Textural processing is an ultimate issue for elucidating naturally occurring tactile phenomenon in humans. However, this has not yet been accomplished on the electrophysiological basis due to the difficulty in adjusting the stimulus parameters among the different textural materials. We addressed this issue by using a novel textural stimulator and somatosensory evoked magnetic fields (SEFs).
Methods
We adopted a non-magnetic motor-driven textural stimulator to maintain constant angular velocity and friction force, and evaluated SEFs in 10 healthy participants. Three different textiles were randomly presented to the right index finger: nanofiber textiles (fine-textured) with and without checked pattern, and nylon textile (non-textured).
Results
SEFs were consistently recorded in the primary somatosensory area (SI) at around 50–100 ms, whereas those of the secondary somatosensory areas were variable among the participants. The SI responses were significantly larger for the fine-textured stimuli, but the checked pattern did not affect the amplitude.
Conclusions/Key message
Current study is the first to provide evidence for textural processing in SI by means of SEF. Interestingly, not all the textural properties were reflected to the SEFs despite that SI is important for spatial information processing. Thus, a higher-order processing should be assessed using time-frequency analysis.
