# Processing the fine-grained features of tactile textures involves the primary somatosensory cortex

## TL;DR

The study shows that the primary somatosensory cortex can encode detailed vibration patterns from tactile textures.

## Contribution

The research demonstrates that S1 processes fine-grained spectrotemporal features of tactile textures using EEG frequency-tagging.

## Key findings

- Oddball responses to spectrotemporal contrasts follow the somatotopic organization of S1.
- S1 encodes complex vibration patterns associated with tactile textures.
- EEG frequency-tagging reveals S1's role in dynamic tactile discrimination.

## Abstract

Dynamic tactile perception and discrimination of textures require the ability to encode and differentiate complex vibration patterns elicited at the level of the skin when sliding against a surface. Whether the primary somatosensory cortex (S1) can encode the fine-grained spectrotemporal features distinguishing textures remains debated. To address this question, electroencephalography (EEG) frequency-tagging approach was used to characterize responses to vibrotactile oddball contrasts between two textures. In a first session designed to identify the topographical distribution of responses originating from the hand and foot representations in S1, standard and deviant stimuli were pure sinusoidal vibrations differing in frequency and intensity. In a second session, standard and deviant stimuli were two different snippets of bandpass-filtered white noise matched in terms of intensity and average frequency content, but differing in terms of their complex spectrotemporal content. Using the S1 functional localizer, we showed that oddball responses to a spectrotemporal contrast follow the somatotopical organization of S1. Our results suggest that the encoding of fine-grained spectrotemporal features associated with different vibration patterns involves S1.