nishida
Research Article

DOI: 10.1007/s00221-011-2936-0

Cite this article as:
Kuroki, S., Watanabe, J., Mabuchi, K. et al. Exp Brain Res (2012) 216: 311. doi:10.1007/s00221-011-2936-0

Abstract

Tactile motion provides critical information for perception and manipulation of objects in touch. Perceived directions of tactile motion are primarily defined in the environmental coordinate, which means they change drastically with body posture even when the same skin sensors are stimulated. Despite the ecological importance of this perceptual constancy, the sensory processing underlying tactile directional remapping remains poorly understood. The present study psychophysically investigated the mechanisms underlying directional remapping in human tactile motion processing by examining whether finger posture modulates the direction of the tactile motion aftereffect (MAE) induced by inter-finger apparent motions. We introduced conflicts in the adaptation direction between somatotopic and environmental spaces by having participants change their finger posture between adaptation and test phases. In a critical condition, they touched stimulators with crossed index and middle fingers during adaptation but with uncrossed fingers during tests. Since the adaptation effect was incongruent between the somatotopic and environmental spaces, the direction of the MAE reflects the coordinate of tactile motion processing. The results demonstrated that the tactile MAE was induced in accordance with the motion direction determined by the environmental rather than the somatotopic space. In addition, it was found that though the physical adaptation of the test fingers was not changed, the tactile MAE disappeared when the adaptation stimuli were vertically aligned or when subjective motion perception was suppressed during adaptation. We also found that the tactile MAE, measured with our procedure, did not transfer across different hands, which implies that the observed MAEs mainly reflect neural adaptations occurring within sensor-specific, tactile-specific processing. The present findings provide a novel behavioral method to analyze the neural representation for directional remapping of tactile motion within tactile sensory processing in the human brain.

Keywords

Tactile apparent motion Motion aftereffect Remapping Somatosensory Psychophysics 

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Scinob Kuroki
    • 1
    • 2
  • Junji Watanabe
    • 1
  • Kunihiko Mabuchi
    • 2
  • Susumu Tachi
    • 3
  • Shin’ya Nishida
    • 1
  1. 1.NTT Communication Science LaboratoriesNippon Telegraph and Telephone CorporationAtsugiJapan
  2. 2.Graduate School of Information Science and TechnologyThe University of TokyoBunkyoJapan
  3. 3.Graduate School of Media DesignKeio UniversityYokohamaJapan

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