🔸 Tactile stimuli are delivered using a custom-built miniature ball stimulator equipped with interchangeable aluminum stimulus balls.
🔸 The stimulator provides motion with three degrees of freedom:
- Rotation: generates motion across the skin
- Vertical excursion: adjusts indentation depth
- Arm orientation: controls direction of movement
🔸 Each stimulus ball is easily replaceable and designed to deliver precise motion stimuli by indenting the participant’s fingerpad.
🔸 The grating stimulus ball features a surface engraved with sinusoidal patterns:
- Spatial periods of 1, 2, or 4 mm
- Ridge heights of 250 or 500 µm
- Duty cycle (ridge width / spatial period) of 0.6
Publications
- Yu-Cheng Pei, Tsung-Chi Lee, Ting-Yu Chang, Donald RuffattoIII, Matthew Spenko, Sliman Bensmaia , A multi-digit tactile motion stimulator, Journal of Neuroscience Methods, Volume 226, 15 April 2014, Pages 80-87
- Yu-Chun Hsu, Chun-I Yeh, Jian-Jia Huang, Chang-Hung Hung, Chou Po Hung and Yu-Cheng Pei , Illusory Motion Reversal in Touch, Front. Neurosci., 14 June 2019 | https://doi.org/10.3389/fnins.2019.00605
- Chen, Y., Yeh, C., Lee, T. et al. Relative posture between head and finger determines perceived tactile direction of motion. Sci Rep 10, 5494 (2020). https://doi.org/10.1038/s41598-020-62327-x