# Touch spanning spatial scales: The neural basis of texture perception in somatosensory cortices

> **NIH NIH R01** · UNIVERSITY OF CHICAGO · 2020 · $349,167

## Abstract

PROJECT SUMMARY
Our sense of touch endows us with an exquisite sensitivity to surface texture. We can discern surfaces whose
elements are tens of nanometers in size and hundreds of nanometers apart. The perception of texture not only
allows us to make fine discriminations – like telling real silk from fake silk – but also guides object manipulation.
Indeed, our perception of the surface properties of objects informs how much grip force we apply on them: more
force is required for slippery objects. One of the remarkable aspects of tactile texture processing is that it
operates over six orders of magnitude in element sizes, from the smallest discernible elements (on the order of
tens of nanometers) to the largest elements that can fit on a fingertip, measured in tens of millimeters. We have
shown that this wide range of scales is accommodated by distributing information across three types of nerve
fibers, each sensitive to surface elements over different spatial scales. Importantly, these different afferents
convey texture information differently. Coarse textural features, on the order of millimeters, are conveyed in the
spatial pattern of activation in one afferent population, drawing analogies to visual texture representations on the
retina. In contrast, fine textural features – with sizes in the tens of nanometers – are conveyed in temporal spiking
patterns in two other afferent populations, driven by skin vibrations elicited when the textured surface moves
across the skin, and drawing analogies to audition. How these two types of representations are integrated to
achieve a unitary sensory experience of texture is a mystery. Furthermore, while afferent responses are highly
dependent on exploratory parameters, such as contact force and scanning speed, the perception of texture is
highly invariant with respect to these parameters. Thus, neural signals must be interpreted in the context of how
they are acquired. Nothing is known about how this is achieved.
The goal of the present study is to investigate the neural basis of tactile texture perception in primary and
secondary somatosensory cortices using a large and diverse set of artificial and natural textures across the
range of behaviorally relevant exploratory conditions. First, we will seek to elucidate how texture information is
encoded in cortex, with emphasis on how different neural codes – spatial and temporal – are integrated. Second,
we will examine the relationship between neural responses at each stage of processing and the resulting sensory
experience of texture. Third, we will investigate how the perceptual invariance of texture across scanning speeds
and contact forces is achieved, a mechanism that may be similar to that underlying the pitch-invariance of
auditory timbre. The resulting basic scientific insights will form a foundation for next-generation approaches to
restore the sense of touch through electrical stimulation of somatosensory cortex for use in upper-limb
neuroprosthese...

## Key facts

- **NIH application ID:** 9932515
- **Project number:** 5R01NS101325-04
- **Recipient organization:** UNIVERSITY OF CHICAGO
- **Principal Investigator:** SLIMAN BENSMAIA
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $349,167
- **Award type:** 5
- **Project period:** 2017-06-01 → 2021-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9932515

## Citation

> US National Institutes of Health, RePORTER application 9932515, Touch spanning spatial scales: The neural basis of texture perception in somatosensory cortices (5R01NS101325-04). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9932515. Licensed CC0.

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